Patent ID: 7347180

Claim:
A method of operating an internal combustion engine with a variable compression ratio, said engine having a cylinder, a cylinder head including inlet and outlet valves, a piston movably disposed in the cylinder and defining a combustion chamber between the cylinder head and the piston, to which fresh air is supplied via an intake manifold, said method comprising the steps of operating the internal combustion engine in a compression ignition or in a spark ignition operating mode depending on the engine operating point, wherein, in a compression mode, exhaust gas is retained in the combustion chamber and compressed during a charge change, and a first fuel quantity is injected into the retained exhaust gas by means of a first injector arranged in the combustion chamber, a second fuel quantity is subsequently fed to the combustion chamber, and the compression ratio ε=(V h +V c )/V c of the internal combustion engine is set higher in the compression ignition mode than in the spark ignition mode of operation, (V h +V c being the cylinder volume when the piston is at the bottom of its stroke and V c being the cylinder volume when the piston is at the top of its stroke).