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US 7,609,069 B2Granted
Method to detect shorted solenoid coils
AssigneeKelsey-Hayes Company
InventorsRobert Berg, Richard Graham, III, Christy J. Bose, Scott E. Carpenter
Life of this patent
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Abstract
A method for testing the continuity of a coil that is subjected to a high frequency pulse modulated current that includes sensing a coil voltage, determining a ratio of the sensed coil voltage to the supply voltage and comparing the ratio to a threshold to determine whether the solenoid coil is functional.
Claims11
A method for testing the operation of a hydraulic solenoid valve having a valve solenoid of a vehicle control system,
- wherein the valve solenoid is connected between a power supply and a drain terminal of a Field Effect Transistor (FET), the FET also having a source terminal connected to ground and a gate terminal, the FET being responsive to a voltage applied to the gate terminal to switch between conducting and non-conducting states, wherein:
- the valve is an analog valve operative in a Pulse Width Modulated (PWM) mode in which a PWM voltage is applied to the FET gate with the method including the following steps:
- (a) sensing the supply voltage and the FET drain voltage during one of either the conducting or non-conducting state of the FET;
- (b) calculating the ratio of the FET drain voltage to the supply voltage;
- and
- (c) comparing the resulting ratio to a threshold to determine whether the solenoid coil is operative.
3 more elements
Dependencies are inferred from the claim text.