How is horsepower actually measured for both wheel horsepower and brake horsepower? And are there limits to the technology that measures them?
In: Engineering
Horsepower is measured with a dynamometer which is any device that can measure torque and rpm at the same time.
For wheel horsepower it’s a pair of drums that the car sits on top of that work kindof like a car treadmill. (With the car held firmly in place to keep it from jumping off) A very basic dyno will just be a heavy known weight and by measuring rpm vs time you can tell how much power is generated by how quickly the drum spins up. Usually though it’s a motor/generator which can provide variable resistance and can calculate HP by measuring how much power is generated.
Similar thing with brake horsepower though usually that’s done with a motor mounted on a stand outside of a car with the motor bolted to the dynamometer.
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