What does a car engine do?

This blog post will answer the question, ‘What does a car engine do?’, and cover topics like different parts of a car engine and their anatomy, how does a car engine work, and terminology related to a car engine.

What does a car engine do?

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

Different parts of a car engine and their functions

These are the different parts of a car engine and a complete breakdown of their structure and functions.

Name of the partMaterialFunctionManufacturing method
CylinderHard grade cast ironStores gas under pressure and guides pistonCasting
Cylinder headCast iron/AluminumSeal the working end of the cylinder and block entry/exit of gasesCasting/forging
PistonCast iron/AluminumReceives gas pressure and transmits thrust to connecting rodCasting/forging
Piston ringsCast ironSealing piston and cylinderCasting
Gudgeon pinHardened steelSupports and allows connecting rod to swivelForging
Connecting rodAlloy steelTransmits piston load to crankForging
CrankshaftHigh tensile forgingConverts reciprocating motion of piston to rotary motionForging
Main bearingsSteel/Bronze backReducing friction between partsCasting
FlywheelSteel/Cast ironHandles speed fluctuationsCasting
Inlet valveSilicon chrome steelPushes air/air-fuel mixture into cylinderForging
Exhaust valveAustenitic steelDischarges combustion productsForging

How does a car engine work?

Typical car engines or an internal combustion engine usually works in a 4-stroke cycle. These are some of the main parts that participate in this cycle and the way they occur.

Cylinder head

This is the passage through which the fuel enters the cylinder and exhaust gases are discharged. Its main components are camshafts, spark plugs, and the different valves.

Cylinder block

This is the place where the combustion of the air-fuel mixture takes place. The main components that make up the cylinder block are pistons, the combustion chamber, and the crankshaft.

Oil sump

The oil sump makes up for the lower section of an engine block. Its main components are oil filters and an oil pan.

The 4 stroke cycle occurs in the following steps.

Intake stroke

The piston is dragged down by the movement of the crankshaft to let the inlet valve inject the air-fuel mixture into the combustion chamber.

Compression stroke

This stroke involves the inlet valve closing and the piston moving upwards to compress the air-fuel mixture, thus making it more flammable and allowing the spark plug to ignite it.

Power stroke

The energy and force generated due to the explosion ignited by the spark plug push the piston downwards.

Exhaust stroke

The turning motion of the crankshaft makes the piston moves upwards and opens up the exhaust valve to discharge the combustion gases out of the cylinder.

The above is a representation of the work process inside a car engine.

Terminology related to a car engine


The inside diameter of an engine cylinder is called bore


The linear distance along the cylinder axis between two limiting positions is called stroke

Top dead center (TDC)

The topmost position of the piston towards the cover end side of the cylinder is called the top dead center.

Bottom dead center(BDC)

The lowest position of the piston towards the crank and side of the cylinder is called the bottom dead center.

Clearance volume

The volume contained in the cylinder above the top of the piston when the piston is at the top dead center is called the clearance volume

Swept volume

The volume swept through by the piston in moving between the top dead center and bottom dead center is called swept volume or piston displacement.

Compression ratio

It is referred to as the ratio of the total cylinder volume to the clearance volume.

Research has shown the most powerful engines to have been mounted in cars.


This blog post addressed the question, ‘What does a car engine do’.

We understood the anatomy of a car engine parts and the working of a typical car engine was discussed. Furthermore, some important terminology related to a car engine has also been provided. Please feel free to comment on the content or ask any questions in the comments section below.

Frequently Asked Questions (FAQs): What does a car engine do?

What is the function of an engine?

A car engine receives an air-fuel mixture from the intake valve and burns it to produce power that is transferred to the wheels via a crankshaft to make it move.

Why do you need an engine in a car?

The engine of a car helps produce all the power necessary to run a vehicle and without it, a vehicle cannot function.

When should I replace my engine?

With proper and regular care and maintenance, a car engine can be referred to as good for about 150000 miles after which they show serious issues and start aging fast.