KR101692231B1 - Injection pump - Google Patents

Abstract

The present invention relates to an injection pump for an internal combustion engine, wherein the injection pump comprises a pump body (2), a first fluid chamber (15) arranged inside the pump body (2) and in fluid communication with each other and a second fluid chamber 16, a first reciprocating plunger 3 protruding into the first fluid chamber 15, a second plunger 4 at least partially disposed inside the second fluid chamber 16, a first fluid chamber 15, And a second fluid port (12) in fluid communication with a first fluid port (11) and a second fluid chamber (16) in fluid communication. The fluid supply channel 10 is in fluid communication with the first fluid chamber 15 and / or the second fluid chamber 16 through the first fluid port 11 and / or the second fluid port 12, (14) is in fluid communication with the first fluid chamber (15) and / or the second fluid chamber (16). The first plunger 3 and the second plunger 4 have different diameters.

Description

Injection Pump {INJECTION PUMP}

The present invention relates to an injection pump for an internal combustion engine as defined in the preamble of claim 1.

As a fuel injection pump of a compression ignition internal combustion engine, an injection pump capable of generating a high injection pressure is needed. In a particularly large internal combustion engine, a similar injection pump may also be used to inject other fluids such as water to reduce the emission of the engine. The expression large internal combustion engine is used here to denote an engine used, for example, in a power plant or used as a main or auxiliary engine of a ship.

EP 0715070 A1 discloses an injection pump for injecting a pressure medium into the cylinder of an internal combustion engine. The pump includes two reciprocating piston members disposed inside the common pump body. The piston member is provided with a control edge such that the control edge of the piston member of one of the piston members determines the moment of initiation of injection and the control edge of the other piston member determines the end of injection. With this kind of injection pump a high injection pressure can be achieved and the injection timing can be controlled. However, the configuration of EP 0715070 A1 is somewhat fragile with respect to fluid flow between the chambers in which the piston member is disposed. The composition is also intended to be effectively sealed.

An object of the present invention is to provide an improved injection pump for an internal combustion engine. The characteristic features of the injection pump according to the invention are provided in the characterizing part of claim 1.

According to the present invention, an injection pump for an internal combustion engine includes a pump body, a first fluid chamber disposed inside the pump body, and a second fluid chamber. The first fluid chamber and the second fluid chamber are in fluid communication with each other. The first reciprocating plunger is disposed inside the pump body and projects into the first fluid chamber. The pump further includes a second plunger disposed at least partially within the second fluid chamber, wherein the first fluid port is in fluid communication with the first fluid chamber and the second fluid port is in fluid communication with the second fluid chamber, The fluid supply channel is in fluid communication with the first fluid chamber and / or the second fluid chamber through the first fluid port and / or the second fluid port, and the fluid outlet is in fluid communication with the first fluid chamber and / do. According to the present invention, the first plunger and the second plunger have different diameters.

When one of the plungers has a smaller diameter than the other, fluid flow between the first fluid chamber and the second fluid chamber decreases. The pump body can also be made smaller. A further advantage of the present invention is that the sealing of the injection pump can be improved.

According to an embodiment of the present invention, the diameter of the second plunger is smaller than the diameter of the first plunger. According to another embodiment of the invention, the diameter of the second plunger is less than 50 percent of the diameter of the first plunger. According to a further embodiment of the present invention, the diameter of the second plunger is less than 15 percent of the diameter of the first plunger.

According to an embodiment of the present invention, the first plunger is arranged to control the starting point of the fluid injection, and the second plunger is arranged to control the end point of the fluid injection. If the diameter of the second plunger is smaller than the diameter of the first plunger, less force is required to rotate the second plunger. In many cases, the endpoint of the injection is adjusted more often than the beginning of the injection, and therefore it would be advantageous to use the second plunger to control the endpoint of the fluid injection.

According to an embodiment of the present invention, the second plunger is arranged to control the starting point of the fluid injection and the first plunger is arranged to control the end point of the fluid injection.

According to an embodiment of the present invention, the first plunger includes a rotationally asymmetric cutout to allow outflow from the first fluid chamber when in fluid communication with the first fluid port. According to another embodiment of the invention, the injection pump comprises means for rotating the first plunger. The cutout and rotation means enable adjustment of the starting and / or ending point of the fluid injection.

According to an embodiment of the present invention, the second plunger includes a rotationally asymmetric cutout for allowing outflow from the second fluid chamber when in fluid communication with the second fluid port. According to another embodiment of the invention, the injection pump comprises means for rotating the second plunger. The cutout and rotation means enable adjustment of the starting and / or ending point of the fluid injection.

According to an embodiment of the present invention, the injection pump includes a third fluid port in fluid communication with the first fluid chamber. If the first fluid chamber comprises two separate fluid ports, one of the fluid ports may be used to introduce fluid into the fluid chamber, while the other may be used to relieve pressure from the chamber at the end of the injection .

According to an embodiment of the present invention, the injection pump includes a connecting duct for connecting the first fluid chamber to the second fluid chamber.

According to an embodiment of the present invention, the connecting duct is arranged to connect the outlet ends of the first and second fluid chambers.

According to an embodiment of the present invention, the ends of the connecting duct are disposed apart from both ends of the first fluid chamber and the second fluid chamber.

According to an embodiment of the present invention, the fluid outlet is in fluid communication only with the first fluid chamber.

When the connecting duct is arranged so as not to connect with the ends of the fluid chamber and when the fluid outlet is in fluid communication only with the first fluid chamber, the second plunger is connected to the connecting duct by the second plunger so that the second plunger is not used to pressurize the fluid To be intercepted. This is advantageous because a better efficiency of the pump can be achieved. And the pressure in the second fluid chamber is kept low.

According to an embodiment of the present invention, the first and second fluid ports are in fluid communication with the fluid supply channel. When the same fluid port operates as a fluid inlet and spill port, separate ducts for collecting excess fluid are not required.

According to an embodiment of the present invention, the injection pump includes thrust means for moving the first plunger.

According to an embodiment of the present invention, the second plunger is arranged to be moved by the thrust means. Further, when the second plunger is moved by thrust means such as the first plunger, the jet pump can be driven by a single cam of the camshaft.

According to an embodiment of the present invention, the injection pump is a fuel injection pump.

1 shows an injection pump according to an embodiment of the present invention.
Figure 2 shows the injection pump of Figure 1 at the end of the compression stroke.
Figure 3 shows a design option for the second plunger.
Figure 4 shows another design option for the second plunger.
Figure 5 shows an injection pump according to another embodiment of the present invention.
Figure 6 shows an injection pump according to yet another embodiment of the present invention.
Fig. 7 shows the injection pump using the electric injection timing.

BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the invention will be described in more detail with reference to the accompanying drawings. The injection pump 1 according to an embodiment of the present invention is shown in Figs. 1 and 2. Fig. The pump 1 is used, for example, to pressurize a fluid, such as fuel, which is injected through a nozzle 25 into a cylinder of an internal combustion engine. The injection pump (1) includes a pump body (2). The pump body 2 is formed of a lower body part 2a and an upper body part 2b. On the inside of the pump body 2, an internal body part 20 is provided. The cylindrical space inside the inner body part (20) forms the first fluid chamber (15). Further, there is a cylindrical space inside the inner body part 20 forming the second fluid chamber 16. The first reciprocating plunger 3 projects into the first fluid chamber 15 and the second plunger 4 projects into the second fluid chamber 16. The first plunger (3) is attached to a thrust means (5) which can reciprocate inside the pump body (2). The thrust means 5 includes a roller 5a which is rotatable against the cam 6 of the camshaft. The second plunger (4) is attached to the same thrust means (5) as the first plunger (3). The injection pump 1 is also provided with a spring 29 which is arranged to push the thrust means 5 outwardly, i.

The first plunger 3 and the second plunger 4 have different diameters. In the embodiments shown in the drawings, the diameter of the second plunger 4 is smaller than the diameter of the first plunger 3. Due to the difference in diameter, fluid flow between the first fluid chamber 15 and the second fluid chamber 16 is reduced. Also, the pump body 2 can be made smaller.

The peripheral fluid supply channel 10 is disposed between the pump body 2 and the inner body part 20. [ The perforation of the inner body part 20 includes a first fluid port 11 and a second fluid port 12 connecting the first fluid chamber 15 and the second fluid chamber 16 to the fluid supply channel 10 . There is also a third fluid port 13 connecting the first fluid chamber 15 to the fluid supply channel 10. A fluid outlet (14) is connected to the first and second fluid chambers (15, 16). A check valve 17 including a spring 17a is disposed in the fluid outlet 14 to prevent back flow into the first and second fluid chambers 15,16.

The first plunger (3) is provided with a cutout (18). The cutout portion 18 includes a longitudinal section 18a disposed between the peripheral section 18c and the peripheral section 18c and the end of the first plunger 3. The longitudinal section 18a is widened toward the peripheral section 18 forming the inclined section 18b.

When the roller 5a is on the base circle 6a of the cam 6, the first and second plungers 3, 4 are in their outermost positions. The cutout portion 18 of the first plunger 3 is aligned with the third fluid port 13 and the second plunger 4 does not cover the second fluid port 12. [ The fluid to be injected can flow from the fluid supply channel 10 to the first fluid chamber 15 through the third fluid port 13 and into the second fluid chamber 16 through the second fluid port 12 have.

When the cam 6 rotates, the roller 5a is engaged with the cam race 6b of the cam 6 and starts to push the thrust means 5 inward. Unless the third fluid port 13 and / or the second fluid port 12 are covered by the outer surface of the first plunger 3 and the second plunger 4, the first and second fluid chambers 15 , 16) can flow back to the fluid supply channel (10) and the check valve (17) remains closed. When the first and second plungers 3, 4 move inwardly, the outer surface thereof will eventually cover the third and the second fluid ports 13, 12 and the fluid will flow into the fluid supply channel 10 ≪ / RTI > The pressures of the first and second fluid chambers 15 and 16 begin to increase and eventually the check valve 17 opens to allow fluid to flow out of the fluid chambers 15 and 16. When the plungers 3, 4 move further inward, the first plunger 3 eventually reaches the position shown in Fig. In this position, the peripheral section 18c of the cut-out portion 18 of the first plunger 3 is aligned with the first fluid port 11. The fluid in the first chamber 15 can flow from the fluid chamber 15 to the fluid supply channel 10 and the pressure in the first and second fluid chambers 15, Lt; / RTI >

The fluid injection timing can be adjusted by the second plunger 4. The second plunger 4 is provided with means 9 for rotating the plunger 4 and this means 9 includes a rack 9a and a pinion 9b. When the rack 9a is moved, the rack rotates the pinion 9b attached to the extension of the second plunger 4. At the inner end of the second plunger 4, a cutout 19 is provided as shown in Figs. When the second plunger 4 is rotated, the second plunger can be affected when the second fluid port 12 is blocked by the second plunger 4, and the starting point of the fluid injection can be adjusted accordingly . In the embodiment of Figure 3, the second plunger 4 has a free end, i. E., A cutout 19 tapered at the inner end of the plunger 4. Thus, by rotating the second plunger 4, the plunger 4 can be steplessly adjusted when the second fluid port 12 is blocked and the injection is initiated. In the embodiment of Figure 4, the second plunger 4 includes a step cutout 19. When the second plunger 4 is rotated to the position shown on the left, the latest possible injection timing is used. When the second plunger is in the position shown on the right, the earliest possible timing is used. The center position is used for the intermediate injection timing.

The amount of fluid injected can be controlled by the first plunger (3). The first plunger 3 is also provided with a rack 8a and a pinion 8b so that the first plunger 3 can be rotated in a manner similar to the second plunger 3. [ When the first plunger 3 is rotated the first plunger can be affected when the cutout portion 18 is aligned with the first fluid port 11 and the pressure in the fluid chambers 15, And thus the injection is terminated.

The embodiment of Fig. 5 is similar to that of the first and second embodiments. The injection pump 1 of Fig. 5 differs from the injection pump 1 of Figs. 1 and 2 in that it does not include a third fluid port. Another difference between these two embodiments is that the fluid outlet 14 is only connected to the first fluid chamber 15 in the embodiment of FIG. The first fluid chamber (15) and the second fluid chamber (16) are interconnected by a connecting duct (22). The connecting duct 22 is positioned such that the outlet ends of the fluid chambers 15, 16 are connected to each other. 5, the second plunger 4 is not moved directly by the thrust means 5, but the push rod 23 connected to the thrust means 5 moves the second plunger 4 . A gap 24 may be left between the push rod 23 and the second plunger 4 when the thrust means 5 is not at its innermost position, i.e. at the end of the compression stroke. By adjusting the gap 24, the injection timing can be affected. When the large gap 24 is left between the push rod 23 and the second plunger 4 when the roller 5a of the thrust means is in the base circle of the cam 6, the push rod 23 and the plunger 4 ) Are in contact with each other, the second plunger 4 is not moved, so that the later injection timing is achieved. If the gap 24 is small or even when the push rod 23 and the second plunger 4 are in contact with each other when the roller 5a is in the base circle 6a of the cam 6, . The second spring 30 is arranged to push the second plunger 4 outwardly, that is, toward the cam 6.

In the embodiment of Figure 5, the first fluid chamber 15 comprises only one fluid port 11. [ Thus, prior to the initiation of injection, the fluid may flow through the first fluid port 11 into the first fluid chamber 15. The end point of injection depends on the instant at which the cutout portion 18 of the first plunger 3 is aligned with the first fluid port 11.

Fig. 6 shows yet another embodiment of the present invention. In the embodiment of Figure 6, the fluid outlet 14 is only connected to the first fluid chamber 15. Instead of the fluid outlet 14, the first fluid chamber 15 and the second fluid chamber 16 are connected by a connecting duct 22 similar to that in the embodiment of Fig. The main difference between the embodiment of FIG. 5 and the embodiment of FIG. 6 is that the connecting duct 22 does not connect the outlet ends of the fluid chambers 15, 16 in the embodiment of FIG. Instead, the connecting duct 22 is disposed approximately at the center of the first and second fluid chambers 15,16. Thus, the second plunger 4 is not used to pressurize the fluid, but merely controls the injection timing. The injection starts when the second plunger 4 closes the connecting duct 22 between the first fluid chamber 15 and the second fluid chamber 16. The second fluid chamber 16 is not in fluid communication with the first fluid chamber 15 or the fluid outlet 14 when the connecting duct 22 is blocked by the second plunger 4. The advantage of this embodiment is that only the first plunger 3 is used to pressurize the fluid, thus improving the efficiency of the pump. Another advantage of the embodiment of FIG. 6 is that the pressure in the second fluid chamber 16 is lowered during injection.

In the embodiment of Fig. 7, the second fluid chamber 16 is disposed in the upper body part 2b of the pump body 2. The second plunger 4 is not moved by the thrust means 5 directly. Instead, the second plunger 4 is a valve member that is moved by the electric actuator 26. When the cutout portion 19 of the second plunger 4 is aligned with the second fluid port 12 and the connecting duct 22 fluid flows from the first fluid chamber 15 to the second fluid chamber 16 , And further flow into the fluid supply channel (10). The spindle 27 of the linear position sensor 28 is attached to the thrust means 5. When the spindle 27 reaches a predetermined position, the valve actuator 26 receives a signal to shut off the fluid connection between the first and second fluid chambers 15,16. The second plunger 4 is moved to prevent fluid flow to the second fluid chamber 16 and the fluid flows through the fluid outlet 14 to the injection nozzle 25.

It will be appreciated by those skilled in the art that the present invention is not limited to the embodiments described above, but may be varied within the scope of the appended independent claims. For example, there are various possible designs for the cutout portion of the plunger. A separate thrust means may be provided for moving the first plunger and the second plunger, and the thrust means may be disposed outside the pump body. In addition, the first plunger may be arranged to control the starting point of the injection, while the second plunger may be arranged to control when the injection is finished. Any one of the plungers may have a smaller diameter than the other. Features from the above-described different embodiments can also be combined.

Claims (17)

An injection pump (1) for an internal combustion engine,
The injection pump (1)
- the pump body (2),
A first fluid chamber (15) and a second fluid chamber (16) disposed inside the pump body (2) and in fluid communication with each other,
A first reciprocating plunger (3) disposed inside the pump body (2) and projecting into the first fluid chamber (15)
- a second plunger (4) at least partially disposed inside said second fluid chamber (16) and having a diameter different from said first plunger (3)
- a first fluid port (11) in fluid communication with said first fluid chamber (15)
- a second fluid port (12) in fluid communication with said second fluid chamber (16)
- a fluid supply channel (10) in fluid communication with the first fluid chamber (15) and / or the second fluid chamber (16) through the first fluid port (11) and / ), And
- a fluid outlet (14) in fluid communication with said first fluid chamber (15) and / or said second fluid chamber (16)
- a roller (5a) capable of rotating against the cam (6) of the camshaft, the thrust means (5) for moving the first plunger (3) and the second plunger (4)
/ RTI >
Characterized in that the diameter of the second plunger (4) is less than 15 percent of the diameter of the first plunger (3). The method according to claim 1,
Characterized in that the first plunger (3) is arranged to control the starting point of the fluid injection and the second plunger (4) is arranged to control the end point of the fluid injection. The method according to claim 1,
Characterized in that the second plunger (4) is arranged to control the starting point of the fluid injection and the first plunger (3) is arranged to control the end point of the fluid injection. The method according to claim 1,
The first plunger 3 includes a rotationally asymmetric cutout 18 that permits outflow from the first fluid chamber 15 when in fluid communication with the first fluid port 11 As the injection pump. The method according to claim 1,
Characterized in that the injection pump (1) comprises means (8a, 8b) for rotating the first plunger (3). The method according to claim 1,
Characterized in that the second plunger (4) comprises a rotational asymmetric cutout (19) which permits outflow from the second fluid chamber (16) when in fluid communication with the second fluid port (12) As the injection pump. 7. The method according to any one of claims 1 to 6,
Characterized in that the injection pump (1) comprises means (9a, 9b) for rotating the second plunger (4). 7. The method according to any one of claims 1 to 6,
Characterized in that the injection pump (1) comprises a third fluid port (13) in fluid communication with the first fluid chamber (15). 7. The method according to any one of claims 1 to 6,
Characterized in that the injection pump (1) comprises a connecting duct (22) connecting the first fluid chamber (15) to the second fluid chamber (16). 10. The method of claim 9,
Characterized in that the connecting duct (22) is arranged to connect the outlet ends of the first fluid chamber and the second fluid chamber (15, 16). 10. The method of claim 9,
Characterized in that the ends of the connecting duct (22) are spaced apart from both ends of the first fluid chamber (15) and the second fluid chamber (16). 7. The method according to any one of claims 1 to 6,
Characterized in that said fluid outlet (14) is only in fluid communication with said first fluid chamber (15). 7. The method according to any one of claims 1 to 6,
Characterized in that the first fluid port and the second fluid port (11, 12) are in fluid communication with the fluid supply channel (10). 7. The method according to any one of claims 1 to 6,
Characterized in that the injection pump (1) is a fuel injection pump. delete delete delete

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