It is utmost important to know the basic functions of your car to keep it maintained for its long life.  We here try to explain you the same for your easy understanding :

Main parts of a car engine

CAR engine/mechanics


Link for video - How a car engine works

Car engines are built around a set of "cooking pots" called cylinders (usually anything from two to twelve of them, but typically four, six, or eight) inside which the fuel burns. The cylinders are made of super-strong metal and sealed shut, but at one end they open and close like bicycle pumps: they have tight-fitting pistons (plungers) that can slide up and down inside them. At the top of each cylinder, there are two valves (essentially "gates" letting things in or out that can be opened and closed very quickly). The inlet valve allows fuel and air to enter the cylinder from a carburetor or electronic fuel-injector; the outlet valve lets the exhaust gases escape. At the top of the cylinder, there is also a sparking plug (or spark plug), an electrically controlled device that makes a spark to set fire to the fuel. At the bottom of the cylinder, the piston is attached to a constantly turning axle called a crankshaft. The crankshaft powers the car's gearbox which, in turn, drives the wheels.


How Cars Work

The process by which a car works is a lot simpler than you may think. When a driver turns a key in the ignition:

The car battery powers up sending power to the starter motor, which Turns the crankshaft, which hets the pistons moving with the pistons moving the engine fires up and ticks over a fan draws air into the engine via an air filter.  The air filter removes dirt and grit from the air. The cleaned air is drawn into a chamber where fuel (petrol or diesel) is added.  This fuel-air mix (a vaporised gas) is stored in the chamber. When the driver presses the accelerator pedal, the throttle valve is opened.  The gas-air mix passes through an intake manifold and is distributed, through intake valves, into the cylinders. The camshaft controls the opening and closing of the valves. The distributor makes the spark plugs spark, which ignites the fuel-air mix. The resulting explosion forces a piston to move down which in turn causes the crankshaft to rotate.

What happens in the cylinders is the magic that gives power and motion to the car wheels. Most car engines use a four-stroke combustion cycle. This cycle starts with piston at the top of the cylinder.


Intake stroke: intake valve opens and the piston moves down allowing the fuel-air mix to enter the open space.

Compression stroke: the piston moves upwards. This compresses the fuel-air mix by forcing it into a smaller space. Compression makes the fuel-air mix explode with greater force.

Power cycle: spark from a spark plug ignites the fuel-air mix. The explosion forces the piston down the cylinder.

Exhaust cycle: the exhaust valve opens and the piston moves back to the top of the cylinder which forces the exhaust fumes out.

The bottom of each piston is attached to the crankshaft.

As the pistons are forced up and down they rotate the crankshaft, which after sending the power through the transmission, turns wheels.

Most cars have at least four cylinders. More powerful cars have more. For example a V6 has six cylinders and a V8 has eight.

The harder a driver presses on the accelerator pedal the more fuel-air mix is passed into the cylinders and the more power is produced.

What Are Revolutions Per Minute?

The four-stroke cycle repeats itself thousands of times a minute. These repetitions are more commonly known as Revs.

A rev counter tells you how many thousand times per minute the cycle is repeated.




The Transmission

Controls the power contained in the crankshaft before it goes to the wheels and allows a driver to control the speed/power of a car by providing different speed/power ratios known as gears.

So first gear gives plenty of power but little speed whereas fifth gear provides little power but plenty of speed.

The crankshaft only connects to the transmission when the car is in gear and the clutch is engaged. If you press down on the clutch the crankshaft disconnects from the transmission.

The transmission is connected to the output shaft, which is connected to the axles, which are connected to the wheels. When the transmission rotates the output shaft this turns the axles, which in turn rotate the wheels.

Other Key Car and Car Engine Components

Alternator: turns mechanical energy into electrical energy. This energy powers a car's electrics, from lights to wipers. It also recharges the car battery. A belt that rotates once the engine is on powers it.

Brakes: cars use either drum or disc brakes. Disc brakes use a caliper to press onto the disc of the wheel in order to slow the wheel down. Drum brakes work on the same principle however a drum brake presses against the inside of the drum.

Camshaft: controls the opening and closing of the intake and exhaust valves.

Cooling System: car engines produce a lot of heat. This heat needs to be controlled. To do this water is pumped through passages that surround the cylinders and then through the radiators to cool down.

Distributor: operates the ignition coil making it spark at exactly the right moment. It also distributes the spark to the right cylinder and at the right time. If the timing is off by a fraction then the engine won't run properly.

Exhaust System: once the fuel-air mix has been burnt the remaining gas enters the exhaust system and is expelled from the car. If a catalytic converter is present the exhaust gas passes through it and any unused fuel and other certain chemicals are removed.

Handbrake: this is a separate system from the foot brake. As a rule it is mounted on the floor of the car and is connected by a cable to the two rear wheels.

Head Gasket: the cylinder head (a block that seals all the tops of the cylinders) and the engine block (which contains the main bodies of the cylinders) are separate components that need to fit seamlessly together. The head gasket is a piece of metal that sits between them and connects them.

Oil: a car engine consists of many moving parts. Oil lubricates these parts and allows them to move smoothly. In most car engines oil is pumped out of the oil pan through a filter that removes any dirt and then is squirted under high pressure onto the bearings and cylinder walls. The oil then trickles down to the sump where the process starts over.

Regulator: regulates the amount of energy in the alternator.

Shock Absorbers: also known as dampers, are fitted between the car's body and axle in order to prevent excessive rolling and bouncing of the car body during motion.

Suspension System: counteracts the effects of hitting bumps in the road. Without such a system a car would veer of course every time the tyres hit a bump or pothole. The system comprises of springs and shock absorbers. The springs absorb any of the energy released when the tyres roll over a bump and the shock absorbers absorb the energy from the springs. This keeps the main body of the car steady and stable.

Timing Belt: a belt connected to both the camshaft and crankshaft ensuring that they work in time with each other.



What is the difference between a Petrol and Diesel Engine?

In petrol engines fuel is mixed with air and then forced into the cylinders where the fuel-air mix is compressed by the pistons and ignited by spark plugs. In a diesel engine the air is compressed before the fuel is added to it. When air is compressed it heats up. This means that when the fuel is added to the compressed air it is very hot and the fuel-air mix ignites automatically. So there are no spark plugs in a diesel engine as pressure is used to ignite the fuel-air mix.





A number of people don't realise that turning on the air conditioning actually reduces the number of miles per Iitre of your car. There is energy used in removing the heat (cooling) and moisture/humidity from the air in the car, and this consumes fuel because of the extra engine load.

How your heater and Air Conditioning A/C Works.

Without the conditioning systems in today’s modern vehicles, we would all be miserable driving to our destinations. We take for granted the heat that keeps us warm in the winter months, and the cool air that refreshes in the summer time. Let’s take a look at how both systems work to keep us comfortable all year round.

The heater in your car is basically a smaller version of your cooling systems radiator. Hot engine coolant is circulated through a small radiator, often times called a heater core. A fan is positioned in front of the heater core to blow cold outside air over the fins. As this air travels over the heater core, it heats up and becomes the hot air which blows out your heater vents.

Like your engines cooling system radiator, the heater core can suffer some of the same issues. If the heater core becomes clogged with rust or sludge, you will no longer have heat. Also leaks can cause a cabin full of white steam and really mess up your windows. If you smell the sweet aroma of coolant when your heater is on, chances are, you have a small leak in the heater core. Often times the heater core is buried under the dashboard, and replacing it, is a major job.

The air conditioning system in your car is comprised of a compressor, condenser, expansion valve and evaporator. If you have ever used a can of compressed air to clean computer components, you will know that the bottle gets very cold in a short amount of time. This is due to the rapid expansion of the compressed gas. The same thing happens in your car’s air conditioning system. Refrigerant (AKA Freon) is compressed in the compressor and turns into a hot gas. In the condenser, this hot gas is cooled to a liquid state and travels to the expansion valve. As the Freon goes through the expansion valve it returns to a low-pressure gas and rapidly cools in the evaporator. A fan blows over the evaporator and cools the air that eventually blows out your vents.

Click Here For An Excellent Illustration and Further Explanation.

Common Problems:

  • From time to time the A/C system needs to be recharged to bring it back up to maximum efficiency. Sometimes a leak may cause loss of refrigerant and will need to be fixed before refilling. It's difficult to tell if a leak is present without specific test equipment so let it up to a professional.
  • In recent years, the EPA has phased out the use of R-12 Freon in all refrigeration systems and R-134 has become the new standard. If you have an older system with R-12 you may need to retrofit your system to handle the new R-134 refrigerant. Sometimes seals, hoses and even the compressor need to be changed. The problem arises when the older seals and hoses are not compatible with the new oils found in the R-134.
  • Corrosion will cause the heater core (secondary radiator) to leak. This will manifest itself by leaving steam into the passenger compartment and fogging your windows. You will know there is a leak by the sweet smell coming from your vents. Unfortunately changing the heater core is usually not the easier job in the world as engineers tend to squeeze them into some pretty tight spaces under the dash.






The electrical system of any vehicle performs the same function, to deliver and monitor electrical power to various devices and sensors while under control of a computer system.


As cars continue to evolve, so do their auto-electrical systems. Today, your car’s auto electrical system controls almost every driving function. That’s why ensuring these systems and devices are working correctly is the only way to ensure your car runs well.



How does the auto electrical system work?
Modern cars are now fitted with sophisticated engine and body control systems that monitor speed, engine temperature, fuel usage, outside air temperature, transmission operation, air conditioning and much more. With this level of complexity, the system continuously monitors electrical circuits to ensure every component is operating within the range intended. Any faults or variances outside the operating parameters are logged by the system where, usually, a warning light will display to advise the driver that something is not operating correctly.

Auto electrical system components


As well as the central system, there are various other elements that form part of your auto electrical system including your car battery. These include sensors, actuators, alternators, battery charging systems, oxygen sensors, solenoids, air valves, step-up motors and other devices. All these elements work together to deliver improved power and performance with reduced fuel consumption and emissions.


The warning signs


Some of the signs that there are problems with your auto electrical system include:

  • Car won’t start.
  • Battery warning light comes on.
  • Check Engine warning light comes on.
  • Engine cuts out when car is moving.







External parts of Cars are :



axle : a metal bar that connects a pair of wheels on a car or other vehicle

body : the painted metal outer part of a car or other vehicle that gives it its shape


bonnet :  the front part of a car that covers the engine.

Dickey/ boot :  the covered space at the back of a car, used for carrying things in.

bumper : a long thin bar of metal or plastic fixed to the front or back of a vehicle, designed to protect it if it hits anything

chassis : the frame and wheels of a vehicle

exhaust : an exhaust pipe

fender :  a part of a vehicle that covers or protects the area round a wheel

filler cap :  the small round lid that covers the hole where you put the petrol in a car or other vehicle

grille : the radiator of a motor vehicle

hubcap : a metal cover for the central part of a wheel on a car

mudflap : a piece of rubber that hangs behind a wheel of a vehicle and stops dirt from the road from hitting the vehicle

muffler :  a silencer on a vehicle



the side of a car or other vehicle that is closest to the edge of a road on which you are driving

number plate



an official sign on the front and back of a motor vehicle, with numbers and letters on it that show who it belongs to. The American word is license plate.

the offside



the side of a vehicle that is nearer to the middle of the road. The side that is nearer the edge of the road is the nearside




used about parts of a vehicle that are nearest the middle of the road

panel : a piece of shaped metal that forms part of the body of a vehicle

petrol tank :  the part of a car or other vehicle that you fill with petrol.

rear end : the back part of a vehicle

roof : the top outer part of a vehicle

running board : a step outside the door of a vehicle

silencer :  an object that reduces the noise from a vehicle’s engine.

stabilizer : a part on a vehicle or machine that keeps it steady or in the correct position

sunroof : a part of a roof of a car that can be opened

tailgate :  a door at the back of a car

towbar : a metal bar on the back of a vehicle used for towing another vehicle

wheels : a round object that turns round and round to make a car  move

wheelbase : the distance between the front and back wheels of a vehicle

windscreen :  the large glass window at the front of a vehicle. The American word is windshield.

windscreen wiper :  a long thin tool that moves across a vehicle’s windscreen to wipe the rain off it

wing :  the part of a car that covers the wheel.

wing mirror :  a small mirror on each side of a vehicle. The American word is side-view mirror.

wiper : windscreen wiper