EP0273225A2 - Fuel injection pump for internal-combustion engines - Google Patents

Abstract

A fuel injection pump of the distributor injection pump type is proposed in which, in order to achieve low injection rates in the idling range on the pump piston, longitudinal slots or longitudinal channels (55) are provided in the lateral surface corresponding to the number of delivery strokes of the pump piston, which are always provided with an annular groove (54) on the adjacent ring slide (18 ), the quantity adjustment element of the fuel injection pump are connected and they come into rotation with a control opening (58) during the delivery stroke of the pump piston (4), via which the pump work space can be relieved if a second outlet opening (52) is used during the pump piston stroke movement the discharge duct (14), which is connected to the pump work chamber and runs in the pump piston, comes into contact with the annular groove (54). From this point, the delivery rate of the pump piston is reduced in order to achieve quiet running of the internal combustion engine by the outflow rate of the delivered fuel into the suction chamber (7), which flow rate is determined via a throttle (51). By turning the ring slide (18), the control opening (58) can be brought out of the working area of the longitudinal channels (55) and the silent running device can be switched off.

Description

State of the art

The invention is based on a fuel injection pump according to the preamble of the main claim. In a fuel injection pump of this type known from DE-OS 32 13 724, the pump piston has, as a relief channel, an axial blind bore extending from the pump working space, from which a transverse channel branches off to two first outlet openings and furthermore a radial channel branches off to a second outlet opening. This outlet opening is offset from the first outlet openings on the pump drive side and works together with a radial bore arranged in the ring slide, via which the connection to the relief chamber can be established. In the known fuel injection pump, the radial bore is arranged in such a way that the second outlet opening in a ring slide position corresponds to the low-load operating range during the pump piston delivery stroke, while in the full-load range the second outlet opening does not come into contact with the radial bore. This device serves to allow only a part of the delivery strokes of the pump piston to take effect in the low-load range, and accordingly several radial bores are provided around the ring slide, so that, for example, only every second pump piston delivery stroke leads to pressure build-up in the pump work space and thus to fuel injection. Accordingly, only half of the cylinders of the internal combustion engine are used to drive them. The purpose of this measure is to reduce fuel consumption in the partial load range.

It is also known from DE-OS 32 18 275 a fuel injection pump, in which instead of the radial bores provided in the above known fuel injection pump in the ring slide from the end face of the ring slide, diametrically extending grooves are provided, which now cooperate with only a single outlet opening of the relief channel. The ring slide is not only axially displaceable on the pump piston as a function of the adjustment of a fuel injection quantity regulator, but can also be rotated by a rotating device. By twisting it can be achieved that during the delivery stroke of the pump piston, the outlet opening alternates with each or every second delivery stroke of the pump piston with one of the diametrically extending grooves, depending on the number of grooves provided. For example, either the number of injections can be reduced to half, similarly to that known from the prior art mentioned above, or the pressure delivery of the fuel injection pump can be completely prevented. In addition, by reducing the width of the grooves, it is possible to achieve throttled outflow or "leakage" of fuel during the respective delivery stroke, which is intended to reduce the fuel injection rate in the low speed range. This means that the internal combustion engine can be operated, for example, in idle mode with reduced combustion noise.

In this known fuel injection pump, however, problems arise with regard to the control of the amount of fuel flowing out through the throttle cross sections. In particular, there are problems in continuously increasing the amount of fuel from the transition from the idling range to the partial load range, so that no load jump occurs when the load is taken up. In particular, the outflow of the amount of fuel in the known device depends on the speed, i.e. it decreases with increasing speed, since the throttling effect increases together with the reduced time cross section. Furthermore, problems arise if the fuel injection pump is assigned an injection start adjustment device which regularly consists in the first outlet opening being adjusted relative to the drive shaft rotational position of the fuel injection pump.

Advantages of the invention

The fuel injection pump according to the invention with the characterizing features of the main claim has the advantage that with a change in the stroke position of the ring slide at an idle or low partial load range of rotation of the ring slide, the stroke is changed, from which after the start of the pump piston, the second outlet opening in connection with the Tax opening comes. The fuel is delivered via this stroke without "leaking". In this way, when the load is taken up, the proportion of the delivery stroke of the pump piston which is conveyed through the second outlet opening without "leaking" can be continuously increased. This enables jerk-free load absorption in the idling range.

Advantageous further developments and improvements of the fuel injection pump specified in the main claim are possible through the measures listed in the subclaims. The embodiment of claim 2 ensures that the transition is simple between idle operation and part-load operation, a "leakage" of fuel can be switched off via the second outlet opening during the delivery stroke of the pump piston. Due to the design with the longitudinal channels, the free cross-section at the control point is continuously reduced, so that here, too, a jump-free transition behavior between idling and part-load operation is possible. The configurations according to claims 2 and 3 are advantageous alternative solutions for attaching the longitudinal channels in cooperation with the control opening. Advantageously, according to claim 7, there is a continuous automatic shutdown of the silent running device or the "leak" through the second outlet opening when the load is picked up or when the input of the desired torque is increased by an operator of the fuel injection pump according to the invention and for driving a motor vehicle provided internal combustion engine. The fuel injection pump is equipped with a conventional fuel injection quantity regulator working with a control spring.

In an advantageous development, a rotary magnet device is used for the adjustment of the ring slide, both in the stroke direction and in the direction of rotation, which is controlled by the electrical control device. In a particularly advantageous manner, the fuel injection quantity in the part-load to full-load range can be set precisely with a single control element, operation with the quiet-running device according to the invention can be made possible in the idling range or low partial-load range, and finally the silent-running device can be switched off when the load is taken up. This results in particular in accordance with claim 13 that in idle operation at the lowest load through the leakage process via the second outlet opening at the start of injection there is a low injection rate, which then occurs as soon as the control opening overlaps with one of the longitudinal channels comes into a higher funding rate. When the load is picked up, the proportion of the higher delivery rate is at the end of the delivery stroke, so that an injection characteristic is obtained in which the fuel is supplied to the injection points first with a low injection rate and then with a higher injection rate. This favors the combustion process and reduces noise. Due to this injection behavior, the upstream fuel injection quantity is reduced even further during the ignition delay.

drawing

Two embodiments of the invention are shown in the drawing and are explained in more detail in the following description. 1 shows a first exemplary embodiment with the aid of a fuel injection pump shown in longitudinal section, shown in simplified form, FIG. 2 shows a section through the pump piston of the exemplary embodiment according to FIG. 1 with a representation of the inventive design of pump piston and ring slide, FIG. 3 shows an equivalent embodiment to the exemplary embodiment according to FIG. 2, 4 shows the rotary drive of the ring slide on the basis of a section through the fuel injection pump perpendicular to the pump piston axis, FIG. 5 shows an angulation of the lateral surface of the pump piston in the area of its tax-effective part with associated control openings of the ring slide displaceable on this part according to FIG. 2, FIG. 6 shows the order of the injection The amount of fuel over the stroke of the pump piston at different load positions of the ring slide, FIG. 7 shows a second exemplary embodiment of the invention in modification of the exemplary embodiment according to FIG. 1 as a partial cross section ch a fuel injection pump, FIG. 8 is a representation of the ring slide movement or the position of the actuating member actuated in various operating ranges for shutdown exemplary embodiment according to FIG. 7, FIG. 9 shows an adjustment diagram of the adjusting element of the embodiment according to FIG. 7 and FIG. 10 in the diagram of the fuel quantity to be injected over the stroke of the pump piston at different degrees of shutdown of the quiet running device.

Description of the embodiments

A bushing 2 is arranged in a housing 1 of a fuel injection pump shown in FIG. 1, in the inner bore 3 of which a pump cylinder is formed, a pump piston 4 is driven by a cam drive 5 and executes a reciprocating and at the same time rotating movement. The pump piston encloses a pump working chamber 6 on its one end face and partially protrudes out of the inner bore 3 into a pump suction chamber 7 which forms a relief chamber and is enclosed in the housing 1.

The pump work chamber 6 is supplied with fuel via longitudinal grooves 8 arranged in the lateral surface of the pump piston and a suction bore 9, which passes radially through the bushing 2 and runs in the housing 1 and extends from the pump suction chamber 7, as long as the pump piston assumes its suction stroke or its bottom dead center position . The pump suction chamber is supplied with fuel via a feed pump 11 from a fuel tank, not shown here. A pressure control valve, not shown, controls the pressure in the suction chamber, depending on the speed, in order to e.g. to be able to carry out a speed-dependent spray adjustment hydraulically via a speed-dependent pressure. The start of stroke of the pump piston is adjusted to early with increasing speed in a known manner.

A longitudinal channel 14 leads from the pump working space 6 in the pump piston, which is designed as a blind bore and can be referred to as a relief channel is. From this, a transverse bore 15 branches off, which leads to first outlet openings 16 on the circumference of the pump piston 4, into an area in which it protrudes into the suction space 7. The outlet openings 16 are preferably diametrically opposite, which leads to a balanced hydraulic load on the pump piston. In this area, a quantity adjustment element in the form of a ring slide 18 is arranged on the pump piston, which can be rotated and displaced tightly on the pump piston and forms a first control edge 19 with its upper end face, through which the first outlet openings 16 are controlled.

A radial bore 20 branches off from the relief duct 14, which preferably runs coaxially with the pump piston axis, which leads to a distributor opening 21 on the circumference of the pump piston. In the working area of this distributor opening, feed lines 22 branch off in a radial plane from the inner bore 3 and are arranged distributed on the circumference of the inner bore 3 in accordance with the number of cylinders of the associated internal combustion engine to be supplied with fuel. The delivery lines each lead via a valve 23, which is designed as a check valve or as a pressure relief valve in a known manner, to the fuel injection points, not shown. To these, as soon as the suction bore 9 is closed by the jacket surface of the pump piston at the beginning of the delivery stroke of the pump piston after a corresponding rotation thereof, the fuel located in the pump work chamber 6 is conveyed via the relief channel 14, the radial bore 20 and the distributor groove 21. This conveyance is interrupted when the first outlet openings 16 are opened by the control edge 19 in the course of the pump piston stroke and come into connection with the suction chamber 7. From this point on, the remaining fuel displaced by the pump piston is only fed into the suction chamber. The higher the ring slide 18 is adjusted towards the pump work space, the greater the fuel injection quantity delivered by the pump piston.

The fuel injection quantity regulator 25 provided for adjusting the ring slide has a tensioning lever 26 which is designed to be pivotable about an axis 27 and has one arm and is coupled at its lever arm end to its regulating spring arrangement 28. This consists of an idle spring 29 which is arranged between the head of a coupling member 30 and the tensioning lever, the coupling member 30 being pushed through an opening in the tensioning lever and being connected to a main control spring 31 at the other end facing away from the head. This is in turn suspended from its other end on a swivel arm 33 which can be adjusted with an adjusting lever 35 via a shaft 34 which is passed through the pump housing. The adjusting lever can be operated arbitrarily by an operator between an adjustable full load stop 36 and an adjustable idle stop 37. E.g. the adjusting lever 35 is connected to the accelerator pedal which the driver of the motor vehicle with which the internal combustion engine and the injection pump are equipped, actuates in accordance with his torque request. Instead of the simple coil spring shown here as the main control spring, other control spring arrangements can of course also be used, which are designed in multiple stages and / or pretensioned.

A starter lever 39 can also be pivoted about the axis 27 and is designed with two arms and is coupled with one arm via a ball head 40 in a radial plane to the ring slide transverse groove 41 engaging with the ring slide. The other arm of the starter lever has a leaf spring 49 which, as a starter spring, is supported against the tensioning lever 26 in a spreading manner. Actuator 42 of a speed sensor acts in the form of a centrifugal force control arrangement 43 of a known type on precisely this lever arm of start lever 39. This is driven synchronously with the drive shaft 44 of the fuel injection pump via a gear transmission 45. With increasing speed, the actuator 42 together with the start lever 39 and the ring slide 18 moved against the force of the starting spring 42 until the starting lever on the tensioning lever 26 comes to rest. In the course of this movement, the ring slide is adjusted from a highest position closest to the pump workspace according to a start quantity setting to the pump piston drive side and the excess start quantity is thereby regulated. If the start lever comes into contact with the tensioning lever, both levers can be pivoted against the force of the idle spring 29 until the main regulating spring 31 then comes into effect on the idle area. Depending on the design of this spring as an all-speed governor spring or as an idle speed governor spring, the tensioning lever is moved further when the set speed is reached and the ring slide 18 is displaced to reduce the injection quantity. Depending on the position of the adjusting lever 35, a greater or lesser amount of fuel injection is injected at a certain speed.

For adjustment, the axis 27 is mounted on an adjusting lever 46 which can be pivoted about an axis 47 fixed to the housing and is held in contact with an adjustable stop 48 by a spring.

So far, the fuel injection pump corresponds to a known embodiment. In Figure 2, the development according to the invention is shown, which consists of the following: The long channel 14 in the pump piston or the relief channel 14 is extended according to Figure 2 beyond the exit of the transverse bore 15 to the pump piston drive side and there has a radial channel 50, in which one Throttle 51 is arranged. With the outlet opening of the radial channel 50, a second outlet opening 52 is defined on the circumference of the pump piston. Between this and the first outlet openings 16, which lie in a plane radial to the pump piston axis, longitudinal grooves 55 are arranged in isolation, which together form longitudinal channels with the partial surface of the inner bore 53 of the ring slide sliding on the jacket of the pump piston. The longitudinal grooves 55 can also be designed as longitudinal slots and at the same time also replace the throttle 51. An annular groove 54 is also arranged on the ring slide, which starts from the lateral surface of the inner bore. Finally, a channel 57 is provided between the control edge 19 of the ring slide and the annular groove 54 in the ring slide, which connects the inner bore 53 to the outer circumference of the ring slide in a radially extending manner. At the transition to the inner bore 53, the channel 57 is designed as a control opening 58 which, for example according to FIG. 5, can have the shape of an elongated hole extending in the axial direction. In the example shown, as can also be seen in FIG. 5, the outlet openings 16 initially have the circular cross section of the cross-bore exit surface and, attached thereto, a rectangular recess 60 with the boundary edge facing the control edge 19 and parallel to it. This training is used in a known manner for the rapid opening of relief cross sections. The longitudinal channels 55 are arranged so that they remain in connection with the annular groove 54 during the entire pump piston stroke. Likewise, the control opening 58 is arranged in such a way that the radial plane in which the control opening opens also remains in overlap with the ends of the longitudinal channels 55 facing away from the annular groove 54 over the entire pump piston stroke. Furthermore, the dimensioning of the axial distance h1 between the second outlet opening and the first outlet opening is such that it is smaller than the axial distance h2 between the first control edge 19 and the boundary edge 61 of the annular groove 54 on the pump drive side. The difference between these axial distances results in a usable leakage distance hl, which is also the difference of the possible useful stroke hn minus the preload stroke sx. These dimensions play a role in connection with the operation of the fuel injection pump in quiet operation, which will be explained in the following.

The ring slide also has, in its outer lateral surface, a longitudinal groove 62 extending in the axial direction with guide surfaces 63 pointing in the circumferential direction. A sliding part 65 engages in the longitudinal groove 62, which is gripped by the boundary surfaces or guide surfaces 63 of the longitudinal groove 62. The sliding part is pivotable in the circumferential direction to the ring slide 18 by an adjusting lever 66. According to FIG. 4, the adjusting lever is part of an angle lever 68 which can be pivoted about an axis 67, on the other lever arm 69 of which an adjusting finger 70 engages, which sits eccentrically on the end face 71 of a shaft 73 which is led outward through the housing from the pump suction chamber 7. At the outwardly projecting end of the shaft, an actuating lever 74 is rotatably mounted thereon and rotatable via a prestressed driving spring 75 in the form of a helical spring and a driving part 76 which is connected to the shaft 73 in a rotationally fixed manner. The driving part has an arm 72 to which the actuating lever 74 is held under the action of the driving spring 75 and is thus coupled to the shaft 73. The rotation takes place with the aid of a limit stop 77 connected to the shaft 73 only within a certain angular range, so that when the actuating lever 74 is actuated beyond this angular range, the latter only lifts from the arm 72 and is rotated further under tension of the driving spring, without the shaft 73 moving becomes.

By means of this rotating device described above, starting with the sliding part 65 up to the actuating lever 74, the ring slide 18 can be rotated without the first control edge 19 changing its stroke position, in particular in that the transverse groove 41 runs parallel to the first control edge 19. Likewise, when the ring slide 18 is adjusted by the ball head 40, the rotational position of the ring slide is not changed, since the groove 62 extends in the axial direction.

The fuel injection pump in its special design to achieve quiet running works as follows:

When the internal combustion engine is in idle mode after the starting process has been completed, the fuel quantity control is controlled by means of the idle spring 29. Basically, after each previous suction stroke, in which the pump work space is filled with fuel in a known manner, the pump piston carries out a stroke of size sv with the beginning of the delivery stroke until the second outlet opening 52 comes into connection with the annular groove 54. The first outlet openings are closed according to the dimensioning h1, h2 by the lateral surface of the inner bore 53 of the ring slide. During this stroke sv, the amount of fuel delivered by the pump piston is used to generate the injection pressure in the pump work space. This stroke is also called the relief stroke and takes up a relatively large part of the total stroke of the pump piston, as can be seen from FIG. 6. Injection could therefore take place from the stroke sv, since the distributor groove 21 is in connection with one of the pressure lines 22 and a pressure has been reached which corresponds to the opening pressure of the injection valve. However, if the second outlet opening is in connection with the annular groove 54, fuel can flow out to the suction chamber 7 via one of the longitudinal channels 55 and the control opening 58 via the channel 57. The outflow rate is determined by the throttle 51, which can also be formed by a reduced cross section at any point in the connection between the pump work space from the branching off of the radial bore 20 and the relief space. For reasons of a low harmful space, the position of the choke 51 described is advantageous. The outflow occurs only when the ring slide is in a rotational position which allows one of the longitudinal channels 55 to overlap with the control opening 58. The longitudinal channels 55 are corresponding to the number of he per revolution of the pump piston following delivery strokes distributed around its circumference, so that there is the possibility per pump piston delivery stroke to establish a connection between the annular groove 54 and suction chamber 7. Via this connection, fuel in the bypass for fuel delivery to the respective fuel injection nozzle leaks fuel into the suction space 7, so that the delivery rate to the injection nozzle is considerably reduced. The effective delivery stroke is determined by the position of the ring slide 18 and ends when the first outlet openings are opened via the first control edge 19. As a result of the relief, the pressure in the pump piston working chamber 6 drops below the opening pressure of the injection valves and the remaining fuel delivered flows back into the suction chamber 7 with the outlet surface of the outlet openings 16 always opening. FIG. 5 shows the development of the outer surface of part of the inner bore 53 of the ring slide for this method of operation, superimposed with the outer surface and the control openings of the pump piston contained therein in the region of the ring slide. A first position can be seen, in which the second outlet opening 52 just touches the lower boundary edge 61 of the ring slide 54. The associated longitudinal channel 55 is in full overlap with the annular groove and the control opening 58 is in overlap with the longitudinal channel or with the longitudinal groove 55 at its left end. The first outlet openings are fully closed by the circumferential surface of the ring slide and have the first control edge 19 not reached yet. In the second position, the pump piston is now raised further and has moved further in the direction of rotation, in the direction of the right-hand leaf edge in FIG. The second outlet opening 52ʹ in this position is in overlap with the annular groove 54, the longitudinal groove 55ʹ is still in overlap with the annular groove and with the control opening 58. The first outlet opening in position 16ʹ is still covered. A leakage current flows to the suction space 7, the injection rate is reduced by this leakage current. From the third position, however, 16ʺ is opened by the first control edge, although the longitudinal groove 55ʹ in connection with the control opening 58 and the second outlet opening 52ʺ are still connected with the annular groove 54. At this point the injection is stopped.

If the amount of fuel injected here is not sufficient to supply the internal combustion engine, the centrifugal force sensor 43 and the idle spring 29 are used to move the slide to the side of the pump work chamber, so that, with the same pump piston control, the second outlet opening 52 corresponds to the piston lift curve 79 shown in FIG. 5 later point in connection with the annular groove 54 comes. Fuel delivery takes a correspondingly longer time after a fuel preload stroke and then delivery to a reduced extent as shown in FIG. 6. The fuel injection quantity or rate is shown there over the stroke of the ring slide. The large rectangle on the left up to point sv is the quantity delivered by the pump piston that is necessary to pretension the fuel in the working area to the injection pressure. For the first case described above, this is followed by a stroke hl with reduced fuel injection rate up to the useful stroke hn, which at the same time corresponds to the stroke at full load VL. This is also the end of the stroke in idle mode with the low-noise device LV switched on. If, on the other hand, the ring slide is brought from this low load position into a higher load position, as just described, the stroke sx, at which the pump piston works at full delivery rate, increases from sv to line 2 or sxʹ. The funding with a reduced amount then extends to hnʹ. The difference between the two delivery rates results in a total amount of fuel injected. With further load absorption or with a further load on the internal combustion engine, the ring slide is moved further to the pump work space, so that only z. B. on line 5 or from which hub sxʺ can be leaked. Accordingly, the delivery stroke at hn dem, the pump piston delivery stroke for the starting additional quantity, is ended. It can be seen from this that it is possible in this way to take up a load with a full injection rate up to the height of the useful stroke hn. Depending on how this useful stroke hn is structurally adjusted, an operation in which fuel is leaking can increase the injection quantity up to quantities that correspond, for example, to the full-load injection quantity.

In FIG. 5, the piston elevation curve was reproduced at 79 at the injection time setting point 0 °. If, however, the spray start is shifted to earlier angles with increasing speed, up to 12 ° cam angle to the left in FIG. 5, one can imagine the opening cross sections 55, 52 and 16 shifted to the left with the control cross section 58 remaining. The shutdown device has the advantage, that it can be turned in the opposite direction to switch off than this early relocation of the control process. If one assumes that a leak duration of approx. 10 ° cam angle is required for a silent run, the turn-off rotation is reduced to this angle plus the necessary overlap in order to obtain a tight seal between the control opening and the longitudinal groove. The switch-off movement can therefore be kept very small, so that the entire device can also be used in a fuel injection pump which supplies more than four cylinders with each pump piston rotation.

In order to move from the operating position 58 shown in FIG. 5 to the switch-off position 58ʹ, the adjusting lever 74 is adjusted accordingly. This is coupled to the adjusting lever 35 and moved by it so that it brings the control opening 58 'into the switch-off position when the load is picked up or during the transition from idle mode to part-load mode. This results in an automatic shutdown device with load pick-up combined with a smooth transition of the fuel quantity metering without load jump.

To reduce the leakage distance, instead of the type of fuel quantity increase described above, the ring slide can also be rotated with the load pickup, in principle the same fuel quantity control results as is shown in FIG. 6 for the load pickup by lifting the ring slide.

An equivalent embodiment according to FIG. 3 is also possible for the embodiment of the invention shown in FIG. 2. Here, the longitudinal grooves 155 forming the longitudinal channels are laid in the lateral surface of the inner bore 53 of the ring slide. The annular groove 54 provided in the exemplary embodiment according to FIG. 2 then lies as an annular groove 154 at the end of the longitudinal grooves 155 on the pump work chamber side and is in constant connection with the radial channel 57. The remaining openings are arranged in the same manner as in the exemplary embodiment in FIG. 2. The control opening in this embodiment is used the second outlet opening 52 in cooperation with the longitudinal channels 155 analogous to the above-described method of operation between the longitudinal channels 55 and the control opening 58. Here, an angle of rotation adjustment of the ring slide, which also simultaneously takes over the switch-off function, comes into question for the load suspension or for controlling the relief quantity.

A second exemplary embodiment of the invention is shown in detail in FIG. Instead of the mechanical controller provided in FIG. 1 for adjusting the ring slide 18, a rotary magnet signaling mechanism known per se is now provided, of which only the actuating shaft 81 is shown here, which is guided fixed to the housing and at one end of which the magnetic signal mechanism (not shown) is seated and the other end of which an actuator in the form of an eccentric on the End face of the adjusting shaft 81 seated ball head 82 is arranged. This ball head engages in a recess 83 with a circular cross section on the circumference of the ring slide 18, the recess 83 being adapted to the shape of the ball head so that play-free actuation is possible. In a departure from the exemplary embodiment according to FIG. 1, this ball head 82 also replaces the sliding part 65 according to FIG. 2. A separate rotating device for the ring slide is therefore not provided. FIG. 8 shows a top view of the ring slide 18, with a start position St of the ball head 82 and a stop position Sp of the ball head. It can be seen here, as in FIG. 7, that the axis of the actuating shaft 81 lies next to the longitudinal axis of the pump piston.

The mode of operation of this embodiment is shown in FIG. The work area of the rotary magnetic interlocking is divided into two different work areas. The first work area I is located on the pitch circle of the movement circle of the ball head 82, which faces the pump work space. This area lies approximately symmetrically to an axis that runs parallel to the pump piston axis and intersects the axis of the actuating shaft 81. The ball head 82 essentially executes a movement in the circumferential direction of the ring slide along this pitch circle 85. The stroke movement of the ring slide is negligible. In this first working area, the ring slide is turned off. At the right end of the work area I, LV shows the silent run that has not been switched off, while in the left end area the silent run is switched off and at the same time the starting injection quantity is switched on. This position is marked with St. Below LV and St and in the center of the axis, assignments of the control cross section 58 to one of the longitudinal channels 55 are shown, specifically at the beginning of the stroke after passing through the preload stroke sv. The longitudinal channel 55 shown moves in the same sense as that shown in FIG. 5, that is to the right with simultaneous movement Stroke according to arrow c. In the LV position, in the starting position after passing through a stroke sv, in which the second outlet opening 52 comes into contact with the annular groove 54, the longitudinal channel 55 already overlaps at the left edge of the control opening 58. At the end of the conveying stroke, the longitudinal channel 55 is still in register, on the right side of the control opening 58. Following the switch-off movement, the longitudinal channel 55 in the central region overlaps with the right half of the control opening 58 after passing through the preload stroke sv. This overlap is maintained over a partial stroke, which becomes smaller the further the ring slide is turned towards position St in the switch-off direction. Finally, in position St, the longitudinal channel is no longer in overlap with the control opening 58 after passing through the preliminary stroke sv.

This embodiment has the advantage that during the preliminary stroke sv the fuel is biased with the maximum possible delivery rate analogously to FIG. 6, now shown in FIG. This is followed by a delivery stroke for position LV, seen over the stroke length h1, the leakage distance, in which the delivery rate is significantly reduced. This corresponds to the flatter lower rectangle along the abscissa in FIG. 11. If load is now taken up from the LV position, with increasing rotation to the left at the end of the conveying stroke, increasingly wide conveying sections arise, in which conveying is carried out at full conveying capacity after an initially reduced conveying rate. For example, the following applies to an adjustment position 2, which in principle corresponds to the adjustment position 2 of FIG. 6, which is conveyed with a reduced delivery rate after passing through the preliminary stroke section sv up to the stroke hnʹ and is conveyed again with full delivery rate from the stroke hnʹ to hn. This means that in the present case the injection process is adapted to the actual requirements of the internal combustion engine. During the start of spraying, the delivery rate is low, so that it does not become too large during the ignition delay time Store fuel quantities in the combustion chamber and the delivery rate is only increased towards the end of the delivery stroke.

The second working area II of the magnetic signal box comprises the normal operation of the internal combustion engine, in which without a quiet running device, i.e. is injected without fuel leakage or without a reduced fuel injection rate. Here, a partial circle 86 of the circular path of the spherical head 82 comes into effect, which laterally adjoins the first working area I after a certain intermediate area. This pitch circle 86 has a much larger directional component in the axial direction, so that when the ball head 82 rotates, a substantial stroke movement of the ring slide 18 can also be effected. At the left end of the second working area II, the ring slide has its highest position corresponding to the maximum injection quantity of the full-load injection quantity. This point is labeled VL. From the combination of control cross-section drawn above, it can be seen that the longitudinal channel 55 lies at the left of the control cross-section 58 at the beginning of the effective delivery stroke, i.e. after passing through the preliminary stroke section sv, and does not come into connection with this control cross-section even after passing through the total delivery stroke. With increasing rotation of the ring slide to the right starting from VL to low load ranges, the control opening 58 is further removed from the longitudinal channels, so that leakage in region II is completely eliminated. Along the partial circular path 86, by rotating the ball head 82, the ring slide reaches positions corresponding to low load until it is switched off. So here the controller regulates in the usual way.

The rotary magnetic interlocking, which is not shown here, is controlled by a corresponding control device, which is likewise not discussed or described here, wherein the ball head 82 is also used in rotational steps for work in work areas I and II can be put. With the help of the electronic control device, the ring slide can assume all possible and necessary positions. Continuous operation is possible in the main operating areas, idling with the silent running device switched on or with a reduced fuel injection rate, and also in the load area, working area II. On the other hand, when moving from one area to another, the magnetic interlocking must perform abrupt rotary movements.

In this embodiment, which is described in relation to FIGS. 7 to 10, only one bore is required on the ring slide for guiding the ball head 82. Instead of two grooves according to the embodiment of Figure 1. There is also no coupling of the adjusting lever to the adjusting lever. A corresponding electronic control is provided for this. Furthermore, no changes to the pump housing compared to a normal version are necessary and there are no additional forces on the accelerator pedal. Equally, however, a steady transition from quiet operation to partial load is possible without having to drive over the full load.

Compared to the known, the fuel injection pump according to the invention means an improvement in the function in the case of pump pistons that are less structurally loaded, which can be made much slimmer, in particular because of the elimination of a second relief channel according to the one prior art. In addition, there are no additional dead volumes in the high-pressure circuit, which would influence the accuracy of the spray quantity, particularly under the influence of the dynamics.

Claims (15)

1.Fuel injection pump for internal combustion engines with a pump piston (4) reciprocatingly and at the same time rotatingly driven in a pump cylinder (3) and thereby serving as a distributor of the delivered fuel, which delimits a pump working space (6) in the pump cylinder (3), by changing the fuel injection quantity delivered by the pump piston by controlling the opening of a first outlet opening (16) on the circumference of the pump piston of a relief channel (14) arranged in the pump piston (4) and leading from the pump working chamber (6) to a relief chamber (7) by means of a on the pump piston (4 ) by a fuel injection quantity regulator (25) within the relief chamber axially displaceable ring slide (18) which has a first control edge (19) which lies in a radial plane to the pump piston axis, via which the first outlet opening (16) can be controlled after a variable pressure stroke of the pump piston and with one from the relief channel (14 ) to a second outlet opening (52) on the circumference of the pump piston in the area of the coverability by the ring slide (18), which, to control the second outlet opening, has a channel (57) emerging on its inner lateral surface, which communicates with the relief chamber ( 7) is connected, characterized in that that on the inner lateral surface of the ring slide (18) an annular groove (54, 154) and between the pump piston circumference and the inner lateral surface of the ring slide limited longitudinal channels (55, 155) are provided, which are connected to the annular groove (54, 154) and from one the initial stroke (sx) of the pump piston (4) corresponding to the load-dependent axial position of the ring slide (18) can be connected to the second outlet opening (52) and one of the longitudinal channels (55) with the radial channel (50) with the by the duration of the overlap Channel (57) connecting control opening (58; 52) limited angle of rotation produce a connection containing a limiting throttle between pump piston working chamber (6) and relief chamber (7). 2. Fuel injection pump according to claim 1, characterized in that the ring slide (18) can be rotated by a rotating device (65, 68; 82, 81) and the duration of the connection of the control opening with the respective longitudinal groove (55) is adjustable. 3. Fuel injection pump according to claim 2, characterized in that the control opening, the outlet opening (58) of the channel (57) opening on the inner lateral surface of the ring slide (18) is that the longitudinal channels are longitudinal grooves (55) in the lateral surface of the pump piston and the second outlet opening (52) after the initial stroke (sx) comes into contact with the annular groove (54). 4. Fuel injection pump according to claim 2, characterized in that the control opening is the second outlet opening (52) on the pump piston and the longitudinal channels are arranged as longitudinal grooves (155) on the inner circumferential surface of the ring slide (18) and at the pump workspace end in the annular groove (154 ) open, which in turn is permanently connected to the channel (57). 5. Fuel injection pump characterized in that the axial distance (h2) between the pump piston drive-side boundary edge (61) of the annular groove (54) and the first control edge (19) by a leakage distance (h1) is greater than the axial distance (h1) between the second outlet opening (52) and first outlet opening (16). 6. Fuel injection pump according to claim 4, characterized in that the axial distance between the pump piston drive side boundary edge of the longitudinal channels (155) and the first control edge (19) by a leakage distance (hl) is greater than the axial distance between the second outlet opening (52) and the first outlet opening (16). 7. Fuel injection pump according to claim 4, characterized in that upon reaching the relief stroke (sx, sv) the control edge of the second outlet opening (52) depends on the angle of rotation with the respective longitudinal channel (155) and after a leak stroke (hl) the first outlet opening ( 16) reaches the first control edge (19). 8. Fuel injection pump according to one of claims 2 to 7, characterized in that the fuel injection quantity controller (25) has a speed sensor (43) which, contrary to the force of a control spring arrangement (42, 29, 28), the axial position of the ring slide (18) via a control lever (39) and has an adjusting lever (35), via which the load on the regulator lever (39) by the regulating spring arrangement can be changed arbitrarily and that the adjusting lever (35) is coupled to the rotating device (65) of the ring slide. 9. Fuel injection pump according to claim 8, characterized in that between the ring slide (18) and the control lever (39) a first coupling device permitting a rotational movement without changing the stroke of the first control edge is provided, consisting of a guide surface (41) lying radially to the pump piston axis and a sliding part (40) guided on these guide surfaces and that between the ring slide (18) and a swivel member (65, 66 ) the rotating device is provided with a second coupling device allowing a lifting movement without rotating the ring slide, consisting of guide surfaces (63) lying in the direction of the pump piston axis and pointing in the circumferential direction of the pump piston and a sliding part (65) guided on these guide surfaces. 10. A fuel injection pump according to claim 8 or 9, characterized in that the adjusting lever (35) has brought the ring slide into a rotational position at a position corresponding to the beginning of the partial load range when the load is received, in which the connection from the pump work chamber via the control opening to the relief chamber (7) is constantly above the entire pump piston delivery stroke is closed. 11. Fuel injection pump according to one of claims 2 to 7, characterized in that the rotation of the ring slide (18) is actuated at the same time with its adjustment by the fuel injection quantity regulator. 12. Fuel injection pump according to claim 11, characterized in that the fuel injection quantity regulator is a rotary magnet signal box with a shaft (81) at the end of which a spherical actuating member (82) is eccentrically seated, which engages in a recess (83) on the ring slide. 13. Fuel injection pump according to claim 12, characterized in that controlled by a control device by the rotary magnet device, the ring slide for a change in the duration of Overlap of the respective longitudinal channel (55) with the control opening is adjusted in a first working area (I), in which the actuating member (82) is moved on a partial circle extending substantially in the radial direction to the pump piston axis in a circumferential direction of the ring piston (18) and for changing the setting of the fuel injection quantity in the partial load range up to the full load range is adjusted in a second working range (II), in which the actuating element (82) moves on a partial circle which adjoins the pitch circle of the first working area and extends essentially in the axial direction of the pump piston is, the longitudinal channels (55) remain constantly separated from the control opening (58) within the second working area (II). 14. Fuel injection pump according to claim 13, characterized in that the control opening is assigned to the longitudinal channel (55) so that the shut-off movement of the ring slide (18) in the first working area (I) takes place counter to the direction of rotation of the pump piston and the regulating movement of the ring slide to reduce the the amount of fuel injected per pump piston stroke with its peripheral component takes place within the second working range (II) in the direction of rotation of the pump piston. 15. A fuel injection pump according to claim 14, characterized in that the change in the injection quantity in the first working area (I) results from a change in the distribution between the full delivery portion and the silent delivery portion, the full delivery portion building up from the injection end and in the second working area (II) Change to the end of funding (FE).

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