A Commander–Tracker–Executor based energy management framework for an engine waste heat recovery system

Abstract

Energy management for an internal combustion engine waste heat recovery system presents a complex problem. There are the coupling issues of energy recovery and energy utilization. In addition, there are the problems arising from the large thermal inertia of the energy network. A Commander–Tracker–Executor energy manager framework is proposed as the management solution. Under this approach the Commander is designed to optimally split the engine’s exhaust energy among the different energy devices of the energy network at the lowest fuel cost. A disturbance estimation-based receding horizon controller is designed as a Tracker to follow the Commander’s commands in real time. The Commander’s decisions are made in real time based on each energy device’s efficiency model, the torque demand given by the driver, and the corresponding heat rejection requirement of the whole system. The Tracker works as a trajectory follower to transform the Commander’s decisions into the actuators’ control objectives. The Executor ensures that the energy management goals are achieved in line with the actuators’ control objectives. An energy network constructed of <Engine>- <Power Turbine>- <Organic Rankine Cycle System>- <Electric Cooling system>- <Battery>- <Integrated starter and Generator> has been taken as an example for the simulation study. The simulation results indicate that: the manager exhibited fairly good fuel-saving potentiality along a whole driving cycle; the proposed Commander showed effective exhaust energy splitting performance; and the Tracker scheme demonstrated good tracking capability and robustness.