Effect Of Ethanol Blending Research Articles

Experimental study on combustion and emission characteristics of ethanol-gasoline blends in a high compression ratio SI engine

The utilization of spark induced compression ignition (SICI) is a proven method to extend the operation load range, improve thermal efficiency as well as ensure robust control of the combustion process of homogeneous charge compression ignition (HCCI). However, negative valve overlap (NVO), intake-charge heating, and other methods of achieving SICI and the knock occurrence limit its load range and industrialization. In this paper, the effects of ethanol blending with different excess air ratios (λ) on the knock and combustion characteristics, output power, indicated thermal efficiency (ITE), and emissions were investigated in a high compression ratio (CR), single-cylinder, four-stroke SICI engine. The experimental results show that weak stratification increases the knock intensity, while strong stratification suppresses knock tendency at the stoichiometric ratio. Ethanol addition can suppress knock tendency, reduce the randomness of knock and improve the combustion stability. In comparison with pure gasoline, the IMEP and ITE of E100 increase by 6.3–15.1% and 6.8–9.1% at different λ, respectively. For conditions with low ethanol blending ratio (such as 0% or 10%) and λ with 1.0 or 1.2, knock is the limitation to further improve its thermal efficiency, while fuel economy is more affected by the overall combustion phase with an increase in ethanol blending ratio and λ. There exists a non-monotonic correlation between the NOx, THC, and CO emissions and the ethanol blending ratio due to the competing effects of oxygen-containing properties, higher latent heat of evaporation (LHE), intake-charge cooling effect, and higher combustion temperature. Ethanol blending, except for E100, does not exhibit the PN reduction tendency. Knock deteriorates PN emissions, especially in nucleation mode, and ethanol blending shifts its size distribution towards nucleation mode.

Quantification of gasoline-ethanol blend emissions effects

ABSTRACT Emissions levels from current gasoline spark-ignited engines are low, and emissions changes associated with the blending of ethanol into gasoline are small and difficult to quantify. Addition of ethanol, with a high blending octane number, allows a reduction in aromatics in market gasoline. Blending behavior of ethanol is nonlinear, altering the distillation curve, including the 50% temperature point, T50. Increase in gasoline direct injection (GDI) engine technology in the fleet challenges ability of older models based on port fuel injection (PFI) results to predict the overall air quality impact of ethanol blending. Five different models derived from data collected through U.S. Environmental Protection Agency Energy Policy Act (EPAct) programs were used to predict LA92 Phase 1 particulate matter (PM) emissions for summer regular (SR) E0 (gasoline with 0% ethanol by volume), E10 (gasoline with 10% ethanol) and E15 (gasoline with 15% ethanol). Substantial reductions of PM for E10 and E15 relative to E0 were predicted when aromatics were displaced by ethanol to maintain octane rating. SR E0 and E10 were also matched to linear combinations of EPAct fuels and results showed a 35% PM reduction for SR E10 relative to SR E0. For GDI vehicles the Coordinating Research Council (CRC) E-94-3 study found that E10 had 23% or 29% PM increase. However, CRC E-129 found an E10 PM reduction of 10% when one E0 fuel and its splash blended (SB) E10 were compared. Both CRC project E-129 SB data and fuel triplets selected from the EPAct study showed variation for E15 emissions, although E-129 suggests that E15 in GDI offers about a 25% reduction of PM with respect to E0. Overall, data suggest that ethanol blending offers a modest to a substantial reduction of cold-start PM mass if aromatic levels of the finished products are reduced in response to ethanol addition. Implications: Studies of exhaust emissions effects of ethanol blending with gasoline vary in conclusions. Blending properties are nonlinear. Modeling of real-world emissions effects must consider all fuel composition adjustments and property changes associated with ethanol addition. Aromatics are reduced in E10 or E15, compared with E0, and distillation changes. PFI-derived models show reductions in cold-start PM for expected average E10 versus E0 pump fuel, due to reduced aromatic content. Relative emissions effects from older technology (PFI) engines do not predict newer engine (GDI) results reliably, but recent GDI data show reduced cold-start PM when ethanol displaces aromatics.

Effects of Ethanol Blending on the Formation of Soot in n-Heptane/Air Coflow Diffusion Flame

Laminar diffusion flame was used to study the effect of ethanol on n-heptane flame in terms of the morphology and microstructure of soot under atomization combustion. For the same carbon mass flux at the outlet of the burner, the ratio of ethanol doping in n-heptane was changed, and the soot was collected from the axial positions of the flame at different heights using the thermophoresis probe method. The results showed that the flame height increased significantly with the increasing ratio of ethanol doping. When the ratio of ethanol and n-heptane (CE/CN) was 1.5, the flame height increased by 10 mm compared with that of pure n-heptane flame. Besides, the temperature in the center of the flame decreased with the increasing ratio of ethanol doping, but the temperature in the low position was higher than that in the pure n-heptane flame, and the temperature in the high position was lower than that in the pure n-heptane flame. However, the flame temperature was the highest when the proportion of ethanol in the mixture was greater than that of n-heptane. The temperature at the flame center decreased with the increasing ratio of ethanol doping, while the temperature at the flame edge increased with the ratio. The primary particle size of soot (soot size hereafter) in all working conditions increased with the increase of flame height, which was in line with the general growth law of soot. Moreover, the soot size at the same height decreased with the increasing ratio of ethanol doping, and this trend was most obvious at the flame height of 20 mm and 30 mm. Compared with pure n-heptane, when CE/CN was 1.5, the soot size at 20 mm and 30 mm decreased by an average of 34.83%, indicating that ethanol could inhibit the surface growth of soot particle. Furthermore, the density of soot particles collected by a single copper net decreased significantly, indicating that ethanol could reduce the production amount of soot.

Investigations on effects of ethanol blending on performance and combustion characteristics of gasoline fuelled lean burn SI engine

This study discusses the effects of addition of small amount of ethanol on performance and emission behaviour of a gasoline fuelled lean burn SI engine. Experiments were carried out in a single cylinder diesel engine which is made to operate as SI engine on lean condition with gasoline as a fuel. The engine was operated at wide open throttle at a compression ratio of 10.5:1 and 1500 rpm at diverse equivalent ratios by injecting the fuel into manifold. The test outcomes stipulated that use of ethanol-gasoline blend (10% by volume) was better compared with pure gasoline. The test results also revealed that there was an accountable increase in brake power output, brake thermal efficiency and an apparent extension in the lean limit of operation with ethanol-gasoline blend. In emission front, reduction in hydrocarbon and carbon monoxide emissions were observed. There was an increase in carbon dioxide and NO emissions due to better combustion and high in-cylinder temperature. On the whole it is concluded that small ethanol addition to gasoline improves performance and reduces emission for lean operating SI engine.

Planar liquid volume fraction and SMD distribution of Jatropha vegetable oil spray: effect of ethanol blending and GLR

This research paper presents the planar distribution of Sauter Mean Diameter (SMD) and liquid volume fraction in airblast sprays of Jatropha vegetable oil. The effect of ethanol blending at different gas to liquid mass ratios (GLRs) is presented. The planar SMD distributions are obtained using Structured Laser Illumination and Planar Imaging-Laser Sheet Drop sizing (SLIPI-LSD) and Particle/droplet Imaging Analysis (PDIA) techniques. The straight vegetable oil (SVO) spray showed poor atomization at GLR 1, which rose with increasing GLR. The blending of ethanol significantly improved the atomization of SVO even at GLR 1 condition. The liquid volume fraction distribution increased with higher GLR and with the increase in the percentage of ethanol in the blend. The impact of the increase in ethanol on drop size is small at GLR of 5. The E30 blend showed uniformly distributed liquid in the spray plane with uniform SMD distribution in the range of 50 \(\upmu \)m at GLR 5.

Influence of EGR and ethanol blending on soot formation in a DISI engine

Soot formation and in-cylinder soot oxidation in an optically accessible DISI-engine is analysed for gasoline–ethanol mixtures under part load operating conditions. A volumetric extinction measurement technique was used both for the determination of the liquid fuel distribution and quantitative soot measurements. Toliso, a mixture containing isooctane and toluene (65 vol% isooctane and 35 vol% toluene) was utilised as a surrogate gasoline fuel. The EGR (EGR-exhaust gas recirculation) rate-dependence and the effect of ethanol blending (0, 20 and 40% ethanol, E0–E40) were studied at part load operation with two different injection timings. Operating point 1 (OP1) represents an early injection with piston wetting and pool fire, operating point 2 (OP2) represents a late injection timing with reduced time for mixture formation. Soot formation is more pronounced for OP1 and for E20 and E40 as compared to E0. Here the pool fire due to the fuel-dependent liquid wall film formation plays a major role in soot formation and oxidation. Late injection timing leads to increased soot formation for E20 compared to Toliso, while E40 shows lowest soot formation. Here the fuel–wall wetting is less pronounced, but mixture inhomogeneities exist, and the soot cloud covers a larger region in the cylinder. An EGR addition leads to a higher soot formation for Toliso for both operating points. The ethanol-blends show a reduction of the soot formation with EGR, which is explained by reduced combustion temperatures and the chemically bound oxygen for E20 and E40 leading to locally leaner mixtures at constant global air–fuel ratio. The study shows optimisation potentials of injection strategies for ethanol-blended gasoline in combination with EGR in DISI-engine applications.

Effects of Ethanol Blends on Performance of Spark Ignition Engine-A Review

Bio-fuels have grabbed attention of engine researchers ever since the oil crisis and increasing cost of crude oil in the 70’s. Ethanol has been the most widely researched alcoholic fuel in IC engine. The present paper discusses the effect of ethanol-gasoline blends as a bio-fuel in the conventional spark- ignition engine. The paper reviews and brings into light the properties of ethanol, production procedure and the effect of various ethanol blends on the performance of engine. The parameters focused for this study are the engine brake torque, engine volumetric efficiency and thermal efficiency with the effect on the exhaust emissions, which is one of the present prime concerns. The merits as well as the disadvantages of using ethanol as a fuel in Spark Ignition Engines also discussed. It has been seen that with the increasing proportion of ethanol in the blend, the overall thermal efficiency, heat release rate, engine volumetric efficiency and cylinder gas pressure increases. The requirement of compression ratio for occurrence of ignition also rises with the proportion of ethanol in the blend.

Effect of ethanol blending on particulate formation from premixed combustion in spark-ignition engines

Particulate formation due to combustion of a wide range of ethanol-gasoline blends were investigated in an internal combustion engine. The engine used for this study is a single-cylinder research engine, the architecture of which is representative of a modern spark ignited direct injected (SIDI) engine. Instead of direct injection, the engine was fueled using a premixed prevaporized (PMPV) mode, which supplied the fuel to the engine in a well-mixed, gas-phase air-fuel mixture in order to isolate physical effects of the fuel. This created a completely homogenous air-fuel mixture with no pockets of significantly differing equivalence ratio, liquid fuel droplets, or wetted surfaces, ensuring that particulate formation was due to homogenous, gas-phase combustion. The engine was operated at a fixed load and phasing so that the effects of varying equivalence ratio and ethanol content could be examined. The results in this work show that the addition of ethanol results in a consistent decrease in engine-out particulate proportional to ethanol content. Moreover, the critical equivalence ratio, the equivalence ratio at which significant sooting begins, increases in a linear fashion with ethanol addition. It was also shown that the shape of the particulate size distribution (PSD) is affected by ethanol content, with increased ethanol leading to more nucleation-mode dominated distributions.

エタノール混合が DME 噴霧の着火および希薄化に及ぼす影響

エタノール混合が DME 噴霧の着火および希薄化に及ぼす影響

The effect of ethanol blending on mixture formation, combustion and soot emission studied in an optical DISI engine

Abstract In various research studies, ethanol blended fuels have shown reduced particulate matter (PM) emissions in comparison to gasoline and its surrogate fuels in direct-injection spark-ignition (DISI) engines. However, there are also studies reporting increased particulate concentration for fuels with low ethanol content. In this work the mixture formation and sooting combustion behavior of isooctane and the mixture E20 (20 vol% of ethanol in isooctane) is analyzed for catalyst heating operation. These operating conditions are critical as they strongly contribute to overall soot emissions in driving cycles. Simultaneous high speed imaging of OH ∗ –chemiluminescence and natural soot luminosity measurements are performed in combination with primary particle concentration measurements using a laser induced incandescence (LII) sensor in the engine exhaust duct. At these operating conditions E20 exhibits a higher sooting tendency as compared to isooctane. In order to identify the reason for increased soot formation, the mixture formation process is analyzed by planar laser induced fluorescence (LIF) measurements. The results show that soot was formed in fuel rich regions with incomplete evaporated fuel droplets remaining from the injection event. A different evaporation process of E20 fuel spray and mixing behavior is indicated showing a more compact rich mixture cloud with surrounding lean areas near the spark plug region. This mixture stratification is characterized by higher cyclic variations and constitutes a significant source of soot formation.

The Effect of Ethanol Blending on Combustion and Soot Formation in an Optical DISI Engine Using High-speed Imaging

Biofuel components exhibit significantly different fuel properties as compared to gasoline leading to a very complex chain of effects in engine combustion. Therefore, the effects of varying composition on mixture formation, combustion and soot formation can hardly be predicted. In this study, the influence of blending 20vol% ethanol to isooctane is investigated by simultaneous OH*-chemiluminescence and soot radiation high-speed imaging. For both fuels engine load was varied for a typical catalyst heating operating point, which is characterized by increased soot formation probability. The study reveals an unexpected behavior for E20. Both the OH*-chemiluminescence and soot luminosity intensity are higher as compared to isooctane. Furthermore, for E20 the occurrence probability of droplet combustion is increased. High engine load increases the combustion intensities and probability of soot formation for both investigated fuels.

Impact of reformulated ethanol–gasoline blends on high-emitting vehicles

In-use vehicles which are high emitters (HEVs) make a large contribution to the emissions inventory. It is not known, however, whether HEVs share common emissions characteristics, and particularly the effect of ethanol blends. We study this by first examining laboratory measurements of exhaust and evaporative emissions on ethanol blends containing 21%, 26% and 30% aromatics, and a reference fuel formulated with methyl-tertiary butyl ether (MTBE). Switching from MTBE to ethanol fuels on HEVs shows no effect on the total emissions of regulated pollutants, but 1,3-butadiene emissions would increased substantially while the emissions of total carbonyls would not be affected except in the case of acetaldehyde, which would increase with EtOH. The ozone-forming potential of exhaust and evaporative emissions would be less using the EtOH blends and specific reactivity will not be incremented. Lowering the vapour pressure of the gasoline and increasing the proportions of alkylate and isomerate in the composition produces an ethanol-blended fuel with lower environmental impact both in normal vehicles and HEVs.

Effect of early injection strategy on spray atomization and emission reduction characteristics in bioethanol blended diesel fueled engine

This study is to investigate the emission reduction characteristics of bioethanol blended diesel fuel at early injection condition including spray, atomization and evaporation characteristics. The spray atomization and evaporation characteristics were investigated using spray visualization system and KIVA-3V code, respectively. In this work, the effect of ethanol blending on the spray behavior is more evident at early injection condition. In the calculation results, the droplet size of bioethanol blended fuel was smaller than that of diesel, and bioethanol blended diesel droplets firstly evaporated by its volatility and superior atomization characteristics. In early injection condition, the bioethanol blending caused an increase in indicated mean effective pressure with an extension of the ignition delay. The cooling effect of the bioethanol fuel reduced NOx. The HC emission increased and the CO emission decreased because of the ethanol blending. The geometry mean diameter and total number density increased as a result of ethanol blending, the particle number in the nuclei mode decreased, and the particle number in the accumulation mode increased in early injection condition.

Effect of ethanol blending with biodiesel on engine performance and exhaust emissions in a CI engine

The use of biodiesel as an alternative diesel engine fuel is increasing rapidly. However, due to technical deficiencies, they are rarely used purely or with high percentages in unmodified diesel engines. Therefore, in this study, we used ethanol as an additive to research the possible use of higher percentages of biodiesel in an unmodified diesel engine. Commercial diesel fuel, 20% biodiesel and 80% diesel fuel, called here as B20, and 80% biodiesel and 20% ethanol, called here as BE20, were used in a single cylinder, four strokes direct injection diesel engine. The effect of test fuels on engine torque, power, brake specific fuel consumption, brake thermal efficiency, exhaust gas temperature, and CO, CO2, NOx and SO2 emissions was investigated. The experimental results showed that the performance of CI engine was improved with the use of the BE20 especially in comparison to B20. Besides, the exhaust emissions for BE20 were fairly reduced.

Improvement in Exhaust Emissions from a Diesel Engine Utilizing Ethanol Blended Fuel

Effects of ethanol blending on performance and emissions of a direct injection diesel engine equipped with common rail injection and cold EGR systems were investigated under various ethanol blending conditions. The results indicate that ethanol blending with high injection pressure offers smoke-free combustion under high engine loading. However, this gives an increase in combustion noise and NOx emissions. In such a condition, employing pilot injection and cold-EGR lowers the combustion noise and greatly improves the NOx-PM trade-off. Under low engine loading, usage of pilot injection with proper timing and amount improves combustion stability and lowers emissions of unburned species. The overall results indicate that maximum acceptable ethanol blending does not exceed 20%.