Question

The force acting in the connecting rod of a engine cylinder is F = 9000 N and the crank radius R = 75 mm. If the crank makes 4200 revolutions in 1.2 minutes, then find the brake work (Wb) in kilowatts.

Answer 1

Brake power is defined as the power developed by an engine at the output shaft.

Mathematically can be expressed as,

`W_b = (2\pi NT)/(60*1000)`

Where,

T = Torque

N = Number of Revolution

Torque is defined as the force by the distance applied, that is

`T = F*d`

`T = 9000*0.075`

`T= 675N\cdot m`

The number of revolution would be

`N = (4200)/(1.2)`

`N = 3500rev/min`

Finally the Brake power would be:

`W_b = (2\pi NT)/(60*1000)`

`W_b = (2\pi (675N\cdot m)(3500rev/min))/(60*1000)`

`W_b = 247.4W`