Undesired lateral force inevitably exists in a MacPherson suspension system, which is liable to damper rod's side wear and promotes the damper's inner friction decreasing the ride performance from the suspension system. Substituting a new side load spring with curved centerline for the conventional coil spring has been proven able to solve these problems and Multi-body Dynamics combining with Finite Elements Analysis may be an efficient method in optimizing its design. Therefore, taking a passenger car as example, a detailed multi-body dynamics model for the suspension system is built to simulate forces exerted on the damper and the minimization of its lateral component is selected as the design target for the spring. When the structure optimization of the side load spring is performed using FEA software ANSYS, its vertical and lateral elastic characteristics, supported by test data, are analyzed. After importing FEA results back to the suspension system, the dynamics simulation can be performed to validate the optimization result.

In this paper, a novel controller, the fractional order PD μ controller, is designed to improve the performance of the driver-vehicle system. First, fractional calculus and fractional order PI λ D μ controller are introduced. A control algorithm for vehicle directional control using the fractional order PD μ controller is then presented. Based on preview-follower theory, the on-line tuning method of the fractional order PD μ controller is designed. By comparing simulated and experimental results, the validity and robustness of the proposed fractional order PD μ controller in the closed loop system are verified. Finally, comprehensive evaluations are performed between the systems with the fractional order PD μ controller and with an integer PD controller. The results demonstrate that the use of the fractional order controller leads to an improvement of the performance of the driver-vehicle system.

No abstract

The printed circuit heat exchanger with high efficiency and good compactness and reliability presents potential application in the floating liquefied natural gas platform. This paper offers a review on technical characteristics and development trend of the printed circuit heat exchanger applied in floating liquefied natural gas, including the development state of printed circuit heat exchangers, the application state of printed circuit heat exchangers in floating liquefied natural gas, and the key issues for potential application of printed circuit heat exchangers in floating liquefied natural gas. Firstly, the existing research results of heat transfer and pressure drop characteristics of printed circuit heat exchangers with various flow channels are analyzed, and the correlations of the heat transfer coefficients and the pressure drop of these flow channels are summarized. Then, the application state of printed circuit heat exchangers in floating liquefied natural gas is introduced, and the functions of printed circuit heat exchangers used in the existing floating liquefied natural gas facilities are analyzed. Finally, the key issues for applying printed circuit heat exchangers in floating liquefied natural gas, including the structure design criteria, influence mechanism of sloshing conditions on performance, and methods of suppressing the adverse effects of sloshing conditions, are proposed. It is indicated that the present studies focus on the effect of single sloshing motion on the thermal–hydraulic performances of printed circuit heat exchangers, but few attention has been paid onto the coupling effects of multiple sloshing motions which conform more closely to the actual operation conditions of printed circuit heat exchangers in floating liquefied natural gas. Thus, the future work should aim at the influence mechanisms and structure optimizations in terms of thermal–hydraulic performance under multiple sloshing conditions.

No abstract