Oil pump control valve spool with pilot pressure relief valve
AssigneeBorgWarner Inc.
InventorDouglas G. Hunter
Life of this patent
Estimating the term…
Abstract
A valve spool (70) for an oil pump assembly (10) that includes a pilot pressure relief valve (80) to provide pilot pressure relief that increases the stability of the pump assembly (10) and eliminates the delay between the change in the discharge pressure and the associated response to the pilot pressure. The valve spool (70) operates in response to the pilot pressure to increase or decrease the pump discharge pressure during vehicle operation. A chamber (72) within the valve spool (70) is in fluid communication with the discharge flow and pressure at one end and the pilot pressure at the other end. When the pilot pressure exceeds the discharge pressure, the relief valve (80) opens, allowing the discharge pressure and the pilot pressure to equalize.
Claims21
A pump assembly for delivering lubricant flow, said pump assembly comprising:
- a housing, said housing including a pump inlet, a pump discharge outlet, and a pilot pressure inlet, said pilot pressure inlet taken from a point remote from said pump discharge outlet;
- and
- a control valve positioned within the housing, said control valve including a first end and a second end, said first end of the control valve being in fluid communication with the pilot pressure inlet, said control valve further including an internal chamber and a pilot pressure check valve positioned within the chamber, said chamber being in fluid communication with the pilot pressure inlet and the discharge outlet and said check valve providing pilot pressure relief to equalize the pilot pressure and the discharge pressure.
An engine oil pump assembly for controlling the flow of engine oil, said pump assembly comprising:
- a housing, said housing including a pump inlet, a pilot pressure inlet, and a pump discharge outlet, said pump inlet being in fluid communication with an oil source, said pilot pressure inlet and said discharge outlet being in fluid communication with an engine;
- a first pump positioned within the housing and being in fluid communication with the pump inlet, said first pump providing a first stage discharge flow to the discharge outlet;
- and
- a valve spool positioned within the housing, said valve spool including a first end and a second end, said first end of the valve spool being in fluid communication with the pilot pressure inlet and said second end of the valve spool being in contact with a biasing spring seated within the housing, said spring biasing the valve spool to a first valve position, said valve spool further including an internal chamber and a pilot pressure relief valve positioned within the chamber, said chamber being in fluid communication with the pilot pressure inlet and the discharge outlet, said pilot pressure relief valve providing pilot pressure relief.
A method of equalizing the pressure between a pilot pressure and pump discharge pressure in a pump assembly, said method comprising the steps of:
- providing a pump discharge pressure from the pump assembly;
- providing a pilot pressure to the pump assembly, which is taken from a point remote from said pump discharge pressure;
- applying the discharge pressure and the pilot pressure to a movable control valve positioned within the assembly;
- and
- equalizing the discharge pressure and the pilot pressure through a chamber (72) extending through the control valve.
Dependencies are inferred from the claim text.