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，
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