Mechanical Engineering - Thermodynamics - Discussion

What is the Maximum temperature range produced in an IC engine cylinder?

Please answer me.

Compression ratio (r) = it is the ratio of total volume of cylinder to the clearance volume of cylinder.methematically,

r = total volume/clearance volume.

Vt = Vs+Vc.
Then r = Vt/Vc.

Both knocking and detonation are not same because the term knocking is define has when the piston is moves from TDC-BDC or BDC-TDC then the piston will deflects or it will get collides to cylinder due to this we feel some sound then we call its knocking.

Detonation is nothing but incomplete combustion.

Compression ratio for petrol 6 to 10.

For diesel 15 to 25.

What is the Compression ratio of CI engines?

Diesel fuel is much dense then the petrol or gesoline it is required high pressure and temp to burn so by using high compression ratio burning temp of the fuel is minimised. With the use of injector air and fuel mixture get inside in engine and burn with high compression in the range of 16-20 but in case of petrol engine which is much smaller size then diesel high compression is not possible so spark plug is used which is ignite the air fuel mixture comes from carburettor.

Self-ignition temp of petrol is about 450°c. That is why a spark plug is needed in si engines. Whereas in CI engines diesel self-ignites at about 180°c soo as soon as the compression starts the diesel self-ignites.

As per my knowledge, it is 16 to 20.

What 5&8 stands for? Please explain in detail.

Both knocking and detonation are the same term. In the case of petrol engine, it occurs due to pre-ignition. Due to some reason temperature of fuel become self-ignite temperature, so it generates flame before spark plug ignites. Now, when spark plug ignites, there will be 2 flames inside the cylinder and when they collide knocking sound occurs.