Engine-in-the-Loop: A Method for Efficient Calibration and Virtual Testing of Advanced Diesel Powertrains

This paper will present tools and use cases for Engine-in-the-loop (EiL) operation of diesel powertrains as one part of a virtualized calibration and testing process. Manufacturers of passenger cars and other light duty vehicles are facing tightening emissions standards and CO2 requirements, leading to an increase in powertrain complexity including different stages of hybridization and additional challenges to the engine and the Exhaust gas After Treatment System (EATS). In this context, virtualization is the key element in the development process to provide, on the one hand, a system level test environment at an early project phase without the necessity to build-up a demonstrator vehicle, and, on the other hand, to ensure a high calibration quality and emission compliance under all boundary conditions, while keeping the development effort and cost low.The first part of the paper will focus on the general setup of the hardware and communication between the different systems at a modern engine test bench architecture dedicated to applying the Engine-inthe-Loop approach in a virtual experimentation platform.The second part of the paper will elaborate on the diesel specific challenges of the engine operation in a virtualized environment. The repeatability and reliability of the transient behavior of the entire powertrain in general and in particular the EATS, is essential for substitution of chassis dyno tests by EiL testing. Therefore, conditioning of the engine and its components is implemented based on simulation models. This will be shown by the results of a use case with a modern 2l diesel engine. As an outlook, the extension of the EiL test bed to a virtual hybrid powertrain testbed is also presented, and the benefits for hybrid testing and operating strategy optimization are discussed.