Ethanol-gasoline Blends Research Articles

Influence of Elevated Fuel Temperatures On the Spray Characteristics of Gasoline - Ethanol Blends

Abstract In this study, the effect of elevated fuel temperatures on the spray characteristics of gasoline-ethanol blends were studied in an optically accessible constant volume spray and combustion vessel. MAHLE SmartHeat® is a fuel heater located directly upstream of the fuel injector. High speed images of the spray injected from a six-hole gasoline direct injection injector typical of a side-injection engine were captured with shadowgraph imaging technique. Two fuel blends, gasoline with 10% ethanol (E10) and 85% ethanol (E85) were investigated at ambient conditions of 1 bar, 45°C and 4 bar, 180°C at an injection pressure of 100 bar. Fuel temperatures were varied from 75 to 250°C. A comparison of the near nozzle and the global spray characteristics was made for the two fuels in the range of fuel temperatures selected. Results showed that flash boiling leads to two primary effects for the two fuel blends: (i) an appreciable increase in spray angle near the exit of the nozzle followed by (ii) a decrease in spray angle downstream of the nozzle due to the interaction of the plumes and the collapsing of the spray. Furthermore, for both fuel blends, upon flash boiling, entrainment and mixing were reduced downstream of the nozzle because of the collapse of the spray. To reduce this effect, nozzle orientations and geometries should be modified.

Experimental investigation on operating light-duty diesel engine using ethanol–gasoline blends in a homogeneous charge compression ignition combustion mode

The advanced diesel combustion mode of homogeneous charge compression ignition (HCCI) provides simultaneous lessening of soot and oxides of nitrogen (NOx) emissions. However, HCCI operations with low volatility and high reactivity diesel fuel require energy-intensive vaporizers and suffer from a restricted operating load range. In this work, high volatility, and low reactivity ethanol–gasoline blends were utilized as fuels in a port fuel injected light-duty diesel engine operated in HCCI mode to address this limitation. To study the effect of adding ethanol to the test fuels, its content was progressively increased from 10% to 60% by simultaneously reducing the gasoline content. 6% of an ignition improver, 2-ethylhexyl nitrate (2-EHN), was added to test fuels to attain stable HCCI combustion in the test engine at lower engine loads. A combined experimental and statistical approach was followed to characterize the HCCI engine combustion, performance and emissions. The impact of independent operating factors of ethanol–gasoline fuel blend composition and engine load on the various response parameters was estimated using multi-regression models developed based on the response surface method (RSM). The optimization of engine parameters was performed using the desirability approach of RSM to maximize performance and minimize emissions. The engine operating load range was extended from 23% (1.22 bar BMEP) to 86% (4.63 bar BMEP) with ethanol–gasoline–2-EHN-fuelled HCCI, which was a substantial improvement over the achievable load range only up to 38% (2.02 bar BMEP) with diesel-fuelled HCCI. All the multi-regression models developed were statistically significant at a 95% confidence level. The results showed that the indicated thermal efficiency improved, and soot and NOx emissions reduced with increased ethanol content in the test fuels. The test engine showed optimal working conditions when operated using 49% ethanol in the test fuels at 75% engine load. To benchmark the HCCI engine performance under optimal operating conditions, it was compared with conventional diesel combustion at 75% engine load. The NOx and soot emissions decreased by 76% and 98%, respectively, while indicated thermal efficiency increased by 20% for HCCI than conventional mode. The optimal fuel reactivity was determined at various engine loads by using the model equation developed for combustion phasing. According to the findings of this study, the fuel management strategy of using ethanol and gasoline blends is a viable method to enhance the performance and emission metrics of HCCI engines.

Numerical investigations on the performance and emissions of a turbocharged engine using an ethanol-gasoline blend

Due to a scarcity of fossil fuel supplies and concerns about pollution, the use of ethanol in gasoline has become a priority in the automobile industry. This paper aims to investigate the effect of different ethanol-gasoline fuel blend ratios, namely E20 (% ethanol + % gasoline), E50 (% ethanol + % gasoline), and E75 (75% ethanol + 25% gasoline) on a 1.6 L turbocharged, 4-cylinder, 2017 Proton Preve Premium CFE CVT engine, where E0 (pure gasoline) is taken as reference fuel. In addition, different speed intervals, which include 1000 RPM, 2000 RPM, and 5000 RPM, are employed for each fuel blend. The production of four major emissions, NOx, CO, CO2, and HC, and performance parameters such as thermal efficiency, volumetric efficiency, and brake-specific fuel consumption, are evaluated using SolidWorks for CAD modelling. This then is transferred to ANSYS for emission and performance analysis. According to the findings, increasing ethanol concentration and engine speed increases volumetric efficiency and brake-specific fuel consumption by up to 12.89% and 6.59%, respectively. It was also discovered that ethanol and increasing engine speed had an 11.39% reduction in thermal efficiency. Furthermore, the addition of ethanol occurs, along with an increase in speed, exhaust gas emissions are reduced by up to 21.74% compared to pure gasoline.

Ethanol blending effects on auto-ignition and reaction wave propagation under engine-relevant conditions

Ethanol as an attractive oxygenated fuel is often blended with gasoline to yield beneficial anti-knocking performance. Due to the distinctions in fuel chemistry, the combustion behavior of gasoline-ethanol blends is not fully understood. This study investigated ethanol blending effects on auto-ignition and reaction wave propagation under engine-relevant conditions covering the negative temperature coefficient (NTC) region. Three ethanol blending levels (i.e., E10, E20, and E30 on a volume basis) were introduced into gasoline surrogates. Characteristic timescale analysis for homogeneous auto-ignition was conducted, and localized hotspot auto-ignition and reaction wave propagation was investigated for different gasoline-ethanol blends. Meanwhile, ethanol blending effects on detonation development were comparatively explored. The results show that ethanol addition significantly suppresses fuel reactivity for homogeneous scenarios, especially in low-temperature regions, manifesting prolonged timescales and diminishing NTC behavior. Despite this, different reaction wave propagation modes can be identified during transient auto-ignition and reaction wave propagation, including deflagration, detonation development, and thermal explosion. The detonation wave is always at an underdeveloped status under engine-relevant conditions, and the induced pressure characteristics are sensitive to initial temperatures, hotspot sizes, and fuel reactivity. Meanwhile, ethanol addition tends to promote transient detonation development by elevating the reaction front propagation speed inside the hotspot and enhancing the deflagration to detonation transition outside the hotspot. Such observations are not contrary to that ethanol yields beneficial anti-knocking performance because only chemical effects of ethanol blending are addressed, without considering vaporization cooling effects. The present work demonstrates that ethanol addition globally suppresses engine knocking, but it may induce stronger knocking intensity once end-gas auto-ignition and detonation development are initiated. The current study provides useful insights into ethanol perturbative effects on auto-ignition and reaction wave propagation from chemical perspectives.

Induction of a Consumption Pattern for Ethanol and Gasoline in Brazil

Historically, carbon dioxide emissions from transport have been a globally discussed and analyzed problem. The adoption of flex fuel vehicles designed to run ethanol–gasoline blends is important to mitigate these emissions. The main purpose of this paper is to analyze the impact of the ethanol–gasoline price ratio on different vehicle models, and discuss the opportunities to increase ethanol consumption from this perspective. Our analysis shows that the use of a unique fuel economy ratio for all flex–fuel vehicles in the country significantly reduces the opportunity of some customers to purchase hydrous ethanol. The paper also discusses possible actions to provide adequate information that may increase the possibility of fuelling vehicles with a high-level ethanol blend.

Effects of direct injection and mixture enleament on the combustion of hydrous ethanol and an ethanol-gasoline blend in an optical engine

Ethanol is a renewable fuel and can be used in electric hybrid vehicles concepts, especially for countries capable of producing such fuel in a sustainable way. A strategy to enhance these concepts is the use of lean-burn combustion, which is an effective way to improve the fuel economy from spark-ignition engines, while obtaining low pollutant emissions. However, these improvements are complicated to achieve in a practical way because lean combustion has low rates of reaction, extinction, and misfire cycles, leading to cyclical variability for the engine operation. The drawback becomes even greater when lean combustion is associated with commercial ethanol fuels and direct injection. Therefore, the objective of the present work is to provide an experimental analysis of spray guided direct injection with commercial fuels used in a consolidated market for the use of ethanol such as the Brazilian one, in particular hydrous ethanol (E95W05) and ethanol-gasoline blends (E27G73). The experiments were conducted in an optically accessible spark-ignition engine and the lean combustion effects on engine cycle variability, performance, flame morphology, and exhaust emissions were assessed. In general, the results indicated that combustion instabilities can be correlated from thermodynamic and optical analyses. Flame instabilities for E95W05 were associated with the lower flame propagation speed caused by the temperature reduction during lean combustion. Additionally, exhaust emissions contained the presence of unburned ethanol which increased when combustion became leaner. Moreover, the lower flame propagation speed was one of the factors responsible for reducing engine performance and increasing combustion variability. The results indicated that vaporization was a relevant phenomenon affecting ethanol combustion in the direct injection mode. The cooling effect of fuel vaporization presented itself as a powerful means for the reduction of NOx and aldehydes, even for the lean operation. Higher emissions of CO and THC were also observed for the engine operating with E95W05 when compared to E27G73. The results of the present work showed that special attention must be paid to the use of commercial fuel with a high ethanol content in spray-guided direct injection engines, especially during lean-burn combustion, in order to not compromise the performance nor increase pollutant emissions.

Evaluation of the Effects of Methanol and Ethanol Additions on Performance and Emissions in a Spark Plug Ignition Engine Fueled with Gasoline

The aim of this experimental study was to investigate the effect of addition of methanol and ethanol (5% - 10% and 15%) as a fuel at low rates to gasoline fuel against performance, and emissions characteristics. The experiments were carried out in a single cylinder, four-stroke, air-cooled spark plug ignition engine at various engine loads (2 - 2.5 - 3 - 3.5 and 4 Nm) and constant engine speed (2500 rpm). Performance, and emission characteristics of gasoline, methanol-gasoline and ethanol-gasoline blends were evaluated. When the results are examined, with the addition of ethanol and methanol, the specific fuel consumption and specific energy consumption in-creased, while the brake thermal efficiency decreased. Apart from that, CO and HC emissions have improved. The lowest CO and HC emissions were obtained in G85M15 and G85E15 fuels, respectively. Compared to gasoline, a reduction in CO and HC emissions of over 50% was observed.

An analysis of speciated hydrocarbons in hydrous ethanol (H100) and ethanol-gasoline blend (E22) for vehicle exhaust emissions

Speciation and quantification of hydrocarbons (HC) in exhaust emissions are essential when making an evaluation of MIR (maximum incremental reactivity) and OFP (ozone forming potential) factors with different fuels. In Brazil, flex-fuel vehicles were launched in 2003 and can operate with H100 (100% hydrous ethanol, 4.0–4.9% vol/vol of water), commercial gasohol (gasoline blended with 18–27% vol/vol anhydrous ethanol) or any blend of these fuels. The main difficulties when conducting an analysis of HC with these fuels, are the presence of several contaminants, the interference of ethanol and relatively high concentrations of C2 species. In this study, a new analytical method was employed that was based on a heart-cutting gas chromatography approach. Two flex fuel vehicles, using H100 and E22 (22% v/v of anhydrous ethanol), were tested with the EPA-75 drive cycle (in accordance with the requirements of ABNT/NBR 6601) and HC (C2–C12) in the three gas exhaust phases (cold start, stabilized and hot start) were analyzed. In the case of the latest vehicle (PROCONVE L6, Tier 2 equivalent), with H100, the MIR and OFP values were 5.7 ± 0.3 and 0.032 ± 0.005 gO3 km−1, respectively. When fueled with E22, the MIR and OFP values were determined as 3.6 ± 0.2 and 0.015 ± 0.001 gO3 km−1, respectively. To the best of our knowledge, this was the first complete HC (C2–C12) speciated analysis conducted in Brazil using H100 and E22 (without any significant contamination with ethanol as fuel) and aided by heart-cutting gas chromatography.

Relative particle emission tendencies of 2-methyl-3-buten-2-ol–gasoline, isobutanol–gasoline, and ethanol–gasoline blends from premixed combustion in a spark-ignition engine

Critical sooting equivalence ratios and subsequent particulate formation during spark-ignition combustion were studied for blends of ethanol, isobutanol (2-methyl-1-propanol), and methylbutenol (2-methyl-3-buten-2-ol) with gasoline using premixed prevaporized (PMPV) fueling. The air–fuel mixture was supplied to the engine in a well-mixed gaseous state allowing the chemical sooting tendency of the fuels, as measured by the critical sooting equivalence ratio, to be quantified. The engine was operated at a fixed load and phasing with varying equivalence ratio to determine the critical sooting equivalence ratio and evolution of the particle size distribution (PSD) for each fuel. Each alcohol was splash blended with a gasoline blendstock for oxygenate blending (BOB) at three different blend levels. Ethanol was blended at 10, 20, and 30% by volume (E10, E20, and E30). Isobutanol and methylbutenol blends were matched to ethanol on an oxygen weight percent basis resulting in blends of 16, 32, and 49% and 18, 37, and 56% by volume for isobutanol and methylbutenol, respectively. The results of this work show that increases in alcohol content consistently decreased the chemical sooting tendency and particulate emissions for all alcohol–gasoline blends tested. The level of decrease in particulate on a volume basis can be ordered isobutanol < methylbutenol < ethanol. On an oxygen weight percent basis, the order is ethanol < isobutanol < methylbutenol. The results demonstrate that methylbutenol has a lower chemical sooting tendency than isobutanol, and, given its other properties, is a potentially promising biofuel for blending with gasoline.

Effects of Nitro-Paraffin Based Fuel Additive on Performance and Emission Characteristics of Motorcycle Gasoline Engines

Studies on the effective use of available fuel resources and the emission reduction of vehicles towards clean energy are always of interest for the sustainable development goals of the world nations. For that purpose, this paper studies the effects of nitro-paraffin-based fuel additives on the performance and emission characteristics of spark-ignition engines of motorcycles running on E5 gasoline-ethanol blends. The additive substance is referred as Maz-Nitro (Maz) supplied by Maz Energy Pte Ltd., which employs a unique combination of nitro-paraffins and 1.82% of ester oil. The studies were conducted on motorcycle engines by laboratory tests on the chassis-dyno and by field tests on the road under different engine operating conditions and different additive dosages blended in fuel. The results showed that the additive with the dosage of 750 ppm gives a good improvement of engine operation in terms of fuel-saving and emission reduction. The average power improvement and fuel-saving at engine full load are 2.82% and 2.97%, respectively. The average reductions of CO, HC, and NOx emissions are 9.05%, 12.8%, and 2.03%, respectively. The use of this fuel additive may significantly contribute to reducing environmental pollution and saving fuel resources.

The Use of a Time-Frequency Transform for the Analysis of Electrochemical Noise for Corrosion Estimation

This work shows the results of evaluating the corrosion type and rate (CR) in the 6061-T6 aluminum alloy exposed to ethanol-gasoline blends (E0, E10, E20, E30, E40, E60, E80, and E100) by analyzing electrochemical noise (EN) signals using the Shannon energy (SSE) and the synchrosqueezing transform (SST). The obtained results are compared against the obtained with the statistical method (Location Index, LI). The results obtained with the SSE method showed that the corrosion type in the 6061-T6 aluminum alloy is classified better than using the statistical method. Moreover, the SST results showed that the corrosion rate increased with the increment of the ethanol content in the ethanol-gasoline blends from values in the order of10−4to10−3mm/year.

Experimental and Simulation Analysis on Spray Characteristics of Hydrous Ethanol–Gasoline Blends

Abstract Hydrous ethanol application in engines can not only improve combustion and reduce emissions but also save energy consumption in the production process, which is a potential alternative fuel for engines. However, little research has been conducted on the influences of hydrous ethanol, gasoline, and hydrous ethanol–gasoline blends on spray characteristics, especially the phenomenon of flash boiling. In this investigation, the spray characteristics of hydrous ethanol and gasoline have been conducted using a constant volume chamber system, and the spray characteristics of hydrous ethanol–gasoline blends have been simulated using validated models. The results show that hydrous ethanol fuel is more likely to enter a flash-boiling state in comparison with gasoline. In addition, the spray penetration of hydrous ethanol is higher than that of gasoline, which increases by 10% approximately under the same temperature. Moreover, the spray cone angle of test fuels is between 32 deg and 43 deg and decreases with the increase of back pressure in trend. Besides, the spray projection area of hydrous ethanol and gasoline decreases significantly with the increase of back pressure. In terms of simulation, the spray penetration of E10w, E20w, E50w, and E85w fuels decreases with the increase of back pressure.

Experimental study on the effects of ethanol blends on the combustion process, power performance and emission reduction of a motorcycle spark-ignition engine

This work investigates the effects of ethanol-blended gasoline fuels on a motorcycle engine's power performance and emission reduction compared with conventional gasoline fuel. Experiments were conducted on different ethanol-blended fuels E0, E30, E50, E85, and E100 for a spark-ignition motorcycle engine at various engine speeds and loads. The brake power increased with the ethanol blending ratio; E100 fuel produced the highest brake power, and E0 fuel made the lowest. The rise of ethanol in blends contributed to the retarding of ignition and reducing the peak combustion pressure and maximum heat release. The CO emission for E100 and its blends was less than gasoline fuel. The HC emissions decreased with the increase in ethanol blending ratio, and the difference was more considerable for E0 and E100 fuels at low engine speed than at higher engine speeds. Compared with E0 fuel, ethanol blends had lower NOx emissions and greater reduction levels.

Chemical kinetic investigation on NOx emission of SI engine fueled with gasoline-ethanol fuel blends

Understanding the nitrogen oxide (NOx) formation chemical kinetic mechanism and analyzing the effect of relevant influence parameters are the effective strategy for NOx emission control. Based on the essential role of ethanol-gasoline blends among oxygenate alternative fuel, the experiments in a GDI (gasoline direct injection) SI (spark ignition) engine and the chemical kinetic simulation were carried out. According to the validated model, seven NO contributing reactions and three reaction pathways were observed. Besides the thermal NO formation pathway, two other pathways with N2O and NNH through NH-HNO-NO have nonnegligible places in the high engine speed condition. As for the parameters, initial temperature aggravates NO emission, initial pressure and ethanol fraction inhibit NO, which influence it through thermal NO pathway and have slight impact on the other two pathways. While with the increase of equivalence ratio (ER) from 0.5 to 1.0, ER promotes first and then resists NO formation, getting highest emission when ER equals to 0.85. In a lean burn condition, the thermal pathway is highly inhibited and the N2O pathway is sharply accelerated. Through current work, NOx producing mechanism under high-speed condition is investigated comprehensively, which not only completes the total NO formation pathways from atmospheric N2 but also provides reference for the designing and modification of low harmful NOx emitting gasoline-ethanol engines.

Methanol/Ethanol/Butanol-Gasoline Blends Use in Transportation Engine—Part 1: Combustion, Emissions, and Performance Study

Abstract Primary alcohols such as methanol, ethanol, and butanol have exhibited excellent potential as possible alternative fuels for spark ignition (SI) engines because they are renewable, cleaner, and safer to store and transport. However, it is important to investigate the technical feasibility of adapting these primary alcohols in existing SI engines. In this research, a multi-point port fuel injection (MPFI) system equipped SI engine was used for assessing and comparing the combustion, performance, and emission characteristics of various alcohol-gasoline blends (gasohols) vis-à-vis baseline gasoline. The experiments were performed at different engine loads at rated engine speed. Experimental results exhibited relatively superior combustion characteristics of the engine fueled with gasohol than the baseline gasoline, especially at medium engine loads. Among different test fuels, the methanol-gasoline blend (GM10) exhibited relatively more stable combustion characteristics than the ethanol-gasoline blend (GE10) and butanol-gasoline blend (GB10). In this study, relatively superior engine performance of the gasohol-fueled engine was observed at all engine loads and speeds. GB10 exhibited the highest brake thermal efficiency (BTE), followed by GM10 amongst all test fuels. The effect of improved combustion was also reflected in the emission characteristics, which exhibited that GB10 emitted relatively lower carbon monoxide (CO) and hydrocarbons (HCs) than other test fuels. GB10 emitted relatively higher nitrogen oxides (NOx) than GM10 and GE10. Unregulated emission results exhibited that the engine fueled with gasohols emitted relatively lower sulfur dioxide (SO2), ammonia (NH3), and various other saturated and unsaturated HCs than the baseline gasoline. The GM10-fueled engine was relatively more effective in reducing unregulated emissions among all test fuels. This study concluded that methanol and butanol blending with gasoline resulted in superior engine performance and reduced harmful emissions in MPFI transport engines. This offered an excellent option to displace fossil fuels partially and reduce emissions simultaneously.

Numerical analysis of soot emissions from gasoline-ethanol and gasoline-butanol blends under gasoline compression ignition conditions

In the present work, computational fluid dynamics (CFD) simulations of a single-cylinder gasoline compression ignition (GCI) engine were performed to investigate the impact of blending two biofuels, ethanol and n-butanol, with gasoline on the trade-off between combustion phasing and soot emissions under low load conditions. In order to represent market gasoline (RD5-87), a four-component toluene primary reference fuel (TPRF) + ethanol (ETPRF) surrogate (with 20% ethanol by mole; E20) was formulated using a neural network based octane predictor such that the surrogate had the same ethanol content, Research Octane Number (RON) and Octane Sensitivity (S). In addition, a novel skeletal kinetic mechanism for ETPRF and TPRF + n-butanol (BTPRF) blends, incorporating polycyclic aromatic hydrocarbon (PAH) chemistry, was developed. A three-dimensional (3D) engine CFD formulation employing the skeletal mechanism, adaptive mesh refinement (AMR), finite-rate chemistry approach, and hybrid method of moments (HMOM) was adopted to capture the in-cylinder combustion phenomena and soot emissions. The engine CFD model was validated against RD5-87 experimental data for a broad range of start-of-injection (SOI) timings (-21/-27/-36/-45 crank angle degrees (CAD) after top-dead-center (aTDC)), with respect to in-cylinder pressure, heat release rate, combustion phasing, and soot emissions. The closed-cycle simulation results were analyzed to elucidate the non-monotonic trend of soot emissions versus SOI timing: SOI-36 > SOI-45 > SOI-21 > SOI-27. Thereafter, the validated CFD model was employed to simulate the combustion of a gasoline-ethanol blend with 45% (by mole) ethanol (E45) and a gasoline-butanol blend with 45% (by mole) n-butanol (B45) under the same operating conditions to study the effects of fuel composition and SOI timing on combustion phasing and soot emissions. The sooting propensity followed the trend: B45 > E20 > E45 at all SOI timings. Overall, it was observed that the autoignition propensity was primarily related to fuel chemistry. On the other hand, sooting propensity showed strong coupling with both fuel chemistry and physical properties, with greater impact of fuel physical properties at advanced SOI timings.

Impacts of applying ethanol blended gasoline and evaporation emission control to motor vehicles in a megacity in southwest China

The use of ethanol blended gasoline and evaporation emissions control are effective means to reduce air pollutant emissions from motor vehicles. However, there is currently a lack of comprehensive assessment of the impact of these measures on air quality, in particular to control volatile organic compounds (VOCs), an important precursor to PM2.5 and O3 formation. Therefore, this study sets up different motor vehicle pollution control scenarios based on ethanol gasoline substitution and evaporative emission control, respectively. The emission changes of atmospheric pollutants, O3 formation potential (OFP) and VOCs species from motor vehicles under each control scenario were analyzed, and the chemical transport model WRF/CMAQ was used to evaluate the changes of pollutant concentration in the ambient air under different scenarios. The results show that the VOCs emissions from motor vehicles in Chengdu increased by 25% from 2014 to 2019, which is attributed to the rapid growth of motor vehicle population and the aggravation of road congestion. Under different control scenarios, the emission of NOx, VOCs and PM2.5 decreased to different degrees, mainly from evaporation emissions control measures. The use of ethanol blended gasoline can reduce the VOCs emissions while increased OFP by 26%, due to the presence of highly reactive species in the VOCs source profiles, which ultimately determined the OFP of motor vehicles. Thus, it is necessary to the control of alkenes, aromatics, oxygenated VOCs (OVOCs) and other highly reactive characteristic emission species of gasoline vehicles. The simulation results of model show that under different control scenarios the PM2.5 concentrations decreased to different degrees, the urban area with the maximum decrease rate of 9.0–9.2%. The combination of the use of ethanol blended gasoline and evaporation emissions control had a good effect on PM2.5 concentration control, while the evaporation emissions control of motor vehicles alone can lead to a decrease in O3 concentration, i.e. a decrease by 1.9–2.5%.

Experimental Investigation of Hydrous Ethanol Gasoline on Engine Noise, Cyclic Variations and Combustion Characteristics

Nowadays, the noise pollution of internal combustion engines is a very important factor influencing human health and is the main noise source of urban environmental noise. Additionally, the main source of gasoline engine noise consists of combustion noise in the cylinder, where the combustion noise is influenced by the combustion processes within the combustion chamber, especially the cyclic variation in the engine combustion. Thus, the inter-relationship between engine noise, cyclic variation and combustion is of great interest to be explored. Moreover, despite the environmental advantages of clean energy, the impact of different fuels on the internal combustion engine’s noise emissions cannot be ignored. As a result, in this work, three blends were prepared and used as test fuels, namely pure gasoline (E0), 10% hydrous ethanol (E10W) and 20% hydrous ethanol (E20W) by volume, accompanied by engine operating at a steady speed of 2000 r/min under various loads. The experimental results show that lower engine noise was observed for both E10W and E20W compared to E0. Upon the addition of hydrous ethanol, the peak in-cylinder pressure increased while the maximum pressure rise rate ((dp/dφ)max) decreased at the low and medium loads. Furthermore, the coefficients of variation in indicated mean effective pressure (COVimep) and COV(dp/dφ)max for the two blended fuels were higher than those for pure gasoline. Compared with those of E20W, E10W has lower COVimep and COV(dp/dφ)max at low and medium loads. The (dp/dφ)max and noise emission have a positive relation when the engine is fueled with the hydrous ethanol–gasoline blends, whereas the cyclic variation parameters vary in the opposite direction of the noise emission level for all the blend mixtures. Moreover, (dp/dφ)max has an essential effect on the combustion noise from a gasoline engine.

Experimental comparative study on combustion, performance and emissions characteristics of ethanol-gasoline blends in a two stroke uniflow gasoline engine

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.

Comparison of the combustion characteristics of gasoline and gasoline–ethanol blend under gasoline compression ignition mode

Comparison of the combustion characteristics of gasoline and gasoline–ethanol blend under gasoline compression ignition mode