The increasing energy demand, surging oil prices, depleting oil reserves and environmental pollution problems associated with the use of fossil fuels have sparked renewed interest to find out clean alternative fuels. Alcohols such as methanol, ethanol and butanol are competitive alternative fuels due to their liquid nature, high oxygen contents, high octane number and their production from renewable biomass. In this review, the fuel properties of these alcohols are compared with conventional gasoline and diesel fuel. The comparison of fuel properties represents that butanol has the potential to overcome the problems associated with the use of methanol and ethanol. Progresses of their production from different sources are also introduced. Further, several techniques such as alcohol–diesel fuel blends and alcohol–diesel fuel emulsions are discussed, especially for lower alcohols, in order to use them in diesel engines. The effects of diesel–alcohol blends on the combustion, performance and emissions of diesel engines are also analyzed. It is examined that blending of alcohols, along with some CN improver, to diesel fuels can reduce diesel engine emissions without adverse impacts on the performance of diesel engines. These studies also reveal that butanol is a better alternative for diesel fuel due to its superior fuel properties and miscibility with diesel fuel than those of methanol and ethanol. Finally, some critical conclusions and future research directions are highlighted.

Advances in diesel–alcohol blends and their effects on the performance and emissions of diesel engines

Performance, emission and combustion characteristic of a multicylinder DI diesel engine running on diesel–ethanol–biodiesel blends of high ethanol content

The aim of this review is to study the opportunities and prospects of introducing diesel–biodiesel–ethanol/bioethanol blend as fuel in the existing diesel engines. The study is based on the engine emissions and its performance. The energy policies and the ever growing energy demand of the world, require an alternative to fossil fuels. In this quest, the diesel–ethanol blend or the diesohol blend might be a good option. But this blend possesses stability problem as well as inferior physicochemical properties when compared to diesel fuel and needs additives to remain stable. When biodiesel is used as an additive in this diesohol blend, it improves the physicochemical properties of the ternary blend, engine performance and also increases the renewable portion of the blend. First the engine performance and emissions data found by using diesel–biodiesel–ethanol/bioethanol ternary blends are accumulated. Then the results of the scientists and investigators are discussed to evaluate its potential as an alternative to fossil diesel fuel. The physicochemical properties of ternary blends are found to be almost similar to the diesel fuel. These ternary blends significantly reduce the PM (particulate matter) emissions from the diesel engine but the emissions of NO x (nitrogen oxides), soot and smoke, HC (hydrocarbon), CO (carbon monoxide), CO 2 (carbon dioxide) and the carbonyl compounds depend on the operating conditions of the engine and remain almost similar to the diesel fuel exhaust.

Performance and emission assessment of diesel-biodiesel-ethanol/bioethanol blend as a fuel in diesel engines: a review.

The purpose of this study is to investigate the impacts of diesel–biodiesel–alcohol blends on the combustion, performance and emissions characteristics of a single-cylinder diesel engine. Tests were conducted at different engine speeds of 1750, 2250, 2750 and 3250 rpm and under full load. In this study, different fuels [called as reference diesel (D100), 20 vol% cottonseed methyl ester (D80C20), 10 vol% ethanol (D90E10) and finally the ternary type of their derivations (D70C20E10)], were used. The experimental results showed that the highest reduction values were observed on CO emission by 42%, 30% and 8% for the D90E10, D70C20E10 and D80C20 fuels, respectively. These reductions for HC emission were achieved as 40%, 31% and 23% for the D90E10, D70C20E10 and D80C20, respectively. On the other hand, the reductions of NOx and CO2 emissions were not sharp and varied between 2–7%. Besides the reductions on the exhaust emissions, biodiesel–ethanol blend presented better results in terms of HRRmax and CPmax than using biodiesel alone. Additionally, ignition delay of the biodiesel blends was longer than that of D100 fuel owing to their low cetane numbers. Combustion duration was shortened with the increment in engine speed because the turbulence increased in the combustion chamber at high engine speed. This case also improved the homogeneity of test fuels and increased the quality of the combustion process. As a consequence, this paper clearly reported that it is possible to achieve fewer emissions, the highest CPmax values with the presence of ethanol in biodiesel fuels rather than using biodiesel alone for diesel engines.

Experimental investigation of combustion, performance and emission characteristics of a diesel engine fuelled with diesel–biodiesel–alcohol blends

Yogesh Aghav

Papers

Effects of Ethanol Addition on Performance, Emission and Combustion of DI Diesel Engine Running at Different Injection Pressures

Development of Two Stage Turbo-Charging for Medium Duty Diesel Engine of Power Generation Application

Efficient Approach for Optimization of Piston Bowl Shape, Compression Ratio and EGR for DI Diesel Engine

Effect of Piston Cavity Geometry on Combustion, Emission and Performance of a Medium Duty DI Diesel Engine

Improving the Reliability of Piston for Increased Power Density by Changing the Shape of Piston Bowl for a Medium Speed Heavy Duty Diesel Engine