How does a Diesel Engine Work ?
The only difference between a diesel and a gasoline engine is that the fuel is sprayed in the combustion chambers with the help of fuel injector just when the air pressure is high enough to ignite the fuel immediately. Diesel fuel is less volatile than gasoline and is much easier to start in combustion chamber if preheated state. All the manufacturers try to install little glow plugs, which will work off the battery to pre-warm the air in cylinders when we first start the engine. Better fuel management techniques at higher injection pressures can create much enough heat to burn the fuel without the use of glow plugs. The air is compressed with a compression ratio of 15:1 and 23:1.
When a light goes on, it means we step on the accelerator and turn the engine on. The fuel passes through some number of filters and clean fuel will be obtained. Proper filtering must be done to keep the engine healthy.
The fuel injection pump pressurizes fuel into the delivery tube. The delivery tube is known as rail which keeps at high constant pressure.
There are four strokes in Diesel Engines. They are as follows –
1. Induction Stroke
2. Compression Stroke
3. Power Stroke
4. Exhaust Stroke
Induction Stroke –
This Induction stroke is also known as intake stroke. In this stroke, the fuel and air enters the cylinder, i.e., the combustion chamber and the piston position is at the lowest end. The intake valve will be open and the exhaust valve will be closed. As the air and fuel enters inside the combustion chamber, this stroke is known as Induction stroke or Intake stroke.
Compression Stroke –
In this compression stroke, the air – fuel mixture gets compressed. At this stroke, both the inlet valves and exhaust valve will be closed and the piston moves to the top most position compressing the air and fuel mixture. As we see the compression of air and fuel, this stroke is known as Compression stroke.
Power Stroke –
This power stroke is also known as expansion stroke. At this point of time, the valves remain closed and the spark plug firing takes place. This makes the air – fuel mixture to ignite and combustion takes place. This combustion or explosion makes the piston to move downwards as the pressure drastically increases in the combustion chamber. This movement of piston is connected to the connecting rod which creates a mechanical motion with the help of crankshaft. As we observe the expansion, this stroke is known as expansion stroke or power stroke. Even in this stroke, both the valves, intake and exhaust valves remain closed.
Exhaust Stroke –
In this exhaust stroke, the inlet valve remains closed bu the exhaust valve remains open until the end of the exhaust stroke. The piston moves to the top position which moves out the waste combusted gas which is present in the combustion chamber. Again al the strokes continue to occur from the intake stroke.
This is the working of a diesel engine.