Mechanical Engineering - Thermodynamics - Discussion

Otto cycle works on constant volume and 2 isentopic process.

Otto cycle works on constant volume and 2 isentopic process.

Otto cycle works on petrol engine so this is a constant volume process so option C is correct.

There are 2 isochoric and 2 isentropic processes. It works on petrol engine also.

Otto cycle or petrol cycle :- the volume remains constant.

Process 0-1 a mass of air is drawn into piston/cylinder arrangement at constant pressure.

Process 1-2 is an adiabatic (isentropic) compression of the air as the piston moves from bottom dead centre (BDC) to top dead centre (TDC).

Process 2-3 is a constant-volume heat transfer to the working gas from an external source while the piston is at top dead centre. This process is intended to represent the ignition of the fuel-air mixture and the subsequent rapid burning.

Process 3-4 is an adiabatic (isentropic) expansion (power stroke).

Process 4-1 completes the cycle by a constant-volume process in which heat is rejected from the air while the piston is at bottom dead centre.

Process 1-0 the mass of air is released to the atmosphere in a constant pressure process.

No answer is correct, in option C during compression stroke temp should increase. Option C can be correct if cycle start from 3.

But the maximum temperature in otto cycle at point 3 in T-S diagram.

I think there is something wrong in all figures.

2 constant volume and 2 isentropic process.

Otto cycle consist of two constant volume & other two is isentropic.

So C is right answer.