JP2008088982A - Piping structure of fuel injection pipe for engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piping structure of fuel injection pipes for an engine having advantages of improving engine performance by reducing dispersion of the fuel injection quantity, and improving productivity and reliability of the piping structure. <P>SOLUTION: Cylinder heads 100a-100f are provided with fuel injection valves 101a-101f respectively. The respective fuel injection valves 101a-101f are connected to joints 105a-105f in a common rail extending in aline through the fuel injection pipes 103a-103f. In this case, the fuel injection pipes 103b, 103c, 103d, 103e are crossed and connected to equalize the length of all the fuel injection pipes 103a-103f. Dispersion of the fuel injection quantity can thereby be reduced to improve engine performance. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a piping structure of a fuel injection pipe applied to a diesel engine or the like. In particular, the present invention relates to a piping structure of an engine fuel injection pipe having advantages such as reduction in variation in fuel injection amount to improve engine performance, and improvement in productivity and reliability of the piping structure.

As a conventional example of a fuel injection device for an internal combustion engine, for example, Japanese Patent No. 2797745 (Patent Document 1) can be cited.
FIG. 7 is a plan view of the fuel injection device disclosed in Patent Document 1. FIG.
The diesel engine shown in FIG. 7 has six cylinders, and fuel injection valves 1a to 1f are provided in the respective cylinders. These fuel injection valves 1a to 1f are connected to the fuel pressure accumulating chamber 22 through corresponding injection pipes 21a to 21f. The fuel accumulator chamber 22 is formed in a common rail 53 extending in a row. Fuel outlets 22 a to 22 f are provided in the fuel pressure accumulation chamber 22 in the common rail 53.

A fuel pump 2 is connected to the fuel accumulator chamber 22 in the common rail 53. The fuel pump 2 includes two pumps, a first fuel pump 2a and a second fuel pump 2b. The first and second fuel pumps 2a and 2b are connected to the fuel pressure storage chamber 22 via corresponding fuel supply pipes 37a and 37b. Fuel is alternately discharged from the first and second fuel pumps 2a and 2b.

  In this fuel injection device, as can be seen from FIG. 7, the fuel injection valves 1 a to 1 f and the fuel outlets 22 a to 22 f are connected in order in the column direction via the corresponding injection pipes 21 a to 21 f. That is, the fuel injection valve 1a is connected to the fuel outlet 22a through the injection pipe 21a. Similarly, the fuel injection valve 1b, the injection pipe 21b, the fuel outlet 22b,..., The fuel injection valve 1f and the injection pipe 21f. The fuel outlets 22f are connected in this order.

  In the example of FIG. 7, the fuel introduction position of the fuel accumulator chamber 22 (the connection part of the fuel supply pipes 37a and 37b) is set between the fuel outlets 22b and 22c, and further, there is no gap between the fuel outlets 22a to 22f. Each of the injection pipes 21a to 21f is set to be equal in length by setting the pitches to be equal and reducing the distance between the fuel injection valves 1a to 1f and the fuel outlets 22a to 22f. Then, by trying to make the lengths of the respective injection pipes 21a to 21f equal, it is intended to keep the variation in the fuel injection amount low.

Japanese Patent No. 2797745 (FIG. 1)

  However, in the configuration as described in Patent Document 1 described above, the fuel introduction position of the fuel pressure accumulation chamber 22 is set between the fuel outlets 22b and 22c, and therefore, for example, the end of the fuel pressure accumulation chamber 22 (the lower end of FIG. 7). ), The fuel supply pipes 37a and 37b become longer than when the fuel introduction position is set, etc., and there is a concern that reliability may be lowered.

  Furthermore, if it is set as patent document 1, since it will be necessary to set the position of the fuel outlets 22a-22f of the fuel accumulator 22 according to the cylinder pitch of an engine, the common rail 53 becomes an engine exclusive component. End up. In this case, several types of common rails must be manufactured separately according to the shape and style of the engine, which causes a decrease in productivity and an increase in manufacturing cost.

The present invention has been made based on the above-described problems, and has an advantage that engine performance can be improved by reducing variations in fuel injection amount, and productivity and reliability of a piping structure can be improved. It aims at providing the piping structure of a fuel injection pipe.

In order to solve the above-described problems, a first engine fuel injection pipe piping structure according to the present invention includes an injection nozzle provided in each of a plurality of cylinders arranged in a row, and a fuel to be sent to the injection nozzle. In the piping structure of the engine fuel injection pipe piped between the pressure accumulating chamber (common rail), the fuel injection pipe is connected to each injection nozzle of each of the plurality of cylinders. each of the fuel injection pipe, the has a plurality of fuel outlet holes arranged side by side in the longitudinal direction of the common rail are connected to each other, before as all or part of Kifuku number of fuel injection pipe is cross each other It is characterized by being piped.

The second engine fuel injection pipe piping structure of the present invention has an injection nozzle provided in each of a plurality of cylinders arranged in a row, and the injection nozzle pressurizing fuel to be sent to each of the injection nozzles And a fuel injection pipe for an engine that is piped between the plurality of individual pumps provided for each of the plurality of individual pumps, wherein each of the injection nozzles of the plurality of cylinders has a separate fuel injection pipe. There are connected, each of the plurality of fuel injection tubes, wherein are more connected to each other in a separate pump, all or part of the fuel injection pipe before Kifuku number plumbed to cross each other It is characterized by.

According to the piping structure of the present invention, it is easy to realize the equal length of each fuel injection pipe by crossing all or part of the plurality of fuel injection pipes. As a result, variations in the fuel injection amount can be reduced, and engine performance can be improved. Such a piping structure is particularly effective for multi-injection in which injection such as pilot and pre-post is added in addition to main injection.
Furthermore, in the piping structure of the present invention, there is less need to slack in the middle of the injection pipe or to form a complicated bent shape in order to adjust the length of the fuel injection pipe. Can be improved.

In the piping structure for an engine fuel injection pipe according to the present invention, the lengths of the plurality of injection pipes may be equal or substantially equal.
In this case, by making each fuel injection pipe the same length or almost the same length, the variation in the fuel injection amount can be reduced, and the engine performance can be improved. Such a piping structure is particularly effective for multi-injection in which injection such as pilot and pre-post is added in addition to main injection.

Hereinafter, it demonstrates, referring drawings.
FIG. 1 is a plan view showing a fuel injection pipe piping structure (piping structure in the case of a common rail type) according to the first embodiment of the present invention.
2A is a schematic diagram showing a piping structure in the case of a 6-cylinder engine according to the present embodiment, and FIG. 2B is a schematic diagram showing a piping structure in the case of a conventional 6-cylinder engine.
FIG. 1 shows a cylinder head 100 having six cylinders. The cylinder heads 100a to 100f are respectively provided with fuel injection valves (injectors) 101a to 101f. The tip of each fuel injection valve 101a to 101f is an injection nozzle.

  The fuel injection valves 101a to 101f are connected to joints with nuts (simply referred to as joints) 105a to 105f in the common rail 105 extending in a row via fuel injection pipes 103a to 103f. A fuel pump 107 is connected to the common rail 105. Two fuel supply pipes 109 a and 109 b extend from the fuel pump 107. The fuel pump 107 is connected to the common rail 105 through these fuel supply pipes 109a and 109b.

  The ends of the fuel injection pipes 103a to 103f are connected by being tightened with nuts after being inserted into the joints 105a to 105f in the common rail 105, respectively. Each joint 105a-105f in the common rail 105 serves as a fuel outlet from which fuel is ejected. Here, as shown in FIGS. 1 and 2A, the fuel injection valves 101a to 101f and the joints 105a to 105f in the common rail 105 have the following correspondence relationships (1) to (6): The fuel injection pipes 103a to 103f are connected to each other.

(1) The first fuel injection valve 101a from the left in the figure is connected to the first joint 105a from the left in the figure via a fuel injection pipe 103a.
(2) The second fuel injection valve 101b from the left in the figure is connected to the fourth joint 105d from the left in the figure via the fuel injection pipe 103b.
(3) The third fuel injection valve 101c from the left in the figure is connected to the fifth joint 105e from the left in the figure via the fuel injection pipe 103c.

(4) The fourth fuel injection valve 101d from the left in the figure is connected to the second joint 105b from the left in the figure via a fuel injection pipe 103d.
(5) The fifth fuel injection valve 101e from the left in the figure is connected to the third joint 105c from the left in the figure via the fuel injection pipe 103e.
(6) The sixth fuel injection valve 101f from the left in the figure is connected to the sixth joint 105f from the left in FIG. 1 via the fuel injection pipe 103f.

  In the present embodiment, the fuel injection pipes 103b, 103c, 103d, and 103e are crossed and connected as in (2) to (5), so that all the fuel injection pipes 103a to 103f are made equal in length. It has been realized. On the other hand, as shown in FIG. 2B, when the fuel injection pipe and the common rail joint (fuel outlet) are connected in the order of # 1 to # 6 without crossing the fuel injection pipe (conventional general) However, the equal length of the fuel injection pipe cannot be easily realized.

  A numerical value is described as an example. In the case of FIG. 2A according to the present embodiment, the length of all the fuel injection pipes can be made equal to 701.0 mm, whereas in the case of FIG. # 1 and # 6 fuel injection pipes are 691.0 mm, # 2 and # 5 fuel injection pipes are 576.5 mm, # 3 and # 4 fuel injection pipes are 442.0 mm, 1 to 1.56 times Variation was confirmed in the range.

  As described above, in the present embodiment, the equalization of the fuel injection pipes 103a to 103f is realized, whereby variations in the fuel injection amount can be reduced and the engine performance can be improved. Such a piping structure is particularly effective for multi-injection in which injection such as pilot and pre-post is added in addition to main injection. Furthermore, in the present embodiment, compared to the above-described Patent Document 1 and the like, the necessity of sagging the middle of the injection pipe or forming it in a complicated bent shape is reduced. It can be improved.

Next, a second embodiment of the present invention will be described.
FIG. 3 is a plan view showing a piping structure of a fuel injection pipe according to a second embodiment of the present invention (a piping structure in the case of a row pump type).
FIG. 3 shows a cylinder head 120 having six cylinders. Each cylinder head 120 is provided with fuel injection valves (injectors) 121a to 121f. The tip of each fuel injection valve 121a to 121f is an injection nozzle. Each fuel injection valve 121a-121f is connected to each joint (fuel outlet) 125a-125f of the row | line | column type pump 125 which has an individual pump via the fuel injection pipe 123a-123f. The ends of the fuel injection pipes 123a to 123f are connected by being tightened with nuts after being inserted into the joints 125a to 125f in the row type pump 125, respectively.

  Also in the piping structure of the second embodiment, the fuel injection pipes 123b, 123c, 123d, and 123e are crossed with the same correspondence (see FIG. 2A) as the above-described (1) to (6). It is connected and equalization of all the fuel injection pipes 123a to 123f is realized. Therefore, also in this case, the variation in the fuel injection amount can be reduced, and the engine performance can be improved.

Hereinafter, an example of the piping structure of the fuel injection pipe relating to the engine cylinders of 4, 6, and 8 cylinders will be described.
4, 5 and 6 are schematic diagrams showing examples of the piping structure of the fuel injection pipe relating to the engine cylinders of 4 cylinders, 6 cylinders and 8 cylinders, respectively. In these drawings, the upper circle (circle) means the fuel injection valve, the lower square (rectangle) means the common rail or the row type pump, and the thick line between them means the fuel injection pipe. Furthermore, the numbers shall be arranged in order from the left. The fuel injection valve indicated by ○ is marked with a symbol X at the end of the number, and the fuel outlet of the common rail or row pump indicated by □ is marked with a symbol Y at the end. To distinguish.

“In the case of a 4-cylinder engine cylinder”
In the case shown in FIG. 4A, the pipes are arranged in correspondence relationships of # 1X ＃# 1Y, # 2X⇔ # 3Y, # 3X⇔ # 2Y, # 4X⇔ # 4Y. In this case, the two intermediate fuel injection pipes are crossed.
In the case shown in FIG. 4B, the pipes are connected in correspondence with # 1X⇔ # 3Y, # 2X⇔ # 4Y, # 3X⇔ # 1Y, and # 4X⇔ # 2Y. In this case, the four fuel injection pipes are crossed.

“For 6-cylinder engine cylinder”
In the case shown in FIG. 5 (A), piping is performed in a correspondence relationship of # 1X⇔ # 1Y, # 2X⇔ # 4Y, # 3X⇔ # 5Y, # 4X⇔ # 2Y, # 5X⇔ # 3Y, # 6X⇔ # 6Y. Has been. This is an example of piping similar to that shown in FIG. 2A described above, and the intermediate four fuel injection pipes are crossed.
In the case shown in FIG. 5 (B), piping is performed in correspondence with # 1X⇔ # 4Y, # 2X⇔ # 5Y, # 3X⇔ # 6Y, # 4X⇔ # 1Y, # 5X⇔ # 2Y, # 6X⇔ # 3Y. Has been. In this case, the six fuel injection pipes are crossed.

“In the case of an 8-cylinder engine cylinder”
In the case shown in FIG. 6A, # 1X１ # 1Y, # 2X⇔ # 5Y, # 3X⇔ # 6Y, # 4X⇔ # 7Y, # 5X⇔ # 2Y, # 6X⇔ # 3Y, # 7X⇔ # 4Y and # 8X⇔ # 8Y are piped in correspondence. In this case, the middle six fuel injection pipes are crossed.
In the case shown in FIG. 6B, # 1X１ # 5Y, # 2X⇔ # 6Y, # 3X⇔ # 7Y, # 4X⇔ # 8Y, # 5X⇔ # 1Y, # 6X⇔ # 2Y, # 7X⇔ # The pipes are arranged in correspondence with 3Y and # 8X８ # 4Y. In this case, the eight fuel injection pipes are crossed.

  In addition to the cases shown in FIGS. 4 to 6, it is possible to adopt another piping structure example as long as the equal length can be realized by crossing all or part of the fuel injection pipe.

  As is apparent from the above description, according to the present invention, the fuel injection for an engine having advantages such as the ability to improve the engine performance by reducing the variation in the fuel injection amount and the productivity and reliability of the piping structure. The pipe structure of the pipe can be provided.

It is a top view which shows the piping structure (piping structure in the case of a common rail type) of the fuel injection pipe which concerns on 1st Embodiment of this invention. 2A is a schematic diagram showing a piping structure in the case of a 6-cylinder engine according to the present embodiment, and FIG. 2B is a schematic diagram showing a piping structure in the case of a conventional 6-cylinder engine. It is a top view which shows the piping structure (piping structure in the case of a row | line type pump type) of the fuel injection pipe which concerns on 2nd Embodiment of this invention. It is a schematic diagram which shows the example of a piping structure of the fuel injection pipe regarding a 4-cylinder engine cylinder. It is a schematic diagram which shows the piping structural example of the fuel injection pipe regarding a 6-cylinder engine cylinder. It is a schematic diagram which shows the piping structural example of the fuel injection pipe regarding an 8-cylinder engine cylinder. 2 is a plan view of a fuel injection device disclosed in Patent Document 1. FIG.

Explanation of symbols

100, 100a to 100f Cylinder head 101a to 101f Fuel injection valve 103a to 103f Fuel injection pipe 105 Common rail 105a to 105f Joint 107 Fuel pump 109a, 109b Fuel supply pipe 120 Cylinder head 121a to 121f Fuel injection valve 123a to 123f Fuel injection pipe 125 Row type pump 125a ~ 125f Joint

Claims (3)

In a piping structure of an engine fuel injection pipe that is piped between an injection nozzle provided in each of a plurality of cylinders arranged in a row and an accumulator chamber (common rail) of fuel to be sent to the injection nozzle,
The fuel injection pipe is connected to each of the injection nozzles of the plurality of cylinders,
Each of the plurality of fuel injection pipes is individually connected to a plurality of fuel outlet holes arranged side by side in the longitudinal direction of the common rail,
Piping structure of fuel injection pipes for an engine, wherein a whole or a part of the fuel injection pipe before Kifuku number is piping to cross each other. An injection nozzle provided in each of a plurality of cylinders arranged in a row, and a row type pump having a plurality of individual pumps provided for each of the injection nozzles for pressurizing fuel to be sent to each of the injection nozzles; In the piping structure of the engine fuel injection pipe piped between
The fuel injection pipe is connected to each of the injection nozzles of the plurality of cylinders,
Each of the plurality of fuel injection pipes is individually connected to the plurality of individual pumps,
Piping structure of fuel injection pipes for an engine, wherein a whole or a part of the fuel injection pipe before Kifuku number is piping to cross each other. The piping structure of an engine fuel injection pipe according to claim 1 or 2, wherein the lengths of the plurality of injection pipes are equal or substantially equal.

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