• System for mixing fuel with air in an engine.
• Primary fuel delivery system used in automotive petrol engines.
• Almost completely replaced carburettors in the late 1980s.
• With the advent of electronic fuel injection (EFI), the diesel and gasoline hardware has become similar.
• EFI’s programmable firmware has permitted common hardware to be used with different fuels.

• Draws fuel from the car’s fuel tank.
• Has check valves located at its inlet and outlet ports.
• Check valves force the fuel to flow in one direction only.
• Supplies fuel injector with this pressurised fuel by sending the fuel through the fuel filter to a fuel rail.
• This fuel rail is directly connected to the fuel injectors.
• Any excess fuel which is not used by the fuel injectors goes back to the fuel tank through a return line.

• While the engine typically operates between 600 to about 7000 rpm (revolutions per minute), the wheels only rotate between 0 to 1800 rpm.
• The engine provides its maximum torque output in the middle of its range (more or less) while the highest amount of torque is often required for pull away.
• Some kind of transformation needs to take place for engine power to be transmitted to the wheels. The gearbox transmission is responsible for this.

• The most common problem that occurs with the clutch is that the friction material on the clutch plate wears out and thus causes the clutch to start slipping.
• This wearing only occurs when the clutch plate and flywheel are spinning at different speeds.
• Once they are locked together and spinning at the same speed, no wear occurs.
• In the most extreme case, the clutch will cease to draw any power from the engine to the wheels and will need to be replaced.

• The compressor runs with a belt in line with the crank shaft pully of the engine and pumps refrigerant vapour under high pressure to the condenser when the air conditioning system is turned on.
• The liquid refrigerant then moves to a reservoir-like vessel, called the receiver-dryer, which removes any moisture that may have leaked into the refrigerant (moisture can cause ice crystals which create blockages in the system).

• The pressurized refrigerant is then moved to the expansion valve
• Expansion valve removes the pressure from the liquid refrigerant so that it can expand and become refrigerant vapour in the evaporator.
• The evaporator is located inside the passenger compartment, just above the footwell.
• As the cold, low-pressure refrigerant is passed into the evaporator, it absorbs and vaporizes heat from the passenger compartment (a blower fan that blows air from the passenger department over the evaporator so that cold air is circulated inside the car).

Suspension

System of shock absorbers, springs and linkages that connects a vehicle to its wheels.

• Contributes to the safe handling and braking of a car
• Also creates a comfortable ride for the occupants and isolating them from road noise and vibration.
• Important for the suspension to keep the wheels in contact with the road as much as possible, otherwise, the traction of the car will not be sufficient to ensure safe handling.

• Allow the wheels of a vehicle to rotate easily and support the weight of the vehicle.
• Always need to be in good condition and free of leaks (to keep the lubricant inside and contaminants out).

A big challenge in the design of a motor vehicle’s power transmission system:

• The engine’s power does not simply get transmitted to the wheels in a straight line.
• The drive shaft needs to transmit power at an angle to reach the wheels.

The CV joints allow this to happen by transmitting power at a constant rotational speed through an angle without any noticeable increase in friction.

Brake Pads

• Components of braking systems using brake discs.
• Steel backing plates with friction material bound to the surface.
• They make contact with the brake disc to stop wheel rotation.
• Should be replaced regularly.
• Usually equipped with a thin piece of soft metal that causes the brakes to squeal when the pads are too thin.

Brake Lining

• Part that makes contact with the brake disc or drum.
• Composed of soft but extremely tough and heat-resistant material.
• Attached to the brake pad or brake shoe (usually using high-temperature adhesives or rivets).

Brake Drums

• Part of the brake system that stops the car.
• Usually made of solid cast iron and can be ventilated (depending on vehicle weight and power).
• The action of stopping is caused by the friction of the brake pads pressing down hard on the brake discs.
• Brake drums are subjected to very extreme temperatures and conditions.
• Over time, the discs can become worn and develop hotspots which will cause the wheels to wobble (vibration in the steering wheel).

Brake Drum Skimming

Skimming the discs so that they perfectly match the drive flange again will eliminate issues and prevent the need for replacement.
Skimming is necessary when:

• Drums are corroded or rusty
• There is brake shudder
• Brakes feel spongy

Brake Shoes

• Components of braking systems using brake drums.
• Carry the brake lining which is riveted or glued to the shoe.
• When the brakes are applied, the shoe moves and presses the lining against the inside of the brake drum, stopping wheel rotation.

Brake Fluid

• Type of hydraulic fluid that turns force into pressure.
• Must have a very high boiling point to avoid vaporization.
• During braking, the brake fluid is subjected to very high temperatures.

As the driver applies the brakes, the fluid is forced into cylinders at each car wheel by the master cylinder, moving a pair of pistons outwards to thrust the brake shoes against the brake drums.

Brake Fluid Flush

• The problem with brake fluid is that it is hygroscopic.
• This means that it is inclined to absorb water very easily (even from the air).
• When this happens, the boiling point of the fluid decreases and braking performance is compromised.
• Also, the more water the brake fluid absorbs, the more corrosive it becomes, and it will eventually cause damage to other parts of the brake system.
• This is why your brake fluid needs to be flushed out and replaced.

Starter Motor

A starter motor is a very powerful DC electric motor with a solenoid attached to it.

• Connected to car battery to acquire a high enough current to start engine.
• The solenoid acts as a switch or connection between the battery and the starter motor.

Alternator

Charges the battery and powers the electrical system of the vehicle while the engine is running.

Generates electricity in the same way that a DC generator does:

• Magnetic field around the conductor changes.
• Current is created in the conductor.

Carburettor

Blends the air and fuel which enters the engine.

• Air passes into inlet manifold through open pipe.
• Fuel passes through small holes in pipe.
• Flow of fuel controlled by calibrated jets.
• Calibrated jets affected by accelerator pedal.

.Cooling System

Petrol engines are not very efficient in converting chemical energy into mechanical power. A vehicle’s engine needs a cooling system to control this.

An engine runs at its best when the coolant is about 93 degrees Celsius.

• The engine is hot enough to allow the oil to flow freely.
• To allow the fuel to vaporize easily and
• To minimize metal wear.
• It is also not too hot to cause engine burnout.

Cooling System Flush

Over time, the coolant and antifreeze chemicals in an engine (used to prevent the engine from overheating) deteriorate under usage.

• This causes them to lose their resistance to freezing and boiling.
• This, along with other components corroding, can cause the system to become clogged over time.
• In extreme cases, a cooling system blockage can occur.
• To prevent this, a cooling system flush is recommended – it flushes all the old chemicals out of your car’s engine and cleans it of any particles that have built up due to corrosion.

Water Pump

Driven by the cambelt or the v-belt and circulates water whenever the engine is running.

• The water is continuously drawn from the centre of the pump (which is where the inlet is)
• Pump vanes fling the water outside the pump, where it can then enter the engine.
• After flowing through the engine, the water is transmitted to the radiator and finally back to the input of the water pump.

Spark Plug and Glow Plug

• The spark plug fits into the cylinder head of an engine.
• Ignites the compressed petrol using an electric spark when the car is started.

A diesel car does not use a spark plug. It uses a glow plug to raise the temperature of the air to a point where the diesel fuel combusts spontaneously.

Oil Pump

Whether your engine is idling or performing at its full capacity, it contains a host of moving metal parts that would, was it not for some form of lubrication, violently overheat.

An oil pump:

• Directs oil to all the metal-contacting surfaces in the engine.
• Uses a high-pressure system to draw oil from the oil pan and submit it through several passages in the engine to specific parts.

Crank Shaft / Camshaft / Chain kit

• Rotated by the timing/cam belt.
• Connected to the pistons of an engine through crankpins which allow its rotation to be translated into the linear piston motion.
• Opens the valves which control the air/fuel intake and exhaust of the engine.
• The relationship between the camshaft and crankshaft rotations is important.
• The valves need to be opened at the appropriate time during the piston stroke.

The timing belt is responsible for this vital synchronization

Cambelt

Also known as the timing belt.

Typically made of rubber and high-tensile fibres (made of fibreglass or Kevlar) which act to withhold tension.

• Controls the timing of the engine valves.
• Cambelts replaced the older style timing chains.
• Certain car manufacturers have reverted to timing chains due to their durability.
• Connects the crankshaft to the camshaft.
• The crankshaft controls the pistons of the engine
• The camshaft controls the opening and closing of the engine’s valves.

The cambelt must be replaced at the car manufacturer’s scheduled time/distance intervals; otherwise, a complete breakdown or engine failure could occur (which would cost much more to repair than a timing belt replacement).