Ethanol Blends Research Articles

Optimization of ethanol and methanol blends for enhanced performance and reduced emissions in BS-VI compliant motorbike engines

Optimization of ethanol and methanol blends for enhanced performance and reduced emissions in BS-VI compliant motorbike engines

Impacts of low-temperature heat release on unstretched laminar burning velocity in advanced flex-fuel gasoline-ethanol engines

Improving brake thermal efficiency (BTE) of flex-fuel engines can contribute to decarbonizing conventional and hybridized vehicles running on spark-ignited (SI) engines. High compression ratio (CR) and burning velocity under exhaust gas recirculation (EGR) conditions can improve the engine BTE. Ethanol fuel, which has been attracting increasing attention recently, can improve brake thermal efficiency due to its high-octane number and fast laminar burning velocity (LBV). With higher CRs, low-temperature heat release (LTHR) occurs in the unburned mixture, which affects the compositions, oxidation, and in-cylinder temperature. Such thermodynamic changes on unstretched LBV have not been thoroughly investigated, especially in production-intent next-generation flex-fuel engines. This study aims to clarify the LTHR impacts on LBV under EGR conditions using ethanol-blended gasoline surrogate fuels. The testbed used a single-cylinder SI engine fueled by E0 (gasoline surrogate), E20 (20 % ethanol + 80 % E0 by volume), E40, E60, E85, and E100. Detailed chemical reaction calculations were conducted using the boundary conditions obtained from production-intent, strong-tumble flow, and flex-fuel engine experiments. This work predicted LTHR in an unburned mixture using a zero-dimensional detailed chemical reaction calculation. LBV is predicted by a 1D kinetic laminar flame code. As a result, LTHR proceeds before the main combustion. The results show that the temperature increase associated with LTHR increases the burning velocity, while the partial oxidants decrease the burning velocity. Moreover, this work examined higher CRs using detailed chemical reaction calculations, and the results show that fuels with higher ethanol blending ratios can increase LBV in the late combustion phase.

Numerical Investigations on Reducing Unburned Hydrocarbon and Carbon Monoxide Emissions in Reactivity-Controlled Compression Ignition Using Partial Reactivity Stratification with Alternative Fuels and Additive

<div>A numerical investigation has been performed in the current work on reactivity-controlled compression ignition (RCCI), a low-temperature combustion (LTC) strategy that is beneficial for achieving lower oxides of nitrogen (NO<sub>x</sub>) and soot emission. A light-duty diesel engine was modified to run in RCCI mode. Experimental data were acquired using diesel as HRF (high-reactivity fuel) and gasoline as LRF (low reactivity fuel) to check the accuracy and fidelity of predicted results. Blends of ethanol and gasoline with DTBP (di-tert-butyl peroxide) addition in a small fraction on an energy basis were used in numerical simulations to promote ignitability and reactivity enhancement of PFI charge. Achieving stable, smooth, and gradual combustion in RCCI is challenging at low loads, especially in light-duty engines, due to misfiring and poor combustion stability. DTBP is known for enhancing cetane number and accelerating combustion, and it is mixed in a PFI blend to avoid combustion deterioration. The factors governing reactivity stratification to achieve optimal combustion phasing were investigated in the present study. DTBP decomposition and its low-temperature oxidation chemistry were found to be responsible for affecting combustion phasing, heat release patterns, and emission trends. DTBP additive and different in-cylinder strategies were applied and studied to reduce unburned emissions. Adopting a multiple injection approach utilizing dual-pulse assisted in reducing HC and CO levels. It enhances combustion quality by providing adequate control over combustion phasing. Altering operating parameters like intake temperatures reduced HC, CO, and soot emissions by 97.6%, 57.6%, and 52.8%, respectively, compared to baseline gasoline/diesel RCCI data. Optimizing the injection timings of the first and second pulse helps achieve optimal combustion phasing and a 72.95% reduction in NO<sub>x</sub> emissions. The higher injection pressure of DI helped lower the CO and soot emissions by 53.33% and 51.84%, respectively.</div>

Performance of anhydrous ethanol and gasoline blends on a SI engine: Decoupling evaporation enthalpy and knock resistance

Blending bioethanol with gasoline is recognized as a rapid solution for mitigating nonrenewable carbon dioxide emissions. This approach proves particularly meaningful in markets where the production of this biofuel aligns with sustainable practices. Understanding the alterations in the combustion process holds significance within these markets, contributing to informed decision-making and fostering environmentally conscious practices. In this context, it is widely known that highly ethanol blended fuels can provide benefits regarding suppression of knocking combustion in spark ignited engines if the quality of the base-fuel is not deteriorated to maintain octane ratings. However, the results of engine knocking investigations can be affected by two effects simultaneously. Firstly, ethanol has a beneficial effect on knock suppression due to its high enthalpy of evaporation compared to gasoline, which results in inner mixture cooling especially with direct injection. Secondly, ethanol can have beneficial effects on knock suppression by its decreased self-ignition tendency. This paper provides the set-up and results of an adapted engine testing procedure to diminish the effects of evaporation enthalpy during the knocking investigations of different highly ethanol blended fuels. The presented testing procedure at a single-cylinder research engine includes three technical steps: (1) the engine is equipped with a port fuel injection in stoichiometric operation for all tested fuels; (2) the engine is operated with constant speed of 1500 rpm and constant spark timing of 33° firing top dead center; (3) the engine is operated with fuel individual settings for the intake manifold gas pressure and intake manifold gas temperature. These parameters are adjusted to test all fuels with similar in-cylinder conditions at spark timing. The differing heating values of the fuels obviously result in differing engine loads. However, the presented testing procedure is aimed to achieve comparable in-cylinder conditions at spark timing without the effect of evaporation enthalpy. The novelty of the study lies in its adapted engine testing procedure that mitigates the cross-effects of fuel properties and operational conditions to isolate the true influences on knock occurrence. The paper provides a comprehensive description of the theoretical backgrounds, experimental set-up and post-processing procedures and also shows the results of the first measurement campaign.

Life Cycle Assessment of Bioethanol Produced from Banana Peduncle

Abstract Biofuel production has been promoted in part to reduce dependency on fossil fuels in transportation due to fewer environmental emissions. Feedstocks for biofuels include agricultural waste and non-edible crops, suggesting that large amounts of waste can be used to produce biofuels such as bioethanol, which is currently being blended with gasoline in the Philippines as transportation fuel. However, shifting from non-renewable fuels to bioethanol and other biofuels as the dominant transportation fuel must consider aspects other than fuel usage. The objectives of this study are to perform cradle-to-grave life cycle analysis on bioethanol produced from banana peduncle and determine the contributions of each stage in the life cycle to different environmental impacts and compare the results with those of other transport fuels. The contributions of each stage in the life cycle of bioethanol are modelled in openLCA software with the ReCiPe impact assessment method. It was identified that electricity use in simultaneous saccharification and fermentation, and sulfuric acid consumption are the main contributors to the different environmental impacts. Comparison of the results of banana peduncle bioethanol production stage to those of the first-generation bioethanol production showed that most of the emissions were lower except for those pertaining to freshwater ecotoxicity, human toxicity, marine ecotoxicity, and metal depletion. Comparing fuel use, environmental impacts of conventional gasoline were slightly lower than those of a 10% mix with bioethanol. But impacts of the 85% mix with bioethanol in climate change and marine eutrophication are higher by 29% and 37%, respectively, than those of conventional gasoline. Overall, increasing the ethanol concentration would reduce the emissions during fuel usage but impacts of production will increase. Potential process improvements for environmental performance of bioethanol from banana peduncle are in the pre-treatment methods and fermentation set-up in bioethanol production, use of renewable power, and ethanol blending concentrations with gasoline.

Investigating the emissions and performance of ethanol and biodiesel blends on Al2O3 thermal barrier coated piston engine using response surface methodology design - multiparametric optimization

The Response Surface Methodology (RSM) optimization technique was used to examine the effect of load, Tomato Methyl Ester (TOME), and Ethanol injection enhanced diesel on engine performance and exhaust gas emissions with a normal piston and an Al2O3 coated piston. TOME biodiesel (10, 20, and 30%) and ethanol (10, 20, and 30%) were chosen to increase BTE while minimizing BSFC, NOx, CO, smoke, and HC. The RSM technique was used to operate the engine by load (0–100%). The results revealed that engine load, TOME, and ethanol concentration all exhibited a considerable effect on the response variables. The ANOVA results for the established quadratic models specified that for each model, an ideal was discovered by optimizing an experiment's user-defined historical design. The present research efforts to improve the performance of a diesel engine by using a thermal barrier-coated piston that runs on biodiesel blends. Al2O3 is the chosen material for TBC due to its excellent thermal insulation properties. B20E30 has a 4% higher brake thermal efficiency than diesel, but B10E20 and B30E20 mixes have a 3.6% and 12% reduction in BSFC. The B20 blends lowered CO and HC emissions by 6% and 8% respectively. In terms of performance and emissions, biodiesel blends performed similarly to pure diesel, and the combination was optimized through the design of an experiment tool.

Karakteristik Pembakaran Droplet Campuran Metil Oleat – Etanol dengan Penambahan Multi -Walled Carbon Nanotubes

This research intended to investigate the combustion characteristics of methyl oleic – ethanol blend with OH functionalized multi-walled carbon nanotubes (MWCNT-OH) addition. Methyl oleic is an unsaturated fatty acid methyl ester, which is a constituent of various biodiesels. The observed fuel was a mixture of Methyl oleic with 20% vol of ethanol. MWCNT-OH content was varied by 100 ppm, 200 ppm, 300 ppm, 400 ppm, and 500 ppm (wt based). The presence of ethanol in the droplets is intended to promote the microexplosion phenomenon, generating smaller droplets and a shorter burning time. The experimental results show that the MWCNT-OH addition on the droplet of Methyl oleic – ethanol blend decreased the ignition delay and droplet burning time, while the constant burning rate and droplet temperature (and flame temperature) were increased. Reducing ignition delay time due to the higher thermal conductivity of nanofluid droplets results in more effective heat absorption from the environment and better heat transport inside the droplet. Hence, droplet vaporization, flammable mixture formation and ignition occur in a shorter time. Furthermore, this condition encourages a higher burning rate and a lower droplet burning time. The higher droplet and flame temperatures are related to the higher heating value of the methyl oleic – ethanol – MWCNT-OH mixture and higher droplet burning rate, which results in a higher heat release rate.

An experimental investigation of the impacts of titanium dioxide (TiO2) and ethanol on performance and emission characteristics on diesel engines run with castor Biodiesel ethanol blended fuel

Investigating the impact of ethanol and TiO2 on the performance and emission characteristics of diesel engines running on a blend of ethanol and castor biodiesel is the primary goal of this study. The nanoparticles of ethanol, biodiesel, and TiO2 diesel fuel were combined at several concentrations. Diesel, B10, B20, B30, B10E10T, B20E10T, B30E10T, B10E20T, B20E20T, and B30E20T were among the various fuels that were investigated. The physiochemical properties of all the sample fuels were assessed, including density, pour point, cloud point, fire point, flash point, and kinematic viscosity. Following this, other engine performance indicators, such as torque, power, and fuel-consumption, were examined. Studies were also carried out on the properties of emissions, including CO, CO2, HC, and NO. Peak braking power and engine torque were found for each fuel under investigation at around 2750 and 2500 rpm, respectively. The addition reduced the brake-specific fuel consumption for B10E20T by 7.41 % while increasing the braking engine's torque and power by 8.64 and 3.86 %, respectively, in compared to blends without the TiO2 additions. When compared to diesel, the exhaust emission data without the addition of TiO2 revealed a decrease in CO and HC emissions but an increase in CO2 and NO emissions. On the other hand, using ethanol blend reduced NO emissions. According to the overall findings, diesel engine performance, combustion characteristics, and exhaust gas emissions were enhanced averagely by 7.43 % when a certain ratio of ethanol, biodiesel, and TiO2 additives (B10E20 + 50 ppm) was used.

Experimental investigation of performance, emission, and combustion characteristics of a diesel engine using blends of waste cooking oil-ethanol biodiesel with MWCNT nanoparticles

In this study, blends of 5 % and 10 % ethanol with waste cooking oil biodiesel are mixed with Multi-Walled Carbon Nanotubes (MWCNT) at a concentration of 30 ppm. MWCNTs, known for their high surface area and unique properties, are added to potentially enhance combustion efficiency and reduce emissions. These blends are then tested in a diesel engine to evaluate their performance, emission and combustion characteristics using Design of experiment technique. After conducting various experiments and analyses, the blend of 20 % biodiesel, 10 % ethanol, and 30 ppm MWCNT was identified as the most optimal due to its favorable engine characteristics. Brake Thermal Efficiency (BTE) was increased from 3.1 % to 3.4 % with the addition of MWCNTs, indicating enhanced fuel efficiency. Moreover, average Fuel Consumption is decreased from 2.2 % to 2.5 %, suggesting improved fuel utilization. Using MWCNT 30 ppm in B20 ethanol blends (MWCNT 30 ppm B20+E10) resulted in 35 % reduction in nitrogen oxide (NOx) emissions, 37 % reduction in CO emissions and 39 % reduction in HC emissions. Hence MWCNTs demonstrated effectiveness in mitigating harmful exhaust emissions The optimized values for all parameters fall within acceptable ranges, indicated successful optimization using Response surface methodology. Additionally, statistical analysis reveals that the machine learning- XGBoost model outperformed all other advanced machine learning models across all tested metrics, including MSE, MAE, and R-square.

Optical study on the spray and combustion characteristics of diesel-biodiesel-alcohol blend fuels on a constant volume combustion chamber

The rapid increase in automobile ownership has brought about an increase in pollutant emissions, the blending of alcohols can effectively reduce conventional pollutant emissions from diesel engines. However, alcohols have poor inter-solubility with diesel fuel. This study investigates the effects of blending different alcohols on the spray and combustion characteristics of diesel, with biodiesel as the cosolvent. The results show that among the three alcohols, blending methanol has the best improvement in the gas-liquid phase spray characteristics, followed by ethanol and propanol. The GL-SCA and GL-SPA of the methanol blends are 8.2 % and 2.3 % larger than those of the ethanol blends, and 19 % and 11.9 % larger than those of the propanol blends, respectively. Among the four fuels, fuel blended with methanol emits the least normalized sum KL, 45 % less than that of diesel, 23.8 % less than that of ethanol blended fuel, and 35.3 % less than that of propanol blended fuel.

Educating Engineers on the Use of Renewable Ethanol Fuel as a Drop-in Replacement for Gasoline in Small Engines

The use of high-blend ethanol fuels to reduce emissions produced by on-road vehicles has been extensively studied. However, much less research has been done to study the effect of operating small off-road engines on high-blend ethanol fuel as a drop-in replacement for gasoline. Most small engine manufacturers only certify proper operation on low ethanol blends such as E10 (10% ethanol, 90% gasoline by volume). Most engineering students are unaware of the benefits that can be achieved when using high-blend ethanol fuel in small engines without substantial modifications. In this study, students conducted performance testing and analysis of a small engine using a dynamometer and a raw exhaust emissions analyser. The exhaust emissions and performance of the engine were evaluated using the U. S. Environmental Protection Agency (EPA) 6-mode duty cycle for small recreational engines (under 19 kW). Testing and analysis followed the recommendations of the SAE J1088 recommended practice. Students were motivated by the contemporary nature of the project and the use of commercially available equipment for testing. Further, students learned about the use of standardized testing to demonstrate the performance and emissions results.

Environmental impact and energy balance assessment in ethanol production from sugarcane molasses: A life cycle analysis in southern India

Blending ethanol with fossil fuels is regarded as an important measure to reduce overall greenhouse gas emissions and the carbon footprint. However, there is a lack of comprehensive studies addressing overall greenhouse gas emissions and energy utilization during ethanol production from sugarcane in South India. This study represents a pioneering attempt to determine the emissions and resource utilization, enabling a comparison of the carbon footprint of the ethanol production process with that of using fossil fuels. The study employed the Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET) model to calculate greenhouse gas emissions and resource utilization. Data was obtained from field studies conducted at Gayatri Sugars Limited, Telangana state, India. The collected data was input into a life cycle analysis (LCA) model in which two cane trash treatment methods were evaluated: burning and mulching. In terms of emissions, the CO2 emissions for one ton of sugarcane were 43.86 kg during cultivation, 45.98 kg during transportation, 69.05 kg during burning of cane trash, and 6.37 kg during the production of one ton of ethanol. The overall energy yield ratio was found to be 15.795 MJ/MJf. Emissions from sugarcane farming and transportation stages were high, significantly contributing to a high carbon footprint. The net emission was significantly lower for the mulching process, which also improved soil characteristics and fertility. The outcomes provide valuable insights for academia, industrial decision-makers, and policymakers at both state and central government levels.

Performance and environmental impact of ethanol-kerosene blends as sustainable aviation fuels in micro turbo-engines

The research experimentally examines the viability of ethanol (E) as a sustainable aviation fuel (SAF) when mixed with kerosene (Ke) – Jet A aviation fuel + 5% Aeroshell oil. Various blends of ethanol and kerosene (10%, 20%, and 30% vol. of ethanol added in kerosene) were subjected to testing in an aviation micro turbo-engine under different operational states: idle, cruise, and maximum power. During the tests, monitoring of engine parameters such as burning temperature, fuel consumption, and thrust force was conducted. The study also encompassed the calculation of crucial performance indicators like burning efficiency, thermal efficiency, and specific consumption for all fuel blends under maximum power conditions. Physical-chemical properties of the blends, encompassing density, viscosity, flash point, and calorific power, were determined. Furthermore, elemental analysis and FTIR were used for chemical composition determination. The research delved into analyzing the air requirements for stoichiometric combustion and computed resulting emissions of CO2 and H2O. Experimental assessments were performed on the Jet Cat P80® micro-turbo engine, covering aspects such as starting procedures, acceleration, deceleration, and emissions of pollutants (CO and SO2) during diverse engine operational phases. The outcomes reveal that the examined fuel blends exhibited stable engine performance across all tested conditions. This indicates that these blends hold promise as sustainable aviation fuels for micro turbo-engines, presenting benefits in terms of diminished pollution and a more ecologically sound raw material base for fuel production.

Global Biofuel Alliance and Roadmap for Ethanol Blending Program in India: Analysis and Perspective

Global Biofuel Alliance and Roadmap for Ethanol Blending Program in India: Analysis and Perspective

Optimization of intelligent charge compression ignition engine in hybrid electric powertrain by adaptive equivalent consumption management strategy

Dual fuel intelligent charge compression ignition (ICCI), taking advantage of two direct injection fuel supply systems, substituted low-carbon fuels for conventional fuels, improving fuel economy and emissions. This study focused on the application of the ICCI engine on the power-split hybrid powertrain and carried out the influence of the real-time energy management strategy on ICCI engine performance. Taking the ideal solution calculated by dynamic programming (DP) as the benchmark, equivalent fuel consumption minimum strategy (ECMS) and adaptive equivalent fuel consumption minimum strategy (AECMS) were compared in aspects of ICCI engine performance and state of charge (SOC) control robustness. The results showed that AECMS had better performance on SOC control, where the maximum deviation from the ideal control by DP was lower than 0.5 % during the charge sustaining stage, and the maximum deviation during the charging and discharging stages was no more than 1.5 %. In terms of engine performance control, the accumulative fuel consumption increased by no more than 20 %, and the average E85 (85 % ethanol in ethanol-gasoline blend) substitution ratio reduced by less than 8 %. Despite consuming a high proportion of E85, the accumulative fuel mass consumption of the hybrid powertrain was still 4 % lower than the conventional diesel vehicle.

A comprehensive analysis of energy, exergy, performance, and emissions of a spark-ignition engine running on blends of gasoline, ethanol, and isoamyl alcohol

This present study showed a comprehensive analysis of energy, exergy, performance, and emission characteristics of a spark-ignition engine powered by blends of gasoline-isoamyl alcohol-ethanol at volume proportions (100_0_0)% (P0E0), (90_5_5)% (P5E5), (80_5_15)% (P5E15), and (70_5_25)% (P5E25) at various engine speeds and compression ratios (CR). The outcomes of thermodynamic analyses revealed that the highest exergy and energy efficiency were 28.92 % (P0E0, 2600 rpm, CR of 9:1) and 31.01 % (P0E0, 2600 rpm, CR of 9:1), respectively. In addition, the average brake power and brake thermal efficiency for P0E0, P5E5, P5E15, and P5E25 increased by (30.36 %, 27 %, 26.74 %, 27.84 %) and (0.34 %, 0.07 %, 0.35 %, 0.33 %) respectively, while brake specific fuel consumption decreased by (2.5 %, 0.64 %, 3.62 %, 6.33 %) in the engine speed range of 2600–3200 rpm. Compared to gasoline, the maximum reduction of carbon monoxide emissions was 6.13 %, 8.81 %, and 9.96 %, while unburnt hydrocarbon emissions exhibited the maximum decrement by 5.8 %, 10.75 %, 12.58 % for P5E5, P5E15, and P5E25, respectively. However, nitrogen oxide (NOx) emissions for P5E25 tended to increase significantly compared to P0E0, while the difference in NOx emissions for P5E15 and P0E0 was marginal. Overall, P5E15 could be considered as the potential alternative fuel for spark-ignition engines towards the goal of sustainable energy conversion.

Response Surface Optimization of Brake Thermal Efficiency and Specific Fuel Consumption of Spark-Ignition Engine Fueled with Gasoline–Pyrooil and Gasoline–Pyrooil–Ethanol Blends

<div>The present study explores the performance of high-density polyethylene (HDPE) pyrooil and ethanol blends with gasoline in SI engine using statistical modeling and analysis using response surface methodology (RSM) and the Anderson–Darling (AD) residual test. The pyrooil was extracted from HDPE through pyrolysis at 450°C and then distilled to separate the liquid fraction. Two blends were prepared by combining pyrooil and gasoline, and pyrooil–ethanol mixture (volume ratio of 9:1) and gasoline, both at volumetric concentrations ranging from 2% to 8% to evaluate brake thermal efficiency (BTE) and specific fuel consumption (SFC) in a SI engine. An experimental matrix containing speed, torque, and blend ratio as independent variables for both blends were designed, analyzed, and optimized using the RSM. The results show that a 4% blend of pyrooil with gasoline (P4) and a 6% blend of pyrooil–ethanol mixture with gasoline (P6E) were optimum for an SI engine. Also, the experimental findings show that the P6E blend exhibits 11% higher BTE and 11.82% lower SFC compared to base fuel (pure gasoline), and 7.55% higher BTE and 6% lower SFC than P4. From the AD test, the residuals for BTE and SFC follow a normal distribution. The results conclude that distilled HDPE pyrooil could be used in SI engines at concentrations of P4 and P6E without requiring engine modification.</div>

Biodiesel production from eggshells derived bio-nano CaO catalyst–Microemulsion fuel blends for up-gradation of biodiesel

The utilization of bio-oil derived from biomass presents a promising alternative to fossil fuels, though it faces challenges when directly applied in diesel engines. Microemulsification has emerged as a viable strategy to enhance bio-oil properties, facilitating its use in hybrid fuels. This study explores the microemulsification of Jatropha bio-oil with ethanol, aided by a surfactant, to formulate a hybrid liquid fuel. Additionally, a bio-nano CaO heterogeneous catalyst synthesized from eggshells is employed to catalyse the production of Jatropha biodiesel from the microemulsified fuel using microwave irradiation. The catalyst is characterized through UV–Vis, XRD, and SEM analysis. The investigation reveals a significant reduction in CO, CO2, and NOX emissions with the utilization of microemulsion-based biodiesel blends. Various blends of conventional diesel, Jatropha biodiesel, and ethanol are prepared with different ethanol concentrations (5, 10, and 20 wt%). Engine performance parameters, including fuel consumption, NOX emission, and brake specific fuel consumption, are analyzed. Results indicate that the conventional diesel/Jatropha biodiesel/ethanol (10 wt%) blend exhibits superior performance compared to conventional diesel, Jatropha biodiesel, and other blends.The fuel consumption of the conventional diesel/Jatropha biodiesel/ethanol (10 wt%) blend is measured at 554.6 g/h, surpassing that of conventional diesel and other biodiesel blends. The presence of water (0.14 %) in the blend reduces the heating value, consequently increasing the energy requirement. CO and CO2 emissions for the conventional diesel/Jatropha biodiesel/ethanol (10 wt%) blend are notably lower compared to conventional C-18 hydrocarbons and various biodiesel blends. These findings accentuate the efficacy of the microemulsion process in enhancing fuel characteristics and reducing emissions. Further investigations could explore optimizing the emulsifying agents and their impact on engine performance and emission characteristics, contributing to the advancement of sustainable fuel technologies.

Environmental and performance impacts of 2-ethylhexyl nitrate and ethanol in diesel blends: A comprehensive study

This study investigates the performance and emissions of a compression ignition engine fueled with blends of ethanol and petroleum diesel with 2-EHN (2 ethylhexyl nitrate) as a cetane improver. Three blends, named E20 (20% ethanol with 80% diesel), E20A (20% ethanol, 0.1% 2-EHN, and 79.9% petroleum diesel), E20B (20% ethanol, 0.2% 2-EHN, and 79.8% petroleum diesel), and petroleum diesel were analyzed for their brake thermal efficiency (BTHE), specific fuel consumption, net heat release rate, indicated thermal efficiency, and emissions of carbon monoxide (CO), CO2, hydrocarbon (HC), and NOx. The experiments were conducted at variable loading conditions and at compression ratio of 16.5. Results showed that at no load conditions, petroleum diesel exhibited higher indicated power (IP) compared to E20, E20A, and E20B. However, at full load conditions, blend E20B showed higher IP compared to petroleum diesel, E20, and E20A. The blend E20B at a compression ratio of 16.5 showed the highest BTHE of 27%, compared to petroleum diesel (25%) under full load conditions, making it a better performing fuel. However, at higher loads and compression ratio of 16.5, the blends E20A and E20B exhibited emissions of CO, HC, CO2, and NOx that were significantly higher than diesel and E20 at all load conditions. Specifically, at full load conditions and compression ratio of 16.5, the emissions for each fuel were as follows: CO emission for E20, E20A, and E20B was around 0.01%, much less than petroleum diesel (0.1%); HC emission for E20 (15 ppm), E20A (17 ppm), E20B (10 ppm) was much higher than petroleum diesel (2.5 ppm); CO2 emission for E20, E20A, and E20B was about 13% less than petroleum diesel (15%); and NOx emission for E20, E20A, and E20B was around 150 ppm, comparable with petroleum diesel (140 ppm). These results imply that further improvements are required in using ethanol blended alternate fuel in diesel engines with 2-EHN (cetane improver) to reduce emissions with improved performance.

Evaluating Lean Combustion Cycle Stability and Emissions in Spark Ignition Engines with Gasoline, Ethanol, and Methanol Blends

Abstract Fuels for vehicles account for a large portion of the world’s total energy demand, which in turn leads to increased carbon emissions. Ethanol and methanol are a fuel with a simple carbon chain and OH- bonds. It has similar properties to gasoline, and ethanol can be made from the fermentation of plant carbohydrates, called bioethanol. The advantage of using bioethanol is that it contributes to carbon neutrality. This paper will investigate the use of three manually blended gasoline ethanol and methanol (GEM) fuels in a spark ignition engine to address cycle-to-cycle variation (CCV), knock potential, and emissions with lean blend conditions. In the experiments conducted, the air-fuel ratio was conditioned lean by utilizing an electronic control unit to adjust the injector spray duration. This experiment provides results that there is a potential for mild knocking on the use of alcohol fuel with lean fuel mixture conditions at engine speed 4000 RPM, while at engine speed 6000 RPM and 8000 RPM the use of GEM tends to be stable, but in the CCV results the increase in COV (coefficient of variation) value using GEM fuel tends to be more sloping, especially with the addition of more methanol. Emission results from the use of GEM produce top emission CO2 value obtained by the E5M15 mixture at λ=1.2 and an engine speed of 8000 RPM, with a value of 13.75% and then peak CO2 emissions at a value of λ = 1.2 whereas in the use of pure gasoline peak CO2 is at a value of λ = 1.1.