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Combustion heat release analysis of ethanol or n-butanol diesel fuel blends in heavy-duty DI diesel engine
Abstract
An experimental study is conducted to evaluate the effects of using blends of diesel fuel with either ethanol in proportions of 5% and 10% or n-butanol in 8% and 16% (by vol.), on the combustion behavior of a fully-instrumented, six-cylinder, turbocharged and after-cooled, heavy duty, direct injection (DI), ‘Mercedes-Benz’ engine installed at the authors’ laboratory. Combustion chamber and fuel injection pressure diagrams are obtained at two speeds and three loads using a developed, high-speed, data acquisition and processing system. A heat release analysis of the experimentally obtained cylinder pressure diagrams is developed and used. Plots of histories in the combustion chamber of the heat release rate and temperatures reveal some interesting features, which shed light into the combustion mechanism when using these promising bio-fuels that can be derived from biomass (bio-ethanol and bio-butanol). The key results are that with the use of these bio-fuels blends, fuel injection pressure diagrams are very slightly displaced (delayed), ignition delay is increased, maximum cylinder pressures are slightly reduced and cylinder temperatures are reduced during the first part of combustion. These results, combined with the differing physical and chemical properties of the ethanol and n-butanol against those for the diesel fuel, which constitutes the baseline fuel, aid the correct interpretation of the observed engine behavior performance- and emissions-wise.
... One of the main reasons is its potential as alternative for derivate petroleum fuels. It is a renewable resource and it may be manufactured by fermentation of either sugar-or starch-rich vegetable materials, i.e., corn, barley, molasses, sugar cane, sugar beets, sorghum, etc. [24][25][26][27][28]. Also, other agricultural or municipal residues, i.e., straw and waste from woods, food and paper processing residues are used to produce ethanol under demonstrated processes [29][30][31][32]. ...
... The most important disadvantage is a consequence of its low solubility in diesel fuel, which is caused by the mixture chemical structure, temperature dependence, water content and percentage of ethanol into the blend [34]. Therefore, to solve this issue, different techniques have been applied, including mixing ethanol and diesel fuel just before injection, using an emulsifier or co-solvent, fumigating ethanol to the intake air charge or using a dual injection with a separate injection system for each fuel [7,31,[35][36][37]. The two last options allow higher ethanol concentrations, although engine technical modifications are needed. ...
... After mixing concentrations of ethanol in diesel fuel above 12% [10], it usually forms two different phases, compromising engine functioning. To prevent it, addition of co-solvents [18] or surfactants [31,33] to the blend is recommended. ...
The growing demand for fossil fuels, the rise in their price and many environmental concerns strengthen the incessant search for fuel alternatives. Recently, traffic noise has been described as a threat to human health and the environment, being responsible for premature deaths. In this context, the usage of alcohol/diesel fuel blends in diesel engines has gained increasing impact as a substitute fuel for use in internal combustion engines. Moreover, alcohol can be derived from environmentally friendly processes, i.e., fermentation. Furthermore, alcohols can enhance combustion characteristics due to a rise of the oxygen concentration, thus decreasing major emissions such as soot and reducing knock. The commonly used alcohols blended with diesel fuel are methanol and ethanol, recently followed by butanol. In contrast, there are very few studies about propanol blends; however, emissions reduction (including noise) could be remarkable. In the present work, an analytical literature review about noise and exhaust emissions from alcohol/diesel fuel blends was performed. The literature review analysis revealed a continuous increase in the number of publications about alcohol/diesel fuel blend exhaust emissions since 2000, confirming the growing interest in this field. However, only few publications about noise emission were found. Then, an experimental case study of noise emitted by an engine running on different alcohol (ethanol, butanol and propanol)/diesel fuel blends was presented. Experimental results showed that although diesel fuel provided the best results regarding noise emissions, butanol displayed the least deviation from that of diesel fuel among all tested alcohol blends. It may be concluded that tested alcohol/diesel fuel blends in general, and butanol blends in particular, could be a promising alternative to diesel fuel, considering noise behavior.
... However, it is essential to highlight the significant advantages of using ethanol, including the reduction of CO, HC, SO , NO and CO emissions [15]. Several methodologies have been identified to overcome the aforementioned challenges, with four main techniques emerging for introducing alcohol into CI engines [19,20]: ...
... However, due to the limited miscibility between ethanol and diesel fuels, only a small amount of ethanol (less than 15% (v/v)) is typically allowed in the blending technique to achieve satisfactory results [31,32]. To overcome this challenge, the use of a surfactant or emulsifier becomes necessary to prevent ethanol separation from the diesel fuel and increase its proportion in the blend [20,33]. Therefore, for achieving a complete substitution of diesel oil with a renewable fuel, the fourth option is the most suitable choice. ...
Currently, several studies are being carried out to replace diesel oil with alternative fuels in compression ignition engines. Ethanol is a strong candidate, thanks to its extensive feedstock, low emissions and low cost. Although it also has easy adaptability to engine technologies, there are some difficulties that need to be eliminated regarding its direct use in compression ignition engines (diesel cycle). The present work aims to evaluate the ignition delay of ethanol/peg 600 blends in a four-stroke compression-ignition engine, in relation to maximum pressure and maximum rate of pressure rise under different experimental conditions. Parameters such as engine speed, load and compression ratio, in addition to fuel injection advance and percentage of additive were analyzed. For this study, a code was developed in Matlab computer software capable of analyze data collected through Indicon-AVL, to tests carried out at the Institute of Mobility and Sustainable Energy (IMES - PUC-Rio). From the data generated, it was possible to prove that the use of ethanol additive can be carried out with some modifications in the diesel engine, but adjusting the parameters mentioned above is essential to optimize the combustion process.
... The higher latent heat of bioethanol compared to biodiesel increases the time for fuel vaporization, thus increasing the ignition delay of the blended fuel. In addition, ignition delay is also affected by the low cetane number of the blended fuel [27]. Hence, there is an increase in HC emissions at 10% bioethanol concentration or B40E10, the HC produced was close to B40E0 fuel. ...
... The average decrease in B40E10 was 14.48%, while the addition of 5% bioethanol increased NOx up to 16.23% at 1000-2000 rpm compared to the standard B30 fuel. The decreased NOx emissions with the addition of 10% bioethanol was also obtained in the study of Rakopoulos, et al. [27]. In addition, a 6.9% reduction in NOx emissions was obtained in the test of adding 10% ethanol to diesel fuel by Kim, et al. [23]. ...
The transition of energy sources from fossil fuel to biofuel is becoming a major topic in the world towards renewable energy to reduce greenhouse gas emissions, improve environmental air quality, and reduce dependence on fossil fuel in the future. This study aims to evaluate the effect of increasing the concentration of oxygenated biofuel in diesel fuel on the emissions of diesel engines. In this study, B30 (30% biodiesel and 70% diesel) was used as a base fuel, and a fraction of pure biodiesel (B100) was added to increase the biodiesel concentration in B30 fuel to create B40 (40% biodiesel and 60% diesel). Furthermore, the addition of 5% and 10% of bioethanol as a fuel additive in the fuel blend was conducted while maintaining a biodiesel concentration of 40%. The effect of bioethanol contained in the fuel blends was tested using a single-cylinder 418 cc diesel engine. The experiment was carried out at an engine speed of 1000–3000 rpm. The result shows that the concentration of the diesel-biodiesel-bioethanol blend affected the emissions produced by the diesel engines. Combustion efficiency increased with the concentration of biodiesel in the diesel fuel, as shown by reduced CO emissions, increased CO2 emissions, and increased NOx emissions at engine speeds of 2000–3000 rpm. In comparison to 5% bioethanol at various engine speeds, adding 10% bioethanol has a disadvantageous effect on the combustion process, increasing CO and HC emissions.
... Butanol is a fuel, which can be produced from agricultural raw material using anaerobic fermentation through clostridia [1][2][3] . Butanol has four isomers: 1-or n-, 2-or sec-, iso-, and tert-butanol, only the three first of which occur naturally. ...
... According to the CSP formalism, the species and energy Eqs. (1) and (2) are cast in the form: [22,23] and g (z ) is defined as a summation of 2 K terms: ...
The algorithm of Computational Singular Perturbation is used in order to study autoignition dynamics and formaldehyde emission during isochoric, adiabatic n-butanol oxidation. It is shown that n-butanol autoignition has a significant chemical runaway for low initial temperatures and a limited one for high initial temperatures. Autoignition is supported mainly by the dissociation of H2O2 to OH and, to a lesser extent, by the attack of HO2 on the parent fuel that produces H2O2. The algorithmic analysis points to the pivotal role of mainly H2O2 and secondarily CH2O in the process and it is shown that addition of these two species to the initial mixture can shorten the ignition delay time substantially. The strong effect of H2O2 is based on the near elimination of the chemical runaway, because of the generation of a substantial OH pool very early in the process. The formation of formaldehyde in the products is shown to be practically insensitive to a very wide variety of additives for a given overall equivalence ratio, even when these additives had a substantial effect on ignition delay. This is attributed to the fact that, for combustion with air at a given equivalence ratio, the relative proportion of C/H/O atoms in the initial mixture does not change much, independently of the precise configuration of the molecules that constitute the fuel mixture and the additive. As a result, methodologies for the control and reduction of aldehyde and ketone emissions should be based on equivalence ratio, pressure, and temperature control, rather than the use of additives.
... However, there is scarce literature on heavy-duty diesel engines (HDDEs) running on n-butanol blended diesel. Rakopoulos et al. [28,31] conducted experiments on HDDE using diesel/n-butanol blends with two blend proportions (8% and 16%, by volume) and discovered that nbutanol blended diesel might reduce CO, NO X , and soot emissions. Increased THC emissions were detected when n-butanol blend proportion was increased above 16%, which is related to the slower evaporation, cylinder wall impact, and inferior air-fuel mixing caused by the higher latent heat of vaporization of n-butanol. ...
... The DBu20 blend exhibits the highest BSFC under all tested conditions. This is owing to the lower LHV of n-butanol (refer to Table 4), so a greater amount of fuel is consumed to produce the same power output compared to diesel fuel [31]. At constant low load with varying speed, the DBu20 blend shows an increase of up to 3.2% in the BSFC, while with the DBu5 and DBu10 blends no significant changes are observed compared to diesel. ...
This study focused on the application of a single-zone combustion model together with triple Wiebe functions to analyze the impact of the diesel/n-butanol blends as drop-in fuel in a four-cylinder heavy-duty diesel engine (HDDE). Commercial diesel (EN590) was used as a reference fuel to compare combustion, performance, and emissions characteristics with n-butanol blends of 5%, 10%, and 20%, by volume (DBu5, DBu10, and DBu20) under different speed and load conditions as per the World Harmonized Steady-State Cycle (WHSC). The apparent heat release rate (AHRR) calculated from the model agrees (RMSE ≤ 6.80) with the experimental values. The results show that the DBu5 and DBu10 blend increase maximum in-cylinder pressure and maximum AHRR while the in-cylinder temperature slightly decreases, at low load, without significant changes in ignition delay and combustion duration. The DBu20 blend reduced maximum in-cylinder pressure, maximum AHRR and in-cylinder temperature in all operating conditions, in addition, increased the ignition delay and reduced the combustion duration. Brake specific fuel consumption (BSFC) increases by 0.8-6% with an increase in n-butanol content; however, the addition of n-butanol reduced the brake specific energy consumption (BSEC) by 1.7-2.3%. All n-butanol blends reduced CO and particle emissions, regardless of operating conditions, while THC and NO X emissions increased mainly at full load. DBu10 blend showed better engine performance along with combustion and emission characteristics, which makes it a promising fuel blend as per the current study.
... Since the flame propagates faster due to the utilization of a large volume of gaseous fuel-air combination inside the cylinder by the flame initiated from the numerous ignition centers of the pilot fuel, it results in a greater residual gas temperature [31]. Due to the presence of alcohol in the blended fuel, its reduced cetane number results in longer ignition delay [32,33]. Conversely, a blend with a higher cetane number will ignite more quickly and reduce the ignition delay. ...
... Due to the fall in partial pressure of oxygen caused by the addition of gaseous fuel, the ignition delay of pilot diesel fuel initially increases with an increase in gaseous fuel substitution. Due to the competitive interaction between the gaseous fuel and active radicals of diesel fuel [31,32], these gaseous fuels play an active role in the chemical process prior to ignition, negatively affecting pre-ignition processes and combustion. It is observed that the ignition delay of the fuel is decreased with the addition of DEE in the fuel. ...
Experiments are performed on a diesel engine working in single fuel mode using fossil diesel (FD) as well as 5% and 10% (v/v) di-ethyl ether (DEE) additives with FD as fuels as well as in dual fuel mode using the above fuels as pilot fuels along with producer gas (PG) as primary fuel. This study aims to draw comparative analyses of engine combustion, performance and emission characteristics using the above fuel combinations to establish the most suitable fuel strategy for a diesel engine. The study revealed greater control over nitric oxide (NO) and smoke opacity in dual fuel mode compared to single fuel mode operations. Addition of DEE with FD, produced lower HC and CO emissions, comparable NO emissions along with reduced smoke opacity compared to FD in both modes of operation. Further, in dual fuel mode operation, the diesel percentage energy substitution (PES) reduced with increase in DEE content in the blends. The tradeoff study involving engine performance and emissions with respect to the cost of operation revealed that the fuel strategy used in dual fuel mode operation delivered better engine performance along with reduced NO emission and smoke opacity at lower operational cost compared to all the considered fuel strategy in single fuel mode operation. Especially, FD+5% DEE+PG and FD+10% DEE+PG fuel strategies were found to be the most suitable dual fuel mode combinations in a diesel engine in terms of their superior engine performance, lower emissions along with better economy.
... In fact, butanol-diesel blends did not show blend stability problems along the whole butanol range for temperatures above 0 • C [26]. Butanol-diesel blends do not need emulsifying agents since the blend does not separate even after several days [85]. Ethanol-diesel blend stability problems can be compensated by additivation or adding biodiesel to the blend [54,84]. ...
... Fossil fuels have often been partially replaced by renewable fuels to reduce both the environmental impact and the dependence on conventional fuels in internal combustion engines. Most of the butanol-diesel emission results found in the literature were tested under steady conditions in a Euro 5 (or inferior) engine test bench under warm ambient conditions [19,85,95]. ...
Nowadays, the transport sector is trying to face climate change and to contribute to a sustainable world by introducing modern after-treatment systems or by using biofuels. In sectors such as road freight transportation, agricultural or cogeneration in which the electrification is not considered feasible with the current infrastructure, renewable options for diesel engines such as alcohols produced from waste or lignocellulosic materials with advanced production techniques show a significant potential to reduce the life-cycle greenhouse emissions with respect to diesel fuel. This study concludes that lignocellulosic biobutanol can achieve 60% lower greenhouse gas emissions than diesel fuel. Butanol-diesel blends, with up to 40% butanol content, could be successfully used in a diesel engine calibrated for 100% diesel fuel without any additional engine modification nor electronic control unit recalibration at a warm ambient temperature. When n-butanol is introduced, particulate matter emissions are sharply reduced for butanol contents up to 16% (by volume), whereas NOX emissions are not negatively affected. Butanol-diesel blends could be introduced without startability problems up to 13% (by volume) butanol content at a cold ambient temperature. Therefore, biobutanol can be considered as an interesting option to be blended with diesel fuel, contributing to the decarbonization of these sectors.
... Butanol molecules contain alkyl and hydroxyl, that easier to blended into diesel fuel. In fact, butanol has very good intersolubility with diesel fuel without any surfactant [7].The Butanol have four isomers. Each type of isomer has distinct physical and chemical characteristics. ...
... Tert-butanol is fully miscible with water. By owing these advantages, butanol-diesel fuel blends studies began to increase in the recent years [3,[7][8][9]. These physical and chemical properties indicates that butanol has the capability to overcome the disadvantage from other types of low-carbon alcohols. ...
Alcohols are important alternative fuel resources for diesel engines. Prominent fuels of the three types include water in diesel reduce engine temperature and NOx and alcohols with a high number of carbons. There is potential to use tertiary blends of diesel fuel, water and higher alcohols, such as butanol, in diesel engines for the purpose of increasing the use of alternative fuel and decreasing fossil fuel consumption. In this study, diesel fuel (D) was mixed with water (5%), and butanol (5% - 10%). Test fuel blends of W5DBu5 (5% of water, 5% of butanol), W5DBu10 (5% of water, 10% of butanol) and W5DBu15 (5% of water, 15% of butanol) were prepared using ultrasonic emulsifier and tested in a diesel engine. It carried engine performance and exhaust emission tests of the blends out on a four-cylinder, four-cycle diesel engine generator at a fixed load of 50% and various engine speeds from 1000 rpm to 3000 rpm. According to engine test results, brake specific fuel consumptions (BSFC) of Blended fuels decrease compared to diesel at all engine speed. As compared to diesel, W5DBu15 presented the best oxides of nitrogen (NOx) at a speed of 2000 rpm with a reduction of 34.7%.
... Investigations into alternative fuels for internal combustion engines (ICEs) have become significant lately due to growing concerns about ecological issues. Extensive research has been conducted on the utilization of bio-butanol as a fuel or blending component in ICEs [4][5][6][7]. However, the extraction and fermentation process of bio-butanol reduces its economic viability. ...
In recent years, biofuels have gained considerable prominence in response to growing concerns about resource scarcity and environmental pollution. Previous investigations have revealed that the appropriate blending of iso-propanol–butanol–ethanol (IBE) into diesel significantly improves both the c combustion efficiency and emission performance of internal combustion engines (ICEs). However, the combustion mechanism of IBE–diesel for the numerical studies of engines has not reached maturity. In this study, a skeletal IBE–diesel multi-component mechanism, comprising 157 species and 603 reactions, was constructed using the decoupling method. It was formulated by amalgamating the reduced fuel-related sub-mechanisms derived from diesel surrogates (n-dodecane, iso-cetane, iso-octane, toluene, and decalin) and n-butanol, along with the detailed core sub-mechanisms of C1, C2, C3, CO, and H2. The constructed mechanism is capable of better matching the physical and chemical properties of actual diesel fuel. Extensive validation, including ignition delay, laminar flame speed, a premixed flame species profile, and engine experimental data, confirms the reliability of the mechanism in engine numerical studies. Subsequent investigations reveal that as the IBE blend ratio and EGR rate increase, the ignition delay exhibits an increase, while the combustion duration experiences a decrease. Blending IBE into diesel, along with a specific EGR rate, proves effective in simultaneously reducing NOx and soot emissions.
... However, blending biodiesel with alcohol has its own drawbacks. Many research studies have noted that the main issues associated with adding alcohols to biodiesel are their poor miscibility and their instability in the mixture, which depend on many factors such as their blending ratio, the temperature and the time before the separation of the phases, etc. [21,22] The use of ethanol in diesel engines as a blending fuel has several disadvantages. Thus, its low cetane number and calorific value influence the characteristics of the mixture. ...
This research work investigates the effects of adding ethanol to biodiesel-diesel blends on the performance and emissions of a single-cylinder, four-stroke, air-cooled compression-ignition engine. The engine was half loaded within a speed range 1000-2500 rpm. Four different fuel blends are considered: B0 (no biodiesel or ethanol), B10 (10% biodiesel), B10E2.5 (10% biodiesel with 2.5% ethanol), and B10E5 (10% biodiesel with 5% ethanol). The findings show that adding biodiesel slightly affects the engine power at low and medium speeds but increases power by approximately 6% at high speeds. Ethanol addition has a more significant impact, with an increase in engine power of 16% at 1700 rpm and 13% at 2500 rpm for 2.5% and 5% ethanol blends, respectively. All blends show an increase in brake mean effective pressure (BMEP) compared to B0, with the maximum enhancement observed in B10 with an average increase of 13% across all speeds. Specific fuel consumption is reduced with both biodiesel and ethanol addition, with a slight advantage for biodiesel, particularly at low and medium speeds. Thermal efficiency shows a reverse behaviour, with a small negative impact of ethanol addition. Biodiesel addition significantly increases carbon monoxide (CO) emissions, reaching an average of 190% across all speeds. However, adding ethanol helps mitigate this increase, especially at low and medium speeds, with an average decrease of 32% for 2.5% ethanol blend compared to B0. Carbon dioxide (CO2) and nitrogen oxides (NOx) emissions are reduced with biodiesel addition, and further reduced with ethanol addition. Overall, CO2 and NOx emissions are reduced with both biodiesel and ethanol addition.
... where dQ n dθ is the net heat release rate (J/°CA), P is the instantaneous cylinder pressure (N/m 2 ), V is the instantaneous cylinder volume (m 3 ), θ is the crank angle (degree) and γ is the ratio of specific heats C p /C v (kJ/kg·K). γ depends on temperature and influences the intensity of dQ n dθ andQ lw .Q lw is the blow by losses which are evaluated by Rakopoulos et al. (2011). The gross heat release rate can be calculated by Equation (5). ...
... Lower BTE was found for entire range of fuel combinations as compared to conventional diesel. Cooling effect [28] and lower cetane number [29] of n-butanol along with poor utilization of biogas [30] were the reasons for reduced BTE. ...
... In comparison to biodiesel, butanol has a higher oxygen concentration, which further reduces soot. Because NOx emissions have a higher heat of evaporation than other gases, they can also be lowered by lowering the combustion temperature [117]. Usually, as the number of carbon atoms in alcohol increases, so does its low heating value. ...
The rate of increase in greenhouse gas concentrations in the atmosphere has already reached a critical point. Day by day, the number of vehicles on the road is increasing in a geometric progression, which has led to an increase in carbon monoxide and hydrocarbon emissions from spark-ignition engines. In this review, the formation of engine emissions and their effects on environmental and human aspects are discussed in detail. This review clearly discusses how fuel properties affect engine performance and reduce emissions. This paper is a review of the use of various types of oxygenates with gasoline on engine emissions and the improvement of the performance of engine combustion by oxygen enhancement. The various oxygenates (methanol, ethanol, ethyl tert butyl ether, methyl tert butyl ether, butanol, dimethyl carbonate, dimethyl ether, and diisopropyl ether) are reviewd in this paper based on their production and the feasibility of adding them to fossil fuels. The study found that fuel volatility, oxygen percentage, and octane number are the desired properties to use as oxygenates in gasoline. Among different oxygenates, DIPE would be a suitable oxygenate additive to gasoline based on its blending properties, and performance, emission, and combustion behaviour of gasoline-DIPE blends.
... The biodiesel is defined by ASTM as "A fuel comprised mono -alkyl esters of long-chain fatty acids derived from vegetable oils or animal fats'' [5]. Biodiesel can be used directly as a substitute fuel in a Diesel engine or blended in various percentages with fossil Diesel [6]. Biodiesel has various characteristics that make it an excellent alternative fuel for engines, and the most notable advantages of utilizing biodiesel over Diesel fuel are its low aromatics, biodegradable, low Sulphur, nontoxic, and the oxygen-containing molecules' existence, which suppress the emissions of the Sulphur dioxide generation, HC, and CO through the procedure of combustion. ...
... However, the use of fuels such as ethanol and methanol in internal combustion engines requires some engine modifications [33,34]. By using alcohol with high carbon numbers (butanol and pentanol), high thermal efficiency can be achieved in CI engines without any engine modification [32,35,36]. ...
In this study, effects of multi-walled carbon nanotube (MWCNT) addition to waste frying oil biodiesel (B20) on performance, combustion, and exhaust emissions in a direct-injection compression ignition engine were investigated. Experiments were carried out at maximum engine torque speed and four different engine loads. The results show that engine performance has deteriorated somewhat by using B20 fuel without MWCNT additive compared with neat diesel. The addition of MWCNT to B20 improved fuel properties. This occurred because MWCNT additive improved engine performance. By using 100 ppm additive to B20 fuel, the combustion duration has been shortened compared to neat diesel, indicating that thermal efficiency has increased with the decrease of heat losses. The highest indicated thermal efficiency was recorded as 33.16% at 15 Nm engine load using 100 ppm additive to B20 test fuel. Also, 100 ppm additive to B20 test fuel reduced hydrocarbon, CO and soot emissions by 41, 36.4 and 31.8%, respectively, compared to reference neat diesel fuel. The MWCNT additive improved the in-cylinder combustion reactions, thereby increasing engine performance. With the improvement of combustion, in-cylinder gas temperatures increased. For this reason, higher NOx emissions were obtained using MWCNT additive fuels compared to neat diesel.
... The BTEs seen for various liquid fuel blends (like anhydrous n-butanol-based diesohol) were also better than that for diesel in previous studies. [31][32][33] ...
A batch microwave‐assisted biodiesel (MWBD) conversion system was scaled up to using two magnetrons, giving a total of 2000 W microwave (MW) power, with the magnetrons placed asymmetrically on opposite sides of the MW cavity. This system was used to produce methyl ester from palm fatty acid distillate (PFAD). The response surface method with a Box–Behnken experimental design was applied to find the optimal point giving the maximum percentage free fatty acid (FFA) conversion at the minimum cost (USD). At this point the molar ratio PFAD:MeOH was 1:9; the temperature was 80 °C; and time was 20 min. Regression models predicted the %FFA conversion and the cost (USD) with coefficients of determination (R²) of 0.9519 and 0.8654, respectively. Simulations were conducted with the finite element method, and the temperature profiles from the simulations fitted the experimental data well. Finally, the fuel properties of the MWBD were analyzed and compared with Thai agricultural engine diesel and high‐speed diesel standards, and the standards were met. The MWBD, the liquid fuel blend (LFB with MWBD:CHSD 50:50 by volume), and a commercial high‐speed diesel (CHSD) were tested in a diesel engine over the 1.28–5.09 kW power range at a fixed 2200 rpm speed. All the fuels performed similarly and without any problems in the test runs. © 2022 Society of Chemical Industry and John Wiley & Sons, Ltd.
... In light of these factors, the use of ethanol in a mixture with mineral Diesel oil, without the additives to ensure homogenization and stability, can affect the functioning and durability of the engine, besides limiting the percentage of the mixture. Hence, from the perspective of engine durability and safety, emulsifying additives and co-solvents have been used, in addition to Diesel oil mixtures containing up to 15% of ethanol (lAPUERTA; ARMAS; GARCÍA-COnTRERAS, 2007;RAKOPOUlOS, et al., 2011;SATHIYAMOORTHI;SAnKARAnARAYAnAn, 2017;YIlMAZ et al., 2014). From the various researches conducted, it appears that the incorporation of biodiesel with the mineral Diesel oil enhances the solubility with ethanol (KWAnCHAREOn et al., 2007). ...
Partial fuel replacement strategies arising from fossil sources used in compression ignition engines involve mixtures of mineral Diesel oil, biodiesel and ethanol to minimize the gas emissions. In this study, experimental assessments were performed on a multi-cylinder, turbocharged aftercooler, compression-ignition, agricultural tractor engine provided with electronic injection management and an exhaust gas recirculation (EGR) gas treatment system. Diesel oil containing low (BS10 -10 ppm) and high sulfur concentrations (BS500 - 500 ppm) was utilized, with 10% of biodiesel as a constituent established by Brazilian legislation, in blends with 5, 10, 15 and 20% of the total volume, made up of anhydrous ethanol with additives. Thus, there were eight fuels blends and two reference conditions (without ethanol). The emissions of CO, HC, NOx and the HC+NOx gases were estimated, corresponding to the eight operating modes (M) of the ABNT NBR ISO 8178-4 standard. From the findings, it was evident that with the rise in the ethanol concentrations in the fuel blends there was a corresponding increasing in the CO, NOx and HC+NOx emissions. The HC, on the contrary, exhibited a pattern of higher emissions for the high-sulfur fuels (BS500) at low loads. No difference was observed for the NOx emissions at high loads. In the other operation modes, different behaviors were expressed for the BS10, which sometimes showed an increase, while at other times a reduction in the NOx emissions. Regarding the BS500, the NOx emission increased when the ethanol concentrations rose. As the specific emissions of the NOx were higher than those of the HC (in g.kW-1.h-1), the behavior exhibited by the HC+NOx showed similarity to that of the NOx. When the directly analysis of the operating modes was taken into consideration, the use of ethanol triggered an upswing in the emissions, exceeding the threshold of MAR-1 and EURO V standards.
... where η is the combustion efficiency, as for diesel it takes a value of 0.776 (Yi et al., 2006); ṁ is the instant mass loss rate of fuel, g/s; and ΔH is the heat of fuel combustion, kJ/g, taking 42.5 kJ/g for diesel (Rakopoulos et al., 2011). ...
Firefighting by sealing the cabin is often served as a final-taken and efficient means of suppressing ship fire. When a fire occurs in a closed engine room, it could cause the internal pressure increased and the oxygen concentration decreased, which further affects the fire burning processes. The interaction between the combustion processes and the changing environment makes sealed fires even complicated. This study investigates the behaviors of smoke plume entrainment and filling in a sealed ship engine room. Theoretical models regarding the plume entrainment and smoke filling are developed, respectively. A new reverse analysis method by coupling particle swarm optimization (PSO) with the smoke filling model is proposed to determine the unknowns in the plume entrainment model. Based on the experimental data in the literature and the reverse analysis, the explicit smoke filling model of sealed ship engine room is developed. Several previous experimental measurements and numeric simulations are used to validate its prediction ability. The results also suggest that a sealed fire has a higher smoke entrainment level than an open case. The proposed sealed ship engine room fire model can be applied to the engineering safety design of cases with potential sealed fires.
... (2)[37] Auto-ignition is driven by the unique chemical kinetics of the fuel in the cylinder, and the rate of combustion is jointly controlled by the thermodynamic conditions within the cylinder and the chemical nature of the fuel of the reaction mixture [38]. In a diesel engine, the reaction mixture fuel must be combusted with a small amount of residual fuel remaining from the previous combustion reaction and a product formed after combustion.Shui Yu et al. [59] A number of studies were conducted, mainly for experiments involving the combustion of n-butanol and diesel mixed fuels in HCCI engines. The experimental results found and demonstrated that the simultaneous generation of NOx and soot emissions can be effectively reduced to ultra-low levels. ...
The consumption of non-renewable fuel sources (fossil fuels, etc.) in the natural environment is a large amount of exhaust gas emissions that can be generated after combustion of fuel in internal combustion engines. Due to this severe environmental problem, researchers have studied the alternative energy of engines. A new interest has emerged. Biodiesel has been recognized as one of the most promising renewable energy sources in the world in recent decades. Therefore, research has been conducted to increase the biodiesel-diesel mixture in which 10% n-butanol (volume) is added, which is generally considered to be an oxygen-containing additive. However, the addition of n-butanol does not meet engine emissions, so we can consider adding a butanol-acetone mixture as an additive to the engine to improve engine combustion performance and exhaust emissions.
... In addition to suitable fuel properties, it has also been shown that the use of these alcohol blends can suppress soot formation (problem of pure diesel fuel) without significantly increasing NO x emissions (problem of FAME), eliminating the smoke-NO x trade-off [45][46][47]. Ethanol-diesel fuel blends are commonly used in some countries, sold under commercial names, such as E-diesel (containing about 7-15% ethanol), or O2Diesel™ (consisting of 7.7% vol. ethanol), among others [60]. ...
In this paper, the fuel properties of mixtures of diesel fuel and ethanol and diesel fuel and butanol in the ratio of 2.5% to 30% were investigated. The physicochemical properties of the blends such as the cetane number, cetane index, density, flash point, kinematic viscosity, lubricity, CFPP, and distillation characteristics were measured, and the effect on fuel properties was evaluated. These properties were compared with the current EN 590+A1 standard to evaluate the suitability of the blends for use in unmodified engines. The alcohols were found to be a suitable bio-component diesel fuel additive. For most physicochemical properties, butanol was found to have more suitable properties than ethanol when used in diesel engines. The results show that for some properties, a butanol–diesel fuel mixture can be mixed up to a ratio of 15%. Other properties would meet the standard by a suitable choice of base diesel.
... Viscosity is an important property of fuels used for diesel engine [1,2]; it is related to fluid flow process and affects the fuel injection into the combustion chamber and the atomization quality [3][4][5], influencing fuel combustion and affecting engine's efficiency and harmful gases emission [6,7]. ...
Viscosity is an important property of fuels used for diesel engine affecting engine’s efficiency and harmful gases emission. Viscosity of liquid fuels depends especially on fuels composition and temperature. The dynamic viscosity of diesel fuel, biodiesel and blends of diesel with biodiesel, i -propanol and n -butanol was measured for temperature ranging from 293.15 K to 323.15 K and atmospheric pressure. It has been verified that well-known Arrhenius derived equations can be used to estimate with good accuracy, viscosity at different temperatures for diesel, biodiesel, diesel+biodiesel blends, but also for diesel blends with propanol and butanol. Values of activation parameters: activation energy, activation enthalpy and activation entropy for the viscous flow were derived based on linearized Eyring’s type equation. The values of the activation energy for viscous flow of fuels and fuels blends calculated based on measured values of dynamic viscosity in the temperature range of 273.15 K and 323.15 K were similar to those presented in the literature for some hydrocarbons, esters, and alcohols, respectively.
... To attain promising circumstances for ignition, ethanol necessitates less heat and inferior intake air temperature as it has low heat of vaporization. Furthermore, its mixtures with biodiesel are to recover solubility and decrease viscidity to support flow ability [20]. Inclusively, ethanol has physical properties near enough to diesel, consequently, ethanol is a significant preservative or substitute fuel for use in CI engines [21]. ...
The current scenario of abating fossil fuels has imposed the experts to discover for a substitute fuel that can be used in diesel engines. At present, scientists and specialists have instigated that biodiesel along with alcohols can be a suitable substitute for the existing situations. This study attempts to utilize ethanol-biodiesel-diesel blend as pilot fuel engine. The engine performance and emissions parameters of dual fuel mode were investigated and related with conventional diesel fuel. It is inferred from the test outcomes that NOx-smoke opacity exhalation were drastically reduced with bi-fuel mode in relation with conventional diesel. The higher HC exhalation level was observed with biogas-diesel with bi-fuel mode than natural diesel. The utilization of oxygenated additives such as ethanol and biodiesel improves the emissions characteristics from diesel engine. However, BTE was noticed to be inferior with bi-fuel mode as compared to diesel mode.
... The trade-off between PM and NO x emission can be improved successfully by blending butanol with diesel/biodiesel in the optimal composition. This trend is similar to the results obtained by Rakopoulos et al. (2011). ...
Biodiesel is substantially found to reduce carbon dioxides, hazardous particulate matter but increasing anthropogenic nitrogen oxides (NOx) emissions. Fuel blending with alcohol oxygenate is one of the best NOx mitigation technologies. The objective of this present study is to develop a model-based product design optimisation of diesel/biodiesel/alcohol blends incorporated with an accurate NOx prediction model as the model's predictive accuracy. The compositions for each fuel blend are deliberately formulated via systematic Linear Programming. The effects of cetane number, oxygen content, and heat of vaporisation have been evaluated. Performance, combustion characteristics, and environmental impact of the fuel blends were compared to diesel standard, which complies with the fuel regulation: ASTM D975 and EN590 standards. The result depicted that 70% diesel, 20% biodiesel, and 10% butanol is the optimal blend with the similar performance (power output) as diesel, lowest cost, and NOx emissions reduction from 7% up to 15%. The increase of oxygen content causes a stronger cooling effect to reduce the NOx pollutant emissions. The NOx formation prediction has been performed by adopting the fuel blend properties, including cetane number, and oxygen content using a rigorous approach. The NOx formation prediction has been performed by adopting the fuel blend properties, including cetane number and oxygen content, using a rigorous approach. The final NOx prediction models developed can be a precursor to implementing the physical system in a dynamic testing phase. Higher alcohol (butanol) offers superior characteristics such as higher HOV (stronger cooling effect to reduce NOx formation), CV (higher power output), CN (reduces ignition delay), density and viscosity (better fuel flow for better atomisation), and flash point (for safer storage and handling) as compared to lower alcohol like ethanol. Conclusively, diesel/biodiesel/butanol enhances the HOV, which leads to a stronger cooling effect in the combustion chamber, thus reducing NOx formation.
... Figures additionally show that the NOx emanations declined (roughly 17%) with a higher level of ethanol in the fuel blend in concurrence with the consequences of different papers [28]. This conduct could be because of lower temperatures conditions during the ignition of the mixes included ethanol because of lower cetane number, calorific worth, and adiabatic fire temperature of ethanol and its higher dormant warmth. ...
The crucial justification this examination article is to break down the combined effects of biodiesel-ethanol fuel blends on the display and surge ascribes of a diesel engine by the Response Surface Methodology. Considering the results, the brake power and power were lessened by around29% with growing the proportion of ethanol in the fuel mix. Maybe then, the BSFC of fuel blends improved around 15% in with a more elevated level of ethanol in light of the lesser calorific assessment of ethanol related with biodiesel. Regardless, higher thickness and thickness of biodiesel premise extra fuel implantation; so there is no perceptible change in BSFC regards for all blends. About spread limits, the more degree of ethanol achieved less proportion of smoke level and NOx release around 38% and 17%, independently in view of the incredible level of oxygen in the nuclear development of ethanol. Regardless, there is an around 44% diminishing in CO outpourings for a significant degree of biodiesel contained blends. As shown by the GA smoothing out, the results showed that the biodiesel rate in the fuel mix, RPM, and engine trouble were joined to 94.65%, 2800, and 65.75%, in a particular request as the ideal conditions. It is assumed that ethanol is more suitable to improve the spread ascribes than that of the introduction characteristics.
... They found that alcohol/diesel blends increase the ignition delay (ID), peak in-cylinder pressure and heat release rate (HRR), and reduce the smoke and CO emissions in comparison with diesel fuel operation. Rakopoulos et al. 16,17 examined the influence of the addition of butanol in diesel fuel (by volume 8%-24%) on the characteristics of a CI engine. Their results indicated that with the use of B/D blends, the peak in-cylinder pressure, HRR and UBHC increased, while the CO, soot, and NOx emissions decreased. ...
The rapid consumption of fossil fuels, ever rising energy demand, and rigorous emission norms have been attracting the attention of researchers toward clean renewable fuels such as alcohol‐based fuels. Higher chain alcohol fuels are attractive alternative fuels for use in diesel engine. A higher chain alcohol (butanol, pentanol, etc.,) has better blending properties, higher calorific value, and higher cetane number than the lower chain alcohol. Alcohol fuels can be produced from the biomass. Therefore, it is important to examine the fuel, as well as its blends with diesel fuel in diesel engine for the engine characteristics. The present paper aims at studying the performance characteristics of a DI‐CI engine using butanol/diesel (B/D) blends with and without exhaust gas recirculation (EGR). Experiments were performed on a single cylinder CI engine with two different B/D blends (20% and 40% by volume of butanol in the mixture—denoted as a Bu20 and Bu40), with different EGR rates (0%–30% in steps of 10%). The experimental results showed that the brake thermal efficiency (BTE) improved by 1.1% and 1.25% for Bu20 and Bu40 blends in comparison with Bu00. Nitrogen oxides (NOx) emissions reduced by 7.9%, 12.9% for Bu20 and Bu40 blends compared Bu00 respectively. Similarly, the soot emission decreased by 18% and 40.9% for Bu20 and Bu40 compared to Bu00. With the use of EGR, the NOx emissions significantly decreased. At 30% of EGR rate, the NOx emission reduced by 53.9%, 60.2%, and 67% for Bu00, Bu20, and Bu40, respectively. The soot emissions increased slightly at lower EGR rates of 0% to 20%. However, the soot emissions increased drastically at higher EGR rates for all the B/D blends. It is concluded that a combination of higher fraction of B/D blends along with a small EGR rate, can achieve lower emissions (soot and NOx) with a small penalty on the engine performance.
... Aiming at the investigation of oxygenated fuels applied to diesel engine, Rakopoulos et al. [8][9][10] have investigated the influence on emission and performance of ethanol and n-butanol in a diesel engine. The results show that the diesel blending with oxygenated fuels in diesel can decrease the soot emission significantly, and with oxygenated fuels proportion increase, the soot emission further decrease. ...
Pine oil has a high calorific value, which makes it an appropriate biofuel for diesel engines. In this paper, spray characteristics such as spray morphology, spray penetration and spray cone angle of pine oil-diesel blends were investigated under various injection pressures using a constant volume spray chamber. The effects of the injection pressure on the combustion and emission characteristics of pine oil-diesel blends were experimentally investigated in a four-cylinder diesel engine under medium EGR (24.6%). Four different fuels including pure diesel (P0), three blends of pine oil and diesel fuel denoted as P20 (20% pine oil and 80% diesel in volume), P40 (40% pine oil and 60% diesel in volume), and P50 (50% pine oil and 50% diesel in volume) were tested. Our results indicate that, as the injection pressure increases, the spray penetration of blended fuels increase, while the spray cone angle shows slightly change. And with the increasing of injection pressure, the peak values of heat release rate and in-cylinder pressure during the combustion of the four blended fuels increase, the BSFC slightly increase, the emissions of soot, CO and THC decrease, however NOx emissions increase. The effects of the increase of injection pressure on soot emissions of pure diesel are greater than that of blended fuels. When the mixing ratio of pine oil exceeds 40%, the beneficial effects of injection pressure on soot emissions from the combustion of blended fuels are weakened. At the same injection pressure, the BSFC of P20 almost equals the value of P0. As the mixing ratio of pine oil increases, the spray penetration and the spray cone angle of blended fuels increase, which enhanced the atomization process and fuel evaporation. With the increase ratio of pine oil, the peak values of in-cylinder pressure and heat release rate increase, the emissions of NOx, CO and THC increase and soot emissions decrease dramatically. For the combustion of the tested fuels, the number concentration and mass concentration of total PMs can be reduced by increasing the injection pressure or the amount of pine oil in the blends. At an injection pressure of 100 MPa, the total PM number concentration and mass concentration of P50 are respectively lower 86.30% and 96.55% than the values for pure diesel.
... Aiming at the investigation of oxygenated fuels applied to diesel engine, Rakopoulos et al. [8][9][10] have investigated the influence on emission and performance of ethanol and n-butanol in a diesel engine. The results show that the diesel blending with oxygenated fuels in diesel can decrease the soot emission significantly, and with oxygenated fuels proportion increase, the soot emission further decrease. ...
The high level of emissions and pollution caused by diesel engines increases the importance of developing low-emission and high-efficiency fuel technologies. Implementing various modifications in engines has the potential to reduce emissions, however, these adjustments can lead to technical difficulties and inefficiencies in terms of cost. In this case, as an alternative solution, the use of diesel fuel (DF), biodiesel (B100), nanoparticle and light or heavy alcohol mixtures can be considered; these fuels can help engines produce less polluting emissions. As it is known, the main reason why internal combustion engines emit emissions such as particulate matter, hydrocarbon (HC), and carbon monoxide (CO) into the atmosphere is incomplete combustion of the fuel. The high oxygen content of fuels such as biodiesel and alcohol can solve these combustion problems. The focus of this study is a detailed investigation of the effect on emissions of mixtures of DF, B100 derived from safflower seed oil with a low Free Fatty Acid (%FFAs) value, and n-decanol. Emission values obtained for DF, B100, 50%/50% volume ratio diesel/biodiesel (DF50B50), 50%/50% volume ratio diesel/n-decanol (DF50DE50), 50%/25%/25% volume ratio diesel/biodiesel/n-decanol (DF50B25DE25), Emission values of 50%/35%/15% diesel/biodiesel/n-decanol (DF50B35DE15) and 50%/45%/5% diesel/biodiesel/n-decanol (DF50B45DE5) blends were compared. Among these blends, compared to DF at maximum load, DF50B50, DF50DE50, DF50B25DE25, DF50B35DE15, and DF50B45DE5 fuels reduced smoke opacity (SO) by 80.17%, 86.78%, 54.55%, 21.49%, and increased it by 15.70%, respectively. Under the same load conditions, compared to DF, NOx emissions were reduced by 19.18%, 21.38%, 17.30%, increased by 34.91%, and reduced by 15.72% respectively with DF50B50, DF50DE50, DF50B25DE25, DF50B35DE15, and DF50B45DE5 fuels. Under the same load conditions, CO emissions were also reduced by 23.08%, 15.38%, 16.15%, increased by 40%, and reduced by 16.92% respectively with DF50B50, DF50DE50, DF50B25DE25, DF50B35DE15, and DF50B45DE5 fuels.
The rapid increase in global warming, limited availability of fossil fuel reserves, and their non-renewable nature have heightened interest in alternative biofuels. Alternative fuels such as biodiesel, vegetable oils and bio alcohols derived from other biomass sources play an important role in fossil fuel substitution. Moreover, oxygenated compounds such as ethers, alcohols, and esters enhance the complete combustion of fuels, increasing efficiency. Due to their high octane/cetane values and desired properties, they stand out as suitable additive fuels. Since these biofuels belong to the aliphatic alcohol class, they do not contain aromatic compounds (benzene and its derivatives). This offers potential additional advantages in reducing emissions of soot, particulate matter, and toxic substances, including polycyclic aromatic hydrocarbons (PAHs). By making various modifications to internal combustion engines, the emissions released into the atmosphere from compression-ignition engines can be reduced to a minimum level. However, these modifications may involve technical and economic challenges. However, the use of diesel fuel (DF), biodiesel (B100), and light or heavy alcohol blends can help engines emit fewer pollutants. The preference for these alternative fuels holds the potential to reduce environmental impacts and offer a sustainable solution. In this study, the effects of DF, B100 synthesized from safflower seed oil, and n-octanol blends on emissions have been investigated. Emission values obtained for DF, B100, 50%/50% volume ratio diesel/biodiesel (DF50B50), 50%/50% volume ratio diesel/n-octanol (D50OC50), 50%/25%/25% volume ratio diesel/biodiesel/n-octanol (DF50B25OC25), Emission values of 50%/35%/15% diesel/biodiesel/n-octanol (DF50B35OC15) and 50%/45%/5% diesel/biodiesel/n-octanol (DF50B45OC5) blends were compared. Among these blends, DF50B50, DF50OC50, DF50B25OC25, DF50B35OC15, and DF50B45OC5 fuels reduced the smoke opacity (SO) by 80.17% and 85.12%, 61.16%, 23.97%, and 21.49% compared to DF, respectively, at maximum load. Under the same load conditions, DF50B50, DF50OC50, DF50B25OC25, DF50B35OC15 and DF50B45OC5 fuels reduced nitrogen oxides (NOx) emissions by 19.18%, 1.89% and 18.87%, increased them by 22.01% and reduced them by 5.97% respectively compared to DF. DF50B50, DF50OC50, DF50B25OC25, DF50B35OC15 and DF50B45OC5 fuels reduced CO emissions by 23.08%, increased 6.15%, decreased 17.69%, increased by 12.31% and decreased by 9.23%, respectively, under the same load conditions.
Various modifications can be made to diesel engines to reduce emissions caused by them. However, these modifications may pose technical challenges and may not be cost-effective. Instead, using diesel fuel (DF), biodiesel (B100), and light or heavy alcohol blends in engines can help reduce the emission of pollutants. For this reason/reasons, the effects of DF, B100 synthesized from safflower seed oil, and n-hexanol blends on emissions have been investigated in this study. Emission values obtained, DF, B100, 50%/50% vol% diesel/biodiesel (DF50B50), 50%/50% vol% diesel/n-hexanol (DF50HE50), 50%/25%/25% vol% diesel /biodiesel/n-hexanol (DF50B25HE25), 50%/35%/15% vol diesel/biodiesel/ n-hexanol (DF50B35HE15), and 50%/45%/5% vol diesel/biodiesel/n-hexanol (DF50B45HE5) ) were compared with the emission values of the mixtures. Among these blends, DF50B50, DF50HE50, and DF50B25HE25 fuels reduced smoke opacity (SO) by %80.17, %88.43, and %56.20, respectively, compared to DF at full load. Under the same load conditions, DF50B50, DF50HE50 and DF50B25HE25 fuels reduced NOx emissions by 19.18%, 2.20% and 20.44%, respectively, compared to DF, while CO emissions decreased by 23.08%, increased by 3.85% and decreased by 17.69%, respectively, under the same load conditions.
The rapid increase in global warming and the approaching depletion of fossil fuel reserves are steadily increasing the interest in alternative biofuels. Biodiesel, along with heavy and light alcohols and other biomass sources, such as bioalcohols derived from various biomass sources and vegetable oils, plays a significant role as alternative fuels. Ethers, alcohols, and esters, which are oxygenated compounds, enhance the efficiency of fuels by promoting complete combustion and exhibiting high octane/cetane values. Due to these desired properties, they stand out as suitable fuel additives. Additionally, biodiesel and alcohols belong to the class of aliphatic alcohols, which means they do not contain aromatic compounds (such as benzene and its derivatives) in their chemical structures. This offers potential additional advantages in reducing emissions of soot, particles, and toxic substances, including polycyclic aromatic hydrocarbons (PAHs). In this study, the effects of mixtures of DF, B100, and n-pentanol on emissions were investigated. The pure and blended fuels investigated in emission studies are as follows: Pure DF and pure B100, 50%/50% volume ratio diesel/biodiesel (DF50B50), 50%/50% volume ratio diesel/n-pentanol (DF50PE50), 50%/25%/25% volume ratio diesel/biodiesel/n- pentanol (DF50B25PE25), 50%/35%/15% volume ratio diesel/biodiesel/n-pentanol (DF50B35PE15), and 50%/45%/5% volume ratio diesel/biodiesel/n-pentanol (D50B45PE5). The fuels DF50B50, DF50PE50, and DF50B25PE25 reduced the smoke opacity (SO) by 80.17%, 96.69%, and 61.98%, respectively, compared to pure DF under maximum load conditions. Under the same load conditions, DF50B50, DF50PE50, and DF50B25PE25 also decreased NOx emissions by 19.18%, 32.08%, and 14.15% compared to DF, while reducing CO emissions by 23.08%, 33.85%, and 6.92%, respectively. These results indicate that the mentioned fuel blends have significantly improved the reduction of smoke opacity and emissions of nitrogen oxides (NOx) and carbon monoxide (CO) when compared to pure DF at maximum load conditions.
In this study, the %FFAs (Free Fatty Acids) value of the oil was found to be 1.579 mg KOH/g in terms of oleic acid, using the titration method, before the synthesis of safflower seed oil into biodiesel. Since this value is less than 3, it was synthesized into biodiesel with one-step base-catalyzed transesterification reaction. Various fuel properties of the biodiesel were determined using ASTM and EN standard methods, and accordingly discussed. The biodiesel synthesized from safflower seed oil meets both ASTM-D6751 and EN-14214 standards. The blending of alternative biofuels such as biodiesel (B100) and n-butanol into fossil diesel fuels (DF) at certain ratios in recent years, with the aim of controlling emissions such as nitrogen oxides (NOx), carbon monoxide (CO), and smoke, has drawn significant attention. Additionally, since biodiesel and alcohols fall into the aliphatic alcohol category and do not contain aromatic compounds (such as benzene and its derivatives) in their chemical structures, they offer potential additional advantages in reducing soot, particle, and toxic emissions, including polycyclic aromatic hydrocarbons (PAHs). However, studies in the literature have generally only been conducted with relatively low blend ratios (less than 20%). In this study, the effects on emissions of mixtures of DF, B100, and n-butanol were investigated. The emission values obtained were compared with the emission values of DF, B100, 50%/50% volume ratio diesel/biodiesel (DF50B50), 50%/50% volume ratio diesel/n-butanol (D50BU50), 50%/25%/25% volume ratio diesel/biodiesel/n-butanol (D50B25BU25), 50%/35%/15% volume ratio diesel/biodiesel/n-butanol (D50B35BU15), and 50%/45%/5% volume ratio diesel/biodiesel/n-butanol (D50B45BU5) blends. Among these blends, DF50B50 and DF50B25BU25 fuels reduced the smoke opacity (SO) by 80.17% and 72.73%, respectively, compared to pure DF under maximum load conditions. Under the same load conditions, DF50B50 and DF50B25BU25 fuels also reduced NOx emissions by 19.18% and 22.64%, respectively, compared to pure DF, while reducing CO emissions by 30% and 18.46%, respectively.
To investigate the feasibility of diesel engines with high butanol substitution rate (BSR), the performance and emissions of diesel–butanol dual fuel engines are studied numerically. It i based on a four-cylinder diesel engine, which is modified into a diesel–butanol dual fuel engine with port-injected butanol fuel and direct-injected diesel fuel. The simulation is performed using GT-Power software, and simulation results are validated with the experimental data. The engine speeds are set at 1600, 2300, and 3600 rpm, respectively. The engine load is set at 25%, 50%, and 75% engine load, respectively. The BSR varies from 0% to 80% with an interval of 10%. The results show that, with the increase of BSR, the peak cylinder pressure (PCP), and the maximum pressure rise rate (MPRR) decrease, while the brake mean effective pressure (BMEP) and the indicated thermal efficiency (ITE) increase under various working conditions. Among them, the MPRR increases by 9%–12%, while the ITE increases by 6%–7%. In terms of emissions, the nitrogen oxide (NOX) decreases obviously (decrease by 32%–54%), while the carbon monoxide (CO) and the hydrocarbons (HC) decrease slightly (CO: decrease by 4%–10%, HC decrease by 3%–4%).
This study aims to characterize the effect of oxygenated biofuels in diesel engine combustion, thermal efficiency, and emission by blending different percentages of ethanol and biodiesel with fossil fuel derived diesel. In this research, 5% and 10% by weight of bioethanol were added to commercial B10 (10% biodiesel and 90% diesel), B20 (20% biodiesel and 80% diesel) and B100 (100% biodiesel) and experimented on using a three liter four-cylinder common rail diesel engine. The experiment was performed under three engine speeds of 1000 rpm, 1500 rpm, and 2000 rpm with three constant engine torques of 56 Nm, 84 Nm, and 140 Nm. The results show that ethanol-biodiesel-diesel ternary blended fuels are higher in premixed combustion pressure and net heat release rate (NHRR) peaks. The cumulative heat release of ethanol blended fuels is also higher for ethanol blended fuels. The fuel consumption increased with the ethanol and biodiesel percentage in the blended fuels due to the lower heating value while the brake thermal efficiency did not decrease. It was clearly observed that the particle emission could be reduced by more than 50% when ethanol and biodiesel percentage increased.
This research was directed to reduce the global diesel engine emissions and dependency on finite fossil fuel reserves. The ethanol was blended by weight ratio with commercial “B20” fuel (20% palm oil’s biodiesel and 80% diesel) as B20E5 (95% B20 with 5% ethanol), B20E10 (90% B20 with 10% ethanol) and B20E20 (80% B20 with 20% ethanol). The results of the engine’s performance, combustion, emission, and agglomerate particles size using blended fuels were compared with the results of based commercial B20 fuel. All fuel samples were tested on a four-cylinder direct injection diesel engine at a constant load of 140Nm with engine speeds of 1000RPM, 1500RPM and 2000RPM. When the engine speed increased, the brake-specific fuel consumption decreased, and the brake thermal efficiency increased. The B20E20 shows the highest brake-specific fuel consumption because of the low energy content of the fuel blend and the highest thermal efficiency because of a better combustion process. The ethanol-blended fuels show higher peaks of in-cylinder pressure and heat release rate than the base B20 fuel, with B20E20 as the highest. Ethanol blended fuels have significant advantages in particulate matters reduction, especially in idle engine speed. The blended fuels decreased soot and CO2 emissions and increased NOx emission. The agglomerate particles size distribution was analysed with 100 samples for each fuel by using Scanning Electron Microscopy (SEM) and Image J tools. The average agglomerate particle size of B20, B20E5, B20E10 and B20E20 are 0.253 µm, 0.245 µm, 0.225 µm and 0.187 µm, respectively. As conclusion, adding ethanol to diesel fuel provide strong advantages on soot reduction and higher engine efficiency due to the enrich of fuel oxygen.
In recent years, searching for efficient solutions to improve the emission and performance characteristics of diesel engines is considered as one of the essential and urgent work. Metal nanoparticles with a large surface area and high heat transfer coefficient could provide the impressive additive ability to the fuel reactivity and atomiza-tion. Therefore, the critical role of metal nanoparticles in the support of diesel engine behaviors using biodiesel and diesel is thoroughly evaluated in this current review. Indeed, preparation methods and critical properties of metal nanoparticles and metal nanoparticles-laden fuels are fully introduced. More importantly, the performance, combustion, emission characteristics, and tribology behaviors of diesel engines running on metal nanoparticles-laden biodiesel are compared to diesel fuel in detail. Generally, metal nanoparticles-included biodiesel facilitates the formation of a more homogeneous oxygen-containing mixture of fuel-air, resulting in a more complete combustion process than that of diesel fuel. As a result, the use of biodiesel with the presence of metal nanoparticles is considered as the potential strategy for promoting spay and atomization, enhancing the combustion process, increasing brake thermal efficiency (BTE), reducing toxic emissions (including carbon monoxide (CO), unburnt hydrocarbon (HC), and smoke), and improving tribology characteristics. However, some drawbacks are also indicated, such as increased NOx emission and brake-specific fuel consumption. In addition, it is also concluded that studies on other environmental impacts (such as PM emission), the stable properties of metal nanoparticles, and economic aspects should be made more extensively before commercial applications of metal nanoparticles in the real world.
Commercialization of biofuels as alternative fuels to conventional diesel fuel for application as transport-fuels for diesel engines is fast becoming attainable owing to the merits offered by the inclusion of significant quantities of an alcohol (ethanol) and a member of the “ether” group (dimethyl ether) as additives or property-improvers for biofuels obtained from biomass. These additives are fuels in kind, but have lower viscosities, flash points, flammability etc., hence they infuse some measures of atomization and moderation in the densities and viscosities of biofuels towards ensuring their suitability for use in Internal Combustion Engines (ICEs). Biofuels need be improved in terms of fuel quality such as performance, emission and combustion characteristics to meet market specification. This then informs the need for suitable fuel-modifiers which must be tested for their compatibilities with different biofuel-sources before they are used as fuels in ICEs. The mixing ratio of the added components with the biofuels is also to be given utmost attention as an alcohol such as ethanol and an ether (dimethyl ether), are known for their high volatilities which in turn regulate the BTEs and combustion potentials of the fuels, all aimed at improving the cetane numbers or indices of the blended fuels. Owing to the relative abundance of bioresources as precursors for biofuels relative to other sources of ethers and alcohols, literature has it that some prospective alcohols and ethers have been admixed with biofuels as means of upgrading their properties towards ensuring their high suitability for diesel engines with little or no modifications; this then implies that there might be need to begin to look into reconfiguring some diesel engines in order to abate engine wear, fuel degradation as well as catalyst-poisoning towards ensuring/maintaining high engine-compatibilities with these fuels. Therefore, this chapter is proposed for inclusion in Book 1 “Engine and fuels for future transport”, and its focus will be on the effects of using lone ethanol, dimethyl ether or biofuels as well as their blends for use as future transport fuels.
Effort for reduction of global emission level is currently one of the prime areas of concern for the research community across the globe. Particularly due to more stringent standards of emission control, the prevailing diesel engines are on the verge of losing their permission to operate. Engine fuel modification technologies are reported to improve engine combustion and reduce engine emission levels. The enhancement in liquid fuel using oxygenated additives can be a sustainable and cost effective solution to address the issues of the existing diesel engine emission. Among the existing vehicular fuel improvements technologies, the use of biodiesel, alcohols viz. methanol, ethanol, propanol, butanol, and ethers improves performance as well as emission characteristics of engine significantly. As found in open source, the application of biodiesel-alcohol blended fuels can reduce carbon emission by 50–60% and hence considered as a possible conventional fuel substitution for engine applications. These fuels can be applied either completely or as blends with diesel in diesel engines. Moreover, water emulsification with different blends of biofuels can further restrict the engine emission levels particularly the NOx and smoke emission levels up to 25%. Therefore, the current chapter delivers a critical analysis of the use of oxygenated additives for running diesel engines. The improvements in the physiochemical properties of biodiesel/diesel-alcohol blended fuels and their influence on the engine emission characteristics are discussed in the chapter.
Butanol is a sustainable carbon–neutral fuel that can be derived from a variety of biomass resources. It can be potentially be used as an alternative fuel to blend with diesel to decrease greenhouse gas and pollutant emissions. In this paper, three butanol isomers (n-butanol, tert-butanol, and iso-butanol) are blended with diesel in various volume ratios. The combustion characteristics of butanol isomers are experimentally determined in a constant volume vessel under engine-like conditions. The effects of blend ratio, chamber temperature, and chamber pressure on ignition delay and combustion process are investigated. It is shown that the ignition delay decreases at high temperature and at low butanol blend ratio regardless of the isomer type. The combustion characteristics of butanol/diesel blends differ from neat butanol. Both low temperature heat release (LTHR) and high temperature heat release (HTHR) are observed for the three butanol isomers/diesel blends. Under current operating conditions, the ignition delay of three butanol isomer/diesel blends is ordered according to iso-butanol > n-butanol > tert-butanol. Notwithstanding its higher octane number, tert-butanol/diesel blends show the fastest LTHR and thereafter the shortest ignition delay. This is because of the absence of H atom on the alpha carbon of tert-butanol, which contributes to consumption of OH radicals. Consequently, oxidation of diesel is less suppressed. However, the HTHR of tert-butanol/diesel blends is much slower than that of n-butanol/diesel. At 80% blend ratio, a higher chamber pressure is required to improve the reactivity and ignition. Overall, the low reactivity of butanol is beneficial to be applied in diesel engines to increase the fuel/air mixing time so as to attenuate soot emissions.
Unsustainable energy sources are one of the preeminent supply specks of power generation in the prevailing scenario. The
production and utilization of energy have brought about serious ecological effects all over the globe. Exceptionally unpredictable
fossil fuel expenses are making increasingly more ambiguity for the worldwide economy while simultaneously giving an
ambiguous motivation for putting resources into sustainable power source advancements, which are now accepted as a viable
solution. Biodiesel, higher alcohol, and gaseous fuel are considered to be suitable replacements for dwindling natural resources.
These substitute fuels not only aid in enhancing the engine performance but also cooperate in contracting the injurious tailpipe
emissions. In this review article, a study has been made to evaluate the domination of biodiesel, n-butanol, and biogas on the
performance and emission characteristics of the diesel engine in comparison to fossil diesel. Conclusions of empirical analysis
considering emission and performance characteristics with different permutation and combination are put forwarded to understand the commuted result on various characteristics of the diesel engine. The comprehensive study recommends that the
performance characteristics of the engine degrade with substitute fuels, whereas its emission characteristics are depicted to have
abated.
In recent years, n-butanol produced from waste or lignocellulosic materials has become an attractive and sustainable green energy source for diesel engines because has a clear potential for the partial substitution of fossil-based diesel fuel. This study aims to analyse the effects of different n-butanol/diesel fuel blends on the performance and exhaust emissions of a Euro V heavy-duty diesel engine following the World Harmonised Steady-State Cycle (WHSC), as well as the effect of each mode on the test averaged results. The blends evaluated here were blends of conventional diesel fuel with 5%, 10% and 20% (by volume) n-butanol. Conventional diesel fuel was used as a reference fuel to compare the performance and emission characteristics of the different n-butanol blends. The main findings show that 10% butanol could be considered as a suitable proportion for blending n-butanol/conventional diesel owing to its favourable performance and reduction in particulate emissions, without significant changes in the gaseous emissions of NOX. Mode-by-mode comparative analysis results show improved engine performance with the use of n-butanol in most modes, regardless of speed or load conditions. CO emissions in general increase, despite the incorporation of n-butanol reduces CO emissions under high-load and low-speed conditions. THC emissions increase with n-butanol, being more critical under cold start conditions. The influence of n-butanol on NOX emissions does not have a clear trend, but it is observed that NO2 emissions decrease in all modes with the use of n-butanol blends, mainly in low load modes.
There is a growing interest in using long-chain alcohols, i.e. butanol and pentanol, in the transport sector, as a consequence of their potential production from residual biomass via fermentative processes. There is evidence that incorporation of alcohols to diesel fuel enables to overcome the well-known smoke-NOx trade-off under steady state compression ignition engine operation. Nevertheless, the impact of long-chain alcohols under engine transient conditions is not understood and their behavior under Worldwide Harmonized Light Vehicles Test Procedure (WLTP) cycle has not been reported. This investigation addresses the above-mentioned research gaps by characterization of noise and exhaust emissions (CO, total hydrocarbon content or THC, NOx and particulate matter or PM mass, PM number and PM distribution) of a diesel engine running on ultra-low sulfur diesel (ULSD) fuel and its mixtures with 1-pentanol and 1-butanol under stationary and transient conditions (WLTP).
Transient PM number, mass and size distribution have been monitored using Dekati electrical pressure low impactor ELPI + coupled by Dekati Fine Particle Sampler FPS-4000, whereas transient gaseous emissions have been measured with Horiba Mexa 7100D. Increasing the long-chain alcohol content in fuel blends, significantly reduces PM number and mass for both stationary and WLTP tests, being mainly attributed to oxygen content of 1-butanol and 1-pentanol. Addition of long-chain alcohols causes a decrease of emitted NOx in stationary operation, but the opposite trend was found under WLTP. Noise levels seem to slightly increase with the use of higher alcohol/ULSD fuel mixtures. Overall, it may be concluded that utilization of higher alcohol/ULSD fuel blends appears as a favorable substitute to straight ULSD fuel.
N-Butanol may be considered as the future replacement to ethanol due to its lower latent heat of vaporization, low level of impurities and higher heating value than diesel. These properties motivated researchers to perform the experiments in this field in the search of alternative fuels. In the current work an experimental investigation on single-cylinder four stroke diesel engine charged up with n–Butanol blends and pure diesel were used to predict the performance parameter without modification in the engine. In this experimental investigation, N-Butanol was added to diesel with known percentages to enhance the performance of a diesel engine. The blends of n- Butanol biodiesel and diesel fuel were mixed as in the percentage of 95% diesel with 5% n-Butanol as B5, 90% diesel with 10% n-Butanol as B10, 85% diesel with 15% n-Butanol as B15 and 80% diesel with 20% n-Butanol as B20 respectively. Results showed that when the percentage of the blend of n-butanol blend increased to 20% at 16 kg load then Brake thermal efficiency were increased to 30.33% and Brake specific fuel consumption were deceased 16.7% at 16 kg load simultaneously. The results of the experimental study can be further utilized to carry out a similar investigation with various blends of Biodiesel.
To accurately predict the combustion and emissions characteristics of a diesel engine fueled with n-butanol/diesel blends, a more realistic compact-sized skeletal mechanism with (149 species and 497 reactions) was developed in this study based on the decoupling method. It was generated by integrating the simplified fuel-related sub-mechanisms of n-butanol and diesel surrogates including n-dodecane, iso-cetane, iso-octane, toluene, and decalin. The same detailed core sub-mechanisms of C 2 -C 3 and H 2 /CO/C 1 , in which the formation and oxidation of benzene (A 1 ) and larger polycyclic aromatic hydrocarbon (PAH) up to coronene (A 7 ) of alkanes, aromatics, cycloalkanes and alcohols were used. The PAH formation behavior of individual fuel components in the mechanism were analyzed in detail based on the methods of pathway analysis, rate of production and sensitivity analysis. The mechanism was extensively validated against ignition delay time, laminar flame speed, species profile and three-dimensional engine simulation. The results show that the effects of fuel types on the PAH formation are satisfactorily captured, and the combustion characteristics of n-butanol/diesel blends and each component are reliably reproduced by the current mechanism.
The European Community has set as target in its state members, the use of bio-fuels of at least 2 % by the end of 2005 and 5.75 % by the end of 2010 in the transportation fuels. Each country should produce bio-fuels from local raw materials, which may vary from place to place due to, at least, the different weather conditions and soil quality. Greece is now attempting to conform with the 2003/30 EC directive and to produce bio-diesel using oils available from the current agricultural activities, as well as from cultivations of new oil plants with improved oil production and land utilization. Inside the frame of this attempt, a pilot unit with a capacity of 1 to 2 barrels per day has been constructed and operated with the currently rival vegetable oils for bio-diesel production in Greece. Cottonseed oil, sunflower oil and soybean oil produced in Greece have been converted to bio-diesel in the pilot unit and the products were tested according to EN 14214 standards. Some quantities have been delivered to the Greek refineries for use in conventional trucks and also for mixing with transportation diesel fuel and distribution at petrol stations. Tests were conducted to evaluate the performance and exhaust emission levels of all the above bio-diesels, used as supplements to the Greek road diesel fuel at blend ratios of 10/90 and 20/80 (v/v), in a standard, test bench, fully instrumented, direct injection, high speed experimental diesel engine.
An experimental study is conducted to evaluate the effects of using blends of diesel fuel with n-butanol (normal butanol) up to 24 per cent (by volume), which is a promising fuel that can be produced from biomass (bio-butanol), on the combustion behaviour of a standard, high-speed, direct injection (DI), ‘Hydra’ diesel engine located at the authors’ laboratory. Combustion chamber and fuel injection pressure diagrams are obtained at four different loads using a developed, high-speed, data acquisition, and processing system. A heat release analysis of the experimentally obtained cylinder pressure diagrams is developed and used. Plots of histories in the combustion chamber of the gross heat release rate and other related parameters reveal some interesting features, which shed light on the combustion mechanism when using these blends. These results, combined with the differing physical and chemical properties of the n-butanol against those for the diesel fuel, aid the correct interpretation of the observed engine behaviour performance based on and emissions. Moreover, given the concern for the rather low cetane number of the n-butanol that may promote cyclic (combustion) variability, its strength is also examined as reflected in the pressure indicator diagrams, by analysing for the maximum pressure and its rate, dynamic injection timing and ignition delay, by using stochastic analysis for averages, standard deviations, probability density functions, autocorrelation, power spectra, and cross-correlation coefficients.
IntroductionMolecular StructurePhysical PropertiesChemical PropertiesBiofuel StandardsPerspectiveReferences
A fuel blend containing 30 percent ethanol, diesel fuel and additives was tested in a diesel tractor to determine its effect on engine performance and durability. Uprating the delivery of the fuel injection pump was found to be a practical method of restoring the 11 percent power reduction caused by the lower heat content of the blend. Operation of the tractor under on-farm conditions for alternate 100 hour periods totalling 2000 hours on diesel fuel and on the blend revealed no noticeable deterioration in engine condition related to the blend.
The objectives of this book are to present a fundamental and factual development of the science and engineering underlying the design of combustion engines and turbines, and to synthesize the background of the physics, chemistry, fluid flow, heat transfer and thermodynamics into the discipline of engineering. Considerable introductory material is included, not only on the above mentioned sciences, but also on those aspects of fuels, lubricants, instrumentation, combustion and kinetics which are related to design and to air pollution. The causes and control of air pollution are covered throughout the various topics. Chapters are organized to cover basic engine types and their operation, testing, thermodynamics, combustion, pressure and pressure measurement, idealized cycles and processes, equilibrium charts, fuels, knock and the engine variables, exhaust gas analysis and air pollution, fuel metering, engine characteristics, spark ignition and compression ignition engines, lubrication, and compressors and turbines.
For the operation of diesel engines, n-butanol seems to be more favorable as a substitutive constituent for diesel fuel than the lower alcohols, methanol and ethanol, investigated so far. Based on its chemical and physical properties, similar to those of the diesel fuel, it should be possible to realize an economical engine concept with a single fuel system and without additional auxiliary equipment. As in the case of methanol and ethanol - either as a pure component or in mixtures - there is a high potential regarding the improvement of the exhaust gas quality with n-butanol/diesel fuel mixtures, particularly in view of the smoke value, the particulate emissions and the nitrogen oxides.
The aim of the present study is to clarify how utilization methods of vegetable oils influence engine performance and emissions. In the experiment two types of small single cylinder DI diesel engines were employed: Engine A, equipped with a bowl in the piston, is designed for use in fishing boats. Engine B has a toroidal type combustion chamber and is designed for agricultural use. The experiments used BDF (biodiesel fuel) and rape-seed oil as the base fuel: BDF was emulsified with water and rape-seed oil was blended with several kinds of alcohol. The engine performance and emission characteristics were compared with gas oil operation. The emulsified BDF reduced NOx and smoke emissions significantly although the specific energy consumption (BSEC) increased slightly depending on the engine type and operating conditions. Performance tests also showed that with up to 40% (vol.) alcohol addition, the blended fuels with 1-propanol or 1-butanol in rape-seed oil realize stable combustion similar to gas oil operation. The smoke emissions with alcohol blended fuels were somewhat lower than with gas oil while the BSEC was slightly higher with the alcohols. ç
Traditionally, the study of internal combustion engines has focused on the steady-state performance. However, the daily driving schedule of automotive and truck engines is inherently related to unsteady operation, whereas the most critical conditions encountered by industrial or marine engines are met during transients. Unfortunately, the transient operation of turbocharged diesel engines has been associated with poor driveability, as well as overshoot in particulate and gaseous emissions, making the study and modeling of transient engine operation an important scientific objective. Diesel Engine Transient Operation provides an in-depth discussion of all the complex thermodynamic and dynamic phenomena that are experienced by a diesel engine during load increase, acceleration, cold starting or Transient Cycle. Beginning with the fundamental and most influential turbocharger lag problem, the analysis covers a range of topics, including heat transfer, combustion, air-supply and friction. Diesel Engine Transient Operation presents the most important findings in the field, with special attention paid to the discussion of exhaust emission mechanisms and to the various methods of improving transient response. Moreover, the discussion of the main experimental techniques covers the measurement of exhaust emissions and particle size distribution, which has gained increasing interest in recent years due to stringent regulations imposed by the EU, USA, and Japan. Researchers and students in the field will find this book's comprehensive coverage of the latest research particularly informative, and will also appreciate the authors' analysis of available modeling techniques.
Recently, research and testing of oxygenated diesel fuels has increased, particularly in the area of exhaust emissions. Included among the oxygenated diesel fuels are blends of diesel fuel with ethanol, or E diesel fuels. Exhaust emissions testing of E diesel fuel has been conducted by a variety of test laboratories under various conditions of engine type and operating conditions. This work reviews the existing public data from previous exhaust emissions testing on E diesel fuel and includes new testing performed in engines of varied design. Emissions data compares E diesel fuel with normal diesel fuel under conditions of different engine speeds, different engine loads and different engine designs. Variations in performance under these various conditions are observed and discussed with some potential explanations suggested.
This investigation reports engine performance, combustion characteristics, and exhaust emissions with alternative diesel fuels of blends of vegetable oil and various fuel additives (fuel improving agents). To improve the oil viscosity and distillation characteristics, the study used liquid oxygenated agents with lower boiling points and higher volatility than gas oil. The experiments used rapeseed oil and eight kinds of oxygenates: ethanol, 1-propanol, 1-butanol, 1-pentanol, 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, and dibutyl ether. An ordinary small single cylinder DI diesel engine was used and the blending ratio was defined as the volume %; the proportion of oxygenate in the fuel was from 0% (neat rapeseed oil) to 29 or 33%. The results showed that all of the above oxygenates except ethanol and 2-methoxyethanol had good solubility in rapeseed oil (by manual mixing) at room temperature. Compared with gas oil as the standard fuel, the blended fuels including oxygenates with ether chains showed similar specific energy consumption (BSEC) at high loads, while the BSEC was 2-5% higher at low loads. The smoke emissions with the ether oxygenates blended in the rapeseed oil decreased linearly with increases in the oxygen content of the fuel. Performance tests also showed that with up to 33% (vol.) of oxygenate addition, the blended fuels with 2-ethoxyethanol, 2-butoxyethanol, or dibutyl ether realize stable combustion similar to gas oil operation.
Fuel properties essential to the proper operation of a diesel engine were studied for several ethanol-diesel fuel blends. A blend of 10 percent ethanol and 90 percent No. 2 diesel exceeded American Society for Testing and Materials minimum specifications and was given the name diesohol. In engine tests, diesohol gave lower efficiency than No. 2 diesel fuel but also reduced exhaust smoke. A three-cyclinder diesel engine with a distributor-type injector pump was used for the engine tests. The fuels used were No. 1 diesel fuel, No. 2 diesel fuel, and diesohol. Load, speed, fuel flow rate, exhaust smoke, exhaust temperature, and engine-coolant temperature were measured and recorded during the tests. Refs.
Many studies of diesel engine operation by vegetable oils have been carried out as vegetable oils are renewable and offer reductions in carbon dioxide emissions. This paper investigates gas oil blended with rapeseed oil as a diesel fuel substitute. Prior to the engine experiments, the evaporation behavior of the blended fuel was examined with single droplet evaporation on a hot plate, and the spray characteristics such as spray angle and penetration are discuseed using spray images in photos taken with single injections into air at high pressure and room temperature (1.57 MPa and 298 K). The performance and emissions of two types of small single cylinder DI diesel engines (engine A equipped with a bowl in piston type combustion chamber and a throttle nozzle, and engine B a toronidal type with a multi hole nozzle of 4- φ 0.2) were also examined. As a result, the blended fuels with equal proportions of gas oil and rapeseed oil or higher gas oil ratios showed good engine performance and emission characteristics, like those of gas oil operation.
To utilize ethanol from agricultural residue as a fuel in diesel engines, a dual-fuel engine was developed. The engine, which was equipped with a system to electrically control diesel and alcohol flow rates, met basic requirements of a tractor engine, including engine speed control and setting of the torque curve. However, engine knock due to alcohol was a significant drawback. A diesel injection pump with a timing and flow rate control system was adapted, and the effect of injection timing on combustion and performance was investigated. It was observed that the timing control was effective in reducing engine knock caused by rapid alcohol combustion.
An experimental study is conducted to evaluate the effects of using various blends of ethanol with normal diesel fuel, in blend ratios of 5/95, 10/90 and 15/85, on the performance and exhaust emissions of a high-speed, direct injection (DI), Ricardo/Cussons 'Hydra' diesel engine. The tests are conducted using each of the above fuel blends or neat diesel fuel. Volumetric fuel consumption, exhaust gas temperature, exhaust smokiness and exhaust regulated gas emissions such as nitrogen oxides, carbon monoxide and total unburned hydrocarbons are measured. The differences in the performance and exhaust emission parameters from the baseline operation of the engine, that is, when working with neat diesel fuel, are determined and compared. Theoretical aspects of diesel engine combustion are used to aid the interpretation of the engine behaviour.
An experimental study has been conducted to evaluate the use of various blends of cottonseed oil or its methyl ester (bio-diesel) with diesel fuel, in blend ratios from 10/90 up to 100/0, in a fully instrumented, four-stroke, High Speed Direct Injection (HSDI), Ricardo/Cussons 'Hydra' diesel engine. The tests were conducted using each of the above fuel blends or neat fuels, with the engine working at a medium and a high load. Volumetric fuel consumption, exhaust smokiness and exhaust-regulated gas emissions such as nitrogen oxides, carbon monoxide and unburnt hydrocarbons were measured. The differences in the performance and exhaust emissions from the baseline operation of the engine, that is, when working with neat diesel fuel, were determined and compared, as well as the differences between cottonseed oil or its methyl ester and their blends. Theoretical aspects of diesel engine combustion were used to aid the correct interpretation of the engine behaviour.
Although a first-law analysis can show the improvement that hydrogen addition impacts on the performance of a biogas-fuelled spark-ignition (SI) engine, additional benefits can be revealed when the second law of thermodynamics is brought into perspective. It is theoretically expected that hydrogen enrichment in biogas can increase the second-law efficiency of engine operation by reducing the combustion-generated irreversibilities, because of the fundamental differences in the mechanism of entropy generation between hydrogen and traditional hydrocarbon combustion. In this study, an experimentally validated closed-cycle simulation code, incorporating a quasi-dimensional multi-zone combustion model that is based on the combination of turbulent entrainment theory and flame stretch concepts for the prediction of burning rates, is further extended to include second-law analysis for the purpose of quantifying the respective improvements. The analysis is applied for a single-cylinder homogeneous charge SI engine, fuelled with biogas—hydrogen blends, with up to 15 vol% hydrogen in the fuel mixture, when operated at 1500r/min, wide-open throttle, fuel-to-air equivalence ratio of 0.9, and ignition timing of 20° crank angle before top dead centre. Among the major findings derived from the second-law balance during the closed part of the engine cycle is the increase in the second-law efficiency from 40.85 per cent to 42.41 per cent with hydrogen addition, accompanied by a simultaneous decrease in the combustion irreversibilities from 18.25 per cent to 17.18 per cent of the total availability of the charge at inlet valve closing. It is also illustrated how both the increase in the combustion temperatures and the decrease in the combustion duration with increasing hydrogen content result in a reduction in the combustion irreversibilities. The degree of thermodynamic perfection of the combustion process from the second-law point of view is quantified by using two (differently defined) combustion exergetic efficiencies, whose maximum values during the combustion process increase with hydrogen enrichment from 49.70 per cent to 53.45 per cent and from 86.01 per cent to 87.33 per cent, respectively.
In this study, one kind of vegetable methyl ester was added to ethanol–diesel fuel to prevent the separation of ethanol from diesel; thus the ethanol percentage can be up to 30% in volume. More attention was paid to its combustion characteristics, the effects of ethanol on particulate matter (PM) components, SOF (soluble organic fraction), DS (dry soot), and sulfate mass, using different fuel blends in the engine. To understand the effect of ethanol blended diesel fuels on combustion processes and soot formation, images of combustion processes were recorded using a high-speed CCD camera. The results show that with increasing ethanol in the blended fuel, both smoke and PM can be reduced, but the PM decrease is not as efficient as the smoke decrease. The smoke and PM behave differently even for one kind of fuel blend, and it is unreasonable to evaluate the PM emission by the smoke. In addition, under the same condition, increasing ethanol in the fuel blend, the DS emission in PM is reduced significantly, the sulfate emission hardly changes, and the SOF emission in PM is not reduced as expected. The results also indicate that addition of ethanol to diesel fuels the ignition is prolonged, maximum heat release ratio and peak pressure increase, and combustion duration is shortened. In addition, the flame luminosity in the combustion is decreased using blended fuels, which indicates that soot formation in fuel-rich regions is suppressed by the ethanol.
The effects of different ethanol–diesel blended fuels on the performance and emissions of diesel engines have been evaluated experimentally and compared in this paper. The purpose of this project is to find the optimum percentage of ethanol that gives simultaneously better performance and lower emissions. The experiments were conducted on a water-cooled single-cylinder Direct Injection (DI) diesel engine using 0% (neat diesel fuel), 5% (E5–D), 10% (E10–D), 15% (E15–D), and 20% (E20–D) ethanol–diesel blended fuels. With the same rated power for different blended fuels and pure diesel fuel, the engine performance parameters (including power, torque, fuel consumption, and exhaust temperature) and exhaust emissions [Bosch smoke number, CO, NOx, total hydrocarbon (THC)] were measured. The results indicate that: the brake specific fuel consumption and brake thermal efficiency increased with an increase of ethanol contents in the blended fuel at overall operating conditions; smoke emissions decreased with ethanol–diesel blended fuel, especially with E10–D and E15–D. CO and NOx emissions reduced for ethanol–diesel blends, but THC increased significantly when compared to neat diesel fuel.
An experimental investigation is conducted to evaluate the effects of using blends of n-butanol (normal butanol) with conventional diesel fuel, with 8%, 16% and 24% (by volume) n-butanol, on the performance and exhaust emissions of a standard, fully instrumented, four-stroke, high-speed, direct injection (DI), Ricardo/Cussons ‘Hydra’ diesel engine located at the authors’ laboratory. The tests are conducted using each of the above fuel blends or neat diesel fuel, with the engine working at a speed of 2000rpm and at three different loads. In each test, fuel consumption, exhaust smokiness and exhaust regulated gas emissions such as nitrogen oxides, carbon monoxide and total unburned hydrocarbons are measured. The differences in the measured performance and exhaust emission parameters of the three butanol–diesel fuel blends from the baseline operation of the diesel engine, i.e., when working with neat diesel fuel, are determined and compared. It is revealed that this fuel, which can be produced from biomass (bio-butanol), forms a challenging and promising bio-fuel for diesel engines. The differing physical and chemical properties of butanol against those for the diesel fuel are used to aid the correct interpretation of the observed engine behavior.
An experimental study is conducted to evaluate the effects of using neat cottonseed oil or its neat ME (methyl ester) bio-diesel, on the combustion behavior of a standard, high speed, direct injection (HSDI), ‘Hydra’ diesel engine located at the authors’ laboratory. Combustion chamber and fuel injection pressure diagrams are obtained at medium and high load using a developed, high-speed, data acquisition and processing system. A heat release analysis of the experimentally obtained cylinder pressure diagrams is developed and used. Plots of histories in the combustion chamber of the heat release rate and other related parameters reveal some interesting features, which shed light into the combustion mechanism when using these bio-fuels. These results, combined with the differing physical and chemical properties of the bio-fuels between themselves and against those for the diesel fuel, which constitutes the baseline fuel, aid the correct interpretation of the observed engine behavior performance- and emissions-wise. Moreover, the possible existence of cyclic (combustion) variability is examined as reflected in the pressure indicator diagrams, by analyzing for the maximum pressure and its rate, and the dynamic injection timing and ignition delay, by using statistical analysis for averages, standard deviations and probability density functions. The key results are that with the use of these bio-fuels against the neat diesel fuel case, the ignition delay is hardly affected, the fuel injection pressure diagrams are very slightly advanced accompanied with higher injection pressures, maximum cylinder pressures remain the same with the vegetable oil and slightly increased with the bio-diesel, maximum cylinder pressure rates are increased with the bio-diesel and decreased with the vegetable oil, while the cyclic irregularity is not affected with these bio-fuels remaining at the acceptable neat diesel fuel case levels.
The potential exists to displace a portion of the petroleum diesel demand with butanol and positively impact engine-out particulate matter. As a preliminary investigation, 20% and 40% by volume blends of butanol with ultra low sulfur diesel fuel were operated in a 1999 Mercedes Benz C220 turbo diesel vehicle (Euro III compliant). Cold and hot start urban as well as highway drive cycle tests were performed for the two blends of butanol and compared to diesel fuel. In addition, 35 MPH and 55 MPH steady-state tests were conducted under varying road loads for the two fuel blends. Exhaust gas emissions, fuel consumption, and intake and exhaust temperatures were acquired for each test condition. Filter smoke numbers were also acquired during the steady-state tests.
Lower proof ethanol is shown to be a viable alternate fuel for diesel engines. This type of ethanol can be manufactured economically in small distillation plants from renewable grain supplies. The effect of fumigation of ethanol proofs with a multipoint injection system on a turbocharged direct injection diesel engine at 2,400 rpm and three loads was studied. The addition of the water in the lower proofs reduced the maximum rate of pressure rise and peak pressure from pure ethanol levels. Both of these values were significantly higher than those for diesel operation. HC and CO emissions increased several times over diesel levels at all loads and also with increased ethanol fumigation. NO emissions were reduced below diesel levels for lower proof ethanol at all loads. The tests at this rpm and load with a a multipoint ethanol injection system indicate that lower (100 or 125) proof provides optimum performance.
A gasoline-type, low pressure injection system was used to spray ethanol into the intake ports of a 31 kW diesel tractor engine. The maximum practical levels of ethanol fumigation were determined at 12 combinations of load and speed, and for three proofs of ethanol. Up to 60 percent replacement of diesel fuel by ethanol was achieved. Factors limiting the level of ethanol fumigation were found to be misfiring at normal intake temperatures due to long ignition delay, and knocking at high intake temperatures. Efficiency increased slightly at full load, but decreased at part load. Available power was increased. (Refs. 10).
Variation of engine thermal efficiency in response to the addition of soybean oil ethyl ester to diesel fuel was analysed in terms of the in-cylinder phenomena and fuel properties. Blends with concentrations of up to 30% of soybean oil ethyl ester in volume were used turbocharged direct injection engine. Engine internal processes were studied by means of exergy balances based on engine indicating data, which provided information about the impact of biodiesel blending on the amount of fuel exergy exchanged through heat, work and mass transfer. The data obtained from this exergy analysis served to identify the causes of the alterations in brake thermal efficiency measured in dynamometric bench tests. Operating in full load conditions and fuelled with the B20 blend, the engine showed an average increase of 4.16% in brake thermal efficiency and a gross increase of 4.24% in indicated thermal efficiency in relation to its performance with mineral diesel fuel.
Significant improvements in smoke, particulate matter, NOx, THC, engine output and thermal efficiency were simultaneously achieved with highly oxygenated liquid fuels. Engine noise was also remarkably reduced for oxygenates with higher ignitability. The improvements in exhaust emissions and thermal efficiency depended almost entirely on the oxygen content in the fuels regardless of the oxygenate-diesel fuel blending ratio or type of oxygenate. Smoke emission decreased sharply and linearly with an increase in oxygen content and disappeared entirely at an oxygen content above 38 wt %, even at stoichiometric conditions. Smoke-free, low NOx diesel combustion with oxygenated fuels was achieved at stoichiometric conditions with the adoption of very high exhaust gas recirculation (EGR). NOx, THC and CO emissions were almost completely removed with a combination of high EGR and a three-way catalyst over a wide range of brake mean effective pressure (b.m.e.p.). The maximum b.m.e.p. with the highly oxygenated fuels was significantly higher than that with the conventional diesel fuel because b.m.e.p. was released from the smoke limits.
The purpose of this paper is to experimentally investigate the engine pollutant emissions and combustion characteristics of a diesel engine fueled with ethanol/diesel blended fuel. The experiments were performed using various proportions of ethanol/diesel blended fuels in a single-cylinder direct injection (DI) diesel engine. The engine performance parameters and emissions were measured and compared to those using the baseline diesel fuel. To gain insight into the combustion characteristics of ethanol/diesel blends, the engine combustion processes for blended fuels and diesel fuel were observed using an engine video system (AVL 513). The results show that the brake specific fuel consumption increased at overall engine operating conditions, but it is worth noting that the brake thermal efficiency increased by up to 1–2.3% with 10 and 15% ethanol/diesel blended fuels. It is found that engines fueled with ethanol/diesel blended fuels have higher emissions of total hydrocarbon (THC), and lower emissions of CO, NOx, and smoke. The results also indicate that the cetane number improver has a positive effect on CO and NOx emissions, but a negative effect on THC emission. Based on the engine combustion visualization and in-cylinder temperature field analysis by using the primary color method, it is found that the ignition delay increased, the total combustion duration and the luminosity of the flame decreased, and the peak combustion temperature decreased for ethanol/diesel blended fuels.
The rapid expansion of combustion products in a diesel cylinder generates high-frequency acoustic waves which cause errors in the computed heat-release signature. In this study, the effects of spline smoothing and digital filtering on the computed heat-release history were investigated. Experiments were performed on a heavy-duty single-cylinder diesel engine. In some cases the computed heat-release history was rendered unusable by the acoustic waves, which were centered at a frequency of 3.7 kHz for this engine, even after spline smoothing was applied to the pressure data. In contrast, a low-pass digital filter developed for this study was found to be very effective for removing acoustic noise from heat-release signatures without adversely affecting the computed indicated mean effective pressure.
The concept of using alcohol fuels as alternatives to diesel fuel in diesel engines is a recent one. The scarcity of transportation petroleum fuels which developed in the early 1970's spurred many efforts to find alternatives. Alcohols were quickly recognized as prime candidates to displace or replace high octane petroleum fuels. However, alternatives to the large demand for diesel fuel in many countries were not as evident. Innovative thinking led to various techniques by which alcohol fuels can partially or completely displace diesel fuel in diesel transportation vehicles. The methods of using alcohol fuels in diesel engines (in order of increasing diesel fuel displacement) include solutions, emulsions, fumigation, dual injection, spark ignition, and ignition improvers.
Three sequential studies of engine flows and combustion are reported. In the first, comparisons were made of computed and measured flame fronts and pressures in eight engine configurations. A 2-dimensional planar model was used. Conversion of reactants to products was assumed to be mixing controlled, and turbulence was simulated by a k-epsilon submode. Computations were started just prior to TDC from assumed initial values of k and epsilon deduced from experimental information. It was concluded that the mixing controlled model may be adequate to represent the main behavior of engine flames but not wall quenching, selfignition, and flammability limits. In the second study, the question of what appropriate initial conditions for near-TDC computations was reevaluated. Comparisons were made of computed and measured turbulence and tangential velocities in nine motored engine configurations. A 2-dimensional axisymmetric model was used, and a k-epsilon submodel was again employed. Computations were started from various initial conditions and at various crank angles. It was concluded that TDC turbulent intensity is proportional to engine speed, linear-to-insensitive to load, and insensitive-to-mildly-decreasing with compression ratio, depending on the chamber design and the strength of the swirl. It was also concluded that in the absence of strong non-uniformities and bulk flows at BDC and for pancake-like combustion chambers, TDC turbulence is spatially uniform and insensitive to BDC conditions. With swirl or squish (or both), TDC turbulence is no longer spatially uniform and tends to be determined by the details of swirl and/or chamber design. The objective of the third study was to develop a 3-dimensional model to assess the validity of using 2-dimensional models in actual engine applications. The objective was not achieved due to computer limitations, but a new numerical method was selected.
The present study focuses on the investigation of the formation of CO and unburned oxygenated and nonoxygenated hydrocarbon emissions from HCCI engines fueled with neat ethanol and neat isooctane. This is achieved with the use of a multizone model, which describes the essential features of HCCI combustion, that is, heat and mass transfer within the combustion chamber, both of which are modeled using phenomenological submodels. These mechanisms affect the formation of the main HCCI engine pollutants, namely, unburned hydrocarbons and carbon monoxide. Combustion is simulated using chemical kinetics coupled to oxidation mechanisms for isooctane and ethanol. These mechanisms also describe the decomposition of the original fuel into intermediate hydrocarbons and carbon monoxide. A validation of the model for both fuels is given for various load cases. In the numerical investigation, the formation of CO is described for the corresponding experimental cases and the essential features of the transition from CO production due to bulk quenching and to CO production due to postcombustion partial HC oxidation are shown. Additionally, the formation of HC emissions is described including both oxygenated and nonoxygenated compounds. This distinction was found to be necessary since both fuels include oxygenated species in the exhaust gases, the relative amount of which depends on load conditions and the fuel used. The fraction of oxygenated compounds to total unburned HC is high for ethanol at all loads, primarily due to the presence of ethanol, acetaldehyde and formaldehyde, in descending order of importance. The relative proportion of oxygenates in total unburned HC in the case of isooctane was found to depend on load. These findings raised questions regarding the assessment of unburned hydrocarbon emissions using conventional measuring devices, such as the FID. For this reason the relative error in the FID measurement was estimated, using the simulated HC composition results and the FID relative response of each of the species constituting the HC.
This paper presents an analysis of the cycle-by-cycle combustion variation as reflected in the pressure indicator diagram of a single-cylinder, naturally aspirated, four-stroke, direct-injection, Lister LV1 diesel engine. A measuring set-up consisting of piezoelectric transducers with charge amplifiers, in the cylinder and the fuel injection pipeline, and a fast data-acquisition board installed on an IBM-compatible microcomputer was used to gather the data of 650 successive combustion cycles of the cylinder, under various combinations of injection timing and load conditions. The measured data were corrected for drift, and the top dead centre of each cycle is determined thermodynamically. The data obtained by this technique were analysed for the peak pressure, the peak rate of pressure rise, the crank angles at which these maximum values occur, and for the injection timing and ignition delay. The groups of parameters have been further statistically analysed for averages, standard deviations, probability density functions, autocorrelations and power spectra. Crosscorrelation runs were also performed to observe any cause relationship between cyclic pressure variations and the fuel-injection-system operation. The results of the stochastic analysis technique have proved to be very useful for the investigation and interpretation of the existence of fluctuation phenomena in the diesel internal combustion engine and their cause relationships, thereby aiding the correct interpretation of the relevant experimental results and their associated errors.
An experimental investigation on the application of the blends of ethanol with diesel to a diesel engine was carried out. First, the solubility of ethanol and diesel was conducted with and without the additive of normal butanol (n-butanol). Furthermore, experimental tests were carried out to study the performance and emissions of the engine fuelled with the blends compared with those fuelled by diesel. The test results show that it is feasible and applicable for the blends with n-butanol to replace pure diesel as the fuel for diesel engine; the thermal efficiencies of the engine fuelled by the blends were comparable with that fuelled by diesel, with some increase of fuel consumptions, which is due to the lower heating value of ethanol. The characteristics of the emissions were also studied. Fuelled by the blends, it is found that the smoke emissions from the engine fuelled by the blends were all lower than that fuelled by diesel; the carbon monoxide (CO) were reduced when the engine ran at and above its half loads, but were increased at low loads and low speed; the hydrocarbon (HC) emissions were all higher except for the top loads at high speed; the nitrogen oxides (NOx) emissions were different for different speeds, loads and blends.
The oxidation of neat 1-butanol and a mixture of n-heptane and 1-butanol was studied in a modified CFR engine at an equivalence ratio of 0.25 and an intake temperature of 120 °C. The engine compression ratio was gradually increased from the lowest point to the point where significant high temperature heat release was observed. Heat release analyses showed that no noticeable low temperature heat release behavior was observed from the oxidation of neat 1-butanol while the n-heptane/1-butanol mixture exhibited pronounced cool flame behavior. Species concentration profiles were obtained via GC–MS and GC-FID/TCD. Quantitative analyses of the reaction products from the oxidation of neat 1-butanol indicate that 1-butanol is consumed mainly through H-atom abstraction. Among the H-atom abstraction reactions, it is observed that the H-atom abstraction from the α-carbon of 1-butanol is particularly favored. The investigation on the oxidation of the mixture of n-heptane/1-butanol showed that the oxidation of 1-butanol is facilitated at low temperatures through the radical pool generated from the oxidation of n-heptane.