Method and apparatus for monitoring and determining the functional status of an electromagnetic valve
First Claim
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1. A method of determining a functional status of an electro-mechanical valve having a solenoid and plunger comprising the steps of:
- determining an electro-mechanical switching time, (tems), of a valve based on an electrical characteristic responsive to the solenoid;
determining the (tems) includes determining a beginning and an end of a time window, and wherein determining the beginning of the time window includes the steps of;
evaluating the current supplied to the solenoid over time;
evaluating a valve switching pilot voltage (Vc) over time;
determining when a slope of the (Vc) reaches a predetermined negative value and assigning that time as a switch on time; and
adding a predetermined time value to the switch on time to determine the beginning of the time window;
comparing the (tems) to a tolerance value; and
generating a valve status signal dependant on a result of the comparison.
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Abstract
The present invention provides a method and apparatus for determining the functional status of an electromagnetic valve having a solenoid and plunger including determining the electro-mechanical switching time of a valve based on characteristics of an electrical characteristic responsive to the solenoid; comparing the valve electro-mechanical switching time to a predetermined value; and generating a valve status signal dependant on the results of the comparison.
62 Citations
24 Claims
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1. A method of determining a functional status of an electro-mechanical valve having a solenoid and plunger comprising the steps of:
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determining an electro-mechanical switching time, (tems), of a valve based on an electrical characteristic responsive to the solenoid; determining the (tems) includes determining a beginning and an end of a time window, and wherein determining the beginning of the time window includes the steps of; evaluating the current supplied to the solenoid over time; evaluating a valve switching pilot voltage (Vc) over time; determining when a slope of the (Vc) reaches a predetermined negative value and assigning that time as a switch on time; and adding a predetermined time value to the switch on time to determine the beginning of the time window; comparing the (tems) to a tolerance value; and generating a valve status signal dependant on a result of the comparison. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method of monitoring the functional status of an electro-mechanical valve having a solenoid coil and plunger comprising the steps of:
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energizing the solenoid coil to initiate movement of the solenoid plunger from a first position to a second position; acquiring a signal relating to an electrical characteristic responsive to the solenoid; performing an algorithm on the signal to determine when the plunger reaches the second position; determining a time value based on the plunger movement between the first and second position including the step of staffing a timer upon energizing the solenoid and stopping the timer when the plunger reaches the second position; comparing the time value to a lower and an upper tolerance value; and indicating a functional status of the valve based on the comparison. - View Dependent Claims (18, 19, 20, 21, 22, 23)
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24. A method of determining a functional status of an electromagnetic valve having a solenoid and plunger comprising the steps of:
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determining a time value for the plunger to move between an initial position and a final position based on a first electrical characteristic responsive to the solenoid; comparing the time value to a tolerance range including an upper and lower limit; sensing a second electrical characteristic responsive to the solenoid and determining the tolerance range responsive to the second electrical characteristic; and generating a valve status signal indicating a defective valve if the time value falls outside of the tolerance range.
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Specification