Introduction to Hybrid Vehicle System Modeling and Control

Chapter 6: Energy Management Strategies of Hybrid Vehicle

6.1 Introduction

As stated in previous chapters, hybrid electric vehicles, using a combination of an ICE and electric motor(s), have become a viable alternative to conventional ICE-based vehicles (Powers and Nicastri, 1999). The overall performance of an HEV with respect to fuel economy and emissions reduction depends on the efficiency of the individual components and good coordination of these components. In other words, the energy management strategy (also called power control strategy) in an HEV plays a very important role in the improvement of the fuel economy and reduction of emissions.

Although there are a variety of HEV configurations, achieving maximum fuel economy, minimum emissions, and lowest system cost are the key goals of HEV energy management strategies. In addition, the following problems are often taken into account in the development of HEV energy management strategies:

• Optimize engine operation points/region—The operation points of the engine are set on the optimal points of the torque–speed plane based on the engine mapping data of fuel economy and emissions, as well as compromising between fuel economy and emissions.
• Minimize engine dynamics—The operating speed of an engine is regulated in such a way that any fast fluctuations are avoided, hence minimizing the engine dynamics.
• Minimize engine idle time—The engine's idle time needs to be minimized in order to improve fuel economy and decrease emissions. ...