| 摘要 |
<p>A method and apparatus for measuring hydraulic pressure in a solenoid valve (102, 104) includes coupling the solenoid valve (102, 104) with a voltage source and monitoring the input current rise characteristic as the solenoid valve (102, 104) moves between the open and closed positions. The rise characteristic indicates the amount of current needed to move the solenoid valve (102, 104) and changes when the solenoid (102, 104) changes positions. The current levels in the characteristic are taken at two different time periods and compared to determine whether the solenoid (102, 104) has shifted positions by the second time period. Because a greater amount of current is required to move the solenoid valve (102, 104) if the hydraulic pressure is high, the rise characteristic will change sooner if the pressure is low and later if the pressure is high. The hydraulic pressure can therefore be determined by comparing the two current levels and correlating them with pressure values. As a result, hydraulic pressure can be measured and monitored without requiring attachment of a separate pressure sensor on the solenoid valve (102, 104). <IMAGE></p> |
