Pumps – Expansible chamber type – Pumping member position controlled port
Patent
1998-12-04
2000-11-28
Freay, Charles G.
Pumps
Expansible chamber type
Pumping member position controlled port
123506, F04B 704
Patent
active
061527084
DESCRIPTION:
BRIEF SUMMARY
PRIOR ART
The invention relates to a fuel injection pump for internal combustion engines. A fuel injection pump of this kind has been disclosed by DE-C-24 49 332, which has a pump piston that is driven to both reciprocate and also rotate in a housing bore. The outlet opening on the pump piston is used as a distributor opening, by way of which different pressure lines in succession can be supplied with high-pressure fuel. In this known fuel injection pump, approximately opposite from the distributor opening, a longitudinal groove is disposed in the jacket face of the pump piston, and this groove continuously communicates with the high-pressure fuel supplied to the distributor opening. With an embodiment of this kind, an application of pressure is produced between the pump piston and the housing bore, approximately diametrically opposite from the distributor opening, in such a way that the pump piston is uniformly loaded by compressive forces and the tendency of the piston to seize inside the housing bore is reduced. The additional groove regularly comes into communication with injection lines or with pressure lines not involved in the injection and in an intake phase of the pump piston, carries out a pressure compensation between these lines with an injection line that is simultaneously opened by the distributor opening.
This embodiment has the disadvantage that despite a force compensation that is achieved in the pump piston, an interruption of a lubricating oil film occurs due to the wide grooves in the jacket face of the moving part, which lubricating oil film is intended to carry the moving part, which is both the pump piston and the distributor, when it rotates in the housing bore.
ADVANTAGES OF THE INVENTION
The fuel injection pump according to the invention, has the advantage over the prior art that the pressure compensation surface according to the invention produces a compensation force that is independent of the rotational position of the moving part since the pressure compensation surface always remains intrinsically closed. The pressure that prevails in the region of the pressure compensation surface and is diverted by the output pressure of the high-pressure source to the adjoining outlet opening can be adjusted by dimensioning the first and second leakage routes in the desired fashion. This embodiment also has the advantage that with the high pressure that occurs in the region of the outlet opening as a result of the intermittently occurring high-pressure fuel injection, due to the deformation of the moving part on the one hand and of the housing bore on the other hand, the magnitude of the leakage routes, in particular their effective through flow cross section, is influenced so that an outflow cross section by way of the second leakage route is reduced and an inflow cross section by way of the first leakage route is increased. As a result, in the region of the pressure compensation surface, the pressure increases superproportionally with increasing high pressure. This pressure, which tends to increase more rapidly, produces a correspondingly higher compensation force counter to the force that is produced in the region of the outlet opening with the high-pressure increase. The lateral force resulting from the sum of the forces therefore only increases slowly as the pressure level of the high-pressure source rises. On the other hand, the compensation force decreases the deformation on the moving part and the housing bore containing it. In the moving part, these deformations are flattenings of the circular cross section in the direction of an elliptical cross section and in the housing bore, they are bore widenings, likewise with an elliptical cross section, wherein the main axes of the respective cross sections are disposed perpendicular to each other. With a reduction of this deformation, lesser lateral contractions or lateral widenings also occur lateral to the deformations being produced so that a smaller play between the moving part and the housing bore can be achieved in the fundament
REFERENCES:
patent: 3942914 (1976-03-01), Hofer et al.
patent: 4537170 (1985-08-01), Yamada et al.
patent: 4635605 (1987-01-01), Faupel et al.
patent: 4718385 (1988-01-01), Konrath
patent: 4741314 (1988-05-01), Hofer
patent: 4788959 (1988-12-01), Iiyama et al.
patent: 4831986 (1989-05-01), Linder et al.
patent: 4924833 (1990-05-01), Hofer et al.
patent: 5007400 (1991-04-01), Babitzka
patent: 5161509 (1992-11-01), Krieger et al.
Bonse Berhard
Braun Wolfgang
Greif Hubert
Gronenberg Roland
Junger Dieter
Evora Robert Z.
Freay Charles G.
Greigg Edwin E.
Greigg Ronald E.
Robert & Bosch GmbH
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