Study On Control Strategy Of Hybrid Electric Bus Based On Real-world Driving Cycle

Good economy and low emissions of Hybrid Electric Bus (HEB) have beenaccepted by the public in recent years. As an important mean to improvevehicle economy and reduce emissions，the control strategy of HEB hasbecome a hot topic. Aiming at improving the economy and reducing emission,the HEB control strategy is investigated aims to meet the power requirementsof the vehicle in accordance with its driving cycle, and to have engine andmotor work in the high efficiency area. Because no general control strategyexists for different models and different driving cycle, an applicable controlstrategy as well as its appropriate control parameters has to be selectedcarefully.Working on an actual research project, with the ‘Gas–Electric’ ParallelHybrid Electric Bus as the object for the study, this thesis investigated thecontrol strategy based on real-world driving cycle. The main topics covered inthis article include:(1) The background and the significance for the project, the quo of HybridElectric Bus and control strategy and the basic ideas and main researchaspects of this project were introduced.(2) A statistical analysis of the real world driving cycle of HEB wasconducted. Firstly, the concepts, classifications and development status ofdriving cycle were introduced. Secondly, the characteristics of bus drivingcycles were studied. Thirdly, driving cycle data for the research object, the‘Gas–Electric’ Parallel Hybrid Electric Bus,were collected and analyzed,providing a theoretical basis for the establishment of control strategies in thefollowing chapters. (3) A simulation model of the HEB was fully, according to the powertrainconfigurations of the ‘Gas–Electric’ Parallel Hybrid Electric Bus, a CRUISEvehicle model was built. The vehicle controller model was built in MATLAB/SIMULINK environment, based on the modeling rules and the real-world busdriving cycle.(4) Study on logic threshold torque distribution control strategy. With theengine torque and the battering SOC value being chosen as control objects,four types of rule-based logic threshold torque distribution control strategieswere proposed, namely, a), adapting both engine torque and battery SOCvalue, b), adapting engine torque and constraining battery SOC value, c),constraining engine torque and adapting battery SOC value, d), constrainboth engine torque and battery SOC value. Simulation results showed thatunder the premise of balancing battery SOC value, constraining both enginetorque and battery SOC value torque distribution control strategy can makegas consumption lower.(5) Study on the torque distribution control strategy based on theinstantaneous equivalent fuel consumption algorithm. Firstly theinstantaneous equivalent fuel consumption algorithm was introduced; thenthe objective function of instantaneous equivalent fuel consumption was built,followed by the establishment of the instantaneous optimization model inSIMULINK, which was then integrated into the vehicle control strategy. Threetypical driving cycles were simulated for real-time optimization, seekingpositive solutions to the present moment best engine torque and motor torque,according to the present moment best engine torque, engine torque outputcommand lookup table was built, then the logic threshold torque distributioncontrol strategy and command lookup table were combined to obtain theoptimized torque distribution strategy. Simulation results show that theoptimized torque distribution strategy can further reduce gas consumption, and maintain the balance of the battery SOC value better.