变量机油泵一维流动分析及优化

发布时间：2018-11-18 21:02

【摘要】：发动机润滑用变量机油泵是在定量机油泵基础上发展而来的新技术,其排量随发动机工况改变,可降低能耗2%至3%。本文以电磁开关齿轮式变量机油泵为研究对象,建立其数学模型及一维流动模型并以试验验证,并对油泵内流体运动特性进行分析并优化。首先,在分析齿轮式变量机油泵工作原理和数学模型的基础上,建立齿轮泵及变量机油泵一维仿真模型。通过两种方法模拟齿轮泵内各部分容积及容积间通流面的变化,一是CAD测量法,二是搭建齿轮泵流量公式法。将齿轮泵与恒压阀、电磁阀等连接起来建立完整的变量机油泵模型,并通过台架试验验证模型精度。然后,仿真分析机油泵流体特性及控制机构的运动特性。主要包括滤清器后压力流量变化;恒压阀运动特性及其结构参数对油泵特性的影响;根据主从动齿轮啮合宽度计算不同转速下的容积效率;分析滤清器及发动机阻尼变化对油泵性能的影响等。研究表明,变量机油泵在发动机启动阶段实质为定量泵,当转速达到1462r/min时进入变量阶段,恒压阀控制滤清器后的油压相对稳定,其结构参数决定着油压大小。最后,通过分析油泵特性确定优化目标并对其优化。在油泵油压及流量设计范围内,以减小稳态时的油压波动及电磁阀关闭时的冲击油压为优化目标,选定优化变量并确定约束范围,利用NLPQL算法对齿轮及恒压阀参数进行优化。优化后的低压稳态压力波动减小25.88%,高压稳态波动减小25.91%,冲击油压明显减弱。本文旨在通过建模及试验分析电磁开关齿轮式变量机油泵特性并对其进行优化,可为油泵概念设计及改进更改提供技术支持。另外,本文所用变量齿轮泵的一维建模方法对其他变量容积泵建模有一定参考价值。
[Abstract]:Variable engine oil pump for engine lubrication is a new technology developed on the basis of quantitative engine oil pump. Its displacement can reduce energy consumption by 2% to 3% with the change of engine working condition. In this paper, the mathematical model and one-dimensional flow model of electromagnetic switched gear variable engine oil pump are established and verified by experiments, and the fluid motion characteristics in oil pump are analyzed and optimized. Firstly, on the basis of analyzing the working principle and mathematical model of gear variable engine oil pump, the one-dimensional simulation model of gear pump and variable engine oil pump is established. Two methods are used to simulate the change of volume and flow surface between different parts of gear pump, one is CAD measurement method, the other is the method of setting up the flow formula of gear pump. The gear pump is connected with constant pressure valve and solenoid valve to establish a complete model of variable engine oil pump, and the accuracy of the model is verified by bench test. Then, the fluid characteristics of the oil pump and the motion characteristics of the control mechanism are analyzed by simulation. It mainly includes the change of pressure and flow after filter, the effect of constant pressure valve movement and its structure parameters on oil pump characteristics, the calculation of volumetric efficiency under different rotational speeds according to the meshing width of main driven gear. The influence of filter and engine damping on the performance of oil pump is analyzed. The results show that the variable engine oil pump is a quantitative pump in the starting stage of the engine. When the rotational speed reaches 1462r/min, the oil pressure is relatively stable after the constant pressure valve controls the filter, and its structure parameters determine the oil pressure. Finally, the optimization objective is determined by analyzing the characteristics of the oil pump and its optimization. In the design range of oil pressure and flow of oil pump, the optimization objective is to reduce the fluctuation of oil pressure in steady state and the impact oil pressure when solenoid valve is closed. The optimization variables are selected and the constraint range is determined. The parameters of gear and constant pressure valve are optimized by NLPQL algorithm. After optimization, the fluctuation of low pressure steady state pressure and high pressure steady state pressure are reduced by 25.88 and 25.91 respectively, and the impact oil pressure is obviously weakened. The purpose of this paper is to analyze and optimize the characteristics of electromagnetic switched gear variable engine oil pump by modeling and testing, which can provide technical support for the conceptual design and improvement of oil pump. In addition, the one-dimensional modeling method of variable gear pump used in this paper has certain reference value for other variable volume pump modeling.
【学位授予单位】：上海工程技术大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U464.137.1

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