US4172699A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Chamber-controlled fuel injection pump for internal combustion engines
Assignee: Robert Bosch GmbH
•
Filing: 1978-05-15
•
Granted: 1979-10-30
•
Expires: 1998-05-15
Abstract
Abstract A fuel injection pump for internal combustion engines, which has improved and simplified means for a throttled preliminary shut-off to prevent cavitation in the injection system and late injections by the fuel injection valves. The pump piston is provided with two recesses that terminate in chamfered control edges and control the end of the delivery cycle and also contains a throttle bore, which has a cross bore, and connects the first recess, which is opened shortly before the other recess, with the pump operating chamber by means of a longitudinal bore in the pump piston. The second recess has an unthrottled connection to the pump operating chamber.
Inventors
- 👤 Walter Hafele
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 18:44
CPC Classifications
F; F02; F02M; F02M59/00; F02M59/20; F02M59/24; F02M59/26; F02M59/265
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
195 words
An oblique-edge-controlled fuel injection pump for internal combustion engines having an axially and rotationally movable pump piston guided in a pump cylinder, which pump piston includes two diametrically opposite recesses, delimited by oblique control edges, in its outer surface, which recesses are in continual communication with the pump operating chamber and can be connected with a low pressure chamber through two control bores lying opposite each other in the wall of the pump cylinder to terminate the effective fuel delivery stroke, and of which the first recess can be opened shortly before the second by its associated control bore and serves as an element of a connecting line from the pump operating chamber to the low pressure chamber which is provided with a throttle point, the improvement wherein said first recess is connected exclusively with a blind-bore type longitudinal bore through a cross bore, said longitudinal bore being arranged to extend from the pump operating chamber into said pump piston and that said cross bore is formed to provide a throttle bore whose diameter (D 1 ) is not more than one fourth of the diameter (D 2 ) of one of said control bores.
Claim 2
Dependent Claim
195 words
An oblique-edge-controlled fuel injection pump for internal combustion engines having an axially and rotationally movable pump piston guided in a pump cylinder, which pump piston includes two diametrically opposite recesses, delimited by oblique control edges, in its outer surface, which recesses are in continual communication with the pump operating chamber and can be connected with a low pressure chamber through two control bores lying opposite each other in the wall of the pump cylinder to terminate the effective fuel delivery stroke, and of which the first recess can be opened shortly before the second by its associated control bore and serves as an element of a connecting line from the pump operating chamber to the low pressure chamber which is provided with a throttle point, the improvement wherein said first recess is connected exclusively with a blind-bore type longitudinal bore through a cross bore, said longitudinal bore being arranged to extend from the pump operating chamber into said pump piston and that said cross bore is formed to provide a throttle bore whose diameter (D 1 ) is not more than one fourth of the diameter (D 2 ) of one of said control bores.
Claim 3
Dependent Claim
29 words
A fuel injection pump as claimed in claim 1, wherein said oblique control edges (α 1 , α 2 ) are arranged at varying degrees of angulation (FIG. 5).
Claim 4
Dependent Claim
47 words
A fuel injection pump as claimed in claim 1, wherein at least one of said recesses is connected with said longitudinal bore through a second cross bore which is arranged in an extension of the throttle bore and produces an unthrottled connection to said pump operating chamber.
Claim 5
Dependent Claim
29 words
A fuel injection pump as claimed in claim 3, wherein said oblique control edges (α 1 , α 2 ) are arranged at varying degrees of angulation (FIG. 5).
Claim 6
Dependent Claim
23 words
A fuel injection pump as claimed in claim 1, wherein said pump operating chamber is arranged to be closed by a pressure valve.
Claim 7
Dependent Claim
25 words
A fuel injection pump as claimed in claim 5, wherein said pressure valve is spring loaded and arranged to function as a return flow valve.
Claim 8
Dependent Claim
58 words
A fuel injection pump as claimed in claim 1, wherein said pump cylinder has a terminal end portion and further wherein the one of said control bores which cooperates with the first recess to control the end of fuel delivery is arranged farther away from said terminal end portion of said pump cylinder than said other control bore.
Claim 9
Dependent Claim
29 words
A fuel injection pump as claimed in claim 7, wherein said oblique control edges (α 1 , α 2 ) are arranged at varying degrees of angulation (FIG. 5).
Claim 10
Dependent Claim
27 words
A fuel injection pump as claimed in claim 7, wherein said bores are spaced apart by a distance a to effect throttled preliminary shut-off of fuel flow.
Claim 11
Dependent Claim
23 words
A fuel injection pump as claimed in claim 9, wherein said pump operating chamber is arranged to be closed by a pressure valve.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-10-29 | 1983-04-30 | 1983-10-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-10-29 | 1987-04-30 | 1987-10-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-10-29 | 1991-04-30 | 1991-10-30 | $7700.00 | Window Closed / Lapsed |