An internal combustion engine with a capacity of 36 kW consumed 14 kg of gasoline for 1 hour

An internal combustion engine with a capacity of 36 kW consumed 14 kg of gasoline for 1 hour of operation. Determine the efficiency of the motor.

Given:

N = 36 kW = 36000 W;

t = 1 h = 3600 s;

m = 14 kg;

q = 44 MJ / kg = 44,000,000 J / kg is the specific heat of combustion of gasoline;

Efficiency -?

Decision:

Efficiency = A / Q * 100%;

N = A / t, A = N * t;

Q = q * m.

A = 36000 * 3600 = 129600000 J;

Q = 44,000,000 * 14 = 616,000,000 J;

Efficiency = 129600000/616000000 * 100% = 21%.