JP2009264166A - Delivery pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a delivery pipe can reduce cost, and reduce vibration and noise due to pulsation. <P>SOLUTION: The delivery pipe 1 includes a deliver pipe body 10 on which a plurality of injectors are mounted, and an internal fuel supply pipe 20 arranged inside the delivery pipe body 10 and extending from one end to other end side in an axial direction of the delivery pipe body 10. An opening 21 and a through-hole 22 as fuel supply ports are provided on the internal fuel supply pipe 20. The opening 21 and the through-hole 22 are arranged symmetrically with respect to a center C of the axial direction of the delivery pipe body 10. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a delivery pipe that is used in a fuel injection device of a multi-cylinder internal combustion engine and distributes fuel from a fuel pump to a plurality of fuel injection valves.

  As a fuel injection device of a multi-cylinder internal combustion engine mounted on a vehicle such as an automobile, there is one in which a plurality of fuel injection valves (injectors) are provided and fuel is injected from each injector into a corresponding intake passage or cylinder. In such a fuel injection device, a delivery pipe is used to distribute and supply the fuel from the fuel pump to the injectors. The fuel in the delivery pipe is injected and supplied to each intake passage or each cylinder at a predetermined pressure by controlling the opening and closing of the solenoid valve in each injector by the control unit.

By the way, in the fuel injection device as described above, since fuel injection is intermittently performed by opening and closing an electromagnetic valve inside the injector, there is a concern that pulsation (pressure fluctuation) may occur in the fuel pressure in the delivery pipe. . When such pulsation is propagated to the outside of the delivery pipe through a fuel supply pipe that supplies fuel to the delivery pipe, there is a possibility that vehicle vibration or noise may occur. Conventionally, as a countermeasure for reducing vibration and noise due to such pulsation, for example, a technique as disclosed in Patent Document 1 has been proposed.
JP 2000-329030 A

  However, as shown in Patent Document 1, when the fuel supply pipe is connected in the vicinity of the center in the axial direction (longitudinal direction) of the delivery pipe, there are the following problems. That is, there is a need to secure a mounting space for the fuel supply pipe, and in some cases, there is a concern that the mounting property may be deteriorated. In addition, when the delivery pipe is manufactured from a resin or the like, there is a concern that the manufacturing cost increases because the direction and number of times of die cutting increase.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a delivery pipe that can reduce vibration and noise due to pulsation as well as cost reduction.

  In the present invention, means for solving the above-described problems are configured as follows. That is, the present invention is a delivery pipe comprising a delivery pipe body, and a fuel supply pipe provided inside the delivery pipe body and extending from one end of the delivery pipe body toward the other end side in the axial direction, The fuel supply pipe is provided with at least two fuel supply ports, and these fuel supply ports are provided at substantially symmetrical positions with respect to the axial center of the delivery pipe body. Yes.

  According to the above configuration, since the fuel supply port of the fuel supply pipe is provided substantially symmetrically with respect to the center of the delivery pipe body in the axial direction, the length of the delivery pipe body in the axial direction is set to be almost a half wavelength. Propagation of low-frequency pulsation (referred to as primary pulsation) to the outside of the delivery pipe via the fuel supply pipe can be suppressed. For example, when the fuel supply pipe is configured to have two fuel supply ports, in the axial direction of the delivery pipe body, at the position where one fuel supply port is provided and the position where the other fuel supply port is provided, The primary pulsations have substantially opposite phases. For this reason, the primary pulsation propagated from one fuel supply port into the fuel supply pipe and the primary pulsation propagated from the other fuel supply port into the fuel supply pipe cancel each other. Thereby, the primary pulsation propagated to the outside through the fuel supply pipe or the like can be effectively attenuated, and the vibration and noise of the vehicle due to such primary pulsation can be reduced.

  Further, since the fuel supply pipe is disposed inside the delivery pipe body, the mountability can be improved as compared with the conventional example described above. Furthermore, when the delivery pipe main body is manufactured from resin or the like, the direction and number of die cutting can be reduced compared to the above-described conventional example, and the manufacturing cost can be reduced.

  In the present invention, the fuel supply pipe is provided with two fuel supply ports, and one of the fuel supply ports is provided in the vicinity of one-third of the axial length from one end of the delivery pipe body, and the other It is preferable that the fuel supply port is provided in the vicinity of one-fourth of the axial length from one end of the delivery pipe body.

  According to this configuration, in the axial direction of the delivery pipe body, the positions of the two fuel supply ports are both high-frequency pulsation (secondary pulsation) in which the axial length of the delivery pipe body is approximately one wavelength. ) In the vicinity of the part that becomes the node. As a result, the secondary pulsation can be prevented from propagating to the outside of the delivery pipe via the fuel supply pipe, and the vibration and noise of the vehicle due to such secondary pulsation can be reduced.

  In the present invention, it is preferable that each of the fuel supply ports is provided at a position opposite to a position facing a portion where the fuel injection valve is attached.

  Here, when a pressure wave generated with fuel injection from the fuel injection valve enters the fuel supply pipe through the fuel supply port, the pressure wave may be propagated to the outside of the delivery pipe. According to this configuration, such a pressure wave is difficult to enter directly into the fuel supply pipe, and almost all of the pressure wave reaching the fuel supply port of the fuel supply pipe is reflected on the wall surface of the delivery pipe body. It becomes. As a result, the pressure wave can be attenuated before reaching the fuel supply port, so that the pressure wave propagating to the outside of the delivery pipe via the fuel supply pipe can be suppressed as compared with the configuration in which the pressure wave directly enters. The vibration and noise of the vehicle due to such pressure waves can be reduced.

  In the present invention, it is preferable that a protruding portion in contact with the inner wall surface of the delivery pipe main body is integrally formed at the tip of the fuel supply pipe.

  According to this configuration, even if a fixing member is not provided, the protruding portion formed integrally with the fuel supply pipe is in contact with the inner wall surface of the delivery pipe body, so that the fuel supply pipe is positioned at a predetermined position in the delivery pipe body. Supported. As a result, the cost can be reduced as much as the fixing member is eliminated, and the assemblability can be improved.

  According to the present invention, the fuel supply pipe is provided inside the delivery pipe body, and the fuel supply port is provided substantially symmetrically with respect to the axial center of the delivery pipe body. Therefore, it is possible to reduce vibration and noise due to pulsation as well as cost reduction.

  The best mode for carrying out the present invention will be described with reference to the accompanying drawings.

  A delivery pipe to which the present invention is applied constitutes a part of a fuel injection device in a multi-cylinder engine, and distributes and supplies fuel from a fuel pump to a plurality of fuel injection valves (injectors). In the following embodiment, an example in which the present invention is applied to a delivery pipe provided in a fuel injection device for an in-line four-cylinder engine will be described. However, the present invention can be applied to an engine of any type and number of cylinders.

  FIG. 1 is a cross-sectional view showing an embodiment of a delivery pipe to which the present invention is applied.

  As shown in FIG. 1, the delivery pipe 1 includes a delivery pipe main body 10, and the other end from the one end (the left end in FIG. 1) in the axial direction (longitudinal direction) of the delivery pipe main body 10. And an internal fuel supply pipe 20 extending toward the end side (the right end side in FIG. 1). The internal fuel supply pipe 20 is connected to an external fuel supply pipe (external pipe) 2 extending from the fuel tank (fuel pump) side via a connector 3 at one end of the delivery pipe body 10. The delivery pipe 1 is supplied with fuel pumped by a fuel pump through the external fuel supply pipe 2. The delivery pipe 1 is a so-called returnless type that does not include a return passage for returning fuel to the fuel tank side.

  The delivery pipe main body 10 is a molded product made of resin, with one end (left end in FIG. 1) in the axial direction (longitudinal direction) opened and the other end (right end in FIG. 1) closed. It is formed in a substantially cylindrical shape. A cap 11 is integrally attached to the left end portion of the delivery pipe body 10 by welding or the like. An internal space extending along the axial direction of the delivery pipe body 10 is a fuel storage space. As the resin, for example, a synthetic resin such as polyamide, fluorine resin, polyphenyl sulfide, or polypropylene can be used. Note that the delivery pipe main body 10 and the cap 11 may be made of a metal such as aluminum or iron. In this case, the cap 11 is joined to the delivery pipe main body 10 by welding or brazing. Further, the cross-sectional shape of the delivery pipe body 10 may be a shape other than a circle (for example, a rectangle). Alternatively, the delivery pipe main body 10 may be configured to be open at both ends, and the cap 11 may be attached to both ends.

  An attachment portion 12 for attaching an injector is formed on the bottom portion (lower portion) of the delivery pipe main body 10. The attachment portion 12 is formed in a substantially cylindrical shape and protrudes from the bottom portion of the delivery pipe body 10 to the outside. The same number of mounting portions 12 as the number of cylinders (four in this embodiment) are provided, and are arranged at predetermined intervals in the axial direction. An injector is inserted into the attachment portion 12 via a seal member such as an O-ring. In addition, it is good also as a structure which attaches an injector to the delivery pipe main body 10 using a socket etc.

  The cap 11 is formed with a circular mounting hole 11 a for mounting the connector 3. The central portion 3a of the connector 3 is press-fitted into the mounting hole 11a. The outer periphery of the central portion 3a of the connector 3 is in close contact with the cap 11 by welding or the like.

  The connector 3 is a connecting member that connects the external fuel supply pipe 2 and an internal fuel supply pipe 20 described later. The external fuel supply pipe 2 is fitted into the outer end portion (left end portion in FIG. 1) 3b of the connector 3, and the internal fuel supply pipe 20 is fitted into the inner end portion (right end portion in FIG. 1) 3c. Yes. A plurality of projections 3d for pipe connection are formed on the outer circumferences of both end portions 3b and 3c of the connector 3, respectively. These protrusions 3d are in pressure contact with the inner peripheral surface of the external fuel supply pipe 2 and the inner peripheral surface of the internal fuel supply pipe 20, so that the connection between the external fuel supply pipe 2 and the outer end 3b of the connector 3 and the internal The connection between the fuel supply pipe 20 and the inner end 3c of the connector becomes strong.

  The internal fuel supply pipe 20 is a member constituting a fuel passage inside the delivery pipe body 10. The internal fuel supply pipe 20 is a molded product made of resin and is formed in a substantially cylindrical shape. The internal fuel supply pipe 20 extends along the axial direction of the delivery pipe body 10. As the resin, for example, nylon or a synthetic resin made of the same material as the delivery pipe main body 10 can be used. In addition, you may manufacture the internal fuel supply pipe | tube 20 with metals, such as aluminum, for example. The cross-sectional shape of the internal fuel supply pipe 20 may be a shape other than a circle (for example, a rectangle or an ellipse). Details of the internal fuel supply pipe 20 will be described later.

  A resin-made fixing ring 13 is fitted into the distal end portion (the other end portion) of the internal fuel supply pipe 20. As shown in FIG. 2, the fixing ring 13 is a member having an almost elliptical shape (or an oval shape), and has a circular insertion hole 13 a into which the tip of the internal fuel supply pipe 20 is inserted at the center. Is formed. The fixing ring 13 is press-fitted into the delivery pipe body 10 and fixed at a predetermined position. The internal fuel supply pipe 20 is supported by the fixing ring 13 and the connector 3 and is fixed at a predetermined position in the delivery pipe body 10.

  In the fuel injection device provided with such a delivery pipe 1, the fuel pumped by the fuel pump passes through the external fuel supply pipe 2, the connector 3, and the internal fuel supply pipe 20, and then the space inside the delivery pipe body 10. Supplied and stored. As the solenoid valve inside the injector opens and closes, fuel is injected from each injector into the corresponding intake passage or cylinder.

  Next, the internal fuel supply pipe 20 will be described in detail.

  In the delivery pipe 1, the internal fuel supply pipe 20 is provided with at least two fuel supply ports for supplying fuel to the space inside the delivery pipe body 10. In this embodiment, two fuel supply ports are provided in the internal fuel supply pipe 20. More specifically, an opening 21 at the tip of the internal fuel supply pipe 20 and a circular through hole 22 provided in the middle in the axial direction serve as a fuel supply port.

  The opening 21 of the internal fuel supply pipe 20 is provided in the vicinity of a position corresponding to three quarters of the axial length L from one end of the delivery pipe body 10. In this case, the opening end of the opening 21 is provided in the vicinity of the position of three quarters of the axial length L from one end of the delivery pipe body 10. That is, the internal fuel supply pipe 20 extends from one end of the delivery pipe main body 10 to the vicinity of the position of three quarters of the axial length L.

  The through hole 22 of the internal fuel supply pipe 20 is provided in the vicinity of a position that is a quarter of the axial length L from one end of the delivery pipe body 10. In this case, the center of the through hole 22 is provided in the vicinity of a position that is a quarter of the axial length L from one end of the delivery pipe body 10. That is, the through hole 22 is formed in the vicinity of one-third of the axial length (≈ (3/4) L) of the internal fuel supply pipe 20 from one end of the delivery pipe body 10. The shape of the through hole 22 may be a shape other than a circle (for example, a rectangle or an ellipse).

  According to this embodiment, the following effects can be obtained.

  In the delivery pipe 1, the opening 21 and the through hole 22 of the internal fuel supply pipe 20 are provided at substantially the same distance from the center C in the axial direction of the delivery pipe body 10. In other words, the opening 21 and the through hole 22 of the internal fuel supply pipe 20 are provided at substantially symmetrical positions with respect to the center C in the axial direction of the delivery pipe body 10. As a result, a low-frequency pulsation (referred to as a primary pulsation) in which the axial length L of the delivery pipe body 10 is approximately half a wavelength propagates to the outside of the delivery pipe 1 via the internal fuel supply pipe 20. It can be suppressed. Specifically, in the axial direction of the delivery pipe body 10, the primary pulsations are substantially opposite in phase at the position where the opening 21 is provided and the position where the through hole 22 is provided. For this reason, the primary pulsation propagated from the opening 21 into the internal fuel supply pipe 20 and the primary pulsation propagated from the through hole 22 into the internal fuel supply pipe 20 cancel each other. Thereby, the primary pulsation propagated to the outside through the internal fuel supply pipe 20 and the external fuel supply pipe 2 can be effectively attenuated, and the vibration and noise of the vehicle due to such primary pulsation can be reduced. Can be reduced. In addition, by performing simulation calculation or experiment in advance and setting the ratio of the opening area of the through hole 22 to the opening area of the opening 21 of the internal fuel supply pipe 20, the position of the through hole 22, and the like, the internal fuel described above It is possible to enhance the canceling action of the pulsation in the supply pipe 20.

  In addition, since the internal fuel supply pipe 20 is disposed inside the delivery pipe main body 10, the mountability can be improved as compared with the conventional example described above. Furthermore, since the internal fuel supply pipe 20 and the external fuel supply pipe 2 are connected to each other at one end of the delivery pipe body 10, the direction and frequency of die cutting can be reduced as compared with the conventional example described above, and the manufacturing cost can be reduced. Can be reduced.

  Although the embodiment of the present invention has been described above, the embodiment shown here is an example and can be variously modified.

  The positions of the opening 21 and the through hole 22 as fuel supply ports may be other than the positions described above as long as they are positions that are substantially symmetrical with respect to the center C in the axial direction of the delivery pipe body 10. Here, if the opening 21 and the through hole 22 of the internal fuel supply pipe 20 are provided at the position of the above-described embodiment, the following effects can be obtained. That is, in the axial direction of the delivery pipe body 10, the position of the opening 21 and the position of the through-hole 22 are both high-frequency pulsations (second-order pulsations such that the axial length L of the delivery pipe body 10 is approximately one wavelength. It is in the vicinity of the part that becomes the node of pulsation). Thereby, it is possible to suppress the secondary pulsation from being propagated outside the delivery pipe 1 via the internal fuel supply pipe 20, and to reduce the vibration and noise of the vehicle due to such secondary pulsation. Can do.

  The number of fuel supply ports of the internal fuel supply pipe 20 may be three or more as long as the fuel supply ports are provided substantially symmetrically with respect to the center C in the axial direction of the delivery pipe body 10. . FIG. 3 shows an example in which three fuel supply ports are provided in the internal fuel supply pipe 20. As shown in FIG. 3, the internal fuel supply pipe 20 is formed with a circular through hole 23 in addition to two fuel supply ports (opening 21 and through hole 22) provided at the same position as in the above embodiment. . Specifically, the through hole 23 is provided near the center C in the axial direction of the delivery pipe body 10. In this case, the center of the through hole 23 is provided near the center C in the axial direction of the delivery pipe body 10.

  In the above embodiment, the tip opening 21 of the internal fuel supply pipe 20 is an example of a fuel supply port. However, a through hole serving as a fuel supply port is provided without opening the tip of the internal fuel supply pipe 20. May be provided separately. In this case, the tip of the internal fuel supply pipe 20 may reach the other end of the delivery pipe body 10 or may not reach the other end. In short, the fuel supply port on the most front end side (the other end side) of the internal fuel supply pipe 20 may be a front end opening of the internal fuel supply pipe 20 or a through hole other than the front end opening.

  For example, as shown in FIG. 4, the internal fuel supply pipe 20 may be configured to have a closed end, and a through hole 24 as a fuel supply port may be formed in the internal fuel supply pipe 20. In this case, the center of the through hole 24 is provided in the vicinity of the position of three quarters of the axial length L from one end of the delivery pipe body 10. And the through-hole 24 is provided substantially symmetrically with respect to the center C of the axial direction of the through-hole 22 and the delivery pipe main body 10 provided in the same position as the said embodiment.

  Here, as a more preferable configuration, there is a configuration in which each fuel supply port is provided at a position opposite to the position facing the mounting portion 12 of the injector of the internal fuel supply pipe 20. For example, as shown in FIG. 4, since the injector mounting portion 12 is provided facing the lower portion of the internal fuel supply pipe 20, the two through holes 22 and 24 serving as fuel supply ports are provided in the internal fuel supply pipe 20. A structure provided on the top of the slab may be used.

  And according to this structure, the following effects can also be obtained. That is, when a pressure wave generated by fuel injection from each injector connected to the delivery pipe body 10 enters the internal fuel supply pipe 20 through the through holes 22 and 24, it propagates to the outside of the delivery pipe 1. There is a possibility that. In this example, such a pressure wave is difficult to directly enter the internal fuel supply pipe 20, and almost all pressure waves reaching the through holes 22 and 24 of the internal fuel supply pipe 20 are generated in the delivery pipe body 10. It is reflected on the upper wall. As a result, the pressure wave can be attenuated until it reaches the through holes 22, 24, so that the pressure wave is propagated to the outside through the internal fuel supply pipe 20 and the external fuel supply pipe 2 compared to the configuration in which the pressure wave directly enters. The pressure wave can be suppressed, and the vibration and noise of the vehicle due to such a pressure wave can be reduced.

  In the above, the example in which the internal fuel supply pipe 20 is supported on the delivery pipe body 10 by using the fixing ring 13 has been described. However, if the internal fuel supply pipe 20 can be supported by the delivery pipe body 10 The fixing ring 13 is not always necessary. For example, a protruding portion that contacts the inner wall surface of the delivery pipe body 10 may be integrally formed at the tip of the internal fuel supply pipe 20 and the internal fuel supply pipe 20 may be supported using this protruding portion. In this case, the number of protruding portions may be one or plural, but it is preferable to provide protruding portions that are in contact with at least two locations on the inner wall surface of the delivery pipe body 10. For example, the tip of the internal fuel supply pipe 20 may have a shape in which the diameter is expanded (expanded) outward, and the internal fuel supply pipe 20 may be supported using the expanded diameter portion (expanded portion).

  Specifically, as shown in FIGS. 5 and 6, the upper and lower portions of the distal end portion of the internal fuel supply pipe 20 are expanded outward, and the opening 21 at the distal end is viewed from one of the axial directions. It is formed in a substantially elliptical shape (or a substantially oval shape). In this case, the starting positions of the enlarged diameter portions 25 and 26 of the internal fuel supply pipe 20 are provided in the vicinity of the position of three quarters of the axial length L from one end of the delivery pipe body 10.

  The upper and lower enlarged diameter portions 25 and 26 formed at the tip of the internal fuel supply pipe 20 are in contact with the inner wall surface of the delivery pipe body 10. Accordingly, the internal fuel supply pipe 20 is supported at a predetermined position in the delivery pipe body 10 by the upper and lower diameter enlarged portions 25 and 26 and the connector 3 which are integrally formed with the internal fuel supply pipe 20. According to this configuration, the internal fuel supply pipe 20 can be supported at a predetermined position in the delivery pipe body 10 without using the fixing ring 13, so that the cost can be reduced and the assemblability can be improved. Can be improved. A configuration may be adopted in which an enlarged diameter portion extending in the lateral direction is provided at the tip of the internal fuel supply pipe 20.

  In the above, an example in which the internal fuel supply pipe 20 and the external fuel supply pipe 2 are connected via the connector 3 has been described. That is, an example in which separate fuel supply pipes are used inside and outside the delivery pipe main body 10 has been described, but a configuration in which an integral fuel supply pipe is used inside and outside the delivery pipe main body 10 may be adopted. That is, the fuel supply pipe extending from the fuel tank (fuel pump) side may be inserted into the inside from one end of the delivery pipe main body 10 as it is, and at least two fuel supply ports may be provided in the insertion portion.

It is sectional drawing which shows one Embodiment of the delivery pipe to which this invention is applied. It is the figure which looked at the inside of the delivery pipe of FIG. 1 from one direction of the axial direction. It is sectional drawing which shows the modification (example which provided three fuel supply ports) of the delivery pipe. It is sectional drawing which shows the modification (example which provided the fuel supply port on the opposite side to an injector) of a delivery pipe. It is sectional drawing which shows the modification (example which expanded the diameter of the front-end | tip part of an internal fuel supply pipe) of a delivery pipe. It is the figure which looked at the inside of the delivery pipe of FIG. 5 from one direction of the axial direction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Delivery pipe 10 Delivery pipe main body 20 Internal fuel supply pipe 21 Opening 22 Through-hole

Claims (4)

A delivery pipe comprising a delivery pipe body and a fuel supply pipe provided inside the delivery pipe body and extending from one end in the axial direction of the delivery pipe body toward the other end,
The fuel supply pipe is provided with at least two fuel supply ports,
These fuel supply ports are provided at substantially symmetrical positions with respect to the axial center of the delivery pipe body. The delivery pipe according to claim 1,
The fuel supply pipe is provided with two fuel supply ports,
One fuel supply port is provided near one third of the axial length from one end of the delivery pipe body, and the other fuel supply port is one quarter of the axial length from one end of the delivery pipe body. A delivery pipe characterized by being provided near the position. The delivery pipe according to claim 1 or 2,
Each of the fuel supply ports is provided at a position opposite to a position facing a portion to which the fuel injection valve is attached. In the delivery pipe according to any one of claims 1 to 3,
A delivery pipe characterized in that a projecting portion in contact with an inner wall surface of the delivery pipe main body is integrally formed at a tip portion of the fuel supply pipe.

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