EP1084343A1

EP1084343A1 - Pumping device

Info

Publication number: EP1084343A1
Application number: EP99927875A
Authority: EP
Inventors: Wolfgang Dr. Heimberg
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-06-04
Filing date: 1999-06-04
Publication date: 2001-03-21
Also published as: AU4506799A; WO1999063217A1

Abstract

The invention relates to a pumping device comprising a pump assembly (4) which is configured as a reciprocating piston pump. The pump displaces fluid by means of a reciprocating piston (6, 7). The inventive pumping device also comprises a stop element (17, 18) which limits the delivery stroke of the reciprocating piston (6, 7) in the direction of delivery (13), and has a dosing device (5) which is driven electrically and independent of the pump assembly (4). Said dosing device is provided for determining the quantity of fluid to be injected by displacing the reciprocating piston (6, 7) with regard to the stop element (17, 18) around a determined, variable accumulating stroke which corresponds to the delivery stroke. Using the inventive pumping device, fluid can be precisely dosed during considerable throughput. The inventive pumping device can be used both during applications which required a high dosing precision as well as for a fuel injection device.

Description

Pump device

The invention relates to a pump device for conveying liquids.

The pump device according to the invention is intended e.g. be suitable for supplying liquids to chemoreactors. Chemical or biochemical reactions are carried out in chemoreactors. Two or more reactants can be brought together and / or exposed to certain physical conditions (temperature, pressure, etc.) so that a chemical or biochemical reaction takes place. For a successful reaction, it is a prerequisite that the reactants are fed to the chemoreactor in precisely metered amounts. Depending on the chemical reaction, it may also be necessary for the reaction partner (s) to be fed continuously at considerable throughputs.

Centrifugal pumps which convey a fluid by means of a continuously rotating impeller are usually used for such applications.

However, the chemical or biochemical reactions often require that the reactants supplied are metered very precisely, which cannot be achieved with such centrifugal pumps, which do offer the necessary throughput.

So-called perestal pumps are used for the precise supply of fluids. However, these perestal pumps are only suitable for pumping very small quantities.

Pump devices which are completely different in construction and application from centrifugal pumps and perestal pumps are injection devices for supplying fuel to a combustion chamber of an internal combustion engine. The requirements for a conventional injection device are completely different from the requirements for a perestal pump. A much higher pressure must be generated with injectors. Injection devices, if they are not operated with a separately controllable injection valve, have to build up or reduce the pressure at a point in time which is set to a few fractions of a second and they have to withstand much greater mechanical loads. Perestal pumps, on the other hand, can be dosed extremely precisely.

The invention has for its object to provide a pump device with which a fluid can be conveyed very precisely with considerable throughputs. Another object of the present invention is to provide a pump device which has both as an injection device for internal combustion engines and a meterability comparable to that of perestal pumps.

The objects are achieved by a pump device with the features of claim 1. Advantageous embodiments of the invention are specified in the subclaims.

The pump device according to the invention has a pump device and a metering device. The pump device is designed as a reciprocating piston pump. It has a stop element which limits the delivery stroke of the reciprocating piston in the delivery direction. The metering device is driven electrically and independently of the pump device.

The piston is displaced between two pumping processes by the metering device by a predetermined variable storage stroke in the opposite direction to the conveying direction, a predetermined amount of fluid being stored. The reciprocating piston is held in this retracted position until it is actuated in the conveying direction. The reciprocating piston displaces the amount of fluid previously sucked in. As a result, a precisely defined delivery stroke is carried out and the exact amount of fluid sucked or stored by the stroke of the lifting piston, e.g. fed to a reaction chamber of a chemoreactor.

Since the dosing device is driven electrically and independently of the pump device, it can set the amount of fluid to be conveyed exactly, since the corresponding electrical control signals can be applied to the dosing device by an electrical control device with any desired accuracy. The amount of fluid to be delivered is determined solely by the precisely definable stroke of the reciprocating piston, which is thus indirectly electrically controlled via the metering device.

With the pump device according to the invention, a long-term stable, exact metering of the fluid quantity is ensured with considerable throughputs in comparison to perestal pumps.

The pump device according to the invention is also suitable as an injection device for supplying fuel to the combustion chamber of an internal combustion engine. It can be used to build up the necessary pressure with the required time precision and it has the required mechanical strength for use on an internal combustion engine. In a preferred embodiment of the pump device according to the invention, a

Delay device is provided which delays the pressure build-up of the pump device. As a result, the pressure pulses have flanking rising and falling edges, as a result of which the entire pressure pulse widens at a lower maximum pressure. The pauses between the pressure pulses are correspondingly reduced, which is advantageous for the supply of fluids to chemoreactors, since the chemical or biochemical reactions taking place in the reactors can be interrupted or at least considerably inhibited if the pauses are too long, thereby reducing the efficiency of the Chemoreactor is affected. In the preferred embodiment, these pauses are significantly reduced with a delay device.

The pressures generated in fuel injectors are generally much greater than in chemoreactors. Such fuel injection devices have a non-positively driven piston which is freely movable in the conveying direction, as is the case with e.g. If electromagnetically driven fuel injection devices are the case, the delayed opening behavior of the injection valve leads to losses in energy transmission, i.e. the non-positively driven piston is braked considerably before the injection valve is fully opened.

18 shows the pressure profile of a conventional injection device having a reciprocating piston pump as the delivery element, which operates in particular according to the solid-state energy storage principle. The pressure at the injection nozzle suddenly rises to the maximum pressure P _max at a point in time ti. Due to pressure reflections at the injection nozzle, the injection pressure is not constant, but can fluctuate considerably. In particular, pressure troughs often occur (in FIG. 18 at t ₂ ), which lead to a significant deterioration in the injection behavior and in particular in the droplet quality. In these pressure valleys, the pressure can drop below the nozzle opening pressure of the injection nozzle, so that there can be brief interruptions in the injection process. This can lead to considerable impairments in the ignition and combustion behavior in the combustion chamber of the internal combustion engine. At the end of the injection pulse, the injection pressure gradually decreases due to the continuously slowing delivery piston, so that the initially good atomizing effect (at P _ma χ) decreases. These undefined pressure states at the end of the injection pulse are additionally superimposed by a bouncing of the nozzle needle, as a result of which both the droplet size and the amount of fuel become uncontrollable.

These disadvantages are avoided by the delay device and better energy transfer is achieved. The invention is described in more detail below using the drawings as an example. They show schematically:

Fig. 1 shows a first embodiment of the pump device according to the invention in

Cross section, Fig. 2 shows a second embodiment of the pump device according to the invention in

3, a diagram showing the pressure curve in a conventional reciprocating piston pump and the pressure curve in the pump device from FIG. 2,

Fig. 4 shows a third embodiment of the pump device according to the invention in

Cross section, Fig. 5 shows a fourth embodiment of the pump device according to the invention in

Cross-section, Fig. 6 shows a pump-nozzle system with a fifth embodiment of the pump device according to the invention in cross-section, Fig. 7 shows a pump-nozzle system with a sixth embodiment of the pump device according to the invention in cross-section, in which the metering device and the pump device in a line 8 shows a pump-nozzle system with a seventh exemplary embodiment of the pump device according to the invention in cross-section, in which the metering device and the pump device are arranged in a line, and a delay device is provided, FIG. 9 shows a pump-nozzle system with an eighth embodiment of the pump device according to the invention in cross-section, in which the metering device and the pump device are arranged in a line, FIG. 10 shows a pump-nozzle system with a ninth embodiment of the pump device according to the invention in cross-section, with a pneumatically operated pumping device 11, a pump-nozzle system with a tenth exemplary embodiment of the pump device according to the invention in cross-section, in which the metering device and the pump device are arranged in a line, the pump device being actuated pneumatically, FIG. 12 a diagram showing the pressure curve shows in a combustion chamber and in which the areas are marked to which gas under pressure is used

Actuation of a pneumatic injection device according to the invention can be deducted, 13a a dosing device with a very small clearance in cross section,

13b shows a valve disk used in the metering device shown in FIG. 13a,

14 shows an eleventh embodiment of a pump device according to the invention in cross section,

15 shows a twelfth exemplary embodiment of a pump device according to the invention in cross section,

16 shows a thirteenth exemplary embodiment of a pump device according to the invention in cross section,

17 shows a fourteenth exemplary embodiment of a pump device according to the invention in cross section,

18 shows a pressure curve at the injection nozzle when using a conventional injection device, and

19 shows a pressure curve at the injection nozzle when using a pump device according to the invention.

1 schematically shows a pump system with a first exemplary embodiment of a pump device 1 according to the invention.

The pump device 1 is connected to a connection part 3 via a pressure line 2. The connecting part 3 is arranged on a reaction chamber (not shown) of a chemoreactor for supplying a fluid.

The pump device 1 has a pump device 4 and a metering device 5. The pump device 4 is an electromagnetically operated reciprocating piston pump with a two-part reciprocating piston consisting of an actuating piston 6 and a storage piston 7.

The actuating piston 6 is an armature of an electromagnet 8 and is mounted in a cylindrical armature space 9 which is delimited by a first tube section 10 of a housing body 11. On the outside, the tubular electromagnet 8 is seated on the first tube section 10.

The pipe section 10 and the electromagnet 8 are encompassed by a pump housing 12, which also closes the rear end of the pipe section 10 in the conveying direction 13 with a cover section 14. On the inside of the cover section 14 there is a stop element 15, for example made of an elastomer material, thermosetting material or brass, for the actuating piston 8. The actuating piston 6 is formed from a cylindrical body which bears on the inner surface of the first tube section 10. Longitudinal grooves can be introduced on the lateral surface of the actuating piston 6, so that when the actuating piston 6 moves in the conveying direction 13 or counter to the conveying direction 13, a fluid located in the armature space can flow past the actuating piston 6 and does not inhibit its movement. However, the armature space 9 is preferably sealed off from the areas carrying fluid and free of fluid. In such an embodiment, no longitudinal grooves are to be provided on the anchor body.

At the front end of the armature chamber 9 in the direction of conveyance 13, the housing body 11 forms a passage, which is thinner than the inner diameter of the armature chamber 9 and is delimited by an annular web 16, in which a stop bush 17 is inserted. The stop bush 17 protrudes from the ring web 16 into the armature space 9 and forms a stop edge 18 with its end edge pointing opposite to the conveying direction 13.

The storage piston 7 is displaceably mounted in the stop bush 17. The storage piston 7 has, at its end pointing opposite to the conveying direction 13, a stop disk 19 which overlaps the stop edge 18 of the stop bush 17.

The diameter of the stop disk 19 is smaller than the inner diameter of the armature space 9.

A spring 20 is arranged between the actuating piston 6 and the stop element 15 rearward in the conveying direction 13. The spring 20 acts on the actuating piston 6 together with the storage piston 7 in the conveying direction 13, that is to say in the direction of the pressure chamber 21.

The actuating piston 6 and the accumulator piston 7 are moved together in the first pipe section 10. Therefore, they can also be made in one piece.

A pressure chamber 21 arranged upstream of the pump device 4 in the conveying direction 13 is formed in the housing body 11. The pressure chamber 21 has a connection opening 22 for connecting the pressure line 2 leading to the connection part 3 and also an opening 23 leading to the metering device 5. In the connection opening 22, a standing pressure valve 24 is used, which only opens the connection opening from a certain passage pressure within the pressure chamber 21. In the opening leading to the metering device 5 there is an overflow valve 25 which is a check valve opening in the direction of the pressure chamber 21. The pressure chamber 21 extends into the inner region of the stop bushing 17, so that it relates to the pump device 4 is limited by the inner wall of the stop sleeve 17 and the front end face of the accumulator piston 7 in the conveying direction 13.

The metering device 5 is formed on the same housing body 11 as the pump device 4 and has a second tube section 26 which extends transversely to the conveying direction 13 of the pump device 4, namely in the pumping direction 27. A metering piston 28, which consists of a tubular armature body 29 and a guide pin 30 projecting on its two end faces, is displaceably mounted in the second tube section 26. The guide pin 30 is supported with its two ends in a guide bushing 31, 32 inserted in a fixed manner in the second tube section.

An inwardly projecting annular web 33 is formed on the area of the metering device 5 which is at the front in the pumping direction. A metering spring 34 is inserted between the ring web 33 and the front end face of the armature body 29 and presses the metering piston 28 in the direction of the rear guide bush 32.

On the outside of the second pipe section 26, an electromagnet 35 is arranged around the second pipe section 26 to actuate the metering piston 28. The electromagnet 35 and the second tube section 26 are surrounded by a metering device housing 36, which also closes the rear end of the metering device 5 in the pumping direction 27 with a cover section 37.

In the area between the overflow valve 25 and the stroke area of the metering piston 28, a fluid supply line 38 opens into the second pipe section 26. At the opening area of the fluid supply line 38 to the second pipe section 26, a check valve 39 is arranged, which prevents backflow into the fluid supply line 38.

In this exemplary embodiment, the first pipe section 10 and the second pipe section 26 of the housing body 11 are arranged at right angles to one another. This arrangement is compact and therefore convenient, but it is not necessary. The two pipe sections can be arranged at any other angle to one another; e.g. it is also possible that the pump device 4 and the metering device 5 are arranged diametrically opposite to the pressure chamber 21.

In the embodiment shown in FIG. 1, only one metering device 5 is provided. However, two or more metering devices can also be provided, each opening to the pressure chamber 21. The dosing devices are, for example, star-shaped in one to the drawing plane of Fig. 1 perpendicular to the pressure chamber 21 is arranged.

The mode of operation of the first exemplary embodiment of the pump device according to the invention is explained below.

In the state of the pump device shown in FIG. 1, the accumulator piston 7 rests on the abutment edge 18 of the stop bush 17 due to the pressure exerted by the spring 20 on the unit consisting of the actuating piston 6 and the accumulator piston 7 with its washer 19. that is, the storage piston 7 is fully inserted into the stop bush 16.

At the same time, the metering piston 28 is in its initial state in which it is pressed by the metering spring 34 away from the pressure chamber 21 against the rear guide bush 32. The pump device assumes this initial state after a completed pumping process.

To prepare for a pumping process, one or more metering processes are carried out, in which the metering piston 28 of the metering device 5 is actuated by the electromagnet 35, so that it in each case conveys fluid into the pressure chamber 21. The delivery pressure is lower than the passage pressure of the auxiliary pressure valve 24, so that the fluid cannot flow into the pressure line 2 leading to the injection valve 3.

The fluid fed into the pressure chamber 21 pushes the accumulator piston 7 by an exactly definable, variable accumulator stroke into the armature space 9 of the pump device 4 against the action of the accumulator piston spring 20. The overflow valve 25 prevents the fluid from flowing back into the metering device 5 21 located fluid and the storage piston spring 20 acting on the delivery piston 7 is held in position after the dosing process of the delivery piston 7, so that a predetermined amount of fluid is stored in the pressure chamber 21.

The storage stroke can be carried out by one or more metering processes, that is to say that the metering piston 28 carries out one or more delivery strokes in order to convey the fluid for displacing the storage piston 7 into the pressure chamber 21. If a storage stroke is carried out with several dosing processes, a small dosing device 5 can be used in order to generate a nevertheless considerable storage stroke. This allows miniaturization of the entire pump device. After the metering process, the magnet 35 of the metering device 5 is switched off and the metering piston 28 is pressed into its initial state by the metering spring 34, as a result of which fluid is sucked out of the fluid supply line 38.

To pump the fluid stored in the pressure chamber 21, the actuating piston 6 is moved in the conveying direction 13 by the electromagnet 8 of the pump device. Here, the actuating piston 6 actuates the accumulator piston 7 and moves it in the conveying direction 13.

The storage piston 7 displaces the fluid located in the stop bush 17 in the region of its delivery stroke when it moves in the delivery direction 13.

The fluid is thus fed through the standing pressure valve 24, the pressure line 2 and the connecting part 3 to the reaction chamber of a chemoreactor.

Since the delivery stroke of the storage piston 7 corresponds to the storage stroke, which is precisely preset by means of the metering device 5, the amount of fluid to be displaced by the delivery piston 7 or the amount of fluid supplied to the reaction chamber is precisely defined.

In the pump device according to the invention, the amount of fluid to be injected is thus determined by the storage stroke that can be adjusted by means of the metering device. The accumulator stroke of the accumulator piston 7 is not subject to any signs of aging, so that long-term stable metering of the pump quantity is ensured.

2 shows a second exemplary embodiment of the pump device according to the invention. It has essentially the same structure as the first embodiment, which is why the same parts are denoted by the same reference numerals and a detailed description can be omitted.

The second exemplary embodiment differs from the first exemplary embodiment in that the actuating piston 6 is designed as a hollow body with a cylindrical jacket wall 6a, a bottom wall 6b rearward in the conveying direction 13 and an annular web 6c projecting inward at the front end region in the conveying direction 13.

The hollow actuating piston 6 thus delimits a displacement space 40. The storage piston 7 engages in the displacement space 40, the storage piston 7 consisting of an elongated, cylindrical base body 7a and a disk-shaped, radially outwardly projecting guide part 7b in the conveying direction 13. The guide part 7b engages behind the inwardly projecting projection 6c of the actuating piston 6, the guide part abutting the inner surface of the jacket wall 6a. The storage piston 7 is thus slidably mounted in the actuating piston 6 with its guide part 7b.

A coupling spring 41 is inserted between the guide part 7b of the accumulator piston 7 and the bottom wall 6b of the actuating piston 6. The actuating piston 6 and the accumulator piston 7 thus form a spring-coupled system.

This spring-coupled system forms a delay device, the function of which is explained below.

The jacket wall 6a of the actuating piston 6 has a longitudinal slot extending in the axial direction, so that fluid penetrating into the displacement space 40 can flow in or against the conveying direction 13 and neither the relative movement between the actuating piston 6 and the metering piston 9, nor the displacement movement of the actuating piston 6 hindered in the pumping device 4.

The mode of operation of the second exemplary embodiment is explained below.

The mode of operation of the second exemplary embodiment essentially corresponds to that of the first exemplary embodiment, the pressure build-up being delayed due to the special design of the reciprocating piston as a spring-coupled system.

In reciprocating piston pumps without such a spring-coupled system, the medium is conveyed with short-term pressure pulses (I in FIG. 3), especially if it is an incompressible liquid. Such a pressure pulse has very steeply rising and falling edges. Such sudden pressure changes, which are carried out at high frequency, produce a loud noise and vibrations which can negatively affect the entire device. These extremely steep flanks also cause superimposed vibrations that can lead to malfunctions. The relatively long pauses occurring between two pressure pulses I can lead to an interruption of the chemical or biochemical reaction in a chemoreactor. This means that the reaction would have to be restarted with each pressure pulse or would not proceed in the desired manner. Characterized in that the accumulator piston 7 is coupled to the actuating piston 6 by means of the coupling spring 41, a pressure pulse II (FIG. 3) with flatter rising and falling flanks is generated.

Since the accumulator piston 7 is pushed with its guide part 7b into the displacement space 40 against the spring action of the coupling spring 41 when the pressure builds up, the pressure build-up of the pressure pulse II is delayed. As a result of this delay in the build-up of pressure, the maximum pressure reached is lower, but the pressure pulse II lasts considerably longer.

This time extension of the pressure pulse II is achieved by buffering the energy introduced into the actuating piston 6 by means of the electromagnet 8 in the coupling spring 41, which energy is delivered to the accumulator piston 7 after the actuation stroke of the actuating piston 6 has been completed.

As a result, the duration of an individual pressure pulse II can be extended, the frequency and the duration of the current pulses fed into the electromagnet 8 remaining unchanged. In the second embodiment, the pressure / pause ratio over time is considerably higher than in the case of a reciprocating piston pump which does not have a spring-coupled reciprocating piston. This is particularly advantageous if the chemical reactions taking place in the chemoreactor are sensitive to strong pressure fluctuations and pressure pauses.

The coupling spring 41 is inserted with a prestress, the spring hardness and the prestress being set such that the storage piston 7 does not strike the bottom wall 6b. This means that the spring force generated by the coupling spring 41 in the compressed state is greater than the counterforce exerted on the accumulator piston 7 by the maximum pressure of the pressure pulses II.

The pump device according to the second embodiment thus combines the advantages of high metering accuracy with those of low pulsation. It is therefore particularly well suited for the supply of media to chemoreactors.

In this embodiment too, a plurality of metering devices 5 can be connected to a common pressure chamber 21. If the metering devices 5 are operated in the same cycle, the fluids supplied by the individual metering devices 5 are mixed directly in the pressure chamber 21 and fed to the chemoreactor. The pump device according to the invention thus takes on a mixing function, the fluids being mixed and immediately be fed to the chemoreactor after mixing. This is ideal for fast-paced

Reactions because the fluids can mix and react in the chemoreactor. With the mixing pump device according to the invention, several reactive fluids can be fed to a chemoreactor via only a single connection.

The metering devices 5 can also be operated alternately, with a single metering device in each case supplying a specific fluid to the pump device during a work cycle, which pump device conveys the fluid to the chemoreactor. Another fluid is supplied from another metering device during the next work cycle. In this method, the fluids are fed to the chemoreactor in succession, alternately by a pump device. The complete mixing then takes place only in the reaction chamber of the chemoreactor.

The quantity ratio of the fluids to be mixed can be adjusted by the frequency and the stroke with which the metering piston 28 is actuated. The cross section of the metering devices can be selected according to the expected fluid quantities. To achieve high fluid throughputs, several metering devices 5 can be provided, which may also convey the same fluid.

Fig. 4 shows a third embodiment of a pump device according to the invention, which corresponds essentially to the first embodiment. The same parts are therefore provided with the same reference numerals.

A passage 43 leading to a delay chamber 42 opens onto the pressure chamber 21. The delay chamber 42 is designed like a blind hole with a jacket wall 44 and a bottom wall 45 and has a hollow cylindrical shape. In it a delay piston 46 is slidably mounted, which is flush with the jacket wall 44 of the delay chamber 42. On the side of the delay piston 46 facing away from the pressure chamber 21, a recess for receiving a compression spring 47 is made in the bottom wall 45, which is inserted with a prestress between the delay piston 46 and the recess made in the bottom wall 45.

The operation of this third embodiment is explained below.

When the electromagnet 8 is switched on, the actuating piston 6 and the metering piston 7 are moved by the magnet 8 in the conveying direction 13, as a result of which the fluid is displaced from the pressure chamber 21 to the connecting part 3. If a by the bias of the compression spring 47 in the Delay chamber 42 reaches the set deceleration pressure P in the pressure chamber 21, the fluid escapes into the delay chamber 42, the delay piston 46 being pushed into the delay chamber 42. As a result, the pressure build-up in the

Pressure chamber 21 and consequently delayed in the pressure line 2, so that the pressure does not increase abruptly, but rather increases gradually.

The spring hardness of the spring 47 and the maximum stroke (= distance between the delay piston 46 and the bottom wall 45 in the initial state) of the delay piston 46 are selected so that the delay piston 46 does not strike the bottom wall 45. As a result, the pressure peaks are “cushioned”, as in the second exemplary embodiment.

The pretensioning force is preferably set as low as possible so that the deceleration of the pressure rise begins as early as possible. The spring hardness is expediently chosen such that after the delay piston 46 has been completely lifted in the delay chamber 42, the force exerted by the compression spring 47 is slightly greater than the pressure force exerted on the delay piston 46 by the maximum pressure of the pressure pulses II.

A fourth exemplary embodiment of the invention is shown in FIG. 5, which has two metering devices 5, 5 ^' and a pump device 4. The metering devices 5, 5 ^' are identical to those in the first and second exemplary embodiments, which is why a new description can be omitted.

The pump device 4 is a double-acting pump device with an actuating piston 6 and two storage pistons 17, 17 ^' . The actuating piston 6 is slidably supported in a cylindrical armature space 9, which is delimited by a first tube section 10 of a housing body 11. On the outside of the first tube section 10 there are two electromagnets 8, 8 ^' . The two electromagnets 8, 8 ^' are arranged symmetrically about a plane of symmetry 48, which is arranged perpendicular to the longitudinal direction of the first pipe section 10 and intersects it at its longitudinal center. The electromagnets 8, 8 ^' are in turn surrounded by a pump housing 12. Adjacent to the electromagnets 8, 8 ^' , magnetic air gaps are formed in the first tube section 10, ie the tube section 10 has annular interruptions in which ring elements 49 made of magnetic non-conductive material are arranged.

At the two ends of the armature space 9 that are distant from the plane of symmetry 48, the housing body 11 forms one that is thinner than the inner diameter of the armature space 9 an annular web 16 or 16 ^' limited passage, in each of which a stop bush 17,

17 ^'is used. The stop bushings 17, 17 ^'project from the annular rib 16, ^16' in the armature space 9, and form with their counter to the conveying direction 13 and 13 ^'facing end edge a stop edge 18 or ^18'.

The storage pistons 7, 7 ^' are each slidably supported in the stop bushings 17, 17 ^' . The storage pistons 7, 7 ^' each have, at their ends pointing opposite to the conveying directions 13 and 13 ^', a stop disc 19, 19 ^'which overlaps the stop edges 18, 18 ^{' of} the stop bushes 17, 17 ^' .

The actuating piston 6 is a cylindrical body, which lies with its outer surface against the inner wall of the first tube section. The actuating piston 6 preferably has longitudinal grooves on its lateral surface, which a fluid filling the armature space 9 can flow past.

Centering springs 50, 50 ^' are inserted between the end faces of the actuating piston 6 and the ring webs 16, 16 ^' . The centering springs 50, 50 ^' are of identical design, that is to say that they have the same length and spring hardness. The centering springs 50, 50 ^' hold the actuating piston 6 symmetrically about the longitudinal center of the first tube section 10 or symmetrically about the plane of symmetry 48.

The mode of operation of the fourth exemplary embodiment is explained below.

The metering devices 5, 5 ^' convey fluids, as in the exemplary embodiments described above, into the pressure chambers 21, 21 ^' so that the storage pistons 7, 7 ^' carry out a corresponding storage stroke.

If e.g. B. the magnet 8 is energized, the actuating piston 6, which is an anchor to the two magnets 8, 8 ^' , is pulled into the magnet 8 in the first conveying direction 13. The actuating piston 6 strikes the first accumulator piston 7 so that it executes a delivery stroke and displaces the fluid from the first pressure chamber 21.

The first centering spring 50, compressed during the delivery stroke, moves the actuating piston 6 back into its starting position after the current switching of the magnet 8 has ended. Preferably, the second magnet 8 'is energized simultaneously with this return movement of the actuating piston 6, so that the actuating piston 6 strikes the second accumulator piston 7' and displaces it in the second conveying direction 13 '. pushes. After the current switching of the second magnet 8 'and the second delivery stroke has ended, the actuating piston 6 is moved back into its starting position by the second centering spring 50'. A further delivery stroke on the first accumulator piston 7 can follow this return movement.

This pump device is preferably operated such that is supplied during the delivery stroke of one of the two accumulator piston 7, 7 ^'at the opposite accumulator piston 7, ^7' of the corresponding metering fluid. Because one of the accumulator pistons is “loaded” while the other accumulator piston is carrying out a delivery stroke, the actuating piston 6 can be moved back and forth between the two accumulator pistons without interruption and execute a large number of conveying pulses in rapid succession.

With this pump device, two highly reactive fluids can be fed to a chemoreactor, whereby they are only mixed in the chemoreactor. The provision of the double-acting pump device creates an inexpensive, simple structure which, when operated at the resonance frequency of the oscillating actuating piston 6, requires little electrical power to convey the fluids.

In the exemplary embodiment shown in FIG. 5, it is fundamentally possible for the storage pistons 7, 7 'to move out of their respective stop bushes 17, 17' in the idle state, for example due to gravity. This is practically irrelevant for operation with a specific delivery frequency of 50 Hz, for example, since the accumulator pistons 7, 7 'are pushed into the stop bushes 17, 17' during the first reciprocating movement of the actuating piston 6, and this into the pressure chamber 21 , 21 'introduced fluid prevents a renewed, uncontrolled moving out of the storage pistons 7, 7' from the stop bushings 17, 17 '.

For operation with longer pauses in delivery, it may be expedient to provide the centering springs 50, 50 'between the actuating piston 6 and the storage pistons 7, 7', so that the storage pistons 7, 7 'are pushed into the stop bushes 17, 17' by the centering springs would.

A centering of the actuating piston 6 in the first pipe section 10 is expedient, but is not necessary if the pump device is to be operated with continuously oscillating actuating pistons, since the actuating piston 6 then does not remain in the central starting position defined by the centering springs. If the magnets 8, 8 ^'are sufficiently dimensioned, the actuating piston 6 can also be springs from one position against a storage piston towards the other

Storage pistons are moved. The centering springs can also be omitted here.

The pump device according to the invention is described above with reference to a pump system in which the fluid is supplied to the reaction chamber by means of a connecting part. This connector can e.g. a pressure valve or any other connection element to introduce the fluid into the reaction chamber.

The exemplary embodiments described above are intended for supplying one or more fluids to a chemoreactor. Of course, the pump device according to the invention can also be used to supply fluid to other devices. The pump devices can thus be used to supply fuel to a combustion chamber of an internal combustion engine. In a fuel injection device, the connection part 3 is an injection nozzle 3 which is arranged directly adjacent to the combustion chamber.

In the following, further exemplary embodiments of pump devices according to the invention are described which are designed as injection devices for internal combustion engines. They can also be used to supply liquids to chemoreactors.

6 schematically shows an injection device according to a fifth exemplary embodiment of a pump device 1 according to the invention. This injection device is a pump-nozzle system with a pump device according to the invention, the pressure line of which is connected to an injection nozzle 3.

This fifth embodiment corresponds essentially to the first embodiment. The same parts are labeled with the same reference numerals.

The actuating piston 6 shown in FIG. 6 is formed in two parts from an armature body 52 and a guide tube or guide pin 55. It can also be formed in one piece and it is also possible to provide an anchor that is only guided through the pipe section 10 without a guide pin.

Longitudinal grooves are made in the lateral surface of the armature body 52 and the guide pin 55 is hollow, for example, if the armature space is flooded with fuel, so that when the actuating piston 6 moves in the conveying direction 13 or counter to the conveying direction 13, a fuel located in the armature space on the actuating piston 6 can flow past and its movement not inhibit. However, the armature space 9 is preferably sealed off from the areas carrying fuel and is free of fuel. In such an embodiment, no longitudinal grooves are to be provided on the anchor body.

An armature spring 50 is inserted between the annular web 16 of the housing body 11 and the end face of the actuating piston 6 pointing in the conveying direction 13. A storage piston spring 51 is inserted between the stop disk 19 and the end face of the actuating piston 6 pointing in the conveying direction 13. On this end face, a recess 53 is made, in which the storage piston spring 51 sits and in which the storage piston spring 51 is received when the same is compressed. The storage piston spring 51 is surrounded by an annular web 54 on the stop disk 19.

The provision of a metering device 5 and a pump device 4 in accordance with the invention decouples the metering of the fuel quantity from the generation of the fuel injection pressure.

Since the accumulator piston 7 protrudes further into the armature space 9 after a dosing process with a larger quantity of fuel to be injected than with a smaller quantity of fuel to be injected, the acceleration path of the actuating piston 6 is smaller with larger quantities of fuel to be injected than with smaller quantities of fuel. With smaller amounts of fuel, the length of the acceleration path is greater than with large amounts of fuel, as a result of which the kinetic energy stored by the actuating piston is greater than with large amounts of fuel. As a result, smaller amounts of fuel are injected with higher pressure than larger amounts of fuel. As a result, small amounts of fuel are atomized very finely and braked in the combustion chamber directly in the area behind the nozzle. Larger amounts of fuel injected at lower pressure, on the other hand, form larger drops that penetrate further into the combustion chamber. This effect is very advantageous for the ignition behavior of the internal combustion engine, since the smaller amounts of fuel in the vicinity of the injector 3 are braked and can be ignited exactly by arranging the spark plug accordingly, whereas larger amounts of fuel are evenly distributed in the combustion chamber and accordingly burn well. This ideal distribution of the fuel for the combustion process, in which smaller amounts of fuel are enriched in the area of the spark plug and larger amounts of fuel are more evenly distributed in the combustion chamber, is called charge stratification.

A sixth exemplary embodiment of the fuel injection device according to the invention is shown in FIG. 7. In this fuel injection device, the pump device 4 and the metering device 5 are arranged along a line. This fuel injection device has an essentially tubular housing body 1 1, which consists of a first pipe section 10 and a second pipe section 26, which are arranged coaxially with one another, a transverse plate 57 being formed between the first and the second pipe sections 11, 26. The pump device 4 is formed in the area of the first pipe section 10 and in the area of the second pipe section 26 the metering device 5 is formed adjacent to the transverse plate 57 and subsequently the pressure chamber 21 in the conveying direction 13.

The pump device 4 has an actuating piston 6 which is mounted in an armature space 9 and which consists of a tubular armature body 52 and an armature pin 55 which penetrates the armature body 52 in the longitudinal direction and which projects on both end faces of the armature body 52. The armature space 9 is delimited by the first tube section 10 of the housing body 11. An electromagnet 8 sits on the lateral surface of the first pipe section 10. The pipe section 11 and the electromagnet 8 are encompassed by a pump housing 12, which also closes the rear end of the pipe section 10 in the conveying direction 13 with a cover section 14.

Arranged at the front end of the pipe section 10 in the conveying direction 13 is the transverse plate 57 which is formed in one piece with the first pipe section 10 and in the middle of which a passage is made. A guide bushing 56 is seated in this passage. At the rear end of the armature space 9 there is a further guide bushing or stop bushing 15. The armature pin 55 of the actuating piston 6 is displaceably mounted in the two guide bushings 15, 56. An armature spring 50 is inserted between the end face of the armature body 52 pointing forward in the conveying direction 13 and the transverse plate 57, which acts on the actuating piston 6 with a force counter to the conveying direction 13.

The metering device 5 arranged on the second pipe section 26 has a metering piston 28, which consists of a tubular armature body 29 and a guide pin 30 projecting on its two end faces. The guide pin 30 is supported with its two ends in the guide bushing 56 inserted in the cross plate or in a stop bushing 17. The stop bushing 17 is inserted in a passage which is delimited by an annular web 16 projecting inwards on the second tube section 26. Between the armature body 29 of the metering piston 28 and that inserted in the cross plate 57

A bushing 56 is inserted into the guide bushing 56, which acts on the metering piston 28 with a force in the conveying direction 13 and presses it against the stop bushing 17.

In the area of the metering device 5, a further magnet 35 for actuating the metering piston 28 is arranged on the outside on the second pipe section 26, which is enclosed by a cylindrical metering device housing 36.

The pressure chamber 21 arranged upstream of the metering device 5 in the conveying direction 13 is laterally delimited by the second pipe section 26. This pipe section 26 delimiting the pressure chamber 21 is provided in the conveying direction 13 at the front with a connection opening 22 for connecting the high-pressure line 2 leading to the injection nozzle 3. A standing pressure valve 24 is used in the connection opening, which only opens from a certain passage pressure within the pressure chamber 21 and releases the connection to the injection valve 3.

In the area of the stop bushing 17, a fuel supply 58 opens into the pressure chamber 21 between the auxiliary pressure valve 24 and the metering piston 28. A check valve 39 is arranged in the fuel supply 58, which prevents a backflow into a fuel supply line 38 connected to the fuel supply 58.

The operation of this sixth embodiment of the invention is similar to that of the fifth embodiment and is explained below.

During the metering process, the magnet 35 of the metering device 5 is energized so that the metering piston 28 executes a storage stroke counter to the conveying direction 13 and sucks fuel out of the fuel supply line 38. The fuel in the area of the stop bushing 17 cannot escape due to the stationary pressure valve 24 and the check valve 38 and blocks a return movement of the metering piston 28. At the end of the metering process, the magnet 35 is de-energized, the metering piston 28 remaining in the position of the storage stroke , since on the one hand its return movement is blocked and on the other hand the metering spring 34 acts on the metering piston 28 in the conveying direction 13. Here, the metering piston 28 acts as a storage piston, since it stores a predetermined amount of fuel in the pressure chamber 21.

During the injection process, the magnet 8 of the pump device 4 is energized so that the actuating piston 6 is moved in the conveying direction, wherein it stores kinetic energy during an acceleration phase. At the end of the acceleration phase, the operator Cleaning piston 6 on the metering piston 28 and transfers its kinetic energy to this. The metering piston 28 is pressed into the stop bushing 17 until it strikes the front end face of the armature body 29 on the stop edge 18 of the stop bushing 17 and is stopped. The delivery stroke thus corresponds to the storage stroke and the amount of fuel displaced by the metering piston 28 corresponds to the amount of fuel drawn in and stored during the metering process. Since the amount of fuel displaced by the metering piston is conveyed into the high-pressure line 2 and is injected into the combustion chamber by means of the injector 3, the amount of fuel injected is measured precisely by the metering process and is independent of parameters which change over time, such as the opening pressure and flow resistance of the injector .

8 shows a seventh exemplary embodiment of the fuel injection device according to the invention. It has essentially the same structure as the sixth embodiment, which is why the same parts are given the same reference numerals and a detailed description can be omitted.

In this exemplary embodiment, a passage 43 leading to a delay chamber 42 opens out at the pressure chamber 21. The delay chamber 42 is designed like a blind hole with a jacket wall 44 and a bottom wall 45 and has a hollow cylindrical shape. In it a delay piston 46 is slidably mounted, which is flush with the jacket wall 44 of the delay chamber 42. On the side of the delay piston 46 facing away from the pressure chamber 21, a recess for receiving a compression spring 47 is made in the bottom wall 45, which is inserted with prestress between the delay piston 46 and the recess made in the bottom wall 45.

The operation of this seventh exemplary embodiment corresponds to that of the sixth exemplary embodiment in the metering process, the pressure build-up being delayed in the injection process as in the second and third exemplary embodiments.

During the injection process, the actuating piston 6 is accelerated in the conveying direction 13 by the magnet 8, wherein it stores kinetic energy during an acceleration phase. At the end of the acceleration phase, the actuating piston 6 hits the metering piston 28 and transmits its kinetic energy to it, as a result of which fuel is displaced from the pressure chamber 21 to the injection nozzle 3. Is set by the bias of the compression spring 47 in the delay chamber 42

Delay pressure P _{v reached} in the pressure chamber 21, fuel escapes into the delay chamber 42, the delay piston 46 being inserted into the delay chamber 42. As a result, the pressure build-up in the pressure chamber 21 and consequently in the high-pressure line 2 is delayed, so that the pressure does not increase suddenly, but rather increases gradually. The deceleration process ends when the deceleration piston 46 strikes the bottom wall 45. The delay time is determined by the spring hardness of the spring 47 and the stroke of the delay piston 46.

The delay pressure is preferably in the range of P = ¹ / 2P _nozzle to P _v = pouse wherein P _nozzle is the nozzle opening pressure of the injection nozzle. 3 The spring hardness of the compression spring 47 is selected so that the deceleration process lasts at least during the opening phase of the injection valve. The spring hardness of the compression spring 47 and the stroke of the delay piston 46 are preferably chosen so that the delay _{piston 46} strikes the bottom wall 45 at a final pressure P _En de of _1.5P _Du to 3P _DuS e.

The process of building up pressure in the fuel in the pressure chamber 21 and the high-pressure line 2 can be divided into three phases:

1.) First, the fuel is pressurized until the pressure assumes the deceleration pressure P. During this pressure increase, because of the incompressibility of the fuel, the metering piston 28 carries out only a minimal movement, which is why this pressure increase takes place suddenly.

2.) When the deceleration pressure P is reached, the deceleration phase begins, during which the further pressure build-up is delayed. During this delay phase, the injection valve opens, the opening process not taking place suddenly, but continuously over a certain period of time. Since the pressure build-up is delayed during the opening process of the injection valve, it is achieved that a smaller proportion of pressure energy is reflected at the only partially opened injection nozzle, which slows down the movement of the metering piston during the subsequent reflection and would lead to pressure fluctuations during the injection process.

3.) The spring hardness of the compression spring 47 and the stroke of the delay piston 46 is selected, for example, so that the deceleration process is completed immediately after the injection valve is fully opened, so that the further pressure rise takes place again at the maximum rate of increase. This delay device delays the build-up of pressure during the opening process of the injection nozzle, thereby preventing pressure waves from being reflected at the only partially opened injection nozzle and braking the movement of the metering piston. This results in better energy transmission and a more uniform pressure level during the injection process.

This delay device can be provided in all of the exemplary embodiments of the present application, it being arranged opening to the pressure chamber 21 or to the high-pressure line 2; however, an arrangement as close as possible to the metering piston is preferred.

The delay device can also be replaced with a e.g. between the actuating piston and the metering piston arranged spring or damping element that delays the energy transfer from the actuating piston to the metering piston.

FIG. 9 shows an eighth exemplary embodiment of the fuel injection device according to the invention. It has essentially the same structure as the sixth embodiment, which is why the same parts are denoted by the same reference numerals and a detailed description can be omitted.

The eighth exemplary embodiment differs from the seventh exemplary embodiment in that the actuating piston 6 bears directly against the metering piston 28 and in the pump device 4 only a single spring 20 is arranged between the actuating piston 6 and the guide bush 15 rearward in the conveying direction 13. The spring 20 acts on the actuating piston 6 together with the metering piston 28 in the conveying direction 13, that is to say in the direction of the pressure chamber 21.

The actuating piston 6 and the metering piston 28, which acts as a storage piston, execute both the storage stroke and the delivery stroke together. In this embodiment, the actuating piston 6 and the metering piston 28 can be formed in one piece.

A pump-nozzle system with a ninth exemplary embodiment of the fuel injection device according to the invention is shown in FIG. 10. The structure of this fuel injection device corresponds essentially to that of the fifth

Embodiment and differs from this only in the design of the

Pump device 4.

The pump device 4 is operated pneumatically. It has a pump housing 60. A hollow cylindrical actuating piston chamber 62 is formed in the pump housing 60, in which an actuating piston 6 is slidably arranged. The actuating piston 6 is a hollow cylindrical piston which is open on one end face and has a piston head 63 and a piston wall 64. The piston wall 64 bears in a form-fitting manner against the inner wall of the actuating piston chamber 62.

An actuating piston spring 67 is inserted between the piston head 63 and the front end of the actuating piston chamber 62 in the conveying direction 13, which acts on the actuating piston 6 with a force in the conveying direction 13.

A storage bore 65 opening into this is coaxial with the actuating piston chamber 62. The storage bore 65 is arranged in the conveying direction 13 in front of the actuating piston chamber 62 and has a smaller diameter than the actuating piston chamber 62, so that an annular step 66 is formed at the mouth area of the storage bore 65 with respect to the actuating piston chamber 62. The actuating piston 6 is arranged with its piston head 63 pointing in the direction of the storage bore 65. A massive, bolt-shaped storage disk 7 is stored in the storage bore 65.

Immediately adjacent to the ring step 66 is a control opening 68 which opens into the actuating piston chamber 62. A control valve 70 is arranged at the control opening 68 and is connected to a combustion chamber via a pneumatic line. The control valve 70 is a known electromagnetically operated pneumatic valve for opening and closing a passage.

This pneumatically operated pump device 4 is placed with the storage bore 65 opening outward on the pump housing 60 at an opening of the region delimiting the pressure chamber 21 in the rest of the housing body 11, so that the pressure chamber 21 extends into the inner region of the storage bore 65 and it relates to the Pump device 4 is delimited by the inner wall of the storage bore 65 and the front end face of the storage piston 6 in the conveying direction 13. The mode of operation of the sixth exemplary embodiment of the fuel injection device according to the invention is explained below.

After an injection process, the fuel injection device is in the state shown in FIG. 10, that is to say that the actuating piston 6 is pressed by the actuating piston spring 67 against the ring stage 66 and the metering piston 28 in its initial state, in which it is released from the pressure chamber 21 by the metering spring 34 is pressed away against the rear guide bush 32.

At the end of a combustion process in the combustion chamber of the internal combustion engine, the control valve 70 briefly opens the control opening 68, as a result of which a gas pressure is formed between the ring stage 66 and the piston crown 63, which lifts the actuating piston 6 against the action of the actuating piston spring 67 from the ring stage 66. The storage piston 7 is pressed into the storage bore 65 by this gas pressure, but due to the different cross sections, the force acting on the storage piston 7 is considerably less than the force acting on the actuating piston 6.

The metering process is only started after the pump device 4 has been pretensioned by means of the gas pressure. In this case, the metering device 5 delivers fuel into the pressure chamber 21 in an identical manner as in the fifth exemplary embodiment, as a result of which the storage piston 7 in the storage bore 65 is displaced in the direction opposite to the conveying direction 13 and thus against the effect of the gas pressure (= storage stroke). The fuel stored in pressure chamber 21 cannot flow out because of the overflow valve 25, which is why the accumulator piston 7 is held in the position of the accumulator stroke and a precisely defined amount of fuel is stored.

For the injection process, the control valve 70 opens the control opening 68, as a result of which the gas located in the actuating piston chamber 62 flows out, the actuating piston 6 is accelerated in the conveying direction 13 by the actuating piston spring 67 and presses the accumulator piston into the accumulator bore after an acceleration phase. When the actuating piston 6 hits the ring step 66 or the accumulator piston 7 on the housing body 11, the conveying process is stopped, the conveying stroke in turn corresponding exactly to the accumulator stroke. Since the storage stroke can be set exactly by the metering device 5, a predetermined variable fuel quantity can be metered in the pump-nozzle system independently of signs of aging. FIG. 11 schematically shows a pump-nozzle system with a tenth exemplary embodiment of a pneumatically driven fuel injection device according to the invention.

In this injection device, the metering piston 28 and the actuating piston 6 are arranged in a line similar to the sixth embodiment. This injection device has an essentially tubular housing body 11. At the rear end in the direction of injection 13, the housing body is closed with an end plate 71. At the front end region of the tubular housing body 11 in the injection direction 13, a connection opening 22 is provided for connecting the high-pressure line 2 leading to the injection nozzle 3.

A stop bushing 17 is provided adjacent to the connection opening 22 and is inserted in a passage delimited by an inwardly projecting ring web. The metering piston 28 in turn has a tubular armature body 29 with a guide pin 30 protruding on its two end faces. With the region of the guide pin 30 pointing forward in the injection direction 13, the metering piston 28 is supported in the stop bushing 17. A standing pressure valve 24 is arranged between the stop bushing 17 and the connection opening 22.

In the area of the stop bushing 17, a fuel supply 58 opens into the pressure chamber 21 between the auxiliary pressure valve 24 and the metering piston 28. A check valve 39 is arranged in the fuel supply 58, which prevents backflow into a fuel supply line 38 connected to the fuel supply 58.

The actuating piston 6 is located in the tubular housing 11 between the metering piston 28 and the end plate 71. The actuating piston 6 has an approximately cup-shaped body with a jacket wall 72 and a bottom wall 73. With its jacket wall 72, the actuating piston 6 is positively supported in the tubular housing 11 and is arranged with its bottom wall 73 in the injection direction 13 to the rear. In the cylindrical recess delimited by the cup-shaped actuating piston 6, the metering piston 28 is supported with its guide pin 30 projecting rearward in the injection direction 13.

A metering spring 34 is inserted between the bottom wall 73 and the metering piston 28.

At the rear jacket area, the actuating piston 6 has a recess in which an actuating piston spring 67 sits, which is supported on the end plate 71 of the housing 11. To actuate the metering piston 28, an electromagnet 8 enclosing the housing 11 is arranged on the rear region.

A pneumatic opening 74 is formed on the tubular housing 11 adjacent and in the injection direction 13 on the rear of the annular web 16. On the outside, a control valve 70 is attached to the housing 11, which can release and shut off a pneumatic connection between the pneumatic opening 74 and a compressed gas reservoir. The control valve 70 is a known electromagnetically operated pneumatic valve for opening and closing a passage. Gas under pressure can thus be supplied into the space in which the metering piston 28 and the actuating piston 6 are located, the armature chamber 9.

The metering piston 28 has at least one longitudinal groove 75 in the jacket area of its armature body 29, through which a gas entering the armature chamber can be passed on to the area rearward from the metering piston 28.

The mode of operation of this tenth exemplary embodiment is explained in more detail below.

During a metering process, the metering piston 28 is actuated by the magnet 8 counter to the injection direction 13, so that fuel is drawn in from the fuel supply and stored in the pressure chamber 21 in the area between the standing pressure valve 24 and the metering piston 28. Since the fuel cannot escape from the pressure chamber 21 because of the check valve 39, the metering piston 28 is fixed in its position.

To actuate the metering piston 28, the actuating piston 6 is prestressed by means of a gas under pressure. The gas is supplied to the armature chamber via the pneumatic opening 74 and is introduced into the area between the metering piston 28 and the actuating piston 6 through the longitudinal groove 75 made in the metering piston 28, so that the actuating piston 6 presses backward against the actuating piston spring 67 due to the increased gas pressure and the actuating piston spring 67 is biased. The metering piston remains in its position since it is acted upon both by the metering spring 34 and by the gas under pressure in the injection direction 13 and its movement in the injection direction 13 is blocked by the fuel in the pressure chamber 21.

When the control valve 70 is opened, the gas can escape from the armature space, as a result of which the actuating piston 6 is injected due to the spring tension of the actuating piston spring 67. Direction is accelerated until it strikes the metering piston 28 and transmits its energy to it in order to spray off the fuel in the pressure chamber 21.

The biasing of the actuating piston 6 can also take place before the actuation of the metering piston 28 by means of the magnet 8, but the sequence described above, in which the metering process is carried out first and then the biasing of the actuating piston, is preferred, since then the metering piston 28 only works against the actuating piston spring 67 during metering and does not also have to work against an increased gas pressure.

The combustion chamber of the internal combustion engine equipped with the PDS system according to the invention can be used as the gas pressure reservoir. 12 shows the pressure profile during a work cycle in a combustion chamber. In the area before top dead center OT, the pressure gradually increases from atmospheric pressure to a compression pressure due to the compression generated by the piston movement. After ignition, which is usually triggered shortly after reaching top dead center, the pressure suddenly rises to a multiple of the compression pressure and then drops sharply due to the piston movement, with the pressure in the combustion chamber except for after opening the exhaust valve Atmospheric pressure decreases.

To actuate the pneumatic injection device according to the invention, gas can be drawn off at about the level of the compression pressure during the pressure drop (I in FIG. 12) and fed to the injection device for prestressing the actuating piston.

The gas flowing out when the injector is discharged is e.g. fed back to the combustion chamber (II in FIG. 12), the combustion chamber pressure at this point in time being lower than the storage pressure in the injection device. The time of unloading the injection device is determined by the time of the injection process, so that it always coincides with the pressure increase in a single-cylinder engine. In the case of a multi-cylinder engine, the injector assigned to a specific cylinder can be controlled with the gas from another cylinder, so that the discharge process of the injector can coincide with the phase during which the atmospheric pressure prevails in the combustion chamber.

An additional valve can be provided in the pneumatic connecting line between the combustion chamber and the injection device, with which the gas can be discharged when the injection device is discharged into a room with a low, ie, for example, atmospheric pressure. Instead of the combustion chamber, the crankcase can be used as a gas pressure reservoir in 2-stroke engines, in which the air contained therein is cyclically compressed due to the piston movement.

These pneumatically operated injection devices are primarily intended for internal combustion engines that do not have their own electrical system, with which electrical energy is provided in sufficient capacity. In these devices, the main energy contribution, namely the movement of the actuating piston, is carried out by means of pneumatically transmitted energy, whereas the control functions, which have only a low energy consumption but have to be carried out very precisely, are controlled electrically.

A preferred metering device is shown in FIGS. 13a and 13b. The same parts as in the metering devices described above are provided with the same reference numerals. This metering device 5 in turn has a tube section 26 which is enclosed by a magnet 35. The tube section 26 and the magnet 35 are surrounded by a housing 36.

A metering piston 28, which is formed from an armature body 29 and a piston body 30a, is supported in the tube section 26. The piston body 30a is rod-shaped with a smaller diameter than the armature body 29 and is arranged coaxially in front of the armature body 29 in the conveying direction 76 of the metering device 5. The front end of the piston body 30a is slidably mounted in a guide bush 31. At its rear end, the piston body 30a has an annular web 77 projecting radially outward, a metering spring 34 being clamped between the annular web 77 and the guide bushing 31.

At the rear of the pipe section 26 in the conveying direction 76, a Lekagerrohr 78 is inserted. The Lekagerohr 78 extends through an opening in the housing 36 to the outside and forms with its front-facing end face a stop 79 for the metering piston 28. The metering piston 28 is in its initial position, i.e. in the position displaced backwards due to the spring force of the metering spring 34, on the stop 79.

The guide bush 31 has at its front end in the conveying direction 76 a radially outwardly projecting annular disk 79. The ring disk 79 is sealed on its rear side with a sealing ring against the pipe section 26 and has on the front side in the area the through opening has a flat, approximately spherical recess 80. In the conveying direction 76, the recess 80 is preceded by a valve device 81.

The valve device 81 has a circular metal disk 82 which bears directly against the annular disk 79 of the pipe section 26 and a circular valve disk 83. The metal disc is provided with an inlet hole 84 and an outlet hole 85. The inlet hole 84, the outlet hole 85, the spherical recess 80 and the passage of the guide bush 31 which extends as far as the metering piston delimit a valve chamber 86.

The valve disk 83 is preferably a thin metal plate made of spring steel, which is preferably coated on both sides with rubber or plastic. On the valve disk 83, an inlet tongue 87 and an outlet tongue 88 are cut free with a narrow u-shaped cut. The two disks 82, 83 are held by a housing cover 89 which is detachably attached to the housing 36 and has a circular recess in which the two disks 82, 83 are arranged. A fuel supply channel 90 is formed in the housing cover 89 and opens into the area of the inlet tongue 87 on the valve disk 83. On the fuel feed channel 90, a fuel feed nozzle 91 protrudes radially outward on the housing cover 89 and to which a fuel feed line can be connected. In the housing cover 89, a fuel outlet duct 92 is also introduced, which opens at the valve disk 83 with an opening 93 in the region of the outlet tongue 88.

The opening 94 of the fuel supply channel 90 opening at the inlet tongue 87 is so small that it can be completely covered by the inlet tongue 87. That is, the opening 94 is within the clearance of the inlet tongue (Fig. 13b). The inlet opening 84 of the metal disk 82 is so large that it completely surrounds the inlet tongue 87. When the inlet tongue 87 is in the disk plane, it completely covers the fuel supply channel 90, so that the supply of fuel is interrupted. Since the inlet opening 84 of the metal disc 82 completely surrounds the tongue 87, the inlet tongue 87 can be bent into the inlet opening 84 so that it clears a passage between the fuel supply channel 90 and the valve chamber 86. The inlet tongue 87 thus forms, with the openings 84 and 94, an inlet valve 95 designed as a check valve, which prevents a fuel flow from the valve chamber 86 into the fuel supply channel 90.

The outlet opening 85 of the metal disk 82, on the other hand, is so small that it lies within the cutout of the outlet tongue 88 (FIG. 13b), ie the outlet opening is so small that it can be completely covered by the outlet tongue 88. If the outlet tab 88 in the disc plane, it completely covers the outlet opening 85, so that the passage from the valve chamber 86 to the outlet channel 92 is interrupted.

The opening 93 of the outlet channel 92 is larger than the free cut of the outlet tongue 88, so that the outlet tongue 88 can be bent into the opening 93 and opens a passage between the valve chamber 86 and the outlet channel 92. The outlet tongue 88 thus forms with the openings 85, 93 an outlet valve 96 designed as a check valve, which prevents fuel flow from the outlet channel 92 into the valve chamber 86.

The mode of operation of this metering device 5 is explained below.

When the metering piston 28 is actuated from its starting position by the magnet 35, ie the metering piston is moved in the conveying direction 76, it displaces fuel from the valve chamber 86 through the outlet valve 96 into the outlet channel 92. During the fuel displacement, the inlet valve 95 locks. During the return movement of the metering piston into its starting position, fuel is drawn in from the fuel supply channel 90 through the inlet valve 95. Here, the exhaust valve 96 blocks.

A very small valve chamber 86 is obtained by forming the two valve tongues 87, 88 on a single disk 83. This means that with this metering device 5, a pump device with an extremely small damage space was created. Large harmful spaces are disadvantageous in the case of pumping devices for conveying liquids, because if they are not completely filled with liquid, the pump stroke may only compress and relax an air column without liquid being pumped.

This special configuration of the metering device is not only advantageous in the case of injection devices, but can also be used in any other reciprocating piston pump device. However, this pump arrangement is particularly advantageous as a metering device for injectors, since the pump device 4 can be flooded with an extremely small clearance, the pump device 4 not having to be actuated during flooding, so that its clearance (= pressure chamber 21) can be designed in any size .

In some of the exemplary embodiments of the pump devices according to the invention described above, a delay device is provided (FIGS. 2, 4, 6, 8). This delay device represents an independent inventive idea that can also be implemented in a pump device without a metering device. 14 to 17 such pump devices are shown. These pump devices are as Injectors designed. You can of course also fund other projects

Fluids, especially liquids, can be used.

14 schematically shows an eleventh embodiment of an injection device according to the invention in cross section. The same parts are provided with the same reference numerals as in the exemplary embodiments described above.

This injection device has an approximately tubular housing 11, which is closed at the rear end in the conveying direction 13 by a housing cover 14. The front end in the conveying direction 13 forms a connection opening 22 for receiving a pressure line 2, which leads to an injection nozzle 3.

Inside the tubular housing 11, a tubular guide bush 15 is inserted at the rear end, in which an armature 6 is slidably mounted with a guide pin 55 formed on its rear end face. The armature 6 has an essentially cylindrical base body 52 which bears with its outer wall against the inner wall of the tubular housing 11. The guide socket 55 is attached to the rear end face of the base body 52. On the front end side of the armature 6 in the conveying direction, a blind hole-like, approximately hollow cylindrical recess 100 is made. A distance from the front end face of the armature 6, a guide region 101 is formed in the recess 100 by a concentric guide recess with a larger inner diameter than the rest of the recess 100. The guide area 101 is thus delimited both in the conveying direction 13 and counter to the conveying direction 13 by an annular edge 102, 103 in each case.

A conveying piston 104 is arranged upstream of the armature 6 in the conveying direction 13, and its rear end projects into the recess 100 of the armature 6. The rear end of the delivery piston 104 forms a guide part 105 which has an outwardly projecting ring web 106 which engages in the guide region 101 of the armature 6. The guide part 105 is displaceably mounted in the recess 100, the relative movement between the armature 6 and the delivery piston 104 being limited by the ring edges 102, 103, which serve as stops for the ring web 106 of the guide part 105. The delivery piston 104 corresponds to the storage piston 7 of the second exemplary embodiment (FIG. 2).

Between the guide part 105 of the delivery piston 104 and the bottom of the blind hole-like recess 100 of the armature 6, a compression or coupling spring 41 is pre-tensioned. set, which presses the guide part 105 of the delivery piston 104 against the front ring edge 103.

The front end of the delivery piston 104 in the conveying direction 13 is supported in a guide bushing 17. The guide bushing 17 is inserted into an annular web 16 projecting inwards from the inner wall of the tubular housing 11. The annular web 16 delimits an anchor space 9 formed in the tubular housing 11 between it and the rear cover 14, in which the anchor 6 is arranged displaceably.

The guide bushing 17 protrudes a little towards the rear into the armature space 9 and has at its front end an outwardly projecting annular web 17a with which it engages behind the annular web 16 of the housing 3.

A return spring 50 is arranged between the ring web 16 of the housing and the armature 6 and presses the armature 6 against the conveying direction 13. The return spring 50 is a very soft spring, which is used without or only with very little pretension, so that it only overcomes the frictional forces when the armature 6 is reset, but does not provide any appreciable resistance to the movement of the armature 6 in the conveying direction 13.

In the area of the ring land 16, a fuel supply opening 107 is introduced, which extends radially inward from the outside through the housing 11 and the guide bushing 17. On the outside, a connecting piece 38 for connecting a fuel supply line (not shown) is formed on the fuel supply opening 107 on the housing 11. A check valve 39 is arranged in the fuel supply opening 107 and blocks a fuel flow back into the fuel supply line.

At the front end of the guide bushing 17 in the conveying direction 13, a parking pressure valve 24 is arranged, which blocks the connection to the injection nozzle 3, provided that the pressure applied to the parking pressure valve 24 is less than a certain passage pressure P _through . The passage pressure is generally considerably lower than the opening _pressure P _{DuSe of} the injector 3 at which the injector 3 opens.

The area delimited by the check valve 39, the standing pressure valve 24 and the front face of the delivery piston 104 in the conveying direction forms a pressure chamber 21. In the area of the armature space 9, an electromagnet 8 for actuating the armature 6 is arranged on the outside of the housing 11.

The mode of operation of this eleventh exemplary embodiment of the invention is explained below.

In the starting position shown in FIG. 14, the armature 6 rests with its rear end face on the guide bush 15 and the delivery piston 104 rests with its guide part 105 on the front ring edge 103 of the armature 6.

The armature 6 is driven by the electromagnet 8 in the conveying direction 13, the delivery piston 104 being first pressed by the armature 6 against the fuel located in the pressure chamber 21 and in the pressure line 2 without the relative position thereof changing (at a in FIG. 19 ). The delivery piston 104 pressurizes the fuel, wherein when the passage pressure P is _{reached by} the auxiliary pressure valve 24, the auxiliary pressure valve 24 opens and releases the connection to the injector 3. When the opening pressure P _Du se of the injector 3 is reached, the injector 3 opens and fuel is injected from the injector 3 into the combustion chamber (not shown). As long as the pressure in the fuel is lower than the nozzle opening pressure, there is no relative movement between the delivery piston 104 and the armature 6 due to the prestressing of the compression spring 41. The pressure build-up to the nozzle opening pressure P _Duse occurs almost instantaneously, because of the incompressibility of the fuel anchor and delivery piston existing unit to reach the nozzle opening pressure P _nozzle performs only a minimal movement.

According to the invention, the delivery piston 104 is pushed from a certain pressure in the pressure chamber 21 or in the high-pressure line 2, which is referred to below as the deceleration pressure P, into the recess 100 against the spring action of the compression spring 41, whereby the further pressure build-up is delayed.

This delay corresponds to pressure P _against the biasing force F with which the pressure spring 41 between the feed piston 104 and the armature is clamped 6, divided by the cross sectional area A i _ben _Kθ of the delivery plunger 104:

Since the preload force can be set precisely, the deceleration pressure can also be set exactly.

The deceleration pressure is preferably set to the opening pressure of the injection nozzle (Pv = P _DUSΘ ), so that the pressure rise is reduced when the opening pressure P _{DuSe of} the injection nozzle is reached. As a result, the fuel in the pressure chamber 21 and in the pressure line 2 is first compressed to the nozzle opening pressure with a small movement of the armature 6 and the delivery piston 104 in the delivery direction 13.

When the nozzle opening pressure P _Duse is reached, the opening of the injection nozzle 3 is initiated.

After reaching the nozzle opening pressure, the armature 6 moves in the conveying direction 13 at a guide speed. The conveying piston 104 is moved at a reduced speed in the conveying direction 13, since the conveying piston immerses into the recess of the armature 6 against the spring action of the spring 41 (at b in Fig. 19). There is therefore a relative speed between the delivery piston 104 and the armature 6. This reduced speed of the delivery piston 104 compared to the armature 6 reduces the energy transfer from the armature 6 to the delivery piston 104 or to the fuel.

As a result, the kinetic energy introduced into the armature is not reduced by the not yet fully opened injection nozzle, and the generation of pressure waves reflected back and forth between the injection nozzle 3 and the delivery piston 104 is kept low.

The spring hardness of the compression spring 41 and the stroke of the guide part 106 in the guide region 101 are preferably dimensioned such that the pressure build-up is delayed at least during a first part of the opening phase of the injection nozzle 3, during which the injection nozzle 3 opens only slowly. The deceleration phase is then to be completed, that is to say that the guide part 105 of the delivery piston 104 abuts against the ring edge 102 of the armature 6, which is at the rear in the direction of travel 13, when the spring force exerted by the compression spring 41 exerts an _end deceleration pressure P _end that corresponds to the 1.5 to 3 times the nozzle opening pressure (P _En de = 1, 5PDuse to 3P _Du se) corresponds. The greater the final deceleration pressure, the slower the response of the injector, but the more pressure valleys can be compensated for during the injection process. After the delay phase, the delivery piston 104 is at the guide speed of the

Armature 6 moves in the conveying direction 13, so that the pressure at the maximum rate of increase to

Maximum pressure P _MAX continues to increase (at c in Fig. 19).

The _nozzle opening pressure P _nozzle is typically in the range from 1 to 5 MPa and the cross-sectional area A oi e _{n of} the delivery piston 104 is usually 5 to 20 mm ² . In the exemplary embodiment shown in FIG. 14, the _nozzle opening pressure P _nozzle = 2 MPa and the cross-sectional area 12 mm ² , so that the retarding pressure P is set to the opening pressure of the injection nozzle 3 with a spring preload force of F _before = 24 N.

The pressure in the fuel to be pumped rises to the maximum pressure P _AX , which is higher than in comparable conventional injection devices, since only a relatively small amount of energy is introduced during the opening phase of the injection nozzle, so that a higher energy yield is achieved and less disturbing pressure reflections are generated .

The fuel is then injected at an approximately constant pressure P _MAX , since the reflections of the pressure waves are largely avoided (at d in FIG. 19). Should pressure troughs nevertheless occur (dashed line at t ₂ in FIG. 19), the energy stored with the pressure spring 104 ensures that these do not drop below the nozzle opening pressure, since such deep pressure troughs are compensated for by the energy stored in the pressure spring.

In the injection device according to the invention, during the opening phase of the injection valve, the armature 6 does not work against the pressure waves running counter to the direction of delivery and the fuel column braked by the not yet fully opened injection nozzle, but rather only transfers the energy introduced into it to the fuel column after the injection nozzle has opened completely is.

Another significant advantage of this injection device according to the invention is that at the end of the injection pulse, when the force exerted by the electromagnet on the armature / piston unit becomes lower and the delivery pressure generated thereby decreases, the energy stored in the compression spring 41 drives the delivery piston 104 until it abruptly strikes with its guide part 105 on the front ring edge 103 of the armature 6 and is stopped. The injection pulse is thus abruptly ended and has an abrupt drop at its end (at e in FIG. 19). As a result, exact pressure conditions are achieved at the end region of the injection pulse, as a result of which both the spray behavior (uniform droplet size) and the meterability of the fuel are significantly improved. In the above embodiment, the deceleration _{pressure is} set to the opening _{pressure of} the injection nozzle (P _v = P _DUSΘ ) - this is an advantageous embodiment. However, the invention is not limited to this. The deceleration pressure should be at least half the opening pressure of the injection nozzle (P _v = V∑P _D us _e ) - because a so-called surf effect in the area of the injection nozzle 3, that is to say due to pressure waves overlapping, can lead to a local pressure increase which can be up to can be about twice the regular pressure in the pressure line 8. By such a pressure increase, the injection nozzle 3 can be opened before the actual opening pressure is reached, so that a delay in the further pressure build-up is then expedient in order to achieve the best possible energy transfer.

In order to obtain as few reflections from the pressure wave as possible, the deceleration pressure P _v should be as low as possible. If the deceleration pressure P _{v is} too low, however, the response behavior of the pump-nozzle system is impaired. A deceleration _pressure in the range from P = ¹ 2P _use to Pv = P _DUSΘ represents a suitable compromise between the requirements for reducing the generation of pressure reflections and the response.

A twelfth exemplary embodiment of an injection device according to the invention is shown in FIG. 15.

This embodiment has essentially the same structure as the eleventh embodiment, which is why the same parts are provided with the same reference numerals.

Compared to the eleventh embodiment, it differs only in the design of the recess 100 in the armature 6 and the guide part 105 of the delivery piston 104.

At the bottom of the blind hole-like recess 100, a flat cylindrical damping recess 108 with a jacket wall 109 is made. On the rear side of the delivery piston 104 in the conveying direction 13, a flat-cylindrical damping punch 110 is formed with a lateral surface 111, which has essentially the same cross-sectional shape as the damping recess 108, so that the damping punch 110 fits into the damping recess 108 with little play .

In this exemplary embodiment, no compression spring is provided between the delivery piston 104 and the armature 6. The ring web 106 of the delivery piston 104 is provided with longitudinal grooves (not shown), so that the delivery piston can be moved in the fuel-filled recess 100 of the armature 6 essentially without resistance as long as the damping plunger 110 is located outside the damping recess 108. The resistance-free displacement path X is shown in FIG. 15.

The operation of the twelfth embodiment will be explained below.

The armature 6 is moved in the conveying direction 13 by the electromagnet 8, wherein it is accelerated along the displacement path X for storing kinetic energy essentially without resistance. After the displacement path X has been covered, the damping punch 110 penetrates into the damping recess 108, a narrow gap being formed between the jacket wall 109 of the damping recess 108 and the jacket surface 111 of the damping punch 110, so that the gap between the damping punch 110 and the damping recess 108 existing fuel can only escape gradually and the damping plunger 1 10 can only enter the damping recess 108 with a delay due to the damping. As a result, the kinetic energy is transmitted from the armature 6 to the delivery piston 104, the damping not transmitting the kinetic energy abruptly but gradually over the period of time Δt that the damping plunger 110 requires to penetrate completely into the damping recess 108.

This causes a correspondingly delayed transfer of the energy from the delivery piston to the fuel to be delivered over the time period Δt, as a result of which the pressure build-up does not occur suddenly, but with a delay. This delay occurs from the beginning of the injection pulse and lasts at least until the injection nozzle 3 is completely open. The duration of the delay can be determined by the depth of the damping recess 108 or the gap width between the damping plunger 110 and the damping recess 108. This delay in energy transmission prevents reflections from the only partially opened injection nozzle 3 and the disadvantages associated therewith.

In the above exemplary embodiment, the delay device for delaying the pressure build-up is a mechanical damping device consisting of the damping plunger 110 and the damping recess 108. Within the scope of the invention, the damping device can also be designed differently, for example from a plastically deformable damping plunger, which is found when the armature hits the armature The delivery piston is plastically deformed, thus delaying the build-up of pressure in the fuel. A thirteenth embodiment of the invention is shown in FIG. 16.

This embodiment is similar to the eleventh and twelfth embodiments, so that the same parts are given the same reference numerals.

The delivery piston 104 and the armature 6 are in this case made in one piece.

A passage 43 leading to a delay chamber 42 opens onto the pressure chamber 21. The delay chamber 42 is constructed in exactly the same way as that of the third (FIG. 4) and the seventh (FIG. 8) exemplary embodiment.

The operation of this thirteenth embodiment is explained below.

The armature / piston unit is moved by the magnet 8 in the conveying direction 13, as a result of which fuel is displaced from the pressure chamber 21 to the injection nozzle 3. If the deceleration pressure P set in the deceleration chamber 42 by the pretension of the compression spring 47 is reached in the pressure chamber 21, fuel escapes into the deceleration chamber 42, the deceleration piston 46 being pushed into the deceleration chamber 42. As a result, the pressure build-up in the pressure chamber 21 and consequently in the high-pressure line 2 is delayed, so that the pressure does not increase suddenly, but rather increases gradually. The deceleration process ends when the deceleration piston 46 strikes the bottom wall 45. The delay period is determined by the spring hardness of the spring 47 and the stroke of the delay piston 46 in the delay chamber 42. In this way, reflections of the pressure waves are avoided in the same way as in the first exemplary embodiment described above, and the pressure curve shown in FIG. 19 is achieved.

The same rules described above with reference to the eleventh exemplary embodiment apply to the dimensioning of the prestressing force and the spring hardness of the compression spring 47 in order to delay the pressure build-up, to compensate for pressure fluctuations and to produce an abrupt pressure drop at the end of the injection pulse.

A fourteenth embodiment of the invention is shown in FIG. This embodiment is similar to the thirteenth embodiment, which is why the same parts are designated with the same reference numerals.

Compared to the thirteenth embodiment, the fourteenth embodiment differs only in the design of the armature / piston unit. The armature 6 and the delivery piston 104 are designed as separate components, the armature 6 consisting of a cylindrical base body 52 with a guide connection 55 attached to the rear end side with respect to the delivery direction 13. The armature is in turn pressed against the conveying direction 13 by a return spring 50, which is supported on the ring web 16 projecting inward into the housing 11. The return spring 50 is used without or only with a slight pretension, so that it provides practically no resistance to the armature 6 when moving in the conveying direction and this can be accelerated essentially without resistance when actuated by the electromagnet 8.

The delivery piston 104 is slidably mounted in the guide bushing 17 inserted in the ring web 16 in the axial direction. The delivery piston 104 is essentially rod-shaped with an annular web 1 12 projecting radially outward at its front end, which engages behind the front end of the guide bushing 17 in the delivery direction 13. Between the front end of the delivery piston 104 and the inner wall of the pressure chamber 21 opposite the delivery piston 104, a delivery piston return spring 113 is inserted, which presses the delivery piston 104 against the delivery direction 13, so that in the initial position shown in FIG. 17, the ring web 1 12 on the front Front face of the guide bush 17 strikes.

In the starting position, in which both the delivery piston 104 and the armature 6 are pressed against their respective rear stops by the respective return springs 50, 113, the armature 6 and the delivery piston 104 are spaced apart by a distance X.

A delay chamber 42, which is identical to that in the thirteenth exemplary embodiment and in which a delay piston 46 acted upon by a compression spring 47, opens onto the pressure chamber 21.

The method of operation of the fourteenth embodiment essentially corresponds to that of the thirteenth embodiment, but when the magnet 8 is excited, the armature 6 alone is accelerated essentially without resistance. After the armature 6 has covered the path X, it strikes the delivery piston 104 and suddenly transfers its kinetic energy to the delivery piston 104. The delivery piston 104 displaces the fuel in the pressure chamber 21, the further one after reaching the deceleration pressure P _v Pressure build-up as in the thirteenth exemplary embodiment is delayed by the delay device (delay chamber 42, delay piston 46, compression spring 47). This exemplary embodiment thus combines the solid-state energy storage principle known from the prior art and the delay in pressure build-up according to the invention.

In summary, it can be stated that a delay in the pressure build-up achieves a higher energy transfer in reciprocating pumps with non-positively guided armature / piston units, in particular when the pressure build-up occurs essentially suddenly, with the risk of generating pressure waves which cannot be controlled.

In some of the exemplary embodiments described above, the metering device is in each case a reciprocating piston pump which, during the metering process, pumps fluid into and into the pressure chamber and thus displaces the accumulator piston by one accumulator stroke. The invention is not restricted to this type of metering device; rather, it is also possible, e.g. to provide a further electromagnet which moves the storage piston directly, i.e. that the storage piston is an armature to this further electromagnet.

Claims

claims

1. Pump device with a pump device (4) designed as a reciprocating piston pump that displaces fluid by means of a reciprocating piston (6, 7), a stop element (17, 18) that limits the delivery stroke of the reciprocating piston (6, 7) in the conveying direction (13), and an electrically and independently of the pump device (4) driven metering device (5) for fixing the amount of fluid to be injected by shifting the

Reciprocating piston (6, 7) relative to the stop element (17, 18) by a certain, variable storage stroke, which corresponds to the delivery stroke.

2. Pump device according to claim 1, characterized in that the reciprocating piston (6, 7) is formed in two parts from an actuating piston (6) and a storage piston (7), the storage piston (7) relative to the actuating piston (6) in the conveying direction (13 ) is upstream.

3. Pump device according to claim 1 or 2, characterized in that the metering device (5) is a separate conveying device which is formed separately from the pumping device (4) and which can convey fluid in a pressure chamber (21) arranged upstream of the pumping device (4), the pressure chamber (21) being delimited at its connection to a connection part (3) by a stand pressure valve (24) which only opens from a certain passage pressure, the passage pressure being dimensioned such that the stand pressure valve (24) at one of of the metering device (5) into the pressure chamber (21) fluid delivery does not open, whereas the standing pressure valve opens when the fluid is pumped with higher pressure by the pump device (4).

4. Pump device according to claim 1 or 2, characterized in that that the metering device (5) has an electromagnet and the reciprocating piston

(28) armature of this electromagnet is so that the reciprocating piston for executing the

Storage stroke is acted upon by the electromagnet with a force.

5. Pump device according to one of claims 1 to 4, characterized in that a plurality of metering devices (5) are provided for supplying a respective fluid to the pump device (4).

6. Pump device, in particular according to one of claims 1 to 5, with a pump device (4) designed as a reciprocating piston pump which displaces fluid by means of a non-positively guided reciprocating piston, characterized in that the pump device (4) has a delay device which is designed in such a way is that the energy transfer from the reciprocating piston (6, 7) to the fluid is delayed.

7. Pump device according to claim 6, characterized in that the reciprocating piston (6, 7) is formed in two parts from an actuating piston (6) and a storage piston (7), the storage piston (9) relative to the actuating piston (6) in the conveying direction (13) is arranged upstream, and the actuating piston (6) and the storage piston (7) are arranged displaceably relative to one another and are coupled to one another with a coupling spring (41).

8. Pump device according to claim 7, characterized in that the actuating piston (6) as a hollow body with a cylindrical jacket wall (6a), a rear wall in the conveying direction (13) (6b) and an inwardly projecting at the front end region in the conveying direction (13) Ring web (6c) is formed, the storage piston (7) has one end in the actuating piston (6) and has a radially outwardly projecting guide part (7b), the storage piston (7) with the guide part (7b) holding the ring web (6c) engages behind the actuating piston (6), and the coupling spring (41) is inserted between the end of the storage piston (7) which is supported in the actuating piston (6) and the bottom wall (6b) of the actuating piston.

. Pump device according to claim 6, characterized in that the deceleration device is formed by a deceleration chamber (42) opening onto the pressure chamber (21), in which a deceleration piston (46) is arranged, which on its opposite side from the pressure chamber (21) Side is supported by a spring (47).

10. Pump device according to one of claims 1 to 9, characterized by two metering devices (5) and a single pump device (4), the pump device (4) being double-acting and having two storage pistons (7, 7 ^' ), one of them in between arranged actuating piston (6) are actuated.

11. Pump device according to one of claims 1 to 10, characterized in that the pump device works according to the solid-state energy storage principle and has an accelerator body, which stores kinetic energy during an almost resistance-free acceleration phase, and a device interrupting the acceleration phase for generating a pressure surge by transmission the stored kinetic energy is provided on the fuel.

12. Chemoreactor for carrying out a chemical or biochemical reaction in a reaction chamber, characterized by a pump device according to one of claims 1 to 11 for supplying one or more fluids to the reaction chamber.

13. Fuel injection device for supplying fuel to a combustion chamber of an internal combustion engine, characterized by a pump device according to one of claims 1 to 11 and an injection valve

(3) which opens into a combustion chamber of an internal combustion engine.