Analysis of the Effect of Vehicle Platooning on the Optimal Control of a Heavy Duty Engine Thermal System 2019-01-1259
One promising method for reducing fuel consumption and emissions, particularly in heavy duty trucks, is platooning. As the distance between vehicles decreases, the following vehicles will experience less aerodynamic drag on the front of the vehicle. However, reducing the velocity of the air contacting the front of the vehicle could have adverse effects on the temperature of the engine. To compensate for this effect, the energy consumption of the engine cooling system might increase, ultimately limiting the overall improvements obtained with platooning. Understanding the coupling between drag reduction and engine cooling load requirement is key for successfully implement platooning strategies. Additionally, in a Connected and Automated Vehicle (CAV) environment, where information of the future engine load becomes available, the operation of the cooling system can be optimized in order to achieve the maximum fuel consumption reduction.
In this paper, a control-oriented physics-based model for the engine cooling loop of a Volvo engine is developed and validated against road data. Starting from the validated model, an optimal control problem for the coolant system is formulated considering the tradeoff between the tracking of the engine temperature setpoint and the corresponding fuel consumption under different trailing distances. To compare the coolant system performance, Dynamic Programming is used to determine the global optimal solution for the coolant system actuator (radiator fan). The coupling between optimal cooling system operation and reduction in ram air will be evaluated by comparing the results obtained from the DP under different platooning conditions against the unrestricted scenario. In addition, the paper will analyze the changes in the tradeoff between fuel consumption and setpoint tracking for different vehicle distances. This analysis will provide useful insight on the sensitivity of the coolant system controller calibration to the platoon distance.
Brian Block, Brian Huynh, Stephen Boyle, Stephanie Stockar, Stephen Geyer, Jian Li, Jeffrey Huber
Penn State University, Volvo Group Trucks Technology