An I.C. engine develops indicated power of 150 kW. If the mechani
| An I.C. engine develops indicated power of 150 kW. If the mechanical efficiency of the engine is 80%, then brake power delivered is
A. 187.5 kW
B. 120 kW
C. 200 kW
D. 180 kW
Please scroll down to see the correct answer and solution guide.
Right Answer is: B
SOLUTION
Concept:
Mechanical efficiency is defined as the ratio of brake power (delivered power) to the indicated power (power provided to the piston).
It can be defined as the ratio of the brake thermal efficiency to the indicated thermal efficiency.
\({\eta _m} = \frac{{bp}}{{ip}} = \frac{{bp}}{{bp + fp}}\)
Calculation:
Given:
Indicated power = 150 kW, Mechanical efficiency = 80%
\(\eta_m = {Brake~ power\over Indicated ~power}\)
\(0.8 = {Brake~power\over 150}\)
Brake power = 120 kW.