Experimental and numerical research on the performance characteristics of OPLVCR engine based on the NSGA II algorithm using digital twins

Abstract

In order to optimize the fuel consumption and NOx emissions of engine and develop the general simulation–optimization platform on the performance and emissions of engine, this paper is pioneered in developing digital twins using GT-Power software for engine with a OPLVCR mechanism. First, an experimental investigation is carried out, and a corresponding 1D GT-Power simulation model is developed and validated for engine without VCR system. Then, a novel solution of VCR was proposed and analyzed in detail, and a new 1D GT-Power model with the new VCR mechanism was built by coupling with Matlab codes, and then the 1D model was validated by a full-size 3D simulation model with detailed combustion chamber, intake and exhaust port of the OPLVCR engine at CR 14.5:1. Thirdly, the digital twins engine model takes the spark timing, EGR rate, VVT_I, VVT_E as well as compression ratio as the inputs of the simulation optimization platform for OPLVCR engine based on the NSGA II algorithm. Finally, the optimal combination of compression ratio and EGR rate was validated by the full-size 3D simulation model of OPLVCR engine. The results show that BSFC and NOx is reduced by 16.37% and 74.18% based on NSGA-II algorithm. Thus, an integrated platform for engine performance optimization and verification has been developed. Furthermore, the model and data in this paper can be applied to evaluate and optimize the energy distribution by changing different technologies or optimization methods in the future.