GB2112082A - Fuel injection pump - Google Patents
Fuel injection pump Download PDFInfo
- Publication number
- GB2112082A GB2112082A GB08232789A GB8232789A GB2112082A GB 2112082 A GB2112082 A GB 2112082A GB 08232789 A GB08232789 A GB 08232789A GB 8232789 A GB8232789 A GB 8232789A GB 2112082 A GB2112082 A GB 2112082A
- Authority
- GB
- United Kingdom
- Prior art keywords
- fuel
- body portion
- bore
- plunger
- nozzle
- 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
- 239000000446 fuel Substances 0.000 title claims abstract description 37
- 238000002347 injection Methods 0.000 title claims abstract description 13
- 239000007924 injection Substances 0.000 title claims abstract description 13
- 239000000463 material Substances 0.000 claims abstract description 7
- 230000006835 compression Effects 0.000 description 3
- 238000007906 compression Methods 0.000 description 3
- 230000003628 erosive effect Effects 0.000 description 3
- 238000002485 combustion reaction Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
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
- F02M57/00—Fuel-injectors combined or associated with other devices
- F02M57/02—Injectors structurally combined with fuel-injection pumps
-
- 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
- F02M55/00—Fuel-injection apparatus characterised by their fuel conduits or their venting means; Arrangements of conduits between fuel tank and pump F02M37/00
- F02M55/001—Pumps with means for preventing erosion on fuel discharge
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Fuel-Injection Apparatus (AREA)
Abstract
A fuel injection pump of the kind including a body portion 10 in which is formed a bore 11 having a reciprocable plunger located therein. A spill port 26 extends to the exterior of the body portion from the bore and is uncovered by the plunger to terminate fuel flow to an injection nozzle 16. The nozzle is secured to the body portion 10 by a cap nut 31 and the cap nut has an extended skirt portion 33 which overlaps the spill port 26 in spaced relationship with the body portion. The skirt portion may be of hardened material or softer material which mounts an insert 34 formed from hardened material. The jet of fuel leaving the spill port impinges on the hardened skirt portion or insert. <IMAGE>
Description
SPECIFICATION
Fuel injection pump
This invention relates to a fuel injection pump of the kind comprising an elongated body portion, a pump plunger slidable within a bore formed in the body portion, said plunger projecting from one end of said bore, a fuel injection nozzle through which fuel displaced by the pump plunger can flow, a cap nut for retaining the nozzle in assembled relationship with the body portion and a spill port formed in the body portion through which fuel can escape from said bore when the plunger has been moved a predetermined distance towards the other end of said bore, thereby to terminate flow of fuel through said nozzle.
An example of the pump of the aforesaid kind is disclosed in British Published Publication 2062093A. Such a pump is intended to be mounted within the recess formed in the cylinder head of an engine, the recess being shaped to define a fuel supply gallery about the body portion of the pump, the aforesaid spill port discharging fuel into said gallery. It is known that the velocity of the fuel leaving said spill port may be such as to cause erosion of the wall of the gallery and the object of the present invention is to provide a pump of the aforesaid kind in which the risk of damage to the wall of the gallery is minimised.
According to the invention in a pump of the kind specified said cap nut is provided with an extended skirt portion which extends over said spill port in spaced relationship with the body portion, said skirt portion being formed from hardened material or mounting an insert of hardened material upon which the fuel leaving said spill port impinges in use.
An example of a fuel injection pump in accordance with the invention will now be described with reference to the accompanying drawing which is a part sectional side elevation of the pump shown mounted within a bore in the cylinder head of an engine.
Referring to the drawing the injection pump comprises an elongated body portion 10 in which is defined a blind bore 11 in which is mounted a reciprocable plunger 1 2. The plunger extends from the open end of the bore and carries a spring abutment 13 against which is located one end of a coiled compression spring 14. The other end of the compression spring bears against the body portion so that the spring biases the plunger in an outwards direction. Moreover, a lever 1 5 is provided which is coupled to the plunger so that the angular setting of the plunger within the bore can be adjusted for the purpose of determining the amount of fuel which is supplied by the pump. The plunger is arranged to be moved inwardly against the action of the spring 14 by means of a cam not shown which is driven by an engine cam shaft.
At the opposite end of the body portion to the spring abutment there is located a fuel injection nozzle generally indicated at 1 6. The nozzle is of the so-called inwardly opening type and has outlet orifices 1 7 through which fuel flows to a combustion space of the engine. The nozzle includes a valve member having a stem 18 which projects from the nozzle and which mounts a spring abutment 1 9 located within a chamber 20 which aiso accommodates a coiled compression spring 21 one end of which engages the abutment 1 9 and the other end of which engages a shim 22 disposed against the end wall of the chamber. The spring biases the valve member of the nozzle to the closed position.Interposed between the body of the nozzle and the body portion 10 is a spacing plate 23 having an aperture through which the stem 1 8 extends and the plate is also provided with a connecting passage 24 which is aligned with a fuel delivery passage 25 formed in the body portion and with a fuel inlet passage forming part of the nozzle. The passage 25 communicates with the blind end of the bore 11.
Formed in the wall of the bore 11 is a spill port 26 which communicates with a fuel supply gallery 27 defined in the wall of the bore in the cylinder head of the engine. The gallery 27 communicates with a source 28 of fuel under pressure.
Formed on the peripheral surface of the plunger is an inclined groove 29 which communicates with the blind end of the bore by way of an axial groove 30. In known manner, the groove 29 cooperates with the spill port 26 to terminate flow of fuel through the passage 25 to the injection nozzle. As previously stated the angular position of the plunger 12 is adjustable and therefore the angular setting determines the amount of fuel which is supplied through the nozzle to the associated engine. When the groove 29 communicates with the port 26 fuel at high pressure flows from the pumping chamber defined by the blind end of the bore, through the port 26 and it is well known that the fuel can cause erosion of any metallic wall against which this jet of fuel impinges.
The nozzle 1 6 and the body portion 10 together with the plate 23 are held in assembled relationship by means of a cap nut 31. The nut engages a shoulder on the nozzle and is in screw thread engagement with the body portion in a region generally indicated at 32. The skirt portion of the cap nut is however extended as shown at 33 to overlap the port 26. The extended portion is however disposed in spaced relationship to the body portion of the pump.
The extended portion 33 of the skirt can be hardened so as to present a hardened surface to the fuel escaping through the port 26. On the other hand and as shown, the extended portion of the skirt can be provided with a hardened insert 34 which faces the port 26. Preferably the insert is of annular form so that alignment problems are not encountered when the cap nut is tightened.
The jet of fuel issuing through the port 26 strikes the hardened surface presented by the insert or the skirt portion of the cap nut and its energy is dissipated prior to the fuel flowing into the gallery. In this way erosion of the wall of the gallery is avoided. It will be appreciated that the port 26 will also serve as a filling port during outward movement of the plunger under the action of the spring 14.
Claims (2)
1. A fuel injection pump comprising an elongated body portion, a pump plunger slidable within a bore formed in the body portion, said plunger projecting from one end of said bore, a fuel injection nozzle through which fuel displaced by the pump plunger can flow, a cap nut for retaining the nozzle in assembled relationship with the body portion and a spill port formed in the body portion through which fuel can escape from said bore when the plunger has been moved in a predetermined distance towards the other end of said bore, thereby to terminate flow of fuel through said nozzle, an extended skirt portion on said cap nut, said skirt portion extending over said spill port in spaced relationship with the body portion, said skirt portion being formed from hardened material or mounting an insert of hardened material upon which the fuel leaving the spill port impinges in use.
2. A fuel injection pump comprising the combination and arrangement of parts substantially as hereinbefore described with reference to the accompanying drawing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08232789A GB2112082B (en) | 1981-12-18 | 1982-11-17 | Fuel injection pump |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8138317 | 1981-12-18 | ||
| GB08232789A GB2112082B (en) | 1981-12-18 | 1982-11-17 | Fuel injection pump |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2112082A true GB2112082A (en) | 1983-07-13 |
| GB2112082B GB2112082B (en) | 1984-12-19 |
Family
ID=26281580
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08232789A Expired GB2112082B (en) | 1981-12-18 | 1982-11-17 | Fuel injection pump |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2112082B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2561716A1 (en) * | 1984-03-23 | 1985-09-27 | Lucas Ind Plc | FUEL INJECTOR |
| AT389920B (en) * | 1984-07-30 | 1990-02-26 | Voest Alpine Automotive | FUEL INJECTION PUMP FOR INTERNAL COMBUSTION ENGINES |
-
1982
- 1982-11-17 GB GB08232789A patent/GB2112082B/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2561716A1 (en) * | 1984-03-23 | 1985-09-27 | Lucas Ind Plc | FUEL INJECTOR |
| AT389920B (en) * | 1984-07-30 | 1990-02-26 | Voest Alpine Automotive | FUEL INJECTION PUMP FOR INTERNAL COMBUSTION ENGINES |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2112082B (en) | 1984-12-19 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |