Chapter 30 POWERPOINT

Use the textbook to define these Technical Terms:

1. brushes

2. engine control module (ECM)

3. ignition switch

4. neutral safety switch

5. relay

6. starter solenoid

7. starting motor

Use the textbook to answer these discussion questions:

1. List and describe the purpose of major starting circuit components.

Read the chapter summary below:

Summary

■ A 12-volt starting system uses battery power and an electric motor to turn the engine crankshaft for engine starting.

■ A starting motor converts electrical energy from the battery into mechanical or rotating energy to crank the engine.

■ A commutator serves as a sliding electrical connection between the motor windings and the brushes.

■ A field winding is a stationary set of windings (insulated wire wrapped in circular shape).

■ A permanent-magnet starter uses special high-strength magnets in place of conventional field windings.

■ A starter pinion gear is a small gear on the armature shaft that engages a large ring gear on the engine flywheel.

■ A starter overrunning clutch locks the pinion gear in one direction and releases it in the other.

■ A starter solenoid is a high-current relay that makes an electrical connection between the battery and starting motor.

■ A reduction starter is sometimes used to further increase the rotating force applied to the engine flywheel.

■ A neutral safety switch prevents the engine from cranking unless the shift selector is in neutral or park.

■ A 12-volt starter relay uses a small current flow from the start switch to control a slightly larger current flow to the starter solenoid.

■ An ECM-controlled starting circuit automatically energizes and de-energizes the 12-volt starting motor as soon as the engine sensors detect fuel combustion and the resulting rapid increase in crankshaft rpms (speed sensor signal).

■ A hybrid starting system includes a motor-generator, HV power cables, hybrid control module, HV power control module, and engine control module (ECM).

■ The HV power control module converts dc into three-phase ac for the motor-generator. If a vehicle does not have a separate hybrid control module, the HV power control module determines when the engine should be started and sends three-phase ac to operate the motor-generator for engine startup.