Variable-flow high pressure pump

Abstract

A variable-flow high-pressure pump comprising at least one piston mounted to slide axially and in a leak-tight manner within a cylindrical cavity obtained in the body of the pump so as to define a variable-volume pumping chamber adapted to be filled with a fluid, and an intake valve and a delivery valve adapted to enable the one-way flow of the fluid respectively into and out of the pumping chamber, the intake valve being formed by a non-return valve comprising a shutter body which can move to and from a closed position in which it prevents the passage of the fluid via the valve, and an elastic member adapted to maintain the shutter body in the above-mentioned closed position, the high-pressure pump further comprising a hydraulic piston selectively adapted to distance the shutter body from the closed position by overcoming the resistance of the elastic member so as to enable the fluid also to flow freely via the valve in a direction opposite to the normal direction.

1 . A variable-flow high-pressure pump ( 1 ) comprising at least one pumping piston ( 4 ) mounted to slide axially and in a leak-tight manner within a cylindrical cavity ( 5 ) obtained in the body ( 6 ) of the pump so as to define a variable-volume pumping chamber ( 7 ) adapted to be filled with a generic fluid, at least one intake valve ( 9 ) and a delivery valve ( 8 ) adapted to enable the one-way flow of the fluid respectively into and out of the pumping chamber ( 7 ), the intake valve ( 9 ) being formed by a non-return valve ( 9 ) comprising a shutter body ( 10 ) which can move to and from a closed position in which it prevents the passage of the fluid via this valve, the high-pressure pump ( 1 ) further comprising flow regulation means ( 13 ) adapted to interfere with the normal operation of the intake valve ( 9 ) in order to enable the fluid also to flow freely via the valve in a direction opposite to the normal direction, the high-pressure pump ( 1 ) being characterized in that the flow regulation means ( 13 ) comprise a hydraulic piston ( 14 ) selectively adapted to prevent the shutter body ( 10 ) from returning to the closed position.  
     
     
         2 . A high-pressure pump as claimed in  claim 1 , characterized in that the hydraulic fluid ( 14 ) is supplied from the pressurized fluid supplied as input to the intake inlet ( 1   b ) of this pump.  
     
     
         3 . A high-pressure pump as claimed in  claim 2 , characterized in that the flow regulation means ( 13 ) comprise an electrically actuated exhaust valve ( 15 ), which is selectively adapted to cause a pressure drop in the fluid that is supplied to the hydraulic piston ( 14 ), so as to block the action of this hydraulic piston ( 14 ).  
     
     
         4 . A high-pressure pump as claimed in  claim 3 , characterized in that the flow regulation means ( 13 ) comprise an electronic control unit ( 16 ) adapted to drive the exhaust valve ( 15 ) so as to control the time interval in which the intake valve ( 9 ) is disabled.  
     
     
         5 . A high-pressure pump as claimed in  claim 1 , characterized in that the hydraulic piston ( 14 ) is a single-acting hydraulic piston.  
     
     
         6 . A high-pressure pump as claimed in  claim 1 , characterized in that the intake valve ( 9 ) is formed by a non-return valve ( 9 ) which comprises an elastic member ( 12 ) adapted to maintain the shutter body ( 10 ) in the closed position, the hydraulic piston ( 14 ) being adapted to prevent the shutter body ( 10 ) from returning to its closed position, overcoming the resistance of the elastic member ( 12 ).  
     
     
         7 . A system for the supply of fuel to an internal combustion engine, characterized in that it comprises a high-pressure pump ( 1 ) as claimed in  claim 1.