In addition to sufficient load-carrying capacity and good noise characteristics, research is increasingly focussing on the efficiency performance of gears.

The power loss of a transmission is composed of gearing, bearing, seals and other losses. The gearing losses form the major part of the transmission losses over the entire operating range of a transmission. They can be divided into load-independent (no-load) and load-dependent losses. The exact determination of these losses is important in the development of a transmission.

Efficiency investigations on oil- or grease-lubricated cylindrical gears are carried out with the FZG efficiency test rigs under different operating conditions, so that an assessment of the effects of macro and micro geometry of teeth, flank roughness, flank coating, lubricant and stress on frictional behaviour is possible.

Windage and churning loss investigations of assembled gearboxes are carried out on the FZG no-load test rig, so that the assessment of the impact of gear case, oil level, lubricant, temperature and rotational speed on no-load losses is possible. In parallel, oil distribution and no-load losses are determined by means of CFD simulations and validated with results of experiments.