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US 6,493,204 B1Granted
Modulated voltage for a solenoid valve
AssigneeKelsey-Hayes Company
InventorsDavid J. Glidden, Daniel D. Moore, Gary P. Whelan
Life of this patent
Estimating the term…
Abstract
A circuit for actuating an ABS solenoid valve coil with a pulse width modulated voltage having a constant frequency and variable duty cycle. The coil current is a function of the duty cycle of the pulse width modulated voltage. By controlling the duty cycle, current saturation of the coil can be avoided to provide for a faster response upon deactuation of the coil. Feedback is included in the circuit to verify correct functioning of electrical components.
Claims17
A control unit for a solenoid valve comprising:
- a power supply;
- a solenoid valve coil have a first end and a second end, said first end of said solenoid valve coil being connected to said power supply;
- an electronic switch having a first terminal connected to said second end of solenoid valve coil, said electronic switch also having a second terminal connected to ground, said electronic switch operable for controlling the flow of an electric current through said solenoid valve coil, said switch further having a control port and being responsive to a control signal applied to said control port to transition between conducting and non-conducting stages;
- a signal generator included within a microprocessor, said microprocessor having an output control port connected to said control port of said electronic switch, said signal generator operative to generate a control signal at said microprocessor output control port, said control signal being a pulse width modulated signal having a variable duty cycle and a constant frequency and said signal generator being operable to generate a first control signal with a predetermined first constant duty cycle sufficient to begin to move an armature of an associated solenoid valve and then to generate a second control signal with a second predetermined constant duty cycle that is less than said first duty cycle and is sufficient to maintain the associated solenoid valve armature in a desired position within the valve;
- and
- a single voltage divider connected across said electronic switch, said voltage divider including a center tap connected to a feedback port of said microprocessor, said microprocessor being responsive to a voltage appearing at said center tap to confirm the operation of said electronic switch.
3 more elements
A method for controlling the current flowing through a solenoid valve coil comprising the steps of:
- (a) providing an electronic switch connected to the valve coil, the switch having a control port and being responsive to a control voltage applied to the control port to change between conducting and non-conducting states;
- (b) applying a pulse width modulated control voltage having a constant frequency and variable duty cycle to the control port of the switch, the voltage having an initial duty cycle having a first predetermined value, the initial duty cycle being sufficient to cause the valve armature to begin to move within the valve from a deactuated position to an actuated position;
- (c) reducing the duty cycle to a second predetermined value upon the valve armature reaching a desired position within the solenoid valve, the second predetermined value being less than the first predetermined value, the second predetermined value being sufficient to provide a coil current which will hold the valve armature in the desired position;
- and
- (d) subsequent to step (c), further reducing the duty cycle to a third predetermined value that is less than the second predetermined value and greater than zero to cause the valve armature to begin to move back toward the deactuated position.
2 more elements
Dependencies are inferred from the claim text.