EP2240682B1 - Compact injection device with a pressure-controlled nozzle - Google Patents

Description

State of the art

The present invention relates to an injection device with a fuel pump, a pressure regulator, a nozzle with a pressure-controlled nozzle and an air actuator, as in US 5170761 presented, but 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. Applications of such small internal combustion engines are, for example, two-wheelers or tricycles or lawn mowers, etc. Known injection devices usually comprise in a tank a fuel pump with a pressure regulator, wherein the fuel pump fuel at a predetermined pressure in a line, e.g. a rail or similar, 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 the EP 1 340 906 B1 or EP 1 306 544 A1 For example, an electronic control fuel injection device is known in which an injector is disposed near 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.

Injectors with membranes in the pressure-controlled nozzles are made of eg DE 4445585 . DE 4202387 or WO 03/078826 known.

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 become. As a result, the injection device according to the invention can be used in particular in small internal combustion engines, for example in two-wheeled vehicles or lawnmowers or the like. This is inventively achieved in that the injection device comprises a fuel pump, a pressure regulator for controlling an injection pressure, an injector with pressure-controlled nozzle and an air actuator, which are integral components of an injection module. The injection module is a compact, small-sized component, in which the fuel pump, the pressure regulator, the injector and the air actuator are arranged. Since the injector comprises a pressure-controlled nozzle, the injector can be provided in a particularly simple and cost-effective manner. The pressure-controlled nozzle comprises a pressure chamber, a nozzle body and an elastic membrane. According to the invention, the term elastic membrane is understood to mean an elastic component which provides a predetermined deformation at a pressure increase in the pressure chamber, in order to enable an injection of fuel from a predetermined pressure level in the pressure chamber. Due to the pressure-controlled nozzle, the injection device thus has a very simple and inexpensive construction. 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. As a result, the injection device according to the invention is particularly suitable for use in small machines.

The dependent claims show preferred developments of the invention.

The injector preferably comprises an 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.

Preferably, the nozzle body of the injector comprises a sealing seat. The membrane rests against the sealing seat and the membrane has at least one injection opening. Thus, the membrane also has the effect of a closing member for the injector, wherein the membrane lifts from the sealing seat when the pressure in the pressure chamber has risen above the predetermined pressure, so that fuel through the gap between the sealing seat and the Membrane can flow and can be ejected from the injection port of the membrane. As a result, the number of parts of the pressure-controlled nozzle can be kept very low.

According to a further preferred embodiment of the present invention, the pressure-controlled nozzle comprises a closing body which is arranged on a side of the membrane facing the pressure chamber on the membrane. Thereby, the membrane is given an improved stability, so that in particular a tearing of the membrane during operation can be avoided. The pressure-controlled nozzle thus has a longer life. The closing body can be attached to the membrane, for example, by gluing or welding. In order to have the simplest possible construction, the sealing seat on the nozzle body is preferably annular. This also has fluidic advantages during the injection process.

More preferably, the membrane is fixed directly on the nozzle body. The membrane is preferably fixed to the nozzle body by means of laser welding, wherein the nozzle body is preferably cylindrical at the region in which the membrane is to be fastened. This makes it possible for the membrane to have a structure similar to a hemisphere or shell.

According to a preferred alternative of the present invention, the nozzle body of the pressure-controlled nozzle comprises a sealing seat and the membrane is connected to a closing body. The closing body cooperates with the sealing seat and releases or closes a gap between closing body and sealing seat for injection of fuel. By providing the closing body on the membrane, a long service life of the pressure-controlled nozzle can likewise be ensured. The closing body is preferably a ball, wherein the membrane is fixed to the maximum circumference of the ball.

According to a further preferred embodiment of the present invention, the pressure-controlled nozzle preferably comprises a return element to return the membrane to its original position. As a result, a provision of the membrane can be made faster, and the membrane can be made of a low-cost, flexible material.

More preferably, a stop is provided to limit a stroke of the membrane. This ensures that the diaphragm is not damaged due to a too large stroke.

According to a further preferred embodiment of the invention, the membrane is connected to a sealing ring. The sealing ring is arranged with radial clearance in an annular groove, wherein the annular groove is formed in the nozzle body. As a result, the membrane has a radial play on the sealing ring, so that they can center together with a closing body in the sealing seat. The sealing ring is preferably an O-ring.

More preferably, the membrane comprises at least one or more concentric waves. Due to the concentric waves, the membrane has a softer behavior.

Preferably, the fuel pump comprises a pumping chamber and further a first, a second and a third check valve, which are arranged on supply lines or outlets of the pumping chamber. Here, the first check valve between a supply area for fuels and the pumping chamber is arranged. The second check valve is disposed between the pumping chamber and the injector, and the third check valve is disposed between the pumping chamber and a discharge area of overpressure peaks. The use of the pumping chamber allows a particularly compact and thus space-saving and inexpensive construction and can preferably be arranged on a common axis with the armature of the actuator. The pumping chamber preferably has a volume which corresponds to a volume of a maximum injectable amount of fuel at maximum injection pressure.

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

drawing

Figur 1

eine schematische Ansicht eines Kleinmotors mit einer Einspritzvorrichtung gemäß einem ersten Ausführungsbeispiel der Erfindung,

Figur 2

eine schematische Ansicht der Einspritzvorrichtung gemäß dem ersten Ausführungsbeispiel,

Figur 3

eine schematische Schnittansicht einer druckgesteuerten Düse gemäß dem ersten Ausführungsbeispiel,

Figur 4

eine schematische Schnittansicht einer druckgesteuerten Düse gemäß einem zweiten Ausführungsbeispiel der Erfindung,

Figur 5

eine schematische Schnittansicht einer druckgesteuerten Düse gemäß einem dritten Ausführungsbeispiel der vorliegenden Erfindung,

Figur 6

eine schematische Schnittansicht einer druckgesteuerten Düse gemäß einem vierten Ausführungsbeispiel der vorliegenden Erfindung,

Figur 7

eine schematische Schnittansicht einer druckgesteuerten Düse gemäß einem fünften Ausführungsbeispiel der vorliegenden Erfindung,

Figur 8

eine schematische Schnittansicht einer druckgesteuerten Düse gemäß einem sechsten Ausführungsbeispiel der vorliegenden Erfindung, und

Figur 9

eine schematische Schnittansicht einer druckgesteuerten Düse gemäß einem siebten Ausführungsbeispiel der vorliegenden Erfindung.

Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings. In the drawing is:

FIG. 1

a schematic view of a small motor with an injection device according to a first embodiment of the invention,

FIG. 2

a schematic view of the injection device according to the first embodiment,

FIG. 3

a schematic sectional view of a pressure-controlled nozzle according to the first embodiment,

FIG. 4

a schematic sectional view of a pressure-controlled nozzle according to a second embodiment of the invention,

FIG. 5

a schematic sectional view of a pressure-controlled nozzle according to a third embodiment of the present invention,

FIG. 6

FIG. 2 a schematic sectional view of a pressure-controlled nozzle according to a fourth exemplary embodiment of the present invention, FIG.

FIG. 7

FIG. 2 a schematic sectional view of a pressure-controlled nozzle according to a fifth exemplary embodiment of the present invention, FIG.

FIG. 8

a schematic sectional view of a pressure-controlled nozzle according to a sixth embodiment of the present invention, and

FIG. 9

a schematic sectional view of a pressure-controlled nozzle according to a seventh embodiment of the present invention.

Preferred embodiments of the invention

The following is with reference to the FIGS. 1 to 3 a small motor 1 with an injection device according to the invention according to a first embodiment described in detail.

FIG. 1 schematically shows 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 out FIG. 1 schematically, 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, a pressure regulator, an injector 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 of the bypass line 12 lies directly adjacent to the injector of the injection module. 2

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 comprising a cooling water sensor 15, an oil temperature sensor 16 and a sensor unit 17 for detecting a throttle position, a temperature in the intake manifold 8 and a Pressure in the suction pipe 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 air actuator 20d are integrated. For this purpose, a multi-part housing 25 is provided. A common actuator simultaneously actuates the fuel pump 20a and the air actuator 20d. The common actuator comprises a coil 21 and an armature 22 FIG. 2 it can be seen, a closing member 23 of the air actuator 20d is attached to the armature 22, wherein the closing member 23 can release or close the bypass line 12 to a valve seat 12a of a bypass line 12. The armature 22 is also fixedly connected to a piston 24, which in this embodiment is a part of the fuel pump 20a. The piston 24 is designed as a plunger. The coil 21 actuates when energized, both simultaneously the closing member 23 and the piston 24. After elimination of the energization of the coil 21, a return spring 28, the closing member and the piston 24 back into the in FIG. 2 back home positions shown. In the FIG. 2 shown position is a position at the end of a suction stroke of the fuel pump 20a.

The injection module 2 further comprises the multi-part housing 25, comprising a first housing part 25a, a second housing part 25b, a third housing part 25c and a fourth housing part 25d. The first housing part 25a is assigned to the air actuator 20d and provides the valve seat 12a of the air actuator 20d ready. Furthermore, the first housing part 25a still has the function of a guide element for the armature 22. The second housing part 25b covers the coil 21 from. The third housing part 25c serves to receive the coil 21 and the fourth housing part 25d serves as a guide element for the piston 24 and provides a pumping chamber 27 ready. In the fourth housing part 25d connections are also arranged for the fuel supply line 6a and 6b for a fuel return line. The fuel supply line 6a opens into the pumping chamber 27 and the fuel return line 6b starts from the pumping chamber 27. It should be noted that it is also possible that the fuel return line 6b does not lead back into a tank, but is connected to the fuel supply line 6a. In the fourth housing part 25d, a first check valve 29, a second check valve 30 according to the invention and a third check valve 31 are arranged. The first check valve 29 is disposed between the fuel supply line 6 a and the pumping chamber 27. The second check valve 30 according to the invention is arranged between pumping chamber 27 and a pressure chamber 41 of a pressure-controlled nozzle 40. The third check valve is disposed between the pump chamber 27 and the fuel return line 6b. The third check valve 31 in this case forms the pressure regulator 20b in order to reduce an overpressure possibly arising in the third pumping chamber 27. The second check valve 30 according to the invention is further designed such that it opens from a predetermined pressure in the pumping chamber 27, so that fuel can flow into the pressure chamber 41.

As in particular from the Figures 2 and 3 it can be seen, the injector 20c in addition to the second check valve 30 according to the invention also includes a pressure-controlled nozzle 40. The pressure-controlled nozzle 40 is in detail in FIG. 3 shown. The pressure-controlled nozzle 40 comprises a nozzle body 44, in which an inlet bore 45 is arranged. The inlet bore 45 provides a connection between the second check valve 30 and the pressure chamber 41 ready. The pressure chamber 41 is arranged annularly at the end of the pressure-controlled nozzle 40. On the nozzle body 44, a sealing seat 46 is also still formed, which is formed in this embodiment as a ring. Furthermore, the pressure-controlled nozzle 40 comprises a membrane 42 according to the invention, in which a plurality of spray holes 43 are formed. The membrane 42 according to the invention is attached to the nozzle body 44 by means of laser welding. How out FIG. 3 can be seen, the membrane 42 in the attached state has a hemispherical or shell-like shape. In this case, the inside of the membrane 42 abuts against the sealing seat 46. As a result, an injection chamber 47 is formed between the membrane 42 and the inner region on the sealing seat 46.

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 return element 28, wherein the rest position of the return element 28 defines the end of the intake phase. During the suction phase, the first check valve 29 is opened and the second and third check valves 30, 31 are each closed. As a result, fuel can flow into the pumping chamber 27 via the open first check valve 29. The coil 21 is then energized so that the armature 22 is moved in the direction of the arrow A in order to pressurize the fluid in the pumping chamber 27 by means of the piston 24. This closes the first check valve 29 and as long as there is still a low pressure level in the pumping chamber 27, the second and the third check valve 30, 31 also remain closed. From a predetermined pressure level then opens the second check valve 30 so that pressurized fluid can flow into the injector 20 c and flows through the inlet bore 45 into the pressure chamber 41. Since the membrane 42 is made of an elastic material, as soon as the pressure in the pressure chamber 41 exceeds a predetermined pressure level, the membrane 42 is deformed, so that the membrane 42 lifts off from the sealing seat 46. This is in FIG. 3 represented by the dashed membrane 42 '. As a result, fuel can be injected into the suction pipe 8 via the injection holes 43. FIG. 3 schematically shows a spray 48, which is ejected from the spray holes 43. Should a pressure in the pumping chamber 27 become too great, ie greater than a reference value, the third check valve 31 opens in order to reduce such pressure peaks into the fuel return line. Thus, the third check valve 31 takes over the function of the pressure regulator 20b. Simultaneously with the actuation of the fuel pump 20a, the closing member 23 of the air actuator 20d is lifted from the seat 12a during energization of the coil 21. As a result, the air actuator 20d opens, so that air can flow through the bypass line 12.

When the injection is to be terminated, the energization of the coil 21 is terminated, so that the armature 22 by the return element 28 back into the in FIG. 2 shown initial position is reset. In this case, the piston 24 is pulled out of the pumping chamber 27, so that a pressure level in the pumping chamber 27 is reduced. This closes the second check valve 30, so that the pressure in the pressure chamber 41 is reduced. As a result, the membrane 42 can automatically return to its original position and bears against the annular sealing seat 46. This completes the injection. By the return movement of the piston 24 also begins again the intake phase in which the first check valve 29 is opened and fuel is sucked in via the fuel supply line 6a. In order to prevent contamination in particular of the check valves and the pressure-controlled nozzle, a filter 33 is further in the Fuel supply arranged. At the same time, the return of the armature 22 and the air plate 20d closed again

Due to the pressure-controlled nozzle 40, the injector 20c thus has a very simple and low-wear construction. The injection of fuel via a pressure control, so that no expensive electronic control o.ä. necessary is. The injection can be realized simply by energizing or not energizing the armature. As a result, in particular expensive, outwardly opening nozzles can be dispensed with.

Thus, according to the invention, the injection module 2 has a common actuator for the fuel pump 20a and the aerator 20d. As a result, only one coil and a single electric power amplifier with wiring in the fuel pump 20a and the air actuator 20d is necessary. Furthermore, the air actuator 20 d in the operating conditions of the small engine 1, in which it is needed, ie, usually idle, open and close and in operating conditions in which it is not mandatory, 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.

It should be noted that the injection device is very compact and inexpensive, and the injection module 2 comprises in each case as integral components a fuel pump 20a, a pressure regulator 20b, a pressure-controlled nozzle injector 20c and an aerator 20d. In this case, a common actuator for the air actuator 20d and the fuel pump 20a with an armature 22 is provided in particular. In the embodiment, in each case a magnetic actuator was described by energizing a coil as an actuator. It should be noted, however, that in principle other possible actuators may be used, e.g. a piezoactuator.

The following is with reference to FIG. 4 an injection device according to a second embodiment of the invention described in detail. Equal or functionally identical parts are denoted by the same reference numerals as in the first embodiment. The injection device of the second embodiment has the difference from the first embodiment, only a modified pressure-controlled nozzle 40. How out FIG. 4 it can be seen, a closing body 49 is arranged on an inner side of the membrane 42. The closing body 49 is firmly connected to the membrane 42, for example by gluing. The closing body 49 closes a connection between the pressure chamber 41 and the injection chamber 42 at a sealing seat 46. The sealing seat 46 is again annular and formed on the nozzle body 44. The sealing seat is formed by an annular flat surface, which is in contact with the closing body 49 to the connection between the Pressure chamber 41 and the Abspritzraum 47 to close. If, as described in the first embodiment, a pressure increase takes place in the pressure chamber 41, a deformation of the membrane 42 is carried out from a predetermined pressure, so that the closing body 49 lifts from the sealing seat 46. As a result, a connection between the pressure chamber 41 and the spray chamber 47 is opened, so that fuel can be injected via the spray holes 43 into the suction pipe 8. A provision of the membrane 42 is carried out as in the first embodiment by a pressure reduction in the pressure chamber 41. As from FIG. 4 it can be seen, the membrane 42 of the second embodiment is further formed flat, so that the membrane can be fixed in particular free of stress on the nozzle body 44. Otherwise, this embodiment corresponds to the first embodiment, so that reference can be made to the description given there.

FIG. 5 shows a pressure-controlled nozzle 40 according to a third embodiment of an injection device of the invention. The pressure-controlled nozzle 40 of the third embodiment substantially corresponds to that of the second embodiment, in contrast to the sealing seat 46 is formed on the nozzle body by a tapered, in particular conical, region 46a. In a corresponding manner, a sealing surface 49a in the form of a cone is formed on the closing body 49. Otherwise, this embodiment corresponds to the second embodiment, so that reference can be made to the description given there.

FIG. 6 shows an injection device with a pressure-controlled nozzle 40 according to a fourth embodiment of the present invention. Equal or functionally identical parts are denoted by the same reference numerals as in the preceding embodiments.

In contrast to the previous exemplary embodiments, the pressure-controlled nozzle 40 of the fourth exemplary embodiment additionally comprises a valve body 50. The sealing seat 46 has a conical shape and has a passage opening 46a at an upper end of the cone, which can be closed by means of a membrane 42. At the back of the membrane 42, a spring 51 is further arranged, which is supported against the valve body 50. Next, a stroke stop 52 is formed on the valve body 50. The function of the pressure-controlled nozzle of the fourth embodiment is as follows. As soon as an increase in pressure takes place in the pressure chamber 41, the diaphragm 42 is lifted against the spring force of the spring 51 from the sealing seat 46. As a result, fuel can reach the spray chamber 47 and be sprayed from there through spray holes 43, which are arranged in a perforated disk 53. The stroke stop 52 limits a path of the membrane 42. As soon as the pressure in the pressure chamber 41 is reduced again, as described above, the spring 51, the membrane 42 back to the starting position. As a result, the membrane 42 is again against the sealing seat 46 and the injection is completed. The nozzle body 44 and the valve body 50 can be connected, for example by welding.

The following is with reference to FIG. 7 an injection device with a pressure-controlled nozzle according to a fifth embodiment of the invention described in detail. Identical or functionally identical parts are again denoted by the same reference numerals as in the previous embodiments.

How out FIG. 7 can be seen, the pressure-controlled nozzle 40 of the fifth embodiment, in contrast to the previous embodiments, a membrane 42 which is fixedly connected to a designed as a ball closure member 49. The membrane 42 has a circular hole in which a partial section of the ball is arranged. The closing body 49 is attached to the membrane 42 by means of gluing or laser welding. The membrane 42 itself is fixed to a nozzle body 44 by means of laser welding. The closing body 49 rests against a sealing seat 46 formed on the nozzle body 44 in the closed state. Subordinate to the sealing seat 46 in the flow direction is a bore opening 56, which is covered with a perforated disc 53. In the perforated disc 53 a plurality of injection holes 43 are provided, from which a spray 48 emerges when the nozzle is open. When the pressure-controlled nozzle 40 is supplied with pressurized fuel via the inlet bore 45 into the pressure chamber 41, begins from a predetermined pressure level, a deformation of the membrane 42, wherein at the same time the closing body 49 lifts from the sealing seat 46. In FIG. 7 the deformed membrane is designated by the reference numeral 42 'and the lifted closing body 49 by the reference numeral 49'. Thereby, a connection between the pressure chamber 41 and the bore opening 56 is released, so that fuel can flow through the injection holes 43 to the outside. As soon as the pressure in the pressure chamber 41 drops again, the membrane 42 returns itself to its original position due to its inherent elasticity, with the closing body 49 once again resting against the sealing seat 46 and closing it. This completes the injection. The provision of the perforated disc 53 also has the advantage that the pressure-controlled nozzle may have a basic structure for various purposes, whereby by simply replacing the perforated disc 53 different sprays for different purposes can be generated. As a result, the production costs for the pressure-controlled nozzle can be kept very low. Otherwise, this embodiment corresponds to the previous embodiments, so that reference can be made to the description given there.

The following is with reference to FIG. 8 a pressure-controlled nozzle 40 according to a sixth embodiment of the invention described in detail. Equal or functionally identical parts are denoted by the same reference numerals as in the previous embodiments.

The pressure-controlled nozzle 40 of the sixth embodiment corresponds to the essential of the Fifth embodiment, the difference in addition, in addition, a return spring 51 and a stroke 52 are provided. The stroke stop 52 limits an opening degree of the nozzle, since at a pressure increase of the closing body 49 abuts against the stroke stop 52 and thus another open at the sealing seat 46 is no longer possible. By providing the return spring 51, the membrane 42 can also be provided very inexpensively, since the membrane 42 does not have to apply its own restoring forces and thus can be made of a cost-effective material. The stroke stop 52 is attached to an additional part 44 a of the nozzle body 44. A space 54, in which the stroke stop 52 and the return spring 51 are arranged, is filled with a compressible medium, preferably air. Otherwise, this embodiment corresponds to the previous embodiments, so that reference may be made to the description given there.

Further, the diaphragm 42 includes two concentric shafts 42a concentrically disposed about a center of the diaphragm. By providing concentric shafts 42a, the membrane softens and can thereby provide a faster response to pressure changes.

The following is with reference to FIG. 9 a pressure-controlled nozzle according to a seventh embodiment of the invention described in detail. Equal or functionally identical parts are denoted by the same reference numerals as in the preceding embodiments.

How out FIG. 9 can be seen, the seventh embodiment substantially corresponds to the sixth embodiment. In contrast to the sixth embodiment, however, the attachment of the membrane 42 on the nozzle body 44 is configured differently in the seventh embodiment. How out FIG. 9 can be seen, the membrane 42 is connected to an O-ring 55 at its outer periphery. The O-ring 55 is disposed in an annular groove 44b in the nozzle body 44. How out FIG. 9 it can be seen, the O-ring 55 has a lateral radial clearance S 1 inwards and a lateral radial clearance S2 outwards. This has the advantage that the membrane 42 and thereby also the closing body 49, which is firmly connected to the membrane 42, can center itself. As a result, the tolerance requirements for the items are slightly lower, so that a more cost-effective production is possible. Otherwise, this embodiment corresponds to the previous embodiment, so that reference can be made to the description given there.

Claims (12)

1. Injection apparatus, comprising a fuel pump (20a), a pressure regulator (20b), an injector (20c) and a pneumatic actuator (20d), characterized in that the fuel pump (20a), the pressure regulator (20b), the injector (20c) and the pneumatic actuator (20d) are an integral constituent part of an injection module (2), and the injector (20c) comprises a non-return valve (30) and a pressure-controlled nozzle (40) with a pressure space (41), a nozzle body (44) and a diaphragm (42), the non-return valve (30) being arranged between a pump chamber (27) of the fuel pump (20a) and the pressure space (41) of the pressure-controlled nozzle (40) and being designed in such a way that the said non-return valve (30) opens above a predefined pressure in the pump chamber (27), with the result that fuel can flow into the pressure space (41).
2. Injection apparatus according to Claim 1, characterized in that the nozzle body (44) comprises a sealing seat (46), against which the diaphragm (42) bears, and the diaphragm (42) has at least one spray orifice (43), an injection space (47) being arranged between the diaphragm (42) and the nozzle body (44), and the at least one spray orifice (43) of the diaphragm (42) being arranged in the region of the ejection space (47).
3. Injection apparatus according to Claim 2, further comprising a closing body (49) which is arranged on a side of the diaphragm (42), which side is directed towards the pressure space (41).
4. Injection apparatus according to Claim 2 or 3, characterized in that the sealing seat (46) is of annular configuration.
5. Injection apparatus according to one of the preceding claims, characterized in that the diaphragm (42) is fixed on the nozzle body (44).
6. Injection apparatus according to Claim 1, characterized in that the diaphragm (42) is connected to a closing body (49), and the closing body (49) bears against a sealing seat (46) which is formed on the nozzle body (44).
7. Injection apparatus according to one of the preceding claims, further comprising a restoring element (51), in order to reset the diaphragm (42) into a starting position.
8. Injection apparatus according to one of Claims 1 to 6, characterized in that the diaphragm (42) has an inherent elasticity, in order to be reset automatically into a starting position.
9. Injection apparatus according to one of the preceding claims, further comprising a stop (52), in order to limit a stroke during an injection operation.
10. Injection apparatus according to one of Claims 6 to 9, characterized in that the diaphragm (42) is connected to a sealing ring (55), the sealing ring (55) being arranged with a radial play in an annular groove (44b) of the nozzle body (44), in order to make self-centring of the diaphragm (42) possible.
11. Injection apparatus according to one of the preceding claims, characterized in that the diaphragm (42) has at least one concentric undulation.
12. Internal combustion engine, comprising precisely one or precisely two cylinders and an injection apparatus according to one of the preceding claims.

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