Internal-combustion engines – Charge forming device – With fuel pump
Patent
1997-05-12
1998-06-23
Miller, Carl S.
Internal-combustion engines
Charge forming device
With fuel pump
123450, F02M 3704
Patent
active
057690561
DESCRIPTION:
BRIEF SUMMARY
PRIOR ART
The invention is based on a fuel injection pump for a vehicle. DE 35 32 719 discloses a fuel injection pump of this kind in which the pressure fluid supply to the cylinder bore takes place via a check valve, while the pressure fluid discharge proceeds via the chamber that contains the restoring spring. The control slide valve end face which is subjected to the control pressure defines the control chamber in the cylinder bore over the entire diameter of the cylinder bore, which chamber, on the other end, communicates with a control pressure inlet via a throttle. Injection timing mechanisms of this kind are very sensitive to control pressure fluctuations and have a tendency for the control slide valve to execute oscillating movements relative to the injection timing mechanism, which leads to an unstable work behavior of the injection timing mechanism. In fact, the throttle bore has the effect that kicks back on the control pressure supply end, which are produced by the operation of the fuel injection pump, should have as little effect as possible on the control slide valve, but a balanced, average working pressure, which is effective in the control chamber, is only incompletely achieved.
ADVANTAGES OF THE INVENTION
The fuel injection pump according to the invention, has the advantage over the prior art that the control slide valve is additionally damped in its movements so that nevertheless, pressure fluctuations occurring in the control chamber do not reach through and indirectly excite the control slide valve. If the control piston is excited to oscillate by pressure surges, the fluid enclosed in the blind bore by the pin is first displaced by means of the throttle gap. The throttle action, which is produced as a result, effectively suppresses the tendency of the control piston to oscillate.
BRIEF DESCRIPTION OF THE DRAWING
An exemplary embodiment of the invention is shown in cross section in the drawing and explained in detail in the ensuing description.
DESCRIPTION OF THE EXEMPLARY EMBODIMENT
Fuel injection pumps of the distributor type can be provided either as pumps with an axially driven pump piston that is used as both a distributor and a pump piston, or radial pistons can be provided, which feed radially into a supply conduit disposed in a distributor. FIG. 1 shows a section through a so-called radial piston pump of this kind, which is of the known type. Four pump pistons 1 are provided, which are supported so they can sealingly slide in radial bores 3 of the distributor 2, at the same angular spacing in a common plane radial to the axis of the distributor 2. On their one end face, they enclose a common pump work chamber 4, which is filled with fuel via a metering device in a known manner not shown in detail here during the radial outward stroke of the pump piston 1, and during the radial inward stroke of the pump piston, communicates via a pressure line, likewise not visible here, with a distributor opening on the jacket face of the distributor 2, wherein the distributor opening controls injection lines that lead from the circumference of the distributor, one of the lines is respectively supplied with fuel that has been brought to injection pressure when the pump piston is moved inward. Through means not shown in detail, a drive shaft drives the distributor to rotate in such a way that on the one hand, the distributor opening can carry out its control function and on the other hand, the pump piston is moved in the circumference direction. Roller tappets 6 rest against the end disposed opposite the pump work chamber 4 and follow a cam track 7 which is disposed on a cam ring 8, on its annular face that points inward toward the distributor. The cam ring 8 represents essentially the stationary part of the cam drive of the pump piston. While the device that moves the pump pistons, which for example can be the ring 9 that guides the roller tappets 6, which ring is coupled to the drive shaft, represents the moving part of the cam drive. The adjustment of the cam ring, which is guided w
REFERENCES:
patent: 4476837 (1984-10-01), Salzgeber
patent: 4798189 (1989-01-01), Thornwaite
patent: 4920940 (1990-05-01), Harris
patent: 5123393 (1992-06-01), Djordjevic
patent: 5125802 (1992-06-01), Nakamura
patent: 5263457 (1993-11-01), Konrath
patent: 5647327 (1997-07-01), Enomoto
Geiger Wolfgang
Kulder Thomas
Greigg Edwin E.
Greigg Ronald E.
Miller Carl S.
Robert & Bosch GmbH
LandOfFree
Fuel injection pump does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Fuel injection pump, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fuel injection pump will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1385529