What is the function of a car engine?

This blog post will answer the question, ‘What is the function of a car engine?’, and cover topics like how a car engine carries out combustion, what are the parts that a car engine houses, and how does each part help the engine function.

What is the function of a car engine?

A car engine or internal combustion(IC) engine converts chemical energy from the combustion of air and fuel inside the combustion chamber into mechanical energy. This energy is transferred to the crankshaft via the upward and downward movement of the pistons and finally to the wheels to help the car move.

These are some benefits of IC engines over external combustion engines:

  • High efficiency
  • Simpler design
  • Low weight-to-power ratio
  • Low initial cost
  • Less storage space required

How a car engine carries out combustion?

This is how a car engine carries out the process of combustion:

  • The hot combustion gases that are produced at high pressure inside the combustion chambers are used as the driving force for the piston movements which in turn, helps drive the wheels.
  • The combustion cycle starts with the inlet valve permitting the entry of the air-fuel mixture into the cylinder.
  • The piston reacts to this by moving downwards followed by compressing the air-fuel mixture as it moves upwards.
  • The compressed air-fuel mixture is then ignited by the spark plugs.
  • This ignition is done at very high pressure and the impact makes the pistons move downwards to transfer that power to the crankshaft via the connecting rod.
  • As discussed earlier, only the lower end of the connecting rod moves in a circular motion while the upper end stays fixed and restricted to linear motion.
  • The power is then transferred to the crankshaft that further sends it to the car wheels via a transmission system and the driveshafts.

What are the parts that a car engine houses?

The following are the different components that allow a car engine to function and meet its optimal performance requirements:

  • Engine block
  • Combustion chamber
  • Cylinder head
  • Crankshaft
  • Camshaft
  • Piston(s)
  • Timing chain
  • Valvetrain
  • Valves
  • Rocker arms
  • Pushrods
  • Fuel injectors
  • Spark plugs

How does each part help the engine function?

These are the ways in which each of these parts helps an engine function according to performance requirements.

Every part making up the engine is crucial for its functioning and a small defect in any of them will hamper the overall performance of the car.

Engine block

The engine block acts as a housing for the pistons, crankshaft, camshaft, and cylinders depending on the vehicle. It is usually made up of aluminum or iron. Helps in creating a passage for water and oil to help cool down the engine and lubricate it.

Combustion chamber

Area of energy conversion during the combustion process. This is where the air-fuel mixture is ignited by the application of electricity from a spark plug and pressure from pistons.

Cylinder head

Its connection to the engine is done via connecting bolts and is sealed using a head gasket. It contains components like valves, pushrods, rocker arms, camshafts, etc.


It is mounted at the base of the engine box and is connected to the pistons via connecting rods. Its main role is to help move the pistons up and down with respect to the operating engine speed.


It is either mounted in the engine block or inside the cylinder head. It is responsible for controlling the timing of valves that need to open for letting in the air during the intake stroke and close for letting exhaust gases out during the exhaust stroke.


They are cylindrical in shape and have a flat head as the top surface. Its primary role is to convert the energy from combustion and transfer it to the crankshaft that helps to propel the car.

Timing chain

They act as the medium of connecting the crankshaft and the camshaft and ensure the engine timing is optimal. Their structure includes a heavy-duty rubber equipped with a set of cogs that grips on the crankshaft and camshaft.


The valvetrain is responsible for controlling the movement of the valves. It also acts as a housing for the valves, pushrods, rocker arms, lift rods, etc., and joins the cylinder head.


They are made up of intake and exhaust valves. The intake valves help the air-fuel mixture to enter the combustion chamber during intake strokes and the exhaust valve helps push out the unwanted gases at the end of the combustion process.

Rocker arms

The rocker arms along with the cams apply pressure on the two valves to either let in the air into the chamber or push out the exhaust gases.


For engines where the camshaft does not come in contact with the rocker arms, pushrods are deployed and are used to operate the valve system.

Fuel injectors

They are responsible for letting in fuel into the combustion chamber to be mixed with air and burned to produce energy.

Spark plugs

They are responsible for providing the spark necessary to burn the air-fuel mixture in the combustion chamber that helps in producing energy to push the piston down.

Research shows the various engine parts along with a pictorial representation to understand their roles better.


This blog post addressed the question, ‘What is the function of a car engine?’.

We understood how the engine helps to carry out the combustion process and the different parts and how they help the engine to function. Please feel free to comment on the content or ask any questions in the comments section below.

Frequently Asked Questions (FAQs): What is the function of a car engine?

What are the 3 types of engines?

The 3 types of engines are as follows:

  • Internal combustion engines
  • External combustion engines
  • Reaction engines

What are the 5 components of an engine?

The 5 main components of an engine are:

  • Engine block
  • Engine cylinder head
  • Crankshaft
  • Camshaft
  • Pistons 

What are the 4 main parts of a car?

The 4 main parts of a car include:

  • Car chassis
  • Engine
  • Transmission system
  • Car body


What was missing from this post which could have made it better?

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