JPH01253561A - Fuel injection pump for internal combustion engine - Google Patents

Abstract

PURPOSE: To correctly control fuel injection rate by defining a pump working chamber between top end of a pump piston inserted in a guide cylinder and an axially displaceable piston, and arranging a ring slider in the piston that is projective from the guide cylinder. CONSTITUTION: A step type pump piston 4 is inserted into a guide cylinder 2 being a distributor, a sleeve 21 is slidably outer inserted in a top end of a part 7 having a small diameter, and a cylinder slider 44 is slidably outer inserted in a part having a big diameter and outward projective from the guider cylinder 2 for opening or closing an overflow transverse hole 42. And a piston body 24 is inserted from the other end into the sleeve 21, a pump working chamber 25 is defined between the end face of the piston part 7 and the sleeve. Position of the piston body 24 is limited by a stopper pin 12 screwed on a closing part 10, a control piston 18 defining a pressure control chamber 32 and a pressure release chamber 33 is installed in the stopper pin 12, and the pressure control chamber 32 is connected to an inner chamber 38 by a guide pipe 40, having the pressure in connection with the rotation number.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The invention comprises a reciprocating and rotationally driven pump piston, which is constructed as a stepped piston, with a larger diameter piston serving as a distributor. A sleeve is slidably arranged at the end of the smaller diameter piston part of the pump piston projecting from the guide cylinder, and a sleeve is slidably arranged in the bore of the sleeve. from one side and a plug protrude forming a pump working chamber, the plug protruding from the other side forming a pump working chamber, the plug protruding on the side which is outside the hole to adjust I'tf.
It is in contact with the stopper pin that can be
extends adjustably through a closure part of the fuel injection pump casing coaxially with respect to the pump piston and has a shoulder facing towards the closure part for receiving the sleeve;
A control piston sealed in a cylinder closed towards the guide cylinder on the one hand and by the closing part on the other hand is slidable between the shoulder and the closing part, and the control piston is moved towards the stop. A pin passes through the control piston, the control piston having a shoulder on the side facing the sleeve, against which the sleeve is abutted by a spring held in place, and the control piston is connected to the pump of the cylinder. A pressure relief chamber formed by the control piston is connected to the tank through a pressure relief conduit 7ζ, and a control pressure chamber formed on the closing side by the control piston in the cylinder is connected via the pressure conduit to the pump piston is connected to a pressure source having a pressure of
A longitudinal passage extends from the end face which limits the entire pump working chamber, the longitudinal passage being connected to a control opening in the circumferential surface of the pump piston, and the connection between the control opening and the pressure relief chamber being formed in the sleeve. A filling channel, which is controllable by a control lip and which opens in the region of the guide cylinder on the circumference of the piston part serving as a distributor, can be connected to the longitudinal channel for supplying fuel during the suction stroke of the pump piston. one of the plurality of discharge passages distributed around the bonnoviston and extending from the guide cylinder and connectable with an injection point in the internal combustion engine is arranged such that one of the plurality of discharge passages distributed around the bonnoviston is connected to the pump in the region of the guide cylinder during the discharge stroke of the bonnoviston. The present invention relates to an internal combustion horizontally-opening fuel injection pump having a distribution opening provided on the circumferential surface of a piston that can be connected to the vertical passage.

BACKGROUND OF THE INVENTION In known fuel injection pumps of the type mentioned above, the supply of fuel to the pump working chamber takes place via a variable inlet throttle which is arranged in the filling channel and controls the amount of fuel injected per delivery stroke of the pump piston. . Therefore, in part-load operation of the internal combustion engine in question, the pump working chamber is in the suction stroke! Since the tank is no longer completely filled with fuel, suction forces act on the freely movable plug body and the control sleeve in this known fuel injection pump.

This results in undesirable wear at the point of contact of the stopper against the stopper pin.

By controlling the opening of the A port first, the effective discharge stroke of the pump piston is shortened.
As soon as pressure begins to build up in the control pressure chamber, the starting fuel quantity is controlled to decrease, but in this known fuel injection pump, the discharge characteristics of the fuel injection pump 0, especially during full-load operation, reduce the required fuel quantity of the internal combustion engine. cannot be adapted to.

OBJECTS OF THE INVENTION It is an object of the invention to improve a fuel injection pump of the type mentioned at the outset, so that the fuel injection quantity can be precisely controlled.

Means for Solving the Problems The object and solution of the invention is that the pump piston projects on the drive side from the guide cylinder into an interior chamber filled with fuel, in which the pump piston A ring slider adjustable by a fuel injection amount regulator is disposed around the circumference of the cylinder, and the ring slider controls the exit portion of the longitudinal passage with respect to the inner chamber by means of a control edge, and controls the flow of air through the control opening. It is provided that the effective point of the open leg of the pump working chamber and the limiting edges on the sleeve controlling the control opening are varied as a function of the rotational speed.

Effects of the Invention In the fuel injection pump of the present invention, accurate control of the fuel injection liquid is performed by ring slider control. In this case, the effective delivery stroke of the pump piston can be adjusted geometrically with respect to the fuel liquid column under constant delivery pressure.

Due to the constant end point of the effective delivery stroke of the pump piston, it is now possible to adapt the full-load injection quantity to the requirements of the internal combustion engine in relation to the power output. In this case, for full negative operation, if the configuration is as set forth in claim 2, accurate reduction control of the full load injection amount can be obtained when the maximum rotational speed is reached. This is because, in order to carry out a reduction control, the ring slider must first travel a predetermined initial stroke before the control edge of the ring slider becomes effective, so that the ring slider adjustment g! This is because the effects of vibration or hysteresis of the fth device no longer occur.

The rotational speed-related correction is achieved in an incremental manner by the throttle effect of the outlet cross-section and the rotational speed-related effect. In this case, for example, the flow cross section of the control opening can be increased towards the drive side of the pump piston by varying its width and/or depth, as described in claim 1A5.

Correct adaptation to this is advantageously achieved in that the spring means has a spring characteristic as defined in claim 6. An always precise abutment of the plug on the stopper pin is provided in claim 7 in addition to the fact that the pump working chamber is filled without throttling during each suction stroke of the pump piston, as already stated in claim 1. This is achieved by providing a retaining spring. This avoids undesirable wear or irregularities in the injection cap or drifts in the fuel injection quantity.

The invention will now be explained with reference to the drawings.

A cylinder bushing 3 is arranged in a casing 1 of a fuel injection pump, and a pump piston 4 is arranged in the cylinder bushing 3. This pump piston 4 is given both reciprocating motion and rotational motion by means not shown. The pump piston 4 is constructed as a stepped piston, the larger diameter piston part 6 being guided in the guide cylinder 2 as a distributor. The piston part 7 with the smaller diameter also protrudes from the guide cylinder 2 and is connected to the cylinder 9.
It's going inside.

The cylinder 9 is connected on its end side to a cylinder bush 3 in the housing 1 of the fuel injection pump. On the side opposite the cylinder bush 3, the cylinder 9 is tightly closed with a closing part 10.

The closing part 10 is screwed into the housing 1 coaxially with the axis of the pump piston. A stopper pin 12 likewise extends coaxially with the axis of the pump piston 4 through the closing part 10 . This stop pin 12 is held in the closure part 10 by a thread 13, is adjustable and can be fixed from the outside by means of a locking nut 14. The cylinder 9 is sealed to the outside by a sealing ring 15 on the piston/12. The stopper pin 12 has a closing part 1 at its end projecting into the cylinder 9.
It has a collar 16 with a shoulder 17 facing o. Between the core layer 17 and the closure part 7) 10, the stopper pin 12 passes through a bowl-shaped control piston 18, which presses the stopper pin 12 by the value X between the shoulder 17 and the closure part 1o. can be slid along. The surfaces of the control piston 18 are tightly guided within the cylinder 9. The control piston 18 surrounds a sleeve 21 with a circumferential wall 19, which sleeve 21 is slidable in a bore 22 over the small diameter piston part 7. A plug body 24 projects into the hole 22 from the side opposite to the side into which the piston portion 7 enters. The plug 24, like the piston/part 7, is tightly guided in the bore 22.

A pump working chamber 25 is formed between the end face of the plug body 24 and the end face of the piston portion 7 . In this case, the plug body 24 is supported by a push spring 27, that is, a push spring 28 acting on a spring receiver 28 supported by the spring 21 and connected to the plug body 24.
7, it is crimped to the end face of the stopper pipe/12.

This push spring 27 acts as a holding spring.

Furthermore, a pressure spring 30 acts on the sleeve 21 and serves as a starting spring. The push spring 30 is fixedly supported on the end face of the cylinder bush 3. This pressure spring 30 keeps the sleeve 21 against a shoulder 31 formed on the control piston 18 . The control piston 18 connects the cylinder 9 formed between the closing part 10 and the cylinder bush 3 with a control pressure chamber 32 between the control piston 18 and the closing part 10 via a pressure relief conduit 34, for example. It is divided into a pressure relief chamber 33 connected to the suction side of the fuel feed pump 36. fuel feed pump 3
6 is the inner chamber 3 of the fuel injection pump for all fuel from the fuel tank 37
Transfer to 8. In this case, the fuel feed pump is driven coaxially to the drive speed of the fuel injection pump and cooperates with the pressure limiting valve 39 to create a speed-dependent pressure in the interior chamber 28 in a known manner. . This inner chamber 28 is a pressure conduit 4
0 to the control pressure chamber 32 at all times.

From the end face of the piston part 7 with the smaller diameter, a longitudinal channel 41 extends through the pump piston and through a transverse bore 42 into the part of the piston part 6 with the larger diameter which projects into the interior chamber 38 . It is open on the circumference. The outlet 45 of the transverse hole (7) at the outlet of the longitudinal passage 41 is controlled by a control lip 43 arranged on a ring slide 44 that can be slid tightly on the piston part 6 of larger diameter. In this case, the ring slider 44 constitutes a metering mechanism of the fuel injection pump,
Adjustment lever 4 is adjusted by a known adjuster (not shown).
7. The higher the ring slider 44 is adjusted, the longer the effective piston discharge stroke is until the outlet 45 opens in the illustrated discharge end timing adjusting device. In this case, the pump working chamber 25 is the vertical passage 4
1 into the internal chamber 38.

For filling the pump working chamber, a radial bore 48 branches off from the longitudinal channel 41 in the region of the guide cylinder 2 into a filling opening 50 provided around the circumference of the piston part 6 with the larger diameter. This filling opening 50 is brought into alignment with a filling channel 51 opening into the guide cylinder by rotation of the pump piston during the suction stroke of the pump piston.

This filling passage 51 branches off from the pressure conduit 40 and can be shut off by a shutoff solenoid valve 53 . Instead of one filling opening 50 and one filling channel opening, it is also possible to have a plurality of these distributed over the circumference of the pump piston.

Furthermore, a radial bore 54 branches off from the longitudinal channel 41 around the pump piston part 6 with the larger diameter. During the discharge stroke of each pump piston, this distribution opening is alternately connected to one of a plurality of pressure passages 57 which are distributed on the circumference of the pump piston and which also branch out into the guide cylinder 2 . The pressure channels 57 each lead to an injection valve 58 of the internal combustion engine.

In this case, the pressure passages 57 each incorporate a pressure valve of a known structure, and during the injection pause period, each pressure passage 57 is connected by the pressure relief passage 59 between the pressure valve and the opening in the guide cylinder. The pressure is released alternately to a constant pressure level.

Further, a horizontal hole 61 branches off from the vertical passage 41, and the horizontal hole 61 is connected to the pump piston portion 7 with a smaller diameter.
It is connected with a control opening 62 provided on the surface of the part guided in the bore 22 . The control opening 62 is a ring groove in the illustrated embodiment, which is aligned with the opening 63 of the passage 64 through the wall of the sleeve 21 during the pump piston stroke. The openings 63 each have an irregular shape and decrease in width towards the cylinder bush 3, as shown in FIG. Alternatively or additionally, the circular outlet opening of the conventional bore has a laterally enlarged cut so that the depth and thus the outflow cross section partially formed therein is reduced to the cylinder bush 3. It can also be made to decrease in the opposite direction. With this type of ring groove 62
When the opening 63 and the opening 63 begin to overlap, a small outflow cross section is first controlled to open, and this outflow cross section gradually becomes larger as the discharge stroke of the pump piston progresses. As a result, during the delivery stroke of the pump piston, the pump working chamber is initially depressurized via the channel 63 in a throttled manner. The throttling effect increases in a known manner with respect to the quantity flowing out of the pump working chamber as the rotational speed increases.

This is because the time available for throttled outflow decreases as the number of cycles increases.

The above-mentioned fuel injection pump is operated as follows: When the pump piston 4 driven by a means not shown moves during the suction stroke and the Ifr solenoid valve 53 fully opens the filling passage, the pump operation is interrupted. The chamber is completely filled with fuel on each suction stroke of the piston pump. In this case, the filling opening 50
is connected to the filling passage 51. During the discharge stroke following the suction stroke, the distribution opening 56 is connected to one of the pressure channels 57 and the connection of the filling opening to the filling channel is interrupted. When the ring slider 44 is in the part-load position, the outlet 45 is closed and the control piston 18 rests against the shoulder 17;
With the control sleeve 21 in contact with the shoulder 31, the control opening 6
2 is closed. A high pressure is therefore built up in the pump working chamber 25, which pressure is transmitted via the vertical channel 41 and one of the pressure channels 57 to the injection valve 58, opening it and starting the fuel injection. When the internal combustion engine is in the partial load range, as the discharge progresses further, the outlet 45 is controlled by the control edge 43 of the ring slider 44.
It is opened before the control opening 62 is opened. From this point on, the remaining fuel discharged by the pump piston will be transferred to the inner chamber 38.
and the injection is terminated. However, when the internal combustion engine is in the full load position, the control opening 62 is connected with the opening 63 before the outlet 45 opens, so that the pump working chamber is also relieved towards the pressure relief chamber 33 and the injection is terminated. . Therefore, if the position of the control piston 18 with respect to the shoulder 1T or the position of the sleeve 21 with respect to the control piston is constant, a constant discharge end timing can be obtained.

This has the advantage that the ring slide 44 can be moved further towards the cylinder bush 3 than would be expected to be necessary to adjust the full-load injection quantity. As a result, when the injection amount is controlled to decrease, the control opening 62 is controlled, the output port 45 is opened with the drowsiness cut out, and the fuel injection pump is controlled to decrease to zero while the ring slider 44 is moving. The ring slider 44 has to advance a predetermined initial stroke further toward the cylinder bushing 3 until the cylinder bushing 3 is reached. In this case, the rocking motion of the ring slider caused by the injection amount reduction control process of the regulator at the injection amount reduction control point is prevented from acting on the start of the injection layer reduction control,
The advantage is that the full load power is fully maintained up to the desired injection rate reduction control point. Furthermore, the influence of hysteresis is also eliminated in this case.

Internal combustion) jump; and over-starting when starting, obtaining IIT is achieved by the following action: Before starting, the internal combustion chamber 3
The pressure at 8 is at a very low level, so that the control piston 18 rests against the closing part 10 under the action of the pressure spring 30.

That is, the necessary pressure is insufficient in the control pressure chamber 32. The sleeve 21 follows the control piston 18 so that the opening [ ] 63 is moved such that the control opening 62 does not overlap the opening 63 during the delivery stroke of the pump piston, or only does so at a very late stage. Accordingly, the fuel injection amount exceeding the full load injection amount is injected per discharge stroke of the pump piston at z5. Since this fuel injection quantity is achieved after the full-load injection quantity, no advance adjustment of the injection start timing is carried out in relation to the injection quantity at start-up.

When the internal combustion engine starts to rotate, a pressure builds up in the internal chamber 38, which forces the control piston 1 to move by the value X until it rests on the shoulder 17, bringing the opening 63 into its normal full load position.

By adjusting the stopper bin, the "II& and thus the starting overload is regulated. As already mentioned, the total load contribution can be additionally varied by the action of the throttling effect due to the shape of the opening 63. In this way Of course, a similar shape can also be provided in the control opening 62.

Another possibility of unliving control is shown in the variant embodiment of FIG. In this case shoulder 17 and control piston 18
An Angleich spring 66, which is preferably designed as a disc spring, is provided between. Furthermore, in this case, a seal ring 68 is shown in the outer ring groove 67 of the collar 16.

The seal ring 68 is fixed in the outer ring groove 67 and slides on the inside of the cylindrical portion 69 of the control piston 18!
Young Ritsu, '7°? have. In this embodiment, the control piston contacts the Angleich spring 66 only after it has overcome the starting spring 30. As the rotational speed continues to increase, the control pressure in the control pressure chamber 32 is increased, and the underground spring 66 is gradually tightened λt, so that the full-load injection quantity is reduced to the positive force of the underground angle 11.

An alternative configuration to the configuration in FIG. 6 is shown in FIG. 4. In FIG. 4, the collar 16 in FIG.
' and is screwed onto the end of the stopper pin. Other points correspond to the configuration shown in FIG.

In contrast to the previously described embodiments, the control pressure chamber may be located at the pump, drive #0IIJ of the control piston, and a starting spring 30 may be arranged between the control piston and the closing part 10. In this case, there is an overstart, and V! In order to achieve the II quantity, the end face of the sleeve on the pump drive side forms a control edge 63 and can take the place of a passage 64. In this case, start!
#jJ excess amount is placed before the full load injection amount. At the same time, the Angleich spring arranged between the closing part 10 and the control piston 18 provides a positive Angleich for the full-load injection quantity.

[Brief explanation of the drawing]

drawing! l-1: One embodiment of the present invention together with modified embodiments ('
1 is an analytical view of the fuel J-mura pump shown in outline 10, FIG. 2 is a detailed view of a portion of FIG. 1, and FIG. 6 is a detailed view of a portion of FIG. A detailed view of the part, FIG. 4, corresponds to FIG. 6 of a modified embodiment of the invention. 1...Casing, 2...Guide cylinder, 3...
Cylinder bushing, 4...Pump piston, 6...
Piston part, 7... Piston part, 9... Cylinder, 10... Closing part, 12... Stoppavi/, 1
3... Screw thread, 14... Locking nut, 15... Seal ring, 16... Collar, 1T... Shoulder, 18...
- Control piston, 19... Peripheral wall, 21... Sleeve, 22... Hole, 24... Plug, 25... Pump work chamber, 27... Pressing spring, 28... Spring holder , 30・
...Press spring, 31...Shoulder, 32...Control pressure chamber,
33... Pressure relief chamber, 34... Pressure relief conduit, 36... Fuel feed pump, 31... Fuel tank, 38...
Inner chamber, 39... Pressure control valve, 40... Pressure conduit, 4
1... Vertical passage, 42... Horizontal hole, 43... Control edge,
44...Ring slider, 45...Exit, 47...
・Adjustment lever, 48...Radius hole, 50...Filling opening, 51...Filling passage, 53...G analysis, 54...
Radial hole, 56...Distribution opening, 57...Pressure passage, 58
...Injection valve, 59...Pressure relief groove, 61...Horizontal hole, 6
2... Control opening, 63... Opening, 64... Passage,
66...Underground 11 Iwa! 67...Outer ring groove, 68...Seal ring, 69...Cylindrical part.

Claims (1)

[Claims] 1. It has a reciprocating and rotationally driven pump piston (4), which is configured as a stepped piston and which is connected to a guide cylinder (6) with its larger diameter piston part (6), which acts as a distributor. 2), and a sleeve (21) is slidably arranged at the end of the smaller diameter piston part (7) of said pump piston (4) which projects from said guide cylinder (2). The pump piston (4) is inserted into the hole (22) of the sleeve (21) from one side, and the plug (24) is inserted from the other side.
forms a pump working chamber (25) and projects into it, the stopper (24) abuts on the side outside said hole (22) an adjustable stopper pin (12), said stopper pin ( 12) is the closed part of the fuel injection pump casing (
10) coaxially adjustable with respect to said pump piston (4) and extending towards said closing part (10).
7) in a cylinder (9) receiving said sleeve (21) and closed on the one hand towards said guide cylinder (2) and on the other hand by said closing part (10). A control piston (18) sealed to the stopper pin (18) is slidable between said shoulder (17) and said closure part (10), and said control piston (18) is sealed to said stopper pin (
12) passing through, said control piston (18) having a shoulder (31) on the side facing said sleeve (21), on which shoulder (31) said sleeve (21) is supported in position. A pressure relief chamber (33) formed by the control piston (18) on the pump side of the cylinder (9) is connected to the tank by a pressure relief conduit (34). and a control pressure chamber (32) formed on the closed side by the control piston (18) in said cylinder (9) is connected via a pressure line (40) to a pressure source with a pressure dependent on the rotational speed. A vertical passageway (41) extends from an end surface of the pump piston (4) that limits the pump working chamber (25).
) is a control opening (62) in the circumferential surface of the pump piston.
), the connection between said control opening (62) and said pressure relief chamber (33) can be controlled by means of a control lip (63) in said sleeve (21), said piston part ( 6) is provided with a filling passage (51) that opens in the area of the guide cylinder (2).
) are connectable with the longitudinal passage (41) for supplying fuel during the suction stroke of the pump piston (4) and are distributed around the pump piston (4) to supply fuel to the guide cylinder (2). One of the plurality of discharge passages (57) extending from and connectable with an injection point in the internal combustion engine is arranged in the region of the guide cylinder (2) of the pump piston (4) during the discharge stroke of the pump piston (4). In a fuel injection pump for an internal combustion engine, the pump piston (4) is connected on the drive side to the guide cylinder (2 ) into the inner chamber (38) filled with fuel, and a ring slider (44), which is adjustable by a fuel injection amount regulator (47), is provided on the circumferential surface of the pump piston (4) at the projecting part. ) is arranged, and the ring slider (44)
is a control edge (43) that connects the longitudinal passageway (41) to the inner chamber (38).
) controls the outlet (45) of the control opening (62
) and the control edge (63) in the sleeve (21) controlling the control opening (62) are varied in relation to the rotational speed. A fuel injection pump for an internal combustion engine. 2. When the ring slider (44) is in the full load position, the pump working chamber (25) is located in the longitudinal passage (
2. The fuel injection according to claim 1, wherein the pressure is released by controlling the opening of the control opening (62) by a control edge (43) in the ring slider (44) before controlling the opening of the outlet (45) of the ring slider (44). pump. 3. The effective point of the opening control of the pump working chamber (25) via the control opening (62) becomes progressively smaller in relation to the pump piston stroke relative to the opening control point of the control opening (62) by means of the control edge (63). 3. The fuel injection pump as claimed in claim 1, wherein the pump is controlled by a throttled outlet cross section. 4. Fuel injection pump according to claim 3, characterized in that the control edge (63) is a limiting edge of the opening of a passage (64) through the wall of the sleeve (21). 5. said opening or said control opening (62) has an outlet cross-section of varying depth and/or width that increases as the mutual overlap increases during the discharge stroke of said pump piston (4); The fuel injection pump according to claim 4. 6. Fuel injection pump according to claim 1 or 2, characterized in that spring means (66) are provided between a shoulder (17) on the stopper pin (12) and the control piston (18). 7. Claims 1 to 6, wherein a retaining spring (27) is arranged under tension between the sleeve (21) and the plug (24) protruding from the hole (22).
The fuel injection pump according to any one of the preceding items. 8. The shoulder (17) of the stopper pin (12) is constituted by a collar (16, 16');
An outer ring groove (67) is provided on the circumferential surface of the outer ring groove (67), and a seal ring (68) is fitted into the outer ring groove (67).
Said sealing ring (68) forms a cylindrical portion (6) of said control piston (18) surrounding said collar (16, 16').
9) The fuel injection pump according to any one of claims 1 to 7, which slides along the fuel injection pump.