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How Does a Car Work?

Omkar Phatak
Very few people really care to know about how a car works, as long as it does what it's supposed to and takes them where they want to go. If you are one of the few who are curious about the working of this technological wonder, then read on.
It is hard to imagine today what a world without cars would be like. They have revolutionized human transportation. Most people are not really interested in knowing how cars work, as it is possible to drive them, without really knowing what happens under the hood. Read on to know more about the working of these engineering marvels.
It is not just about knowing enough, so that you can know what may have gone wrong in a car. It is about appreciating the beauty of a machine in action. When you understand how every tiny working part contributes and works in harmony to propel a car forward, you can't help but be amazed and respect man's engineering genius.
The explanation here will be very brief and simplified. If you want to know more, you must dig deeper into books, that talk about the actual working of the automobile.

How Does a Car Function?

Working of the Engine

The heart of a car is its engine. It is a device which makes its motion possible. It comes in many types like the petrol and diesel engines. Here, the working of a generic engine is discussed.
In technical terminology, it is called an internal combustion engine. It derives force of motion, from the combustion of a fuel like gasoline or diesel. The explosive force created by the burning of fuels is converted into mechanical force.
An engine consists of multiple cylinders with movable pistons inside. Pistons are connected to the crankshaft. Every cylinder is a combustion chamber and is tightly sealed. Every working cycle of a car engine consists of four strokes:
  • Intake: The fuel is taken into the chamber in vapor form, with opening of a valve and the piston goes down.
  • Compression: The piston rises up while compressing the gaseous fuel.
  • Combustion: Either the fuel gets self-ignited under compression or it's ignited by a spark plug. When it ignites, it causes an explosion which sends the piston down again. This motion of the piston is conveyed through the crankshaft to the flywheel, which ultimately turns the wheels through the transmission.
  • Exhaust: The exhaust valve opens and the byproducts of combustion are released and directed through the catalytic converter (which filters out pollutant gases). From there, the gases are released through the tail pipe.
So, the energy released through chemical combustion is converted to mechanical motion of the piston and finally through the crankshaft, it turns the flywheel. That is how your car gets the force of propulsion and wheels get the torque which turns them.
Engine cycles like these keep happening in rapid succession, which gives the car more power and speed. Engine horsepower depends on how many such piston-based combustion chambers are connected to it.
For example, a V8 engine, used in formula one racing, has eight combustion chambers. The compression ratio decides the amount of power drawn from a combustion engine.

Battery Function

The car needs an electrical support system, that powers everything from the ignition to the car lights and air conditioning. The battery is a set of electrochemical cells, that are rechargeable. The car generates its own power through the alternator, which is a dynamo that charges the battery, when it's moving.


Car motion depends on the engine and a gasoline powered engine's four stroke cycle cannot begin without a spark, from the spark plug. When you put in the key and turn the ignition on, power is supplied to the spark plugs, which fire the engine cycle. That's why, it is called the 'Ignition', as it ignites the gasoline and starts the engine cycle.

Working of the Transmission

Speed control and systematic harnessing of engine power is done through the gear transmission. As you may know, this transmission is either manual or automatic. The torque generated in the flywheel is transmitted through the transmission system to the wheels.
Gears help in deriving maximum torque from the flywheel and they help in adjusting the speeds. The torque is transmitted to the wheels, from the transmission, through the drive shaft. The drive shaft turns the axle and the wheels attached at the ends of it.
Besides this, there are brakes which help in stopping the car, by absorbing the rotational torque. The accelerator causes it to move faster, by feeding more gasoline during every engine cycle.
Another important part is the steering system of the car, which is a bit too complex for me to explain here. It is synchronized in such a way that when the car turns, the two wheels turn in the right turning radii. There are a lot many more aspects, which I haven't covered here, except the most important ones.
To know more, you might want to check up with your mechanic, who will be delighted to give you the lowdown on it. You could also attack automobile engineering texts, which will give you a deeper and more clearer explanation. Automobiles are beautiful machines, which are testimony to the ingenuity of the ones who built them.