A thermodynamic cycle is a sequence or series of processes performed on a system, that eventually returns the system to its original state. Gas power cycles are thermodynamic cycles, which use air, as the working fluid. A gas power cycle may consist of heat transfer, work transfer, pressure variations, temperature variations, volume variations and entropy variations. In a gas power cycle, the source of heat supply and the sink for heat rejection are considered to be external to the working fluid.
Four different types of gas power cycles are commonly used. They are as follows:
While Otto cycle is widely used in petrol engines, Diesel cycle is used in Diesel engines. Dual cycle and Brayton cycles are extensively used in gas turbine engines.
The following video shows you how a petrol engine works using otto cycle: