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Rotating Torque Measurements -
Rotary Shaft Torque Measurement
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Rotating Torque
Measurements
Automotive engine torque is a measure of the force
required to rotate an object about an axis, e.g. the force provided by the
engine to rotate the drive train.
Due to frictional and mechanical losses in
various drivetrain components, the measured rotational torque at the driven
wheels will be approximately 20% less than the torque measured at the engine
crankshaft.
The equation for rotating torque measurements for a force applied at right
angles to the axis is as below:
Torque = Distance * Force
Where Distance is the
distance from the axis of rotation.
For example, a motor mechanic exerts a force of 4N at right angles to a wheel
wrench the is 0.25 meters in length. The resulting Torque will therefore be 1.0
Nm.
Automobile engines produce torque over a range of rotational speeds. The engine
under test rotational speed determines the amount of rotational torque.
The more powerful an engine is, the greater the amount of
torque
that can be
generated.
A chassis dynamometer, is a piece of kit used to measure engine torque and
rotational speed. This enables
engine horsepower to be calculated. typically a
chassis dynamometer
comprises a pair of flat bed rollers over which the test vehicle wheels are
positioned. The test vehicle wheels are then rotated to drive the dynamometer
rollers.
