Article

Emulsifier-free Water-in-Diesel emulsion fuel: Its stability behaviour, engine performance and exhaust emission

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Abstract

Water-in-Diesel emulsion fuel (W/D) is an alternative fuel which progressively intrigues the world attention due to its great impact to the environment as well as energy consumption. However, the high dependency on surfactant for the production of W/D makes it non-effective in terms of cost, and this restricts the commercialization of said fuel. This paper presents the first time ever that W/D without surfactant is being used in a conventional compression ignition engine. Diesel fuel and water, being stored in different units, are quantitatively transferred and instantaneously emulsified by a mixing system combination of high shear mixer and ultrasonic mixer before the produced emulsion fuel is transferred into the engine. The non-surfactant emulsion fuel so called unstable emulsion fuel, labelled as UW/D, is tested in a single cylinder, direct injection diesel engine. The engine is tested under four different load conditions (1 kW (25%), 2 kW (50%), 3 kW (74%), 4 kW (100%)) and with a constant speed of 3000 rpm. As for comparison, a surfactant added emulsion called as the stable emulsion (SW/D), and neat diesel fuel (D2) are also tested. 5% of water is used for both unstable emulsion and stable emulsion. The surfactant used for making the SW/D is SPAN 80 with 0.2% of volume fraction. The engine testing result showed that emulsion fuel without surfactant UW/D does give significant improvement to the engine with a 3.59% increase in brake thermal efficiency (BTE) and 3.89% reduction in brake specific fuel consumption (BSFC) as compared to diesel fuel. In addition, Nitrogen Oxides (NOx) and Particulate Matter (PM) contents in the exhaust emission reduced significantly compared to neat diesel fuel with the average reduction of 31.66% and 16.33% respectively. Overall, the concept of producing and supplying the emulsion fuel in real-time into the engine without having surfactant was proved to be working and functioning through this research while maintaining its benefits; greener exhaust emission and fuel saving.

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... Apart from fuel quality enhancement through nanoadditives and surfactant studies, there are a few studies heading toward a different research direction, which is producing WD without the presence of surfactant and/or additives, the so-called emulsifier-free WD or nonsurfactant emulsion fuel (NWD) [6,9,10]. This fuel is considered as unstable emulsion fuel when the fuel will reach to sedimentation within less than 60 s. ...
... The NWD was made by continuously mixing water and diesel through an in-line mixing system and directly supplied into the engine, thus eliminating the need for high-stability emulsion. Ithnin et al. [6] tested the NWD in a single-cylinder diesel engine through an in-line mixing system that consists of a combination of high-shear mixer and ultrasonicator. The result revealed that the NWD does give substantial improvement to the engine, with a 3.89% reduction in BSFC and 3.59% increase in BTE as compared to diesel fuel. ...
... Due to the attraction of the van der Waals forces, the thin film thickness rapidly decreased over a short period of time. Once the droplet film reached a critical value, it broke and lead to newly formed droplets to move to each other, forming a larger droplet [6]. However, the system employed the concept of continuously mixing biodiesel fuel with steam through an in-line mixing column before the produced fuel is directly supplied into the engine. ...
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The focus of this work is to investigate the effect of emulsifier-free emulsion fuel via steam emulsification (SD) to the diesel engine through physical properties, combustion performance, and exhaust analysis, and compare with conventional emulsion fuel with water percentages of 5% and 10% (E5 and E10) and biodiesel blend (B5). The SD was prepared using a custom 200 mL glass mixing column. The B5 fuel quantitatively was filled in the column, and then the steam was injected from the bottom of the mixing column through the porous frit glass with the pores ranging from 40 to 100 µm. The average water droplet size of SD is 0.375 µm with the average water percentage of 6.18%. The brake specific fuel consumption (BSFC) and brake thermal efficiency (BTE) of SD improved 4.19% and 3.92%, respectively, as compared to B5. The in-cylinder pressure (ICP) was lower than B5, however, yielding close to the B5 at 4 kW engine load. As for the exhaust emission test, NOx and PM for SD were reduced significantly with a percentage reduction of 25.22% and 10.68%, respectively, as compared to neat B5. The steam emulsification method offers a huge potential to be explored further as the concept offers the alternative method of making emulsion fuel without the use of conventional mechanical mixers.
... 9,10 In this regard, a number of attempts have been made to observe the performance of the engine using WED which revealed an increase in BSFC and reduction in power output while NOx emissions were reduced significantly. 8,[11][12][13][14][15][16] Subramanian and Ramesh observed the impact of WED on the performance and emissions characteristics of a single cylinder CI engine by varying loads at the constant speed of 1500 rpm using a 40% ratio of by mass of water and indicated a reduction in the NOx and smoke level along with improvement in the brake thermal efficiency. 17 A similar results are mentioned by Lif and Holmberg using the water content ranging from 5% to 45% where NOx and PM were decreased 30% and 60% respectively with 15% water in the diesel. ...
... However, this decrease was accompanied by a higher level of contents of CO and HC as the percentage of water was increased in the diesel. 18 Ithnin et al. 11 noticed that BTE was increased by 5.34% when 5% water was blended with petroleum diesel. They used a direct injection diesel engine with an emulsified diesel running at 3000 rpm. ...
... Therefore, the use of water emulsion in a diesel engine is an economical way to reduce emissions as no engine design modification is needed to control the production of the pollutants. 6,11 Moreover, the fractional amount of water present in the diesel can significantly reduce the net fuel cost. 19 However, despite a number of investigations to analyze the performance and emissions characteristics of CI engine by employing water diesel emulsion, its comprehensive effect on smoke and noise level is not available. ...
Article
Full-text available
Despite a number of efforts to evaluate the utility of water-diesel emulsions (WED) in CI engine to improve its performance and reduce its emissions in search of alternative fuels to combat the higher prices and depleting resources of fossil fuels, no consistent results are available. Additionally, the noise emissions in the case of WED are not thoroughly discussed which motivated this research to analyze the performance and emission characteristics of WED. Brake thermal efficiency (BTE) and brake specific fuel consumption (BSFC) were calculated at 1600 rpm within 15%-75% of the load range. Similarly, the contents of NOx, CO, and HC, and level of noise and smoke were measured varying the percentage of water from 2% to 10% gradually for all values of loads. BTE in the case of water emulsified diesel was decreased gradually as the percentage of water increased accompanied by a gradual increase in BSFC. Thus, WED10 showed a maximum 13.08% lower value of BTE while BSFC was increased by 32.28%. However, NOx emissions (21.8%) and smoke (48%) were also reduced significantly in the case of WED10 along with an increase in the emissions of HC and CO and noise. The comparative analysis showed that the emulsified diesel can significantly reduce the emission of NOx and smoke, but it has a negative impact on the performance characteristics and HC, CO, and noise emissions which can be mitigated by trying more fuels variations such as biodiesel and using different water injection methods to decrease dependency on fossil fuels and improve the environmental impacts of CI engines.
... This early evaporation leads to an explosion, atomizing large emulsion drops into smaller ones, accelerating fuel drops vaporization, and homogenizing the air-fuel mixture [21][22][23][24][25]. Given the unique features of water/diesel emulsion fuels attributed to the micro-explosion phenomenon, many studies have been undertaken on the combustion behavior of such easy-to-make fuel blends [26][27][28][29]. ...
... Incorporating water into diesel markedly mitigated NO x emissions due to a reduction in the adiabatic flame temperature provoked by the high latent heat of evaporation of water [14,105,120,125]. Likewise, Ithnin et al. [26], Farfaletti et al. [126], Jazair et al. [127], and ...
Article
This study was set up to model and optimize the performance and emission characteristics of a diesel engine fueled with carbon nanoparticle-dosed water/‎diesel emulsion fuel using a combination of soft computing techniques. Adaptive neuro-fuzzy inference system tuned by particle ‎swarm algorithm was used for modeling the performance and emission parameters of the engine, while optimization of the engine operating parameters and the fuel composition was conducted via multiple-objective particle ‎swarm algorithm. The model input variables were: injection timing (35–41° CA BTDC), engine load (0–100%), nanoparticle dosage (0–150 μM), and water content (0–3 wt%). The model output variables included: brake specific fuel consumption, brake thermal efficiency, as well as carbon monoxide, carbon dioxide, nitrogen oxides, and unburned hydrocarbons emission concentrations. The training and testing of the modeling system were performed on the basis of 60 data patterns obtained from the experimental trials. The effects of input variables on the performance and emission characteristics of the engine were thoroughly analyzed and comprehensively discussed as well. According to the experimental results, injection timing and engine load could significantly affect all the investigated performance and emission parameters. Water and nanoparticle addition to diesel could markedly affect some performance and emission parameters. The modeling system could predict the output parameters with an R² > 0.93, MSE < 5.70 × 10⁻³, RMSE < 7.55 × 10⁻², and MAPE < 3.86 × 10⁻². The optimum conditions were: injection timing of 39° CA BTDC, engine load of 74%, nanoparticle dosage of 112 μM, and water content of 2.49 wt%. The carbon dioxide, carbon monoxide, nitrogen oxides, and unburned hydrocarbon emission concentrations ‎were found to be ‎7.26‎ vol%‎, ‎0.46 vol%‎, ‎95.7‎ ppm, and‎ 36.2 ppm, respectively, under the ‎selected optimal operating conditions while the quantity of brake thermal efficiency was found at an acceptable level (‎34.0‎%).‎ In general, the applied soft computing combination appears to be a promising approach to model and optimize operating parameters and fuel composition of diesel engines.
... For instance, water-in-oil emulsions have been used in a scheme to control combustion efficiency and related characteristics, such as flame location, instability, and emission. In practice, the emulsions have been adopted in various practical combustors to reduce NOx emissions [1][2][3][4][5], and improvement of thermal efficiency has been reported [4,5]. In particular, it was expected that the preemptive vaporization of dispersed water droplets would occur when the emulsion droplet was heated to exceed the boiling temperature of the water, which would accelerate the breakup and consecutive combustion performances. ...
... For instance, water-in-oil emulsions have been used in a scheme to control combustion efficiency and related characteristics, such as flame location, instability, and emission. In practice, the emulsions have been adopted in various practical combustors to reduce NOx emissions [1][2][3][4][5], and improvement of thermal efficiency has been reported [4,5]. In particular, it was expected that the preemptive vaporization of dispersed water droplets would occur when the emulsion droplet was heated to exceed the boiling temperature of the water, which would accelerate the breakup and consecutive combustion performances. ...
Article
Multicomponent liquid fuels such as nanofluids and water-in-oil emulsion have been used to control combustion dynamics and pollutant emissions. Similarly, experimental studies on the micro-explosion phenomena of multicomponent liquid fuels have been conducted to enhance the performance of spray combustion. However, the differences in their breakup mechanisms have not been clarified. In this study, breakup characteristics were investigated by introducing irradiation from a pulse laser on a single liquid droplet of n-dodecane and its mixture with nanoparticles or dispersed water droplets. First, the properties of the nanoparticle fluid and the water-in-oil emulsion were compared. After that, various breakup and dynamic behaviors were categorized into three regimes based on the location of breakup due to energy absorption, which is determined by the additive concentration. That is, there was a self-focusing regime (F-regime), an absorption regime (A-regime), and a transient regime between them (T-regime). In addition, detailed breakup characteristics were classified into four-modes depending on the energy level: a no variation mode, an oscillation and puffing mode (OP), a swelling and breakup mode (SB), and an intensive breakup mode (IB). Transitions between the regimes or the modes are described in a map and their criteria were discussed. Two representative characteristics of the secondary droplets (e.g., number and size) were investigated. Different trends appeared according to the concentration and type of additives, and some empirical scale-relationships were suggested. Finally, differences in the breakup mechanisms of the nanofluid and the emulsion were explained.
... In contrast, other studies have observed a significant increase in BTH attributed to better emulsion combustion characteristics. Contrary to the previous findings, some researchers [5,19] found a remarkable reduction in BSFC and a significant increase in thermal efficiency in the emulsified fuel compared to that of neat-diesel fuel. The decrease in BSFC may be attributed to the distribution of dispersed water droplet size in the base fuel, as it affects facilitating and promoting the strength of micro-explosion [20]. ...
... An increase in engine efficiency by up to 20% and a reduction in NOx emission by up to 25% when using a sizeable dispersed phase as reported by Attia and Kulchitskiy [21]. However, with small dispersed droplet size, the BSFC reduced by 5.55% compared to 3.89% in the case of a large dispersed droplet size [5]. All these contradictory findings are related to the complexity of the emulsified fuel combustion behaviour. ...
Article
Water-in-diesel emulsion plays a vital role in the reduction of NOx and PM emissions. Spray droplet micro-explosion is a crucial aspect that requires indepth investigation to provide a detailed analysis of the fuel atomisation and combustion. This study is one of the foremost attempts to examine the microscopic spray atomisation and evaluate the emulsified fuel droplet behaviour. A set of water-in-diesel emulsions is prepared and tested in a constant volume chamber in an evaporating condition. The microscopy lens is attached to a high-speed camera, and high spatial and temporal resolutions through a LED system are used for the visualisation. A purpose-built algorithm is utilised for the spray measurements. The measurements indicate that the emulsified fuel penetrates farthest with a wider cone angle compared to the neat-diesel. The initial spray development suggests droplet puffing/micro-explosion. An observation of a highly deformed droplet shape is caused by droplet puffing/micro-explosion. The Sauter mean diameter (SMD) value increases with the increase in water content due to the water evaporation inside the droplet is greater than the drop off caused by droplet evaporation, suggesting that the spray droplets may undergo puffing/micro-explosion in a short time.
... At 1.03 bar BMEP, the test rig's in-cylinder wall and gaseous temperatures are low, which is not adequate to accelerate the endothermic reaction of water particles, effectively [25,26]. Meanwhile, at high BMEP conditions, the combustible mixture accelerates the evaporation rate of emulsion fuels and promotes an improvement in BSFC, especially for PD10W emulsion fuel [27]. At 3.09 bar BMEP condition, 10% water in base fuel reduces the BSFC by 3.6% compared to base fuel. ...
... Due to the high pressure and temperature at the combustion home, the water particles are energized and atomized effectively at high BMEP conditions. As a result, fine air-fuel mixing is formed inside the combustion home, which leads to low brake-specific fuel consumption [27]. The engine performance is affected by blending 20% of water in diesel fuel since the IDP is notably increased. ...
Article
The current study deals with the high intense water in diesel fuel to endorse better energy and environmental impression from present diesel engines. Though the existence of water in diesel fuel abridges the pollution and progresses the performance, the engine exhibits high vibration and rough operation at high water concentration. To keep the benefits of water in diesel, a novel approach has been attempted in the present study by adding 2-Ethylhexyl nitrate (EHN) as a cetane improver. Test fuels were prepared with different percentages of water and mass fractions of EHN in diesel, and the properties were measured. The assessment of test fuels was carried out in a diesel engine at different brake mean effective pressure conditions. The assessment report specifies that the emission parameters are improved for 10% water emulsified diesel fuel (PD10W) compared to pure diesel (PD), and a negative impact is noted for 20% water emulsified diesel fuel (PD20W). Similar trends are noted for emulsion fuels toward performance parameters. Additionally, the peak in-cylinder pressure and net heat release rate values of emulsion fuels are increased compared to PD and outlying from the top dead center (TDC). An incidence of 1000 ppm of EHN in PD20W emulsion fuel effectively enhances the engine's performance and emission behaviors, and the peak value of combustion parameters is contiguous to TDC.
... Of course, the lowest BSFC value belonged to the B15W5-GQD60 sample at 1800 rpm for which the BSFC value was decreased by 8.8% compared with the B15. The results of Ithnin et al. also demonstrated that adding 5 vol% water to the diesel fuel can decrease the brake specific fuel consumption by 3.89% [32]. Furthermore, based on results of Agbulut et al., adding metal oxide nanoparticles, such as Al 2 O 3 , TiO 2 , and SiO 2 , to the diesel fuel, can reduce the BSFC [33]. ...
... Elsanusi et al. reported that adding water to the mixture of diesel-biodiesel can reduce the NOx emission and by increasing the water concentration up to 15 wt%, the NOx amount was decreased [34]. Moreover, Ithnin et al. revealed that adding 5 wt% to the diesel fuel decreased the NOx emission by 31% [32]. ...
Article
In this research, for the first time a mixture of diesel-biodiesel-water-bionanoparticles was prepared to simultaneously optimize the fuel consumption, reduce pollutant emission, and enhance the performance of diesel engines. To this end, graphene quantum dots as biodegradable nanoparticles were synthesized through the hydrothermal method. In this respective, the synthesized quantum dot nanoparticles were added at the concentrations of 20, 60, and 100 ppm along with 1, 5, and 10 vol% distilled water to the B15 fuel (the diesel fuel containing 15 vol% biodiesel). The results obtained from the engine experiments exhibited that when water and quantum dots were added simultaneously to the B15 fuel, the engine power was increased and the brake specific fuel consumption was reduced. In addition, the emissions of pollutants including HC, NOx and soot were decreased. However, the soot emission was slightly increased by adding the nanoparticles. For the sample containing 5% water and 60 ppm graphene quantum dot nanoparticles, the engine power was improved by 13.6% and the brake specific fuel consumption was reduced by 7.8% compared to those of the B15 pure fuel. Furthermore, emissions of pollutants including NOx, HC, and soot were decreased by 3.8, 29.2, and 33.7%, respectively, compared with the B15 pure fuel.
... The emulsion fuels show lower brake power compared to diesel fuel but better than biodiesel blended fuel; this was due to micro explosion phenomenon which produced more atomization ratio and increased combustion efficiency. Ithnin [32] mentioned that emulsion fuel benefits the environment as energy usage of NO x and PM is reduced to 31.67% and 16.33% respectively and improve the combustion efficiency with 3.89% fuel saving and 3.59% increased thermal efficiency compared to neat diesel [32]. Pullen and Saeed [33] concluded that biodiesel's higher density and oxygenated structure results in proportionally lower energy content. ...
... The emulsion fuels show lower brake power compared to diesel fuel but better than biodiesel blended fuel; this was due to micro explosion phenomenon which produced more atomization ratio and increased combustion efficiency. Ithnin [32] mentioned that emulsion fuel benefits the environment as energy usage of NO x and PM is reduced to 31.67% and 16.33% respectively and improve the combustion efficiency with 3.89% fuel saving and 3.59% increased thermal efficiency compared to neat diesel [32]. Pullen and Saeed [33] concluded that biodiesel's higher density and oxygenated structure results in proportionally lower energy content. ...
Article
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The main purpose of the study is to characterise the effects of diesel, biodiesel blends B5M10 and B10M10 and emulsion fuels B5M10E3 and B10M10E3 as fuels for the impact on particulate matter emission. Engine tests have been performed to obtain results of engine performance, gas emission and particulate matter with various cycles. Excel analysis methods were used to analyse the data obtained. The B5M10E3 produces lower emission results than B10M10E3 as biodiesel fuel increases the combustion temperature. In conclusion, biodiesel blends able to reduce emissions of particulate matter and gas emissions compared to diesel but increase emissions. Therefore, emulsion fuels B5M10E3 and B10M10E3 can be the best alternative fuel for the future.
... Although the electrification of vehicle is coming, for a long period of time in the future, the market for diesel engines will be continuously growing in China due in large part to higher fuel efficiency compared to gasoline engines 3 . However, exhaust emissions including carbon monoxide (CO), hydrocarbons (properly indicated as CxHy, but typically expressed as HC), especially large amounts of particulate matter has brought about critical environmental and healthy issues 4 , resulting in the implementation of restrictions on diesel exhaust particulate matter (PM) and NOx emissions 5 . To meet the increasing emission regulations, a combination of diesel oxidation catalyst (DOC) and diesel particulate filter (DPF) is used as an efficient diesel engine after-treatment technology 6 . ...
Article
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Catalyzed diesel particulate filters (CDPFs) have been widespread used as a technically and economically feasible mean for meeting increasingly stringent emissions limits. An important issue affecting the performance of a CDPF is its aging with using time. In this paper, the effects of noble metal loadings, regions and using mileage on the aging performance of a CDPF were investigated by methods of X-ray diffraction (XRD), X-ray photoelectron spectroscopy and catalytic activity evaluation. Results showed that aging of the CDPF shifted the XRD characteristic diffraction peaks towards larger angles and increased the crystallinity, showing a slowing downward trend with the increase of the noble metal loadings. In addition, the increase of the noble metal loading would slow down the decline of Pt and Pt⁴⁺ concentration caused by aging. The characteristic temperatures of CO, C3H8 conversion and NO2 production increased after aging, and the more the noble metal loadings, the higher the range of the increase. But noticeably, excessive amounts of noble metals would not present the corresponding anti-aging properties. Specifically, the degree of aging in the inlet region was the deepest, the following is the outlet region, and the middle region was the smallest, which were also reflected in the increase range of crystallinity, characteristic temperatures of CO, C3H8 conversion and NO2 production, as well as the decrease range of Pt and Pt⁴⁺ concentrations. The increase of aging mileage reduced the size of the aggregates of the soot and ash in CDPFs, however, improved the degree of tightness between particles. Meanwhile Carbon (C) concentration in the soot and ash increased with the aging mileage.
... While CO emission deteriorated by 43.64% in E10 fuel usage depending on the water content, CO emissions increased by 78.1% in the use of E20 fuel. Ithnin et al. [61] examined two different emulsion fuels, which they called stable and unstable, in comparison with diesel fuel. The content of the fuel, which they express as a stable emulsion, consists of 94.8% diesel fuel, 5% water, and 0.2% Span80 emulsifier by volume. ...
Article
The present study was devoted to investigating the effect of input parameters-Mono ethylene glycol supported emulsion (MEGSE) ratio and engine speed-on their corresponding engine-out parameters including engine torque, BSFC, BSEC, BTE, CO, NO x , and soot emissions. At full-load condition, the MEGSE concentrations ranging from 0% to 20% were employed, whereas the engine speed varied from 1800 rpm to 3250 rpm. In comparison with neat diesel fuel, the BTE and engine torque decreased at high levels of MEGSE, and the CO, NOx, and soot emissions declined as well. The BSFC and BSEC values of the MEGSE/diesel blends was higher in comparison with base fuel. The response surface method was employed to propose multi-regression models and predict engine performance and exhaust emissions. Besides, the analysis of variance technique was utilized to analyse the derived models in terms of statistical significance. The optimization was performed to maximize engine performance and minimize exhaust emissions. The optimal engine operating conditions were found to be at an engine speed of 2603 rpm and a MEGSE concentration of 15.6%. The findings indicated that at this optimal condition, the values of engine torque, BTE, BSFC, BSEC, CO, NO X , and soot were found to be 17.24 Nm, 28.52%, 505.7 g/kWh, 9.48 MJ/kWh, 2123 ppm, 368 ppm, and 2.24 m − 1 , respectively.
... The high latent heat absorption of water particles during the combustion process reduces the peak flame temperature and results in the lower magnitude of NO x emission. The micro-explosion phenomena associated with water-emulsion fuel lead to better air-fuel mixing and complete combustion that results in the lower magnitude of HC and CO emissions, and improved engine performance (Ithnin et al. 2015(Ithnin et al. , 2018Serrano et al. 2019). However, the endothermic reaction of water particles during the combustion process leads to longer ignition delay period, which may results in rough engine operation (Vellaiyan and Amirthagadeswaran 2017b). ...
Article
The present article details the exhaust characteristics of a CI engine fueled with diesel-water emulsion fuel blends and TiO2 nanoadditive incorporated emulsion fuel blends. BD with different concentrations of water and TiO2 nanoparticle were prepared using mechanical agitation, followed by an ultra-sonication process. The physiochemical properties of test fuel were measured based on EN590 standards, and the results show a good agreement with standard limits. The experiments were carried out in a single-cylinder, four stroke, and natural aspirated diesel engine under different BMEP conditions. The emission characteristics of test fuels show that the water emulsified BDs reduce the NOx and smoke emissions. The HC and CO emissions of water emulsified BD are seem to be higher at low-engine loads, and this trend is reversed at high-engine loads. 10% water in BD reduces the EGT by 8.8% at peak BMEP condition. An inclusion of TiO2 nanoparticle significantly improves the exhaust characteristics.
... For the two Tier-1 non-road C8.3L engines, the emulsified fuel reduced NOx an average of 24.5%, and to a level that was comparable to that for the Tier 2 non-road certified YTs (YT4 and YT5). These reductions are comparable to the reductions seen in other studies (Hoseini and Sobati, 2019;Ithnin et al., 2018;El-Din et al., 2019;Park et al., 2016;Syu et al., 2014;Tzirakis et al., 2006;Vellaiyan and Amirthagadeswaran, 2016). Syu et al. (2014) measured NOx emissions of a 2013 light-duty diesel engine and results showed the emulsified diesel reduced NOx emissions by about 18-45.5% for water contents of 5%, 10%, and 15%. ...
Article
Yard tractors (YTs) are trucks used for moving trailers and containers short distances around freight terminals and port facilities, and their diesel engines contribute significantly to nitric oxide (NOx) and particulate matter (PM) emissions to a port’s inventory for the cargo handling equipment (CHE) category. Over time, tougher regulations have forced the introduction of new engine and emission control technologies to reduce emissions from YTs. This paper reviews the history and emissions from a range of technologies that were introduced during the past years with the understanding that a variety of technology solutions may be used by ports worldwide to address air pollution concerns. These new technologies included: cleaner engines, new liquid and gaseous fuels (natural gas [NG] and liquified petroleum gas [LPG]), and new emission control technology. The results show how technology improvements in YT emissions control technology have led to reductions of >70% in NOx and >90% in PM in the emissions inventories for CHE at ports in Southern California.
... The CO and SFC of E10 and E20 were greater than those of diesel which was ascribed to OH radicals from water converting carbon into CO. Ahmad et al., [17] appraised the performance of emulsion fuels prepared with and without emulsifier. 5% of water was commonly used for both the emulsion fuels. ...
Article
The intent of this study is to improve the engine attributes of a mono-cylinder diesel powertrain by adopting emulsion fuel with nanoparticle additive. TiO 2 , a photocatalytic, self-cleaning agent, was preferred and adopted with emulsion fuels. The current work explores the impacts of titanium dioxide (TiO 2) nanoparticles along with the water-in-diesel (DWS) emulsion fuel on the engine attributes, emission and combustion of a single cylinder diesel engine. Initially, TiO 2 was synthesized using sol-gel mechanizing technique and the size of the nano-particles was obtained between 55 ± 5 nm. Emulsion fuel (DWS-prepared with 10% water + 89.8% Diesel + 0.2% Surfactant) was integrated with TiO 2 in the levels of 30 ppm, 60 ppm, and 90 ppm to form homogenous fuels and designated as DWT 1 , DWT 2 , and DWT 3 using mechanical agitator. The functional categories of the test fuels were interpreted using FTIR (Fourier Transform Infrared spectroscopy). Similarly, fuel properties were evaluated as per the ASTM standards. Further, the prepared fuels were evaluated with mono-cylinder diesel powertrain and its significance along with observations was discussed at low, part and full load conditions. The outcomes were equated with emulsion fuel (DWS) and diesel fuel. The results indicated that at full loads, brake thermal efficiency (BTE) for DWT 3 fuel had gone up by 5.65% on a par with diesel and 2.76% on a par with DWS fuel. Carbon monoxide (CO), unburned hydrocarbon (HC), and Smoke emission got decreased by inophyllum methyl ester; DWS, 89.8% Diesel + 10% water + 0.2% Surfactant; DWT 1 , 89.8% Diesel + 10% water + 0.2% Surfactant + 30 ppm of TiO 2 ; DWT 2 , 89.8% Diesel + 10% water + 0.2% Surfactant + 60 ppm of TiO 2 ; DWT 3 , 89.8% Diesel + 10% water + 0.2% Surfactant + 90 ppm of TiO 2 ; T 30%, 28.68%, and 32.98% respectively for DWT 3 fuel on a par with diesel fuel. However, Oxides of nitrogen (NO x) emission for DWT 3 fuel were recorded with an increase of up to 16.26% and 39.68% when compared to diesel and DWS fuel. Also, the performance and emission attributes of DWT 1 and DWT 2 fuels was stay close to diesel fuel. On the whole, it was recognized that, TiO 2 fused emulsion fuel (DWT) could be a promising alternative fuel for diesel engine without the need of hardware changes in the near future.
... Because of vaporization of water, the peak combustion temperature is lowered and thus NOx formation is reduced. Most studies on water in diesel emulsion showed NOx and PM reductions [109,[117][118][119][120]. Some researches showed the increase in CO and HC emissions when using FWE fuel compared to diesel fuel [109,[120][121][122], but there were opposite cases [117,123]. ...
Article
Marine diesel engines, which provide main power source for ships, mainly contribute to air pollution in ports and coastal areas. Thus there is an increasing demand on tightening the emission standards for marine diesel engines, which necessitates the research on various emission reduction strategies. This review covers emission regulations and emission factors (EFs), environmental effects and available emission reduction solutions for marine diesel engines. Not only the establishment of the emission control areas (ECAs) in the regulations but also many experiments show high concerns about the sulfur limits in fuels, sulfur oxides (SOx) and nitrogen oxides (NOx) emissions. Research results reveal that NOx emissions from marine diesel engines account for 50% of total NOx in harbors and coastal regions. Sulfur content in fuel oil is an important parameter index that determines the development direction of emission control technologies. Despites some issues, biodiesel, methanol and liquefied nature gas (LNG) play their important roles in reducing emissions as well as in replacing fossil energy, being promising fuels for marine diesel engines. Fuel-water emulsion (FWE) and exhaust gas recirculation (EGR) are effective treatment option for NOx emissions control. Common rail fuel injection is an effective fuel injection strategy to achieve simultaneous reductions in particulate matter (PM) and NOx. Selective catalytic reduction (SCR) and wet scrubbing are the most mature and effective exhaust aftertreatment methods for marine diesel engines, which show 90% De-NOx efficiency and 95% De-SOx efficiency. It can be concluded that the integrated multi-pollutant treatment for ship emissions holds great promise.
... Experimental results show that the superheat limit is independent of the volume fraction of hydrous ethanol in the emulsion. Ithnina et al 19 performed an experiment on a single-cylinder engine fueled with diesel fuel, unstable water in diesel emulsion fuel, and stable water in diesel emulsion fuel. Experimental results show that unstable water-diesel emulsion fuel gives a significant improvement in engine brake thermal efficiency (BTE) and BSFC compared with diesel fuel. ...
Article
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In the current study, optimization of the performance parameters like effective power (EP), effective power density (EPD), effective efficiency (EE), and different heat losses with respect to six engine control parameters, that is, emulsion fuel, compression ratio, equivalence ratio, engine speed, residual gas fraction, and fuel injection pressure with three levels of each, were performed. Taguchi method is used to design the L27 orthogonal array, using Minitab17 software. Optimization of individual performance parameters is performed with the signal to noise ratio curve, and Grey analysis is used to optimize the overall output performance parameters. Furthermore, an analysis of variance method is investigated to calculate the contribution percentage of control parameters. The theoretical analysis revealed that the overall optimum response of output parameters is found with 10% blend of water (A3), 18 compression ratio (B3), 0.8 equivalence ratio (C1), 2100 rpm engine speed (D3), 10% residual gas fraction (E3), and 100 kPa fuel injection pressure (F1). The EP and EPD are improved by 9.6% and 9.19%, respectively. Also, an average GRG for optimum response setting coincides with the average GRG value of the initial setting. The resulted optimization models are anticipated to be positive instruction for diesel engine operating parameters.
... Combustion phenomena of water-emulsified oils have been studied mainly since the 1970s [1][2][3]. They have been used in many combustion systems, especially in diesel-engines, for various purposes including flame control, higher efficiency, and NOx reduction [4][5][6][7][8][9][10][11][12]. It is known that there are two types of emulsion structures: water-in-oil (W/ O) and oil-in-water (O/W). ...
Article
Water-emulsified oils have been used in a variety of combustion systems, and their atomization characteristics have been studied to control combustion. In particular, many studies have been conducted on micro-explosions, in which an emulsion droplet is broken up into a number of smaller fragments mainly due to phase change of dispersed micro-scale water droplets. In this study, the breakup phenomena of a free-falling single droplet of water-emulsified liquid-fuels (n-decane, n-dodecane, and n-hexadecane) were investigated experimentally. The external energy of a pulse laser was introduced into the emulsion droplet, after which the dynamic response of the emulsion droplet were examined. It was found that the breakup trends were different depending on parameters such as oil type, oil concentration, and laser energy. The dynamic behaviors were categorized into four regimes, and their criteria were related to the effective Weber number of the emulsion droplets. Their physical characteristics are discussed and some empirical relationships are suggested regarding configurational characteristics such as the swelling scale of a liquid membrane, the number of secondary droplets, and the droplet diameter.
... The utilization of emulsion fuels is also of significant interest in this regard [18][19][20][21][22]. For example, the emulsification method is one of the potentially effective techniques to reduce pollutant emissions from diesel engines [22][23][24][25][26][27][28][29][30]. One of the types of emulsion fuels is the foamed emulsion [31][32][33][34][35][36][37][38]. ...
Article
One of the perspective types of combined fuels is the oil-in-water emulsion foamed with the hydrogen-oxygen mixture. In this paper, the process of combustion of such a system obtained via hydrogen-oxygen mixture bubbling through the heptane-in-water emulsion is considered experimentally for the first time. The main goal of this paper is to study different regimes of foamed emulsion combustion at varying composition of hydrogen-oxygen mixture inside bubbles and heptane content in the emulsion. Flame speed is measured with the use of high-speed filming. It is shown that the use of hydrogen allows increasing the speed of flame propagation through the foamed emulsion, and at certain conditions even detonation onset becomes possible. The detonation in the foamed emulsion is determined by the effect of energy focusing during the collapse of gaseous bubbles. When using a lean hydrogen-oxygen mixture, the dependence of the total burning rate of the foamed emulsion on heptane concentration has a maximum. It is found that when using the stoichiometric hydrogen-oxygen mixture, the flame speed decreases monotonically with the increase in heptane concentration. In the case of a weakly reactive compound of the foamed emulsion, the regime of spinning detonation is possible.
... Por el efecto contaminante que producen los combustibles fósiles; se investiga sobre el uso de alternativos y ecológicos [3]. [4] Los combustibles alternos producidos a partir de materias de base renovables, permiten no solo dejar que se dependa del petróleo para obtener combustibles, sino también una alternativa amigable con el medio ambiente. ...
Article
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The Fourier Transform is applied in the analysis of the surface wear of the annular cam of the high-pressure pump DENSO HP3 using the ecological fuel mixture diesel - surfactant - water at 20%, which is an emulsion of two tense-active non-ionic substances during 200functioning hours at 3000 rpm with inspections performed each 50 hours. The ecological fuel reduces the emissions, enhance the thermal efficiency, torque, and power of the internal combustion motor; as it is shown in the experimental analysis, the precision balance it is detected the reduction of 0.121 grams of mass in the cam, with the digital roughness meter it is determined the roughness Ra on the frontal face of the cam, establishing a 22.23% of wear in relation with the ideal profile of experimentation, for the rear face 40.35% of wear, with the didactic module generated on Matlab for the digital image processing and the Fourier Transform compares the ideal profile and the roughness profile of the annular cam in terms of image frequency, using statistics tools such as the maximum average and the minimum o intensity. The use of the mixture of the diesel-surfactant-water fuel at 20% on the high-pressure pump HP3 generates premature wear on the cam surfaces. With the purpose of generating an investigating contribution, it is included the methodology and the technic of tests and measurements on the dynamometer for estimating the fundamental performance characteristics of the diesel internal combustion motor with this type of fuel.
... Water-emulsified fuels have been adopted in many practical combustion systems to control flame characteristics, including NOx emission [1][2][3][4][5][6]. It is known that there are two types of emulsion structures: waterin-oil (W/O) and oil-in-water (O/W). ...
Article
Various combustion devices are employing water-emulsified fuels to control flame stability and NOx emission, and impinging of emulsion on a hot-surface has been used as one of practical atomization methods. However, reports of experimental results of emulsion breakup after impinging have not been sufficient, particularly when the surface temperature was higher than the fuel boiling temperature. In this study, a premixed flame burner having transparent quartz plates was used as a hot surface. Thus, three-dimensional breakup behaviors of water-in-oil emulsion structures of n-dodecane could be observed not only from the side, but also from the bottom. It was possible to visualize the instantaneous phenomena occurring between the liquid droplet and the hot surface. Three experimental parameters were varied: impinging momentum, surface temperature, and water concentration. The dynamic behaviors of the emulsion droplets after impinging were classified into five regimes. Representative characteristics of the secondary droplets such as number, size, and spatial distribution were quantified. Finally, the breakup mechanism of water-in-oil emulsion on a hot surface was explained and a simple empirical model that can be used in numerical simulation was proposed.
... Previous research indicated that to prevent the stratification of emulsified fuels, emulsions were produced online or burned within a short time after the completion of emulsification (Arshad et al. 2019;Ithnin et al. 2018;Mondal and Mandal 2018;Oh et al. 2019), which increased the running costs and limited the application of emulsified fuels in a diesel engine. Earlier researchers mainly focused on the application of emulsified oil with a water content below 20% in diesel engines because guaranteeing the stability of emulsified fuel with high water content is challenging (Choi and Lee 2019; Feng et al. 2015;Jhalani et al. 2019;Syafiq et al. 2017). ...
Article
The application of heavy fuel oil (HFO) in high-speed diesel engines is a practical approach to reducing running costs. However, the physical and chemical properties of HFO may lead to a poor burning rate and increase pollutant emissions. Emulsified HFO has been studied and applied for the purpose of improving combustion and emissions of HFO. However, the stability and water content of emulsified HFO need to be improved. In this study, emulsified HFO with high stability and high water content (up to 30%) was investigated to study the combustion and emission characteristics of the HFO, and a simulation combined with experimental methods was used. The microimages obtained using an electronic microscope highlighted the high stability of emulsified HFO. According to the test results on physical characteristics , compared with low-water-content conditions, HFO has a higher viscosity along with a lower surface tension under high-water-content conditions. To investigate the engine performance with the increasing water content in the HFO, the combustion model was calibrated using engine test experiments. The simulation results showed that with the increasing water content of emulsified HFO, the maximum cylinder pressure, heat release rate, and the crank angle (CA) corresponding to 10% of total heat release (CA10) increased, while the CA corresponding to 50% of total heat release (CA50) decreased. In addition, the experimental results of nitrogen oxide (NO x) and soot emissions maintained a consistent downward tendency with the increase in water content. Compared with fueling HFO, burning emulsified HFO with 30% water content can reduce NO x and soot emissions by 40% and 32%, respectively. The simulation contour maps show the corresponding relationships among the temperature, equivalence ratio, NO x , and soot. The hydrocarbon emissions increased with the water content, and the carbon monoxide emissions similarly maintained the same increasing tendency in addition to fueling the emulsified HFO with 10% water content. Consequently, with a higher water content of the emulsified HFO used in the engine, better combustion was observed with reduced emissions.
... 20 Sufficient surfactant is needed for successful coating because it neutralizes electrostatic repulsive forces and balances Van der Waals attraction forces. 21 Significant reductions in BTE were seen when the surfactant content of the produced diesel fuel nanoemulsions was increased to 10% wt. 22 The type of surfactant used has a significant impact on the viscosity of nanofluids. ...
Article
According to this study, nanosized fuel carried additions to the tri-fuel blends on the engine performance and vibrations are investigated in detail. The tri-fuel mix, which is classified as DEE5BD25-Al2O3 np, is composed of diethyl ether (DEE) in the proportion of 5 percent, biodiesel Jatropha methyl ester (JME) in the proportion of 25 percent, and diesel in the proportion of 75 percent. DEE is a well-known high-cetane ignition improver and nanoparticle suspension stabilizer. To achieve the required results, the Al2O3 nanoparticles were sized at 25nm and concentrated from 25ppm to 50ppm in a binary diesel/JME mix. In order to suspend the nanoparticles in this fuel mix, the surfactants Trtion-X100 and Brij58 were selected independently and used in an ultrasonic liquid processor. The introduction of DEE into the binary diesel/JME mix has also changed it with nanoparticles and non-ionic surfactants, resulting in an improvement in the physicochemical characteristics. According to the findings of the testing, TFB with Al2O3 np had a 1.25 % greater brake thermal efficiency than clean diesel. The use of a higher percentage of Al2O3 np is not advised owing to the inactive heat dissipation in the fuel mix, as well as the possibility of a reduction in the chemical activity of the fuel catalyst. The addition of Al2O3 np to this fuel mix decreased NOx emissions by 200ppm compared to the use of straight diesel fuel alone. The results indicate that Brij58 outperformed the Trition-X100 surfactant in TFB, and that the amount of smoke produced is mostly dependent on the surfactant used. Triton-X100 produced less smoke when compared to the Brij surfactant, while Al2O3-B emitted 69.1 HSU compared to 57.7 HSU for Triton-X100. Triton-X100 released less smoke when compared to the Brij surfactant.
... However, water in oil emulsion can be obtained with mixing, whether with a surfactant or without. In both cases, mixing plays an essential role in reducing the water diameter so it can disperse and link to the fuel molecule (Ithnin et al., 2018). ...
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Finding sustainable alternative fuel to substitute fossil fuel is a study area of interest for most organizations and societies. Such alternative energy should keep the balance between emissions improvement and diesel engine performance. Water-diesel (W/D) emulsion fuel is considered as an auspicious alternative fuel that can improve diesel engine performance and lower harmful exhaust emissions. This review critically discusses the effect of the obtained blend on diesel engine performance and emission characteristics based on the available experimental findings in the literature. The review also highlights the concept of water-diesel emulsion fuel, surfactant, and hydrophilic-lipophilic balance value (HLB). The types of emulsion and micro-explosion phenomena were also discussed. According to the literature review, most of the researchers suggested a significant improvement of the environmental footprint when W/D is used to reduce particulate matter (PM) and nitrogen oxides (NO X). However, other studies criticize the increase in carbon monoxide (CO) and hydrocarbon (HC) emissions.
... A considerable number of researchers have proposed various methods about the removal of NOx emission. Presently NOx treatment methods mainly include fuel pre-treatment (Puskar et al. 2018;Ryu et al. 2016;Wei et al. 2018;Anderson et al. 2015), fuel-water emulsion (Attia and Kulchitskiy 2014;Ithnin et al. 2018;Vigneswaran et al. 2018), continuous water injection (Chybowski et al. 2015;Ji et al. 2019), improved injection parameters (Pelic et al. 2020;Grados et al. 2008), and post-treatment technologies. Selective catalytic reduction (SCR) is the most commonly used NOx control technology, which is considered to be a prospective denitrification technology in exhaust with the NOx removal efficiency of 90% (Ni et al. 2020). ...
Article
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High gravity technology, as a process intensification technology, has demonstrated the great advantages in the field of gas purification on account of its excellent mass transfer efficiency and energy-efficient, but it is rarely applied in the field of nitrogen oxides (NOx) purification of marine diesel engine exhaust. In this paper, a high-gravity bowl-shaped-disk rotating bed (HBRB) without catalytic was designed for diesel exhaust after-treatment. A diesel oxidation catalyst (DOC) was installed in the front of the HBRB to regenerate more nitrogen dioxide (NO2) easily reduced by urea. A bench test of a 6-cylinder marine diesel engine with the HBRB was carried out. The effects of the HBRB speeds, urea concentrations, and engine operating conditions on NOx purification efficiency in engine exhaust were experimentally investigated. The experimental result indicates that the maximum NOx removal efficiency of the HBRB can reach 69.1%. The improvement of the NOx removal efficiency is not obvious at the HBRB speed of over 1500 r/min. The pre-oxidation degree of nitric oxide (NO) and urea concentration largely affect the NOx removal efficiency. The HBRB has great potential in marine diesel engine exhaust denitration.
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In this work, diesel–water emulsification to reduce the NOx emissions and unburnt fuel was attempted. Two different diesel–water emulsions along with selected surfactants which are “92% Diesel, 5.5% Water, 1% Tween 20, 1.5% Span 80” and “90% Diesel 7.5% Water, 1% Tween 20, 1.5% Span 80” used for the experimentation work. These two emulsified diesel fuel variants are installed and subjected to testing on the water-cooled diesel engine under variable load condition and at a constant motor speed of 1500 rpm. The engine performance and emissions data of conventional diesel fuel and two diesel–water emulsified fuel variants mentioned above are obtained and compared. The amount of NOx was lower in the emissions of the engine compared to when a conventional diesel fuel is used, yet the engine performance was not compromised even though there is reduction in peak in-cylinder temperature.
Chapter
This paper highlights the potential usefulness of water-in-diesel emulsions when exposed to high-temperature, thereby improving the air–fuel mixing process utilising micro-explosion resulting from multi-component fuel combustion. Although the high injection pressure significantly affects the spray characteristics and fuel mixing process, observation of micro-explosion in the spray is rarely addressed. In this study, an emulsion made with 5%, 10%, and 15% of water by volume is investigated at different injection pressure (500, 750 and 1000 bar). The experiments are conducted in a constant volume chamber under evaporative conditions. A high-speed camera coupled with a long-distance microscope was used to magnify and visualise the spray droplets micro-explosion in the spray. The raw images of spray were then analysed using a purpose-built image processing algorithm to identify both spray penetration length and dispersion angle. Our measurements indicated that the differences in water content (10 and 15%w) suggest an increase in both spray penetration length and cone angle due to fuel evaporation and micro-explosion. Furthermore, the spray breakup enhances with the increase in water content.
Article
In this work the investigations were conducted to examine the effects of silicon dioxide (SiO2) nanoparticle on water diesel emulsified fuel (WDEF) for diesel engine at various injection timings. The base fuel used was D94W5S1 (Diesel 94%, water 5%, and SPAN-80 1%) in which SiO2 nanoparticles were added in the varying dosages of 25, 50, 75, and 100 ppm. The test fuels of WDEF-SiO2 were prepared with the magnetic stirrer and ultrasonication technique and experiments were conducted with the constant speed of 1500 RPM, compression ratio 18 and 23°bTDC injection timing. From the experiments, the test fuel with 50 ppm dosing D94W5S1-Si50 was found to be optimal as it results in a reduction of 52.52%, 29.32%, 69.69%, and 64.28% for NOX, smoke opacity, hydrocarbon, and carbon monoxide emissions respectively as compared to neat diesel at full load condition. Further, the optimal fuel was tested for different injection timing of 19°bTDC, 21°bTDC, 23°bTDC, and 25°bTDC. The results revealed that with the advancement of injection timing to 25°bTDC, brake thermal efficiency increases by 2.61%, brake specific fuel consumption diminishes by 3.7%. Except NOX emissions, which rises by 6.63%, other emissions of smoke opacity, hydrocarbon, and carbon monoxide reduces by 7.41%, 10%, and 50% respectively as compared to 23°bTDC. Finally, it can be concluded that WDEF incorporated with optimal dosing of silicon dioxide nanoparticle at advanced injection timing remarkably reduces the emissions and enhances the performance features.
Chapter
Micro-explosions during the combustion of palm oil water-in-biodiesel emulsified fuel caused simultaneous reduction in both NOx and smoke from the diesel engine exhaust. The existence of water particles in the palm oil biodiesel emulsified fuel cause micro-explosions due to the difference in volatilities and boiling temperatures of the water and biodiesel as the water particles reached their superheated limit first before the biodiesel. In addition, water lowers the adiabatic flame temperature and therefore acts as a heat sink during the combustion process. Ascertaining the occurrences of micro-explosion in the combustion chamber by direct visualisation is a difficult task, however, it can be made possible by observing the trends of the combustion phases. The secondary atomisation caused by the micro-explosion can be depicted on the combustion characteristics curve by determining the heat release rate of combustion. This study aimed to ascertain the occurrences of micro-explosion and reduction in flame temperature by analysing the combustion phases of water-in-palm oil biodiesel in a diesel engine with different blends of emulsified fuels. Emulsified biodiesel fuels with 11% and 13% water by volume blended with palm oil biodiesel were used as fuel in an unmodified single-cylinder direct injection engine at 0%, 25%, 50%, 75% and 100% loads while maintaining the engine speeds at 2000 rpm. WiBE 8-8-13 shows the highest peak for both in-cylinder pressure and heat release rate with 3.87% and 23.51% increase respectively, as compared to B10 fuel at high load condition. The emission characteristics recorded by WiBE 8-8-11 shows lowest emission of NOx by 52.83% but increase the percentage of CO by 43.75% compare B10 fuel.
Article
Water-in-diesel (W/D) emulsion is one of the promising alternative fuel that improves the combustion efficiency of a diesel engine and simultaneously reduces harmful exhaust emissions. To ensure a stable emulsion, surfactant is used during the formation of W/D emulsion which causes additional costs for this alternative fuel. A device called as Real-Time Non-Surfactant Emulsion Fuel Supply System (RTES) was invented to eliminates the use of surfactant and rapidly supply the W/D emulsion to the engine. The efficiency of 1-ton light-duty diesel truck fueled with W/D emulsion fuel produced by RTES was tested. Two types of the experimental method were used which chassis dynamometer testing and on-road are testing. The optimum water percentage and vehicle speed were evaluated from the result of exhaust emissions and fuel consumption measurement. Chassis dynamometer testing showed that the optimum water percentage for DE2 were 6.5% and vehicle speed aimed at 52 km/h was selected as the optimum vehicle speed. In on-road testing, the urban route gave the deficient results for both exhaust emissions and fuel consumption which agree with chassis dynamometer testing result where emulsion fuel is not suitable to be used at low speed vehicle operation.
Article
Global problems such as energy crisis and air pollution issues have motivated researchers to conduct research on water-diesel fuel emulsion as a strategic research works. Researchers agree that water emulsion could reduce emissions of NOx and particulate matters (PM) simultaneously. This paper discusses the parameters that affect the properties and stability of the emulsion, as well as the latest technology in the mixing process of water diesel fuel emulsion. Numerous research activities on different parameters that affect the properties and stability of emulsion have been carried out by many researchers, including the effect of mixing time, temperature, mixing speed, surfactant percentage, and water ratio. In addition to these parameter factors, the mixing technology also play crucial position on the characteristics of the emulsion produced. The size of a water droplet was the character of an emulsion that was strongly influenced by the mixing technology. There were various methods in the mixing process of water emulsion fuels such as ultrasonic vibration, a mechanical homogeniser, mechanical agitators, real-time non-surfactant emulsion fuel system (RTES), rotary high-speed blending machines, stirred high speed, high shear mixers or a combination of several of these methods. In the mixing process, many researchers still use a surfactant as an emulsifier. However, in recent years, surfactants are being minimized and the mixing process has been optimised. In the future, research on emulsion fuel still has excellent prospects, including structured design of experiments, economic studies, engine components, supporting policies for emulsion fuel, and advanced mixing technologies.
Article
For certain years, various researchers are exploring certain alternative fuel which enhances performance and combustion attributes of the engine along with the reduction of harmful emissions particularly nitrogen oxide (NOx) and particulate matter (PM) emissions. The utilization of water diesel emulsified fuel for diesel engines proves to be an emerging technology in this regard. Through this paper, an attempt has been made to review the performance, emission, and combustion characteristics of diesel engine with the utilization of emulsified fuel without any sort of modifications in the engine. Different researchers revealed their findings regarding the utilization of water diesel emulsified fuel for diesel engines. Most of the findings favour the use of emulsified fuel as an alternative fuel for compression ignition (CI) engines. The performance features of diesel engine with emulsified fuel shows marginal difference as compared to that of neat diesel as a fuel. The NOx and PM emissions decreases simultaneously and thus emulsified fuel proves to be an effective solution for NOx and PM emissions trade off relationship. The combustion features are also improved with the use of water diesel emulsified fuel as compared to that of neat diesel as a fuel. Overall, it can be concluded that water diesel emulsified fuel proves to be a significant alternative fuel as environment attributes are improved along with combustion and performance features for diesel engine without any modifications in the engine.
Article
The current study focuses on assessing the impact of water emulsified fuel on single-cylinder diesel engine. The effect of water concentration, homogenizer speed and surfactant concentration on stability of WD emulsion is studied. The performance, emission, and combustion analysis have been carried out by varying compression ratio, injection timing, and injection pressure. It is noted from stability analysis, that 10% water at 15000 RPM homogenizer speed, 1% surfactant mixture is the optimal parameter to achieve stability of WD emulsion. Ignition delay period and combustion duration increases as water concentration is increased in the emulsion. At compression ratio 18, injection timing 23bTDC and pressure 210bar shows reduced carbon monoxide, hydrocarbon, oxides of nitrogen, and smoke emission by 8.3%, 8.57%, 21.25%, and 43.07% respectively compared to standard diesel. The injection pressure of 250bar shows enhanced BTE compared to 210bar and 230bar.
Article
A theoretical investigation is performed to comparatively evaluate the impact of water addition to the intake air (humidification) or in water-diesel fuel emulsion on the performance and emissions in a turbocharged (T/C), heavy-duty direct injection (HDDI) diesel engine. Specifically, three water addition strategies are examined, i.e. intake air humidification, combustion of water-diesel emulsion considering increasing the injector nozzle-holes diameter for keeping constant the injection duration with increasing water content, and combustion of water-diesel emulsion considering variable injection duration with increasing water content. In all those cases, three water percentages were considered, namely 10wt%, 20wt% and 30wt%. For all cases examined, the engine brake power output was kept constant corresponding to 1800 rpm speed and to 25%, 50%, 75% and 100% of full load, equal to the ones corresponding to the baseline case without water addition. From the examination of the theoretical results, it is shown that the use of water-fuel emulsion with increased injection duration results in higher cylinder pressures and bulk gas temperatures during premixed combustion phase compared to the other two water addition strategies whereas, water-fuel emulsion with constant injection duration promotes more the intensification of diffusion combustion phase compared to other two water induction strategies. Use of both water-fuel emulsion strategies result in significant reduction of cumulative soot formation rate compared to intake air humidification. Overall, it can be concluded that the use water-fuel emulsion with constant injection duration can result in simultaneous increase of brake thermal efficiency and significant reduction of exhaust soot and NO values at both partial and full engine load and thus, it is the most beneficial water addition strategy from the ones examined in the present study.
Article
The effects of solid particles or external electric field on the whole micro-explosions, especially bubble nucleation, were explored by molecular dynamics simulation. The corresponding reasons are also revealed. For this purpose, a water-in-oil droplet in nitrogen environment were constructed and the whole micro-explosion processes were simulated. Bubble nucleation time and nucleation temperature were estimated and compared with the cases in presence of solid particles or an electric field. The energy, force and coordination number of the water sub-droplet were explored to clarify the effects of the solid particles or an electric field. Results indicate that the presence of solid particles or an electric field can shorten the nucleation time and lower nucleation temperature, which are effective ways to control the micro-explosion process. Adding solid particles can weaken the potential restriction on water molecules, which much facilitates water molecules evaporations, and the effect is positive correlation with solid particle sizes. The effect of an external electric field on micro-explosion is essentially caused by the reduction of electrostatic potential. In the alternating electric field case, the reason for the faster temperature rise and the shorter nucleation time is that the sinusoidal change of the electrostatic force.
Article
The current study deals with the high intense water in diesel fuel to endorse better energy and environmental impression from present diesel engines. Though the existence of water in diesel fuel abridges the pollution and progresses the performance, the engine exhibits high vibration and rough operation at high water concentration. To keep the benefits of water in diesel, a novel approach has been attempted in the present study by adding 2-Ethylhexyl nitrate (EHN) as a cetane improver. Test fuels were prepared with different percentages of water and mass fractions of EHN in diesel, and the properties were measured. The assessment of test fuels was carried out in a diesel engine at different brake mean effective pressure conditions. The assessment report specifies that the emission parameters are improved for 10% water emulsified diesel fuel (PD10W) compared to pure diesel (PD), and a negative impact is noted for 20% water emulsified diesel fuel (PD20W). Similar trends are noted for emulsion fuels toward performance parameters. Additionally, the peak in-cylinder pressure and net heat release rate values of emulsion fuels are increased compared to PD and outlying from the top dead center (TDC). An incidence of 1000 ppm of EHN in PD20W emulsion fuel effectively enhances the engine’s performance and emission behaviors, and the peak value of combustion parameters is contiguous to TDC.
Article
This work aimed to apply ultraviolet radiation as an alternative treatment to inhibit microbial growth in diesel fuel. Samples of fuel were placed in a reactor equipped with ultraviolet C (UV‐C) radiation lamps (40 W, 253 nm) and a fuel recirculation system. Assays were performed using different UV‐C exposure times (0–360 min), volume (40 and 60 L), and with / without a circulation system. The microorganisms present in diesel were quantified using the drop‐plate technique and spectrophotometric detection (600 nm), and were identified by genetic sequencing. Parameters such as color, specific mass, and kinematic viscosity were evaluated to verify whether UV radiation promotes changes in phyco‐chemical fuel properties. The assay with 360 min of radiation exposure, with a circulation system, caused the microorganism concentration to decrease from 1.50 × 1010 to 3.33 × 102 CFU mL−1, but otherwise did not lead to any significant changes in fuel physicochemical properties. Microorganisms of the genera Staphylococcus sp., Enterococcus sp., Clostridium sp., Enterobacter sp. and Bacillus sp. were identified. It could be concluded that the use of UV radiation as a microbiological control method resulted in a reduction of around 99% in the concentration of the microorganisms. © 2020 Society of Chemical Industry and John Wiley & Sons, Ltd
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The energy need is rising steadily because of accelerated manufacturing development, growing population, increasing urbanisation and economic growth in the world. A huge quantity of fuel is required from various resources to fulfil the energy need. Thus, a large amount of fossil fuels is burned to fulfil the energy demand, which has caused some hazardous effects on the environment. In the present, biodiesel is a very demanding renewable alternative fuel of diesel due to its accessibility, relatively easier manufacturing process and superior fuel characteristics such as storage safety and complete combustion. In this experiment, the effects of diesel-biodiesel blends on the performance of the diesel engine have been carried out experimentally at various loads. The experiment has been conducted on 4-stroke, single-cylinder, water-cooled, variable compression ratio and multi-fuel diesel engine. The engine is fuelled with soybean oil-based biodiesel blends. The fuel is blended in various blend ratios, i.e. D80B20 (80% diesel–20% biodiesel), D70B30 (70% diesel–30% biodiesel) and pure diesel are used to fuel the single-cylinder engine. Also, the performance of the engine is tested by varying the compression ratio. The values of compression ratio, i.e. CR14, CR16, CR18 and CR20, are considered for testing the engine performance. During the engine test, both indicated characteristics and experimental characteristics are found out for each blend and compression ratio. The results reveal that the blend containing 30% soybean biodiesel has better performance than pure diesel. The performance of the engine, fuelled with biodiesel blend B30, is optimum at CR16.
Article
This work deals with the effects of port water injection (WI) on torque and fuel consumption improvements of a port gasoline injection (PFI) boosted Spark Ignition engine. First, an experimental investigation is carried out at high loads and various speeds to acquire performance and combustion data under WI operation. The engine is fully schematized in a 1D commercial code and enhanced by advanced sub-models for the in-cylinder processes description, including refinements for WI impact on flame development and knock onset. The model is validated against experiments at different speed/load points and water amounts. The validated model is utilized in a predictive way for virtual engine re-calibration and re-design aiming to explore WI potentials on the performance increase at full load. A first calibration strategy is proposed with the aim to minimize the brake specific fuel consumption (BSFC) through water injection, with a fixed value of water to fuel mass ratio (W/F = 0.5). The numerical results highlight the potential of water in reducing fuel consumption, reaching a BSFC gain up to 14% at low speed, while greater advantages up to 32% were obtained in the medium/high-speed region, mainly due to suppression of mixture enrichment. Then, a second calibration strategy is conceived to increase the full load torque curve complying with compressor surge, knock and turbine inlet temperature limits, while minimizing the water consumption. The numerical outcomes highlight a maximum increase in torque up to 13.8%, combined with minimal BSFC penalizations compared to the first calibration, and a minimum evaluated W/F≈0.1. The proposed methodology and automatic control strategies prove to be a valid numerical support for an engine recalibration aimed at improving its performance.
Article
The depletion of petroleum diesel has prompted the use of biofuels and other alternative sources of energy. The direct use of neat Crude Palm Oil (CPO) has mostly resulted in the increase of Oxides of Nitrogen (NOx). Emulsification has demonstrated the capability of reducing NOx emissions. An experiment is conducted to investigate the effect of increasing water content in CPO. Water‐in‐CPO emulsions with varying water contents by volume (5%, 10%, and 15%) with 1% SPAN 80 surfactant are labelled as W5CPO, W10CPO, and W15CPO. The fuels were tested on a single‐cylinder diesel generator at 2,900rpm and 3,200rpm with varying electrical load. For all load conditions at 3,200rpm, the smoke opacimeter reading is highest at 35% with W15CPO and the lowest smoke reading is 15% with W5CPO as fuel. The NOx of CPO was higher than ordinary diesel up to 29% at lower load. The NOx emissions of the CPO was reduced when the amount of water was increased. The maximum reduction in NOx of W15CPO was 66% whereas the minimum NOx reduction was 31%. At 3,200rpm and 4kW, the CO emission of W5CPO was 21% lower in relation to CPO. The W5CPO showed a different trend in the exhaust emissions compared to Water‐in‐CPO emulsions with higher water content. Overall, emulsification has the potential to reduce NOx emissions in relation to neat CPO. This article is protected by copyright. All rights reserved.
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The main target of the current research work is effectively eliminating fossil fuel dependency and improving the exhaust air quality of conventional Compression Ignition (CI) engines. This research paper demonstrates for the first time that a nanofluid (water without surfactant) stored in separate tanks can be quantified, collected, and immediately emulsified by a high shear mixer before transfer into the combustion chamber of a diesel engine. The experiment was carried out under different load states (25%, 50%, 75% and 100%) with a constant speed of 1500 rpm. Biofuel was extracted from citronella leaves using an energy-intensive process. The 5% water share was used for preparing the biofuel emulsion and nano-biofuel emulsion. A cobalt chromate nanoadditive was used to make the nanofluid. An experimental investigation was performed with prepared test fuels, namely, ultra-low sulphur diesel (ULSD), 100% Citronella (B100), surfactant-free Diesel emulsion (SDE), surfactant-free bioemulsion (SBE), and Surfactant free nano-bioemulsion (SNBE), in a test engine. The properties of the sample test fuels was ensured according to EN and ASTM standards. The observation performance results show that the SNBE blend exhibited lower BTE (by 0.5%) and higher SFC (by 3.4%) than ULSD at peak load. The emission results show that the SNBE blend exhibited lower HC, CO, NOx, and smoke emissions by 23.86%, 31.81%, 2.94%, and 24.63%, respectively, compared to USD at peak load. The CP and HRR results for SNBE were closer to ULSD fuel. Overall, the novel concept of an RTEFI (Real-time emulsion fuel injection) system was proved to be workable and to maintain its benefits of better fuel economy and greener emissions.
Article
Ceramic membranes for emulsification are generally fabricated by particle stacking. As a result, their small adjacent pore distances and hydrophilicity cause water droplets to coalesce when preparing monodisperse submicron water-in-diesel (W/D) emulsions. Here, we present a two dimensional-modified membrane emulsification model for the first time, with the development of a hydrophobic MXene-modified ceramic membrane with a water contact angle of 144.7 ± 1.2°. Benefiting from their large lateral size, MXene nanomaterials not only increase the distance between channels but also provide longitudinal-lateral transport pathways for dispersed phases. Therefore, the dispersed phase droplets can roll along the interlayer nanochannels of the MXene-modified membrane before converging with the continuous phase, thereby preventing the coalescence of emulsions. The MXene-modified membrane presents an excellent emulsification ability for preparing W/D emulsions, and the resulting diesel emulsions are at a submicron level with a unimodal distribution, an average particle size of 400 nm, and a particle size distribution coefficient of 0.7. This novel MXene-modified membrane for emulsification is of great significance since it provides a simple and promising strategy for the development of monodisperse nano or submicron emulsions.
Article
Apart from the various emission reduction strategies, a novel concept of cow-urine emulsification in diesel has been explored in this study. In India, cow urine is easily and readily available as gomutra distillate. It constitutes of around 95% water and exhibits the benefits of water emulsification to improve the brake thermal efficiency. Additionally, it consists of urea which works as a reducing agent and significantly cuts-down the NOx emissions. Sodium, magnesium, calcium and potassium present in the cow-urine are also expected to enhance the fuel properties as found in various other researches. Emulsions containing 5%, 10%, 15% and 20% (v/v) cow-urine were tested on a stationary C.I. engine. The 15% emulsion was found to be optimum with a remarkable increase in BTE reaching up to 24.8% as compared to 21.9% with base diesel. In emissions, NOx and smoke got reduced by maximum up to 31.8% and 36.9% respectively. At lower loads, the CO emissions were found to be increased but at higher loads, it was also decreased. No significant variation in HC emissions was observed. Overall, cow-urine emulsified diesel fuel was found to be an energy-efficient and cleaner alternative fuel for stationary C.I. engine application.
Article
Water diesel emulsified fuel (WDEF) evolves as a favorable alternative fuel for diesel engines. In this study, the effects of change in injection pressure (IP) on the performance, emission, combustion features of a diesel engine were evaluated by using WDEF with 50 ppm of silicon dioxide (SiO2) nanoparticles. The IP of the diesel engine was varied from 180 bar-220 bar (with a gap of 10 bars). It was revealed that the higher value of IP augmented combustion features of heat release rate, in-cylinder pressure; mass fraction of fuel burnt and means gas temperature. The performance features were also improved by the increment in the IP owing to improved mixing of air with fuel particles. Apart from NOX, emissions of HC, smoke, and CO were reduced at a higher IP of 220 bar. Hence, higher IP results in the improvement of all the features (except NOX) of a diesel engine.
Article
Nanomaterials exhibit excellent properties, allowing them to act as fuel additives to improve diesel engine characteristics. This review highlights the unique potentials of nanomaterials and their activities in diesel engines to achieve lower harmful diesel emissions and better engine performance. The effects of nanomaterial-enriched fuels on engine characteristics and engine subsystems as well as associated opportunities, identified from laboratory test results obtained in recent years, are discussed. On the basis of two criteria, the best nanomaterial-base fuel pairs are identified from the set of the most frequently tested nanomaterials engaged as fuel additives in diesel engines. This is followed by a review of technical challenges that will need to be addressed and resolved to assure practical viability of nanomaterials acting as fuel additives. Finally, the environmental and human health risks, exposed by investigations in recent years, are reviewed. Wherever possible, potential solutions to outstanding problems are addressed and discussed briefly.
Conference Paper
The use of fuel emulsification technology is a promising area of study as an alternative fuel for diesel engines. New investigations concluded with a significant decrease in the emissions of NOx, CO, and unburnt hydrocarbons (HC) with the operation of the diesel engine with water-diesel emulsion formulations. In this research a new kinds of emulsions are prepared by mixed surfactant span-80, to result being the long-term stability of emulsions. Then performance and emission tests were carried out by using the W/D and W/BD emulsions in a single-cylinder diesel engine. The results obtained include; the engine performance of IC has been enhanced with addition of 5% water dosage to pure diesel and B20D80 fuel, the BTE increased by 5.6 and 7.7%, respectively. The increase percentage of CO emission is 1.85–4.69% for 5% W/D emulsion compared with the neat diesel, while it is 0.88–3.93% for 5% W/B20D80 emulsion compared with the B20D80 fuel. Also, the total reduction percentage of NOx emission for 5% W/D emulsion is 8.4% compared with pure diesel and it is 9.8% for 5% W/B20D80 emulsion compared with the B20D80 fuel.
Article
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Non-surfactant Water-in-Diesel emulsion fuel (NWD) has short stability period and tend to separate immediately into water and diesel. NWD needs to be supplied into the diesel engine or combustor as soon as it was formed. Since the combustion and emission performance are closely related to the water content of an emulsion fuel, the immediate water content of NWD needs to be more closely inspected. The ASTM D95 standard provides a method to determine the water content of an NWD, but this method takes a long time to perform (up to 2 hours) and arduous. This paper describes the estimation of water content in a non-surfactant emulsion fuel by bomb-calorimetry, which can deliver quicker results than ASTM distillation. Experiments were performed with samples of emulsion fuel using and void of surfactant. The samples were first homogenized using an ultrasonic bath before they were sent to a bomb-calorimeter. The higher heating value of the emulsion was estimated using the weighted average since the components were deemed to be non-reactive. The bomb-calorimetric results of the non-surfactant emulsion fuel showed a close proximation, while the emulsion fuel with surfactant delivered less conclusive results. It was concluded from this study that an estimation of water content in NWD could be performed using bomb-calorimetry eight times faster than using the ASTM D95 standard with a deviation of maximum 3%.
Article
The diesel engine is a well-known source to supply energy for vehicles such as marine transportation, industrial sectors, road vehicles. However, the large quantity of diesel engine usages in current scenario tends to environmental hazards and that affects the living organisms in a universe. Nowadays, numerous researches have been performed for diminishing the emission of hazardous gases from a diesel engine. For that, the desired amount of water is blended with the engine oil to minimize the particulate matter (PM), carbon monoxide (CO), nitrogen oxides (NOx) emission, and so on. Moreover, thermal effectiveness of the diesel engine was enhanced with the help of emulsion fuel technique. Henceforth, the current investigation presents a review of water emulsified diesel (WED) fuel performance in the traditional diesel engine. Moreover, this paper is mainly focused on the assessment of emission analysis, combustion of fuel, and physical properties of water–diesel emulsion for the diesel engine. The usage of emulsified fuel has enhanced diesel engine operation. Furthermore, the optimal blend ratio improves the fuel-efficient and reduces fuel emission. The entire research papers of all parameters are compared to validate the effectiveness and improvement of engine performance.
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Growing energy demand and rapid growth of population, are the reasons behind the increase in fossil fuel consumption in the transportation sector. In this context, Compression Ignition (CI) engine is most widely employed in marine and inland transportation. However, extensive utilization of diesel prompted a circumstance where the worldwide fossil fuel reserves may run out within a very short period. Moreover, the concentration of environmental hazards from engine exhaust is also increasing simultaneously. These issues have motivated researchers around the globe, towards discovering a sustainable solution in the context of fuel which mitigates environmental pollution without compromising engine performance. Water-diesel emulsification is one of the proposed solutions which comes under fuel up-gradation strategies. Therefore, an effort has been put forward in this paper to review the effects of water-diesel emulsion on the performance and emission characteristics of the CI engine. Except for few contradictions, on a large scale, it has been observed that brake thermal efficiency (BTE) increases and exhaust gas temperature (EGT) decrease when the engine is run by water-diesel emulsified fuel. Brake specific fuel consumption (BSFC) has shown a reducing trend if only diesel consumption is considered as total fuel. The collective insight also reveals that water-diesel emulsion has great potential for the reduction of nitrogen oxides (NOx) and smoke emissions. From a larger perspective, the water-diesel emulsion has the potential of mitigating exhaust pollutants along with improving engine performance simultaneously.
Article
This work aimed to use ultraviolet (UV) radiation to prevent microbial growth in diesel fuel with different compositions. Commercial samples of ultra-low-sulfur diesel (ULSD) and high-sulfur diesel (HSD) fuels with 11% of biodiesel were used as purchased. These samples were incorporated of 20% biodiesel and different amounts of free water (no addition, 2500, and 10,000 mL.m⁻³). All samples were stored for ten days and subjected to UV-C radiation treatment (55 W, 253 nm) for 360 min to reduce the number of microorganisms. Physicochemical parameters, such as water content, kinematic viscosity, density, and oxidative stability, were measured before and after UV-C treatment. The presence of microorganisms was detected by UV–vis spectrophotometry (600 nm) during the simulated storage, before and after UV-C treatment. An increase in the number of microorganisms was observed during the storage period due to the water content. The UV-C radiation reduced the microorganisms, especially in samples with high water content. Low sulfur levels did not affect the efficiency of the treatment. Significant variations in kinematic viscosity and oxidative stability were observed after the treatment. The presence of microorganisms was reduced by more than 50% after the incidence of UV-C radiation. Therefore, UV-C radiation is a promising technique for microbiological control in diesel fuel. These effects can last up to ten days after the first incidence of radiation.
Conference Paper
This paper presents the previous literature on the performance and emissions behavior of compression ignition engines (CI) through the investment of water and fuel emulsions. Diesel engines (CI) are the most widely used internal combustion engines for their high efficiency, as they are characterized by the spread of millions of them within commercial and industrial applications, etc. Therefore, alternative fuels that require complete changes to these types of engines will be uneconomical. Water/fuel emulsions are the best alternative fuel for a compression ignition engine, as it can be prepared for the injection system within the operating procedure without any modifications to the engine. The benefits of this type of fuel lie in the simultaneous reduction of both nitrogen oxides and particulate matter. More so, it increases the combustion efficiency. Micro-explosion is the most important phenomenon of water/fuel emulsion inside the internal combustion engine cylinder. Therefore, this alternative fuel contributed mainly to reducing emissions and improving combustion efficiency. It has operational features, the most important of which are; the type of emulsion, the water dosage, the diameter and penetration length of the dispersed liquid, and the atmospheric conditions. This document discusses many studies were interested with the investment of fuel emulsions to enhancing the combustion process and reduction emissions in diesel engine. It also presents the effect of main parameters on different fuel emulsions. This review includes an explanation of the most important advantages of using emulsifier as an alternative fuel and the most important improvements that have been made to the combustion process inside the engine.KeywordsFuel emulsionsEngine performanceEmissionsFuel technology
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A single cylinder engine study of water-in-Diesel emulsions was conducted to investigate the effect of water emulsion on the engine performance and gases exhaust temperature. Emulsified diesel fuels of 0, 5, 10, 15 and 20 water/diesel ratios by volumes, were used in a single cylinder, direct injection, diesel engine, operating at 1200-3300 rpm. The results indicates that the addition of water in the form of emulsion improves combustion efficiency, the engine torque, power, and brake thermal efficiency increase as the water percentage in the emulsion increases. The average increase in the brake thermal efficiency for 20% water emulsion is approximately 3.5% over the use of diesel for the engine speed range studied. The brake specific consumption and gas exhaust temperature decrease as the percentage of water in the emulsion increases.
Article
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An experimental investigation on exhaust emissions with emulsion fuel was conducted in a diesel engine that equipped with a “Real Time Non-Surfactant Emulsion Fuel Supply System, RTES” under four different loads operations (1, 2, 3 and 4 kW). RTES is a mixing device that able to produces non-surfactant emulsion fuel which is one of the alternative ways to improve the exhaust emissions of diesel engine, especially Nitrogen Oxides (NOx) and Particulate Matter (PM). As for the test fuel, neat diesel (D2) and tap water-in-diesel emulsion fuel (W/D) are tested as a comparison. Based on the experimental results, emulsion fuel decrease NOx radically compare to D2 in all load conditions with an average reduction of 18.99% respectively. As for the PM, emulsion fuel is lower compare to D2 at all load conditions and lowest at high load. However, tap water emulsion fuel shows high formation of Carbon Monoxide (CO) at all load conditions which due to lower combustion temperature. This significant increment is aligned with the reduction of NOx emissions.
Article
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This study reviewed papers related to biofuel emulsion, principally assessing the use of biofuel emulsion. The discussion is focused mainly on three active areas of emulsified biofuel, namely, exploration of various factors affecting the preparation of stable emulsion and its fuel properties, investigation of the effect of water concentration on physicochemical properties of fuel, and observation of the improvement and degradation of combustion, performance, and emission characteristics and the possible methods to enhance these characteristics.
Article
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Emulsion fuel is an unconventional fuel for diesel engines, which can be used without modifications in the engine. The benefits of an emulsion fuel include lowering the emissions of nitrogen oxides (NOx ) and particulate matter (PM) which are harmful to health and cause diesel engines to suffer. This paper explains in detail the effect of water in the emulsion fuel on the emissions of NOx , PM, carbon monoxide (CO), hydrocarbon (HC), smoke and exhaust temperature. Experimental results from various researchers show a decrease in the NOx and PM emissions simultaneously. However, the results with the increasing water percentage in emulsion fuel are not consistent for HC and CO emissions. The water content in emulsion fuel affects the combustion and reduces the peak temperature in the combustion chamber. On the other hand, microexplosion phenomenon occurs and causes an increase in the volatility of diesel fuel which improves the combustion efficiency.
Conference Paper
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In general, water-in-diesel (W/D) emulsion reduces both particulate matter and nitrogen oxides gas emissions level in diesel engine application as compared of using conventional diesel fuel. W/D emulsion was usually produced by addition of water into the diesel fuel with a slight quantity of surfactant at high speed of propeller mixing. The studies examine the result of several aspects on emulsion stability. Investigated variables are type of surfactant, mixing speed and mixing time. Surfactant used are span 80 and many type of glycerines which have been derived from a corn oil, palm oil, soy oil, rice bran oil and sunflower oil. The results show that the type of surfactant gives a big impact on the stability period of the emulsion fuel. The higher mixing speed and less water percentage increase the stability period of W/D emulsion fuel. Optimum mixing time is 5 minutes for W/D emulsion fuel which using Span 80 as surfactant with mixing speed of 2500 rpm.
Article
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The presence of water within diesel fuel in the form of water-in-diesel (W/D) emulsion lowers the pollution level of nitrogen oxides and particulate matter. Emulsion of W/D was prepared by high-speed mixing and gradually adding water into the diesel fuel containing a small amount of emulsified agent. We measured the physical properties of diesel fuel and W/D emulsions with a pycnometer for density, Fann V.G. rotational viscometer (Chandler Engineering, Model 3500, Tulsa, Oklahoma, USA) for viscosity, and a Fisher Surface Tensiomat (Fisher Scientific Co., Model 21, Hampton, New Hampshire, USA) for surface tension. We used a computer image analyzer system to investigate the water droplet fuel interaction and the water droplet distribution within the diesel phase. The results of this study show that the emulsions of 10% and 20% W/D were stabilized for 4 weeks and 10 days, respectively, under the conditions of 0.2% surfactant, 15,000 rpm, and 2 minutes of mixing time. Under the same conditions, the stability period is limited to 5 hours for emulsions with a water concentration higher than 20%. An optimum surfactant concentration of 2% was found for 40% W/D due to the polydispersity behavior of the added surfactant. The water droplet distribution and average diameter were significantly affected by the total number of mixing revolutions. We measured and investigated the physical properties of the stable W/D emulsions in terms of density, surface tension, and viscosity.
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This paper presents the results of an experimental investigation, into the effect of water in diesel and kerosene emulsions, on the evaporation time of a single droplet, on hot surfaces (stainless-steel and aluminum). Experiments are performed at atmospheric pressure, and initial water volume concentrations of 10, 20, 30, and 40%. The wall temperatures ranging from 100–460 C, to cover the entire spectrum of heat transfer characteristics from evaporation to film boiling. Results show that, qualitatively, the shapes of emulsion evaporation curves are very similar to that of pure liquids. Quantitavely, there are significant differences. The total evaporation time, for the emulsion droplets is lower than that for diesel and kerosene fuels, and decreased as water initial concentration increases, up to surface temperatures less than the critical temperature. The value of the critical surface temperature (maximum heat transfer rate), decreases as initial concentration of water increases. In the film-boiling region, the evaporation time for the emulsion droplets is higher than for diesel and kerosene droplets, at identical conditions.
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Diesel engines exhausting gaseous emission and particulate matter have long been regarded as one of the major air pollution sources, particularly in metropolitan areas, and have been a source of serious public concern for a long time. The emulsification method is not only motivated by cost reduction but is also one of the potentially effective techniques to reduce exhaust emission from diesel engines. Water/diesel (W/D) emulsified formulations are reported to reduce the emissions of NOx, SOx, CO and particulate matter (PM) without compensating the engine’s performance. Emulsion fuels with varying contents of water and diesel were prepared and stabilized by conventional and gemini surfactant, respectively. Surfactant’s dosage, emulsification time, stirring intensity, emulsifying temperature and mixing time have been reported. Diesel engine performance and exhaust emission was also measured and analyzed with these indigenously prepared emulsified fuels. The obtained experimental results indicate that the emulsions stabilized by gemini surfactant have much finer and better-distributed water droplets as compared to those stabilized by conventional surfactant. A comparative study involving torque, engine brake mean effective pressure (BMEP), specific fuel consumption (SFC), particulate matter (PM), NOx and CO emissions is also reported for neat diesel and emulsified formulations. It was found that there was an insignificant reduction in engine’s efficiency but on the other hand there are significant benefits associated with the incorporation of water contents in diesel regarding environmental hazards. The biggest reduction in PM, NOx, CO and SOx emission was achieved by the emulsion stabilized by gemini surfactant containing 15% water contents.
Article
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The use of water as an ancillary combustion control technique has recently received renewed interest. This paper historically reviews the applications of water addition to practical combustion systems and discusses in detail the fundamental aspects of combustion which are affected. Combustion properties of water-in-fuel emulsions are elaborated upon, and several potentially favorable applications which require additional research are identified.
Article
Water-in-diesel (W/D) emulsion is one of the promising alternative fuel that improves the combustion efficiency of a diesel engine and simultaneously reduces harmful exhaust emissions. To ensure a stable emulsion, surfactant is used during the formation of W/D emulsion which causes additional costs for this alternative fuel. A device called as Real-Time Non-Surfactant Emulsion Fuel Supply System (RTES) was invented to eliminates the use of surfactant and rapidly supply the W/D emulsion to the engine. The efficiency of 1-ton light-duty diesel truck fueled with W/D emulsion fuel produced by RTES was tested. Two types of the experimental method were used which chassis dynamometer testing and on-road are testing. The optimum water percentage and vehicle speed were evaluated from the result of exhaust emissions and fuel consumption measurement. Chassis dynamometer testing showed that the optimum water percentage for DE2 were 6.5% and vehicle speed aimed at 52 km/h was selected as the optimum vehicle speed. In on-road testing, the urban route gave the deficient results for both exhaust emissions and fuel consumption which agree with chassis dynamometer testing result where emulsion fuel is not suitable to be used at low speed vehicle operation.
Article
Emulsion fuel is one of alternative fuel for diesel engines. This study is to investigate the durability of a diesel engine that is running on emulsion fuels. Two emulsion fuels contain water, low grade diesel fuel and surfactant in the ratio of 10:89:1 v/v% (E10) and 20:79:1 v/v% (E20) has been tested for 200 h. The results of using emulsion fuels were then compared with that of Malaysian conventional diesel fuel (D2). The Nitrogen Oxides (NOx), Carbon Monoxide (CO), Carbon Dioxide (CO2), PM (particulate matter) and exhaust temperature from the tested fuel were measured before and after 200 h durability test. Analyses were also conducted on the wear of the engine components, viscosity change of the lubricant and carbon deposit formation in the combustion chamber. Emulsion fuel operation in the test engine reduced the PM and NOx by 15.47% and 54.40% respectively but CO and CO2 increased by 95% and 34.12% respectively as compared to D2. No abnormal wear could be observed when using emulsion fuels. In addition, emulsion fuels produced less carbon deposit with 65% and 52% reduction for E10 and E20 respectively. All three test fuels exhibits minimal increments in the lubricant's viscosity values after 200 h of engine operation.
Article
In this work, an experimental study is carried out to optically investigate the behavior of a bicomponent emulsion under strong heating. The role of the inner features of the emulsions on the microexplosion phenomenon is quantitatively evaluated. When a water in oil (W/O) emulsion is quickly heated, the internal water droplets do not vaporize exactly at the boiling point, but rather after a permanency in a metastable state. Then, the growth ofsteam nuclei leads to a vigorous expansion. The energy released in this stage breaks the molecular bonds of the surrounding oil, resulting in a fragmentation into numerous and smaller droplets. This physical phenomenon is called microexplosion. The main objective of this work is to study the influence of the dispersed water droplet size of W/O emulsions in the fragmentation effect after the microexplosion. A high-speed visual technique is used to achieve this goal. Emulsions were prepared by using commercially available sunflower oil with high water content (25-35%) and surfactant (Span83). With the Leidenfrost effect device, a single droplet was isolated on a hot surface, and accurate images of the phenomenon were recorded. The results, obtained after the postprocessing of the images, show the existence ofan optimal condition related to the feature of the emulsions, resulting in a fine, homogeneous, and rapid propagation of the fragmented oil front.
Article
The need for more efficient energy usage and a less polluted environment are the prominent research areas that are currently being investigated by many researchers worldwide. Water-in-diesel emulsion fuel (W/D) is a promising alternative fuel that could fulfills such requests in that it can improve the combustion efficiency of a diesel engine and reduce harmful exhaust emission, especially nitrogen oxides (NOx) and particulate matter (PM). To date, there have been many W/D emulsion fuel studies, especially regarding performance, emissions and micro-explosion phenomena. This review paper gathers and discusses the recent advances in emulsion fuel studies in respect of the impact of W/D emulsion fuel on the performance and emission of diesel engines, micro-explosion phenomena especially the factors that affecting the onset and strength of micro-explosion process, and proposed potential research area in W/D emulsion fuel study. There is an inconsistency in the results reported from previous studies especially for the thermal efficiency, brake power, torque and specific fuel consumption. However, it is agreed by most of the studies that W/D does result in an improvement in these measurements when the total amount of diesel fuel in the emulsion is compared with that of the neat diesel fuel. NOx and PM exhaust gas emissions are greatly reduced by using the W/D emulsion fuel. Unburnt hydrocarbon (UHC) and carbon monoxide (CO) exhaust emissions are found to be increased by using the W/D emulsion fuel. The inconsistency of the experimental result can be related to the effects of the onset and the strength of the micro-explosion process. The factors that affect these measurements consist of the size of the dispersed water particle, droplet size of the emulsion, water-content in the emulsion, ambient temperature, ambient pressure, type and percentage of surfactant, type of diesel engine and engine operating conditions. Durability testing and developing the fuel production device that requires no/less surfactant are the potential research area that can be explored in future.
Article
Carbon black (CB), a solid waste obtained from the pyrolysis of waste automobile tyres possesses a considerable heating value in it. In this study, four different emulsions of CB, diesel and water were prepared with the help of a surfactant, by varying the percentages of the CB. An emulsion containing 5% CB was denoted as CBWD5. Similarly, 10%, 15% and 20% CB in emulsion were denoted as CBWD10, CBWD15 and CBWD20, respectively. The emulsion were characterised for their suitability as fuels. Further, they were tested as alternative fuels in a single cylinder, air cooled, direct injection (DI), diesel engine developing power of 4.4 kW at 1500 rpm. The combustion, performance and emission characteristics of the diesel engine fueled with the four different emulsions were compared with the diesel operation of the same engine. The engine was able to run with all the four emulsions without any modification in the engine. The results indicated that the emulsions exhibited longer ignition delay about 1–3°CA, compared to that of diesel at full load. The brake specific energy consumption (BSEC) was higher by about 0.8–25% with the emulsions than that of diesel at full load. The results also indicated that all the emulsions gave lower NO emissions by about 16–42% at full load.
Article
The purpose of this research was to investigate the effects of water concentration in a biodiesel nanoemulsion fuel on engine performance and exhaust emissions of a 4-cylinder diesel engine. Biodiesel nanoemulsions containing 5%, 10% and 15% water were used for the engine tests and the results were compared with B5, B20 and certified #2 diesel fuels. Biodiesel nanoemulsions produced lower NOx emissions and soot opacity than B5, B20 and certified #2 diesel fuels. Biodiesel nanoemulsion with 5% water concentration produced engine power and torque values that were similar to the values measured for B5 fuel. Increasing water concentrations in biodiesel nanoemulsions increased the engine brake specific fuel consumption and CO emissions. The rate of NOx reduction was greater than the rate of CO increase when the water concentration in biodiesel nanoemulsions increased from 10% to 15%. These results provided strong evidences on the effects of increasing water concentration in biodiesel emulsions on reducing NOx and soot from a 4-cylinder diesel engine. Emulsified biodiesel fuel is a promising alternative method for reducing harmful emissions from diesel engines without requiring significant engine modifications.
Article
Automotive Diesel engines exhaust emissions must constantly be reduced to comply with more and more stringent regulations, all over the world. The introduction of water in the combustion chamber is already used on some large marine diesel engines to cut down NOx emission.In this paper an experimental study is conducted on a modern automotive 1.5 l HSDI Diesel engine while injecting a water-in-diesel emulsion (WDE) with a volumetric water-to-fuel ratio of 25.6%. Four injection strategies are considered with and without pilot injection, with two levels of injection pressure. First, the injection of WDE is compared to diesel-fuel in terms of combustion and NOx and PM emissions without using exhaust gas recirculation (EGR). Depending on the WDE fuelling rate and injection strategy (with or without a pilot injection before main injection), NOx emissions are most often reduced (of up to 50%), and PM emission are most often decreased as well (the maximum relative reduction being 94%). The combustion is largely affected by the injection of WDE as compared with pure diesel-fuel, the main observations being an increased of the ignition delay and an improved mixing-process between the fuel and the surrounding gases.After that, the use of WDE in parallel with EGR (with various EGR rates) is tested with the aim at improving the NOx–PM trade-off (reduction of NOx emission at a given PM emission level or reduction of PM emission at a given NOx emission level). The results show that this method is an effective way for NOx and PM emission reduction on an automotive Diesel engine.
Article
Emulsions of diesel and water are often promoted as being able to overcome the difficulty of simultaneously reducing emissions of both oxidises of nitrogen (NOx) and particulate matter from diesel engines. In this work, the performance of an engine together with its effect on environment were tested when engine was powered by both pure diesel and emulsified fuel with various quantities of water content in the diesel fuel. The amount of water quantities added ranged between 5% and 30% by volume. The engine speed during the experimental work was within the range from 1000 to 3000rpm. While producing similar or greater thermal efficiency and improved NOx emission outcomes use of the emulsion also results in an increase in brake specific fuel consumption. It was also found that, at high amount of water addition, the nitrogen oxide decreases. Also, in general, the diesel emulsion fuel emitted an amount of CO2 higher than that of pure diesel.
Article
In this study, the breakup characteristics of secondary atomization of an emulsified fuel droplet were investigated with a single droplet experiment. In the single droplet experiment, the emulsified fuel droplet suspended from a fine wire was inserted into an electric furnace, and then secondary atomization behavior was observed using a high-speed video camera. Moreover, a mathematical model to calculate the generated water vapor at micro-explosion was proposed by using the mass and energy conservation equations under some assumptions. In the proposed model, that can be calculated by using the inner droplet temperature history at micro-explosion. As a result, puffing and micro-explosion occurred even when the fine ceramics fiber was used. The proposed model showed that about 50–70wt% of water in the emulsified fuel changed to water vapor instantaneously at the occurrence of micro-explosion. The mass of water necessary for micro-explosion was shown. The breakup time was closely related to the superheat temperature just before the occurrence of micro-explosion.
Article
A general model of the micro-explosion of emulsified droplets, suitable for both oil-in-water (O/W) and water-in-oil (W/O), is presented. Using this new model, a definition of micro-explosion strength is proposed; also the effects of various parameters on micro-explosion strength are discussed. Although emulsified oils have two different structures and different processes of forming an oil membrane, the definition of micro-explosion strength and its calculation are identical in the general model. The results show that the predictions of the general model agree with experiments. Furthermore, some extra effects, such as the properties of a surfactant, the solubility of a gas and the deformation of a droplet under an aerodynamic force are also discussed.
Article
An experimental study has been carried out to reveal the statistical characteristics for the onset of micro-explosion of an emulsion droplet evaporating on a hot surface. The measurements are made of the waiting time for the onset of micro-explosion at various ambient pressures, base fuels, water contents and surface temperatures. The Weibull analysis is applied to obtain the distribution function of the waiting time for the onset of micro-explosion and to derive the empirical formula for the rate of micro-explosion as a function of the water volume and emulsion temperature. The results show that the waiting time is correlated well with the Weibull distribution of the wear-out type. The waiting time decreases with an increase in the ambient pressure, the saturation temperature of base fuel, the water content and the surface temperature. An empirical formula is proposed for the rate of micro-explosion as a function of the water volume and emulsion temperature.
Conference Paper
Compression ignition engines are the most efficient internal combustion engines. They are well established products and millions of them are already on the market. As a result, alternative fuel that requires complete alteration to these types of engines would be un-economical. Water-in-diesel emulsion is a best alternative fuel for compression ignition engines that can be utilized with the existing engine setup with no engine retrofitting. It has benefits in the simultaneous reduction of both NOx and particulate matters. Furthermore, it has huge impact in the combustion efficiency improvement. Micro-explosion is the most important phenomenon of water-in-diesel emulsion inside an internal combustion engine chamber. It affects both the emission reductions and combustion efficiency improvement directly and indirectly. It is affected by the volatility of the base fuel, type of emulsion, water content, diameter of the dispersed liquid, location of the dispersed liquid and ambient conditions. This review paper addresses the influence of micro-emulsion on the combustion and emission of water-in-diesel emulsion fuel. It also presents the effect of operating parameters on the micro-emulsion.
Article
A novel emulsion fuel with 82.4% diesel, 5% water and 12.6% nano-organic additives by volume is introduced in this work. Unlike other emulsion fuels (milky in color) developed around the world, it is green in color and very stable. The performance and emissions of the diesel engine fueled by the emulsion fuel are tested and compared with that of pure diesel. The results indicate that a better brake thermal efficiency can be achieved with the emulsion fuel. This is due to the micro-explosion phenomenon, i.e. the instantaneous and violent vaporization of the water droplets within the fuel droplets as the fuel is exposed to high temperature gas, large fuel droplets are broken into many smaller droplets, thereby significantly improving fuel vaporization and combustion process. At the same time, NOx emission is reduced because of the presence of water, which brings down the peak flame temperature. The PV diagram is also measured and the heat release rate is calculated. It is found that the ignition delay of emulsion fuel is slightly longer than that of pure diesel, however, the combustion duration is shorter, which further explains why the emulsion fuel can increase the efficiency of the engine.
Article
Physical properties, spray behaviour and combustion characteristics of a water-in-diesel emulsion, a water-in-diesel microemulsion and a conventional diesel fuel were investigated. The size of the drops, in the water-containing fuels, was measured by NMR diffusometry. Spray development and combustion were studied by optical methods in an optically accessed combustion vessel at conditions similar to those in a diesel engine. High speed shadowgraphs were employed to measure break-up, droplets penetration, vapour penetration and start of combustion. Combustion duration, flame temperature and relative soot concentration were determined by emission-based methods. Differences in spray behaviour suggest an enhanced atomisation for the water-containing fuels compared to regular diesel fuel. Moreover, reduced soot concentrations and flame temperature with increased combustion duration were noticed for the water-in-diesel fuels than for the regular diesel fuel.
Article
The combustion of heavy oil and its emulsions with water was investigated in experiments on a semi-industrial scale. Two comparisons between heavy oil and oil-water emulsion flames are presented that, due to the different initial conditions of the spray, provide complementary information. Reported results include spatial distributions in the flame of temperature and species concentrations (O2, CO, UHC, NOx) as well as gaseous and solid emissions in the flue gases. The measurements inside the emulsion flame display a remarkable improvement in the combustion process with respect to that of the neat oil with poor atomization; differences are much less important if a fine spray is achieved with the heavy oil. Solid emissions are significantly reduced in the emulsion tests and the morphology of the particle samples demonstrates the fragmentation of the drops and/or the coke particles initially formed. The flame temperatures are reduced by ∼65 K. The heat absorbed by the water injected in the emulsion and enhanced radiative heat transfer due to the higher particle number density could explain this difference. The spatial distribution of NOx indicates that a significant reduction is obtained in the final part of the flame; this may be attributed to a decrease in the rate of thermal-NO formation as a consequence of lower gas temperatures. No measurable difference in NOx concentration is found in the inner core of the flames.
Article
One of the major technological challenges for the transport sector is to cut emissions of particulate matter (PM) and nitrogen oxides (NOx) simultaneously from diesel vehicles to meet future emission standards and to reduce their contribution to the pollution of ambient air. Installation of particle filters in all existing diesel vehicles (for new vehicles, the feasibility is proven) is an efficient but expensive and complicated solution; thus other short-term alternatives have been proposed. It is well known that water/diesel (W/ D) emulsions with up to 20% water can reduce PM and NOx emissions in heavy-duty (HD) engines. The amount of water that can be used in emulsions for the technically more susceptible light-duty (LD) vehicles is much lower, due to risks of impairing engine performance and durability. The present study investigates the potential emission reductions of an experimental 6% W/D emulsion with EURO-3 LD diesel vehicles in comparison to a commercial 12% W/D emulsion with a EURO-3 HD engine and to a Cerium-based combustion improver additive. For PM, the emulsions reduced the emissions with -32% for LD vehicles (mass/km) and -59% for the HD engine (mass/ kWh). However, NOx emissions remained unchanged, and emissions of other pollutants were actually increased forthe LD vehicles with +26% for hydrocarbons (HC), +18% for CO, and +25% for PM-associated benzo[a]pyrene toxicity equivalents (TEQ). In contrast, CO (-32%), TEQ (-14%), and NOx (-6%) were reduced by the emulsion for the HD engine, and only hydrocarbons were slightly increased (+16%). Whereas the Cerium-based additive was inefficient in the HD engine for all emissions except for TEQ (-39%), it markedly reduced all emissions for the LD vehicles (PM -13%, CO -18%, HC -26%, TEQ -25%) except for NOx, which remained unchanged. The presented data indicate a strong potential for reductions in PM emissions from current diesel engines by optimizing the fuel composition.
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