Patent ID: 6966295

Claim:
A compression ignition internal combustion engine comprising a combustion chamber to which air and fuel are supplied, an intake valve for opening and closing a passage between said combustion chamber and an intake port communicating with said combustion chamber, and an exhaust valve for opening and closing a passage between said combustion chamber and an exhaust port communicating with said combustion chamber in which the temperature and pressure in said combustion chamber are increased to self-ignite an air-fuel mixture with the compressive operation of a piston only after supplying an ignition trigger factor and after closing of said intake valve, means for injecting said ignition trigger factor directly into said combustion chamber at an arbitrary timing in a state in which said intake valve and said exhaust valve are closed, depending on operating conditions of said compression ignition internal combustion engine so that an air-fuel mixture under a compression or expansion stroke of the piston is brought into an ignitable state, said ignition trigger factor being gas having a pressure higher than a pressure in said combustion chamber at the time of ignition-trigger-factor injection and means for controlling at least one of an injection timing, an injection amount, and an injection pressure of the ignition trigger factor depending on the operating conditions.