The internal combustion engines are responsible for transforming the chemical energy of fuels into mechanical energy, moving the vehicle. There are two main types of internal combustion engines: the Otto cycle engine and the Diesel cycle engine.
Otto cycle engine
The Otto cycle engine is the most common type of internal combustion engine found in automobiles. This engine works on a four-stroke thermodynamic cycle, which consists of:
- Intake: the air-fuel mixture is drawn into the cylinder;
- Compression: the mixture is compressed inside the cylinder;
- Explosion: the mixture is ignited by the spark plug, generating an explosion that pushes the piston down;
- Exhaust: the gases resulting from the explosion are expelled from the cylinder.
This cycle is repeated several times per second, moving the vehicle. The Otto cycle engine is known to be quieter and smoother than the Diesel cycle engine.
Diesel cycle engine
The Diesel cycle engine is less common in automobiles, but is widely used in trucks and buses. This engine works on a two-stroke thermodynamic cycle, which consists of:
- Intake: only air is drawn into the cylinder;
- Compression: the air is compressed inside the cylinder, increasing its temperature;
- Explosion: fuel is injected into the cylinder, spontaneously igniting due to the high air temperature;
- Exhaust: the gases resulting from the explosion are expelled from the cylinder.
This cycle is repeated several times per second, moving the vehicle. The Diesel cycle engine is known to be more efficient than the Otto cycle engine as it is able to extract more energy from the fuel. However, it is noisier and vibratory.
In summary, internal combustion engines are responsible for moving the vehicle by transforming the chemical energy of fuels into mechanical energy. There are two main types of internal combustion engines: the Otto cycle engine and the Diesel cycle engine, which differ in their thermodynamic cycles and operating characteristics.
