The Experimental Investigation of the Effects of Operating Parameters on Exhaust Emissions on a Spark Ignition Engine

Air pollution is one of the major problems threatening human health. Emissions, such as CO, HC and NOx, from the internal combustion engines have an important effect on air pollution. Emissions have been tried to be kept below the determined levels by the authorities. In this study, the effects of variation of air/fuel ratio, ignition timing, compression ratio and inlet air temperature on exhaust emissions were investigated experimentally on a four-stroke, single cylinder, spark ignition engine with variable compression ratio and fuel injection. The most effective parameter on the emissions is air/fuel ratio and can not be observed considerable decreasing after the more lean section than 10% on CO and HC. Increasing compression ratio HC emissions increase. With increasing ignition timing; CO emissions decrease and HC emissions increase up to 30 degrees crank angle and then decrease.