SEASpecial English for Automobile CHAPTER INTERNAL COMBUSTION ENGINE Review 1: Whats the function of the cooling system? Review 1: Whats the function of the cooling system? To take away the heat from the cylinder and working parts of an engine To maintain proper engine temperature SEASpecial English for Automobile CHAPTER INTERNAL COMBUSTION ENGINE Liquid Coolingair Cooling SEASpecial English for Automobile CHAPTER INTERNAL COMBUSTION ENGINE Main parts of liquid cooling system: radiator 散热器散热器 fan 风扇风扇 Coolant recovery system 冷却液循环系统冷却液循环系统 Coolant pump 冷却液（水）泵冷却液（水）泵 Water jacket 水套水套 thermostat 节温器节温器 SEASpecial English for Automobile CHAPTER INTERNAL COMBUSTION ENGINE Operation of thermostat Operation of thermostat Little circulation （小循环）（小循环） Full circulation （大循环）（大循环） SEASpecial English for Automobile CHAPTER INTERNAL COMBUSTION ENGINE 1) Thermostat circulation: When the engine is cool, the thermostat remains closed so that coolant cannot circulate through the radiator. Instead, coolant is recirculated within the engine block and cylinder head until the coolant reaches a predetermined temperature. At that temperature, a wax-like pellet expands inside the thermostat to open it and allow the coolant to flow. Fig. 2-34. Today, most original-equipment thermostats open at approximately 85C to 90C. In hotter climates, a “cooler” thermostat may be used to help avoid overheating. 当发动机温度较低时，节温器保持关闭，冷却水不能流通散热 器进行循环，而是在发动机缸体和缸盖之间循环流动，一直到 冷却水达到预定的温度为止。在该温度下，节温器中的蜡芯膨 胀，从而打开节温器，使得循环水流经节温器。目前，多数原 装节温器的开启温度大约在8590 当发动机温度较低时，节温器保持关闭，冷却水不能流通散热 器进行循环，而是在发动机缸体和缸盖之间循环流动，一直到 冷却水达到预定的温度为止。在该温度下，节温器中的蜡芯膨 胀，从而打开节温器，使得循环水流经节温器。目前，多数原 装节温器的开启温度大约在8590C。气温较高时，可采用低 温节温器防止发动机过热。 C。气温较高时，可采用低 温节温器防止发动机过热。 SEASpecial English for Automobile CHAPTER INTERNAL COMBUSTION ENGINE 2) anti-freeze: This is a solution which is added to the cooling system to lower the temperature at which freezing of the coolant occurs: the actual freezing temperature is governed by the quantity of anti-freeze added to the system. Ice increases its volume as its temperature decreases, so extensive damage to the cylinder block will result if the coolant freezes. Most modern anti-freeze solutions contain special chemical additives called inhibitors to reduce corrosion of the metal parts. Care must be taken to avoid splashing anti-freeze on the vehicle paintwork, since some of the chemicals can soften the paint. 防冻剂溶液添加到冷却系统中，可降低冷却水冷冻的温度。冷却 水实际的冷冻温度是由添加的防冻剂的数量来控制的。温度降低 时，冰的体积会增加，所以冷却水一旦冷冻会给发动机缸体带来 极大的损害。现在多数的防冻剂都含有特殊的化学添加剂（称为 抑制剂）用于减小对金属部件的腐蚀。由于有些化学剂会软化油 漆，因此一定要避免把防冻剂溅到汽车的漆面上。 防冻剂溶液添加到冷却系统中，可降低冷却水冷冻的温度。冷却 水实际的冷冻温度是由添加的防冻剂的数量来控制的。温度降低 时，冰的体积会增加，所以冷却水一旦冷冻会给发动机缸体带来 极大的损害。现在多数的防冻剂都含有特殊的化学添加剂（称为 抑制剂）用于减小对金属部件的腐蚀。由于有些化学剂会软化油 漆，因此一定要避免把防冻剂溅到汽车的漆面上。 SEASpecial English for Automobile CHAPTER INTERNAL COMBUSTION ENGINE Review 2: Whats the function of the lubrication system? Review 2: Whats the function of the lubrication system? Lubricating Cleaning Cooling Sealing Oil pump filtergauze screen filter Oil pan main oil gallery SEASpecial English for Automobile CHAPTER INTERNAL COMBUSTION ENGINE 3) The purpose of the lubrication system is to circulate oil through the engine. An engine must have a good lubrication system. Without it, the friction heat from the contact of the moving parts would wear the parts and cause power loss. Oil, when placed between two moving parts, separates them with a film. This oil film prevents the parts from rubbing against each other. This oil film also cushions the parts, giving quieter and smoother engine operation. 润滑系统的作用是使机油在发动机里循环流动。发动 机必须要有良好的润滑系统，不然移动部件相互接触 摩擦而产生的热量会损害发动机部件，并损失发动机 功率。机油位于两个移动部件之间，通过油膜隔开两 部件。油膜防止部件之间的相互摩擦，它垫在两个不 部件之间，使得发动机工作安静、平稳可靠。 润滑系统的作用是使机油在发动机里循环流动。发动 机必须要有良好的润滑系统，不然移动部件相互接触 摩擦而产生的热量会损害发动机部件，并损失发动机 功率。机油位于两个移动部件之间，通过油膜隔开两 部件。油膜防止部件之间的相互摩擦，它垫在两个不 部件之间，使得发动机工作安静、平稳可靠。 SEASpecial English for Automobile CHAPTER INTERNAL COMBUSTION ENGINE Types of friction Types of friction Dry frictionBoundary frictionLiquid friction SEASpecial English for Automobile CHAPTER INTERNAL COMBUSTION ENGINE Types of lubrication Types of lubrication Splash lubrication （飞溅润滑）（飞溅润滑） Pressure lubrication （压力润滑）（压力润滑） Grease lubrication （润滑脂润滑）（润滑脂润滑） SEASpecial English for Automobile CHAPTER INTERNAL COMBUSTION ENGINE 4) In most cars, the oil pump is in the crankcase above the sump. It draws oil through a tube that extends downward into the sump. This tube has a filter screen over its bottom end. The screen keeps large pieces of sludge and dirt from being drawn into the pump. The tube may be hinged on the pump end so that it can move up and down as the oil level changes in the sump. Thus, the pump always draws oil from the top of the sump, not from the bottom where the dirt and sludge tend to settle. Modern cars use one of two common types of oil pumps - the gear-type and the rotor-type. 在多数汽车上，机油泵位于油底壳上方的曲轴箱里。机油泵通 过向下延伸到油底壳里的一根油管吸油，该油管底端有滤网， 可防止大块的沉淀物和污垢吸入机油泵。油管铰接在机油泵的 末端，这样在油底壳里的油面变化时油管可上下移动