Hydraulic control unit with ambient temperature compensation during fluid pressure delivery
First Claim
1. A hydraulic control system having a fluid pressure pump with a high pressure outlet side and a low pressure inlet side and having at least one fluid pressure operated member;
- hydraulic pressure distributor conduits in a hydraulic circuit on said low pressure inlet side and between said pump and said pressure operated member;
pressure distributor valve means including one solenoid valve actuator for controlling distribution of fluid pressure to said pressure operated member from said pump outlet and another solenoid valve actuator for controlling distribution of hydraulic fluid to said pump inlet; and
electronic control circuit means for energizing said solenoid valve actuators at an energy level less than a threshold level at which said actuators will be activated to a changed state and for selectively energizing said solenoid valve actuators at an energy level above said threshold level to activate said actuators;
said solenoid valve actuators being disposed in proximity to said hydraulic fluid whereby electrical energy distributed by said electronic control circuit means to said solenoid valve actuators develops heat that increases temperature at the low pressure inlet side of said pump, thereby decreasing hydraulic fluid viscosity when said actuators are energized at said energy level less than said threshold level.
2 Assignments
0 Petitions
Accused Products
Abstract
A hydraulic control unit capable of being used in an automotive vehicle wheel brake system includes a pressure generator such as a master cylinder for a vehicle wheel brake system that includes automatic brake control features. Solenoid-operated valves are used to control the flow of brake fluid to and from the fluid pressure actuators for front and rear brakes. A fluid reservoir is used for storing hydraulic fluid in the hydraulic control unit. A source of electrical energy, such as a solenoid-operated valve, is used to heat the hydraulic fluid to reduce fluid viscosity and thus enhance control unit performance.
99 Citations
4 Claims
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1. A hydraulic control system having a fluid pressure pump with a high pressure outlet side and a low pressure inlet side and having at least one fluid pressure operated member;
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hydraulic pressure distributor conduits in a hydraulic circuit on said low pressure inlet side and between said pump and said pressure operated member; pressure distributor valve means including one solenoid valve actuator for controlling distribution of fluid pressure to said pressure operated member from said pump outlet and another solenoid valve actuator for controlling distribution of hydraulic fluid to said pump inlet; and electronic control circuit means for energizing said solenoid valve actuators at an energy level less than a threshold level at which said actuators will be activated to a changed state and for selectively energizing said solenoid valve actuators at an energy level above said threshold level to activate said actuators; said solenoid valve actuators being disposed in proximity to said hydraulic fluid whereby electrical energy distributed by said electronic control circuit means to said solenoid valve actuators develops heat that increases temperature at the low pressure inlet side of said pump, thereby decreasing hydraulic fluid viscosity when said actuators are energized at said energy level less than said threshold level. - View Dependent Claims (2, 3)
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4. A hydraulic control system having a fluid pressure pump with a high pressure outlet side and a low pressure inlet side and having a fluid pressure operated member;
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hydraulic pressure distributor conduits in a hydraulic circuit in said low pressure inlet side and between said pump and said pressure operated member; pressure distributor valve means including solenoid valve actuators for controlling distribution of fluid pressure to said pressure operated member from said pump outlet and for controlling distribution of fluid from said pressure operated member to said pump inlet; the electric energy supplied to said solenoid valve actuators providing thermal energy for heating hydraulic fluid in said conduits on said low pressure pump inlet side whereby viscosity of the hydraulic fluid on said low pressure pump inlet side is maintained at a temperature level higher than ambient temperature; said control system further including an electronic control circuit means for energizing said solenid valve actuators at an energy level less than a threshold level at which said actuators will be activated to a changed state and for selectively energizing said solenoid valve actuators at an energy level above said threshold level to activate said actuators, said electronic control circuit means including an electronic processor having output driver portions connected to said pressure distributor valve means and to said solenoid valve actuators for heating said hydraulic fluid when said actuators are energized at said energy level less than said threshold level; said electronic processor having memory registers for storing a pre-calculated relationship between hydraulic fluid temperature and actuating current for said valve means, and a logic portion for establishing controlled electrical current delivery to said valve means in accordance with said relationship between operating temperature of said hydraulic fluid and said current.
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Specification