By incorporating turbocharged diesel engine and ISG motor, parallel mild hybrid heavy-duty vehicles achieve a better dynamic performance in startup and acceleration process. However, the involvement of ISG motor can also have an impact on the powertrain performance, which is defined as “Excessive ISG Involvement” and exhaustively investigated in this study. First of all, configuration of the powertrain is analyzed, and its main constituents are modeled. Then with the obtained powertrain model, simulations are conducted for investigation. An ordinary startup and acceleration process is first simulated to demonstrate the slow power response from diesel engine. A couple of variables are derived from the simulation result to describe driver’s power demand on diesel engine and the actually fulfilled portion. The problem of excessive ISG involvement is simulated thereafter, analyses are conducted with the variable couple to illustrate the underlying impacts. Based on the results and conclusions above, a demand deviation based dynamic coordinated control strategy is proposed for resolution. Validations are performed through dynamic process simulation, whose results present a 6.5% reduction in vehicle acceleration time, a 33.8% reduction in reference speed tracking error and a 9.2% reduction in energy consumption in contrast to the existing strategy, indicating the superior dynamic coordinated control performance.
Wang et al. (Thu,) studied this question.