The exhaust gas cleaning device for an IC engine, partic. a diesel engine, has a catalytic convertor (1) located in its exhaust system. A heat exchanger (2) is located upstream of the catalytic convertor, and is used to regulate the gas temperature to the optimum temperature region at which the catalytic convertor has its optimum efficiency. The heat exchanger is also used to limit the maximum temperature of the exhaust gases. The medium used to regulate the gas temperature can be air (L) or cooling water taken from the engine.
