RDE Plus – A Road to Rig Development Methodology for Whole Vehicle RDE Compliance: Engine-in-the-Loop Replication and Emulation

To aid Original Equipment Manufacturers (OEM) in meeting real-world driving regulation criteria across challenging boundary conditions of temperature, altitude and driving style throughout different territories, an integrated Road to Rig (R2R) whole vehicle development, calibration and verification programme known as RDE Plus (RDE+) has been developed by HORIBA. Connecting road, chassis dynamometer, Engine-in-the-Loop (EiL) and virtual testing methodologies, OEMs can frontload real-world driving scenarios further upstream during vehicle and engine development programmes to ensure compliance with localised regulations. Reported in this paper are the results from the replication of several road tests covering a multitude of altitudes and temperatures adopting an EiL methodology; feedforward of recorded pedal inputs and engine speed. Environmental characteristics of the route were emulated using a HORIBA Multi-function Efficient Dynamic Altitude Simulation (MEDAS) system with thermal encapsulation hardware adopted as part of the EiL strategy in order to emulate under-bonnet conditions. For all replicated routes there was an excellent correlation in engine performance and emissions for road, chassis dynamometer and EiL methodologies. The measured shaft torque from these replications were then used to prove-out the third stage of the HORIBA Torque Matching technique that allows elegant replication and emulation of real-world driving using minimal instrumentation and without any prior understanding or real-time measurement of the route characteristics or road load. For this technique, the engine and dynamometer are operated with closed loop control of the shaft torque and feedforward of engine speed. This technique results in the same driven work done across the cycle regardless of changes to the environmental conditions, hardware or software. Thus, allowing any effects of these changes on vehicle and engine performance and emissions to be decoupled from one another.