With the development of high-speed rail technology, the interaction between wheel and track becomes more serious, which threatens the running stability, riding quality and safety of the vehicle. Due to the selected stiffness and damping parameters, conventional passive suspensions cannot fit in with the diverse conditions of the railway. Additionally, among these vibrations contains a large amount of energy, if this vibrational energy can be recycled and used for the active suspension to control, it will be a good solution compared to the conventional passive suspensions. Many energy-harvesting shock absorbers have been proposed in recent years, the most popular design is the electromagnetic harvester including linear electromagnetic shock absorbers, rotational electromagnetic shock absorbers, the mechanical motion rectifier (MMR), and the hydraulic electromagnetic energy-regenerative shock absorber (HESA). With different energy converting mechanisms, the complicated effects of the inertia and nonlinear damping behaviors will severely impact the vehicle dynamic performance such as the ride comfort and road handling. In the past few years, engineers and researchers have done relevant researches on HESA which have shown that it has good effects and proposed several suspension energy regeneration solutions for applying to car. This paper presents a novel application of HESA into a bogie system for railway vehicles comparing to the conventional suspension systems. HESA is composed of hydraulic cylinder, check valves, accumulators, hydraulic motor, generator, pipelines and so on. In HESA, the high-pressure oil which is produced by shock absorber reciprocation could be exported to drive the hydraulic motor, so as to drive the generator to generate electricity. In this way, HESA regenerate the mechanical vibrational energy that is otherwise dissipated by the traditional shock absorber as heat energy. Because the bogie has two sets of suspension systems, a dynamic model of bogie based on AMESim is established in order to clarify the influence of the dynamic characteristics effect and the energy harvesting efficiency when installing the HESA into different sets of the bogie. Then, set the HESA model into each suspension system of the bogie and input with the corresponding characteristic excitation, the influence of the dynamic characteristics and the energy harvesting efficiency are analyzed and compared. The simulation results show that the system can effectively reduce the vibration of the carriage, while maintaining good potential to recycle vibratory energy. Based on the results of the simulation, the relationships as well as differences between the first suspension system and second suspension system have been concluded, which are useful for the design of HESA-Bogie. Moreover, comparing the energy harvesting efficiency discrepancy between the two suspension systems, the potential of energy harvesting of a novel railway vehicle bogie system with HESA has been evaluated and then the best application department has been found, which indicates the theoretical feasibilities of the HESA-bogie to improve the fuel economy.

With the increasing of the train load, the wheel-rail wear is worsening, the maintaining and replacing cycle is shortened enormously, the problem of replacing steel rail and wheel prematurely not only make the railway transportation cost increasing, but also affect the railway normal transportation. This paper proposes a novel type of active energy self-supply radial steering technology — the parallel interconnection hydraulic-electric energy-harvesting active radial steering bogie system. This system is a typical “machine – electric – hydraulic” coupling system, which includes parallel interconnection hydraulic-electric energy-harvesting suspension and active radial steering bogie, consisting of mechanical, electronic, hydraulic and control subsystems internally. In this system, the radial steering bogie is equipped with four HESA, and HESA can reuse the mechanical vibration energy which used to be transformed into waste heat by the shock absorber. In this system, the mechanical vibration energy is now used to drive power module of active radial steering bogie, so as to implement the train’s active radial steering without external power supply. This paper discusses the evolution of radial steering bogie in general, and introduces the structure and basic principle of the parallel interconnection electro-hydraulic energy-harvesting active radial steering bogie system. The system establishes a model of the parallel interconnection hydraulic-electric energy-harvesting shock absorber. The typical vertical irregularity of American track is established. In the paper, we research on the system’s damping performance and energy recovery performance through stimulation. Simulation results show that the maximum vertical acceleration of train body is reduced from 42.9% to 62.3%, and the average energy recovery power from the system increases from 217W to 1835W when the system works at the six levels of track irregularities.

Currently, the onboard applications of many electronic devices that could benefit rail operation are hindered by the lack of availability of electrical power in freight cars. Although the locomotives, of course, have available sources of power, the freight cars usually don’t have any. The systems presented in this paper are meant to provide a solution for distributed power in freight trains. Although ideas like Timken’s generator roller bearing or solar panels exist, the railroads have been slow in adopting them for different reasons, including cost, difficulty of implementation, or limited capabilities. The solutions presented in this paper are vibration-based electromechanical energy harvesting systems. With size and shape similar to conventional shock absorbers, these devices are designed to be placed in parallel with the suspension elements, possibility inside the coil spring, maximizing underutilized space. As the train goes down the track, the suspension will accommodate the imperfections and its relative displacement will be used as the input for the harvesting systems. The first prototype generation used a linear generator, with the advantage of no need for a mechanical transformation of the input. They have proven that they could work but present some limitations in terms of power and efficiency. The second generation of prototypes is built around a rotating generator. The linear input motion is transformed into rotation by a ball screw. The possibility of including a gearbox to increase the speed is the key to greatly improve performances. The latest built prototype has shown during lab tests that it is capable of providing up to 75W RMS with displacements and velocities that resemble the relative motion across a vehicle suspension.