The internal combustion petrol engine can be modeled on the Otto cycle, the four stages consist of
(a) An adiabatic compression from V1 to V2,
(b) An isochoric (constant volume) pressure increase,
(c) An adiabatic expansion from V2 to V1 and
(d) An isochoric pressure decrease. Sketch the p – V diagram. Assuming that the gas behaves ideally, with a constant heat capacity, show that the efficiency is
n = 1 – 1/rγ–1
Where the compression ration r = V1/V2