Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B53/00—Component parts, details or accessories not provided for in, or of interest apart from, groups F04B1/00 - F04B23/00 or F04B39/00 - F04B47/00
  • F04B53/10—Valves; Arrangement of valves
  • F04B53/1085—Valves; Arrangement of valves having means for limiting the opening height
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B53/00—Component parts, details or accessories not provided for in, or of interest apart from, groups F04B1/00 - F04B23/00 or F04B39/00 - F04B47/00
  • F04B53/10—Valves; Arrangement of valves
  • F04B53/1002—Ball valves
  • F04B53/101—Ball valves having means for limiting the opening height

Definitions

• the present invention relates to a pump unit for supplying fuel, preferably diesel oil, to an internal combustion engine.
• the present invention relates to a pump unit comprising a pump housing, a piston pump for supplying the fuel to an internal combustion engine, and a gear pump for supplying the fuel to the piston pump.
• the piston pump comprises at least one cylinder, a piston engaged slidably in the cylinder, a passage for the intake of the fuel into the cylinder, a passage for delivering the fuel to the internal combustion engine, and a check valve fitted in the delivery passage to prevent the backflow of the fuel into the cylinder.
• the check valve comprises a substantially spherical plug which is movable between a position in which it closes the delivery passage and a position in which it opens it, and a spring for moving the plug into its closed position and, normally, keeping it there.
• the plug Since the plug is supported solely by the spring, the plug is movable from its closed position, in which it engages an annular spherical seat formed in the delivery passage, to its open position along a path which is not rectilinear and which does not coincide with the longitudinal axis of the delivery passage, the plug therefore being displaced radially and made to rotate by the fuel supplied through the delivery passage. Consequently, the movement of the plug from its open to its closed position also takes place along a non-rectilinear path which does not coincide with the longitudinal axis of the delivery passage, and the plug is therefore kept in rotation by the hydraulic force exerted by the fuel, and is moved radially against a lateral wall of the aforesaid annular spherical seat.
• the centrifugal force generated by the rotation of the plug can be so great, in certain operating conditions, that it retards or even prevents the correct closure of the delivery passage.
• the object of the present invention is to provide a pump unit for supplying fuel, preferably diesel oil, to an internal combustion engine which is free of the drawbacks described above and which is simple and economical to produce.
• a pump unit for supplying fuel, preferably diesel oil, to an internal combustion engine, as claimed in the appended claims.
• the number 1 indicates, as a whole, a pump unit for supplying fuel, preferably diesel oil, to an internal combustion engine (not shown).
• fuel preferably diesel oil
• the pump unit 1 comprises, in the present case, a pump housing 2; a known piston pump, which is not shown, for supplying the fuel to the aforesaid internal combustion engine (not shown); and a known gear pump, which is not shown, for supplying the fuel to the piston pump (not shown).
• the piston pump (not shown) comprises at least one cylinder which is engaged slidably by a piston which can move with a reciprocating rectilinear motion along the cylinder, and which is associated with a passage for the intake of fuel into the cylinder and with a passage 3 for delivering the fuel to the internal combustion engine (not shown).
• the passage 3 has a specified longitudinal axis 4, and comprises a constricted portion 5 communicating with the cylinder of the piston pump (not shown), an enlarged portion 6 communicating with the internal combustion engine (not shown), and an intermediate portion 7, which extends between portions 5 and 6, and forms an annular conical seat 8 which is substantially coaxial with the axis 4.
• the seat 8 forms part of a check valve 9, which is housed in the passage 3 to prevent the backflow of the fuel into the cylinder of the piston pump (not shown), this valve also comprising a substantially spherical plug 10, which is movable between a position in which the passage 3 is closed and a position in which it is open, and being provided with a stop member 11 mounted in the portion 6 to halt the movement of the plug 10 in its open position.
• the member 11 is substantially screw-shaped and comprises a head 12 screwed into the pump housing 2 and a tubular shank 13, which extends into the portion 6 coaxially with the axis 4, and has an outside diameter which is smaller than the inside diameter of the portion 6.
• the free end of the shank 13 facing the plug 10 is axially open and forms an annular conical seat 14 for halting the movement of the plug 10 in its open position.
• the shank 13 forms, in combination with the portion 6, an annular chamber 15 which is substantially coaxial with the axis 4, and also has an internal passage 16 which is coaxial with the axis 4, and comprises an enlarged portion 17 facing the plug 10 and a constricted portion 18 facing the head 12.
• the portion 17 houses within it a spring 19, mounted coaxially with the axis 4, for moving the plug 10 into its closed position and normally keeping it there, and communicates with the chamber 15 through a plurality of holes 20 which are uniformly distributed about the axis 4 and which are formed through the shank 13 transversely with respect to the axis 4; and the portion 18 communicates with an annular manifold 21 formed in the pump housing 2 coaxially with the axis 4 through a plurality of holes 22, which are uniformly distributed about the axis 4, and which are formed through the shank 13 transversely with respect to the axis 4.
• the portion 6 and the shank 13 are also coupled together in a fluid-tight way by the interposition of an annular seal 23, in the present case an O-ring, mounted coaxially with the axis 4 in an intermediate point of the shank 13 between the holes 20 and 22.
• an annular seal 23 in the present case an O-ring, mounted coaxially with the axis 4 in an intermediate point of the shank 13 between the holes 20 and 22.
• the plug 10 is moved, by the fuel supplied by the piston pump (not shown) along the passage 3, to the position in which it opens the passage 3, thus enabling the fuel to flow, in succession, through the intermediate portion 7, along the chamber 15, through the holes 20, along the passage 16, through the holes 22, and into the manifold 21.
• the diameter of the plug 10 and the inside diameter of the portion 17 are controlled selectively in such a way that the force exerted on the plug 10 by the fuel contained in the passage 3 is greater than the sum of the forces exerted on the plug 10 by the spring 19 and by the fuel contained in the passage 16, and since the supply of the fuel along the chamber 15 and through the holes 20 causes a pressure drop in the fuel, resulting in a lower pressure in the passage 16 than in the passage 3, the plug 10 is moved along a rectilinear path along the axis 4 in such a way that it engages the seat 14, and is substantially held in the seat 14 throughout the delivery phase of the piston pump (not shown) without the possibility of moving axially and/or radially.
• the plug 10 is moved along a substantially rectilinear path along the axis 4 by the force of the spring 19 and the fuel contained in the passage 16, in such a way that it engages the seat 8 and closes the passage 3 relatively quickly.
• the spring 19 is omitted, and the plug 10 is closed solely by the force of the fuel contained in the passage 16.
• the annular seal 23 is omitted and the shank 13 is made in such a way that it comprises a constricted end portion, which is provided with the holes 20, and which has an outside diameter smaller than the diameter of the portion 6, and an enlarged intermediate portion, which extends between the holes 20 and 22, has an outside diameter substantially equal to the diameter of the portion 6, enables the fuel to be diverted through the holes 20 so as to provide the desired pressure drop in the fuel in the passage 16, and simultaneously prevents the fuel from flowing directly into the manifold 21 along the chamber 15.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Fuel-Injection Apparatus (AREA)
• Lubrication Of Internal Combustion Engines (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Priority Applications (5)

Applications Claiming Priority (2)

Publications (2)

Family

ID=42272163

Family Applications (1)

Country Status (6)

Cited By (2)

Families Citing this family (3)

Family Cites Families (12)

• 2009
  • 2009-11-06 IT IT001948A patent/ITMI20091948A1/it unknown
• 2010
  • 2010-10-12 IN IN1494DEN2012 patent/IN2012DN01494A/en unknown
  • 2010-10-12 RU RU2012123138/06A patent/RU2555097C2/ru not_active IP Right Cessation
  • 2010-10-12 EP EP10763714.2A patent/EP2496837B1/en not_active Not-in-force
  • 2010-10-12 CN CN201080049784.7A patent/CN102597521B/zh not_active Expired - Fee Related
  • 2010-10-12 WO PCT/EP2010/065272 patent/WO2011054632A2/en active Application Filing

Non-Patent Citations (1)

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