How a Car Engine Works: Step by Step detailed Discussion

how a car engine works step by step

Many of us want to know that How a car engine works step by step. In this article, I will try to answer it. The general principle of the thermal engine is simple, it is to exploit the energy produced by the combustion of an oxidizing/fuel mixture in a closed chamber. In burning there is a significant expansion of the gases that are exploited (depends on the rate of engine compression, itself linked to the segmentation, valves etc.). The pressure induced by the combustion then pushes the piston downwards which is itself connected to the wheels (not directly obviously…). The whole thing happens in a loop cycle that depends on the type of engine you are dealing with (2 or 4 times).

How a Car Engine Works Step by Step

Here is a very good overview of the operation of a petrol engine thanks to the animated diagram mentioned in the video. You can observe the operating steps that are cut in 4 strokes, hence the name of the 4-stroke engine. However here you can see only one cylinder in working order.

Step 1: Air Intake + fuel

A mixture of fuel and air arrives since the inlet (in the case of direct injection the fuel is sent directly into the combustion chamber without going through the intake).
The air/fuel mixture is carried out either in the carburetor, in the inlet or in the combustion chamber (depends on the type of engine). In case of problems with the calculator (or probes) the dosage can be bad and the engine works less well (loss of power, fumes etc…).
Note that the presence of a turbo allows increasing the volume of air in the admission

Read More About:  List of Engine Components


The AIR/fuel mixture has just entered the combustion chamber by the inlet duct which closes immediately (if it remains open no compression), the piston in its momentum of the previous cycle comes to compress the mixture to Height of about 30 bars. Until here still no combustion/explosion.

Step 3: combustion/relaxation

Finally, there is a combustion/explosion! It is produced by the candle, which when the piston is at the top, produces a small spark (arcing) thanks to the ignition which sends the current (a dispenser sends the juice to the candle concerned through a rotary system, because all the candles of Motor must not be switched on at the same time. Each piston having a 4-cycle time lag with the others). The whole must be perfectly synchronized for the engine to work, combustion too soon or too late and nothing works as expected. The small spark ignites the air/fuel mixture which is very flammable! The piston is, therefore, propelled downwards, creating the mechanical energy that makes the car move. On the modern engines, there is a coil dedicated by candle, but the general principle remains the same, namely to send juice to the candles at the right time.

how a car engine works step by step

Step 4: Exhaust

When the combustion/explosion occurred, only the fumes caused by the combustion are left. The exhaust valve (which is almost the opposite of the inlet valve except that it is the outlet instead of the inlet) then opens quickly so that the piston expels the fumes. These fumes then go to the exhaust to end up in the air (a catalyst reacts chemically on the path of gases to reduce pollution).

I know, I am also a learner, but I tried my best to answer the questions how a car engine works in this step by step guide. If you know more about it please do comment in the comment section.

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