GB2056123A - Injection-timing regulator for a fuel injection pump - Google Patents
Injection-timing regulator for a fuel injection pump Download PDFInfo
- Publication number
- GB2056123A GB2056123A GB8024590A GB8024590A GB2056123A GB 2056123 A GB2056123 A GB 2056123A GB 8024590 A GB8024590 A GB 8024590A GB 8024590 A GB8024590 A GB 8024590A GB 2056123 A GB2056123 A GB 2056123A
- Authority
- GB
- United Kingdom
- Prior art keywords
- bore
- injection
- valve
- suction chamber
- timing
- 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 36
- 238000002347 injection Methods 0.000 title claims abstract description 34
- 239000007924 injection Substances 0.000 title claims abstract description 34
- 230000008859 change Effects 0.000 abstract description 2
- 230000001419 dependent effect Effects 0.000 abstract description 2
- 238000002485 combustion reaction Methods 0.000 description 4
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 3
- 239000002828 fuel tank Substances 0.000 description 3
- 230000001105 regulatory effect Effects 0.000 description 3
- 230000001133 acceleration Effects 0.000 description 2
- 230000009471 action Effects 0.000 description 2
- 239000000428 dust Substances 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 230000001771 impaired effect Effects 0.000 description 2
- 230000007246 mechanism Effects 0.000 description 2
- 241000287828 Gallus gallus Species 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 239000000498 cooling water Substances 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000006735 deficit Effects 0.000 description 1
- 230000000994 depressogenic effect Effects 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000000779 smoke Substances 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D1/00—Controlling fuel-injection pumps, e.g. of high pressure injection type
- F02D1/16—Adjustment of injection timing
- F02D1/18—Adjustment of injection timing with non-mechanical means for transmitting control impulse; with amplification of control impulse
- F02D1/183—Adjustment of injection timing with non-mechanical means for transmitting control impulse; with amplification of control impulse hydraulic
-
- 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
-
- 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
- F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
- F02M59/44—Details, components parts, or accessories not provided for in, or of interest apart from, the apparatus of groups F02M59/02 - F02M59/42; Pumps having transducers, e.g. to measure displacement of pump rack or piston
- F02M59/46—Valves
- F02M59/466—Electrically operated valves, e.g. using electromagnetic or piezoelectric operating means
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Fuel-Injection Apparatus (AREA)
- High-Pressure Fuel Injection Pump Control (AREA)
Abstract
An injection-timing regulator in fuel injection pump has a timing piston subjected to the fuel pressure in the pump suction chamber 5, which pressure is controlled in dependence upon engine speed. An optimum instant of injection is obtained by further controlling the fuel pressure in the chamber 5 in dependence upon operating conditions of the engine by means of a solenoid adjustable relief valve 28. At low load, the speed- dependent pressure in the suction chamber 5 is relieved via a first bore 44 and via a second bore 47. At high load, the coil 33 is energised to change over the valve member 35 and so close the second bore 47 and increase the resistance to the relief fuel flow. This increases the pressure in the suction chamber 5 and so advances the instant of onset of injection. There is a continuous fuel flow through a bore 52 in the closure member 35 to an annular groove 51 and this wipes the bore 36 of the valve housing 30 clean. <IMAGE>
Description
SPECIFICATION
Injection-timing regulator for a fuel injection pump
The invention relates to injection timing regulators for fuel injection pumps for internal combustion engines.
Since it is known that the instant at which fuel is injected in a diesel engine has to be advanced as the engine speed increases, a known injectiontiming regulator for fuel injection pumps incorporates a timing piston which is subjected to the suction pressure in the injection pump housing, and the displacement of this piston is transmitted to an injection-timing control element.
Fuel is fed to the injection pump housing by means of a fuel feed pump which is driven synchronously by the internal combustion engine, the pressure of the fuel being adjusted by means of a pressure-control valve in dependence upon engine speed.
However, with control of this kind, it is impossible to control the instant of injection in dependence upon ioad. If the instant of injection is correctly set for operation at full load, the instant of injection during part load is too advanced, this being associated with the generation of smoke or impaired efficiency of the engine. Conversely, if the instant of injection is adapted to part load operation, the instant of injection is retarded relative to the optimum adjustment during full load, thus resulting in a reduction of power or impairment of the exhaust gases.
An injection-timing regulator, in accordance with the invention, for a fuel injection pump comprises an injection timing device which incorporates a timing piston subjected against the force of a spring to a pressure maintained in a suction chamber of a fuel injection pump in dependence upon engine speed, and a relief valve which leads from the suction chamber, the relief valve being a solenoid valve which is switchable in dependence upon at least one engine operating parameter and having a valve closure member in the form of a valve slide which is displaceable in a cylindrical valve housing bore open towards the suction chamber, which valve slide has a longitudinal bore permanently connected to the suction chamber and a reduced diameter portion which is located on the outer periphery and which forms between the valve slide and the cylindrical bore a space which on the one hand is permanently connected to the longitudinal bore by way of a radial bore and, on the other hand, is permanently connected to a first relief bore in the wall of the valve housing, and the longitudinal bore in the valve slide being connected to a second relief bore by way of an additional bore in the valve slide when the valve slide is in a first position.
This has the advantage that a change in the pressure in the injection pump housing is not only obtained with reference to the engine speed, but is also obtained with reference to the other operating factors of the internal combustion
engine, and thus the instant of injection can also
be timed in dependence upon, for example, the
load or upon acceleration or other factors of this
kind.
The invention is further described, by way of
example, with reference to the drawings, in which Fig. 1 is a longitudinal section through one
embodiment of a distributor-type fuel injection
pump equipped with an injection-timing regulator
in accordance with the invention,
Fig. 2 is a section through the embodiment of
Fig. 1, taken on the line Il-Il, and
Fig. 3 is a section, drawn to a larger scale, through an important part of the embodiment of
Fig. 1.
In the distributor-type fuel injection pump illustrated in Figures 1 and 2, fuel located in a fuel tank 1 is delivered into a suction chamber 5 of an
injection pump housing 4 by a fuel feed pump 3 driven by a drive shaft 2 of the engine. A pressurecontrol valve 8 controlled by a spring 7 is provided in a by-pass line 6 which interconnects the suction side and the delivery side of the fuel feed pump 3, and, as a result of the equilibrium between the compressive stress of the above-mentioned spring 7 and the feed pressure of the feed pump 3, the fuel pressure in the suction chamber 5 is made correspondingly dependent upon engine speed by varying the outflow cross-section.
A piston 10 simultaneously serving as a pump piston and as a distributor is disposed in a cylinder 9 incorporated in the pump housing 4. A cam plate 11 rigidly secured to the end of the piston
10, and the above-mentioned drive shaft 2, are non-relatively rotatably interconnected by means of a drive disc (not shown). A can face having a number of lobes corresponding to the number of engine cylinders is formed on the abovementioned cam plate 11 which, by means of a piston spring (not illustrated), is held on, and pressed against, rollers of a roller holder 12 which is adjustable by a timing piston which will be further described below.
Thus, whilst the piston 10 is performing a rotary movement for distributing fuel during rotation of the drive shaft 2, the piston 1 0 performs, under the action of the cam face of the cam plate 11 and the broilers 13, a reciprocating movement for drawing in the fuel and delivering it under pressure.When the piston 10 is performing its suction stroke, the fuel delivered into the suction chamber 5 is drawn into the pump working chamber 1 6 by way of a suction line 14 and a suction groove 15, and, when the piston 10 moves into its pressure delivery stroke, the fuel in the pump working chamber 16 is pressurised and is then delivered into the pressure delivery line 1 8 through a distributor groove 1 5 and is delivered under pressure into the injection nozzles (not illustrated) provided in the individual cylinders of the internal combustion engine by way of a respective non-return valve 1 9. A number of the above-mentioned pressure delivery lines 1 8 corresponding to the number of cylinders is uniformly distributed around the periphery of the piston in the same plane.When the pressure delivery lines 18 come into register with the distributor groove 17 during the rotary movement and reciprocating movement of the piston 10, they feed fuel to the individual cylinders in a predetermined sequence.
A control sleeve 20, adapted to that portion of the piston 10 which extends into the suction chamber 5, closes and, during the reciprocating movement of the piston 10, opens an outlet port of a spill passage 21, which extends through the piston 10 and leads from the pump working chamber. The fuel which is located in the piston chamber 16, and which is delivered by the piston 10, flows into the suction chamber 5 from the instant at which the outlet port is opened by the control sleeve 20, so that the injection operation is terminated. The position of the control sleeve 20 is regulated by a governor mechanism 22 and thus controls the quantity of fuel injected.
The above-mentioned roller holder 12 is disposed so as to be rotatable concentrically of the piston 10, and the end of a lever 23, which is connected to the said holder 12, is brought into engagement with the timing piston 24.
An actuating chamber 26 (Fig. 2) is formed at one end face of the timing piston 24 and is connected to the suction chamber 5 by way of a bore 25. Referring to Figure 2, the timing piston 24 is displaced from left to right such that the pressure in the said actuating chamber 26, and the load effected by the compressive stress of the spring 27 acting upon the opposite end, are maintained in equilibrium. The lever 23 is correspondingly displaced, and thus the position of the roller holder 12 in the direction of rotation is determined. When the pressure in the suction chamber 5 rises as the engine speed increases, the pressure in the actuating chamber 26 also rises.Consequently, the timing piston 24 is displaced to the right as viewed in the drawing against the force of the spring 27, and the lever 23 angularly displaces the roller holder 12 in a direction opposite to the direction of rotation of the piston 1 0. For this reason, the piston 10 is moved into its pressure delivery stroke at a predetermined earlier instant of time, so that the angle of the instant of injection is advanced. When the pressure in the suction chamber 5 has dropped, that is to say, when the engine speed has been reduced, the timing piston 24 is displaced to the left as viewed in the drawing, and the angle by which the instant of injection is advanced is reduced.
A relief valve 28 for surplus fuel is provided in the pump housing 4 and is of the construction shown in Figure 3.
The front end 31 of the housing 30 of a solenoid valve is provided with a screw thread and is screwed into a screw-threaded bore 29 which leads from the outside and through the pump housing 4 into the suction chamber 5. The valve housing 30 incorporates an electromagnet having a coil 33 wound onto a fixed iron core 32 and a piston-like change-over valve closure member 35 which constitutes a movable iron core and which is located opposite the above-mentioned fixed iron core 32 with a spring 34 interposed therebetween. The change-over valve closure member 35 is fitted in a cylindrical bore 36 so as to be freely displaceable and its axial displaceability is limited at its end remote from the spring 34 by a screw-threaded bush 38 which is screwed into the bore 36 from the suction chamber.When the electromagnet is deenergized, the closure member 35 shown in Figure 3 is moved downwardly by the spring 34 until it abuts against, and is held on, the screw-threaded bush 38 and, when the coil receives current and is energized, the closure member 35 is moved upwardly against the force of the spring 34.
Coaxial through bores 40 and 42 are formed in the screw-threaded bush 38 and in the closure member 35 respectively, the through bore 40 in the screw-threaded bush 38 opening into the space between the screw-threaded bush, the closure member 35 and the bore 36 by way of a radial groove 43 formed in that end face of the closure member 35 of the change-over valve which is remote from the spring 34. The said space is connected to the exterior of the housing 30 by way of a first relief bore 44. The abovementioned through bore 42 is connected by way of radial bores 45 to an annular groove 46 formed in the outer circumferential surface of the changeover valve closure member 35.When the closure member 35 is in its bottom end position, communication is established by way of the annular groove 46 with a second relief bore 47 interconnecting the interior and the exterior of the housing 30, while the interior and the exterior of the housing 30 are interconnected exclusively by way of the above-mentioned first relief bore 44 when the closure member has moved upwardly.
Furthermore, that end of the change-over valve 35 which faces the stop incorporates a portion of small external diameter to form a space 51 between the said portion and the bore 36. A small radial bore 52 connects the through bore 42 to the space 51. Thus, overflowing fuel permanently flows between the closure member 35 and the bore 36, so that it is possible to prevent corrosion by dust or the like between the closure member 35 and the bore 36. The outer end of the abovementioned first relief bore 44 and the outer end of the above-mentioned second relief bore 47 open into a collector 48 to which is connected a conduit 49 which, as is shown in Figure 1, is connected to the fuel tank 1.
On the other hand, the above-mentioned coil 33 is connected by way of a connection terminal 50 to a control unit (not illustrated in the drawing) by which the flow of current through the coil is controlled in dependence upon signals which are related to the various operating data of the engine, such as load, temperature, acceleration and speed.
Thus, for example, the depressed position of an accelerator pedal (not illustrated in the drawing), the position of the above-mentioned control sleeve 20, or the position of a draw lever, or the like, of the governor mechanism 22, is sensed for the signals associated with the load. The signals associated with temperature, such as the temperature of the engine cooling water, the temperature of the fuel, the temperature of the intake air, or the temperature of the exhaust gases, are tapped and are fed into the control unit.
By way of example, the control unit is set during full load so as to feed current to the coil 33. The change-over valve 35 thereby moves upwardly during full load operation. The second relief bore 47 is closed, since the annular groove 46 and the second relief bore 47 are not in register with one another. Since, as a consequence of this, the fuel overflowing from the suction chamber 5 flows off through the through bore 40 and the groove 43 and exclusively through the first relief bore 44 and into the accumulator, the resistance to overflow is increased.Thus, the fuel pressure which prevails in the suction chamber 5, and which actuates the timing piston 24, will vary in accordance with the engine speed in the manner described above and, since the overflow restriction is greater, is maintained at a value which is higher than the predetermined value, so that the angle of advance of the instant of injection increases.
When current is not flowing through the coil 33 when the engine is operating under low load, the valve closure member 35 is in its bottom end position owing to the action of the spring 34.
Consequently, the fuel located in the suction chamber 5 flows off to the fuel tank 1 through the second relief bore 47 as well as through the first relief bore 44, and the pressure in the suction chamber 5 drops below the fixed value. Thus, the angle of advance of the instant of injection is decreased during operation under low load.
The instant of injection is also regulated in the above-described manner with respect to the other operating conditions of the engine.
As has been described in detail above, an optimum injection-timing characteristic corresponding to the operating conditions of the engine is also achieved by the present invention with respect to control factors other than the engine speed. Since dust or the like can be prevented from accumulating between the change-over valve and the bore, sliding movement of the change-over valve is not impaired and the pressure in the housing can be regulated far more accurately and thus the injection operation can be timed with greater accuracy.
Claims (6)
1. An injection-timing regulator for a fuet injection pump, comprising an injection-timing device which incorporates a timing piston subjected against the force of a spring to a pressure maintained in a suction chamber of a fuel injection pump in dependence upon engine speed, and a relief valve which leads from the suction chamber, the relief valve being a solenoid valve which is switchable in dependence upon at least one engine operating parameter and having a valve closure member in the form of a valve slide which is displaceable in a cylindrical valve housing bore open towards the suction chamber, which valve slide has a longitudinal bore permanently connected to the suction chamber and a reduced diameter portion which is located on the outer periphery and which forms between the valve slide and the cylindrical bore a space which on the one hand is permanently connected to the longitudinal bore by way of a radial bore and, on the other hand, is permanently connected to a first relief bore in the wall of the valve housing, and the longitudinal bore in the valve slide being connected to a second relief bore by way of an additional bore in the valve slide when the valve slide is in a first position.
2. An injection-timing regulator as claimed in claim 1, in which the valve slide is axially displaceable in the cylindrical bore by an electromagnet, against the force of a return spring, and when the magnet is deenergized, is held by the return spring against a fixed annular stop which is adjacent the suction chamber and which forms an axial boundary wall of the said space.
3. An injection-timing regulator as claimed in claim 2, in which the stop is a screw-threaded bush which is screwed into said cylindrical bore at the suction chamber end thereof.
4. An injection-timing regulator as claimed in claim 2 or 3, in which a radial groove is formed in that end face of the valve slide which faces the suction chamber.
5. An injection-timing regulator as claimed in any preceding claim, in which said first position of the valve slide is the position adopted when the solenoid valve is not energized.
6. An injection-timing regulator for a fuel injection pump, constructed and adapted to operate substantially as herein described with reference to and as illustrated in the drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10461879U JPS5622435U (en) | 1979-07-28 | 1979-07-28 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2056123A true GB2056123A (en) | 1981-03-11 |
| GB2056123B GB2056123B (en) | 1983-01-26 |
Family
ID=14385423
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8024590A Expired GB2056123B (en) | 1979-07-28 | 1980-07-28 | Injection-timing regulator for a fuel injection pump |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPS5622435U (en) |
| DE (1) | DE3026905A1 (en) |
| FR (1) | FR2462571A1 (en) |
| GB (1) | GB2056123B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3142145A1 (en) * | 1981-10-23 | 1983-07-21 | Bayerische Motoren Werke AG, 8000 München | Fuel injection pump for internal combustion engines |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4470397A (en) * | 1981-11-11 | 1984-09-11 | Lucas Industries Public Limited Company | Fuel injection pumping apparatus |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AT302726B (en) * | 1969-04-22 | 1972-10-25 | Bosch Gmbh Robert | Control device for fuel injection pumps |
| DE1932600C3 (en) * | 1969-06-27 | 1978-07-27 | Robert Bosch Gmbh, 7000 Stuttgart | Fuel injection system for compression ignition engines with a change in the start of injection |
| JPS5628804B2 (en) * | 1973-05-21 | 1981-07-04 | ||
| DE2503345C2 (en) * | 1975-01-28 | 1986-12-18 | Robert Bosch Gmbh, 7000 Stuttgart | Fuel injection pump for internal combustion engines |
| DE2648043C2 (en) * | 1976-10-23 | 1984-05-24 | Robert Bosch Gmbh, 7000 Stuttgart | Fuel injection pump for internal combustion engines |
-
1979
- 1979-07-28 JP JP10461879U patent/JPS5622435U/ja active Pending
-
1980
- 1980-07-16 DE DE19803026905 patent/DE3026905A1/en active Granted
- 1980-07-28 FR FR8016610A patent/FR2462571A1/en active Granted
- 1980-07-28 GB GB8024590A patent/GB2056123B/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3142145A1 (en) * | 1981-10-23 | 1983-07-21 | Bayerische Motoren Werke AG, 8000 München | Fuel injection pump for internal combustion engines |
Also Published As
| Publication number | Publication date |
|---|---|
| DE3026905C2 (en) | 1987-12-17 |
| GB2056123B (en) | 1983-01-26 |
| FR2462571B1 (en) | 1984-05-25 |
| FR2462571A1 (en) | 1981-02-13 |
| DE3026905A1 (en) | 1981-02-19 |
| JPS5622435U (en) | 1981-02-27 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19950728 |