Abstract:

For the problem of improper use of the service brake system due to unfamiliarity of the driver with the road conditions of heavy truck driving on long downhill sections， which leads to the risk of brake thermal degradation， this paper proposes an active control strategy of the exhaust brake system of heavy-duty trucks based on the identification of road driving conditions. Considering the difficulty of accurately obtaining the longitudinal gradient information of the road in mountainous areas and different characteristics of brake pedal action compared with other road sections， this paper selects the average brake pedal opening range in the time window， the continuous working time and the ratio of the brake pedal working time to construct the driving braking conditions on downhill sections and other road braking conditions. Then the hidden Markov model with continuous time series characteristics， including time window lengths of 30， 60， 90 and 120 s， are established by the causal relationship between the brake pedal action and the opening of the exhaust brake system. And off-line training and on-line identification verification are carried out using the test data of K25-K174 in the Ya’an-Xichang section of Jingkun Expressway. The road test and simulation results show that the control strategy proposed in this paper can accurately identify the driving conditions of the vehicle， realize the active control of the exhaust brake system， reduce the high dependence on the driver， and improve the driving safety of heavy-duty trucks on downhill sections.

Key words: automotive engineering, heavy-duty truck, driving cycle, hidden Markov model, active control