The NVH Behaviour of a Powertrain Fixed on a Measurement Bench

The adaptation of a powertrain on an engine test bench could raise some problems concerning the torque transmission solution if it is changed from the classical schema (Fig. 1) (Crankshaft → Internal gearings of the gearbox → Differential → Transmission shafts) to a different configuration needed for the test bench operation (Fig. 2) (Crankshaft → Coupling shaft between the engine crankshaft and user → Eddy current dynamometer). Thus, by making different modifications, various problems can occur, such as NVH and reliability problems. This paper describes the study which was performed for the behavior of the powertrain system of a Dacia Logan K7M710 engine, by keeping the standard mountings of the engine and also by adding an extra fixation on the bench frame in order to stiffen the structure of the test bench. All these were correlated with the measurement on the vehicle.