Phenomenological Traffic Simulation as a Basis for an RDE Development Methodology 2019-26-0346
Pollutant emission and the fuel consumption of vehicles are increasingly becoming the focus of public and legislative attention. According to the Euro 6d standard, vehicles must comply with emission limits on the test bench and on the road. This paper discusses a methodology that enables RDE compliance and robustness testing of engines and propulsion systems based on phenomenological traffic simulation on the test bench.
The method is based on a road-to-rig approach. A real route is digitized and a virtual prototype of the target vehicle is built that models the driving resistances and properties of the real prototype. After comparing the speed profile to a real measurement, the robustness evaluation using variations can begin.
Traffic has a major impact on the result. In order to take a diverse range of traffic situations into account for the robustness evaluation, an approach to phenomenological traffic simulation was developed that does not require a complex definition of virtual traffic objects. The traffic situations are modeled by means of artificial road signs on the route. Within the boundary conditions, the driver model decides on the dynamics with which the virtual vehicle is driven through traffic.
The traffic situations that can be simulated on route sections originate from a real driving database. These are classified, weighted in terms of traffic density and route type, and distributed along the digitized route. Corresponding scenarios are subsequently generated for virtual test driving.
The presented methodology allows projects on the engine test bench to be evaluated in terms of RDE robustness early on, uncover potential problems at an early stage and reproduce these for optimization. It allows the complex and cost-intensive use of vehicle prototypes during PEMS measurements to be significantly reduced and investigations to be begun at a much earlier stage of the development process.
Jochen Petters, Guanlin Gao, Christian Donn, Wolfgang Zulehner
IPG Automotive GmbH
Symposium on International Automotive Technology 2019