The BOSCH Chassis Dynamometer LPS 002 measures the dynamic wheel power and the power loss in the transmission, and displays the effective engine power (brake horsepower) directly as the sum of the two.

A test-roller set with a defined inertia effect (inertia flywheel) is driven and accelerated by the vehicle's driving wheels.

The power at the wheels can be determined from the acceleration of the Dynamometer mass with the engine running at wide-open throttle (WOT).

Upon reaching the measurement speed, the engine is disconnected from the remaining drive elements by declutching. The energy stored in the test-roller set now drives all the transmission elements with which the test rollers are in contact.

The power loss is determined from the deceleration resulting from the rolling resistance, and from the transmission and bearing resistance's.

Using the wheel power and the power loss, an electronic evaluation unit calculates the engine power at the clutch.

The evaluation circuitry measures the wheel power during acceleration and the power loss during deceleration.

In accordance with DIN 70020, the engine power is displayed at rated engine speed, referred to standard conditions of + 20C and an atmospheric pressure of 750 mm Hg (=1013 mbar), and with a permissible tolerance of + 5 %.

Non-standard atmospheric pressures and intake-air temperatures affect engine power, and must be taken into account during evaluation .

The test data required, "Engine power" and "Rated speed" are to be taken from the vehicle documents.