Patent ID: 7614383

Claim:
A method for cold-running and warm-up operation of a spark-ignition, direct-injection 4-stroke internal combustion engine having a cylinder head with an exhaust duct ( 18 ) including an exhaust gas catalytic converter ( 1 ), and a fuel injection system for the injection of fuel ( 2 ) into a cylinder ( 4 ) of the internal combustion engine via an injector ( 3 , 26 ) and an injection system with a spark plug ( 5 , 24 ) arranged in the cylinder head, comprising the steps of: injecting a first injection amount of fuel ( 2 ) into the cylinder ( 4 ) during an intake stroke ( 6 ) as an intake stroke injection ( 9 ) so as to form a lean, combustible but non-ignitable lean mixture ( 13 ) in the whole cylinder ( 4 ) of the engine; injecting a second injection amount of fuel ( 2 ) during a compression stroke ( 7 ) following the intake stroke ( 6 ), as a compression stroke injection ( 10 , 29 ) in which a combustible and ignitable fuel/air mixture is produced in part of the non-ignitable lean mixture ( 13 ) previously established in the cylinder; subsequently injecting a third injection amount of fuel ( 2 ) in the form of a stratified injection ( 11 , 31 ) close in terms of timing to an ignition time ( 12 , 32 ) so as to form in the combustion and ignitable fuel/air mixture a fuel/air mixture cloud ( 11 , 31 ) which is enriched locally in the region of the spark plug ( 5 , 24 ), and igniting said locally enriched fuel/air mixture cloud ( 11 , 31 ) by the spark plug ( 3 , 26 ).