Determination of Power Losses Based on the Measurement in Closed Loop Test Bench for Automotive Gearboxes

This article deals with estimation of power losses on the closed loop test stand dedicated for endurance tests of automotive gearboxes. This test bench has got two specific properties. Firstly, the gearbox is connected to the bench in the same manner as in the vehicle which means that the gearbox is rigidly connected with the bolts to the engine cast and this assembly is than hung using rubber mounts to the test rig frame. Second specific property of this test bench is that it can be used either for one- or more-load level tests. The main target of this contribution is to describe the power flow in the closed circuit which means to find out power losses of its all parts based on the measured load. The measurement will be done for both pretensioning mechanisms which means for manually operated worm gear as well as planetary unit. The magnitude of power losses will be evaluated for different revolutions, load levels and speed stages.