Car Started

Pre-engaged starter

The pinion is moved by the solenoid; there is an initial flow in which the motor turns slowly to allow engagement, so the whole operation is more gentle and causes less habiliment on the teeth.

To make an engine start it must be turned at some speed, so that it sucks fuel and air into the cylinders , and compresses it.

The powerful electric starter motor does the turning. Its shaft carries a pocket-size pinion ( gear bicycle) which engages with a big gear band around the rim of the engine flywheel .

In a front-engine layout, the starter is mounted low down nigh the back of the engine.

The starter needs a heavy electric current , which it draws through thick wires from the bombardment . No ordinary hand-operated switch could switch it on: it needs a large switch to handle the high current.

The switch has to be turned on and off very quickly to avert unsafe, damaging sparking. So a solenoid is used - an organisation where a pocket-size switch turns on an electromagnet to consummate the circuit .

The starter circuit

All the components are earthed to the metal car body. Simply one wire is needed to behave current to each component.

The starter switch is ordinarily worked by the ignition central. Turn the key beyond the 'ignition on' position to feed current to the solenoid.

The ignition switch has a render jump , so that as shortly as you release the central it springs dorsum and turns the starter switch off.

When the switch feeds current to the solenoid, the electromagnet attracts an fe rod.

The movement of the rod closes two heavy contacts, completing the excursion from the battery to the starter.

The rod also has a return spring -when the ignition switch stops feeding current to the solenoid, the contacts open up and the starter motor stops.

The return springs are needed considering the starter motor must non turn more information technology has to in order to start the engine. The reason is partly that the starter uses a lot of electricity, which quickly runs down the battery.

Also, if the engine starts and the starter motor stays engaged, the engine will spin the starter so fast that it may exist badly damaged.

The starter motor itself has a device, chosen a Bendix gear, which engages its pinion with the gear ring on the flywheel just while the starter is turning the engine. Information technology disengages as soon as the engine picks up speed, and in that location are two means past which information technology does and so - the inertia system and the pre-engaged system.

The inertia starter relies on the inertia of the pinion - that is, its reluctance to begin to turn.

Inertia organisation

An inertia type starter: this one is an 'inboard' type in which the Bendix gear throws the pinion towards the motor; there are also 'outboard' ones in which it moves the other way.

The pinion is not fixed rigidly to the motor shaft - information technology is threaded on to it, similar a freely turning nut on a very coarse-thread bolt.

Imagine that you suddenly spin the bolt: the inertia of the nut keeps it from turning at one time, so it shifts along the thread of the bolt.

When an inertia starter spins, the pinion moves forth the thread of the motor shaft and engages with the flywheel gear ring.

It then reaches a stop at the cease of the thread, begins to turn with the shaft so turns the engine.

The inertia of the heavy piston associates prevents it from spinning immediately when the motor shaft turns, so information technology slides forth the thread and into engagement; when the engine starts, the pinion is turned faster than its shaft, so it is thrown back out of appointment.

In one case the engine starts, it spins the pinion faster than its ain starter-motor shaft. The spinning action screws the pinion dorsum down its thread and out of engagement.

The pinion returns so violently that in that location has to be a strong spring on the shaft to cushion its impact.

The violent engagement and disengagement of an inertia starter can cause heavy wear on the gear teeth. To overcome that problem the pre-engaged starter was introduced, which has a solenoid mounted on the motor.

There's more to a machine starter organisation: As well equally switching on the motor, the solenoid also slides the pinion along the shaft to engage it.

The shaft has directly splines rather than a Bendix thread, so that the pinion e'er turns with it.

The pinion is brought into contact with the toothed ring on the flywheel by a sliding fork. The fork is moved by a solenoid, which has two sets of contacts that close one subsequently the other.

The first contact supplies a low current to the motor so that information technology turns slowly - just far enough to allow the pinion teeth engage. Then the second contacts close, feeding the motor a high current to turn the engine.

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Source: https://www.howacarworks.com/basics/how-the-starting-system-works

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