The Development of Engine-in-the-Loop (EIL) Testing Methodology for Front Loading Emission Investigations 2023-01-0371

The introduction of more stringent emission regulatory standards, such as China 6 and Euro 6, with test cycles that are more representative of real-world driving, from WLTP to RDE presents significant challenges to the emission development of internal combustion engine program. In the typical development process, the emission development requires complex work such as after-treatment development and calibration optimizations. In addition, it is late in the process, after the prototype vehicle that is more representative of the production status is ready. To address the situation outlined above, an Engine-in-the-Loop (EIL) testing methodology is developed at SAIC Motor, to front load part of the emission development work to the engine testbed early in the development stage, in the face of ever compressed vehicle program development time.

This methodology is to emulate vehicle operations on the engine testbed. Key techniques are developed to achieve this. Simulation models are developed to be used in the SAIC’s engine testbed environment, including vehicle model, road model, driver model, simplified transmission model. Engine dynamometer dynamic capabilities is enhanced by realizing high dynamic torque control. Residual bus simulations are created, to simulate missing CAN signal from the vehicle CAN bus on the engine test bed, so that real ECU could function properly. An integration platform is established, so that the signals and data from real-time simulation models are connected with test bed automation system through high speed dyno CAN. These key techniques ensure that engine operates normally on the test bed in a virtual vehicle testing environment.

This paper presents the detailed development of the methodology, the validation of the methodology with comparisons between vehicle RDE test cycle results and EIL testbed results. Effect of RDE route on the emissions is also investigated using EIL method.