RDE Plus - A Road to Rig Development Methodology for Complete RDE Compliance: Road to Chassis Perspective 2020-01-0378
To aid Original Equipment Manufacturers (OEM) in meeting future Real Driving Emissions (RDE) regulation criteria across extended environmental conditions, a Road to Rig (R2R) whole vehicle development, calibration and verification approach, currently known as RDE Plus (RDE+), has been developed at HORIBA MIRA. This paper compliments a summary paper by the same authors, which provides an overview of the RDE+ methodology and HORIBA MIRA’s vision for future vehicle development.
Within the present paper, the methodologies required for replicating real RDE road tests on a chassis dynamometer are discussed in depth. These include: application of robot driver for successful cycle replication and repeatability, use of HORIBA’s Multi-function Efficient Dynamic Altitude Simulation (MEDAS) system in conjunction with a climatic test cell to replicate the engine, vehicle and environmental conditions experienced during the road tests and use of IPG Car Maker for Vehicle-in-Loop (ViL) activities.
For cycle replication using the robot driver, two methods are presented: a “load matching” method whereby robot driver pedal inputs are controlled in an open-loop fashion and “speed matching” whereby the robot driver maintains the recorded vehicle speed via its own closed-loop control. The former is presented as an elegant way to achieve an exact match to a previously driven RDE test. The latter focuses on how robot driver controller tuning is used to successfully replicate real world driving if road loads are already known. For both load matching and speed matching cases, there was an excellent correlation in work done and tailpipe CO2 emissions across several road RDE cycles with NOx, CO and PN emissions also correlating well with the real road test values. Details of the exact figures are presented in the current paper.
Considerations relating to the application of HORIBA MEDAS are covered, including potential modifications to vehicles in pursuit of successful replication outcomes. Finally, the integration and application of IPG CarMaker within the chassis dynamometer environment will enable ViL testing and the ability to simulate, accurately and confidently, any desired test cycle within a wide envelope of environmental conditions
Alex Mason, Philip Roberts, Steve Whelan, Yosuke Kondo, Leo Brenton