The combustion chamber is the part of the internal combustion engine where the air and fuel mixture is ignited. It is a significant process of burning fuel and generating energy to power the car. Therefore, it has a direct impact on the engine’s efficiency and performance.
The combustion chamber consists of different components and each has a role to play in the process. Let us now go through what they are and what is the function of a combustion chamber.
The function of a Combustion Chamber
A combustion chamber is located between a piston head and a cylinder head of the engine. It consists of a piston, a spark plug, and intake and exhaust valves.
The burning of the air-fuel mixture takes place inside the combustion chamber. The carburettor delivers this mixture to the cylinder where it is combusted. This causes a buildup of the pressure of gases in the chamber which is forced into the expansion valve and expands. This high-pressure mixture exerts a force on the pistons, converting it into mechanical energy.
The energy obtained now moves flow from the pistons to the connecting rod and then into the crankshaft. When the crankshaft receives this reciprocating motion, it is converted into a rotatory signal. This energy is then transferred to the flywheel and transmission system, further to the drive shaft and into the wheels.
Parts of Combustion Chamber in Car Engines
Here we have laid down the parts of a combustion chamber as follows:
Spark Plug
A spark plug consists of a metal shell which is electrically isolated and screwed at the top of the cylinder head. It provides an electrical current to start the combustion and ignite the air-fuel mixture. A spark plug also acts as an energy dissipator by eliminating the excessive heat from the combustion chamber to prevent fouling.
Intake valve and exhaust valve
The intake and exhaust valves are responsible for controlling the airflow in the engine. The intake valve allows the entrance of air into the chamber before combustion and ignition. After the air-fuel mixture is ignited, it is exhausted through the exhaust valve. A camshaft
controls the motion of the valves so that they are in sync with the piston.
Piston
The piston is the movable part of the combustion chamber that slides back and forth to initiate combustion. The size of the piston determines the amount of pressure as well as the output power.
A piston transforms heat energy into mechanical energy. It also guides the movement of the connecting rod and controls the volume of the air-fuel mixture in the chamber.
The main parts of a piston are:
- The top part is called the crown and expands the most because it is in direct contact with the combustion gases.
- The piston rings bridge the gap between the piston and the cylinder in the form of a piston belt. They are in a pattern of grooves and the spaces between the grooves are piston land.
- The piston skirt is regarded as the side surface of the piston since it is subjected to thermal energy from different angles because of the motion of the connecting rod. A wrist pin is a hollow, steel tube that connects the piston to the connecting rod.
- The piston is connected to the crankshaft through a connecting rod. All these combustion chamber components together are called piston assembly.
Crankshaft
A crankshaft is a unit in the combustion chamber that converts vertical motion into rotary motion. It is a necessary component that is required to move a vehicle, as it delivers the power output in the form of rotational kinetic energy which rotates the flywheel.
Connecting Rod
A connecting or a conrod is connected to the crankshaft and carries energy from the piston to the crankshaft. A conrod must be mechanically strong because it is constantly subjected to stretching. This is why it is in the form of an I-beam and made of steel.
A con rod has two ends: a small end and a big end. Small-end is secured to the piston, while the big end is connected to the crankshaft. The base is called the rod cap and is fixed to the rod by bolts.
Types of Combustion Chambers
Now that you are aware of all the combustion chamber components, let’s take a look at the types of combustion chambers.
Combustion Chambers in S.I (Spark Ignition) Engines
In this type of combustion chamber, the combustion is initiated by a spark plug through an electric discharge.
There are different types of combustion chambers in S.I. engines that vary on the position of the spark plug, and engine valves such as
- T-head type
- L-head type
- F-head type
- I-head type
Combustion Chambers in C.I. (Compression Ignition) Engines
Compression engines are also called diesel engines where combustion occurs when the fuel injected into the chamber vaporises and mixes with the air. The continuous motion of the piston causes the mixture to reach the ignition temperature and combustion occurs.
There are two types of combustion chambers for C.I. engines:
- Direct injection type
- Indirect injection type
There are various designs for both direct and indirect types based on the position of the chamber and the fuel injector.
That’s a wrap-up on the combustion chamber of cars and their parts. The combustion chamber is a major element of the internal combustion engine and must be checked every now and then.
Apart from engine efficiency, it is also necessary as it houses important factors like mean piston speed which affect your car’s mileage. Therefore, when looking for used cars for sale in the UAE make sure it has a properly maintained combustion chamber to avoid any hassle.
Stay tuned to UAE’s top auto blog for more information on car parts and their functions.
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