JP2006083821A - Fuel injection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel injection device including a supply pump having an intake control valve of new constitution in the intake metering type fuel injection device. <P>SOLUTION: This fuel injection device 1A includes: a supply pump 2A; a common rail 3 storing fuel forced-fed from the supply pump 2A; and an injector connected to the common rail 3 to inject fuel. The common rail 3 is provided with a metering control valve 3B, and the supply pump 2A is provided with an intake control valve 20, whereby the fuel pressure in the common rail is controlled by controlling the quantity of fuel leaking from the metering control valve 3B, and the intake control valve 20 is controlled by leaked fuel to control the intake of fuel in a fuel pressurizing chamber 2b of the supply pump 2A. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a structure of a fuel injection device for a diesel engine comprising a supply pump, a common rail that stores fuel pumped from the supply pump, and an injector that is connected to the common rail and injects fuel. The present invention relates to a configuration of a supply pump that can adjust the amount of fuel sucked into a pressurized chamber.

2. Description of the Related Art Conventionally, a fuel injection apparatus including a supply pump, a common rail that stores fuel pumped from the supply pump, and an injector that is connected to the common rail and injects fuel has been known (see, for example, Patent Document 1). .)
In addition, as the supply pump, a so-called intake metering type that can adjust the amount of fuel sucked into the pressurized chamber is well known. The adjustment of the intake amount is performed by controlling a solenoid valve provided in the intake amount control valve with a controller.
The common rail is provided with a pressure sensor for detecting the fuel pressure and an electromagnetic valve for leaking the fuel, so that the fuel pressure in the common rail is maintained constant or the pressure is reduced during deceleration. Is going to be done.
JP 2001-82230 A

However, in the configuration of the conventional intake metering type fuel injection device, there is a problem that the solenoid valve of the intake amount control valve leads to high costs, and software development and adjustment for the control are required. .
On the other hand, as disclosed in Patent Document 1 described above, in the common rail, fuel is leaked to control the fuel pressure, and this leaked fuel is used to suck the fuel into the pressurizing chamber. I thought whether the amount could be controlled.
The present invention proposes a fuel injection device including a supply pump including a suction amount control valve having a novel configuration in an intake metering type fuel injection device.
In addition, a configuration is also proposed in which a control rack for fuel metering is controlled to perform a function equivalent to the pressure control in the intake metering common rail.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

  That is, as described in claim 1, a fuel injection device comprising a supply pump, a common rail that stores fuel pumped from the supply pump, and an injector that is connected to the common rail and injects fuel, The common rail is provided with a pressure regulating control valve, the supply pump is provided with an intake amount control valve, and the amount of fuel leaked from the pressure regulating control valve is controlled to control the fuel pressure in the common rail. The intake amount control valve is controlled by fuel to control the intake amount of fuel in the pressurizing chamber of the supply pump.

  According to a second aspect of the present invention, an accumulator for storing leaked fuel is provided in a first oil passage that communicates the pressure regulating control valve and the suction amount control valve, and the pressurizing chamber and the suction chamber are provided. The second oil passage communicating with the quantity control valve is configured to communicate with the first oil passage via the third oil passage.

  Further, as described in claim 3, a fuel injection device comprising a supply pump, a common rail that stores fuel pumped from the supply pump, and an injector that is connected to the common rail and injects fuel, The common rail is provided with a pressure control valve, the fuel pump is provided with a fuel metering control rack, and the fuel pressure in the common rail is controlled by controlling the amount of fuel leaked from the pressure control valve. The control rack is controlled by the leaked fuel to control the amount of fuel discharged from the fuel pressurizing chamber of the supply pump to the common rail.

  According to a fourth aspect of the present invention, the hydraulic head of the supply pump includes a plunger, an inlet valve mechanism, an outlet valve mechanism, and a high-pressure pipe joint in order from the side closer to the cam that slides the plunger. The inlet valve mechanism, the outlet valve mechanism, and the high-pressure fitting are arranged on the same axis as the central axis of the plunger.

  According to a fifth aspect of the present invention, the supply pump is configured such that a plunger drop-off prevention device is provided outside the plunger sliding portion.

  As effects of the present invention, the following effects can be obtained.

That is, according to the first aspect of the present invention, the intake control valve for controlling the fuel pressure in the common rail is controlled to control the intake amount control valve to adjust the intake amount of fuel in the pressurizing chamber. We can measure and control the fuel pressure in the common rail. In other words, the amount of fuel sucked into the pressurizing chamber can be controlled using the leaked fuel.
In this configuration, since the only solenoid valve to be controlled is the pressure regulating control valve, compared with the conventional configuration in which the suction amount control valve is an electromagnetic valve, the device configuration is simplified, the cost is reduced, and the control is performed. Benefits such as simplification are obtained.

  In the invention according to claim 2, the fuel leaked from the common rail can be directly supplied to the pressurizing chamber through the oil passage, and the fuel temperature in the fuel tank rises by returning the fuel. Can be eliminated.

  According to the third aspect of the present invention, the amount of fuel supplied to the common rail can be adjusted without providing an intake amount control valve, whereby the pressure in the common rail 3 can be controlled. In other words, the amount of fuel pumped from the pressurizing chamber can be controlled using the leaked fuel.

In the invention according to the fourth aspect, the volume from the pressurizing chamber to the high-pressure pipe joint can be made small, so that the loss of fuel pumping can be reduced and the entire apparatus can be made compact.
In addition, since the inlet valve mechanism and the outlet valve mechanism are configured separately, the high pressure seal surface (see FIG. 5) between the inlet valve mechanism and the plunger barrel, and the high pressure between the inlet valve mechanism and the outlet valve mechanism. The high-pressure seal surface between the seal surface and the outlet valve structure and the high-pressure fitting can be easily processed.

  According to the fifth aspect of the present invention, it is possible to prevent the plunger from dropping off from the sliding portion of the plunger during the operation, and the attachment of the supply pump to the engine is facilitated.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a configuration of a first embodiment of a fuel injection device according to the present invention.
The fuel injection device 1A includes a supply pump 2A, a common rail 3, injectors 4, 4,.
The fuel pumped from the fuel tank 5 by the feed pump 6 is supplied into the supply pump 2A through the pipe 6A. The pipe 6A is provided with a bypass pipe 6b that communicates the discharge side and the suction side of the feed pump 6, and the fuel pressure supplied to the supply pump 2A is controlled by the pressure regulating valve 6c provided in the bypass pipe 6b. Adjusted. The pipe 6A is provided with a temperature sensor 6a so that the fuel temperature can be measured by the temperature sensor 6a.
The supply pump 2A is provided with a suction amount control valve 20, and the fuel supplied from the pipe 6A is supplied to the pressurizing chamber of the plunger 2a via the suction amount control valve 20, the oil passage 24c, and the check valve 2d. 2b. The intake amount control valve 20 controls the intake amount of fuel into the pressurizing chamber 2b.
The fuel pressurized by the plunger 2a in the pressurizing chamber 2b is discharged into the common rail 3 through the check valve 2c.
The fuel in the common rail 3 is supplied to the injectors 4..., And the fuel is injected by the injectors 4, 4.

The common rail 3 is provided with a pressure sensor 3A for detecting the fuel pressure in the common rail 3, and a pressure regulating control valve 3B for controlling the fuel pressure. When the pressure control valve 3B is opened, the fuel in the common rail 3 leaks, and the pressure in the common rail 3 is reduced.
The pressure sensor 3 </ b> A and the pressure control valve 3 </ b> B are connected to the controller 10. The controller 10 performs opening / closing control of the pressure regulating control valve 3B based on the detected value of the fuel pressure by the pressure sensor 3A, and sets the fuel pressure in the common rail 3 to a predetermined value.

As shown in FIG. 2, the pressure regulating control valve 3B includes a valve body 3b that closes the fuel leak port 3a of the common rail 3, an armature 3c that holds the valve body 3b, and an armature 3c that biases the fuel leak port 3a toward the fuel leak port 3a. And a solenoid 3e that applies a suction force in the same direction as the urging force of the spring 3d to the armature 3c.
The spring 3d urges the armature 3c to the left in the drawing. When the solenoid 3e is not energized, the fuel leak port 3a is closed by the urging force of the spring 3d. The spring force of the spring 3d is set so that the pressure in the common rail 3 becomes a value capable of fuel injection so that fuel injection can be performed even when the solenoid 3e cannot be energized due to failure or the like. Yes.
On the other hand, when the solenoid 3e is energized, a biasing force in the same direction as the spring force acts on the armature 3c in accordance with the magnitude of the exciting current, and the pressure at which the fuel leak port 3a opens is increased. Therefore, the pressure in the common rail 3 can be set to a predetermined value by controlling the magnitude of the excitation current.

As shown in FIG. 2, the suction amount control valve 20 includes a cylinder chamber 21, a piston 22 that slides in the cylinder chamber 21, a spring 23 that biases the piston 22 in one side direction, and the like. It is configured.
The inside of the cylinder chamber 21 is divided by the piston 22 into two chambers, a fuel supply chamber 21a and a control chamber 21b. The small diameter portion 22a of the piston 22 is disposed on the fuel supply chamber 21a side, and the large diameter portion 22c is disposed on the control chamber 21b side.
Further, between the small-diameter portion 22a and the large-diameter portion 22c of the piston 22, a frustoconical intermediate portion 22b is formed, and a throttle is formed between the intermediate portion 22b and a port 25c described later.
The spring 23 is sandwiched between the small diameter portion 22a of the piston 22 and the wall surface of the fuel supply chamber 21a.

Further, the fuel supply chamber 21a is provided with a port 25a, and the fuel discharged from the feed pump 6 flows into the fuel supply chamber 21a from the port 25a through the pipe 6A and the oil passage 24a. Is done.
The fuel supply chamber 21a is provided with a port 25b through which the fuel in the fuel supply chamber 21a is leaked to the fuel tank 5 through the oil passage 24b, the throttle 27b, and the pipe 7A. It is said. The leaked fuel is limited by the throttle 27b so that the fuel pressure in the fuel supply chamber 21a is properly maintained.
The fuel supply chamber 21a is provided with a port 25c, and the fuel in the fuel supply chamber 21a is sucked into the pressurizing chamber 2b from the port 25c through the oil passage 24c.

The control chamber 21b is provided with a port 25e, and the fuel leaked from the fuel leak port 3a of the common rail 3 enters the control chamber 21b from the port 25e via the pipe 9A and the oil passage 24e. Inflow.
The control chamber 21b is provided with a port 25d. From the port 25d, the fuel in the control chamber 21b is leaked to the fuel tank 5 through the oil passage 24d, the throttle 27d, and the pipe 8A. . The leaked fuel is limited by the throttle 27d so that the fuel pressure in the control chamber 21b is properly maintained.

Further, the fuel pressure in the control chamber 21b acts on the end face of the large diameter portion 22c of the piston 22 and urges the piston 22 rightward in FIG.
Further, the spring 23 in the fuel supply chamber 21a acts on the end face of the small diameter portion 22a of the piston 22 to urge the piston 22 leftward in FIG.

Then, the fuel pressure in the control chamber 21b is adjusted, and the piston 22 is moved in the left-right direction by changing the urging force of the piston 22 in the right direction.
The fuel pressure in the control chamber 21b is adjusted by adjusting the amount of inflow of fuel from the port 25e, that is, adjusting the amount of leak from the pressure control valve 3B.
Thus, by changing the position of the piston 22 in the left-right direction, the position of the large-diameter portion 22c of the piston 22 with respect to the port 25c is changed, and the opening degree of the port 25c is changed. That is, when the piston 22 moves to the left side in FIG. 2, the opening degree (opening area) of the port 25c increases, and when the piston 22 moves to the right side in FIG. 2, the opening degree (opening area) of the port 25c. ) Has been reduced.
The controller 10 is configured as described above, and the controller 10 adjusts the opening degree of the pressure regulating control valve 3B to control the leak amount of the common rail 3, thereby adjusting the opening degree of the port 25c of the suction amount control valve 20. The amount of fuel flowing out from the port 25c is adjusted, and the amount of fuel sucked into the pressurizing chamber 2b is adjusted.

FIG. 3 shows (a) when the fuel pressure in the common rail 3 is kept at a set pressure, (b) when the fuel pressure in the common rail 3 is increased at the time of engine start, and (c) the fuel in the common rail 3 at the time of sudden deceleration. The position of the piston 22 of the suction amount control valve 20 in each of the cases where the pressure is lowered is shown.
As shown in FIG. 3A, when the fuel pressure in the common rail 3 is kept at the set pressure, the controller 10 controls the pressure regulating control valve 3B to adjust the leak amount from the fuel leak port 3a. The leaked fuel flows into the control chamber 21b of the intake amount control valve 20, and thereby the left and right positions of the piston 22 are set. The opening of the port 25c is set by setting the left and right positions of the piston 22, and the amount of fuel supplied to the pressurizing chamber 2b via the oil passage 24c and the check valve 2d is determined. In the example of FIG. 3A, the opening area of the port 25c is set to about half of the fully open state.
Further, when pressure fluctuation occurs in the common rail 3, the controller 10 adjusts the opening of the pressure regulating control valve 3B based on the detected value of the pressure sensor 3A, thereby the fuel in the pressurizing chamber 2b. The intake amount is controlled, and the fuel pressure in the common rail 3 is adjusted to the set pressure.
Further, for example, when the pressure in the common rail 3 is lower than the set pressure, the controller 10 decreases the opening degree of the pressure regulating control valve 3B and decreases the amount of fuel leakage. As a result, the fuel pressure in the control chamber 21b of the intake amount control valve 20 is reduced, the piston 22 moves to the left in the figure, and the opening degree of the port 25c is increased. Then, the fuel suction amount in the pressurizing chamber 2b is increased, and the fuel discharge amount to the common rail 3 is increased, whereby the fuel pressure in the common rail 3 is increased to the set pressure.

Further, as shown in FIG. 3B, when increasing the fuel pressure in the common rail 3 at the time of starting the engine, the controller 10 does not energize the solenoid of the pressure regulating control valve 3B, and the fuel leak port 3a. Will be closed. As a result, the fuel pressure in the control chamber 21b of the intake amount control valve 20 is set low, the piston 22 moves leftward in the figure, and the opening of the port 25c is set wide. In the example of FIG. 3B, the port 25c is in a state where it is set to be fully open.
As a result, the amount of fuel sucked into the pressurizing chamber 2b is increased and the leakage of fuel from the common rail 3 is restricted, so that the fuel pressure in the common rail 3 can be reduced to the set pressure in a shorter time when starting the engine. The voltage can be boosted.

Further, as shown in FIG. 3C, when the fuel pressure in the common rail 3 is lowered during sudden deceleration, the controller 10 sets the excitation current of the solenoid of the pressure regulating control valve 3B to be high, and the fuel leak port 3a. Increase the opening. Thereby, the fuel pressure in the control chamber 21b of the intake amount control valve 20 is set high, the piston 22 moves rightward in the drawing, and the opening degree of the port 25c is set narrow. In the example of FIG. 3C, the port 25c is in a state where it is set to be substantially fully closed.
As a result, the amount of fuel sucked into the pressurizing chamber 2b is reduced and the amount of fuel leaked from the common rail 3 is increased, so that the fuel pressure in the common rail 3 can be lowered in a shorter time during sudden deceleration. it can.

As described above, the fuel injection device 1A includes the supply pump 2A, the common rail 3 that stores fuel pumped from the supply pump 2A, and the injector that is connected to the common rail 3 and injects fuel. The common rail 3 is provided with a pressure control valve 3B, the supply pump 2A is provided with a suction amount control valve 20, and the fuel pressure in the common rail 3 is controlled by controlling the amount of fuel leaked from the pressure control valve 3B. In addition to the control, the intake amount control valve 20 is controlled by the leaked fuel to control the intake amount of fuel in the pressurizing chamber 2b of the supply pump 2A.
Thus, by controlling the pressure control valve 3B, the intake amount control valve 20 can be controlled to adjust the fuel intake amount in the pressurizing chamber 2b, and the fuel pressure in the common rail 3 can be controlled.
In this configuration, since the only solenoid valve to be controlled is the pressure regulating control valve 3B, compared with the conventional configuration in which the suction amount control valve 20 is an electromagnetic valve, the device configuration is simplified, the cost is reduced, Advantages such as simplified control can be obtained. That is, conventionally, two solenoid valves are required for controlling the fuel pressure in the common rail 3, but in this proposal, the fuel pressure can be controlled by one solenoid valve.

Next, a configuration example of the supply pump when the above configuration is implemented will be described.
As shown in FIG. 4, a plunger barrel 41 is fitted in the hydraulic head 40, and a plunger 2 a is provided in the plunger barrel 41 so as to be slidable up and down. A spring receiver 42 is engaged with the lower portion of the plunger 2 a, and the spring receiver 42 is placed on the tappet 43. A cam 44 is arranged below the tappet 43. The tappet 43 is lifted by the cam 44, and the plunger 2a moves upward via the spring receiver 42, so that the fuel is fed in the pressurizing chamber 2b. Is to be done. Further, a spring 45 is sandwiched between the spring receiver 42 and the hydraulic head 40, and the spring receiver 42 and the plunger 2a are always urged downward, whereby the plunger 2a is moved downward and pressurized. A fuel suction stroke is performed in the chamber 2b. In the example shown in the figure, the plunger barrel 41 is configured separately from the hydraulic head 40. However, the sliding portion of the plunger 2a is formed on the hydraulic head 40 without providing the plunger barrel 41. It is good also as a structure.

The hydraulic head 40 is provided with a plunger 2a, an inlet valve mechanism 46, an outlet valve mechanism 47, and a high-pressure fitting 48 in order from the side closer to the cam 44 that slides the plunger 2a to the side farther from the cam 44. The inlet valve structure 46, the outlet valve structure 47, and the high-pressure fitting 48 are arranged on the same axis as the central axis of the plunger.
In the configuration of the present embodiment in which the plunger 2 a is slid in the vertical direction, an inlet valve mechanism 46 is disposed above the plunger 2 a, and an outlet valve mechanism 47 is disposed above the inlet valve mechanism 46. The high pressure pipe 48 is disposed above the outlet valve structure 47, and the plunger 2a, the inlet valve structure 46, the outlet valve structure 47, and the high pressure pipe 48 are arranged on the same axis as the central axis of the plunger 2a. It is assumed to be configured.
With this configuration, the volume from the pressurizing chamber 2b above the plunger 2a to the high-pressure pipe joint 48 can be reduced, so that the fuel pressure loss can be reduced and the entire apparatus can be made compact.
In addition, since the inlet valve mechanism 46 and the outlet valve mechanism 47 are configured separately, the high-pressure seal surface 49a (see FIG. 5) between the inlet valve mechanism 46 and the plunger barrel 41, the inlet valve mechanism 46, and the outlet. The high-pressure seal surface 49b between the valve structure 47 and the high-pressure seal surface 49c between the outlet valve structure 47 and the high-pressure fitting 48 can be easily processed.

As shown in FIG. 5, the inlet valve mechanism 46 includes a valve seat 46A, an inlet valve 46B for opening and closing an oil passage in the valve seat 46A, and the like. The valve seat 46 </ b> A is provided in the insertion hole 40 </ b> A of the hydraulic head 40 and forms a high-pressure seal surface 49 a with the upper surface of the plunger barrel 41. A plurality of oil passages 46a and 46a communicating with the pressurizing chamber 2b of the plunger barrel 41 are formed in the valve seat 46A in the vertical direction.
A seat portion 46b is formed inside the oil passages 46a and 46a, a valve seat surface 46s is formed above the seat portion 46b, and an inlet valve 46B is seated on the valve seat surface 46s.
The seat portion 46b is provided with an oil passage 46d opened to the inlet valve 46B side, and the opening portion of the oil passage 46d is opened and closed by the inlet valve 46B.
An annular oil chamber 46C is formed between the valve seat 46A and the insertion hole 40A of the hydraulic head 40, and the oil chamber 46C and the oil passage 46d are communicated by oil passages 46f and 46f. ing.

The valve seat 46A is formed with a sliding hole 46D of the inlet valve 46B in the vertical direction, and a large-diameter hole 46E is formed below the sliding hole 46D. The large diameter hole 46E communicates with the oil passages 46a and 46a.
The inlet valve 46B is formed with an oil passage 46g whose top is opened. The inlet valve 46B is formed with oil passages 46h and 46h that allow the lower portion of the oil passage 46g to communicate with the large-diameter hole 46E.
Further, in the inlet valve 46B, a spring accommodation hole 46k is formed above the oil passage 46g, and the spring 46m is accommodated. The upper end of the spring 46m is in contact with the lower surface of the valve seat 47A of the outlet valve mechanism 47.

The outlet valve mechanism 47 includes a valve seat 47A, the inlet valve mechanism 46, and an outlet valve 47B that opens and closes an oil passage 47a between the high-pressure pipe joint 48.
An oil passage 47a is formed in the valve seat 47A in the vertical direction, and the oil passage 47a communicates with the spring accommodating hole 46k of the inlet valve 46B and the oil passage 46g. A space between the oil passage 47a and the spring accommodation hole 46k is sealed by a high pressure seal surface 49b. The oil passage 47a is formed in a Y shape in sectional view to form a valve seat surface 47s, and a spherical outlet valve 47B is abutted against the valve seat surface 47s, and the oil passage 47a is closed.

A discharge oil passage 48A is formed in the high-pressure pipe joint 48 in the vertical direction, and a plurality of oil passages 48a and 48a communicating with the oil passage 47a of the valve seat 47A are provided vertically below the discharge oil passage 48A. Is formed in the direction. On the inner side of the oil passages 48a and 48a, a contact portion 48b is formed to contact the outlet valve 47B when the outlet valve 47B is raised.
The oil passages 48a and 48a and the oil passage 47a are sealed by a high-pressure seal surface 49c.

  Further, in the hydraulic head 40, a suction port 40a is provided at a position where the oil chamber 46C is formed, and fuel is introduced from the suction port 40a. The suction port 40a communicates with a fuel gallery 40c formed in the hydraulic head 40 via an oil passage 40b.

In the above configuration, during the fuel pressure-feeding stroke, as shown in FIG. 5, the fuel in the pressurizing chamber 2b is compressed by raising the plunger 2a. The compressed high-pressure fuel flows into the large-diameter hole 46E from the oil passages 46a and 46a, and further flows into the oil passages 46h and 46g of the inlet valve 46B to push the inlet valve 46B downward. As a result, the valve seat surface 46s is closed by the inlet valve 46B. The high-pressure fuel flows into the oil passage 47a through the oil passage 46g and the spring accommodating hole 46k, pushes up the outlet valve 47B, and flows into the oil passages 48a and 48a and the discharge oil passage 48A. Thus, the fuel pressure-fed to the discharge oil passage 48A is supplied to the common rail 3 (not shown).
On the other hand, during the fuel intake stroke, as shown in FIG. 6, the fuel in the oil passages 46g and 46h of the inlet valve 46B, the large-diameter hole 46E, and the oil passages 46a and 46a of the valve seat 46A is caused by the lowering of the plunger 2a. Is sucked into the pressurizing chamber 2b. Further, the fuel in the oil chamber 46C flows into the oil passage 46d through the oil passages 46f and 46f, pushes up the inlet valve 46B, flows into the large-diameter hole 46E, and is pressurized through the oil passages 46a and 46a. Inhaled into chamber 2b. At this time, the valve seat surface 47s is closed by the outlet valve 47B by the high-pressure fuel in the discharge oil passage 48A. In this manner, fuel is sucked in the pressurizing chamber 2b.

Next, a configuration for preventing the plunger 2a from falling off will be described.
At the time of the mechanism, as shown in FIG. 7, a spring receiver 42 is attached to the lower end of the plunger 2 a, and a spring 45 is sandwiched between the spring receiver 42 and the hydraulic head 40. In this case, since the spring receiver 42 is urged away from the hydraulic head 40 by the urging force of the spring 45, the plunger 2a may fall off the plunger sliding portion.
Therefore, as shown in FIGS. 4, 7, and 8, on the side outside the plunger sliding portion (plunger barrel 41) and close to the cam 44 that slides the plunger 2 a, the plunger 2 a is prevented from falling off 61. The stopper 2 is locked to the truncated cone-shaped portion 2f on the cam 44 side of the plunger 2a, so that the plunger 2a can be prevented from dropping from the plunger sliding portion. As a result, the mechanism can be improved.
In the example shown in the figure, the plunger barrel 41 is configured separately from the hydraulic head 40. However, the sliding portion of the plunger 2a is formed on the hydraulic head 40 without providing the plunger barrel 41. It is good also as a structure. In this case, the drop prevention tool 61 is attached to the hydraulic head 40.

The drop-off prevention tool 61 is formed by bending a plate-like member into a concave shape when viewed from the side, and the standing portions 61 a and 61 a on both sides thereof are provided with locking holes 41 a and 41 a provided in the plunger barrel 41. Locking portions 61b and 61b to be engaged are provided. In the configuration example of FIG. 8A, the standing portions 61a and 61a are configured on a substantially straight wall surface in a plan view, and in the configuration example in FIG. 8B, the standing portions 61a and 61a are omitted in a plan view. The example comprised on the circular arc-shaped wall surface is shown.
Further, a substantially U-shaped plunger insertion hole 61d is provided in the horizontal portion 61c of the drop prevention tool 61, and the bent portion of the plunger insertion hole 61d is connected to the plunger 2a with respect to the small diameter portion 2g of the plunger 2a. It is possible to approach from the direction orthogonal to the axis of Thereby, the width | variety of the plunger insertion hole 61d can be comprised smaller than the diameter of the engaging part 2h with the spring receiver 42 of the plunger 2a.
With the above configuration, when the plunger 2a is about to fall off, the truncated cone-shaped portion 2f is locked to the plunger insertion hole 61d, and the plunger 2a is prevented from dropping off.

FIG. 9 shows the configuration of a second embodiment of the fuel injection device according to the present invention.
In the present embodiment, the first oil passage (pipe 9A) that communicates the pressure regulating control valve 3B and the control chamber 21b of the intake amount control valve 20 with the same basic configuration as that of the first embodiment shown in FIG. ) Is provided with an accumulator 62 for storing leaked fuel.
According to this configuration, even when there is no leak from the fuel leak port 3a of the common rail 3, the fuel pressure in the control chamber 21b is secured by the fuel stored in the accumulator 62. Thus, the spring 23 can be maintained at a fixed position against the urging force of the spring 23.
A safety valve 9c is provided in the pipe 9B that connects the pipe 9A and the fuel tank 5, and when the pressure in the pipe 9A becomes abnormally high, fuel can be drained through the safety valve 9c. I have to.

FIG. 10 shows a configuration of a third embodiment of the fuel injection device according to the present invention.
In the present embodiment, the second oil passage 24c that communicates the pressurizing chamber 2b and the suction amount control valve 20 with the same basic configuration as the first embodiment (FIG. 1) and the second embodiment (FIG. 9) is provided. The first oil passage (pipe 9A) communicates with the second oil passage 24s.
According to this configuration, the fuel leaked from the common rail 3 can be supplied directly to the pressurizing chamber 2b via the oil passage 24s. 9 can be omitted, and the return of the leaked fuel to the fuel tank 5 can be eliminated, and the return of the fuel in the fuel tank 5 can be eliminated. The fuel temperature will not rise.
The oil passage 24s is provided with a throttle 24u, and the fuel is decompressed and joined to the oil passage 24c.

FIG. 11 shows the configuration of a fourth embodiment of the fuel injection device according to the present invention.
In the present embodiment, the amount of fuel discharged from the pressurizing chamber 2b to the common rail 3 is controlled by operating the fuel metering control rack 71 with the pressure of the fuel leaked from the pressure regulating control valve 3B. The fuel pressure in the common rail 3 is controlled.
That is, the fuel injection device 1D includes a supply pump 2B, a common rail 3 that stores fuel pumped from the supply pump 2B, and an injector that is connected to the common rail 3 and injects fuel. Is provided with a pressure regulating control valve 3B, and the supply pump 2B is provided with a fuel metering control rack 71, and the fuel pressure in the common rail 3 is controlled by controlling the amount of fuel leaked from the pressure regulating control valve 3B. In addition to the control, the control rack 71 is controlled by the leaked fuel, and the amount of fuel discharged from the fuel pressurizing chamber 2b of the supply pump 2B to the common rail 3 is controlled.

The plunger 2a is provided with an upper lead 2m.
The plunger 2a is rotated by the control rack 71, and the fuel intake port 2p of the pressurizing chamber 2b is closed by changing the positional relationship between the upper lead 2m and the fuel intake port 2p of the pressurizing chamber 2b. The timing can be set. For example, if the timing for closing the fuel suction port 2p is set to be earlier, the overflow of the fuel from the fuel suction port 2p during the fuel pumping is reduced, and the fuel pumping amount to the common rail 3 is increased.
One end of the control rack 71 is inserted into the cylinder 70, and the insertion end receives the fuel pressure in the oil chamber 72 and is urged to the left in the figure, while the other end is outside the cylinder 70. And is urged rightward in the figure by a spring 73. Further, the fuel leaking from the common rail 3 flows into the oil chamber 72 through the pressure control valve 3B.

In the above configuration, when the fuel pressure in the oil chamber 72 is increased by the control of the pressure regulating control valve 3B, the control rack 71 is moved to the left in the drawing, and the rotation angle position of the plunger 2a determines the fuel pumping amount. Set to a position to decrease.
On the other hand, when the fuel pressure in the oil chamber 72 is low, the control rack 71 is moved rightward in the drawing by the urging force of the spring 73, and the rotation angle position of the plunger 2a is set to a position where the fuel pumping amount is increased. The
As described above, by controlling the control rack 71 using the fuel leaked from the common rail 3, it is possible to adjust the fuel supply amount to the common rail 3 without providing the intake amount control valve 20. Thus, the pressure in the common rail 3 can be controlled.

1 is a system configuration diagram of a fuel injection device according to Embodiment 1. FIG. The figure shown about the structure of a suction amount control valve. (A) is a figure showing the position of the piston of the intake amount control valve when the fuel pressure in the common rail is kept at the set pressure. FIG. 6B is a diagram showing the position of the piston of the intake amount control valve when the fuel pressure in the common rail is increased at the time of engine start. (C) is a figure showing the position of the piston of the intake amount control valve when the fuel pressure in the common rail is lowered during sudden deceleration. The figure shown about the structure of a supply pump. The figure shown about the structure of the inlet valve structure in a pumping stroke, and an outlet valve mechanism. The figure shown about the structure of the inlet valve structure in an intake stroke, and an outlet valve mechanism. The figure which shows the state by which drop-off of a plunger is controlled by a drop-off prevention tool. (A) is a top view of the fall prevention tool which comprised the standing part in the planar view substantially linear wall surface. (B) is a plan view of a drop-off prevention device in which the standing portion is configured on a substantially arc-shaped wall surface in a plan view. The system block diagram of the fuel-injection apparatus of Example 2. FIG. The system block diagram of the fuel-injection apparatus of Example 3. FIG. The system block diagram of the fuel-injection apparatus of Example 4. FIG.

Explanation of symbols

1A Fuel injection device 2A Supply pump 3 Common rail 3B Pressure control valve 20 Suction amount control valve

Claims (5)

  A fuel injection device comprising a supply pump, a common rail that stores fuel pumped from the supply pump, and an injector that is connected to the common rail and injects fuel, wherein the common rail is provided with a pressure control valve. The supply pump is provided with a suction amount control valve, and the fuel pressure in the common rail is controlled by controlling the amount of fuel leaked from the pressure control valve, and the suction amount control valve is controlled by the leaked fuel. A fuel injection device configured to control the amount of fuel sucked into the pressurization chamber of the supply pump.   An accumulator for storing leaked fuel is provided in a first oil passage communicating with the pressure control valve and the intake amount control valve, and a second oil communicating with the pressurizing chamber and the intake amount control valve. 2. The fuel injection device according to claim 1, wherein the passage communicates with the first oil passage through a third oil passage.   A fuel injection device comprising a supply pump, a common rail that stores fuel pumped from the supply pump, and an injector that is connected to the common rail and injects fuel, wherein the common rail is provided with a pressure control valve. The supply pump is provided with a control rack for fuel metering, and the fuel pressure in the common rail is controlled by controlling the amount of fuel leaked from the pressure regulating control valve, and the control rack is controlled by the leaked fuel. A fuel injection device configured to control and control a discharge amount of fuel from a pressurized chamber of a supply pump to a common rail.   In the hydraulic head of the supply pump, a plunger, an inlet valve mechanism, an outlet valve mechanism, and a high-pressure pipe joint are arranged in order from the side closer to the cam that slides the plunger to the side farther from the cam. The fuel injection device according to any one of claims 1 to 3, wherein the structure and the high-pressure pipe joint are arranged on the same axis as the central axis of the plunger.   5. The fuel injection device according to claim 1, wherein in the supply pump, a plunger dropping prevention tool is provided outside the plunger sliding portion. 6.

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