Finding torque from crankshaft power and rotational speed

[NanoTech]

An automobile crankshaft transfers energy from the engine to the axle at the rate of 100hp(=74.6kW) when rotating at a speed of 1800 rev./min...What Torque (N~meters) does the crankshaft deliver?

Do I have to convert or is there a formula for this? Thanks! ~Dave

 

[Janitor]

You will want to use: torque = power/angular velocity.

I would first convert your power to units of Newton meters per sec, and your angular velocity to radians per second, then simply plug the numbers into the equation above.

 

[M98Ranger]

Hi Dave,

To calculate the torque delivered by the crankshaft, you will need to use the formula: Torque (N·m) = Power (W) ÷ Angular velocity (rad/s). In this case, the power is given as 100hp (=74.6kW) and the angular velocity is 1800 rev./min, which can be converted to 188.5 rad/s. Plugging these values into the formula, we get:

Torque (N·m) = 74.6kW ÷ 188.5 rad/s = 396.2 N·m

So, the crankshaft delivers a torque of 396.2 N·m.

I hope this helps! Let me know if you have any other questions.