汽车专业英语U1L 4(发动机部分)

1、陈长梅陈长梅one. the ignition systema gasoline engine uses an electrical spark to ignite the mixture. generating this spark is the role of the ignition system. conventional ignition systems consist of battery, ignition coil, distributor, ignition switch, spark plugs, etc （fig.4-1）.ignition system (点火系统点火系

2、统)点火点火开关开关点火点火线圈线圈火花塞火花塞分电器分电器高压线高压线蓄电池蓄电池组组成成ignition systemthere are many different kinds of ignition systems. most of these systems can be placed into three types：the conventional breaker point ignition system （since the early 1900s）; the electronic ignition system （eis） （popular since the mid 19

3、70s）; and the distributorless ignition system （dis） （introduced in the mid 1980s（fig.4-2）. today, most ignition systems are distributorless ignition systems.点火线圈ignition coilignition coil1the ignition coilthe ignition coil is a transformer designed to set up primary voltage of 12v to approximately 2

4、0,000v required to jump spark during the spark plug gap in the combustion chamber. it is composed of a primary winding, secondary winding and core of soft iron.2the ignition switchthe purpose of the ignition switch is to connect and disconnect the ignition system from the battery, so the engine can

5、be started and stopped as will.n火花塞nspark plugspark plug3the spark plugthe spark plug provides the gap across which the high tension voltage jumps, to create the spark and ignites the compressed air-fuel mixture.4the ignition timingthe ignition system must be timed accurately. incorrect timing resul

6、ts in the loss of efficiency and power, even not fire.分电器分电器distributordistributorn高压线（分缸高压线）高压线（分缸高压线）nhigh voltage wirenvoltage 电压；电压；nwire 电线；电线；disconnector fusetwo. the starting systemthe starting system provides the power to turn the engine over until it can operate under its own power. the ty

7、pical starting system has four components：battery, starting switch （ignition key）, starter solenoid switch and starting motor （fig.4-3）. starting starting systemsystem组组成成组组成成起动机起动机蓄电池蓄电池点火开关点火开关transmissionsolenoids l n d direct-current motor 起动机起动机：starterstarter1the starting switchthe starting sw

8、itch is part of the ignition key. the ignition key usually has four positions：off, accessories, on （run） and start.2the starter solenoid switchthe starter solenoid switch is an electromagnetically operated heavy-duty switch that can have two distinct functions. first, the solenoid switch opens and closes the circuit between the battery and cranking motor. second, many solenoids also shift the cranking pinion to mesh with the ring gear of the flywheel.3the starting motorthe starting or cranking motor itself is nothing but a device th