Master of Science, The Ohio State University, 2021, Mechanical Engineering
The problem of engine idling for long haul Class 8 trucks has been under study for decades, with APUs and Truck Stop Electrification as the most compelling solutions. With the electrification of trucks approaching feasibility in terms of cost effective technology, hybridization offers another degree of freedom to tackle the problem.
The research aims at exploiting the battery pack of a 48V mild hybrid Class 8 truck to store the sufficient energy for powering auxiliaries at night. This problem is not trivial, as the battery packs typically cannot recover the entire energy required through regeneration alone; hence an optimal energy management strategy needs to be employed to charge the battery through the engine during drive operation. Moreover, a tool needs to be developed to evaluate component bottlenecks, identify trends in engine torque requests and to establish a best-case baseline for an online energy management system.
The work presented aims to develop a Dynamic Programming framework that employs a multi-objective cost function to minimize fuel consumption and maximize regeneration. A typical Class 8 truck drive cycle is used to represent the drive phase, with mandatory stops as per regulations. The dynamic programming employs 3 control inputs: the engine on-off state, clutch engagement state and power request at the electric machine. An optimal SOC trajectory for the battery pack can then be established through the DPM function on Matlab. The framework also highlights the challenges associated with DPM such as rapid engine on-off scenarios, details the approach to tackle those and the compromises in fuel cost with those approaches. Finally, full cycle simulations with 2 candidate battery packs are presented and potential fuel savings are compared against ANL's report on idle reduction technologies.
Committee: Qadeer Ahmed Dr. (Advisor); Giorgio Rizzoni Dr. (Committee Member)
Subjects: Mechanical Engineering