In – Cylinder Pressure Measurement And Combustion Analysis Of A CNG Fuelled Si Engine Testing

Abstract

Abstract : Numerous attempts to use natural gas in engine have succeeded, but further development is still needed. Many applications to date have been based on retrofitting spark ignition or diesel engines and have failed to maintain the brake specific fuel (bsfc), or power density (kW/litre of engine displacement) of the base engine used. However, even thought these attempts have not captured the optimum advantages of natural gas, they still are an improvement over the base engine in fuel costs and emissions. The UTM CNG Engine Research Group has already performed research in this alternative fuel in SI engine, either in single cylinder research engine or within four cylinders commercial based engine. To have a clear understanding of the CNG fuelled engine characteristics, a pressure transducer has installed on one of the modified cylinder heads. Along with this, the crank angle encoder was also fit to measure the angle of the crankshaft and top dead centre (TDC) position. A Data Acquisition System (DAS) consist of charge and voltage module, signal conditioner and DAQ plug-in card, was also set up and was supported by the software to enable data processing. The results show that in term of pressure rise and burn rate, the CNG operation produced a slightly differences compared to that of gasoline. The results also confirmed the lower flame speed CNG characteristic’s with longer combustion period needed. Although, produced lower pressure rise compared to gasoline operation, the CNG fuelled engine generated less emission.

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