电控单体泵系统供油特性及其凸轮型线参数化设计

发布时间：2019-01-09 06:11

【摘要】：电控单体泵燃油系统以其高喷射压力、对现有发动机改动小、良好的油品适应性、优良的系统可靠性等优点成为大功率柴油机的理想选择之一。电控单体泵燃油系统的供油特性与其结构及燃油的流动密切相关。供油过程中高压油管内压力波形可以反映出此系统的状态信息。国内柴油机燃油系统正向电控化方向转变。现有加工条件决定了单体泵国产化是现阶段柴油机电控燃油系统国产化切实可行的有效途径。研发具有自主知识产权的电控单体泵迫切需要深入分析电控单体泵结构参数对其供油特性的影响规律。供油凸轮型线设计是电控单体泵燃油系统开发中的关键技术之一。但是，针对电控单体泵系统供油凸轮型线设计的研究极少，需要深入探索其设计方法。因此，本论文以电控单体泵燃油系统供油特性和供油凸轮参数化设计为主线，采用试验、仿真分析及理论分析相结合的技术手段，开展了电控单体泵低速供油特性、中高速工况供油特性、阀杆运动规律、电控单体泵结构参数对供油特性的影响及供油凸轮参数化设计等研究。本文首先搭建了油泵台试验系统，并通过分析得出了单体泵控制阀断电时柱塞速度和柱塞腔内油压的关系，发现此时油压峰值相位会随转速的升高不断后移，提出了一种基于油管压力的单体泵燃油系统喷油特性标定方法。然后，利用该试验系统，进行了单体泵燃油系统的低速供油特性研究，结果表明低速工况时，系统油压建立后存在明显波动，喷油持续期内针阀无法稳定保持开启状态；分析了单体泵的油压波形特点，指出了控制阀开始关闭、控制阀完全关闭、针阀打开反映在油压波形上的具体位置；探索了控制阀杆在高压状态下的运动规律，指出阀杆在初次完全打开、初次完全关闭时会出现反跳，某些工况下，控制阀杆在打开过程中，会出现关闭趋势。之后，分析了BIT电控单体泵的工作原理，指出其结构特点，进行了BIT单体泵的供油特性及一致性试验研究，表明BIT电控单体泵性能、可重复性良好，各泵间油压及喷油量波动不大；建立了BIT单体泵燃油系统仿真模型，标定结果显示该模型达到了合理的精度范围，利用该模型研究了控制阀结构参数、阀座与泵体定位情况、泵体油道及柱塞直径对BIT单体泵供油特性的影响，并提出各结构参数的合理选择范围。随后，从性能、可靠性、稳定性、工艺性角度，总结了供油凸轮主要设计准则；结合由设计准则而来的约束条件，进行了供油凸轮型线的参数化设计方法研究，并建立了供油凸轮型线数学模型，该模型仅包含结构参数和可以反映设计约束的特征参数；分析了各参数对挺柱运动规律和单体泵油压特性的影响，指出最大加速度将会对实现等压喷射有重要影响。最后，进行了供油凸轮型线与电控单体泵的匹配研究，得到了可以实现设计目标的凸轮型线，并校核了其曲率半径，结果表明其在凹弧段可以和滚轮始终接触，在凸弧段，，最小曲率半径在3mm以上。
[Abstract]:The electric control unit pump fuel system is one of the ideal choice for high-power diesel engine with its high injection pressure, small change of existing engine, good oil product adaptability and good system reliability. The oil supply characteristic of the electric control unit pump fuel system is closely related to the structure of the fuel system and the flow of fuel. The pressure waveform in the high-pressure oil pipe during the oil supply can reflect the state information of the system. The fuel system of domestic diesel engine is changing in the direction of electric control. The existing processing conditions decide that the localization of the monomer pump is an effective way for the localization of the electronic control fuel system of the diesel engine at the present stage. The research and development of the electronic control unit pump with the independent intellectual property right urgently needs to analyze the influence of the structure parameters of the electric control unit pump on the oil supply characteristics of the electric control unit. The design of oil-supply cam-type line is one of the key technologies in the development of electric-controlled single-pump fuel system. However, there is little research on the design of the oil supply cam type line for the electric control unit pump system, and the design method needs to be further explored. Therefore, the paper uses the technical means of combination of test, simulation analysis and theoretical analysis to carry out the low-speed oil supply characteristic of the electric control unit pump, the oil supply characteristic of the high-speed working condition and the law of the movement of the valve rod, The influence of the parameters of the electric control unit pump on the oil supply characteristics and the design of the parameters of the oil supply cam and so on. In this paper, the test system of the oil pump station is set up, and the relationship between the plunger speed and the oil pressure in the plunger cavity is obtained through the analysis, and it is found that the peak phase of the oil pressure will follow the increase of the rotation speed. The fuel injection characteristics of a single-pump fuel system based on oil-pipe pressure are proposed. Then, using the test system, the low-speed oil supply characteristic of the single-pump fuel system is studied. The results show that there is a significant fluctuation in the system oil pressure after the low-speed working condition, and the needle valve can not be kept in the open state stably during the injection-sustaining period, and the oil pressure wave of the monomer pump is analyzed. It is pointed out that the control valve is closed, the control valve is completely closed, the needle valve is opened to reflect the specific position on the oil pressure wave form, the movement rule of the control valve rod under the high pressure state is explored, the valve rod is fully opened at the first time, Under working conditions, the control valve stem will be closed during the opening process After that, the working principle of BIT electric control unit pump is analyzed, and its structure is analyzed, and the oil supply characteristics and consistency test of BIT unit pump are studied. It is shown that the performance of BIT electric control unit pump is good, the repeatability is good, and the oil pressure and oil injection among the pumps are good. The simulation model of the fuel system of the BIT monomer pump is established. The calibration results show that the model has a reasonable range of precision. The model is used to study the structure parameters of the control valve, the position of the valve seat and the pump body, the oil channel of the pump body and the diameter of the plunger to supply oil to the BIT unit pump. The influence of the characteristics and the combination of the structural parameters The main design criteria of the oil supply cam are summarized from the viewpoint of performance, reliability, stability and manufacturability. The model of the wheel-type line, which only contains the structural parameters and the characteristic parameters which can reflect the design constraints, analyzes the influence of the parameters on the movement law of the tappet and the pressure characteristics of the pump oil, and points out that the maximum acceleration will be equivalent to the realization of the isobaric In the end, the matching research of the oil supply cam type wire and the electric control unit pump is carried out, the cam type wire with the design goal can be realized, and its radius of curvature is checked. The result shows that it can always be in contact with the roller in the concave arc segment,
【学位授予单位】：北京理工大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TK423

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