Combustion, performance and emission characteristics of a DI diesel engine fueled with ethanol-biodiesel blends

In this study, Euro V diesel fuel, biodiesel, and ethanol-biodiesel blends (BE) were tested in a 4-cylinder direct-injection diesel engine to investigate the combustion, performance and emission characteristics of the engine under five engine loads at the maximum torque engine speed of 1800 rpm. The results indicate that when compared with biodiesel, the combustion characteristics of ethanol-biodiesel blends changed; the engine performance has improved slightly with 5% ethanol in biodiesel (BE5). In comparison with Euro V diesel fuel, the biodiesel and BE blends have higher brake thermal efficiency. On the whole, compared with Euro V diesel fuel, the BE blends could lead to reduction of both NO_x and particulate emissions of the diesel engine. The effectiveness of NO_x and particulate reductions increases with increasing ethanol in the blends. With high percentage of ethanol in the BE blends, the HC, CO emissions could increase. But the use of BE5 could reduce the HC and CO emissions as well.     

Combustion performance of bio-ethanol at various blend ratios in a gasoline direct injection engine

Bio-ethanol has the potential to be used as an alternative to petroleum gasoline for the purpose of reducing the total CO₂ emissions from internal combustion engines and this paper is devoted to the investigation of using different blending-ratios of bio-ethanol/gasoline with respect to spark timing and injection strategies. The experimental work has been carried out on a direct injection spark ignition engine at a part load and speed condition. It is shown that the benefits of adding ethanol into gasoline are reduced engine-out emissions and increased efficiency, and the impact changes with the blend ratio following a certain pattern. These benefits are attributed to the fact that the addition of ethanol modifies the evaporation properties of the fuel blend which increases the vapour pressure for low blends and reduces the heavy fractions for high blends. This is furthermore coupled with the presence of oxygen within the ethanol fuel molecule and the contribution of its faster flame speed, leading to enhanced combustion initiation and stability and improved engine efficiency.     

Study of oxygenated biomass fuel blends on a diesel engine

Vegetable methyl ester was added in ethanol–diesel fuel to prevent separation of ethanol from diesel in this study. The ethanol blend proportion can be increased to 30% in volume by adding the vegetable methyl ester. Engine performance and emissions characteristics of the fuel blends were investigated on a diesel engine and compared with those of diesel fuel. Experimental results show that the torque of the engine is decreased by 6%–7% for every 10% (by volume) ethanol added to the diesel fuel without modification on the engine. Brake specific fuel consumption (BSFC) increases with the addition of oxygen from ethanol but equivalent brake specific fuel consumption (EBSFC) of oxygenated fuels is at the same level of that of diesel. Smoke and particulate matter (PM) emissions decrease significantly with the increase of oxygen content in the fuel. However, PM reduction is less significant than smoke reduction. In addition, PM components are affected by the oxygenated fuel. When blended fuels are used, nitrogen oxides (NO_x) emissions are almost the same as or slightly higher than the NO_x emissions when diesel fuel is used. Hydrocarbon (HC) is apparently decreased when the engine was fueled with ethanol–ester–diesel blends. Fuelling the engine with oxygenated diesel fuels showed increased carbon monoxide (CO) emissions at low and medium loads, but reduced CO emissions at high and full loads, when compared to pure diesel fuel.     

The influence of n-butanol/diesel fuel blends utilization on a small diesel engine performance and emissions

Nitrogen oxides and smoke emissions are the most significant emissions for the diesel engines. Especially, fuels containing high-level oxygen content can have potential to reduce smoke emissions significantly. The aim of the present study is to evaluate the influence of n-butanol/diesel fuel blends (as an oxygenation additive for the diesel fuel) on engine performance and exhaust emissions in a small diesel engine. For this aim five-test fuels, B5 (contains 5% n-butanol and 95% diesel fuel in volume basis), B10, B15, B20 and neat diesel fuel, were prepared to test in a diesel engine. Tests were performed in a single cylinder, four stroke, unmodified, and naturally aspirated DI high speed diesel engine at constant engine speed (2600 rpm) and four different engine loads by using five-test fuels. The experimental test results showed that smoke opacity, nitrogen oxides, and carbon monoxide emissions reduced while hydrocarbon emissions increased with the increasing n-butanol content in the fuel blends. In addition, there is an increase in the brake specific fuel consumption and in the brake thermal efficiency with increasing n-butanol content in fuel blends. Also, exhaust gas temperature decreased with increasing n-butanol content in the fuel blends.     

Performance, emission and combustion evaluation of soapnut oil-diesel blends in a compression ignition engine

Soapnut (Sapindus mukorossi) oil, a nonedible straight vegetable oil was blended with petroleum diesel in various proportions to evaluate the performance and emission characteristics of a single cylinder direct injection constant speed diesel engine. Diesel and soapnut oil (10%, 20%, 30% and 40%) fuel blends were used to conduct short-term engine performance and emission tests at varying loads in terms of 25% load increments from no load to full loads. Tests were carried out for engine operation and engine performance parameters such as fuel consumption, brake thermal efficiency, and exhaust emissions (smoke, CO, UBHC, NO_x, and O₂) were recorded. Among the blends SNO 10 has shown a better performance with respect to BTE and BSEC. All blends have shown higher HC emissions after about 75% load. SNO 10 and SNO 20 showed lower CO emissions at full load. NO_x emission for all blends was lower and SNO 40 blend achieved a 35% reduction in NO_x emission. SNO 10% has an overall better performance with regards to both engine performance and emission characteristics.     

Impact of alcohol-gasoline fuel blends on the performance and combustion characteristics of an SI engine

In this study, the effects of ethanol-gasoline (E5, E10) and methanol-gasoline (M5, M10) fuel blends on the performance and combustion characteristics of a spark ignition (SI) engine were investigated. In the experiments, a vehicle having a four-cylinder, four-stroke, multi-point injection system SI engine was used. The tests were performed on a chassis dynamometer while running the vehicle at two different vehicle speeds (80 km/h and 100 km/h), and four different wheel powers (5, 10, 15, and 20 kW). The results obtained from the use of alcohol-gasoline fuel blends were compared to those of gasoline fuel. The results indicated that when alcohol-gasoline fuel blends were used, the brake specific fuel consumption increased; cylinder gas pressure started to rise later than gasoline fuel. Almost in the all test conditions, the lowest peak heat release rate was obtained from the gasoline fuel use.     

Biodiesel development from high acid value polanga seed oil and performance evaluation in a CI engine

Non-edible filtered high viscous (72 cSt at 40 °C) and high acid value (44 mg KOH/gm) polanga (Calophyllum inophyllum L.) oil based mono esters (biodiesel) produced by triple stage transesterification process and blended with high speed diesel (HSD) were tested for their use as a substitute fuel of diesel in a single cylinder diesel engine. HSD and polanga oil methyl ester (POME) fuel blends (20%, 40%, 60%, 80%, and 100%) were used for conducting the short-term engine performance tests at varying loads (0%, 20%, 40%, 60%, 80%, and 100%). Tests were carried out over entire range of engine operation at varying conditions of speed and load. The brake specific fuel consumption (BSFC) and brake thermal efficiency (BTE) were calculated from the recorded data. The engine performance parameters such as fuel consumption, thermal efficiency, exhaust gas temperature and exhaust emissions (CO, CO₂, HC, NO_x, and O₂) were recorded. The optimum engine operating condition based on lower brake specific fuel consumption and higher brake thermal efficiency was observed at 100% load for neat biodiesel. From emission point of view the neat POME was found to be the best fuel as it showed lesser exhaust emission as compared to HSD.     

Engine performance and exhaust gas emissions of methanol and ethanol-diesel blends

In this study, the effects of methanol-diesel (M5, M10) and ethanol-diesel (E5, E10) fuel blends on the performance and exhaust emissions were experimentally investigated. For this work, a single cylinder, four-stroke, direct injection, naturally aspirated diesel engine was used. The tests were performed by varying the engine speed between 1000 and 1800 rpm while keeping the engine torque at 30 Nm. The results showed that brake specific fuel consumption and emissions of nitrogen oxides increased while brake thermal efficiency, smoke opacity, emissions of carbon monoxide and total hydrocarbon decreased with methanol-diesel and ethanol-diesel fuel blends.     

Effect of hydrogen addition on lean burn performance of a spark-ignited gasoline engine at 800 rpm and low loads

To reduce the fuel consumption and emissions of spark-ignited (SI) engines, hydrogen enrichment was used to improve the performance of a lean burn SI engine operating at low speed and load conditions. A hydrogen port-injection system was mounted on the intake manifolds to introduce hydrogen into the intake ports sequentially while keeping the original gasoline injection system unchanged. A hybrid electronic control unit (HECU) was adopted to control injection timings and durations of gasoline and hydrogen, accomplishing four excess air ratios of 1.00, 1.18, 1.43 and 1.67 and three hydrogen volume fractions in the intake of 3%, 5%, 8%. The experimental results showed that engine brake thermal efficiency and torque output were increased, combustion durations were shortened, cyclic variation and HC emissions were reduced, but NO_x emissions were increased with the increase of hydrogen addition. CO emission was also reduced under lean conditions with hydrogen enrichment.     

Performance and emission characteristics of an CI engine fueled with diesel–biodiesel–bioethanol blends

The paper presents the experimental results obtained concerning performances and pollution of a diesel engine fueled with diesel–biodiesel–ethanol blends compared with diesel fuel in laboratory tests. The main properties of the researched fuels are presented within this paper, in comparison with classical diesel fuel (chemical composition, density, kinematic viscosity, cold filter plugging point, flash point). Engines’ performances were evaluated by determining the brake specific fuel consumption and brake thermal efficiency. For pollution evaluation the emissions of CO, CO₂, NO_x, HC and smoke have been measured. An increasing of brake specific fuel consumption has been observed, especially at lower engines’ loads, with maximum 32.4%, reducing engine brake thermal efficiency with maximum 21.7%. CO emissions decrease, especially at high loads with maximum 59%, on the basis of CO₂ increased emissions. NO_x emissions slightly increase, especially at partial and high loads, meanwhile HC and smoke emissions decrease in all engines’ load cycles.     

Performance and exhaust emission characteristics of a spark ignition engine using ethanol and ethanol-reformed gas

Since ethanol is a renewable source of energy and has lower carbon dioxide (CO₂) emissions than gasoline, ethanol produced from biomass is expected to be used more frequently as an alternative fuel. It is recognized that for spark ignition (SI) engines, ethanol has the advantages of high octane and high combustion speed and the disadvantage of ignition difficulties at low temperatures. An additional disadvantage is that ethanol may cause extra wear and corrosion of electric fuel pumps. On-board hydrogen production out of ethanol is an alternative plan.Ethanol has been used in Brazil as a passenger vehicle fuel since 1979, and more than six million vehicles on US highways are flexible fuel vehicles (FFVs). These vehicles can operate on E85 - a blend of 85% ethanol and 15% gasoline.This paper investigates the influence of ethanol fuel on SI engine performance, thermal efficiency and emissions. The combustion characteristics of hydrogen enriched gaseous fuel made from ethanol are also examined.Ethanol has excellent anti-knock qualities due to its high octane number and a high latent heat of evaporation, which makes the temperature of the intake manifold lower. In addition to the effect of latent heat of evaporation, the difference in combustion products compared with gasoline further decreases combustion temperature, thereby reducing cooling heat loss. Reductions in CO₂, nitrogen oxide (NOx), and total hydrocarbons (THC) combustion products for ethanol vs. gasoline are described.     

Effects of biodiesel on a DI diesel engine performance, emission and combustion characteristics

Experimental tests were investigated to evaluate the performance, emission and combustion of a diesel engine using neat rapeseed oil and its blends of 5%, 20% and 70%, and standard diesel fuel separately. The results indicate that the use of biodiesel produces lower smoke opacity (up to 60%), and higher brake specific fuel consumption (BSFC) (up to 11%) compared to diesel fuel. The measured CO emissions of B5 and B100 fuels were found to be 9% and 32% lower than that of the diesel fuel, respectively. The BSFC of biodiesel at the maximum torque and rated power conditions were found to be 8.5% and 8% higher than that of the diesel fuel, respectively. From the combustion analysis, it was found that ignition delay was shorter for neat rapeseed oil and its blends tested compared to that of standard diesel. The combustion characteristics of rapeseed oil and its diesel blends closely followed those of standard diesel.     

Solubility of a diesel–biodiesel–ethanol blend,its fuel properties,and its emission characteristics from diesel engine

In this work, we studied the phase diagram of diesel–biodiesel–ethanol blends at different purities of ethanol and different temperatures. Fuel properties (such as density, heat of combustion, cetane number, flash point and pour point) of the selected blends and their emissions performance in a diesel engine were examined and compared to those of base diesel. It was found that the fuel properties were close to the standard limit for diesel fuel; however, the flash point of blends containing ethanol was quite different from that of conventional diesel. The high cetane value of biodiesel could compensate for the decrease of the cetane number of the blends caused by the presence of ethanol. The heating value of the blends containing lower than 10% ethanol was not significantly different from that of diesel. As for the emissions of the blends, it was found that CO and HC reduced significantly at high engine load, whereas NO_x increased, when compared to those of diesel. Taking these facts into account, a blend of 80% diesel, 15% biodiesel and 5% ethanol was the most suitable ratio for diesohol production because of the acceptable fuel properties (except flash point) and the reduction of emissions.     

The Impact of Ethanol Fuel Blends on PM Emissions from a Light-Duty GDI Vehicle

This study explores the influence of ethanol on particulate matter (PM) emissions from gasoline direct injection (GDI) vehicles, a technology introduced to improve fuel economy and lower CO₂ emissions, but facing challenges to meet next-generation emissions standards. Because PM formation in GDI engines is sensitive to a number of operating parameters, two engine calibrations are examined to gauge the robustness of the results. As the ethanol level in gasoline increases from 0% to 20%, there is possibly a small (<20%) benefit in PM mass and particle number emissions, but this is within test variability. When the ethanol content increases to >30%, there is a statistically significant 30%–45% reduction in PM mass and number emissions observed for both engine calibrations. Particle size is unaffected by ethanol level. PM composition is primarily elemental carbon; the organic fraction increases from ～5% for E0 to 15% for E45 fuel. Engine-out hydrocarbon and NO_x emissions exhibit 10–20% decreases, consistent with oxygenated fuel additives. These results are discussed in the context of the changing commercial fuel and engine technology landscapes.

Copyright 2012 American Association for Aerosol Research     

Hydrous ethanol vs. gasoline-ethanol blend: Engine performance and emissions

This work compares the performance and emissions from a production 1.0-l, eight-valve, and four-stroke engine fuelled by hydrous ethanol (6.8% water content in ethanol) or 78% gasoline-22% ethanol blend. The engine was tested in a dynamometer bench in compliance with NBR/ISO 1585 standard. The performance parameters investigated were torque, brake mean effective pressure (BMEP), brake power, specific fuel consumption (SFC), and thermal efficiency. Carbon monoxide (CO), carbon dioxide (CO₂), hydrocarbons (HC) and oxides of nitrogen (NO_X) exhaust emissions levels are also presented. The results showed that torque and BMEP were higher when the gasoline-ethanol blend was used as fuel on low engine speeds. On the other hand, for high engine speeds, higher torque and BMEP were achieved when hydrous ethanol fuel was used. The use of hydrous ethanol caused higher power at high engine speeds, whereas, for low engine speeds, both fuels produced about the same power. Hydrous ethanol produced higher thermal efficiency and higher SFC than the gasoline-ethanol blend throughout all the engine speed range studied. With regard to exhaust emissions hydrous ethanol reduced CO and HC, but increased CO₂ and NO_X levels.     

Feasibility of blending karanja vegetable oil in petro-diesel and utilization in a direct injection diesel engine

Karanja (Pongamia pinnata) oil, a non-edible high viscosity (27.84 cSt at 40 °C) straight vegetable oil, was blended with conventional diesel in various proportions to evaluate the performance and emission characteristics of a single cylinder direct injection constant speed diesel engine. Diesel and karanja oil fuel blends (5%, 10%, 15%, and 20%) were used to conduct short-term engine performance and emission tests at varying loads (0%, 20%, 40%, 60%, 80%, and 100%). Tests were carried out over the entire range of engine operation and engine performance parameters such as fuel consumption, thermal efficiency, exhaust gas temperature, and exhaust emissions (smoke, CO, CO₂, HC, NO_x, and O₂) were recorded. The brake specific energy consumption (BSEC), brake thermal efficiency (BTE), and exhaust emissions were evaluated to determine the optimum fuel blend. Higher BSEC was observed at full load for neat petro-diesel. A fuel blend of 10% karanja oil (KVO10) showed higher BTE at a 60% load. Similarly, the overall emission characteristics were found to be best for the case of KVO10 over the entire range of engine operation.     

Experimental study on the auto-ignition and combustion characteristics in the homogeneous charge compression ignition (HCCI) combustion operation with ethanol/n-heptane blend fuels by port injection

This article investigates the auto-ignition, combustion, and emission characteristics of homogeneous charge compression ignition (HCCI) combustion engines fuelled with n-heptane and ethanol/n-heptane blend fuels. The experiments were conducted on a single-cylinder HCCI engine using neat n-heptane, and 10%, 20%, 30%, 40%, and 50% ethanol/n-heptane blend fuels (by volume) at a fixed engine speed of 1800 r/min. The results show that, with the introduction of ethanol in n-heptane, the maximum indicated mean effective pressure (IMEP) can be expanded from 3.38 bar of neat n-heptane to 5.1 bar, the indicated thermal efficiency can also be increased up to 50% at large engine loads, but the thermal efficiency deteriorated at light engine load. Due to the much higher octane number of ethanol, the cool-flame reaction delays, the initial temperature corresponding the cool-flame reaction increases, and the peak value of the low-temperature heat release decreases with the increase of ethanol addition in the blend fuels. Furthermore, the low-temperature heat release is indiscernible when the ethanol volume increases up to 50%. In the case of the neat n-heptane and 10% ethanol/n-heptane blends, the combustion duration is very short due to the early ignition timing. For 20–50% ethanol/n-heptane blend fuels, the ignition timing is gradually delayed to the top dead center (TDC) by the ethanol addition. As a result, the combustion duration prolongs obviously at the same engine load when compared to the neat n-heptane fuel. At overall stable operation ranges, the HC emissions for n-heptane and 10–30% ethanol/n-heptane blends are very low, while HC emissions increase substantially for 40% and 50% ethanol/n-heptane blends. CO emissions show another tendency compared to HC emissions. At the engine load of 1.5–2.5 bar, CO emissions are very high for all fuels. Beside this range, CO emissions decrease both for large load and light load. In terms of operation stability of HCCI combustion, for a constant energy input, n-heptane shows an excellent repeatability and light cycle-to-cycle variation, while the cycle-to-cycle variation of the maximum combustion pressure and its corresponding crank angle, and ignition timing deteriorated with the increase of ethanol addition.     

Comparative performance and emissions of IDI-turbo automobile diesel engine operated using degummed, deacidified mixed crude palm oil-diesel blends

The performance and emissions of an indirect injection (IDI)-turbo automobile diesel engine operated with diesel and blends of degummed-deacidified mixed crude palm oil in diesel at portions of 20, 30, and 40 vol.% are examined and compared at various loads and speeds. Although fuel properties of the tested blends do not exactly meet all regulations of Thailand, they are all able to operate the engine. Comparing this with diesel, especially at full loads, shows that all blends produce the same maximum brake torque and power. A higher blending portion results in a little higher brake specific fuel consumption (+4.3% to +7.6%), a slightly lower brake thermal efficiency (-3.0% to -5.2%), a slightly lower exhaust gas temperature (−2.7% to −3.4%), and a significantly lower amount of black smoke (−30% to −45%). The level of carbon monoxide from the 20 vol.% blend is significantly lower (−70%), and the levels of nitrogen oxides from all blends are little higher.     

Combustion of n-butanol in a spark-ignition IC engine

Alcohols, because of their potential to be produced from renewable sources and because of their high quality characteristics for spark-ignition (SI) engines, are considered quality fuels which can be blended with fossil-based gasoline for use in internal combustion engines. They enable the transformation of our energy basis in transportation to reduce dependence on fossil fuels as an energy source for vehicles. The research presented in this work is focused on applying n-butanol as a blending agent additive to gasoline to reduce the fossil part in the fuel mixture and in this way to reduce life cycle CO₂ emissions. The impact on combustion processes in a spark-ignited internal combustion engine is also detailed. Blends of n-butanol to gasoline with ratios of 0%, 20%, and 60% in addition to near n-butanol have been studied in a single cylinder cooperative fuels research engine (CFR) SI engine with variable compression ratio manufactured by Waukesha Engine Company. The engine is modified to provide air control and port fuel injection. Engine control and monitoring was performed using a target-based rapid-prototyping system with electronic sensors and actuators installed on the engine [1]. A real-time combustion analysis system was applied for data acquisition and online analysis of combustion quantities. Tests were performed under stoichiometric air-to-fuel ratios, fixed engine torque, and compression ratios of 8:1 and 10:1 with spark timing sweeps from 18° to 4° before top dead center (BTDC). On the basis of the experimental data, combustion characteristics for these fuels have been determined as follows: mass fraction burned (MFB) profile, rate of MFB, combustion duration and location of 50% MFB. Analysis of these data gives conclusions about combustion phasing for optimal spark timing for maximum break torque (MBT) and normalized rate for heat release. Additionally, susceptibility of 20% and 60% butanol-gasoline blends on combustion knock was investigated. Simultaneously, comparison between these fuels and pure gasoline in the above areas was investigated. Finally, on the basis of these conclusions, characteristic of these fuel blends as substitutes of gasoline for a series production engine were discussed.     

Performance and emissions analysis on diesel engine fuelled with cashew nut shell biodiesel and pentanol blends

We studied the impact of blending pentanol, a next generation biofuel, with cashew nut shell biodiesel on its performance and emissions characteristics in a constant speed compression ignition engine. Our main objective was to reduce CO, HC, NO _X and smoke emission when fueled with neat cashew nut shell biodiesel and the pentanol blends. Cashew nut shell oil is a byproduct from cashew nut industry. Since it is nonedible, it can be used as a promising alternative. Conventional transesterification process was used to convert the cashew nut shell oil into cashew nut shell biodiesel. Pentanol with 98.4% purity was used as an oxygenated additive. The experiment involved three test fuels: neat cashew nut shell biodiesel (C100), Pentanol blended with cashew nut shell biodiesel by 10% volume (C90P10) and Pentanol blended with cashew nut shell biodiesel by 20% volume (C80P20). The feasibility of using neat biofuel (without adding diesel) was also investigated. Experimental work concluded that the test fuels used in this study does not require any modification in engines. In addition, the combustion of fuels was smooth and there was no physical and visible damage in the engine components when fueled with cashew nut shell biodiesel and the pentanol blends. By adding 10% and 20% of pentanol to cashew nut shell biodiesel, significant reduction in CO, HC, NO _X and smoke emission was observed. In addition, brake thermal efficiency increased marginally with slight reduction in brake specific fuel consumption.