Method for reducing the pollutant emission of an internal combustion engine

Abstract

The method according to the invention is based on the discovery that the pollutant emissions in the first minutes of operation of an internal combustion engine also depend on the preceding operation and switching off procedure. It is suggested to subject the internal combustion engine and the catalytic converter to a cleaning or a scavenging phase before the standstill of the motor. With this cleaning or scavenging phase the movement of the internal combustion engine is still maintained for a certain time before standstill of the motor either by sparking or by an external drive and at least temporally in at least individual cylinders of the internal combustion engine the supply of fuel is interrupted and exclusively air is delivered. By way of this it is achieved that the remaining pollutants accumulated in the internal combustion engine are supplied to the catalytic converter which is still at the operating temperature and the catalytic converter is enriched with oxygen. For example one may let the internal combustion engine run out, by which means its rotational speed (n) from the beginning of the scavenging procedure (t1) to the standstill of the motor (t2) continuously decreases.

Dependencies are inferred from the claim text.