JP4029424B2 - Fuel delivery pipe - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fuel for supplying fuel fed from a fuel pressurizing pump of an electronic fuel injection type automobile engine via a fuel injector (injection nozzle) for directly injecting the fuel into each intake passage or cylinder of the engine. The present invention relates to the improvement of the delivery pipe, and particularly relates to the cross-sectional structure of the communication pipe having the fuel passage and the external structure of the communication pipe.
[0002]
[Prior art]
Fuel delivery pipes are widely used in electronic fuel injection systems for gasoline engines. After fuel is sent from a communication pipe having a fuel passage to a fuel injector through a plurality of cylindrical sockets, the fuel delivery pipe is moved to the fuel tank side. There are a type having a return path for returning and a type having no return path (returnless). Recently, the type that does not have a return passage has been increasing due to measures to reduce transpiration gas with high-temperature return fuel and cost reduction. Along with this, the reflected wave caused by the reciprocating motion of the spool that opens and closes the valve to inject from the injector The fuel injection pulsation due to (shock wave) and pulsation pressure has caused a problem that the fuel delivery pipe and related parts vibrate and generate an unusual noise. In addition, abnormal noise was also generated due to the impact accompanying the seating of the injector spool.
In a so-called direct injection type engine in which fuel is directly injected into a combustion chamber, a high-pressure supply pump is provided. Therefore, a pulsation damper is provided to absorb the large pulsation, and a normal fuel injection type (MPI) Although it is also used in some cases in the case of engines, it is not easy to adopt due to space constraints and high costs.
[0003]
FIG. 8 shows a conventional example in which a part of the box-shaped cross section of the delivery pipes 1 and 2 is made an absorbing surface to absorb vibration. In FIG. 8A , an upper surface 95 facing the socket 3 connected to the fuel injection valve is made of a thin plate to provide an absorber surface, and in FIG. 8B , a side surface 96 is made of a thin plate to provide an absorber surface.
However, in this type of fuel delivery pipe, the socket protrudes from the lower side of the communication pipe, so that the total height of the communication pipe height H plus the protrusion height R of the socket becomes considerably large, and the interior of the engine room is narrow. There was a design problem that it could not be stored in the space. In addition, if the protruding height of the socket is increased, if the socket is tilted slightly during welding or brazing, an error at the free end of the socket becomes large, and a rework is required.
[0004]
Japanese Patent Laid-Open No. 10-331743 “Fuel distribution pipe structure for internal combustion engine” suppresses the generation of large radiated sound due to pulsation by increasing the rigidity of the fuel delivery pipe.
Japanese Patent Application Laid-Open No. 60-240867, “Fuel Supply Pipe for Fuel Injection Device for Internal Combustion Engine” is an elastic so as to attenuate fuel pulsation at least one of the walls of the fuel supply pipe in order to improve the fuel delivery pipe. It is configured.
Similarly, Japanese Patent Application Laid-Open No. 8-326622 “Fuel Pressure Pulsation Damping Device” and Japanese Patent Application Laid-Open No. 11-37380 “Delivery Pipe” also show devices for improving pulsation by improving the fuel delivery pipe.
[0005]
[Problems to be solved by the invention]
An object of the present invention is to provide a novel structure of a fuel delivery pipe that can reduce the shock wave and pulsation pressure generated when the fuel injector is opened and closed and can solve the above-mentioned design and manufacturing problems. There is to do.
[0006]
[Means for Solving the Problems]
According to the first aspect of the present invention, there is provided a communication pipe having a linearly extending fuel passage, a fuel introduction pipe fixed to an end portion or a side portion of the communication pipe, and the communication pipe. A fuel delivery pipe having a plurality of sockets projecting to intersect with the fuel passage and having an open end portion receiving the tip of the fuel injection nozzle. The outer wall surface of the communication pipe is flat or circular. A fuel that includes an arcuate and flexible absorber surface, and the upper end of the recess that receives the tip of the injection nozzle inside the socket penetrates into the inside of the communicating pipe further upward than the upper surface of the socket mounting portion inside the communicating pipe Achieved by delivery pipe.
[0007]
[Action]
By adopting such a structure, it is possible to reduce the pulsation pressure and shock wave of the fuel flowing into the socket by bending the absorber surface, while keeping the total height of the fuel delivery pipe low and improving the storage capacity in the engine room. It becomes possible.
In addition, the length of the socket protruding from the communication pipe is small, so even if the socket is tilted slightly during welding and brazing, the error at the free end of the socket does not increase and the need for correction or reworking decreases. Manufacturing advantages are obtained.
[0008]
As a preferred mode, if the mounting surface of the socket on the outer wall surface of the communication pipe is a non-flat surface such as a stepped surface or a bent surface, and the rigidity is higher than the other surfaces, the vibration transmission of noise generated around the socket It is possible to suppress the generation of abnormal noise by reducing the characteristics.
[0009]
The rationale for absorbing pulsation by the absorber surface is that the shock wave generated when the fuel injector is opened and closed flows into the socket's fuel inlet or flows out due to momentary reverse flow. It is understood that shock and pulsation are absorbed by this, and that a thin member having a relatively small spring constant is bent and deformed to change the volume and absorb fuel pressure fluctuations.
[0010]
In the present invention, the thickness of the absorber surface is preferably the same as or less than the thickness of the other surfaces. Further, it is desirable that the radius of curvature of the arc surface constituting the absorber surface is larger than twice the thickness of the absorber surface.
[0011]
In the present invention, the outer wall of the communication pipe, the thickness of the absorber surface, the aspect ratio, the gap between the socket and the surface facing the fuel inlet, etc., have the smallest values of vibration and pulsation especially when the engine is idling. It can be determined by experiment and analysis.
Since the present invention basically relates to the cross-sectional structure of the communication pipe and the external structure of the communication pipe, it is possible to maintain compatibility with the conventional fuel delivery pipe by maintaining the mounting dimensions of the bracket. it can. Other features and advantages of the present invention will become apparent from the following description with reference to the embodiments of the accompanying drawings.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
1A to 1C show a fuel delivery pipe 10 according to a first embodiment of the present invention, FIG. 1A is a perspective view of the whole, and FIG. 1B is a longitudinal sectional view with a part broken along a longitudinal direction of a communication pipe. 1C is a longitudinal sectional view of the socket portion.
For example, in the case of a four-cylinder engine, four sockets 3 are attached to the bottom surface of the communication pipe 11 extending along the crankshaft direction at a predetermined interval and angle. Further, two thick and rigid brackets 4 for attaching the fuel delivery pipe 10 to the engine body are bridged across the communication pipe 11 in the lateral direction. The fuel flows in the direction of the arrow and is directly injected from the socket 3 into each intake passage or cylinder via the fuel injector 6.
[0013]
The fuel introduction pipe 5 is fixed to the end of the communication pipe 11 having the fuel passage 12 inside by brazing or welding via a connector (not shown). Although a return pipe for returning to the fuel tank can be provided at the end of the communication pipe 11, the return-less fuel delivery pipe is not provided with a return pipe.
[0014]
As shown in FIG. 1C, in this example, the communication pipe 11 has a flat rectangular cross section formed by crushing a pipe made of carbon steel or stainless steel having a circular cross section. The vertical and horizontal dimensions of the communication pipe 11 can be set to, for example, a flat plate having a thickness of 1.2 mm, a height of 6.4 mm, and a width of about 32 mm.
[0015]
According to the feature of the present invention, the upper surface 11a facing the socket mounting surface 11b at the outer wall portion of the communication tube 11 having a flat rectangular cross section provides a flexible absorber surface, and this absorber surface faces the fuel inlet 13 of the socket 3. Therefore, it works to absorb vibration and shock during fuel injection. The clearance S between the upper surface 12a of the internal passage 12 of the communication pipe 11 and the fuel inlet 13 can be set to about 0.5 to 3 mm, for example.
Further, the upper end 3a of the recess 3b that receives the tip of the injection nozzle inside the socket 3 penetrates into the inside of the communicating pipe up to the upper surface 12b of the socket mounting portion inside the communicating pipe 11 (by dimension P).
Based on this structure, the pulsation pressure of the fuel flowing into the socket portion and the shock wave are reduced by bending the absorber surface while keeping the overall height of the fuel delivery pipe low.
[0016]
2A and 2B represent fuel delivery pipes 20 and 25, respectively, according to other embodiments. In FIG. 2A, the upper surface 21 a of the communication pipe 21 provides an absorber surface, and the upper end 3 a of the recess 3 b that receives the tip of the injection nozzle in the socket 3 extends to a position higher than the upper surface 12 b of the socket mounting portion in the communication pipe 21 ( Only dimension P) has penetrated into the communication pipe. In FIG. 2A, the mounting surface 21b of the socket of the outer wall surface of the communication pipe 21 is formed in the shape of a stepped surface, and the rigidity is higher than that of the absorber surface 21a. The generation of abnormal noise is suppressed by reducing the vibration transmission characteristics of the abnormal noise.
In FIG. 2B, the upper surface 26 a of the communication pipe 26 provides an absorber surface, and the upper end 3 a of the recess 3 b that receives the tip of the injection nozzle in the socket 3 extends to a position above the upper surface 12 b of the socket mounting portion in the communication pipe 26 ( Only dimension P) has penetrated into the communication pipe. Further, in FIG. 2B, the mounting surface 26b of the socket of the outer wall surface of the communication pipe 26 is formed in the shape of an arc-shaped bent surface, and the rigidity is higher than that of the absorber surface 26a. The generation of abnormal noise is suppressed by reducing the vibration transmission characteristics of abnormal noise emitted from the surroundings.
[0017]
FIGS. 3A-C show fuel delivery pipes 30, 33, 36 according to still other embodiments, in which the upper surfaces 31a, 34a, 37a of the communication pipes provide a flexible absorber surface. In addition, the upper ends 32a, 35a, 38a of the recesses 32b, 35b, 38b for receiving the tip of the injection nozzle in the sockets 32, 35, 38 are located above the upper surface 12b of the socket mounting portion in the communication pipe (only dimension P). It has entered the inside of the communication pipe.
The sockets 32, 35, and 38 are cut at the upper ends horizontally and have different cross-sectional shapes, but these can be freely deformed according to the mounting position and dimensions on the engine side. A projection 32c is provided at the lower end of the socket 32 in FIG. 3A, and this is a known structure as a detent for the injection nozzle.
[0018]
The examples of FIGS. 4 to 7 are modified examples incorporating device for manufacturing . In any of the examples, based on the characteristics of the present invention, the upper surface of each communication pipe is substantially flat or substantially arc-shaped and flexible. The upper end of the recess that provides the absorber surface and receives the tip of the injection nozzle inside the socket portion penetrates or extends beyond the upper surface 12b of the socket mounting portion inside the communication pipe (by dimension P).
[0019]
4 shows an example in which the socket peripheral portion 67 on the lower surface of the outer wall of the communication pipe 66 is deformed into an uneven shape to increase the rigidity . FIG. FIG. 6 shows an example in which 74 is deformed to increase the rigidity, and FIG. 6 shows that the socket peripheral portion 77 on the lower surface of the outer wall of the communication pipe 76 is deformed to increase the rigidity, and a reinforced portion (burring) 78 is provided on the upper side. FIG. 7 shows an example in which the brazing position and inclination accuracy are improved . FIG. 7 shows that a wrapping reinforcement portion (burring) 88 is formed around the socket on the lower surface of the outer wall of the communication pipe 85, This is an example in which a non-rotating stop 86 is provided and a ring-shaped collar 87 is arranged to improve the accuracy of brazing position and inclination.
[0020]
【The invention's effect】
As described above in detail, according to the present invention, the pulsation pressure of the fuel flowing into the socket and the shock wave are deflected on the absorber surface while keeping the height of the fuel delivery pipe low and improving the storage capacity in the engine room. In addition, the length of the socket protruding from the communication pipe is reduced, so even if the socket is tilted slightly during welding or brazing, the error at the free end of the socket does not increase and the socket is remade. The technical effects are quite significant, such as reducing the need for and providing manufacturing advantages.
[Brief description of the drawings]
FIG. 1 is a perspective view showing the entire fuel delivery pipe according to the present invention and a longitudinal sectional view of a socket portion.
FIG. 2 is a cross-sectional view of a socket portion according to another embodiment.
FIG. 3 is a cross-sectional view of a socket portion according to another embodiment.
FIG. 4 is a cross-sectional view of a socket portion according to another embodiment.
FIG. 5 is a cross-sectional view of a socket portion according to another embodiment.
FIG. 6 is a cross-sectional view of a socket portion according to another embodiment.
FIG. 7 is a cross-sectional view of a socket portion according to another embodiment.
FIG. 8 is a cross-sectional view of an absorber surface in a conventional delivery pipe.
[Explanation of symbols]
3, 32 Socket 3a, 32a Upper end 3b, 32b Recess 5 Fuel introduction pipe 10, 20, 30 Fuel delivery pipe 11, 21, 26 Communication pipe 11a, 21a, 26a Absorbing surface 11b, 21b, 26b Socket mounting surface 12 Fuel Passage 12b socket mounting part upper surface 13 Fuel inlet P Intrusion stretch dimension

Claims (2)

A communication pipe having a fuel passage extending in a straight line, a fuel introduction pipe fixed to an end portion or a side portion of the communication pipe, a portion projecting across the communication pipe and a part thereof communicating with the fuel passage In the fuel delivery pipe comprising a plurality of sockets whose open ends receive the fuel injection nozzle tips,
The outer wall surface of the communication pipe includes a flat or arcuate flexible absorber surface,
The upper end of the recess that receives the tip of the injection nozzle inside the socket penetrates into the inside of the communicating pipe further up than the upper surface of the socket mounting part inside the communicating pipe,
As a result, the fuel delivery pipe is characterized in that the pulsation pressure and shock wave of the fuel flowing into the socket are reduced by the deflection of the absorber surface while keeping the overall height of the fuel delivery pipe low. The fuel delivery pipe according to claim 1, wherein the mounting surface of the socket is a non-flat surface such as a stepped surface or a bent surface among the outer wall surfaces of the communication pipe and has higher rigidity than the other surfaces.

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