automotive starting system

UNIVERSITY OF RIZAL SYSTEM

CAINTA CAMPUSTLE - AUTOMOTIVE

THE STARTING SYSTEM

The starting system includes the battery, starter

motor, solenoid, ignition switch, and in some cases, a starter relay.

An inhibitor (neutral safety) switch is included in the starting system circuit to prevent the vehicle from being started while in gear.

BATTERY An electrochemical device for

storing energy in chemical form so that it can be released as electricity for cranking the engine and powering the electrical load. Also a group of electric cels connected together.

STARTING MOTOR A small, powerful electric motor

that converts electrical energy from the battery into mechanical energy to spin the crankshaft and start the engine.

Starter motorA starter is an electric motor that turns over

or "cranks" the engine to start it.A starter consists of the very powerful DC electric motor and the starter solenoid that is usually attached to the motor

Inside, a typical starter motor has the electric windings (coils) attached to the starter motor housing and the armature (the rotating part) that is connected through the carbon brushes in series with the windings.

On the front end of the armature, there is a small gear that attached to the armature through an overrunning clutch. This part is commonly known as the Bendix.

SOLENOID

An electromechanical device which, when connected to an electrical source such as a battery, produces a mechanical movement.

The starter solenoid works as a powerful electric relay - when activated, it closes the electric circuit and sends the battery power to the starter motor.

At the same, the starter solenoid pushes the starter gear forward to mesh with the engine flywheel.

A typical starter solenoid has one small connector for the control wire and two large terminals: one for the positive battery cable and the other for the starter motor.

IGNITION SWITCH

The key-operated main power switch that opens and closes the circuit that

supplies current to the ignition and other electrical systems.

INHIBITOR (NEUTRAL SAFETY)

*NEUTRAL-START SWITCH A switch wired into the ignition switch to prevent engine cranking unless the transmission shift lever is in NEUTRAL.

STARTER RELAY

*RELAY = An electrical device that opens or

closes a circuit in response to a voltage signal.

Battery cablesA starter motor

requires a very high current to crank the engine, that's why it's connected to the battery with thick (large gauge) cables.The negative (ground) cable connects the "-" battery terminal to the engine cylinder block close to the starter.

The positive cable connects the "+" battery

terminal to the starter .solenoid.

To start the automobile engine, the crankshaft must turn fast enough for air-fuel mixture to enter the cylinders.

An electric starter or starting motor does this job.

It converts electrical energy from the battery into mechanical energy that rotates the crankshaft.

The starting system has 2 separated but related circuits

1. Low-current control circuit 2. High-current motor circuitboth operate on battery voltage.

1. Low-current control circuit (thin arrows)

2. High-current motor circuit (thick arrows)

both operate on battery voltage.

*When the driver turns the ignition key to START, the CONTROL CIRCUIT causes heavy contacts to close in a starter relay or solenoid switch.

*High current then flows from the battery insulated Cable through these contacts to the starting motor.

A gear on the starting motor shaft moves into mesh with the ring gear around the engine flywheel or drive plate.

As the starting-motor shaft turns, it spins the crankshaft fast enough to start the engine.

STARTING-SYSTEM TROUBLE DIAGNOSIS

3 BASIC STARTING SYSTEM TROUBLES 1.) The engine does not crank.

2.) The engine cranks slowly but does not start.

3.) The engine cranks normally but does not start.

(not caused by starting sys.) *problem “fuel or ignition sys./engine” OTHER COMPLAINTS

Relay/solenoid-chattering Slow disengagement of the pinion from

the ring gear.