新编汽车专业英语第3版黄汽驰电子课件Unit3PassageB.pptxVIP

Unit Three　 Engine Systems　;Passage BIgnition, Starting and Fuel Systems;Ignition system is divided into 3 types: contact-point ignition system (Fig.3-15), non-point ignition system (Fig.3-16) and non-distributor ignition system ( Fig.3-17)． First one is convention ignition system (CIS), the last two ones are electronic ignition system (EIS).; ;In non-point ignition system, a reluctor disk and an electronic control module (ECM) take the place of the contact points in the contact-point ignition system． With the development of the automotive technology, non-distributor ignition system is replacing the other two types of the ignition systems mentioned above． So we mainly introduce the non-distributor ignition system．;The major components of a non-distributor ignition system are engine control unit (ECU), ignition control unit (ICU), a set of ignition coils and some sensors such as crankshaft position sensor, camshaft position sensor and knock sensor． The spark plugs are fired directly from the coils． The spark timing is controlled by ECU and ICU according to the information received from the sensors． There are multiple coils on cars so each one serves one or two spark plugs．;If there are 3 coils that mounted together in a coil pack in a car with a 6-cylinder engine, each coil is connected to two spark plugs with spark plug wires． The coil fires bothspark plugs at the same time． One spark plug fires on the compression stroke igniting the fuel-air mixture to produce power while the other spark plug fires on the exhaust stroke and does nothing (see Fig.3-17a).;If there are 4 coils, each coil is mounted directly on the top of each spark plugas shown in 3-17b． This design completely eliminates the spark plug wires for even better reliability．;Starting system Starting system functions to crank the engine fast enough to allow the engine to start (see Fig.3-18). The starting system and ignition system must work together for good engine starting． This system includ