Vehicle Systems And Maintenance Page 2
The Engine Cooling System
Moving Parts of an
engine, and the explosion that happens in the piston chambers, create high temperatures. The coolant (antifreeze)
mixture (with water) has to be cooled off. This happens in the cooling system.
- The Coolant
is one of several substances, a common one is ethylene glycol, that are mixed with water and circulated thru the
car's cooling system. This mixture absorbs some of the heat created by the engine. The coolant also keeps the engine from freezing, and provides
lubrication for the cooling system.
- The radiator
is a heat exchanger connected to the engine by an upper and lower hose. When the coolant mixture travels through the radiator it
transfers heat from the coolant to the atmosphere before the
coolant is returned to the engine. A thermostat regulates the
volume of coolant flow in order to keep the engine at optimum
Vehicle Electrical System
- The battery
is the only source of electricity in your car. When you turn the ignition switch to start your car, electricity is sent to the
motor and to the spark plugs. Once your car is started the alternator keeps everything working.
It also recharges the
battery at the same time. The voltage regulator controls the
amount of electricity that is being generated. The coil and the distributor generate and deliver the very high voltage needed
by the spark plugs. The electricity is
delivered through the car by electrical circuits for lighting, small electrical motors in your car, to operate computers that control certain functions,
radio. Your car has fuses. These minimize the chance of fires by disconnecting circuits that may
be drawing too much current.
The Steering Assembly
- The steering assembly is the group of mechanisms that allow the
driver to guide and direct a car. These include the steering wheel, steering column, steering box, linkages, and wheel support.
- The steering
wheel is used by the driver to direct the vehicle. Steering
linkage converts the motion of the drivers hands into movements of
- The steering
column is a metal shaft that connects the steering wheel to
the steering box.
- The steering
box is a gearbox that is located at the lower end of the
steering shaft. It converts the rotary motion of the steering wheel
into the straight-line motion of the steering arms and steering
- The steering
linkage are rods that carry movement to
the steering knuckle. The steering knuckle is
the part that is attached to the upper and lower control arms, or the
kingpin, which allows the front wheels to pivot.
- The power steering system makes turning
the steering wheel much easier. It activates a hydraulic system which amplifies the force you exert on the steering wheel. In order for the system to work the engine must
The Suspension System
- A car's suspension system connects the wheels to the body and engine. Without the suspension system you would feel every stone
on the road while driving. The suspension system reduces vibration.
- The shock
absorber is a friction device that controls and damps
spring oscillations. Thus "shock absorbers" isn't accurate. Springs
actually absorb road shock. Shock absorbers convert the energy of the springs into heat (by friction). Because shocks affect
up-and-down wheel motion they are an important element of your car's riding and handling abilities.
- The springs,
leaf or coil, absorb the up and down
motion of the car. The shocks keep the springs from continuing to
bounce up and down. The strength of the springs determine the size of the load your car or
truck will carry.
- The linkage is a series of rods and levelers used to transmit motion from one
component to the other.
The Braking System
- Your vehicle has two braking systems. Both work independently of the other. The main
system is operated by your brake pedal and is used to slow down and stop your vehicle while
you are driving . The parking brake, also known as the
emergency brake is used to park on a
downhill or uphill grade. It can also be used to stop your vehicle
in case of emergency, but it is mainly used to stop your vehicle
from rolling out of a parked position.
- When you press your brake pedal, a
piston in your master
cylinder forces brake fluid through
hydraulic lines to pistons in the wheel cylinders,
where additional pistons provide the force to apply your brakes.
Hydraulic fluid is stored in a brake fluid reservoir normally
located in the engine compartment.
- There are two types of brakes,
drum brakes and disc brakes. Drum brakes slow your
vehicle by using the friction of the brake shoe pushing against the inside
of the drum, which is rotating with the wheel. Disc brakes slow your
car by using the friction of a caliper pressing against a disc, which is
rotating with the wheel. Both drum and disc brakes convert friction
force to heat. If the brakes get too hot they cease to work
because they can not dissipate enough heat.
Brakes will only slow
your car while there is friction between the moving parts of the
brakes. If the wheels lock, as is the case of a skid, the drums or
discs are not moving and there will be no friction. The anti lock brake system is the system
that keeps the brakes from becoming locked, by first sensing if they
are locked, and then automatically, rapidly releasing and applying
pressure. If you do not have ABS you
can avoid having your brakes lock by rapidly applying and releasing pressure to the
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