Fuel injection pump

• US 4,940,036 A
• Filed: 02/13/1989
• Issued: 07/10/1990
• Est. Priority Date: 06/13/1987
• Status: Expired due to Term

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Duplat, Gerard
• Primary Examiner(s): Miller, Carl Stuart
• Application Number:
  US07/315,895
• Time in Patent Office: 512 Days
• Field of Search: 123/506, 123/450, 123/458, 417/462
• US Class Current: 123/506
• CPC Class Codes: F02M 41/06 the distributor rotating
• CPC Class Codes: F02M 59/366 Valves being actuated electrically

Abstract

A distribution fuel injection pump for delivering fuel to injection nozzles of an internal combustion engine, said distribution fuel injection pump comprising a pump working space communicating with the inlet connected with a fluid source and an outlet connected with the injection nozzles, at least one pump plunger defining at least partially said pump working space, a distributor piston having a distributor bore communicating the pump working space with the outlet and a relief bore communicating the a relief space, and a control valve for controlling fluid flow through the outlet, said control valve including a valve element for controlling fuel flow between distribution bore and the relief bore of the distributor piston.

Claims

1. A distribution fuel injection pump for delivering fuel to a plurality of injection nozzles of an internal combustion engine, said distribution fuel injection pump comprising an inlet communicating with a source of fuel;

an outlet for delivering fuel to the injection nozzles;

a pump working space communicating with said inlet and outlet;

at least one pump plunger defining at least partially said pump working space;

a rotatable distributor piston having a distributor bore communicating said pump working space with said outlet; and

a control valve for controlling fluid flow through said outlet, said distributor piston comprising a relief bore communicating with a relief space, said control valve comprising a valve opening located in said distributor piston and connecting said distribution and relief bores, a valve member located in said distributor piston for controlling fluid flow through said valve opening to thereby control the fluid flow between said distribution bore and said relief bore, and an electromagnet for controlling movement of said valve member;

said distributor piston comprising an axial guide bore, said valve member being formed as a valve needle having an end remote from said valve opening, said control valve further including a tappet actuated by said electromagnet and engaging said remote end, and a spring for biasing said valve needle to an open position thereof, said electromagnet having an armature, said tappet having a rounded front end engaging said remote end of said valve needle.

2. A distribution fuel injection pump for delivering fuel to a plurality of injection nozzles of an internal combustion engine, said distribution fuel injection pump comprising an inlet communicating with a source of fuel;

an outlet for delivering fuel to the injection nozzles;

a pump working space communicating with said inlet and outlet;

at least one pump plunger defining at least partially said pump working space;

a rotatable distributor piston having a distributor bore communicating said pump working space with said outlet; and

a control valve for controlling fluid flow through said outlet, said distributor piston comprising a relief bore communicating with a relief space, said control valve comprising a valve opening located in said distributor piston and connecting said distribution and relief bores, a valve member located in said distributor piston for controlling fluid flow through said valve opening to thereby control the fluid flow between said distribution bore and said relief bore, and an electromagnet for controlling movement of said valve member;

said distributor piston comprising an axial guide bore, said valve member being formed as a valve needle displaceable in said axial guide bore and having an end remote from said valve opening, said control valve further including a tappet actuated by said electromagnet and engaging said remote end, and a spring for biasing said valve needle to an open position thereof.

3. A distribution fuel injection pump according to claim 2, wherein said distributor piston has a front end, said valve member has a stop surface projecting radially therefrom, said spring being supported against said front end of said distributor piston and said stop surface.

4. A distribution fuel injection pump according to claim 3, wherein said spring is a helical pressure spring.

5. A distribution fuel injection pump according to claim 3, wherein said spring is a plate spring.

6. A distribution fuel injection pump according to claim 2, wherein said relief bore is coaxial with said axial guide bore and has a bore diameter, said valve opening having a diameter which is less than the diameter of said relief bore.

7. A distribution fuel injection pump according to claim 6, wherein said distributor piston has a valve space communicating with said distribution bore and having opposite sides, said relief bore and said axial guide bore being located on said opposite sides of said valve space.

8. A distribution fuel injection pump according to claim 7, wherein said valve member has a portion located in said valve space, said portion having a shape such that a pressure prevailing in said valve space produces a force component acting on said valve member in an opening direction.

9. A distribution fuel injection pump according to claim 2, wherein said distributor piston has an axis, said pump working space being arranged at a right angle to said axis, said at least one pump plunger being formed as a radial piston, said fuel injection pump further comprising means for driving said radial piston, said driving means including a cam ring and a roller tappet engaging said radial piston and rolling on said cam ring, said cam ring being jointly rotatable with said distributor piston.