A study of HC emission from a spark ignition engine. (The influence of fuel absorbed into cylinder lubricating oil film)

Abstract

The effect of the cylinder lubricating oil film on unburned hydrocarbon (HC) emissions from a spark ignition engine was investigated. A lubricant-free piston ring and cylinder were employed to study the interaction between the fuel and the oil film. Absorption and desorption of fuel vapor into and from the oil film was found to account for about 25-30 percent of the total unburned HC emissions. The variation of the concentration of combustion gases and unburned hydrocarbons in the combustion chamber and exhaust port were also studied, during the combustion, expansion and exhaust strokes, by means of high speed sampling valves. The HC concentration in the combustion chamber was found to increase during the expansion and exhaust strokes.