Anti-Idling Systems for Service Vehicles with A/C-R Units: Modeling, Holistic Control, and Experiments

Abstract

As people have begun to pay more attention to energy conservation and emission reduction in recent years, anti-idling has become a growing concern for automobile engineers due to the low efficiency and high emissions caused by engine idling, i.e., the engine is running when the vehicle is not moving. Currently, different technologies and products have emerged in an effort to minimize engine idling. By studying and comparing most of these methods, the conclusion can be drawn that there is still much room to improve existing anti-idling technologies and products. As a result, the optimized Regenerative Auxiliary Power System (RAPS) is proposed. Service vehicles usually refer to a class of vehicles that are used for special purposes, such as public buses, delivery trucks, and long-haul trucks. Among them, there are vehicles with auxiliary devices such as air conditioning or refrigeration (A/C-R) systems that are essential to be kept running regardless of the vehicle motion. In addition, such auxiliary systems usually account for a large portion of fuel from the tank. Food delivery trucks, tourist buses, and cement trucks are examples of such service vehicles. As a leading contributor to greenhouse gas emissions, these vehicles sometimes have to frequently idle to for example keep people comfortable, and keep food fresh on loading and unloading stops. This research is intended to develop and implement a novel RAPS for such service vehicles with the A/C-R system as the main auxiliary device. The proposed RAPS can not only electrify the auxiliary systems to achieve anti-idling but also use regenerative braking energy to power them. As the main power consuming device, the A/C-R system should be treated carefully in terms of its efficiency and performance. Thus, the developments of an advanced controller for A/C-R system to minimize energy consumption and an optimum power management system to maximize the overall efficiency of the RAPS are the primary objectives of this thesis. In this thesis, a model predictive controller (MPC) is designed based on a new A/C-R simplified model to minimize the power consumption while meeting the temperature requirements. The controller is extensively validated under both common and frosting conditions. Meanwhile, after integrating the RAPS into a service vehicle, its powertrain turns into a parallel hybrid system due to the addition of an energy storage system (ESS). For the sake of maximizing the overall efficiency, RAPS requires a power management controller to determine the power flow between different energy sources. As a result, a predictive power management controller is developed to achieve this objective, where a regenerative iv braking control strategy is developed to meet the driver’s braking demand while recovering the maximum braking energy when vehicles brake. For the implementation of the above controllers, a holistic controller of the RAPS is designed to deal with the auxiliary power minimization and power management simultaneously so as to maximize the overall energy efficiency and meet the high nonlinearities and wide operating conditions.