CAJ | 학술논문

为了解决采用串联型液压混合动力系统车辆节能控制问题,该文在对串联型液压混合动力系统工作原理进行分析的基础上,考虑到系统的动态特性和液压储能器气体温度与热传递对储能器工作状态的影响,建立了系统数学模型.根据车辆行驶理论,考虑到车辆制动能的回收与再利用和串联型液压混合动力系统与发动机的匹配问题,设计了一种串联型液压混合动力系统综合控制策略,该控制策略通过主控制单元、液压泵控制单元、二次元件控制单元和发动机控制单元相互配合实现.运用 Matlab/Simulink 进行了控制系统仿真分析,仿真结果表明所设计的控制策略能准确实现驾驶员行驶车速要求,液压储能器能有效回收车辆制动能,在减速结束时能及时释放储能器能量以节约发动机所消耗的燃油,并能够使储能器能量耗尽时发动机及时介入保证车辆正常行驶.研究结果可为静液压传动车辆节能减排设计提供参考.
위료해결채용천련형액압혼합동력계통차량절능공제문제,해문재대천련형액압혼합동력계통공작원리진행분석적기출상,고필도계통적동태특성화액압저능기기체온도여열전체대저능기공작상태적영향,건립료계통수학모형.근거차량행사이론,고필도차량제동능적회수여재이용화천련형액압혼합동력계통여발동궤적필배문제,설계료일충천련형액압혼합동력계통종합공제책략,해공제책략통과주공제단원、액압빙공제단원、이차원건공제단원화발동궤공제단원상호배합실현.운용 Matlab/Simulink 진행료공제계통방진분석,방진결과표명소설계적공제책략능준학실현가사원행사차속요구,액압저능기능유효회수차량제동능,재감속결속시능급시석방저능기능량이절약발동궤소소모적연유,병능구사저능기능량모진시발동궤급시개입보증차량정상행사.연구결과가위정액압전동차량절능감배설계제공삼고.
With the rising concerns about global environmental issues, energy saving in automobiles becomes a very important subject. In recent years, fuel consumption by heavy vehicles grew faster due to the increasing number of heavy vehicles used for transportation. As a result, it is important to save fuel by improving their hydraulic system. The series hydraulic hybrid drive system is more effective than the traditional hydraulic system because of the higher recurperation energy generated by the system. Therefore, in order to reduce energy consumption and exhaust emissions of the heavy vehicle, the series hydraulic hybrid drive system of the heavy vehicles was designed to recover and reuse the energy lost in braking. In this paper, in comparison with the traditional hydraulic drive system, a high-pressure accumulator and a low-pressure accumulator were added in the series hydraulic hybrid drive system. The high-pressure accumulator works as an energy storage system and a power supply, and the low-pressure accumulator works as the tank to supply oil to the system. For an exact description of the working state of the accumulator, the Beattie-Bridgman equation was used to express the pressure of gas in the accumulator. The mathematical models of the pump and the secondary element were established to describe the dynamic working process of them in consideration of the compressibility character of fluid, the pipe pressure loss, the external and internal leakage of the system. According to the higher power density characteristic of hydraulic hybrid system and the frequent starts/stops operation characteristics of the heavy vehicle, an integrated control strategy for the heavy vehicle with series hydraulic hybrid system was proposed. Using the functions of Matlab/Simulink, the simulation block diagram of the control system was set up based on the mathematical model established and the control strategy designed. The control system consisted of a main control unit, a displacement controller of hydraulic pump, a displacement controller of secondary element and an engine control unit. The main control unit as a power management controller used the logic threshold approach to control the dynamic transitions among various driving modes. The displacement controllers of the hydraulic pump and a secondary element used a general PID controller to control the angle of the swash-plate of pump and secondary element for exactly achieving the driver’s target driving speed. The engine control unit controlled the engine throttle position to maximize engine fuel economy and ensure the system was working in at a higher efficiency. The simulation was carried out under the supposed frequent starts/stops driving cycle. Simulation results demonstrated that the heavy vehicle with series hydraulic hybrid drive system effectively recovered and reused the braking energy, and reduced fuel consumption during the vehicle’s travelling. The designed control strategy exactly controlled the vehicle speed in accordance with the driving target speed, reasonably switched among various driving modes of the vehicle and enabled the engine to work in the fuel economy region.