From a control perspective, the energy management system and the thermal management system of an electrified vehicle are often developed separately, which may not yield the optimal solution. Moreover, an optimal system design requires concurrent plant (topology and size) and controller optimization, which should apply to both energy and thermal domains. This paper originally provides a comprehensive analysis of design and control optimization layers to reveal the interconnections between them and how they influence the optimality of an electrified vehicle design considering both energy and thermal domains. It was found that energy and cost savings can be achieved by integrating these optimization layers, and the energy and thermal domains with four coordination schemes, namely, sequential, iterative, nested and simultaneous. There is a trade-off between optimality, causality, complexity and computational time. Additionally, future research directions in terms of reducing energy consumption and system costs of electrified vehicles are identified herein, such as using integrated design and control methods, employing electrified actuators, exchanging heat between powertrain components and utilizing waste heat recovery systems.

For an electric vehicle (EV) with a continuously variable transmission (CVT), a novel convex programming (CP)-based co-design method is proposed to minimize the total-cost-of-ownership (TCO). The integration of the electric machine (EM) and the CVT is the primary focus. The optimized system with co-design reduces the TCO by around 5.9% compared to a non-optimized CVT-based EV (based on off-the-shelf components) and by around 2% compared to the EV equipped with a single-speed transmission (SST). By taking advantage of the control and design freedom provided by the CVT, the optimal CVT, EM and battery sizes are found to reduce the system cost. It simultaneously finds the optimal CVT speed ratio and air-flow rate of the cooling system reducing the energy consumption. The strength of co-design is highlighted by comparing to a sequential design, and insights into the design of a low-power EV that is energy-efficient and cost-effective for urban driving are provided. A highly integrated EM-CVT system, which is efficient, low-cost and lightweight, can be expected for future EV applications.

Semiactive suspension (SAS) system has been widely used for its outstanding performance in offering competent ride quality, road holding, and handling capacity. However, the road friendliness is also one of the crucial factors that should be attached in the design of the SAS system for heavy-duty vehicles. In this study, a fuzzy controlled hybrid-acceleration driven damper (ADD) and ground hook- (GH-) control strategy is proposed for SAS system of heavy-duty vehicles. Firstly, a quarter-vehicle model with SAS system is constructed. Then, aiming to improve the ride quality and road friendliness, a hybrid-ADD and GH-control strategy is proposed under the coordination of the fuzzy controller. Numerical results show that the ride quality and road friendliness of the SAS system with the proposed control strategy outperform those with traditional hybrid-sky hook and ground hook-control strategy. It is also verified that the proposed strategy is superior to the sole ADD approach and sole ground hook approach in improving the vehicle overall performance.

This paper focuses on a ride comfort based suspension (RCS) system using an optimal stiffness-determination method. The proposed RCS system is composed of a variable hydraulic damper with gas chamber (VHDGC) and an air spring. In this work, the detailed structure, modeling process and parameter sensitivity of the proposed VHDGC are presented. Moreover, the mathematical relationship between the proposed damper and the air spring is considered. Numerical results reveal that the ride comfort of the proposed RCS system can be greatly improved as compared with the passive suspension. In addition, the overall performance of the RCS system is also guaranteed. In sum, the proposed RCS system is a promising solution in improving the ride comfort of the vehicle.

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