What is the mechanism of a car engine?

This blog post will answer the question, ‘What is the mechanism of a car engine?’, and cover topics like different parts that allow the car engine to run, how does each part contribute to running the car engine, and different areas of application of engine mechanisms

What is the mechanism of a car engine?

A typical car engine follows this pattern of work:

  • 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.

Different parts that allow the car engine to run

The following are the different components that allow a car engine to run 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 contribute to running the car engine?

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.

Different areas of application of engine mechanisms

These are the different configurations of car engines where the engine mechanisms are used.

Straight engine

In this type of engine, the cylinders are arranged in a straight manner and parallel to the car from the front to the rear. These are prevalent in powerful cars like Mercedes-Benz and BMW.

Inline Engine

This type of layout includes the cylinders placed adjacent to each other and in an upright manner. They are spread out across the engine bay and are perpendicular to the car, thus forming a small and compact kind of engine. This is common in small family cars and hatchbacks.

V Engine

In this type of engine layout, the cylinders are aligned in a V shape when viewed from the front. The cylinders are aligned in a manner that they form a 60-degree angle.

They are mainly prevalent in high-performance vehicles like supercars and other luxury vehicles.

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 mechanism of a car engine?’.

We obtained an understanding of the different parts that allow a car engine to run and the ways in which they help do so. Furthermore, we discovered different areas of application of engine mechanisms Please feel free to comment on the content or ask any questions in the comments section below.

Frequently Asked Questions (FAQs): What is the mechanism 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


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