Measure of Friction losses on Common Rail Engine 2000-05-0063

Past years, the decreasing of friction losses has been an essential factor in fuel consumption improvement of internal combustion engines and would be the key to reach the targets of lower CO₂ requirements in the beginning 2010's.

Nevertheless, improvements are going to be always lower and tests have to be more precise and decrease torque measurement error.

A solution consists in using a test bench equipped with an eddy current dyno for the positive torque phases coupled with a middle power electrical machine driving the engine.

The torque measurement is realised by the balance mounting of both Eddy current dyno and electrical machine. This measurement is permanently doubled by a torquemeter installed on the transmission shaft coupled with the crankshaft. This process allows to obtain the exactitude of the measured torque value.

This solution provides some great precision in friction losses measurements on the low torque values and keeps also the ability to do any measurements in positive torque values to validate specific consumption disparities between different technological solutions.

Realised tests show that such a system is able to measure the influence of piston rings or any other part of the engine, of which evolutions can have low incidences on the friction losses.

The results analysis shows advantages and drawbacks of the two torque measurement systems, and the repeatability and robustness of results both concerning friction losses.