Objectified Evaluation and Classification of Passenger Vehicles Longitudinal Drivability Capabilities in Automated Load Change Drive Maneuvers at Engine-in-the-Loop Test Benches 2020-01-0245
The growing number of passenger car variants and derivatives in all global markets, their high order of software differentiability caused by regionally different legislative regulations, as well as pronounced market-specific customer expectations require a continuous optimization of the entire vehicle development process. Additionally, the continued increasingly stringent emission standards lead to considerable increases in powertrain hardware and control complexity. Also, efforts to achieve global market and brand specific multistep adjustable drivability characteristics as unique selling proposition, rapidly increase the scope for calibration and testing tasks during the development of the powertrain control units. The resulting extent of interdependencies between the drivability calibration and other development and calibration tasks require frontloading of development tasks. Usually, drivability calibration takes place towards the end of the vehicle development program as soon as a sufficient level of product maturity is achieved. Hence, for streamlining the entire development process, various powertrain engineering tasks have to be shifted from the overall vehicle level to component conception phases. In this context, highly dynamic “Hardware-in-the-Loop” (HiL) component test benches are the means of choice. Particularly for drivability calibration tasks, an objectified drivability evaluation and classification approach needs to be applied to heterogeneous testing scenarios at HiL test benches for the identification and evaluation of drivability influencing factors.
Before this backdrop, this article presents the transfer and validation of an objectification and classification approach for longitudinal vehicle drivability capabilities from vehicle level to highly dynamic “Engine-in-the-Loop” (EiL) test benches. First, for three different "engine control unit" (ECU) drivability calibration data sets (sport, medium and comfort), automated longitudinal drive maneuvers are performed in various gears and for different start conditions with a real vehicle on a proving ground. Subsequently, these test procedures are reproduced with the same combustion engine and ECU version at an EiL test bench. Thereto, modifications and enhancements to the test bench automation system as well as the real-time control models are required. Their influence on the objectified drivability test results and the degree of congruence between the drivability measurements on the road and the EiL test bench are determined. In this context, ICE related measurement data are presented for individual load change drive maneuvers. By utilizing a drivability objectification approach, the differences between the three ECU drivability calibrations are determined for both test scenarios. Furthermore, various characteristic drivability attributes are illustrated and explained for several gears for both test scenarios and also compared to each other. In addition, the gear specific identification and reflecting quality for the different characteristic drivability attributes for the three ECU calibrations are illustrated and discussed in detail by utilizing characteristic 3D diagrams.
Daniel Guse, Christian Heusch, Serge Klein, Timm Fahrbach, Jakob Andert, Stefan Pischinger, Stefan Tegelkamp, Martin Nijs, Johannes Scharf
RWTH Aachen University, FEV Europe GmbH