TWI484094B - Kompakte einspritzvorrichtung mit flachanker-luftsteller - Google Patents

Description

Compact fuel injection device with flat anchor air conditioner

The present invention relates to a compact fuel injection device having an oil pump, a pressure regulator, a fuel injector, and an air conditioner.

There are a variety of conventional fuel injection devices of different designs in the prior art. A small internal combustion engine with only one or two cylinders and a small cylinder capacity requires a separate solution for cost and installation space reasons. For example, the field of application of such small internal combustion engines is a two-wheeled vehicle, a tricycle or a lawn mower. Conventional fuel injection devices typically include an oil pump located within the fuel tank and having a pressure regulator, wherein the oil pump inputs fuel into a line (e.g., a rail) at a predetermined pressure. An injector is arranged at the end of the pipeline, and the injector sprays fuel into the suction pipe or directly into the combustion chamber under the control of the control device. However, such fuel injection devices are extremely complicated and particularly expensive, and thus the cost of small internal combustion engines is extremely high.

EP 1 340 906 B1 discloses an injection device with an electronic control unit, the injector of which is arranged close to the pump piston. In addition, an initial pressure valve is provided in the return line of the fuel returning to the tank for applying an initial pressure to the fuel during the initial stage of the pump piston compression stroke. During this process, the initial pressure valve discharges a portion of the fuel in the pressure chamber into the return line. The purpose of this measure is primarily to reduce bubble formation in the injector. However, the structure of the fuel injection device is quite complicated and requires a large installation space.

In contrast, the fuel injection device of the present invention having the features of claim 1 has the advantage of being extremely compact. In addition, the fuel injection device of the present invention is easy to manufacture, And the cost is low. According to the invention, the fuel injection device comprises an oil pump, a pressure regulator for adjusting the injection pressure, a fuel injector and an air regulator, and the components are a bulk component of a fuel injection module. The fuel injection module is a small compact assembly. Among them, the pressure regulator is a bulk component of the injector. In addition to the fuel injection module, the fuel injection device of the present invention also includes a fuel supply pipe, a return oil pipe and an air bypass pipe. The oil pump includes a pump piston, a pump anchor, and a pump chamber in which pressure can be applied to the fuel. The air regulator includes a valve seat and a flat anchor. Wherein, the pump anchor and the flat anchor can be manipulated by a common coil, so that the air conditioner and the oil pump can be provided with a common actuator by only one electrical connector. The fuel injection module can be fully pre-assembled by simply connecting it to the necessary connections and then directly into the vehicle. The components of the fuel injection module are preferably disposed within a common housing of the fuel injection module. In addition to the tightness of the fuel injection module, the fuel injection device also has the advantage of minimizing other components for the fuel injection module.

Preferred refinements of the invention are given by the respective sub-items.

According to a particularly good design, the pump anchor of the oil pump is annular, and the return flow of fuel from the fuel injection module back to the fuel tank passes through the annular pump anchor. In this way, the fuel injection module has a particularly tight structure, and in addition, the heat of the fuel injection module can be discharged into the fuel tank by the backflow of the fuel through the pump anchor. The flow of the pump anchor can be achieved with only a small pressure loss. According to a further preferred refinement, the annular pump anchor is arranged substantially vertically, in which case bubbles which may be present in the fuel can pass through the pump anchor during the ascent and into the tank. When the fuel passes through the pump anchor, it is heated by the waste heat of the electromagnetic coil absorbed by the pump, thereby further enhancing the degassing effect on the heated fuel. This fuel cycle is also ensured Always flowing cold fuel to the fuel injection module.

According to another preferred embodiment, the flat anchor of the air conditioner is designed to be annular. Thereby, it is ensured that the magnetic lines of force enter and exit the flat anchor in the axial direction. In addition, the annular flat anchors also allow fuel to be centered through the fuel injection module inside the flat anchor. The air conditioner preferably has three through holes that are partially annular or kidney shaped. Sealing faces are formed on the edges of the through holes, either in the form of two concentric annular sealing faces, or by projections provided along the circumference of each through hole. With the arrangement of the sealing faces, a large area can be opened with only a small displacement, that is, a larger air volume can be provided with only a small opening stroke.

According to a particularly preferred design, the fuel return path also passes through the annular flat anchor. Thereby, the heat which may be generated in the annular flat anchor can be discharged, so that the fuel injection module has a particularly compact structure.

According to another preferred embodiment of the present invention, the flat anchor is fixed to the outer casing of the fuel injection module by a return spring. The return spring is preferably an annular disc spring that secures the flat anchor to the outer casing.

From the axial direction of the pump piston, the connecting passage between the pump chamber and the suction chamber is preferably arranged below the dead point of the upper side of the pump piston. In this case, when the pressure recovery phase of the oil pump starts, the pressure in the pump chamber cannot be immediately restored, but the gas that may be present is discharged from the pump chamber into the suction chamber by the connecting passage. In addition, the pump piston can be quickly accelerated to its target speed because at the beginning of the pressure recovery phase, there is only a small hydraulic reaction force generated by the fuel. After the connecting passage is closed by the pump piston, the pump chamber begins the true pressure recovery phase.

In order to minimize the structure and reduce the cost, the connecting passage between the pump chamber and the suction chamber is preferably arranged in the annular passage region below the suction chamber. According to another preferred embodiment, a filter element is arranged between the annular passage region below the suction chamber and the main zone. This ensures that only the amount of fuel in the suction pump chamber is filtered, without the need to filter the total fuel quantity entering the suction chamber. That is, the fuel that participates in the cycle is not filtered, thereby extending the life of the filter.

According to an alternative embodiment of the invention, the pump piston has a recess which extends over the outer circumference of the pump piston to the pressure surface of the pump piston which is oriented toward the pump chamber. The gap establishes a connection between the pump chamber and the suction chamber at the beginning of the pressure recovery phase of the oil pump, which is released after the pump piston has moved a certain distance. The gap is preferably a longitudinal groove in the pump piston whereby fluidization of the slot can be achieved during pressure recovery in the pump chamber.

According to another preferred embodiment, the casing of the fuel injection module is provided with a sleeve for the pump piston, which is integral with the outer casing. Thereby, the structure of the fuel injection device can be further simplified, and the cost of the fuel injection device can be further reduced. For example, the sleeve can be a cylinder liner.

The invention further relates to an internal combustion engine which accurately comprises one or two cylinders and a fuel injection device of the invention. According to a particularly preferred design, the internal combustion engine includes a fuel tank disposed above the fuel injection module. This can significantly reduce the design size of the oil pump.

Next, a small electric motor 1 having a fuel injection device using an embodiment of the present invention will be described in detail with reference to Figs.

Fig. 1 shows a structural view of a small motor 1 designed as a single cylinder machine. The small motor 1 includes a cylinder 3, a pump piston 4 that can reciprocate within the cylinder, a control unit 5, and a fuel tank 6. The oil tank 6 is connected to the fuel injection module 2 via the oil supply pipe 6a. The oil return pipe 6b extends from the fuel injection module 2 to the oil tank 6. As shown in FIG. 1, the oil tank 6 is disposed above the fuel injection module 2. Therefore, the fuel flows to the fuel injection module 2 along the oil supply pipe 6a under the action of gravity. The fuel injection module 2 is extremely simple in illustration, and includes an oil pump, an injector with an integrated pressure regulator, and an air conditioner. Therefore, the fuel injection module 2 has an extremely compact structure.

The small electric motor 1 furthermore comprises a throttle valve 7 arranged in the oil suction pipe 8. A spark plug 9, an inlet valve 10, and a discharge valve 11 are disposed on the cylinder 3. The component symbol 12 is an air bypass pipe that divides the air in the area in front of the throttle valve with the suction pipe 8 in the air flow direction, and directs the portion of the air directly into the fuel injection module 2 . Air conditioner in the middle. The outlet 12z of the bypass pipe 12 communicates with the oil suction pipe 8 behind the throttle valve 7.

The small electric motor 1 furthermore comprises an exhaust pipe 13 which is responsible for the opening and closing of the exhaust pipe. An oxygen sensor 14 is disposed on the exhaust pipe 13 , and the oxygen sensor is connected to the control unit 5 , and the control unit 5 is further connected to the cooling water sensor 15 , the oil temperature sensor 16 and the sensing unit 17 . The sensing unit is used to sense the position of the throttle valve, the temperature and pressure within the oil suction pipe 8. The control unit 5 controls the fuel injection module 2 according to the received signal.

That is, the fuel injection device of the present invention includes a fuel injection module 2, a fuel supply pipe, a return oil pipe and an air bypass joint, wherein the fuel injection module 2 has an oil pump, a pressure regulator, a fuel injector and an air regulator. Therefore, the fuel injection device can be designed in a particularly compact and small volume. In addition, the fuel injection device of the present invention is extremely expensive It can be pre-installed as a complete fuel injection module in advance, so it is only necessary to install it as a compact module into the small motor 1. By integrating four components, such as an oil pump, a pressure regulator, a fuel injector, and an air conditioner, into the fuel injection module, manufacturing can be simplified and costs can be reduced. Among them, the oil pump and the air conditioner are operated by a common actuator. Thereby, the fuel injection device 2 of the present invention can be applied to a small motor of a two-wheeled vehicle or a lawn mower.

2 is a detailed view of the fuel injection module 2. An oil pump 20a, a pressure regulator 20b, an injector 20c, and an air conditioner 20d are integrated in the fuel injection module 2. For this purpose, a housing 25 is provided which is produced by injection molding from plastic. Among them, the pressure regulator 20b is an integral part of the injector 20c. A common actuator simultaneously operates the oil pump 20a and the air conditioner 20d. The common actuator includes a coil 21, a pump anchor 22, and a flat anchor 23 for the air conditioner. The outer casing 25 is closed by a cover 24.

As shown in Fig. 2, the pump anchor 22 has a circular design and is cylindrical. A passage 22a is thus created in the pump anchor 22, through which the fuel can flow from the supply pipe 6a to the return pipe 6b. The coil 21 is provided with an extrusion coating 21a surrounded by a magnetic circuit 40. The component symbols 41 and 42 denote a first magnetic separation point and a second magnetic separation point, respectively. The electrical connector 44 for the coil 21 is disposed on the side of the outer casing 25.

In addition to the pump anchor 22, the oil pump 20b also includes a cylindrical pump piston 26 and a cylindrical cylinder liner 35. The pump piston 26 is inserted in the cylinder liner 35. The first return spring 27 feeds the pump piston into the starting position shown in Figure 2, which is the one end of the suction stroke. An annular flange 26a for supporting the first return spring 27 is disposed on the pump piston 26. Pump piston 26 is coupled by bow 31 The annular pump anchors 22 are connected. The bow 31 may be non-fixedly disposed between the pump anchor 22 and the pump piston 26, or connected to one of the two components, or to both components. The other end of the first return spring 27 is supported on the inner annular flange portion 25c of the outer casing 25 (see Fig. 2).

The fuel injection module 2 further includes a suction chamber 30, and the oil supply pipe 6a is in communication with the suction chamber. The oil pump 20a is also disposed within the suction chamber 30. The suction chamber 30 includes an annular passage region 30a that is disposed adjacent the annular flange region 25c of the outer casing 25 in the bottom region of the suction chamber. The annular passage region 30a is separated from the remainder of the suction chamber 30 by a filter 37.

The oil pump 20a furthermore comprises a pump chamber 29 in which a pressure can be applied to the fuel to inject fuel into the oil suction pipe 8 by means of the injector 20c. The injector 20c is disposed at the end of the fuel injection member, and also includes and is integral with the pressure regulator 20b of the fuel injection module. The pressure regulator 20b includes a metering valve 32 and a check valve 33 that is biased by a third return spring 34. Therein, the third return spring 34 is supported on a support ring 38 which is fixed to the outer casing 25.

As shown in FIG. 2, the air conditioner 20d includes a flat anchor 23, a seal seat 43, and a plenum 45. The flat anchor 23 is fixed to the outer casing 25 by a second return spring 28, which in the present embodiment is an annular leaf spring. For example, the second return spring 28 can be secured between the outer casing 25 and the cover 24 by a clamping member. Seal seat 43 is illustrated in more detail in Figures 3 and 4. There are three partial annular through holes 51, 52, 53 in the sealing seat 43. The inside of the through holes 51, 52, 53 is defined by a protruding inner ring 54, and the outer side is defined by a protruding outer ring 55. The inner ring 54 and the outer ring 55 are actually formed for the dense The sealing surface of the flat anchor 23 is sealed. The area between the through holes 51, 52, 53 is slightly deeper than the sealing faces on the inner ring 54 and the outer ring 55, so that when the flat anchor 23 is opened, the entire ring between the inner ring 54 and the outer ring 55 can be opened. section. As shown in Fig. 2, the plenum 45 is disposed below the flat anchor 23, ensuring that the flat anchor 23 can perform an opening motion when the coil 21 is energized.

A connection passage 36 is also disposed between the suction chamber 30 and the pump chamber 29. The connecting passage 36 communicates with the annular passage region 30a of the suction chamber 30. Wherein, the connecting passage 36 includes an opening 35a on the cylinder liner 35 and an opening 25b in the annular flange portion 25c of the outer casing 25. From the axial X-X of the fuel injection module, the connecting passage 36 is arranged slightly below the dead point on the upper side of the pump piston 26. Thereby, the slit type gas distribution for the pressure recovery in the pump chamber 29 can be realized because the pressure can be achieved in the pump chamber 29 only when the pump piston 26 completely passes over the connecting passage 36, which is closed by the side wall of the pump piston 26. restore. The pressure surface 26b, to which the pump piston 26 is oriented toward the pump chamber 29, forms the control edge.

The function of the fuel injection module of the present invention is as follows. Figure 2 shows the pump piston at the end of the suction stroke. In this state, the coil 21 is energized, thereby moving the flat anchor 23 in the direction of the arrow A, and the annular pump anchor 22 is moved in the direction of the arrow B. It should be noted here that depending on the specific current intensity, it is also possible to move only by the flat anchor 23, whereby the air conditioner 20d is turned on, and the oil pump 20a is not manipulated. However, when the current intensity is sufficiently large, the air conditioner 20d and the oil pump 20a are simultaneously manipulated to move the flat anchor 23 on the one hand and the ring pump anchor 22 in the direction of the arrow B on the other hand. In this case, the pump piston 26 is also moved by the bow 31 in the direction of the arrow B. However, when the compression stroke starts, the pump chamber 29 does not occur yet. The pressure is restored because the pump piston 26 has not crossed the connecting passage 36. Only when the pump piston 26 has completely passed the connecting passage 36 will the pressure in the pump chamber 29 begin to recover. Once a sufficiently large pressure is reached within the pump chamber 29, the check valve 33 will open against the force of the return spring 34. At this time, the fuel can be injected into the oil suction pipe 8 from the pump chamber 29 by the metering valve 32. Here, the injection head can be controlled by selecting the diameter of the dosing valve 32 and the elastic force of the third return spring 34. Once the pressure in the pump chamber 29 drops again below the opening pressure, the third return spring 34 will re-feed the check valve 33 to the starting position, and the check valve 33 in the initial position is closely abutted in an integral manner. On the valve seat 25a on the outer casing 25, the pump chamber 29 is closed. This ends the fuel injection, and the energization of the coil 21 can also be ended. The first return spring 27 then re-feeds the pump piston 26 to the starting position, during which the annular pump anchor 22 is also reset by the bow 31. Once the pump piston 26 has passed the connecting passage 36, the process of drawing fuel from the annular passage region 30a into the pump chamber 29 begins. Since the inhaled fuel comes only from the annular passage region 30a, it is only necessary to filter the actually sucked fuel with the filter 37. The filter 37 thus has an extremely long service life.

Since the pump anchor 22 is axially drilled, the fuel can flow axially from the fuel supply pipe 6a to the return pipe 6b via the suction chamber 30 and the pump anchor 22. In this way, the flow of the fuel injection module can be achieved with minimal pressure loss. Since the fuel flows through the hollow tubular pump anchor 22, the waste heat of the coil 21 can be well absorbed. In this case, the fuel is heated up and flows back to the tank via the return line 6b. Thereby, the fuel circulation is realized during the operation of the fuel injection device, and continuous heat dissipation is realized by the oil return pipe 6b. The additional effect of this measure is if the fuel is heated When bubbles are generated, the bubbles can be ejected upward simply by the substantially vertically oriented bore 22a in the pump anchor 22.

Since the flat anchor 23 is also annular, a return path through the center of the fuel injection module can be set. This results in a very compact structure. It should be noted here that the magnetic circuit 40 can be designed as an insert into which the magnetic circuit can be injected when the outer casing 25 is manufactured by injection molding. The cylinder liner 35 is preferably pressed into the outer casing 25 by a press fit process. Thereby, the fuel injection module can be manufactured at a low cost and with a small number of parts.

5 and 6 show an alternative design of the flat anchor 23. The flat anchor 23 using this design also has three through holes 51, 52, 53. Here, the sealing seat is separately provided along the outer circumference of each of the through holes 51, 52, 53. The advantage of such an alternative flat anchor is that only a small force needs to be applied when opening, because the area of the alternative flat anchor that is in contact with the bypass tube 12 compared to the flat anchor shown in Figures 3 and 4 The area between the through holes 51, 52, 53 is not included.

It should be pointed out here that depending on the specific sealing requirements of the flat anchors 23, plastic elements, rubber elements or sealing coatings may be provided on one or both of the matching seals in order to achieve a better sealing effect.

Fig. 7 shows a fuel injection device according to a second embodiment of the present invention, in which components having the same or the same functions are given the same reference numerals as in the previous embodiment.

The second embodiment is basically identical to the first embodiment except that the second embodiment uses a slit type gas distribution method different from that of the first embodiment. As shown in Figure 7, the pump piston 26 is provided with an axial X-X orientation. Slot 50. The slot 50 connects the pump chamber 29 to the suction chamber 30 when the pump piston 26 is in a partial region above the pump piston stroke. In this case, only when the pump piston 26 is moved until the groove 50 is covered by the cylinder liner 35, the connection between the pump chamber 29 and the suction chamber 30 is released, and the pressure is again restored in the pump chamber 29. This pressure recovery is easily accomplished without the need to provide openings in the flange region 25c and the cylinder liner 35. The only disadvantage is that the total fuel volume flow must be filtered, since it is no longer possible to filter only the fuel that is sucked into the pump chamber 20. Therefore, the oil filter must be placed in the oil supply pipe 6a. This embodiment is in other respects in accordance with the previous embodiment, and thus the description given in the previous embodiment can be referred to.

The above embodiments all point to a fuel injection module 2 with a particularly tight structure. The annular design of the flat anchor 23 and the pump anchor 22 can realize the axial flow of fuel in the fuel injection module. This avoids heat-related problems because the fuel absorbs the heat generated by the device during its cycle and returns it to the tank. This allows for particularly high operational reliability.

1‧‧‧Small motor

2‧‧‧Injection module

3‧‧‧ cylinder

4‧‧‧ pump piston

5‧‧‧Control unit

6‧‧‧ fuel tank

6a‧‧‧Supply pipe

6b‧‧‧ return pipe

7‧‧‧ throttle valve

8‧‧‧ suction pipe

9‧‧Spark plug

10‧‧‧Into the valve

11‧‧‧Drain valve

12‧‧‧ Bypass

12z‧‧‧Export

13‧‧‧Exhaust pipe

14‧‧‧Oxygen sensor

15‧‧‧Cooling water sensor

16‧‧‧ oil temperature sensor

17‧‧‧Sensor unit

20a‧‧‧oil pump

20b‧‧‧pressure regulator

20c‧‧‧Injector

20d‧‧‧Air conditioner

21‧‧‧ coil

21a‧‧‧Extrusion coating

22‧‧‧ pump anchors

22a‧‧‧channel, drilling

23‧‧‧flat anchors

24‧‧‧ Cover

25‧‧‧Shell

25a‧‧‧ seat

25b‧‧‧ openings

25c‧‧‧ annular flange area

26‧‧‧ pump piston

26a‧‧‧Ring flange

26b‧‧‧pressure surface

27‧‧‧First return spring

28‧‧‧Second return spring

29‧‧‧ pump room

30‧‧‧Inhalation room

30a‧‧‧Circular passage area

31‧‧‧ Bow

32‧‧‧Quantitative valve

33‧‧‧ check valve

34‧‧‧ Third return spring

35‧‧‧Cylinder liner

35a‧‧‧ openings

36‧‧‧Connected channel

37‧‧‧Filter

38‧‧‧ support ring

40‧‧‧ Magnetic circuit

41‧‧‧First magnetic separation point

42‧‧‧Second magnetic separation point

43‧‧‧Sealing seat

44‧‧‧Electrical connectors

45‧‧‧Inflatable room

50‧‧‧ slots

51‧‧‧through hole

52‧‧‧through hole

53‧‧‧through hole

54‧‧‧ Inner Ring

55‧‧‧Outer Ring

A‧‧‧ arrow

B‧‧‧ arrow

1 is a schematic view of a small motor having a fuel injection device according to a first embodiment of the present invention; FIG. 2 is a schematic view of a fuel injection module using the fuel injection device of the first embodiment; 4 is a cross-sectional view taken along line IV-IV of FIG. 3; FIG. 5 is a plan view of an alternative sealing seat; FIG. 6 is a cross-sectional view taken along line VI-VI of FIG. 5; 7 is a fuel injection module using the fuel injection device of the second embodiment of the present invention. Schematic diagram.

2‧‧‧Injection module

6a‧‧‧Supply pipe

6b‧‧‧ return pipe

8‧‧‧ suction pipe

12‧‧‧ Bypass

12z‧‧‧Export

20a‧‧‧oil pump

20b‧‧‧pressure regulator

20c‧‧‧Injector

20d‧‧‧Air conditioner

21‧‧‧ coil

21a‧‧‧Extrusion coating

22‧‧‧ pump anchors

22a‧‧‧channel, drilling

23‧‧‧flat anchors

24‧‧‧ Cover

25‧‧‧Shell

25a‧‧‧ seat

25b‧‧‧ openings

25c‧‧‧ annular flange area

26‧‧‧ pump piston

26a‧‧‧Ring flange

26b‧‧‧pressure surface

27‧‧‧First return spring

28‧‧‧Second return spring

29‧‧‧ pump room

30‧‧‧Inhalation room

30a‧‧‧Circular passage area

31‧‧‧ Bow

32‧‧‧Quantitative valve

33‧‧‧ check valve

34‧‧‧ Third return spring

35‧‧‧Cylinder liner

35a‧‧‧ openings

36‧‧‧Connected channel

37‧‧‧Filter

38‧‧‧ support ring

40‧‧‧ Magnetic circuit

41‧‧‧First magnetic separation point

42‧‧‧Second magnetic separation point

43‧‧‧Sealing seat

44‧‧‧Electrical connectors

45‧‧‧Inflatable room

A‧‧‧ arrow

B‧‧‧ arrow

Claims (12)

An oil injection device comprising an oil pump (20a), a pressure regulator (20b), a fuel injector (20c) and an air conditioner (20d), the oil pump (20a), the fuel injector (20c) and the air conditioner (20d) is a bulk component of a compact fuel injection module (2), and the pressure regulator (20b) is a bulk component of the fuel injector (20c), characterized by: the oil pump (20a) ) comprising a pump piston (26), a pump anchor (22) and a pump chamber (29), the air regulator (20d) comprising a valve seat (54, 55) and a flat anchor (23), wherein the flat anchor (23) directly mating with the valve seat (54) (55) to open and close the air conditioner (20d), the pump anchor (22) and the flat by a common coil (21) The anchor (23) is manipulated. The fuel injection device of claim 1, wherein the pump anchor (22) is annular, and a fuel return path passes through the annular pump anchor. The fuel injection device of claim 1 or 2, wherein the flat anchor (23) of the air conditioner (20d) is designed to be annular. The fuel injection device of claim 3, wherein the fuel return path passes through the annular flat anchor (23). The fuel injection device of claim 1 or 2, wherein the flat anchor (23) is fixed to the outer casing (25) by a return spring (28). The fuel injection device of claim 1 or 2, wherein: the connection passage between the pump chamber (29) and the suction chamber (30) as seen from the axial direction (XX) of the pump piston (26) (36) disposed in the pump piston Below the dead side of the upper side. The fuel injection device of claim 6, wherein the connecting passage (36) is in communication with the annular passage region (30a) below the suction chamber (30). The fuel injection device of claim 7, wherein a filter (37) is disposed between the annular passage region (30a) below the suction chamber (30) and the main portion. The fuel injection device of claim 6, wherein the pump piston (26) has a gap (50), in particular a longitudinal groove, which extends continuously on the outer circumference of the pump piston (26). a pressure surface directed to the pump chamber (26) toward the pump chamber, the gap (50) being established between the pump chamber (29) and the suction chamber (30) at the beginning of the pressure recovery phase of the oil pump (20a) Connection, the connection is released after the pump piston (26) has passed a certain length of travel. The fuel injection device of claim 1 or 2, wherein the pump piston (26) is disposed in a cylinder liner (35), the cylinder liner being fixed in the outer casing (25). The fuel injection device of claim 1 or 2, wherein the pressure regulator (20b) comprises an open-out valve member (33), and a spring member that applies a pre-force to the valve member (33) (34) And a dosing valve (32) to adjust the injection pressure. An internal combustion engine comprising one or two cylinders and an oil injection device according to any one of the above items 1 to 11.