# Cylinder in a car engine

Question: I wanted to know why a shorter, wider cylinder in a car engine performs better than a taller, thinner cylinder of the same volume. I think it has something to do with power but I think there are other reasons as well.

The cylinder in a car (internal combustion) engine
The idea of the cylinder is to transmit energy to the wheels and the more often this can be done the better, Therefore a shorter stroke (movement up and down) is better since that will give a "kick" to the drive shaft more often. This is the power concept that you mentioned because more work can be done in a given time if the ignition of the fuel can be performed at this faster rate.

To consider the actual area of the cylinder:
Assuming a given pressure (P) in the cylinder and a cross sectional area A the force (F) downwards after the ignition of the petrol-air mixture is:

Force (F) = Pressure (P) x Cross sectional area (A)

Therefore for a given the pressure the force downwards is greater for the shorter stubby cylinder.

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