Heat exchanger for a heat pump driven by an internal combustion engine

In heat exchangers which extract heat from the hot exhaust gas of internal combustion engines and dissipate it to a second medium, it is disadvantageous that the exhaust gas temperature varies strongly in the various operating states of the internal combustion engine, so that for an exhaust gas at a low temperature the formation of exhaust gas condensate comes about, while at high exhaust gas temperatures the possibility of thermal energy exchange is not fully exhausted. The invention creates a capacity-controlled heat exchanger which permits optimum heat utilisation while largely avoiding the formation of exhaust gas condensate. This is achieved when the heat exchanger has a control member which is acted on by one or more controlled variable(s), and this control member effects control of the quantity of at least one medium flowing through the heat exchanger.