摘 要：由于活塞位移是曲軸轉角的非線性函數，在DSP控制器中不易實現在線實時計算，不利于對氣門及時、準確地控制。為此，對活塞位移與曲軸轉角的非線性關系進行傅里葉展開分析，推出一個簡化的位移計算式來替代原有的復雜非線性位移計算，用Matlab對誤差進行仿真分析，并成功應用于二沖程電磁氣門氣動發動機控制系統。實驗表明：采用該近似計算，誤差可以控制在要求的范圍內，發動機能夠平穩、可控、高效地運行。
關鍵詞：電磁氣門配氣；活塞位移計算；傅里葉展開；誤差分析
文獻標志碼：A 文章編號：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
