trigger the ignition coil. When triggered, the ignition coil
produces a high voltage output to “fire” the spark plugs.
When the ignition key is turned off, the coil stops func-
tioning and the spark-ignition engine stops running.
Starting System
The starting system has a powerful electric starting
motor that rotates the engine crankshaft until the engine
“fires” and runs on its own power. The major parts of the
starting system are shown in Figure 1-14A.
A battery provides the electricity for the starting
system. When the key is turned to the start position, cur-
rent flows through the starting system circuit. The starting
motor is energized, and the starting motor pinion gear
engages a gear on the engine flywheel. This spins the
crankshaft. As soon as the engine starts, the driver must
shut off the starting system by releasing the ignition key.
Charging System
The charging system is needed to replace electrical
energy drawn from the battery during starting system
operation. To re-energize the battery, the charging system
forces electric current back into the battery. The fun-
damental parts of the charging system are shown in
Figure 1-14B. Study them!
When the engine is running, a drive belt spins the
alternator pulley. The alternator (generator) can then
produce electricity to recharge the battery and operate
other electrical needs of the vehicle. A voltage regulator,
usually built into the alternator, controls the voltage and
current output of the alternator.
Lighting System
The lighting system consists of the components that
operate a vehicle’s interior and exterior lights (fuses,
wires, switches, relays, etc.). The exact circuit and part
configurations will vary from one model to another.
The exterior lights typically include the headlights,
turn signals, brake lights, parking lights, backup lights,
and side marker lights. The interior lights include the
dome light, trunk light, instrument panel lights, and other
courtesy lights.
Cooling and Lubrication Systems
The cooling and lubrication systems are designed to
prevent engine damage and wear. They are important sys-
tems that prevent the engine from self-destructing.
The cooling system maintains a constant engine
operating temperature. It removes excess combustion
heat to prevent engine damage and also speeds engine
warm-up. Look at Figure 1-15.
The water pump forces coolant (water and antifreeze
solution) through the inside of the engine, hoses, and
12 Section 1 Introduction to Automotive Technology
Figure 1-14. Note the basic actions and components of the starting and charging systems.
Starting system Charging system
Small current
activates starter
Ignition
switch
Flywheel
gear
Starting
motor
High current
flow to starter
Battery A Battery B
Current flows through
and recharges battery
Ignition
switch
Voltage to
activate regulator
Voltage
regulator
Alternator
Drive
belt