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Effects of Ethanol on Vehicle Energy Efficiency and Implications on Ethanol Life-Cycle Greenhouse Gas Analysis
Abstract
Bioethanol is the world's largest-produced alternative to petroleum-derived transportation fuels due to its compatibility within existing spark-ignition engines and its relatively mature production technology. Despite its success, questions remain over the greenhouse gas (GHG) implications of fuel ethanol use with many studies showing significant impacts of differences in land use, feedstock and refinery operation. While most efforts to quantify life-cycle GHG impacts have focused on the production stage, a few recent studies have acknowledged the effect of ethanol on engine performance and incorporated these effects into the fuel life cycle. These studies have broadly asserted that vehicle efficiency increases with ethanol use to justify reducing the GHG impact of ethanol. These results seem to conflict with the general notion that ethanol decreases the fuel efficiency (or increases the fuel consumption) of vehicles due to the lower volumetric energy content of ethanol when compared to gasoline. Here we argue that due to the increased emphasis on alternative fuels with drastically differing energy densities, vehicle efficiency should be evaluated based on energy rather than volume. When done so, we show that efficiency of existing vehicles can be affected by ethanol content, but these impacts can serve to have both positive and negative effects and are highly uncertain (ranging from -15% to +24%). As a result, uncertainties in the net GHG effect of ethanol, particularly when used in a low-level blend with gasoline, are considerably larger than previously estimated (standard deviations increase by >10% and >200% when used in high and low blends, respectively). Technical options exist to improve vehicle efficiency through smarter use of ethanol though changes to the vehicle fleets and fuel infrastructure would be required. Future biofuel policies should promote synergies between the vehicle and fuel industries in order to maximise the society-wise benefits or minimise the risks of adverse impacts of ethanol.
... Initiatives targeting the fuel economy of light-duty vehicles have been put in place in Saudi Arabia and aim to increase Saudi Arabia's fuel economy by 4% by 2020 (SASO, 2015). However, besides improving vehicles' fuel efficiency, making use of renewable and alternative fuel sources on a larger scale may also prove to be an effective measure to reduce GHG emissions from road transport (Lutsey and Sperling, 2008;Maniatopoulos et al., 2015;Yedla et al., 2005;Hawkins et al., 2013;Yan et al., 2013;Liu, 2006;Yan and Crookes, 2009;Yang et al., 2009). Electricity and hydrogen may all yield significant reductions in GHG emissions as compared to fossil fuels (Maniatopoulos et al., 2015). ...
... Ethanol, on the other hand, has largely been used as an alternative fuel to petroleumderived transportation fuel. However, uncertainty levels remain high in regards to the net GHG effect of ethanol, particularly when used in a low-level blend with gasoline (Yan et al., 2013;Yan and Crookes, 2009). ...
Climate change has become a global issue affecting the environment and human health. Transportation is a major contributor of greenhouse gases (GHG) emissions, with road transport being responsible for more than half of these emissions. The main objective of this thesis was to estimate the carbon footprint associated with road projects in the city of Abu Dhabi following a comprehensive approach that considers all activities within the life cycle of roads. Three cases were considered, including, Al Rahba City internal road network, the upgrading of Al Salam Street, and the widening of the Eastern Corniche Road. A carbon footprint estimation model (referred to as RoadCO₂) was developed to estimate GHG emissions of the three road cases. The model considers emissions from all phases of road projects and reports emissions in terms of carbon dioxide equivalent (CO₂eq). The methodology suggested by the Intergovernmental Panel on Climate Change (IPCC) was adopted in constructing the model. Results revealed that the total emissions from the construction of the investigated road cases are about 43, 292, and 16 thousand tons CO₂eq, respectively. Equipment used in construction contributed about 70%, 15%, and 21% of the total emissions of the construction phase, respectively. The rest of the emissions during the construction phase originated from the use of construction materials and their associated transport. Upgrading of Al Salam Street project produced the highest emissions from construction materials due to the construction of a tunnel. Annual total emissions during the operation phase of Al Salam Street were estimated to be over 108 thousand tons CO₂eq/yr, whereas emissions during the operation phase for Al Rahba City internal roads were about 15 thousand tons CO₂eq/yr, and those for the Corniche Road were 91 thousand tons CO₂eq/yr. For the three cases, emissions were generated mainly during the operation phase (94% or more), with the main contributor being vehicle movement, followed to a lesser extent by street lighting.
... ( Karavalakis et al. 2015) [11] CO decreased with increasing O2 content in the mixture for some of the vehicle fuel mixtures. ( Anderson et al. 2012) [12] ( Yan et al. 2013) [13] However, there are some disadvantages to the aid of ethanol as a gasoline extender. These combine ethanol's weaker energy content related to gasoline . ...
... ( Karavalakis et al. 2015) [11] CO decreased with increasing O2 content in the mixture for some of the vehicle fuel mixtures. ( Anderson et al. 2012) [12] ( Yan et al. 2013) [13] However, there are some disadvantages to the aid of ethanol as a gasoline extender. These combine ethanol's weaker energy content related to gasoline . ...
This study reports exhaust emission evaluation for internal combustion engines laboratory of four-stroke, single-cylinder, water cooled system, in constant speed (1000-3000 rpm), SI engine. Exhaust gas emissions, carbon monoxide CO, unburned hydrocarbon HC and carbon dioxide CO2 emissions levels were estimated at many speed operation of the engine. The engine was operated with different types of fuel. It was observed that when the engine is fuelled by alcohol fuel, the volumetric ratio of the exhaust pollutants is minimum compared to the rest of the varieties of fuel and even when the catalyst converter is used.
International Journal of Mechanical Engineering and Technology (IJMET)
... ( Karavalakis et al. 2015) [11] CO decreased with increasing O2 content in the mixture for some of the vehicle fuel mixtures. ( Anderson et al. 2012) [12] ( Yan et al. 2013) [13] However, there are some disadvantages to the aid of ethanol as a gasoline extender. These combine ethanol's weaker energy content related to gasoline . ...
... ( Karavalakis et al. 2015) [11] CO decreased with increasing O2 content in the mixture for some of the vehicle fuel mixtures. ( Anderson et al. 2012) [12] ( Yan et al. 2013) [13] However, there are some disadvantages to the aid of ethanol as a gasoline extender. These combine ethanol's weaker energy content related to gasoline . ...
This study reports exhaust emission evaluation for internal combustion engines laboratory of four-stroke, single-cylinder, water cooled system, in constant speed (1000-3000 rpm), SI engine. Exhaust gas emissions, carbon monoxide CO, unburned hydrocarbon HC and carbon dioxide CO2 emissions levels were estimated at many speed operation of the engine. The engine was operated with different types of fuel. It was observed that when the engine is fuelled by alcohol fuel, the volumetric ratio of the exhaust pollutants is minimum compared to the rest of the varieties of fuel and even when the catalyst converter is used.
... Ethanol has been used as an oxygenate additive of gasoline in several nations (Hu et al., 2004). The oxygen atom in the molecular structure of ethanol makes it burn completely and produce higher efficiency (Yan et al., 2013). Eyidogan et al. (2010) prove through experiments that compared to unleaded gasoline, E5 (5% ethanol and 95% gasoline, V/V) and E10 can increase thermal efficiencies by 1.9% and 2.5%, respectively, at 100 km/h. ...
... The presence even small amounts of ethanol will improve the water solubility of ethanol gasoline, and it prefers to absorb steam from the air (Baena et al., 2012;Yan et al., 2013). A certain amount of water can easily lead to phase separation and corrosion problems (Jafari et al., 2011;Lou and Singh, 2010). ...
Currently, car ownership in China accounts for 20% of the world's cars, and there is tremendous growth potential in China's motor vehicle market, along with the quick improvement of the urbanization level. These advances will gradually increase the energy and environmental pressures faced by China. A direct and effective method to address these issues is to develop alternative vehicle fuels. This paper elaborates on the necessity and feasibility of developing fuel ethanol in China by comparing fuel ethanol with five kinds of alternative fuels that have either been put into use or are in the demonstration stage. Additionally, we construct a triple-perspective (raw material resource-vehicle-infrastructure) analysis framework. Based on this framework, the review concludes that China should develop 1.5-generation bioethanol in accordance with its own conditions in view of raw material resources. Compared with gasoline, bioethanol has the advantages of having an antiknock ability, engine efficiency and torque output from the perspective of the vehicle, but it also has some performance disadvantages. For infrastructure, the policies regarding using marginal land for planting energy crops lack specific and definite goals. Therefore, the government should increase its investment and develop new varieties of 1.5-generation bioethanol with higher quality and yield; step up efforts to help consumers understand that ethanol is a safer and more friendly antiknock additive than methyl tertiary butyl ethers (MTBE), which should be limited in its additive amount; and assess the environmental and economic feasibility of marginal land used for energy crops.
... However, the monotonic trends can differ among pollutants (Liu and Frey, 2015). Furthermore, FFV engines may be more efficient when operating on E85 than on gasoline (Yan et al., 2013). Differences in energy use may vary with VSP. ...
... However, the real-world and dynamometer-based empirical differences are not as low as the theoretical expectation of -29% (Zhai et al., 2009). This is because engines running on E85 have higher energy efficiency than on gasoline (Roberts, 2008;Yan et al., 2013). Combustion of ethanol results in higher peak pressure compared to gasoline due to differences in ignition delay and combustion duration. ...
Implications:
Reported comparisons of flex fuel vehicle (FFV) tailpipe emission rates for E85 versus gasoline have been inconsistent. To date, this is the most comprehensive evaluation of available and new data. The large range of inter-vehicle variability illustrates why prior studies based on small sample sizes led to apparently contradictory findings. E85 leads to significant reductions in tailpipe nitrogen oxide (NOx) and carbon monoxide (CO) emission rates compared with gasoline, indicating a potential benefit for ozone air quality management in NOx-limited areas. The comparison of FFV tailpipe emissions between E85 and gasoline is sensitive to power demand and driving cycles.
... Since bioethanol is compatible with conventional spark-ignition engines and relatively mature in production technology, it is the largest produced alternative fuel used in fossil fuel driven vehicles [49]. According to the mid and long term development strategies of the Chinese government, by 2020 China will increase its annual ethanol production capacity to 10 Mt to reduce GHG emissions from transportation sector and two-third of that ethanol will be produced from non-food sources [50]. ...
... The analysis revealed that field-to-wheels performance is similar for both pathways although some of the scenarios indicate biofuel as more efficient fuel. Therefore to increase the benefit of the society i.e. to reduce the adverse impacts of ethanol, appropriate biofuel policies should be taken to promote synergies between fuel and vehicle industries [49]. Many studies indicated that, the implication of ethanol use on greenhouse gas varies with the changes in refinery operation. ...
The world is experiencing a tremendous growth in transportation sector which is also prevalent in Saudi Arabia. This phenomenon results in an increasing demand for fossil fuel for both national and international transportation. This study presents the (i) analysis of the historical fossil fuel energy consumption trend, (ii) forecasted energy consumption using double exponential smoothing method, (iii) study of estimated and projected emissions of greenhouse gas (GHG), (iv) factors influencing GHG emissions, (v) potential mitigation measures, and (vi) mitigation initiatives to reduce GHG emissions from the road transportation sector of the Kingdom. This study revealed that the per capita fuel consumption in Saudi Arabia is increasing at higher rates in recent years compared to some other neighboring countries along with the consistent increase in number of cars and population growth. As a result, the domestic fuel consumption is growing significantly and the growth dynamics of GHG emissions is becoming quite challenging for planning, development, and implementation of appropriate mitigation measures. An integrated national effort with strong commitments from all the stakeholders is a strategic imperative for the Kingdom to ensure its rapid development and successful implementation of commendable national policy for reducing the emission of GHG, particularly from the road transportation sector. Success of the Kingdom’s efforts to manage GHG emissions from the road transportation sector while maintaining its ambitious development stride and commitments to a stable global energy supply demands increased and comprehensive focus on vehicle efficiency, environment friendly fuels, and management of growing travel demand considering the specific socio-economic characteristics.
... Ethanol produced from sugars and starch from corn is the first generation of ethanol production. In Brazil, ethanol from sugarcane has been utilised in the transportation sector since 1975, and it has been used as a gasoline blend (ethanol mixed with gasoline) or as pure ethanol in vehicles [1,2]. Due to rising prices and decreasing oil supplies, many countries such as the USA, European Union (EU) and Asian countries like Thailand have adopted this platform to substitute for pure gasoline; partial substitutiondblends of 5e20% ethanol by volume in gasolinedis common in vehicles at the present time [2,3]. ...
... In Brazil, ethanol from sugarcane has been utilised in the transportation sector since 1975, and it has been used as a gasoline blend (ethanol mixed with gasoline) or as pure ethanol in vehicles [1,2]. Due to rising prices and decreasing oil supplies, many countries such as the USA, European Union (EU) and Asian countries like Thailand have adopted this platform to substitute for pure gasoline; partial substitutiondblends of 5e20% ethanol by volume in gasolinedis common in vehicles at the present time [2,3]. The procedure for starch-based ethanol production typically includes saccharification and fermentation. ...
Plant biomass, or lignocellulosic biomass, is evaluated worldwide as a potential feedstock for the sustainable production of bioenergy in the near future due to its abundance, availability and renewability. Promising sources of plant biomass include agricultural residues and energy crops; however, the natural recalcitrance of this material is a major bottleneck for lignocellulose-derived ethanol production. The current process requires pre-treatment with severe conditions to disrupt the plant cell wall structures and remove hemicellulose and lignin components so that cellulose is more accessible to cellulases. However, the generation of enzyme inhibitors/deactivators and toxic substances during pre-treatment may subsequently affect enzymatic saccharification and fermentation processing. The pre-treatment and saccharification processability can be simplified if the plant biomass resistance to biochemical or enzymatic treatment is reduced. While there are many developed pre-treatment technol- ogies and formulated enzyme cocktails that match pre-treated substrates, there has been attempt to design ideal energy crops via plant genetic manipulation. Cellulose engineering is aimed at reducing the crystallinity of cellulose structures. Expression of cellulose-disrupting proteins, including carbohydrate-binding modules, expansins, and swollenins, produces irregular forms of cellulose fibrils, which change from tightly packed fibrils to splayed ribbons with a high sugar release after enzymatic treatment. In addition, modifying genes and proteins involved in cellulose synthesis resulted in an unusual secondary cell wall deposition and composition and a lower crystallinity index. Reducing lignin content though engineering lignin biosynthesis pathways improves the saccharification process; however, abnormal growth and plant fitness remain problematic when improper genes are selected for manipulation. Lignin composition can be modified by introducing phenolic derivatives or peptide cross-links upon lignification, and these approaches might minimise the interference with plant growth and development. Hemicellulose biosynthesis is a complicated process. Currently, the reduction of hemicellulose content relies mostly on enzymes involved in xyloglucan/glucoarabinoxylan synthesis and the arrangements of those polymers in developing wood. Additionally, several glycosyltransferase and glycoside hydrolases are believed to be involved in hemicellulose modification in relation to loosened cell walls. Importantly, the expression of foreign glycoside hydrolases in plants may facilitate the reduction of enzyme loadings, thus making lignocel- lulosic ethanol production economically viable.

... It is currently blended with gasoline in several countries, and it is also a major fuel in Brazil (Ramadhas 2011). In China, for instance, ethanol vehicles are vehicles that are fueled with gasoline blended with a lower percentage of ethanol which is produced from crops or biomass (Jiao et al. 2019;Tzeng et al. 2005;Yan et al. 2013). China, with its good potential for ethanol fuel manufacturing, has encouraged the utilization of ethanol vehicles in granary-rich provinces to help speed up the country's energy transition and also decrease the life cycle energy utilization and environmental pollution (Li et al. 2019a, b). ...
Currently, internal combustion engines and fossil fuels are the major powertrains and fuels for the transportation sector,
despite their enormous emissions. This study reviews the status of electric vehicles (EVs) in Africa, the potential barriers
that affect their large-scale adoption, and the continent’s potential to produce cleaner alternative fuels for transportation and
find the strengths, weaknesses, opportunities, and threats (SWOT) to produce alternative fuels in Africa. First, the review
looked at challenges confronting the adoption of EVs in Africa, some of which include high upfront costs, poor grid systems,
frequent blackouts, inadequate infrastructure (roads and charging systems), and the dominance of used conventional vehicles.
The various cleaner alternative fuels, i.e., hydrogen, biogas, ethanol, methanol, ammonia, biodiesel, and vegetable oils, and
their potential on the African continent were also reviewed. The last section of the study employed the SWOT analytical
tool to assess the strengths, weaknesses, opportunities, and threats in the alternative fuel industry in Africa. Factors such as
competition from existing technologies, inadequate funding, feeble linkages between research and production, unsustainable
policies for the sector, cultural constraints and lack of awareness, volatile financial systems, and low levels of foreign direct
investment are some of the identified threats that could affect the development of alternative fuels in Africa. Similarly, factors
such as the continuous decline in the cost of renewable energy technologies and heightened awareness of the adverse effects
of GHG on the environment were identified as opportunities for the development of alternative fuels for the transport sector.
... Its ultimate objective lies in fostering a harmonious co-development between humanity and the natural environment (Nishii, 2011). The comprehensive evaluation of green management involves encompassing all facets of environmental relevance within the realm of enterprise production and operations (Inderwildi et al., 2013). This evaluation serves as a powerful tool in gauging whether the activities align with the requisites of green management, thus encouraging enterprises to bolster the green production efficiency and elevate product quality. ...
... Moreover, ethanol has relatively clean, green, and renewable characteristics, which has attracted the attention of many countries [1]. Ethanol-gasoline is a mixture of ethanol (C 2 H 6 O) and gasoline in a certain proportion, which has the advantages of high octane and good antiknock performance [2]. Since 2003, Heilongjiang, Jilin, Shandong, Henan, Liaoning and other provinces in China have changed the gasoline to ethanol-gasoline (10%/90%) ethanol in succession. ...
The vehicle exhaust remote sensing system was used to quantify the carbon monoxide (CO), hydrocarbon (HC), and nitrogen oxide (NO) concentrations of vehicles before and after the ethanol-gasoline implementation. The purpose was to investigate gasoline vehicle emissions for two distinct periods: before and after the ethanol-gasoline implementation. A comprehensive vehicle emission remote sensing data set collected in 2018 and 2019. The remote sensing test data was screened for duplicate vehicles in both two years. The average emission concentration of HC-CO-NO showed a continuous downward trend after ethanol-gasoline implementation. The three pollutant emission factors of small passenger cars are all lower than those of light trucks. Overall, the HC-CO-NO emission factors obtained through remote sensing tests have a small range of variation. From the results of the two-year test data, the emission levels of the 10% worst emission vehicles have shown a certain reduction compared with before the ethanol-gasoline implementation. Compared with random test errors of dynamometer emission test and portable emission measurement system, statistical results based on remote sensing test big data are more accurate.
... The selection of lignocellulosic crops likely depends on quantity and agronomic considerations including seasons, environment, and regional geography. In Brazil, ethanol from sugar cane has been utilized in the transportation sector since 1975 (Yan et al., 2013). In the USA, switchgrass is the leading dedicated energy crop that has been selected for ethanol production (Keshwani and cheng 2009). ...
... Electric vehicle support [11,[28][29][30][31][32]] A price on carbon or increased fuel price [11,28,29] Active and/or public transport support [11,29,[33][34][35] Biofuel, hydrogen fuel and/or other alternative transport fuel [28,[36][37][38][39] Vehicle fuel efficiency [11,28,29] Travel demand management [21,33,40] ...
... Equation (2) presents the adjustment procedure. [65]. The contribution of thermodynamic efficiency improvements to ethanol benefits is therefore estimated by simulating an additional case with no efficiency improvements due to ethanol level and comparing it with the default simulations. ...
Replacing conventional gasoline with mid-level ethanol blends (15–30% ethanol by volume) can reduce fossil fuel use and greenhouse gas (GHG) emissions but require vehicle compatibility. This study quantifies the changes in fuel volumes and well-to-wheel (WTW) GHG emissions associated with potential mid-level ethanol blend deployment in Canada's light-duty vehicle fleet from 2018 to 2030. We develop a Canadian fleet model that projects the number of vehicles by vehicle technology and production year from 2015 to 2030, their fuel blend compatibilities, and their annual fuel use, considering the potential effects of ethanol blend level on vehicle fuel consumption and associated GHG emissions. The results show that the deployment of low and mid-level ethanol blends, such as E10, E15 or E25, could reduce petroleum gasoline use by 12% in 2030, while tripling ethanol use, from 2.6 to 7.2 billion liters annually. Incorporating emission factors from the GHGenius model suggests that mid-level blends can reduce fleet WTW GHG emissions in 2030 by 7.2% assuming the use of corn and wheat ethanol, and by up to 13.4% assuming cellulosic ethanol. The octane enhancing effect of ethanol is responsible for up to 30% of the reductions. Achieving the above reductions would require coordination among vehicle manufacturers, refiners and policymakers. Overall, mid-level blends can materially reduce GHG emissions of the Canadian light-duty fleet, but represent less than 1/5 of the reductions required for the light-duty fleet to achieve emissions that are 30% below 2005 levels (Canada's pledge under the Paris Agreement).
... Ethanol is now found at most public gas stations in some countries due to the laws and recommendations the Alternative Motor Fuels Act (AMFA) (1988) [18], Clean Air Act (1990), Energy Policy Act (2005) and most importantly The Renewable Fuel Standard Program September 2006. Ethanol is the world's most popular biofuel for use with existing spark-ignition (SI) engines [19]. The increase in ethanol use has been promoted by several legislative measures, including the Energy Independence and Security Act (EISA 2007) and the Renewable Fuel Standard (RFS), which was initiated in 2005 and expanded in 2007 [20]. ...
Bio-fuels are important because they replace petroleum fuels. A number of environmental and economic benefits are claimed for bio-fuels. Bio-ethanol is by far the most widely used bio-fuel for transportation worldwide. Production of bio-ethanol from biomass is one way to reduce both consumption of crude oil and environmental pollution. Using bio-ethanol blended gasoline fuel for automobiles can significantly reduce petroleum use and exhaust greenhouse gas emission. Bio-ethanol can be produced from different kinds of raw materials. This paper reviews the current status of the technology for ethanol production. The effect of the fuel on engine performance, durability and emissions is also considered. Ethanol is an attractive alternative fuel because it is a renewable bio-based resource and it is oxygenated, thereby providing the potential to reduce particulate emissions in spark-ignition engines. This paper reviews the existing procedures for ethanol production, atmospheric aspect of ethanol fuel, ethanol as fuel and performance evaluation of ethanol. About 71 published studies (1980-2015) are reviewed in this paper. It is marked from the literature survey articles that ethanol blends performance are the most frequently studied as an alternative fuel.
... To understand and compare the environmental performance of bioethanol technologies and strategies, many studies have conducted life cycle assessment (LCA) on different systems with specific focuses, including cropping system [14], feedstock supply [15], soil sustainability [9,16] and vehicle energy efficiency [17]. On a technological level, although some LCA studies have addressed the conversion of corn stover to ethanol including biotechnological, chemical and thermochemical processes [18][19][20][21], the literature is not conclusive as to which technologies look most promising from a global warming perspective. ...
Bioethanol from residual corn stover could contribute to lowering CO 2 loads within the transport sector, if used as an amendment to gasoline. We modelled by life cycle assessment and Monte Carlo simulation seven different technological configurations for producing bioethanol from corn stover based on consistent mass flows and estimated ethanol production extracted from 141 datasets of reasonable quality. By parametrizing key processes and determining their statistical distribution based on actual data, we were able to estimate the Global Warming Potential (GWPs) for all the alternative technologies on a system level. Most of the individual cases showed a net saving in GWP when the savings obtained from recovering energy from anaerobic digestion of the liquid residues and incineration of the solid residues were included. The net savings could in some cases be as high as 900 ∼ 1200 kg CO 2 -eq/t dry corn stover solids. If the residues were not subject to energy recovery, the production of bioethanol and use in gasoline would be a net load to global warming in more than 50% of the technological configurations. The “best-practice”, defined as the top 15% cumulative probability with respect to GWP, suggests that technologies based on steam explosion and ammonia-based pretreatment appear statistically the most promising and could contribute, with residue energy recovery, to GWP savings of 850–1050 kg CO 2 -eq/t dry corn stover solids and produce in the range 178–216 kg of bioethanol. This paper provides insights into the key parameters for bioethanol production from corn stover and suggests areas for further research.
... For each of the four fuels, idling (i.e., mode 3) resulted in the lowest fuel use and emission rates. The modal average fuel use and emission rates typically increased monotonically with positive VSP (i.e., modes [4][5][6][7][8][9][10][11][12][13][14]. The CO 2 emission rate has a similar relative trend with fuel use rate because most of the carbon in the fuel was emitted as CO 2 . ...
Differences in fuel use and emission rates of carbon dioxide (CO 2), carbon monoxide (CO), hydrocarbons (HC), nitrogen oxide (NO x), and particulate matter (PM) were quantified for three gasoline-ethanol blends and neat gasoline measured for one flexible-fuel vehicle (FFV) and four non-FFVs using a portable emission measurement system (PEMS). The purpose was to determine if non-FFVs can adapt to a mid-level blend and to compare the fuel use and emission rates among the fuels. Each vehicle was measured on neat gasoline (E0), 10% ethanol by volume (E10) "regular" (E10R) and "premium" (E10P), and 27% ethanol by volume (E27). Four real-world cycles were repeated for each vehicle with each fuel. Second-by-second fuel use and emission rates were binned into Vehicle Specific Power (VSP) modes. The modes were weighted according to real-world standard driving cycles. All vehicles, including the non-FFVs, were able to adapt to E27. Octane-induced efficiency gain was observed for higher octane fuels (E10P and E27) versus lower octane fuels (E0 and E10R). E27 tends to lower PM emission rates compared to E10R and E10P and CO emission rates compared to the other three fuels. HC emission rates for E27 were comparable to those of E10R and E10P. No significant difference was found in NO x emission rates for E27 versus the other fuels. Intervehicle variability in fuel use and emission rates was observed. Lessons learned regarding study design, vehicle selection, and sample size, and their implications are discussed.
... At the current stage, ethanol vehicles in China refer to vehicles which are fueled with gasoline blended with low proportion ethanol which could be made from biomass or crops (Yan et al., 2013;Jiao et al., 2019). With a good foundation in developing ethanol fuel, China has promoted ethanol vehicles in granary-rich provinces to accelerate energy transition and reduce life-cycle energy consumption and emissions (NEA, 2017;Wang et al., 2018;Jiao et al., 2018). ...
To resolve socioeconomic and environmental issues caused by vehicular emissions, the Chinese government has developed a series of policies for promoting clean energy vehicles (CEVs), which can be powered by electricity, gas, ethanol or methanol. Effective implementation of these policies requires a comprehensive evaluation of CEVs. Decision-makers need to take into account multiple criteria such as energy performance, energy cost, vehicular emission, market acceptance and energy security. This paper proposes a decision support model, which applies multi-criteria analysis to prioritize CEVs existing and to be launched on the Chinese market. Government officials, academic researchers and industrial executives are interviewed to select and rank criteria for optimizing decision-making using the Analytic Hierarchy Process and the VIKOR optimization techniques. Thirty-five experts have been interviewed for prioritizing four categories of CEVs including electric, gas, methanol and ethanol vehicles from both the national and provincial perspectives. Results demonstrate that electric vehicles represent the highest ranking, followed by gas, methanol and ethanol vehicles. The proposed model has been validated using statistical data and existing government policies. The proposed multi-criteria analysis can be used for advising decision-makers in the area of clean energy vehicles.
... On the other hand, the liquid property of ethanol made its storage and dispensing similar to fossil gasoline (Emad, S et al, 2013;Wen-Yinn, L et al, 2010). Moreover, ethanol was considers as an additive substituting MTBE (methyl tertiary butyl ether was a gasoline additive for octane number improving) in the future because of its characteristics such as unleaded, uncontaminated groundwater, unharmed human health (Yan, X et al, 2013;Maria, A.C et al, 2016). Besides, bioethanol showed many advantages about physicochemical properties compared to fossil gasoline such as high octane number, increase in thermal efficiency and torque of engine (Sebayang, A.H et al, 2017;Hsi, H.Y et al, 2012), workability with high compression ratio for indirect-injection-gasoline engine without knocking, easy blend with gasoline (Omar, I.A et al, 2018;Yung, C.Y et al, 2013). ...
Pollutant emission from motorcycles in Vietnam where is among the countries with the highest number of motorcycles is very serious problem. From the beginning of 2018, biogasoline E5 will be officially distributed nationwide, and in the next stage, biogasoline E10 will be used in 2019 to replace the as-used fossil gasoline. This work presents the results of empirical research about engine performance, and emission characteristics as using biogasoline E10 for the most popular motorcycle Honda Wave RX110 in Vietnam. As showed results, there are the increases in engine power, thermal efficiency, NOx and CO2 emissions, otherwise, the reduction of fuel consumption, CO emission, HC emission in comparison with E5 and fossil gasoline-RON95 are reported. This study result is the proof of confirmation about the benefits of in-using biogasoline, diversification of fuel sources and reduction of environmental pollution.
... The increase in the number of production plants and consumption of ethanol definitely need a safety system to monitor its concentration level in both indoor and outdoor environments to avoid accidents and health issues. 2 The standard exposure limit of ethanol in air is 1000 ppm, and a fixed level of 3300 ppm is the maximum noted by the Occupational Safety and Health Administration (OSHA), 3 the National Institute of Occupational Safety and Hygiene (NIOSH), and the Centers for Disease Control and Prevention (CDC). 4 Airborne ethanol causes headache, fatigue, and sleepiness, while maximal and continuous exposure could do irreversible damage to the nerves (including causing dementia). ...
... A recent report by Oak Ridge National Laboratory (ORNL) concluded that use of mid-level ethanol blends (E25-E40) in future vehicles designed for such fuels, could have volumetric fuel economy parity with E10 [7]. It should be noted, however, that actual efficiency gains from using ethanol-containing fuels vary greatly depending upon engine type and operating conditions [8]. ...
To address issues of energy security and greenhouse gas (GHG) mitigation, substantial amounts of corn-derived ethanol are used in U.S. gasoline. Currently, ethanol comprises 10% of the U.S. gasoline pool (E10), but there is interest in increasing this – possibly doubling the amount currently used. Production of corn ethanol raises several concerns with respect to environmental and ecological impacts. This paper reviews the available literature regarding the impacts on water, soil, and air quality. A companion paper addresses issues of biodiversity, ecosystems, land use change, greenhouse gas (GHG) emissions, and sustainability. We emphasize recent information appearing since comprehensive reports on this topic were issued by the U.S. EPA and NRC/NAS in 2011.
... Ethanol blended fuels produce higher engine efficiency in addition to boosting fuel knock resistance. Improvement of engine performance has been observed under light load operations where knock resistance is not of significance [95,96]. Nakata et al. [20] identified the improved engine performance with different ethanol content of up to E50; the gain in efficiency was attributed to the decrease in combustion temperature and reduction in heat loss. ...
This study presents a lifecycle (well-to-wheel) analysis to determine the CO2 emissions associated with
ethanol blended gasoline in optimized turbocharged engines. This study provides a more accurate assessment
on the best-achievable CO2 emission of ethanol blended gasoline mixtures in future engines. The
optimal fuel blend (lowest CO2 emitting fuel) is identified. A range of gasoline fuels is studied, containing
different ethanol volume percentages (E0–E40), research octane numbers (RON, 92–105), and octane sensitivities
(8.5–15.5). Sugarcane-based and cellulosic ethanol-blended gasolines are shown to be effective
in reducing lifecycle CO2 emission, while corn-based ethanol is not as effective. A refinery simulation of
production emission was utilized, and combined with vehicle fuel consumption modeling to determine
the lifecycle CO2 emissions associated with ethanol-blended gasoline in turbocharged engines. The critical
parameters studied, and related to blended fuel lifecycle CO2 emissions, are ethanol content, research
octane number, and octane sensitivity. The lowest-emitting blended fuel had an ethanol content of 32 vol
%, RON of 105, and octane sensitivity of 15.5; resulting in a CO2 reduction of 7.1%, compared to the reference
gasoline fuel and engine technology. The advantage of ethanol addition is greatest on a per unit
basis at low concentrations. Finally, this study shows that engine-downsizing technology can yield an
additional CO2 reduction of up to 25.5% in a two-stage downsized turbocharged engine burning the optimum
sugarcane-based fuel blend. The social cost savings in the USA, from the CO2 reduction, is estimated
to be as much as $187 billion/year.
... Another important aspect is the reduction of the greenhouse gases (GHG) emissions involved in the use of bioethanol fuel. The lower carbon content per unit of volume and the type of source used during ethanol production causes, as a net effect, result in a lower emission of carbon dioxide, which is the major GHG from transport [4]. The main disadvantage is related to the lower vapour pressure of bioethanol, which makes a cold start of the engine difficult. ...
The objective of this study is to investigate the effect of bioethanol–gasoline blends on the exhaust emissions
and engine combustion of a four-stroke motorcycle. Ethanol is known as an alternative fuel for
spark-ignition engines and is suitable for making blends with gasoline, increasing the oxygen content
and decreasing emission of incomplete combustion products. An experimental investigation was performed
on a Euro 3 large-size motorcycle fuelled with commercial gasoline and bioethanol/gasoline
blends (range of bioethanol 5% v to 30% v). Regulated and unregulated emissions and fuel consumption
were quantified over the execution of chassis-dynamometer tests. The combustion analysis, realized by
acquiring the pressure cycle inside the cylinder, highlights the auto adjustment of the engine control unit
and guarantees use within the same parameters of several tested fuels, with the except of fuel injection
time, which increases with increasing ethanol percentage. A significant reduction in carbon monoxide
and particle number is associated with the ethanol content of the fuel. Volatile organic compounds,
mainly alkanes and aromatics, are not substantially influenced by the bioethanol content of the fuel.
The contribution of carcinogenic benzene ranges between 2 and 5%.
... Compared with internal combustion truck using oil-based fuels, the fuel consumption rate of alternative fuels and technology was evaluated based on energy rather than on volume because of the significantly different energy densities and vehicle efficiency [35]. The energy unit of this study is oil equivalent. ...
This paper proposed a COSM (cost-optimization superstructure model) and derived the optimized oil-saving pathways for road freight transportation in China until 2030. The optimization target of the COSM was to minimize the accumulated energy and vehicle costs from 2010 to 2030 by choosing the most cost-effective fuel option for newly registered trucks each year. Based on the COSM, three scenarios were developed to evaluate the oil-saving pathway in terms of imported crude oil price, available alternative fuels and GHG emission reduction. The scenario analysis results indicate that: (1) for scenario A, the accumulated oil-saving potential was approximately about 13%, while the oil-saving potential of improving fuel consumption rate and load running rate was 17% and 16%; (2) for scenario B, the accumulated oil-saving potential increased to 82% in reference oil price and 23% in low oil price; (3) for scenario C, to reduce per ton of GHG emission, the increased cost will increase from 34 USD to 450 USD when the GHG emission target decreased from 15.4 billion tons to the turn point of 13.5 billion tons.
... The net heating value of ethanol is also about one-third less than gasoline on a volumetric basis. While this difference reduces the volumetric fuel economy (miles per gallon), ethanol can provide a small improvement in the thermal efficiency of engine operation (miles per gallon of gasolineequivalent) [7]. ...
Biofuels, such as ethanol and butanol, have been the subject of significant political and scientific attention, owing to concerns about climate change, global energy security, and the decline of world oil resources that is aggravated by the continuous increase in the demand for fossil fuels. This study evaluated the potential emissions impacts of different alcohol blends on a fleet of modern gasoline vehicles. Testing was conducted on a fleet of nine vehicles with different combinations of ten fuel blends over the Federal Test Procedure and Unified Cycle. The vehicles ranged in model year from 2007-2014 and included four vehicles with port fuel injection (PFI) fueling and five vehicles with direct injection (DI) fueling. The ten fuel blends included ethanol blends at concentrations of 10%, 15%, 20%, 51%, and 83% by volume and iso-butanol blends at concentrations of 16%, 24%, 32%, and 55% by volume, and an alcohol mixture giving 10% ethanol and 8% iso-butanol in the final blend. The results showed some clear trends with increasing levels of alcohol in the blends for some pollutants, but not for others. There was a trend for lower CO, CO2, PM mass, and particle number, and lower fuel economy with higher alcohol content fuels. For other pollutants, such as THC, NMHC, CH4, and NOx, there were not strong fuel trends, while some carbonyl species showed some trends towards higher emissions for higher alcohol blends. The emissions profiles for the different vehicles also showed differences, with the wall-guided DI vehicles showing higher PM mass, and particle number compared to the PFI vehicles.
... However, there are several drawbacks with the use of ethanol as gasoline extender. These include ethanol's lower energy content (26.8 MJ/kg) compared to gasoline (42.7 MJ/kg), the increase in RVP (Reid vapor pressure), and the inability to transport it through pipelines due to risk of water-induced phase separation [12,13]. ...
We examined the effects of different ethanol and iso-butanol blends on the gaseous and particulate emissions from two passenger cars equipped with spark ignition direct injection engines and with one spray-guided and one wall-guided configuration. Both vehicles were tested over triplicate FTP (Federal Test Procedure) and UC (Unified Cycles) using a chassis dynamometer. Emissions of THC (total hydrocarbons), NMHC (non-methane hydrocarbons), and CO (carbon monoxide) reduced with increasing oxygen content in the blend for some of the vehicle/fuel combinations, whereas NOx (nitrogen oxide) emissions did not show strong fuel effects. Formaldehyde and acetaldehyde were the main carbonyls in the exhaust, with the higher ethanol blends showing higher acetaldehyde emissions during the cold-start. For butyraldehyde emissions, both vehicles showed some increases with different butanol blends when compared to ethanol blends, but not for all cases. The higher ethanol and butanol blends showed reductions in PM (particulate mass), number, and soot mass emissions. Particulate emissions were significantly affected by the fuel injection design, with the wall-guided vehicle producing higher mass and number emissions compared to the spray-guided vehicle. Particle size was influenced by ethanol and iso-butanol content, with higher alcohol blends showing lower accumulation mode particles than the baseline fuel.
... Ethanol is the world's most popular biofuel for use with existing spark-ignition (SI) engines. 1 In the U.S., the increase in ethanol use has been promoted by several legislative measures, including the Energy Independence and Security Act (EISA 2007) and the Renewable Fuel Standard (RFS), which was initiated in 2005 and expanded in 2007. 2 The latter mandates the use of 36 billion gallons of renewable fuels in the transportation fuel pool by 2022. Commercial U.S. gasoline contains ethanol at a concentration of 10% by volume (E10). ...
This study investigated the effects of higher ethanol blends and an iso-butanol blend on the criteria emissions, fuel economy, gaseous toxic pollutants, and particulate emissions from two flexible-fuel vehicles equipped with spark ignition engines, with one wall-guided direct injection and one port fuel injection configuration. Both vehicles were tested over triplicate Federal Test Procedure (FTP) and Unified Cycles (UC) using a chassis dynamometer. Emissions of non-methane hydrocarbons (NMHC) and carbon monoxide (CO) showed some statistically significant reductions with higher alcohol fuels, while total hydrocarbons (THC) and nitrogen oxides (NOx) did not show strong fuel effects. Acetaldehyde emissions exhibited sharp increases with higher ethanol blends for both vehicles, whereas butyraldehyde emissions showed higher emissions for the butanol blend relative to the ethanol blends at a statistically significant level. Particulate matter (PM) mass, number and soot mass emissions showed strong reductions with increasing alcohol content in gasoline. Particulate emissions were found to be clearly influenced by certain fuel parameters including oxygen content, hydrogen content, and aromatics content.
... Of these types, bioethanol -the focus of this study, is a biofuel extracted from agricultural products such as starch, sugars and lignocellulose, and is applied in blends with gasoline or diesel in order to reduce the dependency on petroleum and limit greenhouse exhaust emissions [7,[25][26][27][28][29]. Its global production has rapidly increased from 17 to 86 billion liters from 2000 and 2011 [30]. In Brazil and the US, which represent more than 90% of the total worldwide bioethanol production and consumption, the implementation of bioethanol has risen sharply in recent years [7,31], where Brazil has engaged in incentives and programs to engage at least 22% of the car and bus engines to run on hydrous bioethanol (96% bioethanol, 4% water) after the National Alcohol Fuel Program was established in 1975 [32]. ...
Thailand's sugarcane industry plays a key role in the nation's economy and agricultural sector, facing significant challenges including climate change, market fluctuations, and environmental concerns. To overcome these challenges, the industry is innovating through the development of drought-resistant sugarcane varieties and the adoption of precision agriculture techniques, aimed at enhancing yield and sustainability. Additionally, the sector is diversifying its output by venturing into the production of biofuels, bioplastics, and other bio-based materials, as well as high-value-added products for cosmetic and medical purposes. This strategic diversification is designed to reduce reliance on traditional sugar exports and foster new economic opportunities. Furthermore, the implementation of the Bio-Circular-Green (BCG) model policy is transforming the industry. This model facilitates the conversion of sugarcane into various valuable by-products, promoting resource efficiency and waste reduction. Emphasizing environmental stewardship, economic viability, and social responsibility, the BCG model ensures that the sugarcane industry remains a key to sustainable success of Thailand’s sustainable development strategy.
This study provides a summary about various motor vehicle models tested at the National Vehicle and Fuel Emissions Laboratory of the US Environmental Protection Agency (EPA), or tested by vehicle manufacturers with EPA’s oversight. The dataset contained 46,147 records (as of April 27, 2023) for many vehicle models, corresponding to model years between 1984 and 2024. A subset of the most-recent records in the dataset was analyzed here. This subset has 1357 records for model years 2023 and 2024. These records were divided into 6 groups based on the energy source(s) as 993 conventional gasoline-only, 193 unplugged hybrid electric, 113 battery electric, 22 diesel-powered, 20 plug-in hybrid, and 16 dual-fuel ethanol-gasoline. Averages of multiple performance metrics for each group were computed. These vehicle performance metrics help in identifying green vehicles releasing no (or little) tailpipe emissions, or in identifying economic vehicles conserving (paid) energy. Ten green vehicle metrics are covered here. The most important of them is the released grams of tailpipe carbon dioxide per kilometer of driving (or per mile). The overall average of this metric for all analyzed records was 231.0 gCO2/km (corresponding to 371.7 gCO2/mi). With a standard combined driving mode (55% city, 45% highway), 1 L of liquid fuel (gasoline/petrol, diesel, or E85 ethanol-gasoline blend) or a standard equivalent electric energy of 8.90 kWh (32.0 MJ) is consumed by an average vehicle for traveling a distance of 12.4 km (corresponding to 29.3 miles per US gallon of gasoline-equivalent, or MPGe).
div>Greenhouse gas emissions reduction from the light-duty transportation fleet is urgent and should address both electric and conventional powertrain technologies. Internal combustion engines will continue to be employed for vehicle propulsion and fleet turnover is slow, encouraging reduction of carbon content in gasoline. Currently ethanol, a renewable fuel, is blended at the 10% level into petroleum to produce finished market gasoline. Ethanol enables a less carbon-intensive petroleum blendstock composition, providing for additional reduction, but this is often overlooked in studies. Carbon intensity, as a ratio of CO2 mass to heat released upon combustion, is a measure of well-to-wheels greenhouse gas production. The well-to-wheels carbon intensity of ethanol does not include its chemical carbon content because it arises from a renewable source, but does consider all upstream farming, production, and transportation carbon impacts. The well-to-wheels carbon intensity of the petroleum fraction includes the chemically bound carbon, as well as production and transportation impact. Carbon intensity modeling results for ethanol vary widely, primarily due to differences in land-use change assessment. The GREET model has gained wide acceptance and provides a present-day carbon intensity for pure ethanol that is 43% lower than for petroleum gasoline. Ethanol exhibits a high blending octane number so that the petroleum component has a lower octane rating than required for purely petroleum gasoline. Fuel trends and modeling suggest that a 10% (by volume) ethanol addition enables a 9% reduction of aromatics, which have a high carbon intensity. If the carbon reduction benefits of the aromatic reduction are assigned to the agency of the ethanol, the blending carbon intensity of ethanol is 56% lower than for petroleum gasoline. Increase in ethanol blending therefore offers substantial immediate climate change reduction.</div
Rising the concern of energy security and the instability in fossil fuels price in addition to the adverse effect of these fossil fuels on the environment, made the world searching for alternative energy sources that are sustainable and clean to the environment. One of these alternative energies is bioethanol. Bioethanol is produced by microbial fermentation either from sugar crops or starchy grain crops depending on their availability as first-generation carbon sources for bioethanol production. These carbon sources are edible in nature and could lead into food-vs-fuel conflict and famine specially in developing countries. Inedible lignocellulosic biomass such as abundant agriculture byproducts and forestry waste are developed as second-generation carbon sources for bioethanol production. However so far, the excessive production cost of bioethanol from these lignocellulosic biomasses limiting the application of this technology for commercialization on large scale. In addition to the first and second generations of bioethanol technologies, there is third generation of carbon sources that currently under investigation for bioethanol production by gasification a wide verities of biomass sources into syngas (SG). Syngas is a mixture of carbondioxide, carbon monoxide, and hydrogen. This syngas can be utilized as acarbon source for microbial fermentation using anaerobic bacteria such as Clostridium sp. to convert syngas into bioethanol and organic acids. In general,the interest in bioethanol as an alternative energy to fossil oil is due to its favorable properties as energy source.
This study presents the way to use renewable fuel like ethanol in its hydrous form. The higher cost required for anhydrous ethanol production beyond the azeotropic point is the need to use ethanol in the hydrous form. As ethanol can be produced from a renewable energy source using various bio-mass, many countries are targeting to increase ethanol usage as fuel. Specific methods for using hydrous ethanol in SI and CI engines are discussed. Blending hydrous ethanol with gasoline and diesel using various additives is a good alternative for using biofuel-like ethanol in its hydrous form. Combustion techniques like (GPI+EDI), HCCI, RCCI, and PCCI have incorporated hydrous ethanol, reducing harmful emissions like NOx and Soot with good energy conversion efficiency. Using hydrous ethanol as an engine fuel has shown reasonable cost savings in countries like the USA, India, and Brazil.
Ethanol, an alternative fuels based on alcohol for spark ignition engines, can be used by mixing with gasoline at the proper ratios, and which reducing exhaust emissions by an increase in oxygen content. Although there are many studies conducted on the use of ethanol in internal combustion engines, no studies have been conducted on the use of ethanol in two-stroke uniflow gasoline engines so far. In this experimental study, performance, emission and combustion characteristics of ethanol/gasoline blends (range of ethanol 10% v–50% v) were examined in a two-stroke uniflow gasoline engine at 1800 1/min and full load. In cylinder pressures, heat release rates, mass fraction burnt, engine torque, break specific fuel consumptions, delivery ratio, scavenging efficiency, carbon monoxide (CO), hydrocarbon (HC), carbon dioxide (CO2) and nitrogen oxides (NOx) emissions were investigated. The combustion phasing was advanced after adding ethanol due to the higher burning velocity. Delivery ratio and scavenging efficiency have increased due to the faster evaporation of ethanol than gasoline. Break thermal efficiency (BTE) decreased because of the decreased net work, and break specific fuel consumption (BSFC) increased because ethanol had lower heating value (LHV) than gasoline. CO, HC, CO2 and NOx emissions decreased with the increase in the ethanol content in gasoline.
Particulate matter (PM), oxides of nitrogen (NOx), carbon monoxide (CO), and total hydrocarbons (THC) in gasoline exhaust affect atmospheric quality, and hence human health. Ethanol produced from corn grain is a renewable resource with favorable anti-knock properties for gasoline blending. Refiners alter petroleum composition to produce a finished blend that meets specifications. Ethanol blending affects emissions from market fuels both directly and indirectly since aromatics are typically removed from the BOB as ethanol is added to reach a constant octane rating. Numerous studies have been conducted to assess the effect of ethanol blending on light duty vehicle emissions. However, few studies have examined market fuel blends directly and small studies yield insufficient information to be generally applicable. If blending of fuels for a study does not yield gasoline that adequately resembles the composition of a market blend, the generalizability of study results may be impacted by nonlinear blending effects. Most vehicle-based fuel effect studies employed fuel formulations that either facilitate examination of several fuel variables or blend ethanol into a baseline gasoline (splash blending). Such study results do not support direct quantification of emissions inventory effects. To examine real world blending implications on regulated emissions [PM, NOx, CO, THC], we compiled a comprehensive database of US emission studies, developed regression models based on fuel and vehicle properties, and used those models to estimate differences in emissions from expected market fuel compositions. We addressed nonlinear responses to ethanol composition by modeling both low (up to 10% ethanol by volume) and mid blends. We used the Federal Test Procedure (FTP) and Unified Cycle (LA92) driving schedule data, with the cold-start eliciting the highest emissions. PM cold-start emissions were lower with higher ethanol content, and more so at higher blend levels but hot-running emissions showed no differences with respect to ethanol level. For NOx, CO and THC emissions, the effects differed between port fuel injection (PFI) and gasoline direct injection (GDI) powered vehicles and split models. NOx results varied over blend levels and THC results were scattered for the higher blends. CO emissions were lower with higher ethanol content in nearly all cases for PFI but only the hot-running GDI. Results did not differ between summer regular and premium fuels. To the extent that PFI and GDI models differ, an emissions inventory calculation should treat them separately. There is uncertainty directly associated with the regression process, and with model inputs since study methods vary and compositions are reported differently between laboratories and test methods. Small changes in modeled emissions should be considered in this light.
Hydrous ethanol has lower cost and energy consumption during the production process than anhydrous ethanol. Many researchers used hydrous ethanol instead of anhydrous ethanol to manufacture hydrous ethanol-gasoline. The water ratio in hydrous ethanol (ω) determines the energy consumption in the production process of ethanol. However, no one researched the effects of different ω on combustion and emissions of hydrous ethanol-gasoline. So, we prepared five kinds of ethanol with different ω (0, 5%, 10%, 15%, 20% vol.) to research the effects of ω on combustion and emissions. This study adopted combined injection with hydrous ethanol direct injection plus gasoline port injection (HEDI + GPI). The engine speed was 1500 rpm, and λ was 1, the intake manifold absolute pressure was 48 kPa, the direct injection ratio was 20%, five spark timings varied from 5 °CA BTDC to 25 °CA BTDC. The results showed hydrous ethanol prolonged flame development and propagation duration, decreased Tmax and Pmax, delayed APmax. Water increased COVimep, but using hydrous ethanol at the reasonable spark timing would not significantly affect the stability. Meanwhile, when the spark timing was MBT, compared with GE (gasoline/anhydrous ethanol dual fuel) fuel, as ω in GEW (gasoline/hydrous ethanol dual fuel) fuels increased, torque and brake thermal efficiency improved by 1.69%, 1.13%, −0.01%, −0.77%; HC increased by 2.13%, 9.02%, 23.89%, 37.15%; CO decreased by 41.95%, 28.56%, 5.59%, 2.46%; NOx decreased by 10.10%, −0.75%, −0.17%, 4.18%; total PN emissions decreased by 24.07%, 69.57%, 36.34%, 32.45%. Meanwhile, more water caused the size of particles to drop, made particles smaller.
Life cycle impact assessment (LCIA) is a lively field of research, and data and models are continuously improved in terms of impact pathways covered, reliability, and spatial detail. However, many of these advancements are scattered throughout the scientific literature, making it difficult for practitioners to apply the new models. Here, we present the LC‐IMPACT method that provides characterization factors at the damage level for 11 impact categories related to three areas of protection (human health, ecosystem quality, natural resources). Human health damage is quantified as disability adjusted life years, damage to ecosystem quality as global species extinction equivalents (based on potentially disappeared fraction of species), and damage to mineral resources as kilogram of extra ore extracted. Seven of the impact categories include spatial differentiation at various levels of spatial scale. The influence of value choices related to the time horizon and the level of scientific evidence of the impacts considered is quantified with four distinct sets of characterization factors. We demonstrate the applicability of the proposed method with an illustrative life cycle assessment example of different fuel options in Europe (petrol or biofuel). Differences between generic and regionalized impacts vary up to two orders of magnitude for some of the selected impact categories, highlighting the importance of spatial detail in LCIA.
The intrinsic kinetic behaviour of catalytic hydrogenation of acetic acid in vapour phase was studied over a multi-metallic catalyst. The rate expression was derived from the sequence of elementary reaction steps based on a Langmuir-Hinshelwood-model involving two types of active sites. Experiments were carried out in a fixed bed reactor, which is similar to an isothermal integral reactor designed to excluding the negative effects of internal and external diffusion. The reaction conditions investigated were as follow:reaction temperature 275-325 ºC, reaction pressure1.5-3.0 MPa, liquid hourly space velocity (sv) 0.3-1.2 h-1, molar ratio of hydrogen to acetic acid (H/AC) 8:20. The results show that conversion of acetic acid increases with increasing the reaction temperature and pressure, but decreases with increasing the space velocity and H/AC. Furthermore, reducing the reaction pressure and increasing reaction temperature, space velocity and H/AC can improve the reaction selectivity of acetic acid to ethanol. The established kinetic model results agreed with experimental results. The relative difference between the calculated value and the experimental value is less than 6 %. The values of model parameters are consistent with the three thermodynamic constraints. The study provided evidence that the intrinsic kinetic model is suitable both mathematically and thermodynamically, and it could be useful in guiding reactor design and optimization of operating conditions.
In this paper, a sensor structure operating in the microwave frequency band is used and it is aimed to determine whether fuel samples are branded or not. In the literature, the studies on the sensor applications of metamaterials (MTMs) have increased considerably in recent years. However, this study, unlike other studies, focuses on determining the changes in electromagnetic parameters of different fuel samples at X band frequencies. For this purpose, the electromagnetic properties of the branded and unbranded fuel samples are measured experimentally. Then, simulation studies are carried out using the experimental results and the dimensions of the resonators are optimized to determine the most suitable structure. Fabrication of MTM sensor structure is then performed using optimized dimensions. Finally, the experimental study is carried out using the sensor structure.
It is of a great challenge to develop semiconductor photocatalysts with potential possibilities to simultaneously enhance photocatalytic efficiency and inhibit generation of toxic intermediates. In this study, we developed a facile method to induce the La doping and cationic vacancie (VZn) on ZnO for the highly efficient complete NO oxidation. The photocatalytic NO removal efficiency increases from 36.2% to 53.6%. Most importantly, a significant suppressed NO2 production also has been realized. According to the DFT calculations, ESR spectra and in situ FTIR spectra, the introduction of La³⁺ induce the redistribution of charge carriers in La-ZnO, which promote the production of O2⁻ and lead to the formation of VZn for the formation of OH, contributing to the complete oxidation of NO to nitrate. Besides, the conversion pathway of photocatalytic NO oxidation has been elaborated. This work paves a new way to simultaneously realize the photocatalytic pollutants removal and the inhibition of toxic intermediates generation for efficient and safe air purification.
In this work, we report a metal-organic framework (MOF)-assisted strategy to synthesize necklace-like TiO2/Co3O4 nanofibers with highly ordered heterostructures via a facile approach including electrospinning and subsequent calcination. Polycrystalline TiO2 nanofiber and MOF-derived Co3O4 nanocage are consummate interconnected to form highly ordered heterogeneous nanostructure, which can be benefit for precisely accommodating the interface resistance of the p-n heterojunctions and future realization of improved materials performance. The ethanol gas-sensing investigation showed that TiO2/Co3O4 NFs sensors exhibited 4-fold higher ethanol response (Rair/Rgas -1 = 16.7 @ 150 ppm) and a relatively lower operating temperature of 150 °C. The sensing enhancement mechanism of the TiO2/Co3O4 NFs is related to the formation of heterojunction at interfaces and the high catalytic activity of MOF-derived Co3O4. Furthermore, this versatile method is a promising approach to construct ordered heterostructures and extend the MOF-based heterogeneous materials toward wide applications.
Vapor-phase dehydrogenation of ethanol to acetaldehyde was studied using Cu/SiO2 and ZnO/SiO2 catalysts prepared by the conventional impregnation method. Catalysts were characterized by XRD, nitrogen adsorption-desorption analysis, XPS, N2O-pulse method, CO2-TPD and C2H5OH-TPD. Use of copper ammonium complex for the preparation of Cu/SiO2 catalysts formed Cu particles on SiO2 too small for detection by XRD. The prepared Cu/SiO2 catalyst had high and selective dehydrogenation activity of ethanol to acetaldehyde. However, Cu/SiO2 catalyst was less stable at 350 °C due to sintering of Cu. Interestingly, a metal oxide catalyst, ZnO/SiO2, had fairly high and fully selective activity for dehydrogenation of ethanol to acetaldehyde. Furthermore, no changes in the activity and selectivity were observed for at least 6 h at 350 °C. The reaction pathways on the metal catalyst, Cu/SiO2, and the oxide catalyst, ZnO/SiO2, were studied by C2H5OH-TPD. Evolution of H2 was observed from ethanol contacted with Cu/SiO2 catalyst at 50 °C, suggesting dehydrogenation at this temperature. Desorption of acetaldehyde was observed above 200 °C. On the other hand, simultaneous desorption of H2 and acetaldehyde occurred on ZnO/SiO2 catalyst above 240 °C, suggesting that the rate determining step is the dissociative adsorption of ethanol at this temperature. Thus, the reaction pathways were very different for the metal catalyst and the oxide catalyst.
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The EU Consumer Footprint aims at assessing the environmental impacts of consumption. The methodology for assessing the impacts is based on the life cycle assessment (LCA) of products (or services) purchased and used in one year by an EU citizen. This report is about the subset indicator of the consumer footprint of the basket of product (BoP) on mobility. The baseline model of the BoP mobility is built using statistics about European fleet composition and intensity of use of transport means by European citizens, i.e. the number of kilometers travelled by road, rail and air transport. These data are then allocated to 27 representative products, including 16 types of passenger cars, 3 types of 2-wheelers, 3 types of bus transport, 2 types of rail transport and 3 types of air transport.
The resulting baseline inventory model, referring to the year 2010, has been assessed for 15 different impact categories, using the ILCD life cycle impact assessment method. A sensitivity analysis has been run for some impact categories, with a selection of recent impact assessment models and factors. Results allows a wide array of considerations, as this study reports overall impact in Europe due to mobility, average impact per citizen, share of impact due to each transport mode and type of vehicle. The results highlight that road transport is by far the mode of transport contributing the most to the impact of EU citizens’ mobility. Within this macro-category, the product groups that can be considered hotspots for the European mobility are passenger cars, and especially diesel cars. In terms of impact categories, resource depletion is the most important one, especially for road transport (due to the materials used to build the vehicles and the fossil fuels used in the use stage). The contribution of life cycle stages to the overall impact of the BoP mobility varies among impact categories: vehicle usage, fuel production and vehicle production are the most relevant stages for almost all the impact categories considered.
To assess potential benefits stemming from selected ecoinnovations applied to the mobility sector, the Consumer Footprint BoP mobility baseline has been assessed against five scenarios. The scenarios developed for the BoP mobility regard the use of eco-driving measures (including technical and behavioural changes), an increased use of biofuels in substitution of the current blend of diesel, and the evolution of hybrid and electric mobility (as the share of hybrid and electric vehicles in the European fleet and of the expected increase in efficiency of the batteries). In addition, one scenario is directly related to changes in the lifestyle of European citizens, namely the shift of a portion of their mobility habits from private cars to public transport, for what concern the mobility in urban areas.
The amount of km travelled yearly by European citizens plays a relevant role in the assessment of the scenarios representing possible improvement options for the sector. Indeed, the number of person*km (pkm) travelled yearly by an average European citizen is constantly growing over time. This is reflected in the larger impact (over all the impact categories considered) of the baseline for the reference year 2015 over the baseline 2010 and of scenario 1 (expected situation in 2030) over the baselines 2015 and 2010. The increase of the pkm travelled offsets the reduction of the impact per km travelled achieved through the introduction of cars compliant to the new emission standards (Euro 6) and through the increase of electric and hybrid vehicles. The expected improvements related to electric and hybrid cars, and especially on the batteries, could lead to a reduction of the impact of these type of vehicles up to 40% (e.g. impact of improved electrical vehicle on freshwater eutrophication, compared to the current performance of electrical vehicle). However, the relevance of these improvements on the overall impact of the BoP (i.e. of the mobility of EU citizens) is strongly dependent on the share of vehicles in the fleet. In general, the impact reduction expected from the single solutions tested in the scenarios has a limited effect on the overall impact of the BoP (i.e. of the consumption area of mobility) if they are considered one by one and it is the combination of several measures that may help to maximize the benefits. Specifically for the mobility sector, a reduction of the total kms travelled by road, rail or air means of transport (e.g. by increasing the kms travelled by bicycle or by walking, when possible), is needed, to avoid that the reduction of impact achieved through technological improvements is offset by the continuous increase in the amount of pkm over time.
United States federal regulations require increasing renewable fuel blending in the transportation sector, a majority of which is corn ethanol. Nationally, ethanol is blended with gasoline up to 10% (E10) for use in conventional vehicles, and up to 85% (E85) for use in flexible fuel vehicles (FFVs). Meeting the blending requirements could mean increasing the ethanol blended with gasoline or E85 use in FFVs. The authors estimate costs typically not quantified for FFV drivers refueling with E85, which are a small component of total costs, and consider the infrastructure costs to expand E85 access in Pennsylvania. Even with a retailer incentive of 0.39=gasoline liter equivalent (gle) to encourage ethanol infrastructure installation, an E85 consumer would still also experience higher refueling costs. A E85 consumer refueling and convenience cost of 1,320=metric ton CO2 is 36 times larger than the average U.S. social cost of carbon (CO2) for 2015.
The ecotoxicity of solutions stemming from Direct Ethanol Fuel Cells (DEFC) has decreased after the electrooxidation process, when amorphous electrodes are used. This decrease is a function of the applied potential and the electrode composition. Ethanol and Bioethanol electrooxidation take place after a sequence of reactions, in which intermediate products are formed and they can affect the general process of alcohol electrooxidation. Bioethanol has been investigated as an alternative fuel for DEFC, but it behaves differently to ethanol in the electrooxidation process. Different results have been obtained in ethanol and bioethanol electrooxidation.
The ecotoxicity of solutions stemming from Direct Ethanol Fuel Cells (DEFC) has decreased after the electrooxidation process, when amorphous electrodes are used. This decrease is a function of the applied potential and the electrode composition. Ethanol and Bioethanol electrooxidation take place after a sequence of reactions, in which intermediate products are formed and they can affect the general process of alcohol electrooxidation. Bioethanol has been investigated as an alternative fuel for DEFC, but it behaves differently to ethanol in the electrooxidation process. Different results have been obtained in ethanol and bioethanol electrooxidation.
Light-duty vehicles (LDVs) in the United States and elsewhere are required to meet increasingly challenging regulations on fuel economy and greenhouse gas (GHG) emissions as well as criteria pollutant emissions. New vehicle trends to improve efficiency include higher compression ratio, downsizing, turbocharging, downspeeding, and hybridization, each involving greater operation of spark-ignited (SI) engines under higher-load, knock-limited conditions. Higher octane ratings for regular-grade gasoline (with greater knock resistance) are an enabler for these technologies. This literature review discusses both fuel and engine factors affecting knock resistance and their contribution to higher engine efficiency and lower tailpipe CO2 emissions. Increasing compression ratios for future SI engines would be the primary response to a significant increase in fuel octane ratings. Existing LDVs would see more advanced spark timing and more efficient combustion phasing. Higher ethanol content is one available option for increasing the octane ratings of gasoline and would provide additional engine efficiency benefits for part and full load operation. An empirical calculation method is provided that allows estimation of expected vehicle efficiency, volumetric fuel economy, and CO2 emission benefits for future LDVs through higher compression ratios for different assumptions on fuel properties and engine types. Accurate "tank-to-wheel" estimates of this type are necessary for "well-to-wheel" analyses of increased gasoline octane ratings in the context of light duty vehicle transportation.
We commend Yan et al. for compiling and synthesizing a collection of literature that addresses the nuanced influence that blending ethanol into gasoline can have on the fuel economy of spark ignition (SI) engines, which affects the life-cycle GHG emissions of the blended fuel. As biofuel policies are often motivated by the goal of reducing petroleum demand, the proposed effective substitution ratio (ESR) is a simple metric for quantifying the petroleum fuel displacement value that alternative fuels currently do and potentially can offer.
The authors collected, filtered, and analyzed a vast multidimensional array of data from dozens of different studies, with varying degrees of controls and transparent reporting of experimental conditions, for the purpose of drawing conclusions that may be generally applicable to the ESR of the U.S. fleet. However, we would like to draw attention to several major weaknesses within the paper by Yan et al., which relate to the authors’ assertion of novel energy-centric recommendations, decision to omit Brazilian engine studies, choice of statistical analyses, and interpretation of results. We conclude by providing an alternate interpretation of the results and expanding upon the authors’ recommendations for future work. . .
Despite the incredible growth of the U.S. ethanol industry, the United States is struggling to meet Renewable Fuel Standard (RFS2) targets. In addition to the challenge of producing ethanol at cost that is competitive with petroleum gasoline, an additional expense emanates from enabling its consumption as the US fuel market encounters the ‘blend wall.’ That is, common gasoline sold in the contiguous United States now contains 10% ethanol by volume—the maximum blend acceptable for use in existing infrastructure and vehicles. Without 1) rapid technological innovation in drop-in biofuel production, 2) increased tolerance of ethanol blends in existing infrastructure and vehicle standards, or 3) revision of the RFS2 to become production-focused instead of consumption-focused, options for increasing the functional blend wall beyond E10 must come from a) increased in consumption of mid- to high- level ethanol-gasoline blends such as E30 or E85, and/or b) increased E15 consumption among operators of vehicles manufactured in 2001 or later. We highlight a few key challenges to enabling greater ethanol consumption in an economically and environmentally efficient manner, on a national and global scale. We identify research, deployment, and policy opportunities to improve global fuel system energy and GHG efficiency, and review economic and emissions trade-offs associated with technically feasible options to meet this challenge.
Lifecycle analysis (LCA) metrics of greenhouse gas emissions are increasingly being used to select technologies supported by climate policy. However, LCAs typically evaluate the emissions associated with a technology or product, not the impacts of policies. Here, we show that policies supporting the same technology can lead to dramatically different emissions impacts per unit of technology added, due to multimarket responses to the policy. Using a policy-based consequential LCA, we find that the lifecycle emissions impacts of four US biofuel policies range from a reduction of 16.1 gCO2e to an increase of 24.0 gCO2e per MJ corn ethanol added by the policy. The differences between these results and representative technology-based LCA measures, which do not account for the policy instrument driving the expansion in the technology, illustrate the need for policy-based LCA measures when informing policy decision making.
Most prior studies have found that substituting biofuels for gasoline will reduce greenhouse gases because biofuels sequester
carbon through the growth of the feedstock. These analyses have failed to count the carbon emissions that occur as farmers
worldwide respond to higher prices and convert forest and grassland to new cropland to replace the grain (or cropland) diverted
to biofuels. By using a worldwide agricultural model to estimate emissions from land-use change, we found that corn-based
ethanol, instead of producing a 20% savings, nearly doubles greenhouse emissions over 30 years and increases greenhouse gases
for 167 years. Biofuels from switchgrass, if grown on U.S. corn lands, increase emissions by 50%. This result raises concerns
about large biofuel mandates and highlights the value of using waste products.
Greenhouse gases, regulated emissions, and energy use in transportation (GREET) excel model has been developed by Argonne National Labs for estimating the full fuel-cycle energy and emission impacts of various transportation fuels and vehicle technologies. It calculates fuel-cycle energy use in Btu/mi and emissions in g/mi for various transportation fuels and vehicle technologies. For energy use, GREET includes total energy use (all energy sources), fossil energy use (petroleum, natural gas, and coal), and petroleum use. For emissions, the model includes three major greenhouse gases (CO2, CH4, and N2O), and five criteria pollutants (VOC, CO, NOx, particulate matter with a diameter of ≤ 10 micrometers, and SOx). A stochastic simulation tool was developed to simplify setting up and executing a stochastic simulation for any Excel model. This tool was applied to the GREET model and compared the performance of the sampling techniques for selected output variables with different number of samples. This is an abstract of a paper presented at the AIChE Annual Meeting (San Francisco, CA 11/12-17/2008).
Biofuels are increasingly promoted worldwide as a means for reducing greenhouse gas (GHG) emissions from transport. However, current regulatory frameworks and most academic life cycle analyses adopt a deterministic approach in determining the GHG intensities of biofuels and thus ignore the inherent risk associated with biofuel production. This study aims to develop a transparent stochastic method for evaluating UK biofuels that determines both the magnitude and uncertainty of GHG intensity on the basis of current industry practices. Using wheat ethanol as a case study, we show that the GHG intensity could span a range of 40–110 gCO2e MJ−1 when land use change (LUC) emissions and various sources of uncertainty are taken into account, as compared with a regulatory default value of 44 gCO2e MJ−1. This suggests that the current deterministic regulatory framework underestimates wheat ethanol GHG intensity and thus may not be effective in evaluating transport fuels. Uncertainties in determining the GHG intensity of UK wheat ethanol include limitations of available data at a localized scale, and significant scientific uncertainty of parameters such as soil N2O and LUC emissions. Biofuel polices should be robust enough to incorporate the currently irreducible uncertainties and flexible enough to be readily revised when better science is available.
The search for alternative fuels to alleviate our dependency on fossil-based transportfuels is driven by depleting conventional oil resources and looming climate change induced by anthropogenic greenhouse gas (GHG) emissions. Through a lifecycle approach, we evaluate whether algal biodiesel production can be a viable fuel source once the energy and carbon intensity of the process is managed accordingly. Currently, algae biodiesel production is 2.5 times as energy intensive as conventional diesel and nearly equivalent to the high fuel-cycle energy use of oil shale diesel. Biodiesel from advanced biomass can realise its inherent environmental advantages of GHG emissions reduction once every step of the production chain is fully optimized and decarbonised. This includes smart co-product utilization, decarbonisation of the electricity and heat grids as well as indirect energy requirements for fertilizer, transport and building material. Only if all these factors are taken into account is the cost of heat and electricity reduced, and GHG emissions fully mitigated.
In support of the U.S. Department of Energy's development and deployment of alternative fuels for environmental and national security reasons, NREL has managed a series of light-duty vehicle emissions tests on alternative fuel vehicles (AFVs). The purpose of this report is to give a detailed evaluation of the final emissions test results on vehicles tested on methanol, ethanol, and compressed natural gas.
This report reviews the use of higher alcohols and several cellulose-derived oxygenates as blend components in gasoline. Material compatibility issues are expected to be less severe for neat higher alcohols than for fuel-grade ethanol. Very little data exist on how blending higher alcohols or other oxygenates with gasoline affects ASTM Standard D4814 properties. Under the Clean Air Act, fuels used in the United States must be 'substantially similar' to fuels used in certification of cars for emission compliance. Waivers for the addition of higher alcohols at concentrations up to 3.7 wt% oxygen have been granted. Limited emission testing on pre-Tier 1 vehicles and research engines suggests that higher alcohols will reduce emissions of CO and organics, while NOx emissions will stay the same or increase. Most oxygenates can be used as octane improvers for standard gasoline stocks. The properties of 2-methyltetrahydrofuran, dimethylfuran, 2-methylfuran, methyl pentanoate and ethyl pentanoate suggest that they may function well as low-concentration blends with gasoline in standard vehicles and in higher concentrations in flex fuel vehicles.
Ethanol offers significant potential for increasing the compression ratio of SI engines resulting from its high octane number and high latent heat of vaporization. A study was conducted to determine the knock limited compression ratio of ethanol gasoline blends to identify the potential for improved operating efficiency. To operate an SI engine in a flex fuel vehicle requires operating strategies that allow operation on a broad range of fuels from gasoline to E85. Since gasoline or low ethanol blend operation is inherently limited by knock at high loads, strategies must be identified which allow operation on these fuels with minimal fuel economy or power density tradeoffs. A single cylinder direct injection spark ignited engine with fully variable hydraulic valve actuation (HVA) is operated at WOT conditions to determine the knock limited compression ratio (CR) of ethanol fuel blends. The geometric compression ratio is varied by changing pistons, producing CR from 9.2 to 13.66. The effective CR is varied using an electro-hydraulic valvetrain that changed the effective trapped displacement using both Early Intake Valve Closing (EIVC) and Late Intake Valve Closing (LIVC). The EIVC and LIVC strategies result in effective CR being reduced while maintaining the geometric expansion ratio. It was found that at substantially similar engine conditions, increasing the ethanol content of the fuel results in higher engine efficiency and higher engine power. These can be partially attributed to a charge cooling effect and a higher heating valve of a stoichiometric mixture for ethanol blends (per unit mass of air). Additional thermodynamic effects on and a mole multiplier are also explored. It was also found that high CR can increase the efficiency of ethanol fuel blends, and as a result, the fuel economy penalty associated with the lower energy content of E85 can be reduced by about a third. Such operation necessitates that the engine be operated in a de-rated manner for gasoline, which is knock-prone at these high CR, in order to maintain compatibility. By using EIVC and LIVC strategies, good efficiency is maintained with gasoline, but power is reduced by about 34%.
Due to worldwide concern regarding green house gases emission, mainly CO 2, automakers are developing new technologies to reduce vehicles fuel consumption. One of the most promising technologies, growing fast in USA, Japan and Europe are the Hybrid Electric Vehicles (HEVs). In the Brazilian Market, HEVs availability is still absent, which causes uncertainties about possible impacts caused by the introduction of this new vehicle technology in the big cities. However, as requirements of non-pollutant technologies arise, HEVs are expected to be available in Brazilian Market in the next years. Within this scenario, in 2002, aiming to evaluating the adequacy of Brazilian Gasolines blended with up to 25% v/v of Ethanol in HEV technology, Petrobras Research and Development Center (CENPES) purchase from USA a 2002 Toyota Prius and a 2002 Honda Insight. Since them, both HEVs are being tested at CENPES's Vehicle Test Laboratory (LEV). This paper will present topics related to HEV technology evolution, future trends, governmental benefits offered for these vehicles in some countries. Additionally, noticeable advantages and disadvantages of this technology in the world market are highlighted. It will also present CENPES experience with HEVs, including the methodology evolution required for laboratory tests with HEVs and the preliminary emission and fuel economy test results obtained with Brazilian Super Premium Gasoline - less than 30 ppm of Sulfur content - blended with 25% v/v of Ethanol in a 2002 Toyota Prius and a 2002 Honda Insight HEVs.
This study examines the effects of ethanol content on engine performances and the knock characteristics in spark ignition gasoline engine under various compression ratio conditions by cylinder pressure analysis, visualization and numerical simulation. The results confirm that increasing the ethanol content provides for greater engine torque and thermal efficiency as a result of the improvement of knock tolerance. It was also confirmed that increasing the compression ratio together with increasing ethanol content is effective to overcome the shortcomings of poor fuel economy caused by the low calorific value of ethanol. Further, the results of one dimensional flame propagation simulation show that ethanol content increase laminar burning velocity. Moreover, the results of visualization by using a bore scope demonstrate that ethanol affects the increase of initial flame propagation speed and thus helps suppress knock.
In this study the fuel influence of several bio-fuel candidates on homogeneous engine combustion systems with direct injection is investigated. The results reveal Ethanol and 2-Butanol as the two most knock resistant fuels. Hence these two fuels enable the highest efficiency improvements versus RON95 fuel ranging from 3.6 % -12.7 % for Ethanol as a result of a compression ratio increase of 5 units. Tetrahydro-2-methylfuran has a worse knock resistance and a decreased thermal efficiency due to the required reduction in compression ratio by 1.5 units. The enleanment capability is similar among all fuels thus they pose no improvements for homogeneous lean burn combustion systems despite a significant reduction in NO X emissions for the alcohol fuels as a consequence of lower combustion temperatures. In general, 1-Butanol and 2-Butanol emit higher amounts of HC emissions in all operation points combined with significantly increased particle emissions at high loads indicating a worse mixture formation. Alcohol fuels lead under cold conditions to a higher oil dilution which is significantly depending on the boiling temperature of the fuel. Hence, the usage of 1-Butanol as a pure fuel is critical.
Ford Motor Company is introducing "EcoBoost" gasoline turbocharged direct injection (GTDI) engine technology in the 2010 Lincoln MKS. A logical enhancement of EcoBoost technology is the use of E85 for knock mitigation. The subject of this paper is the optimal use of E85 by using two fuel systems in the same EcoBoost engine: port fuel injection (PFI) of gasoline and direct injection (DI) of E85. Gasoline PFI is used for starting and light-medium load operation, while E85 DI is used only as required during high load operation to avoid knock. Direct injection of E85 (a commercially available blend of ~85% ethanol and ~15% gasoline) is extremely effective in suppressing knock, due to ethanol's high inherent octane and its high heat of vaporization, which results in substantial cooling of the charge. As a result, the compression ratio (CR) can be increased and higher boost levels can be used. The increased full load BMEP allows downsizing of the engine at equivalent or enhanced vehicle performance. By enabling higher CR and engine downsizing, the use of E85 DI + gasoline PFI makes the engine more efficient in its use of gasoline, thereby leveraging the effect of the available ethanol in reducing the consumption of gasoline. This leveraging has a profound influence on ethanol's net energy balance and CO2 reduction potential. The vehicle owner will realize high fuel economy because gasoline, with its high heating value per volume, is primarily used for most driving modes in a downsized, high CR engine. In this paper, the concept of E85 DI + gasoline PFI is assessed using a Ford Motor Company 3.5L turbocharged direct injection EcoBoost engine. A PFI system was added to the engine and CR was increased to 12:1. The amount of E85 required to avoid knock was quantified as a function of BMEP at various engine speeds on an engine dynamometer. A full load torque curve subject to the peak pressure and turbine inlet temperature constraints of the engine was also acquired. A vehicle simulation program was then used to quantify the amount of E85 required for various drive cycles, and to determine vehicle fuel consumption.
Flexible fuel vehicle production has been steadily increasing in the US over the past fifteen years. Ethanol is considered a renewable fuel additive to gasoline which helps the US efforts in minimizing the dependency on foreign oil. As a result, it is becoming very hard to find pure gasoline which does not contain some ethanol content at the pump in the US. The fuel currently available at the pump contains close to 10% ethanol. The fuel and evaporative systems components and materials on newer flexible fuel vehicles are being designed to be tolerant of the 10% ethanol content. There is a strong desire from ethanol producers to increase the ethanol content up to a 20% level. This is still being debated by the Environmental Protection Agency and a final decision has not been made yet but will be announced by the upcoming Tier 3 Notice of Public Rule Making (NPRM) in December of 2011. Early signs from EPA are indicating that E15 would be the official certification fuel with the upcoming Tier 3 NPRM. The California Air Resources Board (CARB) proposed in the LEV III NPRM to use E10 as the official fuel for all required certification testing. Many studies are being done investigating the impact of the 20% ethanol fuel blend on the different components in the vehicle especially on the evaporative systems. This study focuses on the effect of ethanol content on tailpipe emissions including carbonyls. The effect of ethanol addition to gasoline fuels on regulated tailpipe emissions is investigated under different ethanol content and different ambient temperatures. In addition to THC, CO, NOX, CH4 and CO2 tailpipe emissions, the analysis includes carbonyl measurement with formaldehydes, acetaldehydes, and the other 11 carbonyl species. Testing was conducted on a 3.3 L Chrysler Town & Country vehicle at different ambient temperatures (20°F or -7°C, 50°F or 10°C and 75°F or 24°C) with indolene certification fuels containing 0, 10%, 20% and 85% ethanol. The effect of varying the Reid vapor pressure (RVP) on tailpipe emissions with E85 fuels is also discussed.
To promote utilization of renewable fuels in transportation sector, the Thai government has actively sought to obtain higher-ratio ethanol blends in gasoline as early as 2007, at which time E85 was introduced and fuel specifications were determined. The purpose of this study is to evaluate E85 fuel performance in flexible-fuel vehicles (FFVs) with considerations for tailpipe emissions, formaldehyde, acetaldehyde emissions, evaporative emission and vehicle performance. These findings will aid future research in ethanol blends. All tests were conducted utilizing three Volvo S40 FFVs and four specific ethanol blend fuels: E10, E20, E50 and E85 (E-Fuels, collectively). Tailpipe emission tests were conducted in full compliance with Thailand Industrial Standard Institute; TIS 2160 - 2546 (Euro 3 legislation). The three FFVs employed in this study demonstrated a comparable tendency toward reduction of hydrocarbon (HC) and carbon monoxide (CO) as ethanol content increased; however, acetaldehyde concentration increased slightly in all cases, E85 exhibiting the highest acetaldehyde yield. Fuel consumption of E85 increased between 35 and 38% over that of E10. Evaporative emission test results were in full compliance with Euro 3 limit values (<2 g/test) for all E-Fuels, E85 the lowest of these due to reduced raid vapor pressure (RVP). There was not a significant difference in full-load power among E-Fuels.
Due to limited fossil fuel resources and a need to reduce anthropogenic CO2 emissions, biofuel usage is increasing in multiple markets. Ethanol produced from the fermentation of biomass has been of interest as a potential partial replacement for petroleum for some time; for spark-ignition engines, bioethanol is the alternative fuel which is currently of greatest interest. At present, the international market for ethanol fuel consists of E85 fuel (with 85 percent ethanol content), as well as lower concentrations of ethanol in petrol for use in standard vehicles (E5, E10). The impact of different petrol-ethanol blends on exhaust emissions from unmodified vehicles remains under investigation. The potential for reduced exhaust emissions, improved security of fuel supply and more sustainable fuel production makes work on the production and usage of ethanol and its blends an increasingly important research topic. This paper evaluates the possibility of using petrol-ethanol blends in a modern Euro 4 vehicle without substantial engine modification. The influence of different quantities of ethanol in petrol blends (E5, E10, E25, E50 and E85) on the emission measurement of the gaseous pollutants carbon monoxide (CO), hydrocarbons (HC), oxides of nitrogen (NOx) and carbon dioxide (CO2) for a passenger car were analysed over the New European Driving Cycle (NEDC) on a chassis dynamometer. The results obtained revealed that exhaust emissions are affected by the proportion of ethanol in the blend. Engine out emissions of HC, CO and NOx were found to vary significantly with the blend used. Fuel injection time, engine-out and exhaust temperatures and the efficiency of the aftertreatment system were all also found to vary from blend to blend. Fuel consumption increased approximately in line with blend energetic content for all blends, apart from when running on E85. The experimental work presented in this paper was performed as part of a test program evaluating biofuels' influence on light-duty petrol engines for passenger cars and light commercial vehicles.
Advances in engine technology including Gasoline Direct injection (GDi), Dual Independent Cam Phasing (DICP), advanced valvetrain and boosting have allowed the simultaneous reductions of fuel consumption and emissions with increased engine power density. The utilization of fuels containing ethanol provides additional improvements in power density and potential for lower emissions due to the high octane rating and evaporative cooling of ethanol in the fuel. In this paper results are presented from a flexible fuel engine capable of operating with blends from E0-E85. The increased geometric compression ratio, (from 9.2 to 11.85) can be reduced to a lower effective compression ratio using advanced valvetrain operating on an Early Intake Valve Closing (EIVC) or Late Intake Valve Closing (LIVC) strategy. DICP with a high authority intake phaser is used to enable compression ratio management. The advanced valvetrain also provides significantly reduced throttling losses by efficient control of intake air and residuals. Increased ethanol blends provide improvements in power density due to knock resistance. Knock resistance also provides a significant potential for reduced NOx since higher dilution without knock is enabled at moderate loads typical of normal driving. E85 also shows significant advantages for particulate emissions that enable broader authority in selection of optimal injection timings for improving efficiency. An increase in the ethanol content improves low end torque providing an addition opportunity for improved fuel economy by using down-speeding for more efficient vehicle operation
This work was concerned with evaluation of the performance and emissions of potential future biofuels during advanced spark ignition engine operation. The fuels prepared included three variants of gasoline, three gasoline-ethanol blends and a gasoline-butanol fuel altogether covering a range of oxygen mass concentrations and octane numbers to identify key influencing parameters. The combustion of the fuels was evaluated in a turbocharged multi-cylinder direct fuel injection research engine equipped with a standard three-way catalyst and an external EGR circuit that allowed use of either cooled or non-cooled EGR. The engine operating effects studied at both part and boosted high load conditions included fuel injection timing and pressure, excess air tolerance, EGR tolerance and spark retard limits. A number of blends were also mapped at suitable sites across the European drive cycle under downsized engine conditions. Relative in-vehicle fuel economies were then determined via drive cycle simulation and compared to a naturally aspirated gasoline PFI engine.
The goal of this paper is to quantitatively assess the implications of congressionally mandated biofuel targets on requirements for ethanol blending, distribution, and usage in spark ignition engines in the U.S. light-duty vehicle fleet. The "blend wall" is a term that refers to the maximum amount of ethanol that can be blended into the gasoline pool without exceeding the legal volumetric blend limit of 10%. Beyond the blend wall, the additional ethanol fuel must be used in higher blends of ethanol like E85. Once the blend wall is reached, the existing fleet of flex fuel vehicles (FFVs) will be required to use E85 for some percentage of vehicle miles traveled (VMT) in order to achieve the Renewable Fuel Standard (RFS) targets. The feasibility of this requirement will depend on several major variables including (i) the total amount of ethanol to be used; (ii) the volumetric blend limit of ethanol in gasoline; (iii) the annual sales and fleet accumulation of FFVs; (iv) the availability of retail stations offering E85; (v) a measure of the attractiveness of E85 relative to gasoline relative to the price; and (iv) whether engine technology can be deployed to take advantage of the antiknock advantages of ethanol. A fleet model has been developed by several researchers in the Sloan Automotive Laboratory at MIT that can simulate the interaction of these variables in the US light-duty vehicle (LDV) fleet. Different scenarios can be adjusted individually or as a set of coordinated policies to observe the effect on the total energy equivalent fuel demand. Results from the model show that in order to meet current biofuel targets the retail availability of E85 will need to increase drastically, and at a faster rate than the current trends indicate. The certification of E15 can delay the blend wall by a few years, but results still show likely shortfalls in reaching current biofuel targets even with aggressive deployment of FFVs.
In this study, vehicle exhaust emissions and performance were studied using various renewable components with the aim of achieving a high bio-share in gasoline and compatibility with conventional cars. Several biogasoline components were included in the fuel matrix: ethanol, ETBE, isobutanol, n-butanol and renewable hydrocarbon gasoline produced from hydrotreated oils and fats. The share of bioenergy in the test fuel blends varied from 7 to 28 E eqv%, and the oxygen content from 0 to 11 m/m%. Fossil gasoline was used as the reference fuel for emissions performance, and E85 fuel as an example of a typical market fuel for FFV cars. Experimental work was carried out at -7 °C with two conventional gasoline cars and one FFV car. The measurements included regulated and unregulated exhaust emissions. The results show the possibility of increasing the bioenergy content of gasoline to up to 30% for use with conventional gasoline-fuelled cars, which are not necessarily compatible with a fuel oxygen content higher than approximately 4 m/m%.
An unmodified, conventionally fuelled, 2009 Class D vehicle with a 2.0L turbocharged gasoline direct injection engine was operated on a range of gasoline, gasoline-ethanol and gasoline-butanol fuel blends over NEDC drive cycles and WOT power curves on a chassis dynamometer. Engine performance, engine management system parameters and vehicle out emissions were recorded to investigate the response of a current state-of-the-art technology vehicle to various alcohol fuel blends. The vehicle fired on all fuels and was capable of adapting its long term fuelling trim to cope with the increased fuel flow demand for alcohol fuels up to E85. Over the NEDC tests, the volumetric fuel consumption was very strongly related to the calorific content of the fuel. CO and NOx emissions were largely unaffected for the mid alcohol blends, but CO emissions decreased and NOx emissions increased significantly for the high alcohol fuels. THC emissions were largely unaffected. Particulate mass initially reduced as the alcohol content increased, but then increased significantly for the higher alcohols. This was likely due to the poor vaporisation during cold start. During the power curves, WOT performance increased with the oxygen content in the fuel. The performance on 95RON was slightly restricted by occasional activation of the knock controller, which retarded the mean spark timing. The alcohol fuels did not suffer from knocking events but were able to use additional fuel-sourced oxygen to increase the power output and increase the turbine enthalpy.
Due to various concerns involving conventional gasoline, there has been a growing interest in the study of alternative fuels and their use in the automotive industry. There has been particular interest in the fuel effects of varying levels of ethanol blends and other alternative fuels on vehicle emissions and fuel economy. This paper will examine and compare both exhaust emissions and fuel economy for various ethanol blended fuels, and a 16 % butanol blended fuel. The results were generated using the U.S. Federal Test Procedure. Vehicles that are certified to U.S., European, and Brazilian government standards were tested. These vehicles include a flex fuel capable (FFV) 2007 Chevrolet Zafira (E100-FFV), 2007 Chevrolet Suburban (E85-FFV), 2007 Saab 9-5 BioPower (E85-FFV), 2007 Chevrolet Suburban, 2007 Pontiac G5, and a 2006 Pontiac G6. The fuels examined were E10, E20, E85, and Bu16. Each fuel was splash blended to make up the proper finished fuel blend. Fuel economy and emissions results from these fuels were compared with those from Tier 2 Emissions Certification fuel.
The emission characteristics of regulated air pollutants and carbonyls from motorcycles using gasoline blended with 3% ethanol (E3) and gasoline (E0) were investigated in this study. Nine motorcycles were operated on a chassis dynamometer and driven according to the ECE driving cycle for air pollutant measurements. In addition, durability testing was performed on two brand-new motorcycles of the same model, using E3 in one and E0 in the other, to assess the effects of E3 usage on motorcycle emissions. The results show that average emission factors of CO and THC decreased by 20.0% and 5.27%, respectively, using E3 fuel. However, NO(x) and CO(2) emission increased by 5.22% and 2.57%. The results of paired t-tests indicate that only the reduction of CO emission is statistically significant (p-value = 0.006). The emission factors of Sigma 15 carbonyls for the nine test motorcycles were 1289 +/- 502 and 1579 +/- 368 mu g/km for E0 and E3, respectively. Carbonyl emission increased by 22.5% using E3 substituted for Ea However, the differences in Sigma 15 carbonyl emission between EO and E3 were not statistically significant (p-value = 0.137). Among the 15 analyzed carbonyls, only the emission of acetaldehyde was significantly higher (p-value = 0.014) with E3. The results of durability tests show that deterioration coefficients for E3 were 1.50, 1.45, 0.84, 0.94 and 1.06 for CO, THC, NO(x), CO(2) and carbonyls, respectively. Statistical tests exhibit that using E3 as fuel does not increase the regulated air pollutants, nor carbonyl emissions for the durability test.
The current experimental study aims to examine the effects of using oxygenates as a replacement of lead additives in gasoline on performance of a typical SI engine. The tested oxygenates are MTBE, methanol, and ethanol. These oxygenates were blended with a base unleaded fuel in three ratios (10, 15, and 20 vol.%). The engine maximum output and thermal efficiency were evaluated at a variety of engine operating conditions using an engine dynamometer set-up. The results of the oxygenated blends were compared to those of the base fuel and of a leaded fuel prepared by adding TEL to the base. When compared to the base and leaded fuels, the oxygenated blends improved the engine brake thermal efficiency. The leaded fuel performed better than the oxygenated blends in terms of the maximum output of the engine except in the case of 20 vol.% methanol and 15 vol.% ethanol blends. Overall, the methanol blends performed better than the other oxygenated blends in terms of engine output and thermal efficiency.
The NOx emission and knock characteristics of a PFI engine operating on ethanol/gasoline mixtures were assessed at 1500 and 2000 rpm with λ =1 under Wide-Open-Throttle condition. There was no significant charge cooling due to fuel evaporation. The decrease in NOx emission and exhaust temperature could be explained by the change in adiabatic flame temperature of the mixture. The fuel knock resistance improved significantly with the gasohol so that ignition could be timed at a value much closer or at MBT timing. Changing from 0% to 100% ethanol in the fuel, this combustion phasing improvement led to a 20% increase in NIMEP and 8 percentage points in fuel conversion efficiency at 1500 rpm. At 2000 rpm, where knocking was less severe, the improvement was about half (10% increase in NIMEP and 4 percentage points in fuel conversion efficiency). Because there was no significant change in the end gas temperature in these experiments, the gasohol knock resistance was attributed solely to the ignition chemistry of the ethanol.
Biodiesel and bio-ethanol are expected to be the most applied biofuels in Europe in the short- to mid-term, especially in blended form with diesel and gasoline, respectively. There is a clear need to see what impact this blending will have on emissions and fuel consumption of current vehicles. Public information on this topic is mostly based on older technology. Within the Belgian research project BIOSES, emission and fuel consumption tests were performed on recent types of vehicles running on various biodiesel–diesel blends for diesel vehicles, and bio-ethanol–gasoline blends for gasoline and flex-fuel vehicles. The vehicles were tested on a proving ground with on-board emission measurement equipment, following different test cycles, including the European test cycle (NEDC) and a real-traffic-based cycle (MOL30). The paper shows an overview and discussion of the test results.