Active pressure relief valve system and method

Abstract

An active pressure relief valve system and method for lubricating an internal combustion engine includes a reservoir, a pump for pumping fluid from the reservoir through the internal combustion engine, and an active relief valve fluidly disposed downstream from the pump for both variably adjusting pressure of the fluid within the internal combustion engine and limiting the pressure of the fluid within the internal combustion engine to a maximum pressure threshold. The active relief valve is configured to variably and electronically adjust the pressure of the fluid within the internal combustion engine when commanded by a controller, and further configured to mechanically limit the pressure of the fluid within the internal combustion engine to a maximum pressure threshold.

1 . An active pressure relief valve system for lubricating an internal combustion engine, comprising:
 a reservoir;   a pump for pumping fluid from the reservoir through the internal combustion engine; and   an active relief valve fluidly disposed downstream from the pump for both variably adjusting pressure of the fluid within the internal combustion engine and limiting the pressure of the fluid within the internal combustion engine to a maximum pressure threshold, the active relief valve configured to variably and electronically adjust the pressure of the fluid within the internal combustion engine when commanded by a controller and further configured to mechanically limit the pressure of the fluid within the internal combustion engine to the maximum pressure threshold.   
     
     
         2 . The active pressure relief valve system of  claim 1  wherein the active relief valve includes:
 an actuator that variably and electronically adjusts the pressure of the fluid within the internal combustion engine via rotational movement; and 
 a piston movable against urging of a spring that mechanically limits the pressure of the fluid within the internal combustion engine via axial movement. 
 
     
     
         3 . The active pressure relief valve system of  claim 2  wherein the active relief valve is disposed within only a single relief bore defined within the internal combustion engine. 
     
     
         4 . The active pressure relief valve system of  claim 2  wherein the piston includes at least one axial throughole and the active relief valve includes a rotatable member variably and rotatably movable between a first position and a second position for variably opening or closing the at least one axial throughole, the first position allowing relatively more fluid flow through the at least one axial throughole than the second position. 
     
     
         5 . The active pressure relief valve system of  claim 4  wherein the actuator is a motor that rotatably moves the rotatable member under command by the controller. 
     
     
         6 . The active pressure relief valve system of  claim 5  wherein the rotatable member is connected to the motor by the spring such that rotation of the spring by the motor causes rotation of the rotatable member relative to the piston. 
     
     
         7 . The active pressure relief valve system of  claim 6  wherein one of the piston and a wall of the internal combustion engine defining a relief bore in which the active relief valve is disposed includes a protrusion and the other of the piston and the wall includes an aperture in which the protrusion is received to prevent relative rotation between the wall and the piston. 
     
     
         8 . The active pressure relief valve system of  claim 4  wherein the motor includes a torsion spring that urges the rotatable member toward the second position such that, when the controller is not commanding the pressure relief valve, the rotatable member moves toward the second position. 
     
     
         9 . The active pressure relief valve system of  claim 1  further including:
 the controller that commands the active relief valve to variably adjust the pressure of the fluid within the internal combustion engine; and 
 a pressure sensor operatively connected to the controller that senses the pressure of the fluid and sends a signal to the controller that is indicative of the pressure sensed, and wherein the controller variably adjusts the pressure of the fluid based on the signal from the pressure sensor. 
 
     
     
         10 . The active pressure relief valve system of  claim 1  further including:
 a relief bore defined in the internal combustion engine in which the active relief valve is received; 
 a first discharge passage fluidly connected to the relief bore for discharging the fluid passing through the relief valve to variably adjust the pressure of the fluid of the internal combustion engine; and 
 a second discharge passage fluidly connected to the relief bore for discharging the fluid passing through the relief valve to limit the pressure of the fluid in the internal combustion engine to the maximum pressure threshold. 
 
     
     
         11 . The active pressure relief valve system of  claim 1  wherein an indicator is operatively connected to the controller, the indicator activated when there is a failure of the active relief valve. 
     
     
         12 . An active oil pressure relief valve for a vehicle, comprising:
 a valve assembly disposed within a relief bore, the relief bore fluidly connected downstream to a pump for pumping fluid from a reservoir and arranged to selectively return the fluid to the reservoir to variably control a pressure of the fluid and to limit a maximum pressure of the fluid;   an actuator of the valve assembly rotatably movable to variably control the pressure of the fluid; and   a piston of the valve assembly axially movable to limit the maximum pressure of the fluid, the piston axially displaced when the fluid reaches the maximum pressure and thereby passing through the valve assembly back to the reservoir.   
     
     
         13 . The active pressure relief valve of  claim 12  wherein the valve assembly includes a spring for urging the piston toward a closed position, the piston movable axially against the urging of the spring when the pressure of the fluid reaches the maximum pressure. 
     
     
         14 . The active pressure relief valve of  claim 13  wherein the valve assembly includes a rotatable member that is rotatable by the actuator for selectively opening and closing at least one passage defined through the piston, and wherein a degree of rotation of the rotatable member by the actuator corresponds to a degree of closure of the at least one passage by the rotatable member. 
     
     
         15 . The active pressure relief valve of  claim 14  wherein the piston includes a radial wall portion through which the at least one passage is defined and a cylindrical sleeve wall portion depending from the radial wall portion, and wherein the rotatable member is cooperatively received radially and axially within the cylindrical sleeve wall portion. 
     
     
         16 . The active pressure relief valve of  claim 14  wherein the at least one passage is a plurality of axial througholes defined through the piston and the rotatable member includes a corresponding plurality of axial througholes defined therethrough, the rotatable member rotatable by the actuator from a first rotatable position wherein the plurality of axial througholes and the corresponding plurality of axial througholes are misaligned to inhibit flow through the at least one passage and a second rotatable position wherein the plurality of axial througholes and the corresponding plurality of axial througholes are in registry with one another. 
     
     
         17 . The active pressure relief valve of  claim 13  wherein the actuator is a motor having an output shaft connected to the rotatable member by the spring for transferring rotation movement of the output shaft to the rotatable member. 
     
     
         18 . The active pressure relief valve of  claim 12  further including a controller operatively connected to the actuator for control thereof based on a sensed pressure of the fluid. 
     
     
         19 . An active pressure relief valve method for lubricating an internal combustion engine, comprising:
 providing an active relief valve fluidly disposed downstream from a pump fluidly connected to a fluid reservoir for both variably adjusting pressure of a fluid pumped by the pump within the internal combustion engine and limiting the pressure of the fluid within the internal combustion engine to a maximum pressure threshold;   variably and electronically adjusting the pressure of the fluid within the internal combustion engine via a controller operatively connected to the active relief valve; and   passively and mechanically limiting the pressure of the fluid within the internal combustion engine to a maximum pressure threshold.   
     
     
         20 . The method of  claim 19  wherein variably and electronically adjusting the pressure of the fluid includes controlling an actuator to rotatably move the active relief valve, and passively and mechanically limiting the pressure of the fluid includes urging a piston via a spring toward a closed position for inhibiting passage of the fluid until the pressure reaches the maximum pressure threshold.