发动机冷却系统外文翻译.doc

英文翻译： 原文： The Cooling System The engine cooling system actually is a temperature regulation system to protect engine from self-destruction. About one-third of the heat produced in the engine is converted into power, another third goes out through the exhaust pipe un-used, and the remaining third must be carried away by the cooling system (Some is utilized for heating the passenger compartment). To keep the engine temperature in balance is quite essential for an engine to produce power. If the engine runs too hot, it may suffer from pre-ignition since the air-fuel charge is ignited prematurely from excessive combustion chamber temperature. The viscosity of the oil is reduced. Hot oil also forms varnish and carbon deposits may be drawn into the combustion chamber where it may increase HC emissions. The behavior of the metals at excessively high tem perature also differs from that at normal temperature. Those cause poor performance and premature wear, and may even result in engine damage. If the engine runs too cold, the fuel will not vaporize properly. If the liquid fuel reaches the cylinders, it will reduce lubrication by washing the oil from the cylinder walls and diluting the engine oil. That causes a loss of performance, an increase in HC emissions, and premature wear. For these reasons, a cooling system of some kind is necessary in any internal combustion engine. There are two types of cooling systems found on motor vehicles: liquid cooled and air cooled .Air cooled engines are found on a few older cars, like the original Volkswagen Beetle, the Chevrolet Corsair and a few others. Many modern motorcycles still use air cooling, but for the most part, automobiles and trucks use liquid cooled systems and that is what this article will concentrate on. Components of a liquid cooling system include the radiator, radiator cooling fans and fan drive belt, pressure cap reserve tank, water pump, thermostat, bypass system, freeze plugs, head gaskets int