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starting system and starter motor of the vehicle


Starting System of vehicle and starter motor


Requirements of Starting System
        An internal combustion engine requires the following criteria in order to start and continue running.
         Combustible mixture.
         Compression stroke.
         A form of ignition.
         The minimum starting speed (about 100 rev/min).
        Long service life and maintenance free.
         Continuous readiness to operate.
         Robust, such as to withstand starting forces,
        Vibration, corrosion and temperature cycles.
         Lowest possible size and weight
        In order to produce the first three of requirements, the minimum starting speed must be achieved. This is where the electric starter comes in.
The ability to reach this minimum speed is again dependent on a number of factors.
         Rated voltage of the starting system.
         Lowest possible temperature at which it must still be possible to start the engine. This is known as the starting limit temperature.
         Engine cranking resistance. In other words the torque required to crank the engine at its starting limit temperature (including the initial stalled torque).
         Battery characteristics.
         Voltage drop between the battery and the starter.
         Starter-to-ring gear ratio.
         Characteristics of the starter.
         Minimum cranking speed of the engine at the starting limit temperature.

TYPES OF STARTER MOTOR
        Inertia Starter
        Pre-Engaged Starter
        Permanent Magnet Starter
        Heavy Vehicle Starter
        Integrated Starter
        Reduction Gear Starter

Inertia Starter Motor



Bendix Drive ( Inertia Drive)


Working Principle of Bendix Drive:
        With the Bendix self-engaging pinion drive, the armature shaft spins and the drive pinion stands still while the threaded sleeve spins inside the pinion. As the sleeve spins, the pinion slides out and meshes with the ring gear. As soon as the pinion reaches its stop, the turning sleeve causes the pinion to turn with it to crank the engine.
        In detail 1, the armature shaft and pinion sleeve begin to spin. The stationary pinion is sliding to the left. In detail 2, the sliding action is stopped, and the pinion begins to turn and crank the engine. When the engine starts, detail 3, the pinion is spinning faster than the threaded pinion sleeve. This spins the pinion back out of mesh with the ring gear


Pre-Engaged Drives

        Pre-engaged starters are fitted to the majority of vehicles in use today. They provide a positive engagement with the ring gear, as full power is not applied until the pinion is fully in mesh. They prevent premature ejection as the pinion is held into mesh by the action of a solenoid.
        A one-way clutch is incorporated into the pinion to prevent the starter motor being driven by the engine.
        A Pre-engage starter motor is very similar to an inertia starter however instead of using inertia to throw the pinion out a small solenoid is used to engage the pinion before the armature turns the engine over. A primary circuit throws the pinion out, once the pinion has been thrown out power is feed to a second circuit to hold the pinion in place as the armature turns

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