Patent ID: 6009861
Filing Date: 2000-01-04
Classification: F02B,F02D,F02F,F02M,Y02T

Abstract:
A method of improving combustion characteristics of a four-stroke internal combustion engine, wherein the internal combustion engine comprises a cylinder with a combustion chamber, an inlet valve, and an exhaust valve; a piston reciprocatingly moveable in the cylinder and delimiting one end of the combustion chamber; an induction device and an exhaust device; said method comprising the steps of:a) opening the inlet valve to provide communication between the combustion chamber and the induction device during the intake stroke of the engine;b) temporarily closing the exhaust valve, provided to temporarily provide communication between the combustion chamber and the exhaust device, for terminating an exhaust stroke of the engine after the piston has reached the top dead center;c) providing a flow passage along the at least partially open exhaust valve, wherein in the low load range of the engine, after exhausting of the exhaust gas, an exhaust gas backflow is directed into the combustion chamber such that the exhaust gas backflow rotates about an axis and forms an exhaust gas envelope surrounding the combustion chamber;d) introducing a fresh charge into a radially inner region of the exhaust gas envelope rotating about the axis so that the fresh charge is thus separated by the exhaust gas envelope from the combustion chamber wall at the time of combustion.