| 摘要 |
An automotive engine cooling system 10 includes a first fluid flow circuit 14 and a second fluid flow circuit 16. The second fluid flow circuit provides a circuit for fluid flow which is entirely separate from the first flow circuit. A first pump 18 operates to pump a first coolant fluid around the first fluid flow circuit and a second pump 20 operates to pump a second coolant fluid around the second fluid flow circuit. A prime mover 22 is connected to both the first and second pumps such that operation of the prime mover causes both the first and second pumps to pump coolant fluid around the first and second circuits respectively. Preferably, the prime mover is the engine being cooled by the cooling system, where the engine may be connected to the pumps by means of a rotating drive shaft (46, fig. 1). One or both of the first and second pumps may comprise a pump rotor or impeller (28, 30; fig.1). The coolant may be water or a water based liquid coolant such as a mixture of water and ethylene glycol. The first fluid flow circuit preferably extends along cooling passages in or around the engine, where the circuit may include a radiator 52 and a thermostatically controlled valve 53. The second fluid flow circuit preferably includes a liquid to gas heat exchanger, in which the second coolant cools a gas flowing through the heat exchanger, and may also include a radiator 60. Preferably, the heat exchanger is an exhaust gas recirculation (EGR) cooler 54 or a charge air cooler 56 which acts as an inter-cooler for the fresh air drawn into the engine by a turbo unit 58. |
