Automotive Systems and Preventative Maintenance

Copyright © 2007 by Nelson, a division of Thomson Canada Limited. 4-1Chapter 4

Prepared byMartin Restoule

Algonquin College

Automotive Automotive Systems and Systems and Preventative Preventative MaintenanceMaintenance

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ObjectivesObjectives

• Explain the major events that have influenced the development of the automobile during the past 35 years.

• Explain the difference between unitized and body-over-frame vehicles.

• Describe the manufacturing process used in a modern automobile assembly plant.

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ObjectivesObjectives

• List the basic systems that make up an automobile and name their major components and functions.

• Explain the importance of preventative maintenance.

• List at least six examples of services included in a preventative maintenance program.

Copyright © 2007 by Nelson, a division of Thomson Canada Limited. 4-4

Automotive HistoryAutomotive History

• 1896 Henry Ford test drove first gas powered Vehicle

• 1965 first exhaust emissions laws• 1977 Transport Canada begins (CAFC)

Company Average Fuel Consumption goals

Chapter 4


Types of Vehicle ConstructionTypes of Vehicle Construction

Body-Over-Frame

• The body and all major parts are bolted to the frame.

• The frame must be strong enough to maintain correct body and driveline alignment.

• Design is used on many pickups and SUVs.• Due to weight concerns (average vehicle

weight 2040 kg), most modern cars use unibody construction.

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• Body-Over-Frame Construction– A typical truck

frame with sub-frame components.



Unitized body (Unibody)• A unibody has no separate frame.• It is a stressed hull structure where each

body part provides structural support and strength to the entire vehicle.

• Tends to be more tightly structured because the major parts are all welded together.

• Is designed to transmit impact energy throughout the vehicle.

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• A Typical Unibody Design.– Typical one

piece body and frame assembly with bolt-on components.


Body ShapesBody Shapes

• Sedan– A vehicle

with front and back seats for four to six persons

– Can be either two or four door

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• Convertible– Offers the same seating as a sedan with

the ability to remove or retract the roof.

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• Sports Car– Two passenger convertibles are typically

called sports cars. – These vehicles

usually offer improved horsepower and handling.

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• Liftback or hatchback– Features a rear luggage compartment that

is an extension of the passenger area. – An upwards

opening hatch- type door allows access to the luggage compartment.

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• Station wagon– A station wagon has a roof that extends

straight back allowing for a spacious interior luggage compartment.

– Can be a two or four door model with seating for up to nine passengers.

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• Pickup– Offers a separate passenger cab for up to five

passengers (2 or 4 door and extended cab). – Has an open

cargo box.– Available in

two and four wheel drive models.

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• Van– The van body design has a tall roof and an

enclosed large cargo or passenger area.– Can seat

from 2 to 12 passengers.

– Available in mini and full- size models.

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• Sport utility vehicle– An SUV can have a range of body styles.– These are multipurpose on and off road

vehicles.– Usually four-

wheel-drive.– The number of

passengers will depend on size and model.

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• Crossover Vehicles– A new trend in vehicles that are a cross

between a station wagon and an SUV.– These are usually smaller and more fuel

efficient than a regular SUV.

– These may be two, four or all- wheel- drive


Basic Engine ComponentsBasic Engine Components

• Cylinder block– The cylinder block is a large iron or

aluminum casting the houses or holds the cylinders and most of the major mechanical engine parts.

– The block also contains passageways for coolant and lubricant.

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• Cylinder head– The cylinder head mounts on the top of the

cylinder block and forms the top to the cylinders.

– The head contains the combustion chamber, valves and ports to allow the entry and exit of the air/fuel mixture.

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• Pistons, rods, and crankshaft– The piston receives

force from the burning of the air/fuel mixture in the cylinder.

– This force pushes the piston and connecting rod downward which rotates the crankshaft generating engine power.

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• Valve train– A series of

components used to open and close the intake and exhaust valves including; the camshaft, valves, followers/lifters, rocker arms and push rods.

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• Intake and exhaust manifolds– Manifolds are ductwork assemblies.– The intake manifold

delivers the air/fuel mixture to the cylinders while the exhaust manifold carries exhaust gases from the cylinders.


Engine SystemsEngine Systems

• Lubrication system– The lubrication

system provides constant lubrication to the moving parts of the engine.

– Engine oil is sent by the oil pump through an oil filter to the many engine components.

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• Cooling system– A water pump is used to circulate coolant

through the system.– The coolant is

pushed through water jackets in the block and head.

– Heat is removed from the coolant at the radiator.

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• Fuel and air system– The fuel and air system supplies the correct

amount of fuel mixed with the correct amount of air to the cylinders.

– The system also: stores fuel, cleans outside air, delivers fuel to the engine, atomizes fuel and adjusts the fuel/air ratios during operation.

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• Emission control system– Systems have been developed and added to

engines to reduce the pollutants they emit.– Some of these systems are:

positive crankcase ventilation, evaporative emission control system, exhaust gas recirculation system (EGR), catalytic converter and air injection system.

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• Exhaust system– The exhaust system

is designed to carry toxic exhaust fumes away from the passenger compartment, to quiet the exhaust pulses and burn or catalyze pollutants.

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• Ignition system– The ignition system must generate a spark to

ignite the air/fuel mixture at the correct time.– The coil transforms battery voltage into a

spike of 30 000 to 100 000 volts to ignite the mixture.

– Ignition must occur before the piston completes its compression stroke.

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• Starting and charging system– The purpose of the

starting system is to rotate or crank the engine to allow the ignition system to fire and start the engine.

– The charging system is designed to recharge and maintain the battery’s state of charge.

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• Electronic control system– This system is

comprised of many electronic and electromechanical parts.

– The system monitors engine operation and makes adjustments to make it run efficiently.


Drivetrain ComponentsDrivetrain Components

• Clutch– Used with manual

transmissions and transaxles.

– Mechanically connects the engine flywheel to the transmissions input shaft.

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• Transmission– The driver manually selects the gear in a

manual or standard transmission.– An automatic transmission does not require

a clutch and automatically shifts forward gears.

– Transmissions allow for several gear ratios for maximum engine performance.

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• Driveline– Connects the output shaft of the transmission

to the rear axle of a rear wheel drive vehicle and both front and rear axles of a four-wheel-drive vehicle.

– A hollow drive shaft with universal joints is commonly used to connect the transmission to the drive axle.

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• Final Drive Assembly– Changes the direction

of driveline rotation and provides the final gear ratio.

– Contains a differential assembly to allow each drive wheel to rotate at different speeds during cornering.

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• Drive axles– Transmit power to the wheels.– In rear wheel drive axles, solid axle shafts

are used.– Front wheel drive vehicles use axles with

constant velocity joints at each end to allow the axle to drive through angles.

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• Transaxle– Combines the

transmission and final drive assembly in one unit.

– Transaxles are used in front wheel vehicles and are available in both standard and automatic models.


Running Gear ComponentsRunning Gear Components

• Suspension system– Supports the body, frame,

engine, and drivetrain.– The suspension system

includes springs, shock absorbers, MacPherson struts, torsion bars, anti-sway bars and links, radius and strut rods and links.

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• Steering system– Allows the driver to control the direction of

the vehicle.– The steering system includes the steering

wheel, steering gear, steering shaft, and linkage.

– Rack and pinion steering gears are commonly used in passenger cars.

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• Brakes– Allow the vehicle to slow down and stop.– Brake assemblies located at each wheel

use friction to slow and stop the vehicle.– Two types of brakes

are used disc brakes and drum brakes.

– Many vehicles use a combination of both types.

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• Wheels and tires– Provide vehicle contact to the road.– Tires are made of different types of rubber

along with other materials for strength.

– Tire tread designs vary depending on their application.

– Wheels are made of metal and vary in size and design.


VIN CharactersVIN Characters

• First – Country of origin• Second – Manufacturer• Third – Vehicle type or manufacturing division• Fourth through eighth – Vehicle features• Ninth – Check digit• Tenth – Model year• Eleventh – Manufacturing plant• Twelfth through seventeenth – Production

sequence


Typical Preventative Typical Preventative Maintenance ChecksMaintenance Checks

• Engine oil– Changing the engine oil and filter is the

most recognized preventative maintenance item.

– It is critical that the engine oil be changed on a regular basis.

– Always use the correct oil rating and viscosity.

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• Cooling system– Check the coolant level in the recovery

tank and add coolant if the level is low.

– A mixture of antifreeze and water should be added.

– Inspect all components for signs of leakage and/or damage and replace any cracked or swollen hoses.

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• Drive belts– Check the condition and tension of all drive

belts on the engine.– Carefully inspect them for

cracks, oil contamination, glazing, and tears and splits.

– Replace all belts that are damaged in any way.

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• Battery– Visually inspect the

battery for damage and corrosion.

– Corrosion can be cleaned off with a mixture of baking soda and water.

– The battery should be removed and cleaned when heavily corroded.

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• Transmission fluid– Automatic transmission fluid is a special

fluid that is dyed red to prevent confusion.– The fluid level is generally checked with

the vehicle running and in park or neutral.– Manual transaxles,

transmissions and drive axles use specific lubricants.

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• Power steering fluid– The power steering fluid level is checked

with the engine off.– A dipstick is normally

part of the filler cap.– The fluid level should be

checked when warm.– Use only the

recommended fluid.continued…



• Brake fluid– The brake fluid level and condition should

be checked at every oil change interval.– Brake fluid should be

flushed every two years because it tends to absorb moisture

– Ensure the diaphragm under the cap is not damaged.

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• Windshield washer fluid– Visually check the windshield washer fluid

level and add fluid as necessary.– Do not add straight water

or summer grade fluid in spring or fall as these can freeze damaging the tank and pump and clog the washer hoses and nozzles.

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• Wiper blades– Wiper blades should be replaced when

they become dull, torn or brittle.– Failure to replace wiper blades before

they fail can result in windshield damage.

– When changing the blades also inspect the wiper arms and springs.

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• Tires– Tires should be checked for damage (nails,

cuts, bulges and weather checks) and wear (At least 1.6 mm of tread depth).

– Tire inflation pressure should be checked when refueling.

– Follow the inflation specifications on the driver’s doorjamb decal.


SummarySummary

• Dramatic changes to the automobile have occurred over the last 40 years.

• Unibodies offer better occupant protection than body-on-frame designs.

• Many systems on today’s vehicles are controlled by computers.


SummarySummary

• All automobile engines used today are classified as internal combustion.

• The cooling system maintains proper engine temperatures.

• The lubrications system distributes motor oil throughout the engine.


SummarySummary

• The fuel system is responsible for fuel storage and delivery.

• The electrical system of an automobile includes the ignition, starting, charging, and lighting systems.

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Automotive Systems and Preventative Maintenance