The best cycle for compression-ignition engines is the: a. Otto cycle b. Diesel cycle c. Rankine cycle d. Brayton cycle

b) Diesel cycle

Explanation:

A diesel cycle is also called compression ignition cycle in which first air is allowed to enters the engine cylinder and then it compresses up to a specified limit. After compressing the air, fuel is supplied through a nozzle. When fuel comes out from this nozzle then large number of drops let form and it burns the air fuel mixture. So this is called sparks compression engine.

On the other hand in petrol engine, first air-fuel mixture prepare in the carburetor and then allows to enters in the cylinder. So this is called sparks ignition engine.