Abstract: A cooling system for a motor vehicle engine includes a heat exchanger, ducting connecting the engine and the heat exchanger in a closed circuit, and a pump for circulating coolant fluid in the circuit. The heat exchanger is arranged to act as a condenser when required, and the pump is an electric pump which circulates the coolant fluid between the engine and the heat exchanger. The system includes a three-way thermostatic valve, which causes the fraction of the cooling fluid delivered into the heat exchanger, in relation to the constant flow passing through the engine, to be varied progressively from 0 to 100%. When the engine is working at its highest power, the fluid vaporises in the engine and condenses in the heat exchanger, while at lower power levels the heat exchanger operates like a conventional cooling radiator.

Abstract: The invention relates to a motor vehicle heat exchagner, the heat exchanger comprising a fluid box (10) having the ends of tubes (22) opening out therein, said tubes constituting a heat exchange bundle located inside an envelope (24). Engine exhaust gases flow through said box (10) and said tubes (22), and engine cooling liquid or cabin heater air flow through said envelope (24). The envelope is connected to the fluid box (10) by a tubular element (30) and a perforated plate (18). The envelope (24) is made of a lightweight material which need not be capable of witstanding exhaust gas temperatures.

Abstract: Combustion engine cooled by circulation of liquid in a main circuit which includes a pump and a radiator associated with an expansion-tank. Auxiliary piping connects the expansion-tank to a suitable point in the main circuit in order to inject into it a flow of cold liquid coming from the expansion-tank and delivered through an auxiliary pump.