Electromagnetic valve controller

摘要

An electromagnetic valve controller estimates a dead time based on predetermined parameters. A dead time for the current cycle is determined based on the estimated dead time. The controller measures a dead time in the previous cycle. The controller determines a deviation between the dead time measured in the previous cycle and the dead time estimated in the previous cycle. The deviation is added to the dead time estimated in the current cycle to determine the dead time for the current cycle. The controller further determines a target de-energization timing indicating when to execute a valve timing command, based on predetermined parameters. The dead time determined for the current cycle is offset or subtracted from the target de-energization timing to determine an actual de-energization timing. An electromagnet of the valve is de-energized in accordance with the actual de-energization timing. The accuracy of valve timing is maintained even when some parameters abruptly change due to driving conditions, because the dead time for the current cycle is determined based on the predetermined parameters. The predetermined parameters may include supplied voltage, holding current, engine rotational speed and valve timing.