Validation of Powertrain Systems Based on Usage Space Analysis Considering Virtual Road Load Profiles 2024-01-2424

Validation of powertrain systems is nowadays performed with specific durability relevant load cycles, which represent the lifetime requirement of individual powertrain components. The definition of such durability relevant load cycles, which are used for vehicle testing should ideally be based on the actual vehicle's usage. Recording driving cycles within a vehicle is one of the most typical ways of collecting vehicle usage and relevant end customer behavior, but the generation of such measured vehicle data can be time consuming. In addition, this method of capturing on-road measurements has limitations in the variation of vehicle loadings (e.g., number of passengers, luggage, trailer usage etc.). Especially for new applications, entering new target markets, these kinds of in-vehicle measurements are not possible in early development stages, as the required vehicle or powertrain configuration is not available in hardware or incapable of measurements. This paper shows a method to overcome these issues by replacing on-road measurements with virtual road load profiles generated by a software tool.

Throughout this process an approach named Usage Space Analysis (USpA) is performed. The purpose of USpA is to specify trips, which are representative for the usage behavior. To characterize each trip, vehicle usage parameters are calculated. This allows to draw a comparison between the trips. To be able to select relevant trips, a graphical representation of the usage space is done. The trips are visualized by characteristics, such as load, dynamics, and duration. In this study, the USpA method is demonstrated, either using real road load measurements or virtual track profiles generated in a software tool. A comparison of the single profile's accumulated damages on a few typical mechanical failure modes is made. Potential applications of the methodology for different powertrain systems and various failure modes are discussed.