JP4240835B2 - Fuel injection device for internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fuel injection device for an internal combustion engine, and in particular, in a multi-cylinder internal combustion engine having a complicated fuel supply system configuration such as a V-type or horizontally opposed engine, a fuel supply system by pulsation of discharge pressure of a high-pressure fuel pump. It is related with the fuel-injection apparatus comprised so that the fluctuation | variation of the fuel pressure by the resonance which generate | occur | produces could be suppressed as low as possible.
[0002]
[Prior art]
In a direct injection type fuel injection device that directly injects fuel such as gasoline into a cylinder of an engine (internal combustion engine), a high-pressure fuel injection pump (also called a high-pressure fuel pump or simply a high-pressure pump) is downsized. A single cylinder with a single plunger for ease of installation in the engine and for use in place of a relatively high cost multi-cylinder high pressure pump to reduce costs High-pressure pumps are often used. Generally, a high-pressure fuel pipe that supplies fuel in a fuel tank to a fuel injection valve, and a high-pressure pump that is provided in the middle of the pipe and raises the pressure (fuel pressure) of the fuel to a high-pressure injection pressure required in the fuel injection valve A delivery pipe (also referred to as a common rail) that distributes fuel boosted by a high-pressure pump to a plurality of fuel injection valves provided for each cylinder, and injects high-pressure fuel supplied from the delivery pipe into each cylinder. A fuel injection device comprising the injection valve is well known.
[0003]
However, this type of high-pressure pump has a pulsating discharge pressure of the high-pressure pump because one plunger repeats a suction stroke and a discharge stroke. Fluctuates depending on Therefore, the amount of fuel injected from the fuel injection valve into the cylinder increases when the fuel pressure in the delivery pipe is high and decreases when the fuel pressure is low. Thus, when the injection amount of the fuel injected into the cylinder changes according to the fluctuation of the fuel pressure, there arises a problem that the output of the engine also fluctuates.
[0004]
In particular, in a multi-cylinder internal combustion engine such as a V-type 8-cylinder, high-pressure pumps are provided in two delivery pipes, one for each of the left and right banks, and fuel is supplied by the two high-pressure pumps. In the fuel injection device supplied to the delivery pipe, as described in Japanese Patent Application Laid-Open No. 11-44276, the discharge pulsation generated by the two high-pressure pumps by shifting the discharge timings of the two high-pressure pumps. The fuel pressure fluctuations can be reduced by configuring the fuel cells to cancel each other. However, in the configuration as shown in this prior art, when the resonance frequency inherent in the piping system matches the discharge pulsation frequency of the high-pressure pump and the frequency of its higher order components, resonance occurs and the delivery pipe There is a problem that the fluctuation of the internal fuel pressure increases, and the fuel injection amount fluctuates, thereby causing fluctuations in engine output.
[0005]
[Problems to be solved by the invention]
The present invention aims to address the above-mentioned problems in the prior art and solve these problems by novel means.
[0006]
[Means for Solving the Problems]
The present invention provides, as means for solving the above-described problems, a fuel injection device described in each claim.
[0007]
In the fuel injection device according to claim 1, the first and second delivery pipes, the first connecting pipe that connects portions close to one end thereof, and the second that connects portions close to the other end. A large volume is interposed in the fuel supply path connecting the first or second high-pressure pump and one fuel injection valve because they form one closed loop. Therefore, as a result of the large volume absorbing the discharge pulsation of the first and second high-pressure pumps, fluctuations in fuel pressure in the delivery pipe and at the inlet of the fuel injection valve are reduced. Moreover, the ejection timing of the first and second high-pressure pumps are shifted from each other by half a cycle, since the discharge pulsation of the first and second high-pressure pump is set to be opposite phases in this way, one of the delivery pipe A large fluctuation component is canceled out by the fuel pressure fluctuation in one and the fuel pressure fluctuation in the other delivery pipe interfering with each other via the two connecting pipes. As a result, the fuel pressure fluctuation is reduced in both the first and second delivery pipes, the fuel injection amount injected from the fuel injection valve is stabilized, and the problem of engine output fluctuation is solved.
[0008]
In the fuel injection device according to claim 2, whether the position close to one end of the first and second delivery pipes is connected by the connecting pipe, and the inner diameter of the delivery pipe is 1.33 times or less of the inner diameter of the connecting pipe. In terms of the cross-sectional area, the cross-sectional area of the delivery pipe is 1.78 times or less that of the connecting pipe so that a large difference in inner diameter does not occur at the joint between the delivery pipe and the connecting pipe or the high-pressure pipe. As a result, a part of the delivery pipe acts as a pipe continuous with the connecting pipe and the high-pressure pipe, and no pressure wave reflection occurs at the joint, so the high-pressure pipe connecting the first and second high-pressure pumps. The length of the pipe consisting of the connecting pipe and the like becomes the longest pipe length, and it becomes dominant with respect to the resonance frequency. By reducing this length as much as possible, the resonance frequency of the entire fuel injection device It is possible to make the resonance with the discharge pulsation of the high-pressure pump difficult to move. Also, in claim 2, the discharge timings of the first and second high-pressure pumps are shifted from each other by a half cycle, and the same effect as in claim 1 is achieved.
[0011]
In the fuel injection device according to claim 3 , in the normal operation state, the fuel pressure fluctuation is caused by the connecting pipe that connects the two delivery pipes by shifting the discharge timing of the first and second high-pressure pumps by 1/2 period. The relative discharge timings of the two high-pressure pumps are operated so that the discharge timings of the first and second high-pressure pumps are in phase with each other at and around the rotational speed at which resonance occurs. It is characterized in that it changes according to the state. This is based on the result of finding through experiments that the fuel pressure fluctuation is reduced when the phase is the same in the region where resonance occurs.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows the configuration of a fuel injection apparatus as a first embodiment of the present invention. This fuel injection device is for application to a V-type 8-cylinder engine as an example. Since the first embodiment is a basic embodiment of the present invention, the first embodiment includes many common parts with the second and following embodiments. Accordingly, in the following embodiments, the substantially same components as those in the first embodiment will be denoted by the same reference numerals and the description thereof will be omitted.
[0014]
In the figure, reference numerals 1 and 2 denote high-pressure pumps (high-pressure fuel injection pumps). These independent high-pressure pumps 1 and 2 belong to so-called plunger pumps, each having one plunger, a pump cylinder for reciprocating these plungers, and an engine body for reciprocating each plunger. Are provided with elliptical pump cams 21 and 22 that are rotationally driven by the motor. The two high-pressure pumps 1 and 2 are connected to the common low-pressure pipe 3 on the suction side, and receive low-pressure fuel from the low-pressure pipe 3 and pressurize it, thereby boosting the fuel to a pressure of about 15 MPa, for example. The high-pressure fuel is discharged to delivery pipes (or common rails) 6 and 7 separately provided in the cylinder heads of the left and right banks of the V-type engine via high-pressure pipes 4 and 5, respectively.
[0015]
The delivery pipes 6 and 7 are each provided with four fuel injection valves 8 corresponding to four cylinders belonging to the left and right banks of the V-type 8-cylinder engine, and fuel injection from an electronic control device (not shown). When the signal is received, the valve is opened independently, and the fuel in the delivery pipe 6 or 7 is injected into each cylinder and burned. In the middle of the high-pressure pipes 4 and 5, throttle portions 9 and 10 whose cross-sectional area is suddenly reduced are provided, and high-pressure fuel is supplied to the delivery pipes 6 and 7 while reducing the discharge pulsation of the high-pressure pumps 1 and 2. It is supposed to be.
[0016]
The structural features of the fuel injection device of the first embodiment shown in FIG. 1 are such that the portions close to the front ends of the first and second delivery pipes 6 and 7 are connected to the portions close to the rear ends. Two connecting pipes 11 and 12 are provided. Accordingly, the first and second delivery pipes 6 and 7 and the connecting pipes 11 and 12 before and after the first and second delivery pipes 6 and 7 have a closed loop shape or an annular shape. Such a configuration has two delivery pipes 6 and 7, front and rear connecting pipes 11 and 12, and a higher pressure, interposed in the fuel supply path from the high-pressure pump 1 or 2 to any one of the fuel injection valves 8. A large volume consisting of the sum of the volumes of the pipes 4, 5, etc. is provided.
[0017]
In the first embodiment, since the pump cams 21 and 22 are both elliptical cams, for example, in an engine having a maximum rotation speed of 7000 rpm in the normal rotation speed range, as described above, it is specific to the piping system. In order to prevent the fuel pressure pulsation in the delivery pipes 6 and 7 from increasing due to the resonance that occurs when the resonance frequency of the high pressure pump 1 and the discharge pulsation frequency of the high-pressure pumps 1 and 2 or the higher order components thereof are synchronized. The following are excluded because they are less harmful due to resonance, and only the discharge pulsation frequency of the high-pressure pumps 1 and 2 and the higher order components of the order 3 or less (that is, the second and third order higher order components) are considered. And the resonant frequency f due to the resonance of the pipe is L = the pipe length f = 890 [ms] / (2 * L) [m]
If so, the target frequency to be cleared is the same as the frequency of the third-order higher-order component and is 350 Hz.
[0018]
In the first embodiment of the present invention, as shown in FIG. 1, the portions close to the front ends of the two delivery pipes 6 and 7 are connected by the connecting pipe 11 and the portions close to the rear ends are connected. Since the two connection pipes 6 and 7 in the form of closed loops and the front and rear connection pipes 11 and 12 form a large volume because they are connected by the connection pipe 12, the frequency of the discharge pulsation of the high-pressure pumps 1 and 2 is increased. Alternatively, it is possible to prevent the resonance with the higher order component twice or three times. Thereby, regardless of the magnitude of the discharge pulsation frequency of the high-pressure pumps 1 and 2, an increase in fuel pressure fluctuation due to resonance can be suppressed. In this case, the numerical values related to the shape of the pipe line such as the inner diameter and length of the connecting pipes 11 and 12 and the inner diameter and length of the delivery pipes 6 and 7 indicate the magnitude of the fluctuation of the fuel pressure at the inlet of each fuel injection valve 8. It becomes an important factor to decide. Generally, when the volume of the delivery pipes 6 and 7 is increased, the fuel pressure fluctuation is reduced.
[0019]
Needless to say, in the fuel injection device of the first embodiment, when setting the relative phase difference between the pump cams 21 and 22 of the first and second high-pressure pumps 1 and 2, When the discharge pulsation is in the opposite phase, the two delivery pipes 6 and 7 are connected by the front and rear connection pipes 11 and 12, so that these discharge pulsations interfere with each other and cancel each other. The fuel pressure fluctuation in the delivery pipes 6 and 7 is reduced.
[0020]
FIG. 2A shows the configuration of a fuel injection apparatus as a second embodiment of the present invention. The external features of the second embodiment different from the first embodiment shown in FIG. 1 are that a part of each of the first and second delivery pipes 6 and 7 is connected by a single connecting pipe 23. That is. Assuming that the connecting pipe 23, each part of the delivery pipes 6 and 7 and the high-pressure pipes 4 and 5 connected to the front ends thereof are a series of pipes, the total length thereof is L1. By changing the position where both ends of the connecting pipe 23 are attached to the delivery pipes 6 and 7, the longest pipe length L1 is changed to an arbitrary length.
[0021]
Another feature of the fuel injection device of the second embodiment is that the inner diameters of the first and second delivery pipes 6 and 7 are limited to 1.33 times or less the inner diameter of the connection pipe 11. By setting the internal cross-sectional area of the delivery pipes 6 and 7 to 1.78 times or less of the internal cross-sectional area of the connecting pipe 23, that is, by making the diameter ratio 1.33 times or less, the delivery pipe 6 , 7 is not recognized as a space having a remarkably large volume, and is regarded as a pipe continuous with the connecting pipe 23 and the high-pressure pipes 4, 5, so that reflection of pressure waves of the discharge pulsation of the high-pressure pump occurs at the joint. The resonance frequency due to the longest tube length L1 becomes dominant and the resonance frequency corresponding to the length L1 can be handled as the resonance frequency of the entire fuel injection device.
[0022]
As a specific numerical example regarding the second embodiment, when the inner diameter of the connecting pipe 23 is 6 mm and the inner diameter of the delivery pipes 6 and 7 is 8 mm, the length of the longest pipe that causes vibration at the lowest frequency. Since the influence of the length L1 is great, the resonance frequency is set to be higher than the target frequency (350 Hz) by connecting the connecting pipe 23 to the position on the delivery pipes 6 and 7 where the longest pipe length L1 is the shortest. To do. As an example, the length of the high-pressure pipes 4 and 5 from the high-pressure pumps 1 and 2 to the delivery pipes 6 and 7 is about 0.4 m, and the length of the delivery pipes 6 and 7 is 0.4 m, respectively. In order to make the length L1 from the high-pressure pump 1 to the high-pressure pump 2 the shortest when the length of the pipe 23 is about 0.25 m, the connecting pipe 23 is connected to the front ends (upstream end portions) of the delivery pipes 6 and 7. Is connected to a position closest to, the longest tube length L1 is 1.05 m, the resonance frequency is 424 Hz, and a resonance frequency sufficiently higher than the target frequency of 350 Hz can be set.
[0023]
In the diagram shown as (b) in FIG. 2, when the cross-sectional area ratio between the cross-sectional area of the delivery pipes 6 and 7 and the cross-sectional area of the connecting pipe 23 is taken on the horizontal axis, the cross-sectional area ratio is changed. This shows the result of an experiment to examine how the resonance frequency changes. It can be said that this diagram shows the relationship between the delivery pipes 6 and 7 and the connecting pipe 23. In addition, the diagram shown as (c) in FIG. 2 shows how the resonance frequency changes when the tube length L1 is changed by taking the longest tube length L1 on the horizontal axis. The results of the investigation are shown. It can be said that this diagram shows the magnitude of the influence of the longest tube length L1 on the resonance frequency.
[0024]
FIG. 3A shows the configuration of a fuel injection apparatus as a third embodiment of the present invention. A structural feature of the third embodiment is that a volume portion 13 is provided between the high-pressure pipes 4 and 5. The volume portion 13 is a chamber having a space having a volume sufficiently larger than the volume of the unit length of the high-pressure pipes 4 and 5. The high-pressure pipes 4 and 5 are divided into 4′4 ″, 5 ′ and 5 ″, respectively, and one end thereof is connected to one front end portion of the high-pressure pumps 1 and 2 or the delivery pipes 6 and 7 and the other end Are intensively connected to the volume unit 13. As a result, the high-pressure pipes 4 and 5 communicate with each other via the volume unit 13, so that the discharge pulsation generated in the high-pressure pumps 1 and 2 is absorbed by the large volume of the volume unit 13, or each of the high-pressure pumps 1 and 2. If the ejection pulsations generated by the above are in reverse phase, they will interfere with each other in the volume portion 13 and cancel each other.
[0025]
In the third embodiment, since the high-pressure pipes 4 and 5 are connected via the volume part 13 having a sufficiently large volume, the elliptical pump cams 21 and 22 which are double cams as shown in FIG. When the phase is shifted by a half cycle using a high pressure pump having four crests, which is twice the number 2 of the protrusions of the pump cams 21 and 22, to the delivery pipe of the in-line four-cylinder engine This is essentially the same as supplying fuel. Therefore, the lowest resonance frequency generated in the pipe can be set to the resonance frequency corresponding to the length L2 of the delivery pipes 6 and 7, as shown in FIG. As an example, if the length of the delivery pipes 6 and 7 is 0.4 m, the resonance frequency is 1.1 kHz, so that the resonance frequency can be set to a value sufficiently higher than the target frequency of 350 Hz.
[0026]
FIG. 4 shows the configuration of a fuel injection apparatus as a fourth embodiment of the present invention. The feature of the fourth embodiment is that the discharge pulsation of the high-pressure pump is selected by appropriately selecting the number of pump cam peaks that drive the high-pressure pump when the resonance frequency of the fuel injection device cannot be changed for design reasons or the like. Is set so as to avoid synchronization with the resonance frequency by lowering the frequency to be lower than the resonance frequency. In such a system, the value obtained by dividing the discharge pulsation frequency [Hz] of the high pressure pump by the engine speed [rpm] is t, the resonance frequency [Hz] is f, and the discharge pulsation of the high pressure pump to be reduced. The order of the high-order component of the frequency is set to J (for example, J = 4 when the third-order or less of the frequency of the discharge pulsation is reduced), and the maximum engine speed [rpm ] Is R, the specifications may be set so as to satisfy the following conditional expression.
t ≦ 60 * f / (R * J)
[0027]
In the fourth embodiment shown in FIG. 4, only the portion related to the delivery pipe 7 that is one of the two delivery pipes 6, 7 is shown, but the portion related to the other delivery pipe 6. Are not shown because they are the same as those shown in the previous embodiments. Further, a connecting pipe or the like for connecting the two delivery pipes 6 and 7 may not be provided. Specifically, in the fourth embodiment, the pump cam 14 of the high-pressure pump 22 has three peaks having a substantially equilateral triangle shape. The pump cam 14 is rotationally driven by a crankshaft 19 of the engine via a camshaft 15, a driven pulley 16, a belt 17, and a driving pulley 18. In this case, since the camshaft 15 rotates once for two rotations of the crankshaft 19 and the pump cam 14 has three peaks, the ratio value t in the above conditional expression is 1.5. .
[0028]
FIG. 5A shows the configuration of a fuel injection apparatus as a fifth embodiment of the present invention. One of the structural features of the fifth embodiment is that a connecting pipe 23 for connecting the two delivery pipes 6 and 7 themselves to each other is provided in the same manner as the second embodiment shown in FIG. However, unlike the second embodiment, the optimum position can be freely selected without limiting the position where the end of the connecting pipe 23 is attached on the delivery pipes 6 and 7 to be close to the front end. Another feature of the fifth embodiment is that the relative phases of the two pump cams 21 and 22 can be changed in the range from the same phase to the opposite phase during operation. This is made possible by providing a valve timing adjusting mechanism known per se in the engine between at least one of the cam bodies of the pump cams 21 and 22 and the camshaft.
[0029]
Under normal operating conditions, the pump cams 21 and 22 are out of phase with each other. The fuel pressure fluctuations of the high pressure pumps 1 and 2 and the delivery pipes 6 and 7 in this case are shown in FIG. Since the delivery pipes 6 and 7 are connected to each other by the connecting pipe 23, the fluctuations in the fuel pressure inside them are substantially synchronized, and two pulsations of opposite phases generated by the high-pressure pumps 1 and 2 interfere with each other. As a result, the amplitude of the fuel pressure fluctuation is reduced in both the delivery pipes 6 and 7. That is, the pulsation is kept low.
[0030]
On the other hand, FIG. 5C shows fuel pressure fluctuations of the high-pressure pumps 1 and 2 and the delivery pipes 6 and 7 when the pump cams 21 and 22 are in the same phase in a normal operation state. Since the phases are the same, the discharge pulsations generated by the two high-pressure pumps 1 and 2 are superimposed, and the amplitude of the fuel pressure fluctuation in the delivery pipes 6 and 7 is increased. Therefore, as shown in FIG. 5 (d), in the region where the engine speed is 5000 rpm or less, the fluctuation in the fuel pressure in the delivery pipes 6 and 7 is smaller in the opposite phase than in the same phase. When resonance occurs in the vicinity of 6000 rpm, the fuel pressure fluctuation is larger in the opposite phase before and after the resonance point than in the same phase. The fifth embodiment pays attention to this property, and the relative phases of the pump cams 21 and 22 are set so that the pump cams 21 and 22 have opposite phases in the normal operation state but the same phase before and after the resonance point. Change according to the driving condition.
[0031]
Thereby, in the fifth embodiment, it is possible to always keep the fuel pressure fluctuation in the delivery pipes 6 and 7 low in all the operation regions. In this case, if the lengths of the two high-pressure pipes 4 and 5 connecting the high-pressure pumps 1 and 2 and the delivery pipes 6 and 7 are the same, the pump cams 21 and 22 are simply located near the resonance point as described above. The desired effect can be obtained by switching the relative phase of the two from the opposite phase to the same phase. However, if there is a difference in length between the two high-pressure pipes 4 and 5, it is necessary to make some corrections. is there. For example, in an environmental condition where there is a difference of 0.1 m between them and the propagation speed of the pressure wave is 890 m / s, the longer of the two high-pressure pipes 4 and 5 is connected. It is preferable to give a phase difference between the two pump cams 21 and 22 so that the discharge timing of the high-pressure pump 1 or 2 is earlier than that of the other by 0.1 / 890 = 0.000112 [s].
[0032]
FIG. 6A shows a fuel injection apparatus as a sixth embodiment of the present invention and a calculation formula for calculating the total impedance Z thereof. Also in the sixth embodiment, by connecting the appropriate positions of the two delivery pipes 6 and 7 with the connecting pipe 23, the pulsation of the fuel pressure in the delivery pipes 6 and 7 interferes with each other, and both fuel pressure fluctuations are reduced. Thus, the inner diameter and length of the connecting pipe are set to optimum values. However, rather than having a feature in the configuration of the fuel injection device, the sixth embodiment determines the inner diameter and length of the two delivery pipes 6 and 7 and the connecting pipe 23 provided to connect them. There is a feature in the technique to do. In FIG. 6A, the first high-pressure pump 1 and the throttle portion 9 are omitted.
[0033]
When the two delivery pipes 6 and 7 are connected by the connecting pipe 23, resonance occurs between them. By calculating this using the impedance method, the volume of the delivery pipes 6 and 7 and the length and inner diameter of the connection pipe 23 are set so that they provide a resonance frequency that is equal to or higher than the target frequency. FIG. 6B shows mathematical expressions for obtaining individual impedances used in this calculation and the meanings of symbols used in the respective mathematical expressions. 6 (c) shows a relationship between the inner diameter [mm] of the connecting pipe 23 and the resonance frequency [Hz] as a diagram, and FIG. 6 (d) shows a delivery pipe 6, The relationship between the volume [cc] of FIG. 7 and the resonance frequency [Hz] is shown as a diagram.
[0034]
As an example, in the fuel injection device in which the delivery pipes 6 and 7 each have a volume of 70 cc and the length of the single connecting pipe 23 is 0.25 m, the inner diameter of the connecting pipe 23 is set to 8 mm. Since the resonance frequency can be set to 370 Hz, the resonance frequency can be made higher than the target frequency of 350 Hz. Further, by setting the volume of each of the delivery pipes 6 and 7 to 50 cc or less, the resonance frequency can be made higher than the target frequency of 350 Hz.
[Brief description of the drawings]
FIG. 1 is a system configuration diagram of a first embodiment of the present invention.
FIGS. 2A and 2B show a second embodiment of the present invention, where FIG. 2A is a system configuration diagram, FIG. 2B is a diagram showing a relationship between a cross-sectional area ratio of a pipe and a resonance frequency, and FIG. It is a diagram which shows the relationship between the length of a pipe, and the resonant frequency.
FIGS. 3A and 3B show a third embodiment of the present invention, where FIG. 3A is a system configuration diagram, and FIG. 3B is a diagram showing the relationship between pipe length and resonance frequency.
FIG. 4 is a system configuration diagram of a fourth embodiment of the present invention.
FIGS. 5A and 5B show a fifth embodiment of the present invention, where FIG. 5A is a system configuration diagram, and FIG. 5B is a mutual connection with discharge pulsations of two high-pressure pumps when they are in opposite phases. Diagram showing fuel pressure fluctuations in two delivery pipes, (c) is a line showing discharge pulsations of two high-pressure pumps in the same phase and fuel pressure fluctuations in two interconnected delivery pipes FIG. 4D is a diagram showing the results of examining the degree of fuel pressure fluctuation that changes according to the change in engine speed in the case of the same phase as the opposite phase.
6A and 6B show a sixth embodiment of the present invention, in which FIG. 6A is a system configuration diagram and a calculation formula based on an impedance method, and FIG. 6B is a calculation formula for impedances of individual parts constituting a fuel injection device. (C) is a diagram which shows the relationship between the internal diameter of a connection pipe, and a resonance frequency, (d) is a diagram which shows the relationship between the volume of a delivery pipe, and a resonance frequency.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... 1st high pressure pump 2 ... 2nd high pressure pumps 4, 5 ... High pressure piping 6 ... 1st delivery pipe 7 ... 2nd delivery pipe 8 ... Fuel injection valve 11, 12 ... Connection pipe 13 ... Volume part 14 ... Pump cams 21, 22 ... Oval pump cam 23 ... Connecting pipe

Claims (3)

First and second high pressure pumps;
Each is formed as a tube having a plurality of fuel injection valves, and is provided for distributing the fuel discharged from the first and second high pressure pumps to the plurality of fuel injection valves and injecting the fuel into the internal combustion engine. First and second delivery pipes,
First and second high-pressure pipes connecting the first and second high-pressure pumps to one ends of the first and second delivery pipes, respectively;
A first connecting pipe for connecting portions close to the one end of the first and second delivery pipes;
A second connecting pipe for connecting portions close to the other ends of the first and second delivery pipes ;
The fuel injection device, wherein discharge timings of the first and second high-pressure pumps are shifted from each other by a half cycle . First and second high pressure pumps;
Each is formed as a tube having a plurality of fuel injection valves, and is provided for distributing the fuel discharged from the first and second high pressure pumps to the plurality of fuel injection valves and injecting the fuel into the internal combustion engine. First and second delivery pipes,
First and second high-pressure pipes connecting the first and second high-pressure pumps to one ends of the first and second delivery pipes, respectively;
A connecting pipe for connecting portions close to the one end of the first and second delivery pipes;
The inner diameter of the first and second delivery pipes is not more than 1.33 times the inner diameter of the connecting pipe, or the sectional area of the first and second delivery pipes is one of the sectional area of the connecting pipe. .78 times Ri der any of the following, and
The fuel injection device, wherein discharge timings of the first and second high-pressure pumps are shifted from each other by a half cycle . First and second high-pressure pumps capable of relatively changing the discharge timing;
Each is formed as a tube having a plurality of fuel injection valves, and is provided for distributing the fuel discharged from the first and second high pressure pumps to the plurality of fuel injection valves and injecting the fuel into the internal combustion engine. First and second delivery pipes,
First and second high-pressure pipes connecting the first and second high-pressure pumps to one ends of the first and second delivery pipes, respectively;
A connecting pipe that connects each part of the first and second delivery pipes, and
In a normal operating state, the discharge pulsation is mutually offset as an opposite phase by shifting the discharge timing of the first and second high-pressure pumps by 1/2 period. A fuel injection device characterized in that the discharge timings of the first and second high-pressure pumps are in phase.

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