RDE Plus - A Road to Rig Development Methodology for Whole Vehicle RDE Compliance: Engine-in-the-Loop and Virtual Tools 2020-01-2183

The effects of driving style, traffic density and altitude on engine performance and emissions across multiple Real Driving Emissions (RDE) cycles were investigated using an Engine-in-the-Loop (EiL) strategy combined with a virtual toolset comprised of a virtual route, vehicle and driver. This is part of HORIBA’s Road to Rig (R2R) RDE Plus (RDE+) programme for whole vehicle RDE compliance.

An offline Design of Experiments (DoE) methodology was used to first parameterise a driver model to achieve a defined definition of driving style across the virtualised RDE route (itself created from an equivalent real RDE route) incorporating fixed traffic then for a fixed driving style with varying traffic density. By performing these scenario-based simulations in an offline format initially, complete compliance with RDE regulations for each of the scenarios being investigated could be achieved without the need for intensive testbed testing. Once offline driving style and traffic scenarios were developed and verified for RDE conformity, these were transferred to the EiL using an equivalent testbed specific virtual toolset in order to resolve cycle performance and emissions of the engine and vehicle.

There was a marked difference in engine out and tailpipe out emissions when driving style and traffic density were varied. These results therefore served to highlight the need for robust engine and vehicle calibrations in order to achieve RDE compliance, especially considering all driving scenarios tested complied with Euro 6d package 4 RDE regulations with the vehicle also operating within the moderate and extended RDE boundary conditions.

When the virtual RDE route was offset in altitude, there was a significant difference in engine out and tailpipe performance and emissions. By using the virtual tools and EiL methodologies defined here, a frontloading approach could therefore be adopted to ensure that appropriate technologies are specified during engine and vehicle development to ensure the engine and vehicle meet emissions legislation before prototype vehicles and physical testing is required.

This paper is the fourth in a series of technical papers from HORIBA on the RDE+ programme. It follows SAE Technical Papers 2019-01-0756, 2020-01-0376 and 2020-01-0378.