JP3884665B2 - Accumulated distribution fuel injection pump - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a configuration of an electronically controlled accumulator-type distributed fuel injection pump that distributes and supplies high-pressure fuel accumulated in an accumulator to each cylinder by a distribution means.
[0002]
[Prior art]
In recent years, exhaust emission regulations in diesel engines have become more and more strict, and it is desired to reduce fuel consumption and reduce NOx and particulates. To meet this demand, fuel is required to improve combustion efficiency. Increasing injection pressure is progressing.
[0003]
Along with the increase in fuel injection pressure, accumulator fuel injection pumps that inject high-pressure fuel accumulated in an accumulator chamber from an injection valve are increasing. In this accumulator fuel injection pump, the high-pressure fuel accumulated in the accumulator chamber is supplied to the distribution shaft through the injection control valve, distributed to each cylinder by the distribution shaft, and then the high-pressure injection from the injection valve is performed. There is one configured as a distributed fuel injection pump.
[0004]
[Problems to be solved by the invention]
[0005]
In the accumulator-type distributed fuel injection pump, the fuel gallery for supplying fuel to the plunger chamber of the feed pump and the fuel gallery for storing the return fuel from the injection nozzle are usually a common chamber, The pressure in this chamber is set to a relatively high pressure of about 2 MPa because of the need to ensure the residual pressure in the injection pipe even during high-pressure injection. For this reason, a relatively expensive pump having a high pressure and a large capacity is required.
[0006]
[Means for Solving the Problems]
The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.
[0007]
According to claim 1, in a pressure-accumulation-type distributed fuel injection pump that supplies high-pressure fuel accumulated in a pressure accumulation chamber (31) to each cylinder by a distribution shaft (9), the plunger (7) for pumping fuel is supplied. A supply pump side fuel gallery (57) connected to the plunger chamber (7a) and an injection control valve side fuel gallery (56) connected to the injection control valve (26) are configured independently, and each supply pump side fuel gallery (57 ) And the injection control valve side fuel gallery (56), the fuel is pumped from the feed pump side feed pump (60) and the injection control valve side feed pump (61) which are different feed pumps .
[0008]
In the pressure accumulation type fuel injection pump for distributing and supplying the high pressure fuel accumulated in the pressure accumulation chamber (31) to each cylinder by the distribution shaft (9), the plunger (7) for pumping the fuel is provided. A supply pump side fuel gallery (57) connected to the plunger chamber (7a) and an injection control valve side fuel gallery (56) connected to the injection control valve (26) chamber are configured independently, and the supply pump side fuel gallery ( 57), the fuel is pumped from the supply pump side feed pump (60), and the fuel stored in the pressure accumulating chamber (31) is supplied to the injection control valve side fuel gallery (56) by the pressure reducing valve (58). It supplies it via .
[0009]
According to a third aspect of the present invention, in the accumulator-type distributed fuel injection pump according to the first or second aspect, an oil passage (77) between the discharge valve (18) and the distribution shaft (9) is provided for a predetermined period after the end of injection. ) Or the oil passage (77, 78) between the injection nozzle (29) and the distribution shaft (9) is communicated with the injection control valve side fuel gallery (56) .
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of the present invention will be described.
[0011]
FIG. 1 is a schematic view showing a state of fuel injection in the fuel injection pump according to the present invention, FIG. 2 is a schematic view showing the state of the fuel injection pump when no fuel is injected, and FIG. 3 is a cross-sectional view showing the fuel injection pump. FIG. 4 is a plan view of the same.
[0012]
FIG. 5 is a cross-sectional view showing the injection control valve, FIG. 6 is a cross-sectional view showing the pressure accumulating chamber of the fuel injection pump, and FIG. 7 is a cross-sectional view showing the injection control valve.
[0013]
FIG. 8 is a view showing a fuel pipe, and FIG. 9 is a view showing another embodiment of the fuel pipe. 10 is a sectional view showing a safety valve, FIG. 11 is a sectional view showing a valve body of the safety valve, and FIG. 12 is a sectional view showing a structure of a conventional safety valve.
[0014]
First, a schematic configuration of a pressure accumulating distribution type fuel injection pump according to the present invention will be described. As shown in FIGS. 1 to 4, a fuel injection pump 1 configured as an accumulator-type distributed fuel injection pump includes an accumulator chamber 31 that accumulates high-pressure fuel, a plunger 7 that pumps fuel to the accumulator chamber 31, and an accumulator chamber. A distribution shaft 9 and the like that distribute and supply fuel pumped from 31 to the injection nozzles 29 of each cylinder are provided.
[0015]
The plunger 7 is driven to slide up and down via a tappet 11 by a cam 5 formed on the cam shaft 4, and a plunger chamber 7 a formed above the plunger 7 is connected to a pressure accumulating chamber via a check valve 28. 31 is connected. The plunger chamber 7 a is connected to the low-pressure side oil passage 32 via the pressure control valve 27. The plunger chamber 7a and the low-pressure side oil passage 32 are separated when the pressure control valve 27 is on, and the plunger chamber 7a and the low-pressure side oil passage 32 communicate with each other when the pressure control valve 27 is off.
[0016]
An injection control valve 26 is connected to the pressure accumulating chamber 31 via an oil passage 75, a distribution shaft 9 is connected to the injection control valve 26 via an oil passage 76, and the distribution shaft 9 is connected to an injection nozzle 29. It is configured to be able to communicate with the discharge valve 18 of each cylinder. A damping valve 50 is interposed between the oil passage 75 and the injection control valve 26. In addition, a safety valve 24 is connected to the pressure accumulating chamber 31 and a pressure sensor 30 for detecting the pressure in the pressure accumulating chamber 31 is attached, so that the pressure in the pressure accumulating chamber 31 becomes a predetermined pressure or higher. The pressure is released to the low-pressure side drain oil passage 100.
[0017]
As shown in FIG. 5, an inlet side valve body 40, an outlet side valve body 42, and a command piston 43 are slidably accommodated in the injection control valve 26, and the inlet side valve body 40 is slid by a spring 41. It is biased toward the pressure accumulation chamber 31 side. The injection control valve 26 is configured as a so-called three-way valve, and in a state where the inlet side valve body 40 slides toward the counter pressure storage chamber 31 side, the pressure storage chamber 31 is connected via the distribution shaft 9 and the discharge valve 18. In the state where the inlet side valve body 40 is slid toward the pressure accumulating chamber 31, the discharge valve 18 and the low pressure side oil passage 32 communicate with each other via the distribution shaft 9 and the oil passage 77. It is configured.
[0018]
An end portion of the injection control valve 26 on the side opposite to the pressure accumulating chamber 31 is connected to the pilot valve 25 via the control chamber 34, and the control chamber 34 is connected to the pressure accumulating chamber 31 via the bypass oil passage 33. The pilot valve 25 connects and disconnects the communication between the control chamber 34 and the low pressure side oil passage 32. When the pilot valve 25 is in the on state, the control chamber 34 and the low pressure side oil passage 32 communicate with each other, and the off state is established. At this time, the control chamber 34 and the low-pressure side oil passage 32 are divided. The pilot valve 25, the pressure control valve 27, and the pressure sensor 30 are connected to an electronic control unit (hereinafter referred to as “ECU”) 20.
[0019]
In the fuel injection pump 1 configured as described above, the fuel is supplied from the fuel tank 70 into the plunger chamber 7a, and the pressure control valve 27 is turned on by the control of the ECU 20 as shown in FIG. Thus, the plunger chamber 7 a and the low pressure side oil passage 32 are divided, and the fuel in the plunger chamber 7 a is compressed by the plunger 7 that slides upward by the cam 5 and is pumped to the pressure accumulating chamber 31. The fuel pumped to the pressure accumulating chamber 31 is prevented from flowing back by the check valve 28, and the pressure in the pressure accumulating chamber 31 is appropriately accumulated to a pressure. On the other hand, when pressure accumulation is not required, as shown in FIG. 2, the pressure control valve 27 is turned off and the plunger chamber 7a communicates with the low-pressure side oil passage 32, and the fuel in the plunger chamber 7a is drained to the low-pressure side oil passage. Is done.
[0020]
The control chamber 34 connected to the pressure accumulating chamber 31 by the bypass oil passage 33 is supplied with fuel from the pressure accumulating chamber 31 through a throttle 33a. At the time of fuel injection, when the pilot valve 25 of the injection control valve 26 is turned on by the control of the ECU 20 and the control chamber 34 and the low pressure side oil passage 32 are communicated with each other, the pressure in the control chamber 34 decreases. The pressing of the command piston 43 toward the pressure accumulation chamber 31 is released. Therefore, the inlet side valve body 40 is urged toward the counter pressure accumulating chamber 31 by the pressure of the pressure accumulating chamber 31 and slides toward the counter pressure accumulating chamber 31, and the pressure accumulating chamber 31 and the distribution shaft 9 communicate with each other. As a result, the fuel in the pressure accumulating chamber 31 is pumped to the distribution shaft 9 and distributed to each cylinder, and is injected from the injection nozzle 29 via the discharge valve 18.
[0021]
On the other hand, at the time of no fuel injection, as shown in FIG. 2, the pilot valve 25 of the injection control valve 26 is turned off by the control of the ECU 20, and the control chamber 34 to which fuel is supplied from the pressure accumulating chamber 31 via the throttle 33a and the low pressure side. Since the oil passage 32 is disconnected, the pressure in the control chamber 34 is increased by the supplied fuel, and the command piston 43 of the injection control valve 26 is pressed toward the pressure accumulation chamber 31. As a result, the inlet side valve body 40 slides toward the pressure accumulating chamber 31 via the outlet side valve body 42, and the oil passages 76 and 77 between the injection control valve 26 and the discharge valve 18 and the low pressure side oil passage 71. Communicates with each other, and the pressure in the fuel injection pipe is lowered to terminate the injection. The spring 41 urges the inlet side valve body 40 toward the pressure accumulation chamber 31 and is a spring for increasing the pressure of the pressure accumulation chamber 31 at the time of activation.
[0022]
Next, the arrangement configuration of each component of the fuel injection pump 1, such as the plunger 7, the pressure accumulating chamber 31, the distribution shaft 9, the pressure control valve 27, and the pilot valve 25 will be described.
[0023]
As shown in FIGS. 3 and 4, a cam shaft 4 to which a cam 5 is fixed is laterally provided at a lower portion of the fuel injection pump 1, and one end portion of the cam shaft 4 is connected to a cam shaft via a cam bearing 12. The housing 2 is rotatably supported by the shaft. Above the camshaft housing 2, a block-shaped hydraulic head 3, which is a housing for each component of the fuel injection pump 1 such as the plunger 7, the pressure accumulating chamber 31, and the shaft 9, is connected.
[0024]
A cam 5 is disposed below a cam shaft 4 that is disposed in a substantially orthogonal direction with respect to a plunger 7 that is slidably inserted in a plunger barrel 8 that is fitted to the hydraulic head 3. The tappet 11 attached to the lower end of the plunger 7 abuts on the cam 5 and is biased downward by a biasing means such as a spring 16 so that the plunger 7 reciprocates up and down by the rotation of the cam 5. Has been.
[0025]
Further, the pressure control valve 27 which is an electromagnetic valve for controlling the fuel pressure by the plunger 7 is disposed at the upper end of the plunger 7, and the pressure control valve 27 has a valve body in the axial direction of the camshaft 4. It arrange | positions so that it may slide to the direction substantially orthogonal, ie, an up-down direction.
[0026]
Further, on the side of the plunger 7, a distribution shaft 9 is arranged in parallel with the plunger 7, and the distribution shaft 9 rotates on a distribution shaft sleeve 10 fitted to the hydraulic head 3. It is freely inserted and rotated by a distribution drive shaft 39 connected to the lower end of the distribution shaft 9. The distribution drive shaft 39 and the distribution shaft 9 are arranged in a direction substantially orthogonal to the axial direction of the cam shaft 4, and the distribution drive shaft 39 and the cam shaft 4 are connected by a bevel gear 19. Thereby, the distribution shaft 9 can be rotationally driven by the cam shaft 4 via the bevel gear 19. A discharge valve 18 corresponding to the number of cylinders is fitted around the distribution shaft 9 in the hydraulic head 3.
[0027]
Further, in the hydraulic head 3, a fitting insertion hole 3 c is formed in a side portion of the distribution shaft 9 on the side opposite to the plunger 7, and the injection control valve 26 is fitted therein, and the axial direction of the cam shaft 4. Are arranged in a direction substantially orthogonal to That is, the injection control valve 26 is disposed so that the inlet side valve body 40 and the outlet side valve body 42 slide in a direction substantially orthogonal to the axial direction of the cam shaft 4. The pilot valve 25 is disposed at the upper end of the injection control valve 26. The pilot valve 25 is slid in a direction substantially perpendicular to the axial direction of the cam shaft 4, that is, in the vertical direction. It is arranged to move.
[0028]
The plunger 7, the distribution shaft 9 and the injection control valve 26, which are functional members of the fuel injection pump 1, are disposed in the hydraulic head 3, and the cam shaft 4 extends from one end side of the hydraulic head 3. In the axial direction, the plunger 7, the distribution shaft 9, and the injection control valve 26 are arranged substantially in series in this order.
[0029]
Further, as shown in FIG. 6 and FIG. 7, the hydraulic head 3 has a long hole in the axial direction substantially parallel to the axial direction of the camshaft 4 to constitute a pressure accumulating chamber 31. A plurality of the pressure accumulating chambers 31 are configured and communicated with each other by an oil passage formed in the hydraulic head 3. One end of the hole of the hydraulic head 3 constituting the pressure accumulating chamber 31 is opened to the outside, and this opening is closed by a plug, a pressure sensor 30 for detecting the pressure in the pressure accumulating chamber 31, a safety valve 24, and the like. Yes. In the present configuration example, among the plurality of pressure accumulation chambers 31, the opening of the hole constituting one pressure accumulation chamber 31 is blocked by the safety valve 24, and the opening of the hole constituting the other pressure accumulation chamber 31 is blocked by the pressure sensor 30. is doing. The plurality of pressure accumulating chambers 31 are arranged in parallel to each other, and are arranged in the vicinity of control system functional members such as the plunger 7, the distribution shaft 9, and the injection control valve 26.
[0030]
When the pilot valve 25 is controlled to be turned on, the high-pressure fuel delivered into the pressure accumulating chamber 31 is introduced into the injection control valve 26 through the oil passage 75, and from the injection control valve 26 through the oil passage 76. Derived to the distribution axis 9. The fuel sent to the distribution shaft 9 is guided to the discharge valve 18 through the oil passage 77 corresponding to each cylinder, and is injected from the injection nozzle 29 of each cylinder.
[0031]
As described above, the plunger 7, the distribution shaft 9, the pressure control valve 27, and the check valve 28 that constitute the high-pressure path of the fuel in the fuel injection pump 1 are connected to the hydraulic head 3 constituted by one block-like member. In addition, functional members such as the injection control valve 26, the pressure sensor 30, the safety valve 24, the discharge valve 18, the pilot valve 25, and the pressure accumulating chamber 31 are collectively arranged.
[0032]
On the other hand, as shown in FIGS. 3 and 8, the camshaft housing 2 is integrally formed with a pump portion 2a in which an injection control valve side feed pump 61 is housed. A drive shaft 61a of the feed pump 61 is connected to the side end. The drive shaft 61 a rotates in synchronization with the cam shaft 4 to drive the feed pump 61, and the fuel stored in the fuel tank 70 by the feed pump 61 is drilled in the cam shaft housing 2 and the hydraulic head 3. It is pumped to the injection control valve side fuel gallery 56 connected to the drain side of the injection control valve 2 through the formed oil passage or pipe, and is used for maintaining the pressure of the injection control valve side fuel gallery 56.
[0033]
Further, a fuel feed pump 60 is attached to one side surface of the camshaft housing 2 and is driven by the rotation of the camshaft 4 to pump fuel. The bevel gear 60a fixed to the drive shaft 60b of the feed pump 60 meshes with the bevel gear 19 on the cam shaft 4, and the drive shaft 60b is rotationally driven by the rotation of the cam shaft 4. . The fuel stored in the fuel tank 70 by the feed pump 60 is pressure-fed to the supply pump-side fuel gallery 57 through an oil passage or piping formed in the camshaft housing 2 and the hydraulic head 3. Then, the fuel pressure-fed from the supply pump side fuel gallery 57 to the plunger chamber 7 a is led out to the pressure accumulating chamber 31 through the check valve 28.
[0034]
The injection control valve side fuel gallery 56 and the supply pump side fuel gallery 57 are formed independently so that the pressures of the gallery 57 and 56 can be held at different values. The supply pressure required for the supply pump-side fuel gallery 57 is a relatively low pressure of about 0.5 MPa. Therefore, an inexpensive large-capacity low-pressure pump such as a trochoid pump can be used as the feed pump 60. On the other hand, the injection control valve side fuel gallery 56 normally requires a relatively high pressure of 2 MPa or more in order to prevent the occurrence of cavitation and stabilize the injection, but the discharge amount of the feed pump 61 is smaller than that of the feed pump 60. Less than half is sufficient. Therefore, it is possible to use a relatively inexpensive small-capacity high-pressure pump as the feed pump 61.
[0035]
In this manner, the injection control valve side fuel gallery 56 and the supply pump side fuel gallery 57 are configured independently, and a plurality of relatively inexpensive feed pumps 60 and 61 are provided to inject fuel into the injection control valve side fuel gallery. 56 and the supply pump-side fuel gallery 57 are separately pumped so that the injection control valve-side fuel gallery 56 and the supply pump-side fuel gallery 57 communicate with each other, and both the gallery 56 and 57 are connected by one large-capacity high-pressure pump. Compared with the case where the comparatively high pressure of 2 MPa or more is maintained, it can be configured at a low cost.
[0036]
Further, as shown in FIG. 9, the injection control valve side fuel gallery 56 and the supply pump side fuel gallery 57 are made independent so that the respective pressures can be maintained at different values. The high pressure accumulating chamber 31 may be connected via a pressure reducing valve 58 so that the pressure of the injection control valve side fuel gallery 56 is held by the fuel guided from the pressure reducing valve 58. In this case, since the pressure in the pressure accumulating chamber 31 is used to hold the pressure of the injection control valve side fuel gallery 56, a pump for holding the pressure of the injection control valve side fuel gallery 56 is not required and can be configured at low cost.
[0037]
In order to stabilize the next injection, injection control is performed on the oil passage 77 between the discharge valve 18 and the distribution shaft 9 or the oil passages 77 and 78 between the injection nozzle 29 and the distribution shaft 9 in a predetermined period after the end of injection. A so-called pressure equalizing stroke is provided in which the valve-side fuel gallery 56 is communicated and released, and the pressure after the injection between the injection nozzle 29 and the distribution shaft 9 is the same as that of the stable fuel gallery. In this way, by connecting the oil passages 77 and 78 to the injection control valve-side fuel gallery 56, the space between the injection nozzle 29 and the distribution shaft 9 can be maintained at a relatively high and stable pressure of 2 MPa or more, and the injection is completed. It prevents the occurrence of later cavitation and stabilizes the injection. In particular, in the case of an accumulator-type distribution type pump having a structure in which the injection nozzle 29 is directly connected to the distribution shaft 9 without passing through the equal pressure valve after the injection is completed, the residual pressure in the high pressure pipe can be maintained in the pressure equalization stroke. Therefore, it is effective for stabilizing the injection.
[0038]
Next, the structure of the safety valve 24 will be described. Conventionally, in an accumulator-type distribution type fuel injection pump, in order to perform high-pressure fuel injection, high accuracy is required for processing and operation of each component member, and thus there is a problem that the manufacturing cost increases. That is, as shown in FIG. 12, in the safety valve 24 ′ that is generally used to prevent the pressure in the pressure accumulating chamber 31 from rising abnormally, it is pressed toward the pressure accumulating chamber 31 by the biasing member 46. The valve body 52 is formed integrally with a sliding restricting portion 52b for restricting the sliding of the valve body 52 and a closing portion 52a for closing the opening, and the sliding portion 52a and the closing portion 52a are slid to increase the accuracy of the safety valve 24 ′. High concentricity is required for the movement restricting portion 52b, and machining accuracy is required.
[0039]
The safety valve 24 is used to prevent the pressure accumulation chamber 31 from becoming higher than the set pressure by opening the safety valve 24 and waste oil when the pressure in the pressure accumulation chamber 31 becomes higher than the set pressure. As shown in FIGS. 6 and 10, the safety valve 24 includes a cylinder 45 in which a part thereof is inserted into a fitting insertion hole 3 d formed in the hydraulic head 3 so as to close the pressure accumulating chamber 31, and the cylinder 45. The valve body 59 is slidably inserted in the formed safety valve chamber 55, and the valve body 59 is pressed toward the pressure accumulation chamber 31 by the biasing member 46.
[0040]
As shown in FIG. 11, the valve element 59 closes the sliding restricting member 47 for satisfactorily sliding in the safety valve chamber 55 and the valve portion 45 a of the cylinder 45 communicating with the cylinder 45 and the pressure accumulating chamber 31. Therefore, the closing member 48 is composed of two members formed separately from each other. The sliding restricting member 47 is opposed to the inner wall of the safety valve chamber 55 to restrict the sliding of the valve body 59, and the pressing portion 47a is inserted into the closing member 48 to press the closing member 48. Are integrally formed. The outer diameter of the guide portion 47b is formed slightly smaller than the inner diameter of the safety valve chamber 55, and the sliding regulating member 47 can slide in the safety valve chamber 55 through the gap between the guide portion 47b and the inner wall of the safety valve chamber 55. It is the smallest. With this configuration, the fuel in the safety valve chamber 55 on the biasing member 46 side is compressed with respect to the sliding restricting member 47 when the valve body 59 slides when the safety valve 24 is opened, whereby the valve body 59 is compressed. The seating impact force on the seat portion 45c of the valve body 59 is reduced by reducing the valve opening speed of the valve body 59 due to a decrease in the sliding stroke of the valve body 59. Since the amount of wear of the seat portion 45c is reduced, the durability of the safety valve 24 is improved.
[0041]
On the other hand, the closing member 48 is pressed against the seat portion 45c of the cylinder 45 to close the valve portion 45a, and an insertion portion in which an insertion hole 48Ba for inserting the pressing portion 47a of the sliding restriction member 47 is formed. 48B is integrally formed, and the inner diameter of the insertion hole 48Ba is configured to be somewhat larger than the outer diameter of the pressing portion 47a of the sliding restricting member 47 so that the insertion hole 48B is somewhat between the pressing portion 47a. A gap is generated.
[0042]
As described above, the valve body 59 is constituted by the two members of the sliding restricting member 47 and the closing member 48, so that the pressing portion 47a of the sliding restricting member 47 is accurately and coaxially inserted into the insertion hole 48Ba of the closing member 48. Even if not, the closing member 48 can close the valve portion 45a of the cylinder 45 satisfactorily. Accordingly, even if the coaxiality of the pressing portion 47a of the sliding restricting member 47 and the insertion hole 48Ba of the closing member 48 is slightly deviated depending on the processing accuracy, a good function as the valve body 59 is maintained. Contributes to cost reduction.
[0043]
An annular gallery 54 is provided on the outer periphery of the cylinder 45, and the safety valve chamber 55 and the annular gallery 54 are passed through an oil passage 45 b provided in the cylinder 45. Further, the annular gallery 54 and the cylinder 45 The hydraulic head 3 is formed with an oil passage 49 a that connects the low-pressure side gallery 49 connected to the low-pressure side oil passage 32. That is, the safety valve chamber 55 and the low-pressure side gallery 49 are passed through the annular gallery 54, and the waste oil from the high pressure accumulating chamber 31 passes from the safety valve chamber 55 through the low-pressure side gallery 49 to the low-pressure side oil passage 32. Sent. Thus, by forming the drain oil passage of the safety valve chamber 55 without providing external piping, it is possible to prevent leakage of liquid at the mounting portion of the external piping.
[0044]
【The invention's effect】
Since the present invention is configured as described above, the following effects can be obtained.
[0045]
As in claim 1, in a pressure-accumulation-type distributed fuel injection pump that distributes and supplies high-pressure fuel accumulated in the pressure accumulation chamber (31) to each cylinder by a distribution shaft (9), the plunger (7) for pressure-feeding the fuel A supply pump side fuel gallery (57) connected to the plunger chamber (7a) and an injection control valve side fuel gallery (56) connected to the injection control valve (26) chamber are configured independently, and each supply pump side fuel gallery ( 57) and the injection control valve side fuel gallery (56) are different from each other because the fuel is pumped from the feed pump side feed pump (60) and the injection control valve side feed pump (61) which are different feed pumps. The necessary pressure and amount of fuel from the feed pump are pumped to each fuel gallery, compared to when a single high-pressure, large-capacity pump is used. It is possible to reduce the cost of the pump.
[0049]
According to a second aspect of the present invention, there is provided an accumulator distribution type fuel injection pump for distributing and supplying high pressure fuel accumulated in the accumulator chamber (31) to each cylinder by a distribution shaft (9). A supply pump side fuel gallery (57) connected to the plunger chamber (7a) and an injection control valve side fuel gallery (56) connected to the injection control valve (26) chamber are configured independently, and the supply pump side fuel gallery ( 57), the fuel is pumped from the supply pump side feed pump (60), and the fuel stored in the pressure accumulating chamber (31) is supplied to the injection control valve side fuel gallery (56) by the pressure reducing valve (58). since supplies through, it can be made unnecessary feed pump, the cost can be reduced.
[0050]
According to a third aspect of the present invention, in the accumulator-type distributed fuel injection pump according to the first or second aspect, an oil passage (77) between the discharge valve (18) and the distribution shaft (9) is provided in a predetermined period after the end of injection. ) Or the oil passage (77, 78) between the injection nozzle (29) and the distribution shaft (9) communicates with the fuel gallery (56) on the injection control valve side, so that there is no residual pressure in the fuel injection rod. The injection can be stabilized by blocking.
[Brief description of the drawings]
FIG. 1 is a schematic view showing a state at the time of fuel injection in a fuel injection pump according to the present invention.
FIG. 2 is a schematic view showing a state when no fuel is injected in the fuel injection pump.
FIG. 3 is a cross-sectional view showing a fuel injection pump.
FIG. 4 is also a plan view.
FIG. 5 is a cross-sectional view showing an injection control valve.
FIG. 6 is a sectional view showing a pressure accumulating chamber of the fuel injection pump.
FIG. 7 is a cross-sectional view showing an injection control valve.
FIG. 8 is a view showing a fuel pipe.
FIG. 9 is a diagram showing another configuration example of the fuel pipe.
FIG. 10 is a cross-sectional view showing a safety valve.
FIG. 11 is a cross-sectional view showing a valve body of a safety valve.
FIG. 12 is a cross-sectional view showing the structure of a conventional safety valve.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Fuel injection pump 3 Hydraulic head 7 Plunger 9 Distribution shaft 24 Safety valve 26 Injection control valve 27 Pressure control valve 29 Injection nozzle 31 Accumulation chamber 45 Cylinder 47 Sliding regulation member 48 Closure member 49 Low-pressure side gallery 54 Annular gallery 56 Injection control valve Side fuel gallery 57 Supply pump side fuel gallery 59 Valve body 60 (Supply pump side) Feed pump 61 (Injection control valve side) Feed pump

Claims (3)

In a pressure-accumulation-type distributed fuel injection pump that distributes and supplies high-pressure fuel accumulated in the pressure accumulation chamber (31) to each cylinder by a distribution shaft (9), the plunger chamber (7a) of the plunger (7) that pumps fuel is supplied to The connected supply pump side fuel gallery (57) and the injection control valve side fuel gallery (56) connected to the chamber are independently configured, and each supply pump side fuel gallery (57) and the injection control valve are configured. The accumulator-type distributed fuel injection is characterized in that fuel is pumped from a feed pump side feed pump (60) and an injection control valve side feed pump (61) which are different feed pumps to the side fuel gallery (56). pump. In a pressure-accumulation-type distributed fuel injection pump that distributes and supplies high-pressure fuel accumulated in the pressure accumulation chamber (31) to each cylinder by a distribution shaft (9), the plunger chamber (7a) of the plunger (7) that pumps fuel is supplied to The connected supply pump side fuel gallery (57) and the injection control valve side fuel gallery (56) connected to the chamber of the injection control valve (26) are configured independently, and the supply pump side fuel gallery (57) Fuel is pumped from a pump-side feed pump (60), and fuel stored in the pressure accumulating chamber (31) is supplied to the injection control valve-side fuel gallery (56) via a pressure reducing valve (58). An accumulator-type distribution type fuel injection pump. The pressure accumulation type distribution type fuel injection pump according to claim 1 or 2, wherein an oil passage (77) between the discharge valve (18) and the distribution shaft (9) or an injection nozzle is provided for a predetermined period after the end of injection. An accumulator-type distribution type fuel injection pump characterized in that an oil passage (77, 78) between (29) and a distribution shaft (9) communicates with an injection control valve side fuel gallery (56) .

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