Internal combustion engine providing improved exhaust-gas purification

摘要

In an internal combustion engine having a plurality of sequentially operative combustion chambers, harmful components in exhaust gases are reduced. At least one of the combustion chambers is supplied with a rich mixture having a smaller air-to-fuel ratio than the stoichiometric air-to-fuel ratio and the remaining combustion chambers are fed with a lean mixture whose air-to-fuel ratio is greater than the stoichiometric air-to-fuel ratio. At the point where the exhaust gases emitted from the combustion chambers gather, the total air-to-fuel ratio of the rich and lean mixtures is detected producing a signal representing the total air-to-fuel ratio. One of the rich and lean mixtures is controlled in accordance with the air/fuel ratio signal to maintain the total air-to-fuel ratio practically at a predetermined value.