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The purpose of his paper is to further the understanding of NVH test techniques for hybrid electric powertrains. It addresses dynamometer testing specifically. Due to the nature of the hybrid electric function, which includes situations when the engine is not running as well as different ratios of torque for power component combinations, typical testing methods are not adequate. Hybrid electric testing requires unique test conditions, dyno control, instrumentation and analysis. This paper attempts to establish some test standards directed specifically to the data needs of hybrid electric power trains.

The purpose of this paper is to explain a methodology for diagnosing noise and vibration of internal components of the automatic transaxle and particularly for park disengagement clunk. The method for determining contributing lash is three-fold. First the lash values are physically measured. Secondly, in-vehicle test data is taken using accelerometers, microphones, and stress gages. The data is taken at a baseline condition and then when various lash interfaces are set at zero. Thirdly, component impact testing can be done to identify noise contributing parts. For the condition of park disengagement clunk this method helps to diagnose the source of the noise. When a vehicle is parked on an incline and the transaxle put in park, there is an energy transfer of the weight of the vehicle through the transmission and onto the suspension of the vehicle. When the transmission is pulled out of park, the released energy results in a loud clunk. The clunk has a high and low frequency content.