Describe working of Heat engine

Heat engine is a device by which a system is made to undergo a cyclic process that results in conversion of heat to work.

 * It having of a working substance-the system. Eg. a mixture of fuel vapour and air in a gasoline.

 * The working substance goes by a cycle having of several processes. In some of these processes, it absorbs a total amount of heat Q₁ from an external reservoir at some high temperature T₁

 * In some other processes of the cycle, the working substance releases a total amount of heat Q₂ to an external reservoir at some lower temperature T₂