The internal combustion engine is the engine installed in every auto vehicle. The internal combustion engine provides the power to run the auto vehicle. Autos, Cars, Lorries, and trains can not move without an internal combustion engine. The internal combustion engine is the lifeline of our transportation sector. Our life in this world will be standstill if the internal combustion engine were not existing. Internal combustion engine as the name implies combustion of fuel takes place inside the engine cylinder. This combustion of fuel develops power. Power developed in the engine cylinder exerts the thrust on the central shaft of the engine, which gives motion to the wheel connected to the central shaft. Thus, our vehicle starts running.
PARTS OF SPARK IGNITION ENGINE
TYPES OF COMBUSTION ENGINE
Depending on the process of ignition of fuel inside the engine cylinder, they are classified as follows:
(1)Spark Ignition Engine
(2)Compression Ignition Engine
SPARK IGNITION ENGINE
The spark-ignition engine works on the Otto Cycle. Spark ignition engine is mainly used in Cars, Busses, Boats, Aircraft, and Agricultural equipment. Spark ignition engine may operate on a 2-stroke cycle or 4-stroke cycle. In the 2-stroke cycle, there is one power stroke for each revolution of the crankshaft. In 4- stroke cycle there is one power stroke for every two revolutions of the crankshaft.
Most SI engines operate on 4- stroke cycle. Operation of 4- stroke cycle is explained below:
The intake valve opens and the exhaust valve remains closed. The piston moves down in the cylinder. This action brings the combustible mixture of fuel and air from the carburetor to the cylinder.
Intake and exhaust valves closed. The combustible mixture in the cylinder is compressed by the upward movement of the piston.
Intake and exhaust valves are closed. The compressed combustible mixture is ignited by a spark plug, and the expanding gases force the piston downward.
The exhaust valve opens and the Intake valve remains closed. Combustion gases are forced out through the exhaust valve by the upward movement of the piston.
COMPRESSION IGNITION ENGINE
The compression ignition engine works on the Diesel cycle. The compression ignition engine is rugged in construction. It is mostly used for heavy lorries, busses, and agricultural equipment. It is also used in power plants and marine propulsion equipment. CI’s engines also operate on 4- stroke cycle as SI engines do. In the compression-ignition engine, only air is inducted in the intake stroke. Air is compressed during the compression stroke, which increases the pressure and temperature of the air. At the end of the compression stroke fuel is injected into the hot compressed air, which ignites the fuel. No carburetor is used in the CI engine to prepare the fuel-air mixture for combustion. A fuel injection pump is used in the CI engine. In CI engines heat of compression of air ignites the fuel. The working of the diesel engine is in the following fig.