A Transfer Methodology for RDE Development to a Powertrain Test Bench Using an Emission Prediction Model

The introduction of the RDE boundary conditions leads to an intensification of the development process with respect to the compliance of worldwide emission legislation, shorter development periods and cost savings while simultaneously increasing the number of product characteristics.
In the context of powertrain testing the VOCA-Approach (Vehicle Operating Condition Analysis) was developed as a part of the holistic “Road2Dyno”-Methodology. VOCA includes beside the collection of real customer driving data also whose systematic analysis and classification in a driving condition space according to the 3F-methodology. Results of this analysis are representative load spectra based on a damage matrix for characteristic components of the powertrain.
A new application is the usage of a VOCA-based procedure to achieve the requirements of RDE vehicle development. With a statistically verified base survey of a given vehicle using the modular APL-RDE-Track-Kit an emission model can be created and subsequently be used as an emission fingerprint with which the transfer to a test bench can be performed. An advantage of this procedure is that non-adjustable factors like weather condition and barometric pressure can be considered by using the emission model in a post processing routine. ... mehrSignificant emission influencing factors like driving behaviour, vehicle parameters and traffic flow can therefore be adjusted at the test bench by using a variance model. With the successful transfer of real driving conditions to the test bench the developing engineers have a powerful tool for calibration and development of a vehicle and its powertrain and exhaust aftertreatment. The drafted methodology also allows the testing of artificial RDE driving cycles, which are barely conforming to the law, to investigate and improve the vehicle´s emission behaviour and the constraints of a given calibration and hardware development stage.