Demand for cleaner, cheaper and renewable alternate fuel sources has opened a lot of new avenues in area of automotive fuels. Moving away from the existing dependency on the fossil fuels with a stress on the renewable sources and eco-friendliness has become one of the key-driver for the development. Ever increasing cost and limited availability of the fossil fuels has led many automotive manufacturers to look at alternate sources for fuel. Some important alternate fuels like biogas, vegetable oil and its esters, alcohols, compressed natural gas (CNG), liquefied petroleum gas (LPG) and hydrogen are rapidly finding a place in automotive applications.
Ethyl alcohol popularly known as ethanol, produced from renewable energy sources like biomass has been tested extensively in internal combustion engines. Due to the high latent heat of evaporation, high octane number and high flammability temperature, ethanol has positive influence on the engine performance. Its oxygen content helps to reduce the negative effect of fossil fuels on environment. Due to these advantages, gasoline doped with ethanol (in varying levels) has become a promising fuel option. The amount of alcohol content in gasoline, determines the level of modifications required to make existing engines compatible. Earlier studies indicate that 5% ethanol (in short E5) can be used directly without any modifications. Higher levels require changes in the system.
This paper investigates the compatibility of a 4 cylinder, 1.4L MPFI engine meeting Bharath Stage 3 norms (equivalent to Euro 3) with 10% ethanol blended gasoline. Experiments were conducted to investigate the effect of E10 (Ethanol 10%, rest gasoline) blend on engine performance, emission compliance, startability (ambient, cold temperature and hot soak) and durability (components and emission degradation). Material compatibility study was also done to find the behaviour with E10 fuel.
Comparative emission tests with neat gasoline and E10 blend shows a net decrease in diluted carbon monoxide (CO) by 13% with E10 blends. Total hydrocarbon emissions (THC) were found to decrease by 19% and oxides of nitrogen (NOx) emissions increases by 16%. There is a net reduction in carbon dioxide (CO2) by 2% compared to neat gasoline. By utilizing the higher octane rating of E10 blend, it is possible to improve the wide open throttle (WOT) torque characteristics of engine making it at par with neat gasoline. In general, with the usage of E10 fuel, there is a net reduction in CO, THC & CO2 emissions without major deterioration in engine performance.