JP2000009000A - Mounting structure of injector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce noises of an engine so as to improve quietness, by constituting so that a tip end portion of an injector is elastically supported, through a seal member, by a mounting hole opening to a combustion chamber, and so that a rear end of the injector is elastically supported, through a delivery pipe, by an engine body. SOLUTION: Firstly, on a sidewall face of a cylinder head 3 located in an upper portion on an engine body side, a delivery pipe 14 for fuel supply is opposedly placed to be long in a longitudinal direction of the cylinder head 3. The delivery pipe 14 has two arms 142 fixed to each mounting portion 13 of the cylinder head 3. Secondly, an injector 1, to which screw members 22 and an annular seal member 23 are assembled in advance, is temporally mounted to four mounting holes 16, which is on the sidewall face of the cylinder head 3 and is open to a combustion chamber. Pipe coupling portions 17 of each injector 1 are inserted and fitted into/to fitting holes of an injector mounting portion 143 of the delivery pipe 14. Thirdly, the two arms 142 of the delivery pipe 14 are fixed through an insulator 15 to the mounting portions 143, so that the screw members 22 assembled to the injector 1 are screwed into outer screw portions (n) of the delivery pipe 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mounting structure for an injector used in a direct injection internal combustion engine, particularly for a gasoline direct injection internal combustion engine.

[0002]

2. Description of the Related Art Among fuel (gasoline) injection systems of a gasoline engine, those adopting an in-cylinder injection system can realize lean combustion and reduce fuel consumption as compared with an intake pipe injection system. This is possible and is advantageous in reducing air pollution. In such an in-cylinder injection gasoline engine, the nozzle at the tip of an injector (fuel injection valve) is provided to face the combustion chamber by directly supplying fuel into the cylinder. For this reason, the injector receives in-cylinder pressure at the time of explosion and expansion of the engine at the tip of the nozzle.When mounting this injector, the injector is prevented from falling off from the mounting hole of the injector formed on the engine body side, and at the same time, It is necessary to prevent the combustion gas from leaking. For example, when mounting the injector, an injector press that is tightened to the engine main body with a bolt is used, and the injector press presses and fixes the injector against the engine main body with an axial force stronger than the in-cylinder pressure.

Further, in the injector mounting structure shown in FIG. 6, an injector mounting hole 101 is formed in a cylinder head 100 constituting an engine body, and the diameter of the injector is increased stepwise in accordance with the tip shape of the injector 102 in the mounting hole. Is formed. The enlarged diameter portion 104 of the injector abuts on the injector mounting surface, and a seal member (gasket) 105 is interposed between the enlarged diameter portion and the injector mounting surface 103. Further, a mounting surface 107 of a delivery pipe 106 for fuel supply is formed above the injector mounting surface 103 on the cylinder head 100, and a fixed arm 108 extending from the delivery pipe is bolted to the mounting surface. Fixed at. The injector 102 here has a fitting shaft 109 at its upper end, and this fitting shaft is fitted into the injector mounting portion 110 of the delivery pipe 106 so that fuel can be supplied to the injector 102 via the delivery pipe 106. You. Further, the injector mounting portion 11
0, a cylindrical screw member 111 is screwed, and an annular pressing portion 112 at the tip of the screw member presses an annular step 113 of the injector 102 toward the injector mounting surface 103, whereby the seal member 105 is crushed. The leakage of the combustion gas is prevented by the seal member. For this reason,
The injector is held in metal contact with the cylinder head.

An example of such an apparatus is disclosed in Japanese Patent Application Laid-Open No. 8-
No. 24,692.

[0005]

However, in the conventional injector mounting structure, the injector is in direct metallic contact with the stepped portion of the injector mounting hole, or is tightly pressed against the injector mounting surface 103 via the seal member 105. I have. For this reason, since each of these contact portions easily diffuses and transmits the driving noise of the injector to the engine main body side, when the conventional injector mounting structure is used, there is a problem that the engine noise is increased.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an injector mounting structure capable of blocking transmission of injector driving sound to the engine body and improving the quietness of the engine.

[0007]

According to a first aspect of the present invention, there is provided an engine body provided with a mounting hole that opens to a combustion chamber in the engine body, and the mounting hole has a tip end of an injector. Part is elastically supported via a seal member, a delivery pipe for supplying fuel to the injector is attached to the engine body, and a rear end of the injector is elastically supported by the engine body via the delivery pipe. Features. For this reason, since the front end and the rear end of the injector are elastically supported by the engine main body, it is possible to reduce the area where the two are in close contact with each other due to metal contact or the like, and the driving sound of the injector is transmitted to the engine main body side. Can be prevented and engine noise can be reduced. Further, the pressing force due to the in-cylinder pressure received by the injector at the distal end is received by the engine main body from the delivery pipe, and the injector can be securely mounted and supported on the engine main body, and the seal portion is provided between the distal end of the injector and the mounting hole. Sealability can be reliably maintained.

Preferably, the mounting hole has a straight portion, and the tip of the injector is elastically supported by the straight portion via a seal member. In this case, even if the tip of the injector is displaced in the axial direction, the seal member can reliably and stably maintain the sealing property with the straight portion of the mounting hole.

[0009]

1 and 3 show an injector mounting structure according to an embodiment of the present invention. Here, FIG. 3 is a plan view of an in-cylinder injection type multi-cylinder engine (hereinafter simply referred to as an engine) E equipped with an injector mounting structure as viewed from above, and FIG. 2 is a mounting portion of one injector 1 in the engine E. It is principal part sectional drawing which shows.
As shown in FIG. 2 and FIG. 3, the main body of the engine E is configured by integrating a cylinder head 3 having a head cover 2 bolted to an upper portion thereof, a cylinder block 4 therebelow, and a crankcase and a crank cover (not shown) in this order. Is done.

The cylinder block 4 is provided with four cylinders S in its longitudinal direction. A piston 5 having a concave portion on the top surface is slidably fitted in each cylinder S, and a combustion chamber is mounted on the upper part of each cylinder S. A chamber C is formed. A lower portion of the cylinder block 4 accommodates a crankshaft, a connecting rod, and the like (not shown) for converting the reciprocating motion of the piston 5 into a rotational motion. Since the configuration of each cylinder of the engine E is substantially the same, the same reference numerals are given to the same members in FIG. 3, and the repeated description will be omitted.

The cylinder head 3 has a cylinder-facing lower wall surface 11 formed at a position facing each cylinder S which is sequentially provided in the longitudinal direction. The lower wall 11 has a pair of intake ports 6 on one side (upper side in FIG. 3) of the cylinder head 3 connected to the axis L of each cylinder S on one side (upper side in FIG. 3). A pair of exhaust ports 7 are respectively provided (on the lower side in FIG. 3). Further, an ignition plug 12 is mounted substantially at the center of the lower wall surface 11 facing the cylinder, and an injector 1 for fuel injection is disposed between a pair of intake ports 6 at a peripheral edge of the lower wall surface 11 facing the cylinder. .

A delivery pipe 14 for supplying fuel which is long in the longitudinal direction of the cylinder head 3 is provided on a side wall surface of the cylinder head 3. The delivery pipe 14 includes a pipe-shaped tubular main portion 141 through which fuel flows, and two arm portions 142 extend from the tubular main portion. FIG.
As shown in FIG. 3, the mounting surface 13 of the delivery pipe 14 is formed at two places on the side wall surface of the cylinder head 3, and the two arm portions 142 of the delivery pipe are interposed on both mounting surfaces 13 via the insulator 15. It is tightened and fixed with bolts B. Note that the insulator 15 is formed of a thick elastic resin having a vibration absorbing property, for example, a PP resin or the like, thereby reducing metal contact between the arm portion 142 and the mounting surface 13.

The annular main portion 141 of the delivery pipe 14
Is connected at one end to a high-pressure pipe 24 to which fuel pressurized from the fuel pump P side is supplied, and to the other end is connected to a return pipe 25 for guiding fuel overflowing from the injector 1 to the high-pressure regulating valve V side. . The fuel that has passed through the high-pressure regulating valve V is returned to a fuel tank (not shown).

The tubular main portion 141 of the delivery pipe 14 is integrally formed with four injector mounting portions 143 in addition to the two arm portions 142. Each injector mounting part 14
Reference numeral 3 denotes a cylinder which is disposed opposite to the injector 1 at a position facing the injector 1 and is formed in a substantially cylindrical shape so as to introduce fuel into each injector. This injector mounting portion 143 is
As shown in FIG. 1, a fitting hole h is formed on the inside and an external thread portion n is formed on the outside. Fitting hole h is tubular main part 14
1 communicates with the fuel path r. Next, the delivery pipe 14
1 will be described with reference to FIG. It should be noted that the injectors of the other cylinders have the same mounting structure, and thus the description thereof will not be repeated.

Here, the cylinder-facing lower wall surface 1 of the first cylinder 1
At one end, a mounting hole 16 that opens toward the combustion chamber is formed between the pair of intake ports 6. This mounting hole 16
As shown in FIG. 1, a small-diameter straight portion 161 formed on the combustion chamber C side and an outer opening 162 outside the cylinder head are provided.
And the step 1 connecting the straight portion 161 and the outer opening 162
63, and the injector 1 is fitted therein.
The injector 1 can be brought into contact with a tubular connecting portion 17 as a rear end portion fitted into the fitting hole h of the delivery pipe 14 and a distal end of the injector mounting portion 143 provided on the base end side of the tubular connecting portion 17. A flange-shaped annular projection 18, a small-diameter portion 19 extending below the annular projection 18, an enlarged-diameter portion 20 bulging at the lower end of the small-diameter portion 19, and extending below the enlarged-diameter portion 20. It has a nozzle part 21 as a tip part which is formed and has a nozzle (not shown) at the tip. The nozzle portion 21 includes a needle valve (not shown) for opening and closing the nozzle.
The nozzle is configured to open and close in response to the driving of an electromagnetic solenoid (not shown) within the nozzle.

An annular groove 171 is formed at the tip of the tubular connecting portion 17 fitted into the fitting hole h of the injector mounting portion 143, and a seal ring e made of an elastic material is fitted in the groove 171. This seal ring e is formed so as to seal between the fitting hole h and the tubular connecting portion 17. The injector mounting portion 143 formed with the outer thread portion n on the delivery pipe 14 side and the tubular connecting portion 17 formed with the annular projection 18 on the injector 1 side are screw members 22 serving as fixing members.
Are integrally connected to each other.

Here, the screw member 22 has a substantially short cylindrical shape, and has an inner screw portion m which is screwed to the outer screw portion n formed on the injector mounting portion 143. One end of the inner screw portion m is formed at one end of the inner screw portion m. Is integrally formed with an annular locking portion 221 which extends from this and locks the annular projecting portion 18 formed on the tubular connecting portion 17. When this screw member 22 is screwed into the external thread portion n, the annular projection 18 is pressed against the tip of the injector mounting portion 143 and connected without any relative displacement, whereby the injector 1 and the delivery pipe are connected. The fuel in the tubular main portion 141 is integrally connected, and can be introduced to the nozzle portion 21 side of the injector 1.

The injector 1 integrally connected to the delivery pipe 14 by a screw member 22 is fitted into the mounting hole 16 and is bolted to the cylinder head 3 via the arm 142 of the delivery pipe 14 and the insulator 15 to be securely supported. You. In this support state, the enlarged diameter portion 20 of the injector 1 is loosely fitted concentrically to the outer opening 162, and the nozzle portion 21 is loosely fitted concentrically to the straight portion 161. To maintain a non-contact state. Here, the nozzle portion 21 has an annular outer groove 211 formed at an intermediate position in the longitudinal direction, and the annular outer groove 211 has an annular sealing member 23 as a sealing member.
Are fitted without any deviation. The annular seal member 23 is formed of an elastic body into a ring shape. Here, the annular seal member 23 is formed of an elastic resin having high heat resistance, such as PTFE (fluororesin) or fluororubber.

As described above, the nozzle portion 21 for externally fitting the annular seal member 23 itself keeps a non-contact state with the straight portion 161, and the nozzle portion 2 is formed by the annular seal member 23.
1 and the straight portion 161 are securely sealed. The above-described annular seal member 23 is provided with an annular outer groove 211 of the nozzle portion 21.
Instead of this, as shown in FIG. 4, instead of this, an annular inner groove d is formed in the intermediate portion of the straight portion 161 and the annular seal member 23 'is previously fitted therein, and the The nozzle portion 21 may be configured to be inserted into the annular seal member 23 'above. The annular sealing member 23 'in this case
It is desirable that the elastic member is also an elastic member. For example, a ring-shaped member made of spring steel whose inner diameter can be minutely displaced may be used.

Here, the mounting of the injector 1 in the engine using the injector mounting structure shown in FIGS. 1 to 3 will be described. First, a delivery pipe 14 for supplying fuel, which is long in the longitudinal direction of the cylinder head, is provided on a side wall surface of the cylinder head 3 located at an upper portion on the engine body side.
The two arm portions 142 are fixed to the mounting surfaces 13 of the cylinder head 3 by bolts. Next, the injector 1 on which the screw member 22 and the annular seal member 23 have been assembled is temporarily attached to the four mounting holes 16 on the side wall surface.

In this case, the tubular connecting portion 17 of each injector 1 is connected to the injector mounting portion 14 on the delivery pipe 14 side.
3 is fitted into the fitting hole h. Then, delivery pipe 1
The two arm portions 142 on the fourth side are bolted to the cylinder head 3 via the insulator 15, and then the screw member 22 on the injector 1 side is securely screwed into the external thread portion n on the delivery pipe 14 side, and the injector and the delivery are connected. Connect with the pipe. Thereafter, one end of the delivery pipe 14 fixed to the cylinder head 3 is provided with a fuel pump P
High-pressure pipe 24 communicating with the high-pressure regulating valve V
The return pipe 25 communicating with the side is connected.

As described above, according to the injector mounting structure of FIGS. 1 to 3, the arm portion 142 is supported by the cylinder head 3 and the nozzle portion 21 is supported by the straight portion 161 via the annular seal member 23. Can be kept out of contact with the cylinder head 3 (floating state).
Therefore, transmission of the driving sound of the injector 1 to the cylinder head 3 side can be cut off, and engine noise can be reliably reduced. In particular, here, the arm portion 142 is the insulator 1
The nozzle 1 is bolted to the cylinder head 3 via the through hole, and the nozzle portion 21 is supported by the straight portion via the annular seal member 23, so that the injector 1 and the cylinder head 3 come into metal contact with each other while preventing combustion gas from leaking. The parts can be reduced more reliably, the driving noise of the injector 1 can be more reliably cut off, and the engine noise can be reduced sufficiently.

Further, the pressing force due to the in-cylinder pressure received by the injector 1 is received by the cylinder head 3 from the arm portion 142 via the bolt B, and the injector 1 can be securely mounted on the cylinder head 3 and supported. In addition, even if the nozzle portion 21 is displaced in the axial direction, the annular seal member 23 can reliably maintain the sealing property with the straight portion 161. Further, here, the screw member 22 which is a fixing member is tightened so that the injector mounting portion 143 and the tubular connecting portion 1
7 can easily be integrally connected.

In the injector mounting structure shown in FIG. 1, the screw member 22 serving as a fixing member is incorporated in the injector 1 in advance. Alternatively, the screw member 22 may be configured as shown in FIG. . In this case, the injector mounting portion 1
An annular projection 18a is formed on 43a, and an external thread portion n is formed on the cylindrical connecting portion 17a. An annular locking portion 221 for locking the annular projecting portion 18a is formed, and a screw member 22a as a fixing member screwed to the outer thread portion n is temporarily attached to the injector mounting portion 143a side. The annular projection 18a on the injector mounting part 143a side and the cylindrical connecting part 17a
A seal ring e 'is provided between the abutting portions. Also in this case, by screwing the screw member 22a into the outer screw portion n, the injector mounting portion 143a and the cylindrical connecting portion 17
a can be integrally joined, and the seal ring e 'in which these gaps are crushed can be reliably sealed.

Further, the configuration may be as shown in FIG. In this case, the injector mounting part 143b on the delivery pipe 14 side and the cylindrical connecting part 17 on the injector 1 side
An annular projection 18b, 18b 'is formed at each of the projecting ends of the annular projection 18b, and a seal ring e "is provided between the abutting portions of the annular projections 18b, 18b'. A plurality of bolt holes j are respectively formed in the circumferential direction of the annular projection 18b ', a bolt k serving as a fixing member is inserted into these holes, and the bolts j are tightened to connect the injector mounting portion 143b and the tubular connection. The portion 17b is integrally joined, and the gap between the two is securely sealed by the seal ring e ″. When the screw members 22 used in the injector mounting structure in FIG. 1 are replaced with the modified examples in FIGS. 5A and 5B, substantially the same operation and effect can be obtained.

[0026]

According to the first aspect of the present invention, the rear end of the injector is elastically supported by the engine body via the delivery pipe, and the distal end is elastically supported by the mounting hole through the seal member. Seals the gap between the tip and the mounting hole, and the other parts of the injector are held in non-contact with the engine body. For this reason, since the front end and the rear end of the injector are elastically supported by the engine main body, it is possible to reduce the area where the two are in close contact with each other due to metal contact or the like, and the driving sound of the injector is transmitted to the engine main body side. And reduce engine noise,
Quietness can be improved. Further, the pressing force due to the in-cylinder pressure received by the injector at the distal end is received by the engine main body from the delivery pipe, and the injector can be securely mounted on the engine main body and supported, and the seal member is provided between the distal end of the injector and the mounting hole. Sealability can be reliably maintained.

[Brief description of the drawings]

FIG. 1 is an enlarged cutaway sectional view of an injector mounting portion of an engine to which an injector mounting structure of the present invention is applied.

FIG. 2 shows an injector mounting portion of FIG. 1, and FIG.
FIG. 3 is a sectional view taken along line III-III.

FIG. 3 is a schematic plan view of an engine to which the injector mounting structure of FIG. 1 is applied.

FIG. 4 is a cutaway sectional view of a main part of a modified example of a seal ring used in the injector mounting structure of FIG. 1;

5A and 5B are cutaway sectional views of a fixing member used in the mounting structure of the injector of FIG. 1 and a vicinity thereof, wherein FIG. 5A shows a first modification and FIG. 5B shows a second modification.

FIG. 6 is a sectional view of a conventional injector mounting structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Injector 3 Cylinder head 14 Delivery pipe 141 Tubular main part 142 Arm part 143 Injector mounting part 16 Mounting hole 161 Straight part 17 Tubular connecting part 21 Nozzle part 23 Annular seal member k Bolt C Combustion chamber

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Hirofumi Higashi, Inventor 5-33-8 Shiba, Minato-ku, Tokyo, Mitsubishi Motors Corporation F-term (reference) 3G023 AA11 AA16 AB01 AC04 AD02 AD03 AD12 AE00 AF01 3G024 AA04 BA21 BA29 DA01 DA06 FA00 FA08 GA29 HA14 HA15 3G066 AA02 AA04 AB02 AD12 BA12 BA22 BA28 BA36 CB01 CB05 CB19 CC01 CC03 CC06U CC14 CD04 CD10 CD17 CE22 3G301 HA01 HA04 HA15 JA00 JA37 LB04 LB06 LC01 MA28

Claims (1)

[Claims] An injector has a front end portion elastically supported via a seal member in a mounting hole opened to a combustion chamber in an engine body, and a rear end portion attached to the engine body to supply fuel to the injector. An injector mounting structure, which is elastically supported by the engine body via a pipe.