The introduction of the Worldwide Harmonised Light Vehicles Test Procedure (WLTP) and Real Driving Emissions (RDE) test requirements have put increased strain on vehicle and engine performance as well as the development of advanced engine technologies and emissions mitigation strategies. This requirement for increased development is a direct result of the need for new vehicles to comply with present and emerging emissions standards across an extended range of boundary conditions that include ambient temperature, altitude and driving style.
To reduce the significant number of on-road test permutations that would ordinarily be required to validate a given vehicle across the defined RDE boundary conditions, a Road to Rig (R2R) development approach known as RDE Plus (RDE+) is being evolved at HORIBA MIRA. This will enable real world driving scenarios to be developed and deployed much further upstream during the development lifecycle of the vehicle and engine using aspects of virtual calibration; the aim being to significantly reduce vehicle and engine development costs and associated timescales.
On-road RDE data is presented in this paper from vehicles of different powertrain technologies gathered from several European test locations under conditions representing the boundaries defined by the RDE protocol. Upon gathering a combination of vehicle CANBus, custom instrumentation and emissions (Portable Emissions Measurement System (PEMS)) data, recorded RDE routes were replicated on a chassis dynamometer with a view of developing a standardised practical approach to replicate RDE tests in the laboratory environment.
Lab tests were performed at HORIBA MIRA in the Advanced Emissions Test Centre (AETC) with the aim of defining a chassis dynamometer test methodology suitable for different powertrain technologies that results in accurate representations of on-road conditions with respect to vehicle load, ambient temperature, altitude and emissions.
Following the road to chassis dynamometer correlation, the vehicle engines will be installed on an engine dynamometer with the objective of developing a suite of “worst case” RDE cycles using an Engine-in-the-Loop (EiL) format complemented with a Design of Experiments (DoE) type mapping approach. These “worst case” cycles, most likely operating near to or at the RDE boundary condition limits, can then be adopted for engine and vehicle development purposes as well as providing evidence of complete RDE compliance. The methodology to develop this EiL strategy in combination with a detailed overview of RDE+ project as a whole is presented in this paper.