WO2009092658A1

WO2009092658A1 - Compact injection device with simple construction

Info

Publication number: WO2009092658A1
Application number: PCT/EP2009/050405
Authority: WO
Inventors: Guenther Hohl; Harald Lang
Original assignee: Robert Bosch Gmbh
Priority date: 2008-01-23
Filing date: 2009-01-15
Publication date: 2009-07-30
Also published as: TW200946771A; DE102008005647A1; TWI439607B; CN101925735A; CN101925735B

Abstract

The present invention relates to an injection device comprising a fuel pump (20a), a pressure regulator (20b), an injector (20c) and an air adjuster (2Od), characterized in that the fuel pump (20a), the injector (20c) and the air adjuster (20d) are integral components of an injection module (2), the pressure regulator (20b) is an integral component of the injector (20c) and the fuel pump (20a) comprises a pump chamber (31) and the injection module (2) comprises an intake chamber (30; 50) and the intake chamber (30; 50) is connected to the pump chamber (31) by way of a free connection line (33; 51).

Description

description

title

Compact injector with simple construction

State of the art

The present invention relates to an injection device with a fuel pump, a pressure regulator, an injector and an air actuator in a compact design.

Injectors are known in the prior art in various configurations. Especially for cost and space reasons require small internal combustion engines, which have only one or only two cylinders and a small displacement, independent

Solutions. Areas of use of such small internal combustion engines are, for example, two-wheelers or tricycles or lawnmowers, etc. Known injectors usually comprise in a tank a fuel pump with a pressure regulator, the fuel pump injecting fuel at a predetermined pressure into a duct, e.g. a rail o.a., promotes. At the end of the line, an injector is arranged, which, controlled by a control device, injects fuel into a suction pipe or directly into a combustion chamber. However, such injectors are very expensive and especially expensive, so that they also make small internal combustion engines very expensive.

From EP 1 340 906 B1 a fuel injection device with electronic control is known in which an injector is arranged close to a pump piston. Further, in this case, a pre-pressure valve is provided for exerting an admission pressure on the fuel in an initial phase of a pressure stroke of the piston in the return line of the fuel to the tank. The admission valve evacuates a part of the fuel located in a pressure chamber in the return line. In this way, in particular the formation of vapor bubbles in the injector can be reduced. However, the structure is relatively complicated and the device takes up a large amount of space.

Advantages of the invention

The injection device according to the invention with the features of claim 1 has the advantage that it has a very compact structure. Furthermore, the injection device according to the invention can be produced in a particularly simple and cost-effective manner. This is inventively achieved in that the injection device is a fuel pump, a Pressure regulator for controlling an injection pressure, an injector and an air actuator comprises, which are integral components of an injection module. The injection module is a compact, small-sized component. The pressure regulator is an integral part of the injector. The fuel pump includes a pumping space in which the fuel is pressurizable and the injection module further includes an integrated suction space. The suction chamber is with the

Pump room connected via a free connection line. According to the invention, the term "free connection line" means a freely flowable line or bore, in which no valve or the like is arranged and thus fuel can flow freely from the suction chamber to the pump chamber or vice versa. The free connection line is preferably a bore of constant diameter. Thus, according to the invention, the number of parts

Injector can be reduced because it can be dispensed with a check valve between the suction and the pump chamber. The injection module can be completely pre-assembled so that it only needs to be connected to the necessary connections and can be installed directly into a vehicle. The components of the injection module are preferably arranged in a common housing of the injection module. In addition to the compactness of the

Injection module is another great advantage that other components for the injection module can be minimized.

The dependent claims show preferred developments of the invention.

Preferably, a total stroke of a piston of the fuel pump comprises a Ausschiebeteilhub and a Druckzeugsteilhub. The Ausschiebeteilhub and Druckzeugungsteilhub together form the total stroke of the piston. The Ausschiebeteilhub is preferably equal to or greater than the Druckzeugsteilhub. By this measure it is ensured that, if fuel vapor or other gases are present in the pump room, this means of

Ausschiebeteilhubs can be pushed out of the pump chamber and then only liquid fuel in the pump room is available for the Druckzeugungsteilhub. Furthermore, it is ensured by the Vorschalteteilhub before the Druckzeugsteilhub, that the piston of the fuel pump has a predetermined speed and thus brings sufficient momentum for the Druckzeugungsteilhub.

According to a further preferred embodiment of the present invention, a first check valve is arranged between the pumping space and a return space, and a connection to the tank is established via the return space. The check valve prevents that fuel vapor from the return chamber can inadvertently get into the pump chamber. Preferably, in the axial direction of the injection module, a pump chamber mouth of a connecting line between the pump chamber and the return chamber and closer to the injector is arranged as an opening of the free connecting line between the suction chamber and the pump chamber. This ensures that a control edge of the piston first closes the free connecting line between the pump chamber and the suction chamber and then only the connecting line between the pump chamber and the return chamber. As a result, fuel vapor can still be ejected via the first check valve in the return chamber and when the control edge of the piston has passed over the connecting line between the pump chamber and return chamber, only a pressure build-up in the pump chamber begins. This design ensures that during the pressure build-up phase no fuel vapor or other gases are present in the pump chamber, as these can be pushed out with certainty.

According to an alternative embodiment of the present invention, the injection device further comprises an annular space, in which a fuel supply line and a fuel return line open. The annulus is thus a combined intake and return space. It should be noted that the annular space does not necessarily have to be ring-shaped, but can assume any desired shape. However, an annular configuration of the annular space has the advantage that the injection device can be made very compact. Furthermore, a connecting line is provided, which connects the annular space with the pump space. The connecting line has a common branch line to the pump room and a branch to the annulus. The branching to the annulus comprises a first conduction region and a second conduction region. The first line region is arranged below the second line region and both line regions open into the annulus. Through the connecting line between the annulus and the pump chamber thus takes place a suction of fuel as well as a pushing out of possibly existing gases in the pump chamber. Only after a control edge of the piston has exceeded an opening of the connecting line, a pressure build-up in the pump chamber begins. When expelling gases that may be present, the gases are then discharged via the common branch line via the second line region into the annular space, since the second line region is arranged over the first line region.

So that the annular space has the largest possible volume, in the annular space preferably connected to a spring chamber, in which a return spring for an armature of the fuel pump is arranged.

More preferably, the first line region of the branch of the connecting line between the pump chamber and the annular space is arranged at the level of a bottom of the annular space. This ensures that during a suction phase over the first line area exclusively - A -

liquid fuel, which is completely outgassed (thick juice) is sucked. This ensures that no or only a minimal amount of vaporous fuel is sucked into the pump chamber.

Particularly preferably, the connecting line between the pump space and the annular space is designed such that the common stub opens into the middle of the branch between the first and second line region of the branch.

More preferably, the injection device comprises a central housing block in which the pumping space is formed. Connecting lines to the suction and / or return space or the annulus can be easily provided by drilling.

The injection device preferably comprises exactly one actuator, which simultaneously actuates the fuel pump and the aerator. As a result, in each case a separate actuator for the aerator or the fuel pump can be omitted in each case, so that the number of components is significantly reduced. Of course, this also results in a cost reduction. Thus, the common actuator assumes first the function of the pump drive and secondly the function of the actuator for the air actuator. The common actuator may perform a simultaneous actuation of the fuel pump and the air actuator, wherein the actuator comprises a coil, a first armature and a second armature. Here, the first armature is assigned to the air actuator and the second armature of the fuel pump, and both anchors can be activated by means of the common coil.

In order to provide as compact a structure as possible, the first armature is preferably a part of the air regulator and the second armature is a part of the fuel pump. In particular, the first armature is a valve member of the air regulator and the second armature is a piston of the fuel pump.

Furthermore, the present invention relates to an internal combustion engine which comprises exactly one cylinder or exactly two cylinders and a fuel injection device according to the invention. Particularly preferably, the internal combustion engine comprises a fuel tank, which above the

Injection module is arranged. As a result, in particular, the fuel pump can be designed very small.

drawing

Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings. In the drawing is: 1 shows a schematic view of a small motor with an injection device according to a first embodiment of the invention,

Figure 2 is a schematic view of the injection device according to the first embodiment, and

Figure 3 is a schematic view of the injection device according to a second embodiment.

Preferred embodiments of the invention

Hereinafter, a small motor 1 with an injection device according to the invention according to a first embodiment will be described in detail with reference to Figures 1 and 2.

Figure 1 shows schematically the structure of the small motor 1, which is designed as a single-cylinder engine. The small engine 1 comprises a cylinder 3, a reciprocating piston 4, a control unit 5 and a tank 6. The tank 6 is connected to an injection module 2 via a fuel supply line 6a. A fuel return line 6b goes from the injection module 2 back to the tank 6. As can be seen schematically from FIG. 1, the tank 6 is arranged above the injection module 2. As a result, the fuel passes through the fuel supply line 6a due to gravity to the injection module 2. The injection module 2 is shown very schematically and includes a fuel pump, an injector with integrated pressure regulator, and an air actuator, so that the injection module 2 is very compact.

The small engine 1 further comprises a throttle valve 7, which is arranged in a suction pipe 8. On the cylinder 3, a spark plug 9, an intake valve 10 and an exhaust valve 11 are further arranged. The reference numeral 12 designates a bypass line for air, which branches off air from the intake manifold 8 from a region in the flow direction of the air in front of the throttle valve 7 and leads directly to the integrated into the injection module 2 air actuator. An outlet 12z of the bypass line 12 opens in the intake manifold 8 behind the throttle valve. 7

The small engine 1 further comprises an exhaust pipe 13, which is released or closed by the exhaust valve 11. Further, an oxygen sensor 14 is provided on the exhaust pipe 13 which is connected to the control unit 5, and the control unit 5 is further provided with a cooling water sensor 15, an oil temperature sensor 16 and a sensor unit 17 for the

Detecting a throttle position, a temperature in the intake manifold 8 and a pressure in the intake manifold 8 connected. The control unit 5 controls the injection module 2 on the basis of the received signals. The injection device according to the invention is thus provided as an injection module 2 with a fuel pump, a pressure regulator, an injector and an air actuator, and can be designed to be particularly compact and physically small. Furthermore, the injection device according to the invention can be produced very inexpensively and in particular be pre-assembled in advance as a complete injection module, so that it only needs to be installed in the small engine 1 as a compact assembly. The integration of the four items fuel pump, pressure regulator, injector and air actuator thus a simple and inexpensive manufacturability is guaranteed. The fuel pump and the air actuator are actuated by a common actuator. As a result, the injection device 2 according to the invention can be used, for example, in small engines of two-wheelers or lawnmowers.

FIG. 2 shows the injection module 2 in detail. In the injection module 2, the fuel pump 20a, the pressure regulator 20b, the injector 20c and the aerator 2Od are integrated. For this purpose, a multi-part housing 25 (shown only schematically in FIG. 2) is provided. The pressure regulator 20b is part of the injector 20c. A common actuator simultaneously actuates the fuel pump 20a and the aerator 2Od. The common actuator comprises a coil 21, a first armature 22 and a second armature 23. As can be seen from Figure 2, the first armature 22 is part of the air actuator 2Od, the armature 22 has formed at one end a valve member 22a, which at a valve seat 12a of the bypass line 12, the bypass line 12 can release or close. The aerator 2Od is further associated with a first return spring 28. The actuator further includes a second armature 23, which in this embodiment is a part of the fuel pump 20a. Here, the second armature 23 is fixedly connected to a piston 26 of the fuel pump 20a. Alternatively, the second armature 23 and the piston 26 can only touch each other without a fixed connection. The second armature 23 is a cylindrical component and is guided inside the coil 21 by means of a guide element 19. The guide element 19 has, in addition to a guide function, also a support function for the first return spring 28. Reference numeral 29 denotes a non-magnetic element to interrupt the iron circle of the coil 21. The coil 21 actuates, when energized, both the first armature 22 and the second armature 23. After elimination of the energization of the coil 21 are the first

Return spring 28 and a second return spring 24 for the second armature the two anchors back to the initial positions shown in Figure 2 back. The second return spring is supported on a housing block 25a and an end face of the second armature 23.

As can be seen from Figure 2, the fuel supply line 6a and the housing 25 are on

Fuel return line 6b arranged. The fuel supply line 6a discharges into an intake space 30. The fuel return line 6b starts from a return space 32. The volume of Intake space 30 and the return space 32 are approximately equal. Alternatively, the suction space 30 and the return space 32 may also form a common space. In the housing block 25a, a pumping space 31 is further formed. The pumping space 31 is connected via a first bore 33 with the suction chamber 30 and via a second bore 34 with the return space 32. Here, no check valve is arranged between the suction chamber 30 and the pump chamber 32 above. The bore 33 thus forms a free connecting line between the pump chamber 31 and the suction chamber 30. Between the pump chamber 31 and the return chamber 32, a first check valve 35 is arranged. The pump chamber 31 is part of the fuel pump 20b. As can be seen from FIG. 2, the piston 26 of the fuel pump is arranged in the housing block 25a such that it can pressurize a fluid located in the pumping space 31. The piston 26 is firmly connected to the second armature 23. The position shown in Figure 2 is a position at the end of a suction stroke of the fuel pump 20a. The pump chamber 31, the first armature 22 and the second armature 23 lie on a common axis XX. As can be seen from FIG. 2, a pump space mouth of the second bore 34 in the axial direction XX of the injection module 2 is arranged at a position closer to the injector 20c than the pump space mouth of the first bore 33.

As further seen in Figure 2, the injector 20c includes a valve member 40 which is an outwardly opening valve member. The valve member 40 is disposed in a nozzle space 41 and includes a valve seat 40a and a spring holding portion 40b. A return spring 42 is disposed between the spring holding portion 40 b and a bottom portion 41 a of the nozzle space 41. The

Return spring always returns the valve member 40 to the starting position shown in Figure 2 and also provides a Öffhungsdruck with which the valve member 41 can be opened. A pressure in the nozzle chamber 41 acts via a pressure surface 40c of the valve member 40. A second check valve 36 is arranged in a connection between the pump chamber 31 and the nozzle chamber 41. The check valve 36 is supported by a spring against the pressure surface 40 c of the valve member 40 and opens when a pressure in the pump chamber 31 is higher than a pressure in the nozzle chamber 41. For holding the spring and the ball of the second check valve 36, a cage-like member is provided. The pressure regulator 20b is thus integrated in the injector 20c and comprises the return spring 42 and the spring holding portion 40b of the valve member 40, against which the return spring 42 is supported.

As further shown in FIG. 2, a connecting line 34 is arranged between the pumping space 31 and the return space 32 in the axial direction XX of the injection module 2 below the first connecting line 33. An installation position of the injection module 2 is selected such that a vertical direction coincides with the longitudinal direction XX of the injection module. The function of the injection module 2 according to the invention is as follows. An intake phase of the fuel pump 20a is introduced through the second return element 24, wherein the rest position of the second return element 24 defines the end of the intake phase. During the suction phase, the first check valve 35 and the second check valve 36 are closed. After a control edge 26a of the piston 26 during the return movement, ie, upward movement of the

Piston 26 has been moved behind the mouth of the first connecting line 33, fuel from the suction chamber 30 via the first connecting line 33 begins to flow into the pump chamber 31. The first and second check valves 35, 36 remain closed in each case. If there are gases in the pump chamber 31, they collect below the pressure surface at the control edge 26a of the piston 26. With the beginning of the pressure phase, the piston 26 in the direction of

Arrow A moves down when the coil 21 is energized. As a result, possibly existing gases are pushed out via the first connection line 33 back into the suction space 30 or the now open first check valve 35 into the return space 32. After passing over the mouth of the first connecting line 33 in the pump chamber 31 through the piston 26, the gases are pushed out only in the return space 32 via the open first check valve 35. Thus, the first part of the piston stroke is used for pushing out of any existing fuel vapors or other gases. Since the piston stroke for the degassing is relatively large, even large amounts of gas can be expelled from the pump chamber 31. After the piston 26, more precisely the control edge 26a of the piston, has crossed the connecting line 34, only the actual pressure build-up in the pressure chamber 31 begins. As soon as the pressure in the pressure chamber 31 becomes greater than a pressure in the nozzle chamber 41, the second check valve 36 opens that fuel can flow from the pumping space 31 into the nozzle space 41. If now the pressure in the nozzle chamber 41 is greater than a restoring force of the return spring 42, the valve member 40 opens to the outside, so that fuel can be injected into the suction pipe 8. When the pressure in the nozzle chamber 41 drops below the opening pressure again due to the injection, the return spring 42 closes the valve member 40 again. The energization of the coil 21 is stopped and the second return spring 24 reverses the direction of movement of the piston 26 again and the intake begins again as soon as the control edge 26a has crossed over the pump space mouth of the first connecting line 33. Since during the return stroke of the piston 26 in the first lifting part, a negative pressure in the pump chamber 31 is formed, guest regardless of temperature conditions, fuel vapor or air from the liquid fuel. Only after passing over the pump room mouth of the first connecting line 33 then begins the actual intake process. According to the invention, therefore, there are always large amounts of gas or vapor in the pumping space 31, so that any additional formation of vapor bubbles during a hot operating state does not lead to significant changes in the conveying behavior. This can ensure that always a constant amount of fuel can be injected into the intake manifold. When the fuel pump 20a is actuated, the first armature 22 of the air regulator 2Od is also attracted in the direction of the arrow B when the coil 21 is energized. As a result, the air actuator opens 2Od, so that air can flow through the bypass line 12. As a result, air can flow to the suction pipe 8 via the outlet 12z.

After injection, the energization of the coil 21 is terminated, so that the return springs 24 and 28, the first and second armature 22, 23 back to their original positions. As a result, the aerator 2Od is closed again and during the return of the second armature 23, the piston 26 is pulled back so that the suction phase begins again. It should be noted that the restoring forces of the return springs 24 and 28 are designed such that, with only a small current to the coil 21, the air actuator 2Od can also be operated separately without actuating the fuel pump.

Furthermore, the injection module 2 has a common actuator for the fuel pump 20a and the aerator 2Od. As a result, only one coil and a single electric power amplifier with wiring in the fuel pump 20a and the aerator 2Od is necessary. Furthermore, in the operating states of the small engine 1 in which it is required, ie usually idle, the aerator 2Od can open and close and in operating states in which it is not absolutely required, it can be ensured that despite the common actuator with the Fuel pump 20 a actuation of the fuel pump 20 a is not delayed or otherwise hindered. In the embodiment, a magnetic actuator by energizing a coil has been described as an actuator. It should be noted, however, that in principle other possible actuators may be used, e.g. a piezoactuator. It should also be noted that the described closure element 22a of the air actuator 2Od can also be designed as a tapering, in particular conical, end region of the armature 22, or in any other way, for example as a sphere or part sphere.

Hereinafter, an injection device 1 according to a second embodiment of the invention will be described in detail with reference to FIG. Identical or functionally identical parts are denoted by the same reference numerals as in the first embodiment.

The second embodiment substantially corresponds to the first embodiment, in contrast to the second embodiment, the injection module 2 has an annular space 50, which is a combined intake and return space. The annular space 50 is provided annularly around a housing block 25a, in which the pumping space 31 is arranged. Between the pumping chamber 31 and the annular space 50, a connecting line 51 is provided which connects the pumping space 31 with the annular space 50. The connecting line 51 comprises a common Stub 52, which emanates from the pumping space 31, and a branch 53. The branch 53 comprises a first line region 53a and a second line region 53b. The first line region 53a is arranged below the second line region 53b. The common stub 52 extends approximately from the center of the branch 53 (see Figure 3). In this case, the first line region 53a is opened toward the annular space 50 such that an opening of the first line region 53a lies at the level of a bottom region 50a of the annular space 50.

The annulus 50 is connected to a tank (not shown) via a fuel supply line 6a and a fuel return line 6b. In this case, an opening of the fuel return line 6b is arranged at a position on the tank, which is higher than a connection for the fuel supply line 6a. This ensures that fuel is supplied via the fuel supply line 6a to the annulus 50.

Furthermore, a connection to a spring chamber 55 is made via the second line region 53b, the second return spring 24 for the second armature 23 and the piston 26 being arranged in the spring chamber 55. In this way, an increase in volume of the annular space 50, which forms the common intake and return space, can be achieved, so that an actual volume of the annular space 50 can be dimensioned correspondingly smaller.

The function of the injection device according to the second embodiment is as follows. Figure 3 shows again the state of the injection module 2, in which a suction phase is completed. Now, when the coil 21 is energized, the piston 26 is moved (as indicated by the arrow A) down. Since an open connection is made between the pumping chamber 31 and the annular space 50 via the connecting line 51, any existing fuel vapors or other gases are expelled via the connecting line 51. In this case, the gases are ejected to the annular space 50 mainly via the second line region 53b, which is arranged above the common stub line 51. After exiting the second conduit portion 53b into the annulus 50, the gases will rise upward in the direction of the fuel return line 6b and returned to the tank. The arrangement of the branch 53 makes it possible that a certain chimney effect in the branch 53 is formed, whereby an increase of the gases in the second line region 53 b is favored. As long as the control edge 26b has not completely crossed over the common stub 52, there is still no pressure build-up in the pump chamber 31. This occurs only when the common stub 52 has been completely overrun by the piston 26. As soon as a pressure in the pumping chamber 31 is higher than a pressure in the nozzle chamber 41 of the injector 20c, the check valve 36 opens, which in a connection between the

Pumping chamber 31 and the nozzle chamber 41 is arranged, and the pressure in the nozzle chamber 41 increases. When the pressure in the nozzle chamber 41 has reached the opening pressure, the valve member 40 and opens Fuel is injected into the suction pipe 8. As soon as the pressure in the nozzle chamber 41 drops again below the opening pressure, the injector closes again and the energization of the coil is stopped, and the piston is returned to the starting position shown in FIG. During a first partial stroke of the feedback, no connection is yet established between the pump chamber 31 and the annular space 50 via the connecting line 51. This creates a negative pressure in the first intake phase in the pump chamber 31, so that there is an outgassing of the fuel in the pump chamber 31. Only when the control edge 26a of the piston 26 reaches the common stub 52, there is a suction of fuel via the connecting line 51. In this case, a suction takes place mainly via the first line region 53a. Since the first line region 53a opens at the lowest point of the annular space 50, it can be ensured that only liquid fuel is sucked in via the first line region 53. As a result, a minimum amount of liquid fuel is sucked into the pump chamber 31.

As bubbles rise in a liquid, ejecting gases from the pumping space 31 ejects more bubbles than can be sucked in again during suction. This ensures that a sufficient filling of the pump chamber 31 with liquid fuel is always achieved.

In the second embodiment, an injection module is achieved, which requires neither a check valve between the pump chamber and the suction chamber nor a check valve between the pump chamber and return chamber. Since in this embodiment a common

Intake-return space is provided, this injection module can be designed to be particularly compact and physically small. Furthermore, in particular a number of moving parts can be minimized, so that this injection module is particularly robust and durable.

Otherwise, this embodiment corresponds to the previous embodiment, so that reference can be made to the description given there.

Claims

claims

An injection apparatus comprising a fuel pump (20a), a pressure regulator (20b), an injector (20c) and an aerator (20d), characterized in that the fuel pump (20a), the injector (20c) and the aerator (20d) are an integral part of an injection module (2), the pressure regulator (20b) is an integral part of the injector (20c), and the fuel pump (20a) comprises a pumping space (31) and the injection module (2) comprises a suction space (30; the suction space (30; 50) is connected to the pump space (31) via a free connection line (33; 51).

2. Injection device according to claim 1, characterized in that a total stroke of a piston (26) of the fuel pump (20a) comprises a Ausschiebeteilhub and a Druckzeugungsteilhub and the Ausschiebeteilhub is equal to or greater than the Druckzeugungsteilhub.

3. Injection device according to claim 1 or 2, characterized in that between the pump chamber (31) and a return space (32), a first check valve (35) is arranged.

4. Injection device according to claim 3, characterized in that in the axial direction (XX) of the injection module (2) a pump space mouth of a connecting line (34) between the pump chamber (31) and the return space (32) is arranged closer to the injector, as a Pump chamber mouth of the free connection line (33) between the suction chamber (30) and the pump chamber (31).

5. Injection device according to claim 1 or 2, comprising an annular space (50) in which a power supply line (6a) and a fuel return line (6b) open and a connecting line (51) which connects the annular space (50) with the pump chamber (31) wherein the connecting line (51) comprises a common stub line (52) to the pumping space (31) and a branch (53) to the annular space (50) with a first line area (53a) and a second line area (53b), wherein the first line area (53) 53a) opens below the second line region (53b) in the annular space (50).

6. Injection device according to claim 5, characterized in that a spring chamber (55), in which a return spring (24) for the armature (23) of the piston (26) is arranged, with the annular space (50) is connected.

7. Injection device according to claim 5 or 6, characterized in that the first line region (53a) of the branch (53) at the level of a bottom region (50a) of the annular space (50) opens.

8. Injection device according to one of claims 5 to 7, characterized in that the common stub (52) in the middle of the branch (53) between the first and second conduit region (53a, 53b) is arranged.

9. Injection device according to one of the preceding claims, characterized in that the pump chamber (31) in a central housing block (25 a) is arranged.

10. Injection device according to one of the preceding claims, characterized in that the injection device comprises exactly one actuator which actuates both the fuel pump (20a) and the air actuator (2Od), wherein the actuator comprises a coil (21), a first armature (22 ) and a second anchor (23).

11. Internal combustion engine comprising exactly one or exactly two cylinders and an injection device according to one of the preceding claims.