Method for detoxifying the exhaust of multi-cylinder mixture-compressing internal combustion engines

摘要

Methods involving exhaust gas recirculation into the air or mixture intake systems and the addition of secondary air to the exhaust system are known. In these methods, the secondary air reaching the intake system via the exhaust gas recirculation system partially cancels out the reduction in nitrogen oxides which is achieved without the addition of secondary air. The object was to find measures by means of which the sum of the nitrogen-oxide and hydrocarbon fractions in the exhaust gas can be reduced. These measures consist in that exhaust gas is recirculated to the intake system from only one exhaust line of a single cylinder and that there is either no addition of secondary air to this exhaust line or only a restricted addition compared with the other lines. The invention makes possible improved detoxification of the exhaust gas without the need for additional equipment.