Method of reducing exhaust gas emissions during cold start conditions and an internal combustion engine in which the method is used

摘要

An internal combustion engine and a method of reducing hydrocarbon emissions of an internal combustion engine during cold start conditions in disclosed. The engine has at least one cylinder provided with a piston which reciprocates between a top dead-center and a bottom dead-center, at least one intake valve through which intake air is provided, a fuel injector assembly arranged to inject atomised fuel particles directly into the cylinder and means for controlling the opening and closing of the intake valve. According to the invention, intake valve opening is adjusted to occur after top dead center of the piston. When the intake valve opens, a pressure differential exists across the valve. Fuel is injected directly into the cylinder during the time of the pressure differential.