JPH0587011A - Fuel injection pump for internal combustion engine - Google Patents

Abstract

PURPOSE: To eliminate the defects of conventional fuel injection pumps by effectively reducing the kinetic energy of the fuel jet of which the end of fuel discharge is controlled so as to avoid direct collision of the energy with the wall of a notch of a cylinder bushing. CONSTITUTION: In the region of a bore 14 for controlling the end of fuel discharge, a spill ring 15 loosely seated between two stops 20 (flange), 21 (fixed flange) surrounds a control slide 6. A spill space 18 is situated between the inner surface of the spill ring 15 and the outer surface of the slide 6 adjacent to the spill ring.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection pump for an internal combustion engine, in which at least one pump cylinder, which is constructed as a cylinder bush, is fixed in corresponding bores in the pump casing, and a reciprocating working stroke. At least one plunger reciprocally driven for rotation and pivoted for fuel control, and axially along the outer circumferential surface of the plunger for fuel control in a notch in the pump cylinder or pump casing. And a non-rotatably arranged at least one control slider, the control slider having a fuel discharge termination control hole oriented in a direction orthogonal to the plunger. Regarding things.

[0002]

2. Description of the Related Art In a fuel injection pump of this type controlled by a slider, the fuel injection amount and / or
Alternatively, the injection start time point is defined by the axial position of the control slider. Further, a configuration is known in which the control slider moves in the axial direction along the outer peripheral surface of the plunger and the rotation of the control slider affects the fuel control.

A groove (for example, an inclined groove) provided in the plunger by rotating the plunger by an appropriate adjusting device in the control slider which is prevented from rotating.
It is also known to perform injection strokes of different lengths and thus fuel injection amount control by means of and the notches formed in the groove.

At the end of the high-pressure injection (on the one hand, the end of fuel discharge in terms of time, and on the other hand, the end of the fuel discharge of the high-pressure feed in which the injection amount is defined), the plunger is provided in any case. The control opening is opened by a control slider, whereby fuel at very high pressure is injected from the pump working chamber through the load relief hole and the control opening into a notch in the cylinder bushing or pump casing. ..

A pressure of 1300 bar and higher is created in the pump working chamber, and a very high kinetic energy is created by controlling the end of the fuel injection flow after the fuel has been discharged by the control edge of the control slider. The energy imposes a heavy load on the material with which the fuel injection stream impinges, which, on the basis of the fast pressure conversion,
It is known that cavitation is eliminated in the constituent members.

The energy loss between the pump working chamber and the control point is relatively low. This is because the fuel discharge is abruptly interrupted from the fuel discharge end control (feed end) time point in order to ensure high-speed nozzle needle closure.

The fuel discharge end control hole is always arranged at the same position, and in order to avoid a cavitation phenomenon or an erosion phenomenon between the pump casing and the fuel discharge end control hole, it is made of hardened steel for collision protection. In-line injection pumps of the type provided with a spill ring are known (cf. DE-A-3136751). This known injection pump arrangement is not applicable to slider controlled pumps. because,
This is because the position of the fuel discharge end control hole changes at the same time as the axial position of the control slider on the outer peripheral surface of the plunger. The gap between the control slider and the wall of the notch is always connected to the suction chamber in a substantially squeezed state in order not to adversely affect the fuel control even during the suction stroke or the fuel discharge end control. Must have been done. The additional provision of the spill ring weakens the pump cylinder and undesirably enlarges the combustion chamber.

Further, the control slider is provided with a fuel discharge end control hole in the radial direction, and the fuel discharge end control hole is provided on the outer peripheral surface of the plunger, and the control groove as a control hole serves to effectively perform the fuel injection stroke. Fuel injection pumps of the type which are controlled to open after a certain period of time are also known (cf. DE-A 3540052). When the fuel discharge end control hole is controlled to be opened, the end-controlled fuel injection flow directly collides with the wall of the notch of the pump cylinder,
As the axial position of the control slider on the outer peripheral surface of the plunger changes, the end-controlled injection flow position also changes in relation to the location of the wall of the notch where the fuel injection flow collides. Due to the small gap width between the wall of the cutout and the opening of the fuel discharge termination control hole, the fuel injection flow penetrates into the gap from the wall of the cutout and is reflected, whereby the high energy is sucked into the pump casing. Reach the room. This type of fuel injection flow reflection is inconvenient. Because, the reflected jet, which still has a very high kinetic energy, impinges on the walls of the pump casing, which consist of a relatively soft material, for example aluminum, where cavitation phenomena and erosion damage occur. This will cause Similar damage can occur in the control member provided in the suction chamber.

Furthermore, a control slider, which is movable in the axial direction along the outer peripheral surface of the plunger for controlling the fuel injection start time, is provided in the cylinder bush, and the cylinder bush and the control slider are provided on both sides of the control slider. A cover member covering a radial annular gap at the inlet to the pump working chamber between which the fuel flow controlled by the end of fuel delivery and reflected by the side walls of the notch is reflected at least once more Energies are reduced, that is, fuel velocity is slowed, static pressure is increased, and cavitation bubbles are extinguished before or over fuel flow into the pump suction chamber above or below the cover member. Fuel injection pumps of the type described are also known (cf. DE-A 36 22 899). However, if the kinetic energy of the fuel injection flow controlled in the end of fuel discharge is reduced in this manner, this energy also collides directly with the wall of the notch of the cylinder bush, and thus the drawbacks described above. Will cause.

[0010]

The object of the present invention is therefore to improve a fuel injection pump of the type mentioned at the outset to avoid the disadvantages of the known device.

[0011]

According to the structure of the present invention to solve this problem, a spill ring arranged between two stoppers loosely surrounds the control slider in the range of the fuel discharge termination control hole. A spill space is provided between the inner surface of the spill ring and the outer surface of the control slider adjacent to the spill ring.

[0012]

According to the structure of the present invention, when the fuel discharge end control hole provided in the control slider is controlled to be opened, the fuel injection flowing out from the pump working chamber is accompanied by very high kinetic energy. The flow does not impinge directly on the wall of the cutout provided in the pump cylinder or pump casing, but is reflected by the loose arrangement of the spill ring on the control slider in the region of the fuel discharge end control hole, which is advantageous. As it flows through the outflow holes into the notch of the pump cylinder, it has the advantage that the jet flow energy is sufficiently extinguished and rendered harmless.

Further, according to the present invention, the spill space is formed by the hollow portion of the spill ring or the control slider formed between the outer peripheral surface of the control slider and the spill ring, and the fuel is sucked into the spill space. The advantage is that the kinetic energy is dissipated before it flows into the room.

According to another constituent feature of the present invention, the radial outflow hole provided on the outer peripheral surface of the spill ring is arranged so as to be displaced in the axial direction with respect to the axis of the fuel discharge end control hole of the control slider. Due to the controlled outflow of fuel via the outflow of fuel, these outflow holes are not covered or are only partially covered, whereby reflection or At least the change is guaranteed.

If the radially oriented fuel discharge end control holes are regularly arranged in the spill ring along one or two circumferential lines, the mode of operation of the arrangement according to the invention is further ensured. And to be stable. If the fuel discharge end control hole is arranged along two circumferential lines of the spill ring, the fuel discharge end control hole is preferably arranged at the center of these two circumferential lines.

According to another advantageous feature of the invention, in which the spill ring is arranged so as to be easily and naturally rotatable on the control slider, the fuel flowing from the outlet hole is always in the notch of the pump cylinder or pump casing. By avoiding hitting the same spot, damage due to cavitation is avoided.

According to another advantageous feature of the invention, the spill ring is simply axially retained on the control slider between two stops. One of the stoppers is formed as a flange portion on the control slider by a conventional technical method, for example, rotary cutting and grinding, and the other stopper is formed as a fixing ring, which fixing ring is formed on the control slider. It is included in the department.

According to another advantageous feature of the invention, a retaining disc is arranged between the spill ring and the fixing ring, which retaining disc is provided during the rotational movement of the spill ring. Ensures natural rotation without braking by the open end of.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENT In the embodiment shown in FIG. 1, a cylinder bushing 3 is fitted in a pump casing 1 (only partially shown) with a pump cylinder 2.
In the cylinder bush 3, the plunger 4 is reciprocally driven by means (not shown). A notch 5 formed as a blind hole is provided in the pump cylinder 2, and a control slider 6 is accommodated in the notch 5 so that the plunger 4 can slide axially along the outer peripheral surface. The pump cylinder 2, the cylinder bush 3 and the plunger 4 have a common axis line XX. The side wall of the notch 5 is provided with a twist prevention guide 7,
The anti-twist guide 7 ensures a twist-free axial movement.

Axial operation of the control slider 6 is carried out by means of a rotatable adjusting rod 9 which is shown schematically. The adjusting rod 9 is adapted to act on the pin 11 of the control slider 6 by suitable means.

In the fuel injection pump, a large number of pump elements (pump cylinder 2, cylinder bush 3, plunger 4) with such a control slider 6 are arranged, these pump elements being adjusted. It is commonly operated by the rod 9. The number of the entraining members 10 of the adjusting rod 9 corresponds to the number of the pump members. The adjusting rod 9 and the entrainment member 10 are arranged in the pump suction chamber 12, and the pump suction chamber 12 is supplied with fuel at a low pressure from a fuel container through a supply pump (not shown in detail). It has become.

The inlet 13 of the notch 5 of the pump cylinder 2 is directed towards the pump suction chamber 12, so that an open connection is formed between the notch 5 and the pump suction chamber 12.

The control slider 6 has a fuel discharge end control hole 1
4 is arranged, a spill ring 17 is provided in the range of the fuel discharge end control hole 14, and the spill ring 17 has a hollow portion 16 and the outer peripheral surface 17 of the control slider 6. Together they form the spill space 18. Outflow holes 19 are uniformly arranged on the outer circumference of the spill ring 15, and the axes of these outflow holes 19 are arranged so as to be displaced from the axis of the fuel discharge end control hole 14, so that the outflow holes 19 Does not make the fuel supply rate too high.

The spill ring 15 is slightly displaced by the control slider 6 so that one side surface abuts the flange 20 of the control slider 6 and the other side surface is fixed by a fixing ring 21 (fixed by a radial hollow portion 22). Control slider 6
It is configured to have a tolerance dimension such that the position at 1 is retained.

The control slider 6 provided so as to be axially movable along the plunger 4 has a fuel discharge end control hole 14
And a notch 24 provided on the outer peripheral surface of the plunger 4 via inclined grooves 23 provided in opposite directions to each other, and pumps via the lateral holes 25, 26 and the axial hole 27. It is connected to a work room (not shown).

In the second embodiment shown in FIG. 2, similarly to the first embodiment shown in FIG. 1, a pump casing 1 is provided with a pump cylinder 2 and a cylinder bush 3, and In the cylinder bush 3, the plunger 4 makes a reciprocating axial movement. An axially movable control slider 6 is received in the notch 5, and the control slider 6 is secured by an anti-twist guide (groove) 7 cooperating with the protrusion 8 so as not to be twisted. The anti-twist guide 7 and the protrusion 8 are shown as overlapping. The adjusting rod 9 is provided by the spherical end of the pin 30,
It is engaged with a correspondingly formed entrainment member 60 provided on the control slider 6. An adjusting rod 9 having one or more pins (if a large number of pump suction chambers are provided) is arranged in the pump suction chamber 12, said pump suction chamber 12 being provided in the notch 5 via an inlet 13. It is connected.

A plurality of fuel discharge end control holes 14 are provided in the control slider 6, and notches 16 and outflow holes 19 uniformly distributed on the outer periphery are formed on the fuel discharge end control holes 14. Is provided with a spill ring 15. The spill ring 15 is an outer peripheral surface 17 of the control slider 6.
The spill space 18 is formed in cooperation with. Since the axis of the outflow hole 19 is arranged so as to be offset from the axis of the fuel discharge end control hole 14, the fuel discharge end control hole 14 is arranged.
The unintentional outflow of fuel into the notch 5 is avoided.

The spill ring 14 which can be easily rotated by the control slider 6 has one side in contact with the flange 20 of the control slider 6 and the other side in contact with the holding disk 28.
The holding disc 6 is located in the hollow 22 of the control slider 6.

The control slider 6 or the fuel discharge end control hole 14 thereof is connected to the notch 24 via the inclined groove 23 arranged in the plunger 4 in the diametrically opposite directions, and the lateral hole 25 of the plunger 4 is connected. , 26 and an axial hole 27 are connected to the pump working chamber 29.

The embodiment shown in FIG. 2 and the embodiment shown in FIG. 1 are such that the control slider 6 and the adjusting rod 9 are arranged and connected, and that the holding disk 28 is fitted therein.
And the pump work room configuration is different. However, the mode of operation of the embodiment shown in FIGS. 1 and 2 is the same. A cam shaft (not shown) causes the plunger 4 to reciprocate against the spring force of a spring (not shown). The plunger 4 is mounted on the cylinder bush 3 by a known adjusting device.
Can be staggered within. The predetermined spacing of the inclined groove 23 from the fuel discharge end control hole 14 differs depending on the respective rotational position of the plunger 4 with respect to the inclined groove 23 and the cutout 24 formed in the control slider 6, and this is the same. Corresponding to injection strokes of different lengths and thus injection times.

Another schematically illustrated device for controlling fuel is provided on the pins 11, 30 of the control slider 6 for axially displacing the control slider 6 along the outer peripheral surface of the plunger 4. There is an adjusting rod 9 with an entrainment member 10, 60.

Pump working chamber 29 not shown in FIG.
(See FIG. 2), the lateral holes 25, 26 and the axial hole 2
Fuel is supplied via a pump suction chamber 12 which also surrounds the control slider 6 during the suction stroke. During the compression stroke, fuel is guided back into the pump suction chamber 12 through the axial hole 27, the lateral holes 25, 26 and the inclined groove 23 until the lateral holes 25, 26 enter the control slider 6. It The actual high pressure injection of the internal combustion engine is then started, independent of the stroke length of the control slider 6 along the plunger 4. This injection is interrupted when the inclined groove 23 is controlled to be opened by the fuel discharge end control hole 14 during the supply stroke. At this moment, when fuel under high pressure in the pump working chamber enters the spill space 18 through the axial hole 27, the lateral hole 25, the inclined groove 23 and the fuel discharge end control hole 14, the fuel flow flows out here. The outflow hole 1 is reflected or bent by the position of the hole 19 being displaced.
It is guided back through the notch 5 into the pump suction chamber 12 via 9, at which time the high pressure in the pump working chamber substantially eliminates the kinetic energy still present in the fuel.

In the embodiment of FIG. 3, a pump cylinder 32 is fitted in a pump casing 31, which is only partially shown, in which a plunger 33 is reciprocated by means not shown. It can be replaced. Notch 3 in pump cylinder 32
4 is provided, and the plunger 33 is provided in the notch 32.
Control slider 35 that is axially movable along the outer peripheral surface of the
Is accepted. A guide pin 36 is inserted into the side wall of the notch 34 formed in the pump cylinder 32.
The guide pin 36 is engaged in the groove 37 of the control slider 35, so that the control slider 35 is moved to the pump cylinder 3
2, the plunger 33 and the control slider 35 are secured against the rotational movement about the common axis Y-Y, but the axial movement movement along the outer peripheral surface of the plunger 33 is allowed. .. The axial movement of the control slider 35 is adapted to be carried out by an adjusting rod 38 which engages in a slit 41 of the control slider 35 with a spherical pin 39 attached to an adjusting screw 40, The control slider 35 is moved along the plunger 33 according to a desired injection start time point. Generally, in a fuel injection pump, a large number of such pump members (pump cylinder 32, plunger 33) having a control slider 35 are arranged in a row in a pump casing 31. These pump members (32,
33) is commonly operated by the adjusting rod 38. The number of adjusting screws 40 corresponds to the number of pump members respectively assigned to these adjusting screws 40. An adjusting rod 38 with an adjusting screw 40 is arranged in a pump suction chamber 42 so that fuel can be supplied to the pump suction chamber 42 at low pressure from a fuel container (not shown) via a feed pump. It has become. The inlet 43 connects the notch 34 to the pump suction chamber 42, so that here an always open connection is formed.

The control slider 35 is provided with a fuel discharge end control hole 44 which intersects at right angles with one axis.
A spill ring 45 surrounds the control slider 35 in the center of the range of the fuel discharge end control hole 44. The control slider 35 is provided with a hollow portion 46, and the hollow portion 46 cooperates with the outer surface 47 of the adjacent control slider 35 to form a spill space 48. The outer circumference of the spill ring 45 is at least two radially oriented
Rows of outflow holes 49 are provided and these outflow holes 49
With respect to the axis line of the fuel discharge end control hole 44, the axis of is directly located at the center of the two rows of the outflow holes 49 so that the range of direct outflow from the fuel discharge end control hole 44 is abutted.
They are arranged in a staggered manner. The dimensions of the spill ring 45 are
The spill ring 45 is set so as to be loosely rotatable along the outer peripheral surface of the control slider 35. The control slider 35 is provided with a hollow portion 50 having a flange 51, and the spill ring 45 is attached to the hollow portion 50.
One side is on the other side of the spill ring 45
The position is secured by the fixing ring 52 which is also arranged in the hollow portion 53 of the control slider 35.

The plunger 33 is provided with an axial hole 54, which intersects the inclined groove 56 provided on the opposite side through a lateral hole 55. Another lateral hole 57 is provided in the plunger 33 at approximately the end of the axial hole 54. As a result, the pump working chamber 58 has the axial hole 54, the lateral hole 55 having the inclined groove 56, the lateral hole 57, the fuel discharge end control hole 44, the outflow hole 49, and the notch 3.
4 and the inlet 43 to the pump working chamber 42.

The embodiment shown in FIG. 3 has a working style similar to that of the embodiment shown in FIGS. 1 and 2, but the construction of the spill ring 45 is different. It has two rows of outflow holes 49 along two circumferential lines. Further, the arrangement of the fuel discharge end control hole 44 is also different. The type of connection between the adjusting rod 38 and the control slider 35 is also different from that of the embodiment of FIG.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a fuel injection pump according to a first embodiment of the present invention.

FIG. 2 is a partial sectional view of a fuel injection pump according to a second embodiment of the present invention.

FIG. 3 is a partial sectional view of a fuel injection pump according to a third embodiment of the present invention.

[Explanation of symbols]

1,31 Pump casing, 2,32 Pump cylinder, 3 Cylinder bush, 4,33 Plunger, 5,34 Notch, 6,35 Control slider,
7 Anti-twist guide, 8 Projection part, 9,38 Adjustment rod, 10,60 Entrainment member, 11,30,3
9 pin, 12,42 Pump suction chamber, 13,43
Inlet, 14,44 Fuel discharge end control hole, 15,
45 spill ring, 16,46,53 hollow part, 17 outer peripheral surface, 18,48 spill space,
19,49 Outflow hole, 20,51 Flange, 2
1,52 Fixing ring, 22 Radial hollow part, 23,56 Inclined groove, 24 Notch, 25,2
6,55,57 lateral holes, 27,54 axial holes,
28 holding disk, 29 pump working chamber, 36 guide pin, 37 groove, 40 adjusting screw, 41 slit, 47 outer surface, 50 hollowed part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Anton Pitsinger, Austria Graz am Schjurgätse 29

Claims (9)

[Claims] 1. A fuel injection pump for an internal combustion engine, comprising at least one pump cylinder, which is fixed in a corresponding bore in the pump casing, is designed as a cylinder bush and is reciprocally driven for a reciprocating work stroke. And at least one plunger pivoted for fuel control and axially movable and non-rotatable in the notch of the pump cylinder or pump casing along the outer peripheral surface of the plunger for fuel control. At least one control slider disposed in the fuel discharge end control hole, the control slider having a fuel discharge end control hole oriented in a direction orthogonal to the plunger. A spill ring (1) arranged between two stoppers (20, 21; 51, 52) in the area of the end control hole (14). 5, 45) loosely surrounds the control slider (6, 35), the inner surface of the spill ring (15, 45) and the outer surface of the control slider (6, 35) adjacent to the spill ring. A fuel injection pump for an internal combustion engine, characterized in that a spill space (18, 48) is provided therebetween. 2. The spill ring (15, 45) is provided with an outflow hole (19, 49) directed in a radial direction, and the outflow hole (19, 49) is a fuel discharge end control hole (1).
4,44) arranged offset from each other.
The fuel injection pump described. 3. The fuel injection pump according to claim 2, wherein the outflow holes (19, 49) are arranged along at least one circumferential line of the spill ring (15, 45). 4. Outflow holes (19, 49) are arranged along two circumferential lines of the spill ring (15, 45), and fuel discharge end control holes (14, 44) are said outflow holes (19). , 49) disposed approximately midway between the two circumferential lines of the fuel injection pump of claim 3. 5. A fuel injection pump according to claim 4, wherein the spill ring (15, 45) is rotatably supported by the control slider (6, 35). 6. The spill ring (15, 45) and / or the control slider (6, 35) each have a hollow (53) on their opposite faces, the hollow (53) The width dimension is this hollow part (53)
6. The size is set such that the opening of the outflow hole (19, 49) on the piston side is located in the range.
The fuel injection pump according to any one of items 1 to 7. 7. The flange (20, 20) on the side of the control slider (6, 35) facing the spill ring (15, 45).
51) Fuel injection pump according to claim 1, characterized in that it is provided with (51). 8. Radial hollow for a locking ring (21, 52) on the control slider (6, 35) on the side of the spill ring (15, 45) opposite the flange (20, 51). Claim 1 provided with (22).
The fuel injection pump described. 9. Fuel injection pump according to claim 8, characterized in that a holding disc (28) is arranged between the spill ring (15, 45) and the fixing ring (21).