摘 要：由于活塞位移是曲轴转角的非线性函数，在DSP控制器中不易实现在线实时计算，不利于对气门及时、准确地控制。为此，对活塞位移与曲轴转角的非线性关系进行傅里叶展开分析，推出一个简化的位移计算式来替代原有的复杂非线性位移计算，用Matlab对误差进行仿真分析，并成功应用于二冲程电磁气门气动发动机控制系统。实验表明：采用该近似计算，误差可以控制在要求的范围内，发动机能够平稳、可控、高效地运行。
关键词：电磁气门配气；活塞位移计算；傅里叶展开；误差分析
文献标志码：A 文章编号：1674-5124（2015）12-0010-04
Calculation of piston displacement of electromagnetic valve engines
WEI Yili， ZHOU Jinsheng， ZHANG Zilei， TIAN Chunyu
（School of Information Engineering，Inner Mongolia University of Science and Technology，
Baotou 014010，China）
Abstract: How to detect accurate piston positions and control valve on-off in time is one of the most important technical problems to be solved for camless electromagnetic valve engines. It is uneasy to calculate piston displacement online in real time with a digital signal processor due to the nonlinear relationship between piston displacement and crank angle. based on the Fourier expansion， a simplified formula has been deduced to replace the available complex one. Matlab has been used to analyze the calculation errors. This method has been applied to two-stroke electromagnetic valve air-powered engine control systems. Experiments shows that， by using this approximate calculation， the errors can be reduced to a specified range to guarantee that the engine operates in a smooth， controllable and efficient manner.
Keywords: electromagnetic valve valvetrain； piston displacement calculation； Fourier expansion； error analysis
