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US 5,404,303 AGranted
Solenoid current driver circuit
AssigneeAlliedSignal Truke Brake Systems
InventorsTamas I. Pattantyus, Steven J. Griggs
Life of this patent
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AssigneeAlliedSignal Truke Brake Systems
InventorsTamas I. Pattantyus, Steven J. Griggs
Estimating the term…
A brake pressure control mechanism for establishing a pressure level in a brake actuator includes a valve controlled by the current in a solenoid coil. The current in the coil is controlled in a first mode by switching the current in the coil off and on and allowing the current to increase and decay in the normal manner. However, when a fast decrease in brake pressure is demanded, the fly-back voltage across the coil is allowed to rapidly increase to a level greater than and in opposition to the voltage applied to the coil, thereby quickly driving the current lower. Current is driven to zero in the case of a fast brake pressure decay being demanded by the adaptive braking system or when the vehicle operator releases the brakes. When the error signal demands a fast decay, the fast decay mode is initiated and then returned to the normal control when the error between the demanded braking pressure and the pressure corresponding to the current of the coil is back within predetermined limits.
Brake pressure control mechanism for establishing a pressure level in a brake actuator, said mechanism including a valve controlled by a coil, actuation means for operating said valve, said actuation means including a circuit means for connecting a voltage source to said coil, said circuit means comprising:
Brake pressure control mechanism for establishing a pressure level in a brake actuator, said mechanism including a valve controlled by a coil, actuation means for operating said valve, said actuation means including circuit means for connecting a voltage source to said coil, said circuit means including first control means for controlling electrical current in said coil to initiate a normal current decay mode when the required rate of current decay does not exceed a predetermined rate, and second control means for initiating a fast current decay mode when the actuation means demands a decrease in current through said coil in excess of said predetermined rate;
Brake pressure control mechanism for establishing a pressure level in a brake actuator, said mechanism including a valve controlled by a coil, actuation means for operating said valve, said actuation means including circuit means for connecting a voltage source to said coil, said circuit means including a current sensor for generating a current feedback signal which varies in accordance with the current flow through the coil, said actuation means including means for comparing said current feedback signal and a current request signal representing a requested brake pressure level and for generating a pressure decrease error signal when said current feedback signal exceed the current request signal by more than a preestablished amount, said first and second control means being responsive to said error signal for initiating said normal decay mode when the error signal is less than a predetermined level and for initiating said fast current decay mode when the error signal is greater than the predetermined level.
Dependencies are inferred from the claim text.