Engine Power Terminology — Indicated vs Brake vs Friction What is the name given to the actual usable power available at the engine crankshaft output?

Introduction / Context:
Engine power can be defined at different stages. 'Indicated power' is based on the in-cylinder pressure diagram (theoretical shaft-less output), 'frictional power' represents internal mechanical losses, and 'brake power' is the net power available at the crankshaft to do useful external work. Selecting the correct term is crucial in testing and performance calculations.

Given Data / Assumptions:

• Standard mechanical testing with a brake or dynamometer.
• Steady operating condition and known rotational speed.

Concept / Approach:
By definition: brake power is the shaft output measured by a brake or dynamometer; indicated power is the gross power deduced from cylinder pressure; frictional power is the difference IP − BP. Thus, the 'actual power supplied by the engine crankshaft' refers to brake power.

Step-by-Step Solution:
Relate powers: IP = BP + FP.Identify what is measured at the shaft: BP.Conclude the correct term: brake power.

Verification / Alternative check:
Dynamometer readings give torque and speed; BP = 2 * pi * N * T (in consistent units), confirming it is shaft output.

Why Other Options Are Wrong:
indicated power: does not account for mechanical losses, hence larger than shaft output.frictional power: a loss term, not an output.none of these: incorrect since 'brake power' is the standard term.

Common Pitfalls:
Using brake power and indicated power interchangeably; they are different and related by internal mechanical efficiency.

Final Answer:
brake power