Why adiabatic process is required in heat engine?

[avistein]

what is the need of adibatic process in heat engine? We can work only with isothermal process .Please expalin this.

 

[Simon Bridge]

You don't need an adiabatic process in a heat engine.
You only need a cycle.

 

[dauto]

You need a closed cycle with net work production. You won't get that with an all isothermic process.

 

[Sunfire]

what is the need of adibatic process in heat engine?

Practically, the adiabatic condition forbids the flow of energy from the engine into the surroundings. Quite often this simplifies the mathematical description of the system. But probably most importantly, serves to isolate the system from its environment and then the energy in it could be more efficiently used to do work, etc. In the case of cooling, the adiabatic condition will serve to thermally isolate the cold parts of the system from the warm surroundings.