# Diesel Engine Compression Ratio

Diesel engine compression ratio - as we know that diesel engines do not use lighters (spark plugs) for combustion, but instead use the heat that occurs due to very high compressed air. Air is compressed then the temperature will increase. The appropriate character of diesel fuel is diesel fuel that will burn itself if the room temperature reaches a certain hot temperature. Then the ratio of diesel engine compression is very in a note.

The ratio of compression to an internal combustion engine or an outer combustion engine is a value that represents the ratio of the volume of the combustion chamber from the largest capacity to the smallest capacity. This is a fundamental specification for almost all general combustion engines.

In a piston engine, the ratio is the ratio between the volume of the cylinder and the combustion chamber when the piston is at the bottom dead point and the volume of the combustion chamber when the piston is at the top dead point.

The compression ratio refers to the volume or amount of air and fuel mixtures that the engine cylinder can accommodate when it is empty (at the largest space size) compared to the volume when the cylinder is pressed by the piston and has the smallest space size.

Diesel engines and gasoline engines also have certain compression ratios with diesel engines likely to have higher compression ratios.
To calculate the engine compression ratio, the engine cylinder volume when the piston is at the bottom of the cylinder must be calculated first.

After that, the cylinder volume when the piston is at the top of the cylinder is also calculated. Currently, it is a mixture of compressed air fuel.

 Diesel engine compression ratio

### Compression ratio in diesel engine

Cylinder Displacement and volume of the combustion chamber determine the compression ratio of diesel engines. to calculate the compression ratio using the following formula:

Machine Compression Ratio = Total Fuel Volume (V0): Volume of Fuel When Piston In Top Position (V1)
Comparison of diesel engine compression between 11: 1 to 23: 1

while the gasoline engine or gas engine is only about 8: 1 to 11: 1
For example, the cylinder and combustion chamber with the piston below contains 1000 cc air. When the piston has moved to the top of the cylinder, and the volume remaining in the head or combustion chamber becomes 100 ccs, the compression ratio will be proportionally described as 1000: 100, or with a fractional reduction, 10:1 compression ratio.

The 13: 1 ratio, for example, means that the engine has a cylinder volume 13 times more when the piston falls compared when it is compressed.
On the cylinder, the amount of air-fuel mixture does not change, but simply is pressed into a smaller space to create a large explosion.

Diesel engines use compression to create combustion, while gasoline engines use sparks from spark plugs to burn air and gasoline mixtures.

The high compression ratio in a gasoline engine often creates a problem known as a machine tap/knocking.
However, a higher compression ratio will make the gasoline engine hit by a knocking if using low-octane fuel or otherwise known as detonation. This can reduce efficiency or damage the engine if the knocking sensor does not exist to impede time. However, the tap sensor has become the OBD-II standard specification of the 1996 and newer car outputs. On the other hand, diesel engines operate on the principle of ignition compression, so unburned fuel will automatically cause an ignition delay, which will also cause the knocking of the engine.
Diesel engines, on the other hand, are designed for high compression in order to function properly.

The 13: 1 ratio is considered high in gasoline engines while diesel engine compression ratios range from 11: 1 to 23: 1, depending on the engine type.

The high compression ratio will generate more power by compressing the air and fuel more strongly, creating a stronger combustion.
The tight cylinder room will make the air and fuel better blended so that when more explosions occur than the evaporating mixture.

More evaporation is a sign of higher thermal efficiency, which means the engine performs better without using more fuel.

The disadvantage of a higher compression ratio on a gasoline engine is the possibility of a tap on the engine.
A knocking occurs when a larger explosion than desired occurs and causes the piston to move up or down too quickly.

A knocking will trigger a noisy sound and if not fixed will permanently damage the machine.

One way to prevent the knocking on the gasoline engine is to use gasoline with a higher octane.

That's why be sure to know the compression ratio of your vehicle engine and use the appropriate fuel.

Read too: Diesel Mechanic Automotive Repair