Research On Control Method Of Operating Stability Of Hydraulic Free Piston Engine

Hydraulic Free Piston Engine(HFPE) fully embodies the spirit of people going after power machinery which has higher efficiency and lower consumption. It is creatively integrated two-stroke internal combustion engine and hydraulic pump into an unit. It directly outputs hydraulic power which is utilized to rotate hydraulic motor or generator. It can also decrease most of the energy loss during multistage transmission by using this simple structure. With the rapid development of modern technology, HFPE has made great progress in terms of theory and practice.Based on the research at home and abroad, this thesis presents the demand for hardware framework of the engine control system. On the basis of these requirements, this thesis has made some in-depth description in electronic control unit, sensors and actuators and built a hardware control system which matches with the engine prototype. The purpose of these studies is to design a control system hardware framework that ensure stable operation of the hydraulic free piston engine. At the same time these studies laying the foundation for the design of functional modules and control strategies following in the next passage.Because of the extensive hardware aspect of HFPE control system, this article mainly focuses on the injection functional module. Firstly, detailed theoretical and practical exposition has been made on injection timing. On the premise of the precise injection timing, this thesis also do much in-depth study on boost circuit and achieved good learning outcomes. The boost circuit is an important part of the injector drive module. Meanwhile, the paper do some improvement on control scheme of brushless dc drive motor belongs to high-pressure pump that to ensure stable of common rail’s and injection’s pressure.Secondly, this paper describes the motion control, timing control, frequency control and compression ratio control of HFPE according to the need of engine control strategies in stable operationIn consideration of the precise control of the bottom dead center that has a great impact on the compression ratio and operation frequency. This paper studies its impact on the stable operation by elaborating bottom dead center’s mitigation measures and position control.Finally, based on the test bench, sample data is obtained pretreatment after experiment. And the paper describes the significance of this work. According to the experimental data, a meticulous study on various conditions of operation has been made to verify the feasibility of operating stability and control method of HFPE which is proposed in this paper.