Diesel or petrol IC engine with at least two cylinder groups and catalyst

摘要

The engine has at least two separately working groups of cylinders (2,3) one of which can be switched off for economy running e.g. in city centres. Both exhaust systems has catalysts (8,9). When one group of cylinders is switched off i.e. no fuel feed, the exhaust gasses from the other part of the engine are ducted back into the inlet manifold of the non working part. This maintains the catalyst at the working temperature, ready for instant switch on. The exhaust lines are fitted with flow diverting valves (15,16) operated by a processor control (14) which controls the operation of the engine. For multiple groups of cylinders the exhaust lines are fed into a manifold from where exhaust gas is ducted back to selected groups of cylinders by separate control valves.