2014/5/8 下an clutch(风扇高合船 75 Thermostat节温播， 凡冷大复 同物大汽卓国 窗凡冷法气 得结大究面 合R冷大写 7.6 Water Pur四即水泵 单面rja mtr that ains特辆nd @及冷大复 /用 阳新大摩汽原平滑 大代甲用 7,701Co0iag机袖冷却) InAAmResta 包月冷去？ 同将大弹汽摩帽 鸭著大示究率酒 @R冷大 阳密大究中酒 32014/5/8 3 19/27 同济大学汽车学院 Fan clutch (风扇离合器) For the engine is not always working at high temperature, so we take use of the fan clutch to control the state of radiator fan, which will reduce some power loss. The clutch mainly contains silicone oil clutch(硅油离合器) and electromagnetic clutch(电磁式离合器). 20/27 同济大学汽车学院 7.5 Thermostat (节温器) The thermostat helps the engine reach operating temperature by preventing coolant from circulating to the radiator, thus allowing the engine to heat up more quickly. As the engine reaches operating temperature, the thermostat opens and allows coolant to flow through the radiator. <76℃ >89℃ 21/27 同济大学汽车学院 Close(small cycle) Open (big cycle) Wax-type thermostat（蜡 式节温器）takes use of the feature of paraffin(石 蜡) that it extends after heated from solid to liquid and pushes the spring to switch the water passage. Thermostat using an electric heating of wax element has been created. The thermostat position can be set independently of the current coolant temperature on the basis of set point from an engine map. video 22/27 同济大学汽车学院 23/27 同济大学汽车学院 Schematic water cooling cycles 24/27 同济大学汽车学院 7.6 Water Pump (水泵) The water pump circulates coolant through the system via an impeller (a rotor that spins to move fluid). Centrifugal water pump（离心式水泵） is widely used. 25/27 同济大学汽车学院 When the impeller is rotating , the water in pump rotates with the impeller and is driven to the edge of the impeller under the action of centrifugal force (离心力). So the water is pumped into water jacket leading to the formation of low-pressure area in the center of pump. Then the cold water from radiator is sucked into the pump. 26/27 同济大学汽车学院 7.7 Oil Cooling (机油冷却) Part of the heat from engine is absorbed by the lubricating oil. With some powerful engines, temperature of oil could be too high. So the oil cooler has to be employed. In addition, to keep the engine cool, on cars with an automatic transmission(自动 变速器), the radiator is equipped with a separate heat exchanger to keep transmission fluid from boiling over. Coolant is circulated through the oil cooler to absorb the heat from the lubricating oil. 27/27 同济大学汽车学院 Heat is transferred to the lubricating oil as it passes around engine components such as bearings and pistons. Oil cooler is used to dissipate heat from the oil to maintain optimum temperatures for proper lubrication. It is actually a heat exchanger. Heat from hot oil flowing through the oil cooler is absorbed by the cold water from radiator. Then the cooled oil is driven into engine