Daimler Ag

Matthias Werner

Christoph Lux

Michael Oechsle

In a method for operating a spark-ignition, direct-injection internal combustion engine, wherein fuel is injected into a cylinder of the internal combustion engine and is ignited by a spark plug as a function of at least the load of the internal combustion engine, a crank angle is determined at which a first amount of fuel is injected into the cylinder during the intake stroke whereby a lean mixture is formed in the cylinder, subsequently, as a function of at least the load of the internal combustion engine, a crank angle is determined at which a second amount of fuel is injected, whereby a mixture cloud, which is richer than the lean mixture is formed in the lean mixture and a third amount of fuel is injected in the form of a stratified injection for forming a locally enriched and ignitable fuel/air mixture in the region of the spark plug close to an ignition time which is then ignited by the spark plug causing also combustion of the mixture cloud and the lean mixture.

Method of operating a spark ignition internal combustion engine

In a method for cold-running or warm-up operation of a spark-ignition, direct-injection 4-stroke internal combustion engine having an exhaust gas catalytic converter, wherein fuel is injected into the cylinders of the internal combustion engine by means of injectors and is externally ignited by means of spark plugs, in an intake stroke fuel injection a lean, combustible but non-ignitable lean mixture is produced in the cylinders, in a compression stroke fuel injection following the intake stroke injection, by a compression stroke fuel injection, a combustible and ignitable fuel/air mixture is formed in the combustible but non-ignitable lean mixture in the cylinders and, subsequently, in a stratified fuel injection which is close in timing to an ignition time, a rich fuel/air mixture is locally formed in the region of the spark plug and is then ignited by the spark plug so as to provide for rapid heat up of the cold exhaust gas catalytic converter with reliable combustion and smooth engine operation.

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Stuttgart, Germany

Matthias Werner