Apparatus and method for detecting change of neutral position of valve of electromagnetic valve actuation system, and apparatus and method for controlling the valve

摘要

A valve (1) is urged in the valve-opening direction by an upper spring (24) and in the valve-closing direction by a lower spring (14). The valve (1) is thus urged to a neutral position where the respective urging forces are balanced. The valve (1) is controlled to be released from one of two terminal positions, that is, the full-open position or the full-closed position, and to be attracted to the position from which the valve (1) has been released. The displacement pattern of the valve during this period is sensed by a displacement amount sensor (42), whereby the maximum displacement amount of the valve (1) from that terminal position is measured. The change of the neutral position is detected based on the change of the measured maximum displacement amount with respect to a reference value. <IMAGE>