What is Compression in Cars? Here is the Ratio List!
Compression literally means compression. In the compression process, it certainly generates pressure. Therefore, in the automotive world, compression is the compression of fuel in the vehicle's engine cylinder that creates pressure, causing the fuel to be sprayed and ignited by the spark plug.
Compression in cars is usually measured with a compression gauge. With this tool, you can know how much pressure is in your vehicle's engine cylinder. If the pressure is appropriate, it means your car is in good condition. However, if the pressure is low, your car usually lacks power when accelerated. Then you need to start looking for the cause.
What is the Difference Between Compression and Compression Ratio?
Some people think that compression is the same as compression ratio. The unit of compression is bar, Psi, kg/cm2, or KPa. Meanwhile, the unit of compression ratio has none, it is just a numerical comparison.
The compression ratio is the comparison between the volume when the piston is at Bottom Dead Center (BDC) and the volume when the piston is at Top Dead Center (TDC). Simply put, the compression ratio can be said to be the comparison between the total volume of fuel/cylinder space and the volume of compressed fuel/compression space.
Generally, the compression value of a healthy engine is between 9.5 to 15 bar. The minimum limit is 7 bar. If the compression of your engine cylinder is below 7, then you need to take special action. Usually, low compression is due to the engine's age and rust on the piston.
Meanwhile, the general compression ratio is between 9:1 to 11:1. This depends on the type of car. For example, the Daihatsu All New Xenia has a compression ratio of 11:1, the Daihatsu All New Sirion has a compression ratio of 10:1, and the Daihatsu Ayla has a compression ratio ranging from 9-10:1.
Up to this explanation, do you understand the difference between compression and compression ratio?
How to Calculate Compression Ratio
After you understand the definition of compression ratio, the next step is to know how to calculate the compression ratio.
The compression ratio generally has the formula:
CR = (V1 + V2) / V2
CR = Compression ratio
V1 = Cylinder volume (without combustion chamber)
V2 = Combustion chamber volume
For example, if a car engine cylinder has a volume of 150 cc (without combustion chamber) and the combustion chamber volume is 15 cc. What is the compression ratio (CR)?
CR = (150 + 15) / 15 = 11
Thus, the compression ratio of that car is 11:1.
Read Also: Here are the Differences Between Compression Piston Rings 1 and 2, Let's Check It Out!
List of Daihatsu Car Compression Ratios
The higher the compression ratio of a car, the more mechanical energy is produced. However, this also requires you to provide the appropriate fuel.
If the compression ratio is 10:1, then you must use Pertamax with a (Research Octane Number) RON of 92. If you provide fuel with a RON below this, your car will experience knocking.
Here is a list of Daihatsu car compression ratios:
- Daihatsu All New Sirion 1.3 - 10:1
- Daihatsu All New Xenia - 11:1
- Daihatsu Ayla - 9-10:1
- Daihatsu Ceria - 9.5:1
- Daihatsu Feroza - 9.5:1
- Daihatsu Taruna EFI - 9.5:1
- Daihatsu Gran Max - 10:1
- Daihatsu Luxio - 10:1
- Daihatsu Sirion - 10:1
- Daihatsu Terios - 10:1
That is the difference between compression and compression ratio, how to calculate the compression ratio, and the list of compression ratios of Daihatsu cars.
For those of you who want to get more information about car compression ratios, you can ask the technician when you are servicing your car at an official Daihatsu workshop.
