Simulation studies on the performance of small engine fuelled by methane and the effect of various valve timings

Abstract

Over the past few years, many researchers have conducted experimental and simulation studies using alternative fuels for internal combustion engine. There are many types of existing alternative fuels can be used in internal combustion engine, but the fundamental information about their combustion process is still limited due to difficulties in developing the experimental work. This study focus on the performance of methane fuelled engine and optimize it by varying the cam timing angle for both intake and exhaust valves. The engine performance was measured on the brake torque, brake power, brake mean effective pressure (Bmep) and incylinder peak pressure. The engine model was developed based on Modenas Kriss 110cc 4-stroke single cylinder gasoline engine. CATIA software was used in developing the 3D engine model and followed by utilization of GT-Suite software in analyzing the engine performance. The engine performance results for methane fuelled engine were found to be lower at about 20.1 % for engine torque, brake power and bmep and 12.0 % for in-cylinder peak pressure when compared to gasoline engine. In the case of different valve timing, it was found that retarding the exhaust valve open timing at about 10° would produce the highest brake power in the range 5 – 10 %. From these results it can be concluded that the methane fuel produced lower engine performance compared to gasoline and different cam timing angle is required for methane fueled engine.