Charging System

  An charging system reenergizes the battery and supplies electricity for all the car'selectrical system. It performs several functions：

    ．Recharges the battery after engine cranking or after the use of electrical accessories with the engine shut off

    ．Supplies all the vehicle's electricity when the engine is running Provides a voltage output that is slightly higher than battery voltage

    ．Changes output to meet different electrical loads Fig. 5. 2 shows the major parts of typical charging system:

    ．Alternator一generator that uses mechanical power to produce electricity

    ．Voltage regulator一electronic device that controls the output voltage and current of the alternator. The engine control module may serve as the voltage regulator

    ．Alternator drive belt一links the engine crankshaft pulley with the alternator pulley to drive the alternator

    ．Charge indicator一ammeter，voltmeter, or warning light that informs the driver of the barging system condition

    ．Charging system harness一wiring that connects the parts of the system

    ．Battery一provides current to initially energize the alternator and helps to stabilize alternator output

    During the engine cranking, the battery supplies all he electricity used by the automobile. Then, when the engine starts running, the charging system takes over to provide current to the vehicle's electrical systems. The voltage regulator keeps alternator output at a preset charging voltage (13-15 volts)．Since this is higher than battery voltage（12. 6 volts)，current flows back into the battery and recharges it. Current also flows to the ignition system，electronic fuel injection system, on-board computer, radio，or any other device using electricity.