配气机构参数对汽油机低速扭矩影响的研究

发布时间：2018-01-17 02:11

本文关键词：配气机构参数对汽油机低速扭矩影响的研究　出处：《吉林大学》2016年硕士论文　论文类型：学位论文

【摘要】：现代城市交通状况愈加拥挤,由此城市汽车绝大部分时间采用中低转速行驶。为保证汽车行驶过程中能获得充足的动力输出,提升发动机低速扭矩显得格外重要。本文主要通过对某2.0L自然吸气的汽油机设计新的配气相位,并设计出合理的凸轮型线来实现提升其低速扭矩的目标。本论文首先运用AVL Timing Drive凸轮设计软件针对目标发动机进行凸轮型线的设计,分析了配气相位及凸轮型线缓冲段参数工作段参数对凸轮型线的曲率半径、丰满系数和加速度的影响规律。得到了凸轮型线设计中各参数选取依据和范围,对丰满系数、曲率半径和加速度的影响,例如在合适的缓冲段速度范围内,随缓冲段的速度升高,凸轮型线的丰满系数和最小曲率半径都呈上升趋势,且正加速度峰值减小等。同时利用GT/Power软件建立目标2.0L自然吸气汽油机仿真模型,将配气机构参数合理导入并对进气系统进行合理划分,建立合理的仿真模型。并将扭矩与油耗的仿真结果与实验值进行对比,误差控制在5%以内,验证所建模型的正确性。最后,再次利用AVL Timing Drive凸轮设计软件针对目标发动机进行各组配气相位的凸轮型线设计,探究配气相位等参数对发动机低速扭矩的影响规律。通过设计得到适合不同转速的提高扭矩的方案,最后选择提高低速段扭矩范围且合理的凸轮型线进行优化设计。最终,将优化的凸轮型线参数导入到GT/Power进行整机模拟计算,低速工况点的扭矩提升幅度都达到5.5%左右,达到我们的目标要求。
[Abstract]:Modern urban traffic is becoming more and more congested, so most of the time urban cars use medium and low speed. In order to ensure that the vehicle can get sufficient power output in the course of driving. It is very important to lift the engine torque at low speed. In this paper, a new valve phase is designed for a 2.0L naturally aspirated gasoline engine. And a reasonable cam profile is designed to achieve the goal of improving its low speed torque. Firstly, AVL Timing is used in this paper. The Drive cam design software is used to design the cam profile for the target engine. The effects of the phase of valve distribution and the working parameters of the buffer section of the cam profile on the curvature radius, the fullness coefficient and the acceleration of the cam profile are analyzed, and the selection basis and range of the parameters in the design of the cam profile are obtained. The effects on the full coefficient, radius of curvature and acceleration, such as the increase of the velocity of the buffer section, the fullness coefficient and the minimum radius of curvature of the cam profile show an upward trend. At the same time, the simulation model of 2.0L natural inspiratory gasoline engine is established by using GT/Power software, and the parameters of the valve train mechanism are reasonably imported and the intake system is reasonably divided. The simulation results of torque and fuel consumption are compared with the experimental data, and the error is controlled within 5% to verify the correctness of the model. Thirdly, the cam profile of each valve phase is designed with AVL Timing Drive cam design software for the target engine. The effect of the parameters such as valve phase on the engine torque at low speed is studied. The scheme of improving torque suitable for different speed is obtained by design. Finally, the optimized cam profile is selected to improve the torque range of the low speed section and the reasonable cam profile is designed. Finally, the optimized parameters of the cam profile are imported into GT/Power to simulate the whole machine. Low-speed operating point torque up to about 5.5%, to meet our target requirements.
【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】：U464.171

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