Question

Why compression is needed before combustion?

Answer 1

Now days we are mostly using the four stock engines

In petrol engine the ignition take place after the compression of fuel and air mixture and generally this is the second stroke we consider.

But when we consider diesel engines there is only air present inside the cylinder bore and that is compressed and then fine drops of diesel come into contact with compressed air and the combustion take place only due to compressed air. that's why the diesel engines also have high compression ratio as compared to petrol engine.

And compression provides the ignition temperature to the fuel present inside the cylinder.

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