LQTI EGR Rate and Boost Pressure Control of a Diesel Engine Assisted by an eBoost

Torque response delay is a major disadvantage for turbocharged engines, especially for large diesel engines, due to turbo-lag. A coordinated control strategy is proposed in this paper for a diesel engine equipped with an electric compressor (eBoost) system to significantly reduce turbo-lag. A multi-input, multi-output Linear Quadratic Tracking with Integral (LQTI) control strategy and scheduling logic is developed for the Ford 6.7L V8 diesel engine equipped with a variable geometry turbocharger (VGT), exhaust gas recirculation (EGR), and added eBoost and bypass valve. Note that the production engine does not have an eBoost and bypass valve. Multiple model-based LQTI controllers were designed at different engine load conditions based on associated linearized models and the control outputs were scheduled using engine load and bypass valve position. The developed control strategy is validated in simulation and experimental studies, and the test results show a reduction of intake manifold pressure response by over 73% compared with the production configuration without a significant impact on NOx emissions.