In spite of occasional criticism they have attracted, hybrid vehicles (HVs) have been warmly welcomed by industry and academia alike. The key advantages of an HV, including fuel economy and environment friendliness, however, depend greatly on its energy management strategy and the way its design parameters are “tuned.” The optimal design and sizing of the HV remain a challenge for the engineering community, due to the variety of criteria and especially dynamic measures related to nature of its working conditions. This paper proposes an optimal design scheme that begins with presenting an energy management strategy based on minimum fuel consumption in finite driving cycle horizon. The strategy utilizes a dynamic programming approach and is consistent with charge sustenance. The sensitivity of the vehicle’s performance metrics to multiple design parameters is then studied using a design of experiments (DOE) methodology. The proposed scheme provides the designer with a reliable tool for investigating various design scenarios and achieving the optimal one. 1. Introduction Rapidly shrinking fossil fuel resources and growing environmental concerns have motivated a great deal of research on hybrid vehicles. Strict emission standards and rising fuel prices have encouraged manufactures to move away from conventional vehicles. Hybridization of conventional vehicles has proven to be the most efficient short-term solution to the problem. Hybrid vehicles enjoy attractive features such as the ability to shift the operating point of the internal combustion engine (ICE) according to a control plan, the restoration of brake energy, and the ability to switch to a pure electric mode in case of hybrid electric vehicle (HEVs). Integration of an additional energy source (battery) leads to an extra degree of freedom (DOF), since the propulsion force can be provided either by the ICE or by the electric machine (EM), and thus a suitable energy management strategy (EMS) should be used to control this diversity. Development of an EMS is an important task in the design of hybrid vehicles and the literature is relatively rich on this topic [1]. The design of an EMS is commonly treated as a dynamic optimization problem where the causality is not a major concern. Furthermore, selection of the proper topology (including transmission) and proper sizes of the power source components (sizing) are treated as extra layers of the optimization problem in recent hybrid propulsion studies [2] (see Figure 1). Those extra layers are mainly concerned with the reduction of fuel consumption and
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