Experimental Verification of Discretely Variable Compression Braking Control for Heavy Duty Vehicles: Final Report

In the first two chapters of this report, the development of discrete compression brake and transmission models is explained. In the vehicle model development, special efforts have been put in transmission shifting scheduling. Transmission up-shift and down-shift scheduling are separated in the modelling. Hysteresis during shifting is introduced to reduce chattering. A compression brake effect on transmission shifting is identified and considered in the modelling. The new transmission shifting model has been validated through experimental data. The transmission shifting model is combined with the compression brake model and the model of the longitudinal vehicle dynamics for a high-fidelity predictive simulation software tool. Power-width-modulation (PWM) actuation for brake coordination is proposed to further exploit the capacity of the compression brake and reduce the usage of service brake.