JP2000320425A - Fuel injection device for two-cycle multicylinder direct injection engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel injection device for a two-cycle multi-cylinder direct injection engine which can prevent damage to a fuel piping and injector due to the vibration of the engine. SOLUTION: A fuel piping 9 is constituted by two headers 9A, 9B, connected respectively to the fuel supply ports of two injectors provided on two cylinder blocks 1A, 1B of an engine respectively and a connection pipe line 90 for connecting the headers 9A, 9B connected to the fuel supply ports of adjacent injectors with each other. The connection pipe line 90 is formed into a shape, having a bent part 91 bent so as to form V letter shape and the top 91a of this bent part is arranged in the state of being directed toward the connection surfaces A, B ides of the cylinder blocks 1A, 1B of the engine with the cylinder heads 3A, 3B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection device used for a two-cycle multi-cylinder direct injection engine.

[0002]

2. Description of the Related Art A fuel injection device used in a two-cycle or more two-cycle multi-cylinder gasoline direct injection engine includes a plurality of in-cylinder direct injection injectors provided for a plurality of cylinders of the engine, a fuel pump, and a fuel pump. A fuel pipe for distributing the fuel discharged by the fuel pump to the fuel supply ports of the plurality of in-cylinder direct injection injectors, and a fuel pipe for each cylinder to inject a predetermined amount of fuel from the injector for each cylinder at a predetermined injection timing. An injector control device for applying a drive current to a solenoid of the injector.
An injector provided for each cylinder is attached to a cylinder head of the engine and injects fuel directly into each cylinder (combustion chamber).

[0003] As a direct injection injector for a two-cycle multi-cylinder direct injection engine, a top feed type injector which has been used in a four-cycle gasoline engine and has already been used is widely used.

FIGS. 2 and 3 show, as an example, a state in which an in-cylinder direct injection injector is attached to a two-cylinder two-stroke engine. FIG. 2 is a side view of the engine, and FIG. 3 is a cylinder head of the engine. It is sectional drawing of a part.

In FIG. 2, reference numerals 1A and 1B denote first and second cylinder blocks mounted on the upper portion of the crankcase 2, respectively, and 3A and 3B denote first and second cylinder blocks, respectively.
The first and second cylinder heads 4 mounted on the upper portions of the cylinder blocks 1A and 1B are crankshafts supported by the crankcase 2. FIG. 3 is a sectional view of the first cylinder head 3A. The first cylinder head 3A has a first cylinder head 3A provided for the first cylinder.
And a first in-cylinder direct injection injector 6A provided for the first cylinder.

[0006] The first injector 6A has an injection port 601A at the tip and an injector body 6 having a tubular fuel connector 602A at the rear end to which the fuel pipe 9 is connected.
03A, a needle valve 604A for opening and closing the injection port 601A in the injector body, and a solenoid (not shown) disposed in the injector body for driving the needle valve 604A. An electric connector 605A for connecting an electric wire 7A for applying a drive current to the solenoid is protruded from a side surface near a rear end of the body 603A.

[0007] The injector 6A has an injection port 601A.
Is attached to the cylinder head 3A in a state facing the combustion chamber 8A in the first cylinder of the engine, and a fuel supply port provided at a shaft portion of a fuel pipe 9 and a fuel connector 602A from a fuel pump (not shown). The fuel is supplied at a predetermined pressure into the injector body 603A through the fuel cell.

Although not shown, the second cylinder head 3
B is provided with a second spark plug 5B and a second in-cylinder direct injection injector 6B formed similarly to the first injector 6A.

As shown in FIG. 2, the fuel pipe 9 conventionally used is formed from a pipe formed so as to extend linearly across the first cylinder block 1A and the second cylinder block 1B. The profile shape of the cross section is set to a shape in which a semi-circular arc is attached to one end of the rectangle in the longitudinal direction.

A fuel passage 901 extending in the longitudinal direction is provided inside the fuel pipe 9, and a first passage communicating with the fuel passage 901 is provided.
And second injector connection holes 902A and 902B
(902B is not shown), and the fuel connectors of the injectors 6A and 6B are connected to the first and second injector connection holes 902A and 902B, respectively.

The in-cylinder direct injection injector used in the direct injection engine has a normal fuel pressure as high as 5 to 12 [MPa]. Therefore, as the fuel pipe 9, a relatively lightweight and high-strength drawing pipe (cold forging) is used. Pipe) is used, and the entire pipe 9 connecting the plurality of injectors is integrally formed.

As shown in FIG. 2, the fuel pipe 9 is fixed to and supported by pipe stays 10A and 10B attached to the cylinder heads 3A and 3B of the engine by bolts 11, respectively. Connected to the outlet of the fuel pump.

The injectors 6A and 6B are provided with injection ports 601A and 601B while a drive current is applied to respective solenoids from an injector control device (not shown).
(601B is not shown) and fuel is directly injected into the combustion chambers in the first cylinder and the second cylinder of the engine.

[0014]

As described above, in a two-cycle multi-cylinder engine having an independent cylinder block, relatively large deformation occurs due to the explosion pressure of a cylinder in the explosion stroke. With no cylinder, little deformation occurs. For this reason, the relative displacement generated between the cylinders increases, and a large distortion occurs in the fuel pipe connecting the injectors.

FIG. 4 is an exaggerated view of a conventional two-cycle multi-cylinder direct injection engine in which the fuel pipe is distorted due to the deformation of the cylinder. Conventional 2
In the cycle multi-cylinder direct injection engine, since the distortion shown in FIG. 4 is repeatedly generated in the fuel pipe 9 with the rotation thereof, when the use period is long, the concentration of the stress a in the illustrated arrow a is likely to occur. There is a possibility that the fuel pipe 9 may be broken at a portion to cause fuel leakage, a crack may be formed at a portion where the stress concentration of the injector is likely to occur, a fuel leak may occur, or the stay may be broken at a portion indicated by an arrow b in the drawing. Was.

FIG. 2 shows a two-cycle multi-cylinder engine.
As shown in the above, not only the cylinder block and the cylinder head are independent, but also the cylinder block is provided independently, and the cylinder head is commonly provided for a plurality of cylinder blocks. The same problem as described above occurs when a plurality of cylinder blocks are independently provided and a cylinder head is commonly provided.

An object of the present invention is to prevent a fuel pipe for distributing fuel to an injector provided for each of a plurality of cylinders from being damaged by vibration of an engine or an injector from being damaged by distortion given through the fuel pipe. It is an object of the present invention to provide a fuel injection device for a two-cycle multi-cylinder direct injection engine, which is capable of preventing the above problem.

[0018]

SUMMARY OF THE INVENTION The present invention comprises a plurality of in-cylinder direct injection injectors provided for each of a plurality of cylinders of a two-cycle multi-cylinder direct injection engine having a plurality of cylinders. The present invention relates to a fuel injection device for a two-cycle, multi-cylinder direct injection engine having a fuel pipe for distributing fuel discharged from a fuel pump to a fuel supply port of an injector. This prevents the piping from being damaged and the injector from being damaged.

According to the present invention, of the fuel pipe sections, the connecting pipe section that connects between the injectors attached to the cylinders adjacent to the engine is provided with a convex shape on the joint surface side between the cylinder block and the cylinder head. A curved portion was provided.

In a preferred aspect of the present invention, the fuel pipe includes a plurality of header portions connected to respective fuel supply ports of a plurality of injectors provided for a plurality of cylinders, and a fuel supply port of an adjacent injector. It is formed in a shape having a connecting pipe portion connecting between header portions respectively connected to the ports. Each connecting pipe section is formed in a shape having a curved portion curved to exhibit a U-shape or a V-shape, and a vertex of the curved portion is directed toward a joint surface side of the cylinder block and the cylinder head of the engine. It is arranged in the state that it was.

When the displacement of the injector mounting surface of the two-cycle multi-cylinder engine during operation was examined, the amount of displacement in the direction substantially perpendicular to the joint surface between the cylinder head and the cylinder block during the explosion-expansion stroke was the largest. It turned out to be big. The injector mounting surface oscillates about the crankshaft as the center of rotation, and it was revealed that the vibration acceleration of the injector was maximized at the fuel supply port.

As described above, when the connecting pipe portion of the fuel pipe connecting between the adjacent injectors has a shape having a convex curved portion on the joint surface side between the cylinder block and the cylinder head, the connecting pipe portion is The elasticity of the connecting pipe allows the relative displacement occurring between adjacent cylinder blocks to be absorbed by the curved portion of the connecting pipe section, resulting in a large concentration of stress in a specific portion of the fuel pipe and the injector. Can be prevented.

When the fuel pipe is formed as described above, the weight of the fuel pipe increases, but the curved portion of the connecting pipe section is formed to have a convex shape toward the joint surface between the cylinder block and the cylinder head. By moving the center of gravity of the fuel pipe in the direction of reducing the vibration acceleration and reducing the stress generated in the fuel pipe and the injector, the relative displacement between adjacent cylinders can be absorbed by the curved portion of the fuel pipe. In addition to the above, it is possible to prevent an excessive force from being applied to the fuel pipe and the injector, and it is possible to effectively prevent the fuel pipe and the injector from being damaged.

[0024]

FIG. 1 shows a main part (fuel pipe portion) of a fuel injection device according to the present invention together with an engine. In FIG. 1, the same parts as those in the conventional example shown in FIGS. 2 and 3 are shown. Are given the same reference numerals.

In the example shown in FIG. 1, the fuel pipe 9 is
And second injectors 6A and 6A provided for the first and second cylinder blocks 1A and 1B, respectively.
B (not shown in FIG. 1), a plurality of header portions 9A and 9B connected to respective fuel supply ports, and a header portion 9A.
And 9B. The connecting pipe portion 90 is formed in a shape having a curved portion 91 which is curved so as to exhibit a V-shape, and a vertex 91a of the curved portion is connected to the cylinder blocks 1A, 1B of the engine.
In a state perpendicular to the joining surfaces A and B of the cylinder heads 3A and 3B (the bending portion 91 is connected to the joining surfaces A and 3B).
B) (located on a plane perpendicular to B).

Each of the header portions 9A and 9B is formed of a drawn pipe similarly to the fuel pipe used in the conventional example, and the cross-sectional shape thereof is a semicircular arc shape at one end in the longitudinal direction of the rectangle. The shape is set with.

A fuel passage (corresponding to fuel passage 901 in FIG. 3) is provided inside each of header portions 9A and 9B.
And an injector connection hole (corresponding to the hole 902A in FIG. 3) into which the fuel connector of the corresponding injector is fitted and connected.

The headers 9A and 9B are fixed by appropriate means to stays 10A and 10B attached to the cylinder heads 3A and 3B, respectively.
A and 6B are connected to the fuel connectors.

The illustrated connecting pipe section 90 is formed by molding a drawn pipe having a circular cross section, and has a curved section 91 having a V-shape and straight pipe sections 92A and 92B extending in opposite directions from both ends thereof. The straight pipe portion 92A,
92B are connected to the header sections 9A and 9B, respectively.

The other points are the same as those of the prior art shown in FIGS.

When the connecting pipe portion 90 of the fuel pipe 9 is formed into a shape having the curved portion 91 as described above, the connecting pipe portion 9 is formed.
0 can be made elastic so that its deformation can be facilitated. Therefore, the relative displacement generated between adjacent cylinder blocks is absorbed by the curved portion of the communication pipe portion, and the specific portion of the fuel pipe and the injector is specified. Large stress concentration can be prevented.

When the curved portion 91 of the connecting pipe portion of the fuel pipe is formed to be convex toward the joint surface between the cylinder block and the cylinder head, the center of gravity of the fuel pipe is moved in a direction to reduce the vibration acceleration of the fuel pipe 9. Thus, the stress generated in the fuel pipe and the injector with the operation of the engine can be reduced. Therefore, combined with the fact that the relative displacement between the adjacent cylinders can be absorbed by the curved portion of the fuel pipe, it is possible to prevent an excessive force from being applied to the fuel pipe and the injector. Can be prevented from being damaged.

In the above example, two cycles 2 in which both the cylinder head and the cylinder block are provided independently
Although the present invention has been applied to a cylinder engine, the present invention can be applied to a case where a cylinder head is commonly provided for a plurality of independently provided cylinder blocks.

In the above example, a two-cycle two-cylinder direct injection engine is taken as an example. However, the present invention can be applied to a fuel injection device used for a three-cylinder or more two-cycle multi-cylinder direct injection engine. Of course.

In the above example, the connecting pipe section 90 of the fuel pipe is used.
Is formed in a V-shape, but the connecting pipe portion 90 of the fuel pipe may have any shape as long as it is convex on the joint surface side between the cylinder block and the cylinder head, and need not necessarily be V-shaped. Absent. For example, the curved portion 91 may be U-shaped, and may be arranged with its apex facing the joint surface between the cylinder block and the cylinder head.

In the present invention, as described above, it is preferable that the apex of the curved portion of the connecting pipe portion of the fuel pipe be oriented in a direction perpendicular to the joint surface between the cylinder block and the cylinder head. The direction in which the vertex of the curved portion of the road portion is directed may be slightly shifted from a direction perpendicular to the joint surface between the cylinder block and the cylinder head.

[0037]

As described above, according to the present invention, the connecting pipe portion of the fuel pipe connecting between the adjacent injectors is
Since the connecting pipe section has elasticity as a shape having a convex curved portion on the joining surface side of the cylinder block and the cylinder head, the relative displacement generated between adjacent cylinder blocks can be reduced by the connecting pipe section. The absorption by the curved portion can prevent a large concentration of stress from being generated in a specific portion of the fuel pipe and the injector. In addition, the connecting pipe section of the fuel pipe is formed in a convex shape on the joint surface side of the cylinder block and the cylinder head, so that the center of gravity of the fuel pipe is moved in a direction to reduce the vibration acceleration of the fuel pipe, and the fuel pipe and Since the stress generated in the injector can be reduced, a relative displacement generated between adjacent cylinders can be absorbed by the curved portion of the fuel pipe, and an excessive force is applied to the fuel pipe and the injector. Can be prevented, and damage to the fuel pipe and the injector can be effectively prevented.

[Brief description of the drawings]

FIG. 1 is a side view showing a main part of a fuel injection device according to the present invention together with a main part of an engine.

FIG. 2 is a side view showing a main part of a conventional fuel injection device together with a main part of an engine.

FIG. 3 is a sectional view of a cylinder head of the engine shown in FIG. 2;

FIG. 4 is an exaggerated side view showing a state in which a fuel pipe is distorted in a conventional two-cycle two-cylinder engine.

[Explanation of symbols]

1A, 1B: cylinder block, 3A, 3B: cylinder head, 9: fuel pipe, 9A, 9B: header, 90 ...
Connecting pipe section, 91: curved section, 10A, 10B: stay.

Claims (2)

[Claims] 1. A plurality of in-cylinder direct injection injectors provided for each of a plurality of cylinders of a two-cycle multi-cylinder direct injection engine having a plurality of cylinders, and a fuel pump provided at a fuel supply port of the plurality of injectors. A fuel injection device for a two-cycle multi-cylinder direct injection engine, comprising: a fuel pipe for distributing fuel to be discharged by the fuel pipe; wherein the fuel pipe is connected to a portion connecting injectors attached to adjacent cylinders of the engine. A fuel injection device for a two-cycle multi-cylinder direct injection engine, characterized by having a curved portion which is curved in a convex shape on the joint surface side of a cylinder block and a cylinder head of an engine. 2. A plurality of injectors for in-cylinder direct injection provided for each of a plurality of cylinders of a two-cycle multi-cylinder direct injection engine having a plurality of cylinders, and a fuel pump provided at a fuel supply port of the plurality of injectors. A fuel injection device for a two-cycle multi-cylinder direct injection engine, comprising: a fuel pipe for distributing a fuel discharged from the fuel tank; wherein the fuel pipe supplies fuel to a plurality of injectors provided to the plurality of cylinders, respectively. A plurality of header portions connected to the ports, and a connecting pipe portion connecting between the header portions respectively connected to the fuel supply ports of the adjacent injectors, wherein the connecting pipe portion is U-shaped or V-shaped. The engine is formed in a shape having a curved portion curved so as to have a character shape, and a vertex of the curved portion is formed at a cylinder block and a cylinder head of the engine. Fuel injection device for a two-cycle multiple cylinder direct injection engine, characterized in that the are arranged in a state of facing the bonding surface side.