Patent ID: 7155899

Claim:
A method for heating an exhaust gas catalyst of an internal combustion engine having, an inlet tract with a throttle valve arranged within the inlet tract, a combustion chamber with gas exchange valves in the form of an inlet and outlet valve, an exhaust line with an exhaust gas catalyst arranged the exhaust line, a blower device for pre-compressing the air supplied to the combustion chamber, a device for setting the valve overlap and valve lift of the gas exchange valves, an injection valve for injecting fuel directly into the combustion chamber, a device that determines the amount of fuel required to be injected for homogenous operation of the internal combustion engine, and after detection of a cold-start of the internal combustion engine, comprising: switching to a lower valve lift and increasing the induction manifold pressure by completely opening the throttle valve and pre-compression of the air by supercharging, in order to generate a positive pressure drop from the inlet side to the outlet side of the internal combustion engine; setting the valve overlap of the gas exchange valves in order to deliver at least part of the air supplied by the blower device as flushing air directly from the inlet side to the outlet side of the internal combustion engine in the exhaust line; injecting fuel directly into the combustion chamber and after closure of the outlet valve, the injected fuel mixing with an air mass remaining in a cylinder; combusting the mixed injected fuel and air mass to produce a gas having a λ cyl less than 1 and exhausting the gas from the combustion chamber into the exhaust line; and mixing the exhausted gas with flushing air to produce a mixture having a λ ex greater than λ cyl to improve CO and HC concentrations and residual oxygen content for heating the exhaust gas catalyst.