JP2000170626A - Injection nozzle assembling seal member and fuel injection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain the temperature of a nozzle part of an injection nozzle from being increased. SOLUTION: The outer wall of this injection nozzle assembling seal member 5 is provided with a positioning part 52 extending along the inclination of a contact part formed on an engine head, and a deformation part 53 extending from the end on the small diameter part of the positioning part 52 and having the taper rate smaller than that of the seal surface. An axially extending nozzle hole 51 having the inside diameter larger than the outside diameter of a nozzle part 33 of the injection nozzle is formed on the injection nozzle assembling seal member 5. The injection nozzle assembling seal member 5 is pressed against the side to be contact until the positioning surface 52 and the part to be contact are brought into contact with each other to deform the deformation part 53 along the inclination of the part to be contact and to radially narrow the nozzle hole 51, and an inner contact part 54 and the outer wall of the nozzle part 33 are bonded to each other. Therefore, the inflow of combustion gas from a combustion chamber is shut off by the inner contact part 54, and the nozzle part 33 can be cooled by fuel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seal member for assembling an injection nozzle and a fuel injection device, and more particularly, to combustion from an engine head of an internal combustion engine (hereinafter referred to as "engine") and an injection hole at a tip end of a nozzle portion. TECHNICAL FIELD The present invention relates to a seal member for assembling an injection nozzle and a fuel injection device that improve sealing performance with an in-cylinder injection type injection nozzle that directly injects fuel into a room.

[0002]

2. Description of the Related Art Diesel engines and direct-injection gasoline engines are known as engines for directly injecting fuel into a combustion chamber. It is known that in a diesel engine, NOx contained in exhaust gas can be reduced by optimizing the length of the injection nozzle tip of the injection nozzle projecting into the combustion chamber. With the recent tightening of exhaust gas regulations, the length of the tip of the injection nozzle protruding into the combustion chamber has increased.

[0003]

However, the longer the tip of the nozzle portion of the injection nozzle projects into the combustion chamber, the higher the temperature tends to be due to the combustion gas. When the temperature of the tip of the nozzle portion exceeds a predetermined temperature, the nozzle portion is annealed, the material strength is reduced, and the nozzle portion is damaged. In addition, it is assumed that the injection accuracy of the injection nozzle is reduced because the volatile component of the fuel attached near the injection hole evaporates before ignition, and the remaining gum component is carbonized by heat and carbon is deposited near the injection hole. . Therefore, in order to protrude the tip of the nozzle portion into the combustion chamber for a long time, it is necessary to enhance the function of cooling the injection nozzle.

On the other hand, since the improvement of the cooling function provided in the engine head such as a water jacket involves a drastic design change, if the cooling function provided in the engine head is improved to cool the injection nozzle, the manufacturing cost of the engine is reduced. And the product development period is prolonged.

SUMMARY OF THE INVENTION The present invention has been made to solve this problem, and it is an object of the present invention to provide an injection nozzle assembling seal member and a fuel injection device which have a simple structure and suppress a rise in the temperature of a nozzle portion of the injection nozzle. With the goal.

[0006]

According to the seal member for assembling the injection nozzle according to the first aspect of the present invention or the fuel injection device according to the fifth aspect, the annular main body has an outer diameter larger than the small diameter portion. Therefore, it has an outer wall surface that comes into contact with the contacted portion and is pressed against the contacted portion so as to be in airtight contact with the contacted portion. No combustion gas escapes. Furthermore, since the inner diameter is increased or decreased at the time of assembling, the inner wall is in air-tight contact with the outer wall of the nozzle portion after assembling, so that the combustion gas flowing out of the combustion chamber is supplied to the injection nozzle assembling seal member and the nozzle portion. There is no direct heating of the side opposite to the combustion chamber from the nozzle portion of the injection nozzle through the gap in the outer wall. Therefore, the temperature of the fuel flowing into the nozzle portion is close to the normal temperature, and the fuel near the normal temperature flows through the nozzle portion, thereby cooling the nozzle portion, thereby suppressing a rise in the temperature of the nozzle portion.

According to the seal member for assembling the injection nozzle according to the second aspect of the present invention, the inner contact portion having an inner diameter smaller than the outer diameter of the nozzle portion is expanded by the nozzle portion at the time of assembling, so that the inner contact portion after the assembling is completed. The contact portion and the outer wall of the nozzle portion are in airtight contact with each other, and the combustion gas is blocked by the nozzle portion and the seal member for assembling the injection nozzle.

According to the seal member for assembling the injection nozzle according to the third aspect of the present invention, the inner wall is a portion having an inner diameter larger than the outer diameter of the nozzle portion, and after assembling, it burns from the inner contact portion. Since it has a non-contact portion located on the opposite side of the chamber, manufacture and assembly are easy.

According to the seal member for assembling the injection nozzle according to the fourth aspect of the present invention, the main body has at one end a cylindrical heat radiating portion made of metal having higher thermal conductivity than the nozzle portion, and the heat radiating portion has a small diameter. Since it is inserted into the portion, the area of the portion that conducts heat from the nozzle portion to the engine head can be increased, and the heat of the nozzle portion can be easily released to the engine head. Therefore, a rise in the temperature of the nozzle portion can be further suppressed.

According to the fuel injection device of the present invention, the outer wall has the deformed portion and the positioning portion. When the sealing member for assembling the injection nozzle is pressed by the pressing means until the positioning portion contacts the contacted portion, the outer wall is distorted along the tapered surface of the contacting portion because the contacted portion has a tapered surface. As a result, the outer diameter is reduced, and the inner wall is brought into air-tight contact with the outer wall of the nozzle portion. Accordingly, the combustion gas is shut off by the nozzle portion and the seal member for assembling the injection nozzle.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention; (First Embodiment) FIG. 1 shows a structure in which a seal member for assembling an injection nozzle according to a first embodiment of the present invention is attached to an engine head of a diesel engine.

An injection nozzle mounting hole 2 for accommodating the injection nozzle 3 accommodated in the injection nozzle holder 4 as a pressing means is formed for each combustion chamber 7 in the aluminum alloy engine head 1 formed by casting. Is done. The injection nozzle mounting hole 2 has a large-diameter portion 21 on the opposite side of the combustion chamber 7 and a tapered abutted portion 22 that forms a predetermined angle with the axis of the injection nozzle 3 and narrows at a constant inclination from the large-diameter portion 21. And a substantially cylindrical small-diameter portion 23 into which the nozzle portion 33 is inserted with a predetermined radial clearance.

The injection nozzle 3 is housed in a steel injection nozzle holder 4 and is mounted on the injection nozzle mounting hole 2. The outer diameter of the injection nozzle 3 increases in the order of the nozzle portion 33, the stepped portion 32, and the nozzle body 31, and an injection hole 34 is formed at the tip of the nozzle portion 33. When the nozzle body 31 is inserted until it comes into contact with the positioning step 41, the stepped portion 32 and the nozzle body 31 are housed in the ejection nozzle holder 4, and the nozzle portion 33 protrudes from one end of the ejection nozzle holder 4.
When the injection nozzle 3 is housed in the injection nozzle holder 4 and attached to the engine head 1, the nozzle portion 33
Protrude into. A fuel reservoir (not shown) is formed inside the nozzle body 31, and a fuel passage and a valve seat are formed inside the nozzle portion 33. The injection nozzle 3 injects fuel directly from the injection hole 34 into the combustion chamber 7 when the valve member (not shown) separates from the valve seat, and shuts off the flow of fuel when the valve member sits on the valve seat.

A seal member 5 for assembling the injection nozzle is installed in a gap in the axial direction between the injection nozzle holder 4 and the abutted portion 22. The injection nozzle assembling seal member 5 is formed by pressing the injection nozzle holder 4 into the contacted part 22 side and fixing the injection nozzle holder 4 to the engine head 1 to thereby form the contacted part 22 and the injection nozzle holder 4.
And closes out of the combustion gas from the combustion chamber 7 to the outside of the engine head 1.

The seal member 5 for assembling the injection nozzle is made of a material having high thermal conductivity such as copper, and has an annular shape whose outer wall surface has a substantially truncated cone shape as shown in FIG. The inclination angle of the outer wall surface of the injection nozzle assembling seal member 5 changes in the middle thereof. Positioning portion 52 on the large diameter side of seal member 5 for assembling injection nozzle
The angle θ2 between the outer surface and the axis of the injection nozzle 3 is
The angle formed by 2 and the axis of the injection nozzle 3 is the same. The angle θ1 between the outer surface of the deformed portion 53 on the small diameter side of the seal member 5 for assembling the injection nozzle and the axis of the injection nozzle holder 4 is determined by the contact portion 22
Is smaller than the angle formed by the axis of the injection nozzle 3 and the axis of the injection nozzle 3. θ1 is determined by the shape of the abutted portion 22, and it is not always necessary that θ1 be smaller than θ2 as in the present embodiment. The seal member 5 for assembling the injection nozzle has a nozzle hole 51 penetrating in the axial direction and having an inner diameter slightly larger than the outer diameter of the nozzle portion 33.

When assembling the injection nozzle 3 to the engine head 1, the injection nozzle 3 accommodated in the injection nozzle holder 4
Is inserted into the nozzle hole 51 of the injection nozzle assembling seal member 5, the injection nozzle holder 4 is inserted into the large-diameter portion 21, and a bolt (not shown) is used until the positioning portion 52 comes into contact with the contacted portion 22. The injection nozzle holder 4 is press-fitted and fixed to the engine head 1. Positioning part 5 in contact part 22
When the seal member 5 for assembling the injection nozzle is pressed against the contacted portion 22 until the contact portion 2 comes into close contact, the deformed portion 53 becomes
2 and inwardly in contact with the abutted portion 22 so as to narrow the nozzle chamber 51 side of the combustion chamber 7. Nozzle hole 5
When the side of the first combustion chamber 7 is narrowed, the inner contact portion 54 raised by deformation and the outer wall of the nozzle portion 33 are brought into annular contact with each other as shown in FIG.

The operation of the injection nozzle assembling seal member 5 having the above configuration will be described below. When the diesel engine is driven, fuel is directly injected from the injection holes 34 into the combustion chamber 7 at a predetermined timing, and the fuel is mixed with air in the combustion chamber 7 to generate a mixture having a predetermined air-fuel ratio. The air-fuel mixture is ignited and burned by being compressed by a piston in a cylinder (not shown), and the combustion gas expands to move the piston. When the combustion gas expands, the combustion gas flows out of the combustion chamber 7 through a gap between the small diameter portion 23 and the nozzle portion 33. The combustion gas flowing out of the combustion chamber 7 is blocked by the contact portion between the contacted portion 22 of the engine head 1 and the deformed portion 53 of the gasket and the contact portion between the nozzle portion 33 and the inside contact portion 54 of the nozzle hole 51. You.

(Comparative Example) FIG. 6 shows a comparative example of a conventional general seal member for assembling a spray nozzle in which the inclination angle of the outer wall is the same as the inclination angle of the contacted portion and is constant. Parts substantially the same as those in the first embodiment are denoted by the same reference numerals. Before assembling, the inclination angle of the outer wall of the injection nozzle assembling seal member 8 is the same and constant as the inclination angle of the abutted portion 22, and the nozzle hole 81 is formed.
In order to insert the nozzle portion 33 into the nozzle hole 81 and the nozzle portion 33, a predetermined radial clearance is provided. Even if the outer wall is pressed against the abutted portion 22, the seal member 8 for assembling the injection nozzle is not substantially deformed, so that the clearance L shown in FIG. Therefore, the combustion gas flowing out of the combustion chamber 7 through the gap between the nozzle portion 33 and the small-diameter portion 23 flows through the nozzle hole 81 and the nozzle portion 3.
3 to the stepped portion 32 and the bottom surface of the nozzle body 31.

Here, a comparison is made between the diesel engine with the seal member 5 for assembling the injection nozzle according to the first embodiment and the diesel engine with the seal member 8 for assembling the injection nozzle according to the comparative example. The diesel engine with the injection nozzle assembling seal member 8 according to
The combustion gas flows into the stepped portion 32 of the injection nozzle 3 and the bottom surface of the nozzle body 31. Therefore, the fuel inside the stepped portion 32 and the inside of the nozzle body 31 is heated, and the nozzle body 3
The temperature of the fuel flowing from 1 into the nozzle portion 33 becomes high. Therefore, the effect of the fuel cooling the nozzle portion 33 is small. on the other hand,
In the diesel engine to which the injection nozzle assembling seal member 5 according to the first embodiment is attached, the stepped portion 32 and the bottom surface of the nozzle body 31 are not directly heated by the combustion gas. It is difficult for the fuel to become hot. Therefore, the fuel flowing from the nozzle body 31 into the nozzle portion 33 is close to room temperature, and cools the nozzle portion 33 while flowing through the nozzle portion 33. As a result, the first
In the diesel engine to which the injection nozzle assembling seal member 5 according to the embodiment is attached, the fuel cools the nozzle portion 33, so that the temperature rise of the nozzle portion 33 can be suppressed by a simple configuration.

On the other hand, if the temperature of the nozzle portion 33 becomes high and is annealed, the material strength is reduced. If the nozzle portion 33 is made to protrude long into the combustion chamber 7 in order to cope with recent emission gas regulations, As shown in the comparative example, the fuel
Is not cooled, it is necessary to take measures such as improving the water jacket around the injection nozzle 3. However, there is a problem that the improvement of the water jacket causes an increase in engine manufacturing cost and a prolonged product development period. The diesel engine having the injection nozzle assembling seal member 5 according to the first embodiment solves this problem by devising the shape of the injection nozzle assembling seal member 5. In other words, the seal member 5 for assembling the injection nozzle according to the first embodiment makes it possible to manufacture an engine with a low manufacturing cost and a short product development period.

(Second Embodiment) FIG. 4 shows a structure in which a seal member for mounting an injection nozzle according to a second embodiment of the present invention is mounted on an engine head of a diesel engine. Parts substantially the same as those in the first embodiment are denoted by the same reference numerals. The small-diameter portion 23 formed in the engine head 1 has a concave wall surface on the side of the contacted portion 22, and a cooling surface 24 is formed.

FIG. 5 shows the injection nozzle assembling seal member 6 provided in the axial gap between the abutted portion 22 and the injection nozzle holder 4. The seal member 6 for assembling the injection nozzle is made of a material having a high thermal conductivity such as copper, and has an annular wall-shaped main body 61 whose outer wall surface has a substantially frustoconical shape and a substantially cylindrical heat-radiating portion 62, and penetrates in the axial direction. It has a nozzle hole 63. The inclination angle of the outer wall 64 of the main body 61 is the same as the inclination angle of the abutted portion 22. The inner wall of the nozzle hole 63 on the main body 61 side is the nozzle portion 33.
Has a non-contact portion 67 having an inner diameter slightly larger than the outer diameter of the non-contact portion. The end of the heat radiating portion 62 on the side of the injection hole 34 is bent inward, and the inner wall of the bent portion has an inner diameter of the nozzle portion 33.
The inner contact portion 66 is slightly smaller than the outer diameter of the inner contact portion. The outer diameter of the heat radiating portion 62 is slightly smaller than the inner diameter of the small diameter portion 23 on the cooling surface 24. The heat radiating surface 65 which is the outer wall of the heat radiating portion 62
Faces the cooling surface 24 when the injection nozzle 3 is fixed at a predetermined position as described later.

When the injection nozzle 3 is mounted on the engine head 1, the injection nozzle 3 accommodated in the injection nozzle holder 4
Is inserted into the nozzle hole 63 of the injection nozzle assembling seal member 6, the injection nozzle holder 4 is inserted into the large diameter portion 21, and bolts (not shown) are used until the outer wall 64 is in close contact with the contacted portion 22. The injection nozzle holder 4 is press-fitted and fixed to the engine head 1. Since the inner diameter of the inner contact portion 66 is smaller than the outer diameter of the nozzle portion 33, when the nozzle portion 33 passes through the nozzle hole 63, the inner contact portion 66 is pushed outward and is in annular contact with the outer wall of the nozzle portion 33.

The sealing member 6 for assembling the injection nozzle with the above-described structure allows the combustion gas flowing out of the combustion chamber 7 through the gap between the small-diameter portion 23 and the nozzle portion 33 to the close contact portion between the inner contact portion 66 and the nozzle portion 33. Cut off. Therefore, the injection nozzle 3
Is not heated by the combustion gas on the side opposite to the injection hole from the contact portion. Therefore, the nozzle body 33 moves from the nozzle body 31 to the nozzle 33.
The temperature of the fuel flowing into the nozzle portion is close to room temperature, and cools the nozzle portion 33 while flowing through the inside of the nozzle portion 33. Further, the heat of the nozzle portion 33 heated by the combustion gas is transmitted to the nozzle portion 3.
3 and the sealing member 6 for assembling the injection nozzle through the contact portion
To the engine head 1 from the heat dissipation surface 65 and the outer wall 64.

Accordingly, according to the seal member 6 for assembling the injection nozzle according to the second embodiment, the fuel flowing through the nozzle portion 33 cools the nozzle portion 33, and the heat of the nozzle portion 33 easily escapes to the engine head 1. In addition, it is possible to suppress a rise in the temperature of the nozzle portion 33. In this embodiment, the radiator 6
2 is shorter than the axial length of the small diameter portion 23,
The heat radiating portion 62 may cover the nozzle portion 33 up to the vicinity of the injection hole 34 and be exposed in the combustion chamber 7.

[Brief description of the drawings]

FIG. 1 is a partially cutaway sectional view showing an assembly structure of a seal member for assembling an injection nozzle according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a seal member for assembling the injection nozzle before assembling according to the first embodiment of the present invention.

FIG. 3 is a partially cutaway cross-sectional view showing the injection nozzle assembling seal member after assembly according to the first embodiment of the present invention.

FIG. 4 is a partially cutaway sectional view showing an assembly structure of an injection nozzle assembling seal member according to a second embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a seal member for assembling an injection nozzle before assembling according to a second embodiment of the present invention.

FIG. 6 is a partially cutaway sectional view showing a structure for assembling a conventional seal member for assembling an injection nozzle.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine head 2 Injection nozzle mounting hole 3 Injection nozzle 4 Injection nozzle holder (pressing means) 5, 6 Injection nozzle assembling member 7 Combustion chamber 21 Large diameter portion 22 Contact portion 23 Small diameter portion 33 Nozzle portion 34 Injection Hole 53 Deformed part 54, 66 Inner contact part 64 Outer side wall 62 Heat radiator 67 Non-contact part

Claims (6)

[Claims] 1. A sealing member for assembling an injection nozzle, which is formed in an engine head of an internal combustion engine and is inserted into an injection nozzle mounting hole for accommodating the injection nozzle, wherein an inner wall of the injection nozzle mounting hole is located on a combustion chamber side. A small-diameter portion, a large-diameter portion on the opposite side of the combustion chamber, and a contact portion between the small-diameter portion and the large-diameter portion, wherein the injection nozzle includes a nozzle portion housed in the small-diameter portion and the large-diameter portion. An annular body having a body portion accommodated in the diameter portion, having an outer diameter larger than the small diameter portion, and accommodated in an axial gap between the abutted portion and the outer wall of the body portion; An outer wall that is in airtight contact with the abutted portion by being pressed against the abutted portion, and an inner diameter that expands or contracts at the time of assembling so that the outer wall of the nozzle portion is in airtight contact after assembling. And an inner wall that performs Seal member for with Le set. 2. The inner wall is a portion having an inner diameter smaller than the outer diameter of the nozzle portion, and is expanded by the nozzle portion at the time of assembling so that the inner wall is airtight with the outer wall of the nozzle portion after assembling. The seal member for assembling an injection nozzle according to claim 1, wherein the seal member has an inner contact portion that makes contact. 3. The method according to claim 2, wherein the inner wall has a non-contact portion which is a portion having an inner diameter larger than an outer diameter of the nozzle portion and which is located on a side opposite to the combustion chamber from the inner contact portion after assembly. The seal member for assembling an injection nozzle according to claim 2. 4. The method according to claim 1, wherein the main body has at one end a cylindrical heat radiating portion made of a metal having higher thermal conductivity than the nozzle portion, and the heat radiating portion is inserted into the small diameter portion after assembly. The injection nozzle assembling seal member according to any one of claims 1, 2 and 3, wherein 5. An injection nozzle mounting hole is formed, and an inner wall of the injection nozzle mounting hole has a small-diameter portion on the combustion chamber side, a large-diameter portion on the opposite side of the combustion chamber, and a portion between the small-diameter portion and the large-diameter portion. An engine head having an abutted portion, an injection nozzle having a nozzle portion accommodated in the small-diameter portion and a body portion accommodated in the large-diameter portion, and an outer wall having an outer diameter larger than the small-diameter portion. Has an annular main body opposed to the abutted portion, is housed in an axial gap between the abutted portion and the outer wall of the body portion, and the outer wall of the nozzle portion and the outer wall of the nozzle portion are distorted during assembly. A sealing member for assembling an injection nozzle that hermetically contacts an inner wall of the main body; and a sealing member for assembling the injection nozzle is pressed against the abutted portion, and the abutted portion and the outer wall are hermetically sealed. And a pressing means for contacting the fuel injection device. 6. The contacted portion has a tapered surface, the outer wall is deformed by being pressed against the tapered surface during assembly, and the contacted portion is deformed by deforming the deformed portion. 6. The fuel injection device according to claim 5, further comprising a positioning portion that abuts against the fuel injection valve.