Starting System

     The starting system has helped make the modern automobile a reliable and convenient means of transportation. It provides an easy method of starting the engine.

    The starting system uses battery power and an electric motor to turn the engine crankshaft for engine starting. The purpose of the battery is to supply current to the starter motor, to provide current to the ignition system while cranking, to supply additional current when the demand is higher than the alternator can supply and to act as an electrical reservoir. Fig. 5. 1 shows the basic parts and action of a starting system.

    When you turn the ignition key to start the engine，current flows through the solenoid coil. This closes the solenoid contacts，connecting battery current directly to the starting motor, or starter. When the starting motor circuit is electrically energized，the starter pinion gear is pushed into and meshes with the flywheel ring gear. The motor-driven pinion gear turns the flywheel ring gear until the engine starts and runs on its own power.

    When the engine starts, you release the ignition key. This breaks the current flow to the solenoid and starter. The starter stops turning, and the starter gear moves away from the flywheel gear.