Subtopic: Calculation of power, torque, fuel consumption, heat load and power losses
Question Statement:
In a complete heat balance test of a four-stroke tractor diesel engine operating at full load, which of the following percentage ranges represent typical distributions of total fuel energy input?
Options:
(A) Brake power (useful mechanical shaft work): $32\text{--}38\%$
(B) Heat carried away by engine cooling water: $25\text{--}32\%$
(C) Heat carried away in dry exhaust gas and incomplete combustion: $28\text{--}35\%$
(D) Radiation, convection, and unaccounted losses: $5\text{--}10\%$
Answer Key:
A, B, C, D
Step-by-Step Solution & Explanation
All four ranges reflect standard empirical heat balance sheets of modern diesel engines:
- Useful Brake Work: $\approx 35\%$
- Coolant Heat: $\approx 28\%$
- Exhaust Enthalpy: $\approx 30\%$
- Radiation and Stray Losses: $\approx 7\%$
Total sums to $100\%$ of total fuel calorific energy input.