发动机进气控制系统开发及试验研究

发布时间：2017-12-27 02:19

本文关键词：发动机进气控制系统开发及试验研究　出处：《吉林大学》2016年硕士论文　论文类型：学位论文

【摘要】：随着能源危机和环境污染问题的日益突出,各国开始探究不同形式的节能减排方式,其中加强燃料的高效利用和降低排放污染变得更加迫切。相关研究表明,进气相位控制对发动机燃烧过程优化和发动机污染物控制至关重要。尤其是可变气门正时技术和可变气门升程技术的运用,对于提高发动机进气量、提高燃烧热效率以及控制发动机内部EGR率起到了明显作用。本研究设计了一款基于液压控制的可变气门配气机构。通过利用GT-power软件对某四缸柴油机进行仿真,研究不同进气提前角、不同进气迟闭角和不同气门升程条件下发动机的性能。模拟结果表明,不同转速下,发动机所需要的最适宜气门状态是不同的。该模拟明确了所设计机构的必要性和使用价值。针对该电控液压可变气门正时机构进行了整体规划并进行了相关结构设计。通过液压仿真软件AMEsim对机构进行了模拟。重点对系统液压压力、节流阀参数、弹簧刚度、弹簧预紧力和大柱塞外径几个参数进行仿真过程模拟。结果表明:系统液压压力、弹簧钢度系数和弹簧预紧力对气门运动的升程变化影响较大,并呈现一定的变化规律。节流阀参数和大柱塞外径则对气门的打开落座速度影响较大。本文所设计机构应用于四气门发动机,相对两气门结构更加紧凑复杂,但是可以保证更好的进气量。同时电磁液压气门正时机构可以实现四气门的独立控制,可以优化进气条件,为实现缸内活化分层提供了条件。本研究建立了电控液压可变气门正时机构试验平台,并对装置进行了运行试验。利用数据采集卡对机构运动数据和控制数据进行了采集。试验结果验证了所设计机构基本实现了与仿真模拟结果相同的运动曲线,且具有较好的可重复性。对机构的动态响应进行了分析,结果表明,在相同液压压力条件下,气门开启和关闭的动态响应时间服从正态分布规律。探究了气门打开和关闭所需响应时间与系统液压压力的相关关系。统计结果发现,随着系统液压压力的增加,气门打开延迟时间逐渐增加,气门关闭响应时间逐渐缩短。该研究为气门的前馈控制提供了可能。同时试验得到了气门升程随系统液压压力的对应关系,整体上气门升程在8MPa至12MPa内实现了升程5mm至9mm的变化,实现了可变气门升程的功能。
[Abstract]:With the increasingly prominent problem of energy crisis and environmental pollution, various countries begin to explore different ways of energy conservation and emission reduction. Strengthening fuel efficient utilization and reducing emission pollution become more urgent. The related research shows that the intake phase control is very important to the optimization of engine combustion process and the control of the engine contaminants. In particular, the application of variable valve timing technology and variable valve lift technology has played a significant role in improving engine intake volume, improving combustion efficiency and controlling the internal EGR rate of engine. A variable valve valve based on hydraulic control is designed in this study. By using GT-power software, a four cylinder diesel engine is simulated, and the performance of the engine is studied under different intake angle, intake delay angle and valve lift. The simulation results show that the optimal valve condition is different for the engine at different speeds. The simulation clarifies the necessity and the use value of the designed organization. The overall planning of the electronically controlled hydraulic variable valve timing mechanism was carried out and the related structure was designed. The mechanism was simulated by the hydraulic simulation software AMEsim. Focus on the system of hydraulic pressure, throttle valve parameters, spring stiffness, spring preload and the plunger diameter of several parameters to simulate the process of. The results show that the hydraulic pressure of the system, the coefficient of spring steel degree and the pre tightening force of spring have great influence on the lift of the valve movement, and present a certain change law. The throttle valve parameters and outer diameter of column valve open seating velocity has great influence. The design of this mechanism is applied in four valve engine, two valve structure is more compact and relatively complex, but can ensure better air intake. At the same time, the electromagnetic hydraulic valve timing mechanism can realize the independent control of the four valve. It can optimize the intake conditions and provide the conditions for the realization of the activation and stratification in the cylinder. The test platform of the electronically controlled hydraulic variable valve positive timing mechanism is set up in this study, and the operation test of the device is carried out. The data acquisition card is used to collect the motion data and control data of the mechanism. The test results verify that the designed mechanism has basically realized the same motion curve as the simulation result, and has good repeatability. The dynamic response of the mechanism is analyzed. The results show that under the same hydraulic pressure, the dynamic response time of valve opening and closing is subject to normal distribution. The relationship between the response time required for opening and closing the valve and the hydraulic pressure of the system is explored. The results show that with the increase of hydraulic pressure of the system, the delay time of valve opening increases gradually and the response time of valve closing gradually shortens. The study provides a possibility for the feedforward control of the valve. At the same time, the relationship between valve lift and system hydraulic pressure is obtained. On the whole, valve lift is changed from 5mm to 9mm at 8MPa to 12MPa, and variable valve lift function is achieved.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TK403

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