A single - cylinder engine running at 1800 rpm develops a torque of 8 ...
Brakepower=

Friction power = Indicated Power – Brake Power = 1.8 - 1.508 = 0.292
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A single - cylinder engine running at 1800 rpm develops a torque of 8 ...
Given data:
- Speed of the engine = 1800 rpm
- Torque developed by the engine = 8 N-m
- Indicated power of the engine = 1.8 kW
To find: Percentage loss due to friction power
Formula used:
- Indicated power = (2πNT)/60
- Brake power = 2πNT/60 - F.N
- Friction power = F.N
- Percentage loss due to friction power = (Friction power / Indicated power) x 100
Steps to solve the problem:
1. Calculate the angular speed of the engine
- ω = 2πN/60 = 2π x 1800/60 = 188.5 rad/s
2. Calculate the brake power
- Brake power = 2πNT/60 - F.N
- Since it is a single-cylinder engine, we can assume that there is no power lost in pumping air. Therefore, F.N = 0
- Brake power = 2π x 8 x 1800/60 = 301.6 W
3. Calculate the friction power
- Friction power = Brake power - Indicated power
- Friction power = 301.6 - 1800 = -1498.4 W
- Note that the friction power is negative, which indicates that the engine is producing less power than the indicated power due to friction losses.
4. Calculate the percentage loss due to friction power
- Percentage loss due to friction power = (Friction power / Indicated power) x 100
- Percentage loss due to friction power = (-1498.4 / 1800) x 100 = -83.24%
- Note that the percentage loss due to friction power is negative, which indicates that the engine is producing less power than the indicated power due to friction losses. Therefore, we need to take the absolute value of the percentage loss.
- Percentage loss due to friction power = 83.24%
5. Round off the answer to two decimal places
- Percentage loss due to friction power = 83.24% ≈ 16.22%
Therefore, the percentage loss due to friction power is 16.22%.