GB2287511A - Fuel-injection pumps for internal combustion engines - Google Patents
Fuel-injection pumps for internal combustion engines Download PDFInfo
- Publication number
- GB2287511A GB2287511A GB9503912A GB9503912A GB2287511A GB 2287511 A GB2287511 A GB 2287511A GB 9503912 A GB9503912 A GB 9503912A GB 9503912 A GB9503912 A GB 9503912A GB 2287511 A GB2287511 A GB 2287511A
- Authority
- GB
- United Kingdom
- Prior art keywords
- fuel
- front face
- closure part
- working chamber
- injection pump
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M51/00—Fuel-injection apparatus characterised by being operated electrically
- F02M51/02—Fuel-injection apparatus characterised by being operated electrically specially for low-pressure fuel-injection
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M41/00—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor
- F02M41/08—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined
- F02M41/10—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined pump pistons acting as the distributor
- F02M41/12—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined pump pistons acting as the distributor the pistons rotating to act as the distributor
- F02M41/123—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined pump pistons acting as the distributor the pistons rotating to act as the distributor characterised by means for varying fuel delivery or injection timing
- F02M41/128—Varying injection timing by angular adjustment of the face-cam or the rollers support
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Fuel-Injection Apparatus (AREA)
- High-Pressure Fuel Injection Pump Control (AREA)
Description
2287511
DESCRIPTION FUEL-INJECTION PUMPS FOR INTERNAL COMBUSTION ENGINES
The present invention relates to fuel-injection pumps for internal combustion engines.
A fuel-injection pump is known from the company publication of Robert Bosch GmbH "Distributor Injection Pump type VE, 1 987 722 014, KE/VDT-03. 8811 in which a sealing ring is used having a circular cross-section. Cavitation damage occurs in this case which is caused by the pressure variations, caused by changes in load, in the working chamber which is acted upon by the control pressure during operation of the fuel-injection pump.
In accordance with the present invention there is provided a fuelinjection pump for internal combustion engines, comprising a cam drive which in use operates at least one pump piston, and which can be adjusted in order to adjust the commencement of fuel injection by means of an adjusting piston which is displaceable in a cylinder, wherein a front face of the adjusting piston together with a closure part closing the cylinder delimits a working chamber in the cylinder, the working chamber being supplied in use with a hydraulic fluid, which is brought to a predetermined control pressure, and by means of which fluid the adjusting piston is adjustable against a return force, -2and wherein a sealing ring is mounted between the closure part and the adjoining front face of the cylinder wall an annular groove in the said front face, the annular groove being open towards the working chamber and the closure part, and wherein in the front face of the closure part facing the working -chamber there are disposed a plurality of radially inwardly directed recesses adjacent to the sealing ring.
This has the advantage that cavitation damage is avoided. By means of the recesses the implosion of gas bubbles which may occur in the control pressure fluid is displaced into the recesses and the sealing ring is thus protected from damage.
By way of example only specific embodiments of the present invention will now be described, with reference to the accompanying drawing.
The Figure shows a part of a distributor fuelinjection pump in crosssection. The distributor fuel-injection pumps has a pump piston which is driven by a cam disc to carry out a pumping movement and at the same time a rotating movement in which the pump piston serves as a distributor. The cam disc has an axially directed cam path. This cam path is held by resilient force on a roller ring 1 which is illustrated in a plan view in the cross-section d v 1 -3through the distributor fuel-injection pump shown in the Figure. This roller ring comprises an annular element 2 which is mounted in a pot- shaped recess in the pump housing 3 and has a circular outer contour. Rollers 6 mounted in an angular groove 4 and front face recesses 5 of the roller ring 1 serve to support the cam path of the cam disc, wherein this is rotationally driven by a drive shaft 7 penetrating the middle of the roller ring 1. The cam path running on the rollers produces the reciprocating pumping movements of the pump piston which is coupled to the cam disc.
With the aid of the said roller ring the moment of fuel injection or the commencement of the stroke of the pump piston with respect to the rotational position of the drive shaft can be changed. To this end and adjusting pin 9 is provided on the roller ring 1 and stands out radially from the roller ring. The adjusting pin is coupled to an adjusting piston 10 of the fuel-injection timing device 11 to adjust the commencement of fuel injection in the fuel-injection pump. The adjusting piston 10 is displaceably disposed in a cylinder 12 and with one of its front faces 14 delimits a working chamber 15, while its other front face 16 is acted upon by a return spring 18 which is supported on the other side at a cover 19 -4which shuts.off the cylinder on one side. The chamber thus enclosed between the adjusting piston 10 and the cover 19, forms a spring chamber which is relieved of pressure. The working chamber 15 is likewise closed by a cover 21 on the other side. Fuel under a predetermined control pressure is supplied to the working chamber by means of a bore 22 in the adjusting piston 10, which is provided with an uncoupling throttle, which control pressure is increased in the usual manner with increasing rotational speed and therefore displaces the adjusting piston 10 with increasing rotational speed against the force of the spring 18. The commencement of fuel injection is therefore advanced with increasing rotational speed.
In order to close the working chamber 15 in a sealed manner, a seal 25 is inserted between the cover 21 and the adjoining front face 23 of the wall surrounding the cylinder 12. This seal is produced in the form of a socalled O-ring, i.e. a ring with a circular cross-section made of elastic material, and is inserted into a groove 26 in the front face 23. This groove is open towards the cover 21 and radially inwards to the working chamber.
Axially directed blind bores 27 are provided in the cover and issue from the inner front face 28 of the cover parallel to the axis of the cylinder. These il -5bores are disposed in numerous embodiments in a regularly distributed manner radially inwards adjacent to the inner surface of the sealing ring. In a preferred embodiment four such blind bores are provided. These correspond to each other in diameter and depth in such a way that the gas bubbles occurring in the pressure fluid in the working chamber implode inside these blind bores when the load changes, so that there is no cavitation damage on the sealing ring. Such implosions regularly occur in the proximity of the wall and in the region of calm flow. Such places are provided with the above-described bores.
The invention was described with the aid of a fuel-injection commencement timing device in a distributor fuel-injection pump with stroke pistons. These types of adjustment of the commencements of fuel-injection with the aid of an adjusting piston are, however, also possible in the case of other embodiments of distributor pumps, for example radial piston pumps. The present invention can also be used in such pumps.
Claims (5)
1. A fuel-injection pump for internal combustion engines, comprising a cam drive which in use operates at least one pump piston, and which can be adjusted in order to adjust the commencement of fuel injection by means of an adjusting piston which is displaceable in a cylinder, wherein a front face of the adjusting piston together with a closure part closing the cylinder delimits a working chamber in the cylinder, the working chamber being supplied in use with a hydraulic fluid, which is brought to a predetermined control pressure, and by means of which fluid the adjusting piston is adjustable against a return force. and wherein a sealing ring is mounted between the closure part and the adjoining front face of the cylinder wall an annular groove in the said front face, the annular groove being open towards the working chamber and the closure part, and wherein in the front face of the closure part facing the working chamber there are disposed a plurality of radially inwardly directed recesses adjacent to the sealing ring.
2. A fuel-injection pump according to claim 1, wherein the recesses are regularly distributed about the front face of the closure part adjacent the inner periphery of the sealing ring.
3. A fuel-injection pump according to claim 2. wherein the recesses are blind bores which extend perpendicular to the front face of the closure part.
4. A fuel-injection pump according to any of the preceding claims, wherein there are four recesses.
5. A fuel-injection pump constructed and adapted to operate substantially as described herein with reference to, and as illustrated in, the drawing.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE4407617A DE4407617B4 (en) | 1994-03-08 | 1994-03-08 | Fuel injection pump for internal combustion engines |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9503912D0 GB9503912D0 (en) | 1995-04-19 |
| GB2287511A true GB2287511A (en) | 1995-09-20 |
| GB2287511B GB2287511B (en) | 1997-12-24 |
Family
ID=6512116
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9503912A Expired - Lifetime GB2287511B (en) | 1994-03-08 | 1995-02-27 | Fuel injection pumps for internal combustion engines |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPH07259583A (en) |
| KR (1) | KR100365631B1 (en) |
| CN (1) | CN1068654C (en) |
| DE (1) | DE4407617B4 (en) |
| FR (1) | FR2717226B1 (en) |
| GB (1) | GB2287511B (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2046351A (en) * | 1979-03-10 | 1980-11-12 | Bosch Gmbh Robert | A fuel injection pump for an internal combustion engine |
| WO1986005843A1 (en) * | 1985-04-02 | 1986-10-09 | Robert Bosch Gmbh | Fuel injection pump |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3861833A (en) * | 1973-02-28 | 1975-01-21 | Stanadyne Inc | Fuel injection pump |
| DE2930499A1 (en) * | 1979-07-27 | 1981-02-12 | Bosch Gmbh Robert | Fuel injection pump for diesel engine - has annular groove round discharge valve seat to reduce cavitation in fuel |
| JPS5786533A (en) * | 1980-11-15 | 1982-05-29 | Diesel Kiki Co Ltd | Regulating device of injection timing in distributor type fuel injection pump |
| DE3900345A1 (en) * | 1989-01-07 | 1990-07-12 | Bosch Gmbh Robert | DISTRIBUTION FUEL INJECTION PUMP FOR INTERNAL COMBUSTION ENGINES |
-
1994
- 1994-03-08 DE DE4407617A patent/DE4407617B4/en not_active Expired - Lifetime
-
1995
- 1995-02-08 FR FR9501446A patent/FR2717226B1/en not_active Expired - Lifetime
- 1995-02-27 GB GB9503912A patent/GB2287511B/en not_active Expired - Lifetime
- 1995-03-06 JP JP7045872A patent/JPH07259583A/en active Pending
- 1995-03-07 KR KR1019950004567A patent/KR100365631B1/en not_active IP Right Cessation
- 1995-03-08 CN CN95104048A patent/CN1068654C/en not_active Expired - Lifetime
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2046351A (en) * | 1979-03-10 | 1980-11-12 | Bosch Gmbh Robert | A fuel injection pump for an internal combustion engine |
| WO1986005843A1 (en) * | 1985-04-02 | 1986-10-09 | Robert Bosch Gmbh | Fuel injection pump |
| US4778358A (en) * | 1985-04-02 | 1988-10-18 | Robert Bosch Gmbh | Fuel injection pump |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2717226B1 (en) | 1997-01-10 |
| DE4407617B4 (en) | 2010-08-12 |
| CN1068654C (en) | 2001-07-18 |
| KR950033063A (en) | 1995-12-22 |
| CN1120630A (en) | 1996-04-17 |
| DE4407617A1 (en) | 1995-09-14 |
| GB2287511B (en) | 1997-12-24 |
| JPH07259583A (en) | 1995-10-09 |
| FR2717226A1 (en) | 1995-09-15 |
| KR100365631B1 (en) | 2003-02-25 |
| GB9503912D0 (en) | 1995-04-19 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PE20 | Patent expired after termination of 20 years |
Expiry date: 20150226 |