WO2017094401A1

WO2017094401A1 - Injector, fuel rail, and fuel rail assembly

Info

Publication number: WO2017094401A1
Application number: PCT/JP2016/081657
Authority: WO
Inventors: 相馬　正浩; 洋史大野
Original assignee: 日立オートモティブシステムズ株式会社
Priority date: 2015-11-30
Filing date: 2016-10-26
Publication date: 2017-06-08
Also published as: JP6793661B2; JPWO2017094401A1

Abstract

The present invention reduces manufacturing costs while maintaining sealing performance under high fuel pressure. An injector 10, which is to be attached to an injector attachment part 3 of a fuel rail body 1, is provided with an injector insertion part 5 that is inserted into a pipe insertion part 31 of the injector attachment part 3, and is sealed using a sealing member 7. The injector insertion part 5 is affixed to the housing 14 on the reverse side from the sealing member 7. The injector insertion part 5 is configured such that D2, which is the distance from a sealing position P1, at which the sealing member 7 seals, to a housing affixing position P2, at which the injector insertion part 5 is affixed to the housing, is longer than D1, which is the distance from the inserted end 12 of the injector insertion part 5 to the sealing position P1.

Description

Injector, fuel rail and fuel rail assembly

The present invention relates to an injector, a fuel rail, and a fuel rail assembly.

In-cylinder in-cylinder injection systems that use internal combustion engines, especially gasoline, meet the regulations and requirements for exhaust gas and fuel consumption that are becoming stricter year by year. ) Has become a tendency to further improve the atomization of spray and improve combustion. The fuel pressure is now 15MPa and 20MPa, but higher pressure is expected.

On the other hand, in the conventional fuel rail and injector, the injector is attached via the O-ring in the cup of the fuel rail to which the injector is attached, and the fuel is sealed (for example, see Patent Document 1).

On the other hand, in order to cope with high pressure, in conventional diesel engines, a high-pressure pipe with a seal-shaped tip and nuts to tighten it is provided at both ends, and the rail body seal part is tightened to the injector-side seal part. The metal sealing method is used (see, for example, Patent Document 2).

Japanese Patent Laid-Open No. 2004-360586 JP 2008-163813 A

With the technique disclosed in Patent Document 1, sealing with an O-ring is possible up to a fuel pressure of about 30 MPa. However, when the pressure exceeds 30 MPa, the O-ring protrudes and sealing is not possible. It will be possible.

In the technology as disclosed in Patent Document 2, a high-pressure pipe having a thick portion consisting of a seal portion and a pressing portion at both ends is provided between the fuel rail body and the injector, and clamping members (nuts on both sides) are further provided. ) Are tightened and sealed to the tapered portion on the fuel rail main body side and the tapered portion on the injector side. Therefore, the cost for this high-pressure pipe is required, and further, the taper shape of the seal portion and the screwing for tightening are required for both the rail main body and the injector, which increases the cost.

Also, in order to fix the tip position of the injector at a predetermined position with respect to the combustion chamber of the engine, a separate member for fixing the injector is required in addition to the fixing of the rail body.

An object of the present invention is to provide an injector, a fuel rail, and a fuel rail assembly that can suppress the manufacturing cost while maintaining the sealing performance under a high fuel pressure.

In order to achieve the above object, the present invention provides an injector attached to an attachment portion of a fuel rail, the insertion portion being inserted into an attachment hole of the attachment portion and sealed by a seal member, the insertion portion being the seal The insertion portion is fixed to the housing on the opposite side of the member, and the distance between the end of the insertion portion and the sealing position by the sealing member is longer than the distance from the sealing position to the fixing position with the housing. Configured.

According to the present invention, the manufacturing cost can be suppressed while maintaining the sealing performance under a high fuel pressure. Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

It is sectional drawing which shows the fuel rail assembly by the 1st Embodiment of this invention. It is a figure which shows the state before the assembly of the fuel rail assembly shown in FIG. FIG. 2 is an enlarged view of a seal portion of the fuel rail assembly shown in FIG. 1. It is a figure which shows the state which attached the fuel rail assembly shown in FIG. 1 to the engine head. It is sectional drawing which shows the fuel rail assembly by the 2nd Embodiment of this invention. It is a figure which shows the state before the assembly of the fuel rail assembly shown in FIG. It is a figure which shows an example of a structure of a fuel inlet pipe and a clamping nut. It is a figure which shows another example of a structure of a fuel inlet pipe and a clamping nut. It is a figure which shows the state which attached the fuel rail assembly shown in FIG. 5 to the engine head. It is sectional drawing which shows the fuel rail assembly by the 3rd Embodiment of this invention. It is a figure which shows the state before the assembly of the fuel rail assembly shown in FIG. It is a figure which shows an example of a structure of an injector attachment part and a clamping nut. It is a figure which shows another example of a structure of an injector attachment part and a clamping nut. It is a figure which shows the state which attached the fuel rail assembly shown in FIG. 10 to the engine head.

Hereinafter, the configuration and operation effects of the fuel rail assembly according to the first to third embodiments of the present invention will be described with reference to the drawings. In the following drawings, the dimensions are exaggerated for the purpose of explanation, and are different from the actual scale.

(First embodiment)
First, the overall configuration of the fuel rail assembly according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a fuel rail assembly, and FIG. 2 shows a state before the assembly.

An inlet (not shown) serving as an inlet for supplying high-pressure fuel to a central hole 2 inside the rail from a high-pressure pump (not shown) through a high-pressure pipe (not shown) is attached to the end of the fuel rail body 1 or in the middle thereof. A sensor boss (not shown) to which a pressure sensor (not shown) for measuring the fuel pressure in the center hole 2 is attached is attached to the opposite end of the fuel rail body 1 or in the middle of the fuel rail body 1. These are each formed integrally with the fuel rail body 1 or are formed by being sealed by screwing, brazing, welding or the like and fixed.

The fuel rail body 1 is integrally formed with an injector mounting portion 3 corresponding to the cylinder of the engine. The injector attachment portion 3 has a pipe insertion portion 31, a stopper portion 4, an inner peripheral surface 6, and an attachment screw portion 32 (clamping screw portion). The fuel passage 33 communicates between the pipe insertion portion 31 and the center hole 2. A bracket 11 is integrated with the fuel rail body 1 by welding or the like. A predetermined axial length of the injector 10 is secured between the mounting surface 35 and the stopper portion 4 of the injector mounting portion 3. The bracket 11 has a bolt hole 34 for attaching the rail assembly to the engine.

As shown in FIG. 2, the injector 10 has an injector insertion portion 5 that supplies fuel to the inside of the injector 10. An insertion portion end 12 having a flat portion is formed on the entrance side. The distance from the insertion portion end 12 to the injector tip 24 is a predetermined dimension. Moreover, the injector insertion part 5 is formed substantially straight. Specifically, the injector insertion portion 5 is formed straight up to the position of the housing fixing portion 15 that is integral with the internal components of the injector 10, or is joined by welding or the like in the middle to be straight. The plate thickness t of the injector insertion portion 5 is not more than 1/4 of the outer diameter D of the injector insertion portion 5.

A seal member 7, a pressing member 8, and a tightening member 9 are separately provided on the outer diameter portion of the injector insertion portion 5 of the fuel rail main body 1 and the injector 10. Here, the seal member 7 has a tip seal portion 36 at the tip. As shown in FIG. 3, the pressing member 8 presses the seal member 7 against the gap between the injector insertion portion 5 and the inner peripheral surface 6 on the rail side. As shown in FIG. 2, the tightening member 9 presses the seal member 7 and the pressing member 8 through the mounting screw portion 32. These are prepared for the number of cylinders of the engine including the injector 10.

In a state where the insertion portion end 12 (fuel inlet end) of the injector 10 is abutted against the stopper portion 4 of the injector mounting portion 3 of the fuel rail main body 1, the seal member 7 and the pressing member 8 inserted into the outer periphery of the injector insertion portion 5 The tightening member 9 is tightened with a predetermined torque to apply a pressing load. The tip seal portion 36 of the seal member 7 is inserted into a gap between the outer periphery of the injector insertion portion 5 and the inner peripheral surface 6 of the injector mounting portion 3, pressed, and applied with a predetermined surface pressure.

In other words, as shown in FIG. 1, the inner peripheral side of the pipe insertion portion 31 (mounting hole) of the injector mounting portion 3 (mounting portion) has a stopper portion 4 that determines the axial position of the injector mounting portion 3. The insertion portion end 12 (tip) of the injector insertion portion 5 (insertion portion) is positioned by being abutted against the stopper portion 4.

Since the distance from the stopper portion 4 to the injector tip 24 falls within a preset distance, the dimension of the injector tip 24 from the mounting surface 35 to the stopper portion 4 is matched with the dimension in the injector axial direction from the mounting surface 35 of the bracket 11 to the stopper portion 4. The distance to the position is kept constant, uniform fuel spray can be sent to the combustion chamber 25, combustion is stabilized, and predetermined combustion gas performance is obtained.

When the tightening member 9 is tightened, the seal member 7 is urged in the tightening direction by the pressing member 8 disposed between the tightening member 9 and the seal member 7, and the pressing member 8 includes the seal member 7 and the tightening member. 9 is configured separately.

Thus, the pressing member 8 can be sealed while enhancing the centripetal property of the sealing member 7.

A distance D1 from the insertion portion end 12 of the injector insertion portion 5 of the injector 10 that is sealed and fixed to the fuel rail body 1 by the tightening member 9 to the sealing position that is sealed by the sealing member 7, and from the sealing position to the housing fixing portion 15 The distance D2 is set such that the distance D2 is longer than the distance D1. The distance D2 can also be referred to as the distance from the seal position to the collar portion 5a provided at the portion where the plate thickness is 1/4 or less of the outer diameter of the injector insertion portion 5.

Thus, in this embodiment, as shown in FIG. 1, the injector 10 attached to the injector attachment part 3 (attachment part) of the fuel rail main body 1 (fuel rail) is the pipe insertion part 31 ( The injector insertion portion 5 (insertion portion) is inserted into the attachment hole) and sealed by the seal member 7.

The injector insertion portion 5 is fixed to the housing 14 on the side opposite to the seal member 7. The injector insertion portion 5 is located from the seal position P1 to a housing fixing position P2 that is a fixing position with respect to the housing 14 with respect to a distance D1 from the end (insertion portion end 12) of the injector insertion portion 5 to the seal position P1 by the seal member 7. The distance D2 is configured to be long. Specifically, as shown in FIG. 2, the thickness of the injector insertion portion 5 (insertion portion) is ¼ or less of the diameter of the injector insertion portion 5.

The pipe-shaped part on the injector side is longer than the seal position and satisfies t <(D / 4), so that the pipe on the injector side can be deformed without damaging the seal, and the rail body and bolts on the engine side can be attached. And the misalignment of the injector due to the dimensional variation of the injector insertion portion can be absorbed.

Also, the tip of the injector insertion portion 5 is abutted against the bottom surface of the pipe insertion portion 31 (attachment hole).

As a result, the distance from the stopper portion 4 to the injector tip 24 falls within a preset distance, so that the size of the injector 11 in the axial direction from the mounting surface 35 of the bracket 11 to the stopper portion 4 is matched to the tip of the injector. The distance to position 24 is kept constant, uniform fuel spray can be sent to the combustion chamber 25, combustion is stable, and predetermined combustion gas performance is obtained.

After assembly, the injector insertion portion 5 is located on the inner peripheral side of the inlet side end surface 16 in the entire region closer to the fuel rail body 1 (fuel rail) than the inlet side end surface 16 of the pipe insertion portion 31. That is, the inlet side end face 16 has an annular shape, but the injector insertion portion 5 is located inside thereof.

Thereby, the injector insertion portion 5 can be inserted into the injector mounting portion 3, and the seal and the insertion end can be positioned.

The injector insertion part 5 (insertion part) is a metal pipe formed in a cylindrical shape. By making the injector insertion part 5 into a pipe shape, the misalignment at the time of attachment is easily absorbed.

As shown in FIG. 4, the fuel rail assembly is fixed to the engine with a bolt 21 via a bracket 11 fixed to the fuel rail body 1 by welding or the like. The distance from the mounting surface 35 of the bracket 11 to the stopper portion 4 of the injector mounting portion 3 and the distance from the insertion portion end 12 of the injector 10 to the injector tip 24 have predetermined dimensions. The fuel rail assembly is attached to the engine head with dimensions set in this way.

In other words, in the fuel rail assembly including the injector 10 and the fuel rail body 1 (fuel rail), the mounting surface 35 (end surface) of the bracket 11 attached to the fuel rail body 1 is fixed to the engine head mounting end surface. The tip position of 10 is fixed to a predetermined position with respect to the combustion chamber 25 of the internal combustion engine.

Thus, the fuel rail assembly can be attached to the engine head, the distance of the injector tip position is kept constant, and uniform fuel spray can be sent to the combustion chamber 25. As a result, combustion is stabilized and predetermined combustion gas performance is obtained.

The fuel supplied from the high-pressure pump and the high-pressure pipe is supplied into the center hole 2 of the fuel rail main body 1 through the inlet while maintaining a high-pressure fuel pressure, and passes through the fuel passage 33 and the injector insertion portion 5 to the injector. 10 and supplied to the engine in accordance with the opening of the injector 10.

In the first embodiment, as shown in FIGS. 1 and 2, the fuel rail body 1, the injector 10, the seal member 7, the pressing member 8, and the tightening member 9 are formed separately, and the injector mounting of the fuel rail body 1 is performed. The injector insertion portion 5 is inserted into the pipe insertion portion 31 of the portion 3, and the insertion portion end 12 is attached while being pressed against the stopper portion 4 of the injector attachment portion 3. At this time, the seal member 7 and the tip seal portion 36 of the seal member 7 are tightened with the tightening member 9 so as to press the seal member 7 against the gap between the injector insertion portion 5 and the inner peripheral surface 6 with a predetermined surface pressure. Is possible.

That is, as shown in FIG. 3, when the tightening member 9 is tightened, it is biased in the tightening direction, and the outer peripheral surface of the injector insertion portion 5 (insertion portion) and the inner peripheral surface of the pipe insertion portion 31 (mounting hole). The outer peripheral surface of the injector insertion portion 5 and the inner peripheral surface 6 of the pipe insertion portion 31 are sealed by a seal member 7 that is inserted into a gap formed between the two and the seal member 7.

Thereby, the gap between the injector insertion portion 5 and the inner peripheral surface 6 of the injector mounting portion 3 is sealed by the seal member 7.

Specifically, the inner peripheral surface and the outer peripheral surface of the seal member 7 are formed so as to incline toward the inner peripheral side toward the tightening direction, and when the tightening member 9 is tightened, it is biased in the tightening direction. The tip seal portion 36 (tip portion) of the seal member 7 is inserted into a gap formed between the outer peripheral surface of the injector insertion portion 5 (insertion portion) and the inner peripheral surface 6 of the pipe insertion portion 31 (attachment hole). Fill the gap.

In other words, the inner circumferential surface and the outer circumferential surface of the seal member 7 are formed so as to be inclined toward the inner circumferential side in the tightening direction, and the pipe insertion portion 31 (mounting hole) of the injector mounting portion 3 (mounting portion). The inner peripheral surface 6 is formed so as to be inclined toward the inner peripheral side in the tightening direction. When the tightening member 9 is tightened, the outer peripheral surface of the seal member 7 is configured to come into contact with the inner peripheral surface 6 of the pipe insertion portion 31 by being biased in the tightening direction.

Since the inner peripheral surface 6 is tapered, the seal member 7 can easily fill the gap, and sealing becomes easy.

Fuel passes through the center hole 2 and the fuel passage 33 and flows into the injector insertion portion 5 of the injector 10. Since the tip seal portion 36 of the seal member 7 is pressed at a predetermined surface pressure, a passage that leaks outside through the gap between the outer periphery and the inner peripheral surface 6 of the injector insertion portion 5 is not formed, and fuel leaks to the outside. Can be prevented. Here, the pressing member 8 is used to uniformly transmit the non-uniform load due to the screw of the tightening member 9 to the seal member 7. Even when only the seal member 7 is used without using the pressing member 8, sealing is possible if the overall surface pressure is increased.

The injector 10 presses and fixes the seal member 7 in a state where the insertion portion end 12 of the injector insertion portion 5 is pressed against the stopper portion 4 of the injector mounting portion 3. Therefore, the injector surface 24 from the mounting surface 35 to the injector tip 24 is set according to the dimensions in the injector axial direction from the mounting surface 35 of the bracket 11 to the stopper portion 4 and the dimensions from the insertion portion end 12 to the injector tip 24 of the injector 10. The distance to the position of is kept constant.

As described above, according to this embodiment, the manufacturing cost can be suppressed while maintaining the sealing performance under a high fuel pressure.

Further, according to the present embodiment, the injector insertion portion 5 of the injector 10, the seal member 7 that is separate from the injector insertion portion 5, the pressing member 8, and the clamping member 9 are used, so that the fuel seal and the injector tip 24 Positioning can be performed, and an inexpensive rail assembly can be realized with a simple structure.

(Second Embodiment)
Next, the overall configuration of the fuel rail assembly according to the second embodiment of the present invention will be described with reference to FIGS.

FIG. 5 shows the fuel rail assembly, and FIG. 6 shows the state before the assembly. 7 and 8 show the configuration of the fuel inlet pipe 210 and the tightening nut 207 and the state of integration. FIG. 9 shows a state where the rail assembly is attached to the engine.

An inlet (not shown) serving as an inlet for supplying high-pressure fuel to a central hole 202 inside the rail from a high-pressure pump (not shown) through a high-pressure pipe (not shown) is attached to the end of the fuel rail body 201 or in the middle thereof. A sensor boss (not shown) to which a pressure sensor (not shown) for measuring the fuel pressure in the center hole 202 is attached is attached to the opposite end of the fuel rail body 1 or in the middle of the fuel rail body 201. These are formed integrally with the fuel rail main body 201, or are formed and sealed by screwing, brazing, welding, or the like.

In the fuel rail main body 201, an injector mounting portion 203 corresponding to the cylinder of the engine is formed integrally with the fuel rail main body 201. The injector attachment portion 203 has a seal taper surface 206 and an attachment screw 204. The fuel passage 205 communicates between the seal taper surface 206 and the center hole 202. A bracket 235 is integrated with the fuel rail body 201 by welding or the like. A predetermined length in the axial direction of the injector 213 is secured between the mounting surface 215 and the seal taper surface 206 of the injector mounting portion 203. The bracket 235 has a bolt hole 214 for attaching the rail assembly to the engine.

As shown in FIG. 6, the injector 213 has a fuel inlet pipe 210 that supplies fuel into the injector 213. On the inlet side, the seal taper surface 206 and fuel pipe seat surfaces 209 and 224 constituting the seat portion are formed. The distance from the end (upper end) of the fuel inlet pipe 210 to the injector tip 225 is a predetermined dimension. The fuel inlet pipe 210 includes a tightening nut 207 assembled on the injector 213 side, pipe shoulders 212 and 223 pressed by the tightening nut 207, and fuel pipe seat surfaces 209 and 224 pressed against the seal taper surface 206. have.

The clamping nut 207 is joined together with the fuel inlet pipe 210 to the injector 213 before being assembled to the fuel rail body 201 by welding or the like (see FIG. 7), or the clamping nut 207 is connected to the fuel inlet pipe 210 of the injector. Then, the fuel pipe seat surface 224 and the pipe shoulder 223 are formed (see FIG. 8). These are prepared for the number of engine cylinders including the injector 213.

In a state where the fuel pipe seat surface 209 of the injector 213 is pressed against the seal taper surface 206 of the injector mounting portion 203 of the fuel rail body 201, a tightening nut 207 provided on the outer periphery of the fuel inlet pipe 210 is tightened with a predetermined torque. Thereby, a predetermined surface pressure is applied and sealed.

Thus, the injector 213 is fixed to the injector mounting portion 203 by directly tightening the tightening nut 207 (tightening member) with respect to the injector mounting portion 203 (mounting portion).

Thereby, the injector 213 is fixed to the fuel rail body 201 only by the tightening nut 207 (tightening member).

As shown in FIG. 9, the fuel rail assembly is fixed to the engine with a bolt 226 or the like via a bracket 235 fixed to the fuel rail main body 201 by welding or the like. The distance from the mounting surface 215 of the bracket 235 to the seal taper surface 206 of the injector mounting portion 203 and the distance from the end (upper end) of the fuel pipe seat surface 209 of the injector 213 to the injector front end 225 have predetermined dimensions. The fuel rail assembly is attached to the engine head with dimensions set in this way.

The fuel supplied from the high-pressure pump and the high-pressure pipe is supplied into the center hole 202 of the fuel rail body 201 through the inlet while maintaining a high-pressure fuel pressure, and passes through the fuel passage 205 and the fuel inlet pipe 210 to the injector. 213 is supplied to the engine 213 and supplied to the engine when the injector 213 is opened.

In the second embodiment, as shown in FIGS. 5 and 6, a tightening nut 207 is assembled to the injector 213 and configured separately from the fuel rail body 201. The fuel inlet pipe 210 has a pipe shoulder 212 and a fuel pipe seat surface 209 on the inlet side. The enlarged diameter portion formed by the pipe shoulder 212 and the fuel pipe seat surface 209 is accommodated in the tightening nut 207. When the tightening nut 207 is tightened to the mounting screw 204 of the injector mounting portion 203 of the fuel rail body 201, the tightening shoulder portion 211 presses the pipe shoulder portion 212 and the fuel pipe seat surface 209 is pressed against the seal taper surface 206.

When the tightening nut 207 is tightened with a predetermined torque, a predetermined surface pressure is secured between the seal taper surface 206 and the fuel pipe seat surface 209, and the fuel can be sealed. The fuel passes through the center hole 202 and the fuel passage 205 and flows into the fuel inlet pipe 210 of the injector 213. However, fuel leaks to the outside at a predetermined surface pressure between the seal taper surface 206 and the fuel pipe seat surface 209. Can be prevented.

The injector 213 is integrated with the fuel inlet pipe 210. In order to press and fix the fuel pipe seat surface 209 to the seal taper surface 206 of the injector mounting portion 203, the dimension in the injector axial direction from the mounting surface 215 of the bracket 235 to the seal taper surface 206, and the injector 213 Depending on the dimension from the end (upper end) of the fuel pipe seat surface 209 to the injector tip 225, the distance from the mounting surface 215 to the position of the injector tip 225 is kept constant.

The fuel inlet pipe 210 is formed with an enlarged diameter portion by the pipe shoulder 212 and the fuel pipe seat surface 209, so that the injector 213 is assembled after the clamping nut 207 and the fuel inlet pipe 210 are assembled as shown in FIG. It is fixed to the side by welding or the like as indicated by a welded portion 221.

Alternatively, as shown in FIG. 8, the fuel inlet pipe 210 on the injector side is made in a straight shape, and the pipe shoulder 223 and the fuel pipe seat surface 224 are molded by plastic working after the fastening nut 207 is assembled. Can be produced.

According to the present embodiment, the injector 213 can be sealed and fixed to the fuel rail body 201 with only the tightening nut 207, the injector tip 225 can be positioned with respect to the mounting surface 215, and set at a predetermined position with respect to the combustion chamber 228. Therefore, an inexpensive rail assembly can be realized with a simple structure.

(Third embodiment)
Next, the overall configuration of the fuel rail assembly according to the third embodiment of the present invention will be described with reference to FIGS. In this embodiment, compared with the second embodiment, the attachment of the seal taper surface and the tightening nut is reversed.

FIG. 10 shows the fuel rail assembly, and FIG. 11 shows the state before the assembly. 12 and 13 show the configuration of the injector mounting portion 103 and the tightening nut 107 and the state of integration. FIG. 14 shows a state where the rail assembly is attached to the engine.

An inlet (not shown) serving as an inlet for supplying high-pressure fuel to a central hole 102 inside the rail from a high-pressure pump (not shown) through a high-pressure pipe (not shown) is attached to the end or in the middle of the fuel rail body 101. A sensor boss (not shown) to which a pressure sensor (not shown) for measuring the fuel pressure in the center hole 102 is attached is attached to the opposite end of the fuel rail body 101 or in the middle of the fuel rail body 101. These are formed integrally with the fuel rail main body 101, or are formed by being sealed by screwing, brazing, welding, or the like, and fixed.

The fuel rail main body 101 is integrally formed with an injector mounting portion 103 corresponding to the cylinder of the engine. Attachment sheet surfaces 119 and 131 are formed on the injector attachment portion 103. The distance from the mounting surface 115 of the bracket to the tip of the injector mounting portion 103 is a predetermined dimension. The injector mounting portion 103 includes a tightening nut 107 tightened to the injector 113 side, mounting

shoulder portions

112 and 130 pressed by the tightening nut 107, and mounting

seat surfaces

119 and 131 pressed against the seal taper surface 109 on the injector side. have.

The clamping nut 107 is joined to the fuel rail body 101 side together with the injector mounting portion 103 before the rail assembly by welding or the like (see FIG. 12), or the clamping nut 107 is joined to the injector mounting portion of the fuel rail body 101. After mounting in 103, the mounting sheet surface 131 and the mounting shoulder 130 are formed (see FIG. 13). These are prepared for the number of engine cylinders including the injector 113.

The fuel passage 105 communicates between the attachment seat surface 119 and the center hole 102. A bracket 135 is integrated with the fuel rail body 101 by welding or the like. A predetermined axial length of the injector 113 is ensured between the mounting surface 115 and the mounting sheet surface 119 of the injector mounting portion 103. The bracket 135 has a bolt hole 136 for attaching the rail assembly to the engine.

The injector 113 has a fuel inlet pipe 110 that supplies fuel to the inside of the injector 113. On the inlet side, the mounting seat surface 119 and the seal taper surface 109 constituting the seat portion are formed. The distance from the end (upper end) of the fuel inlet pipe 110 to the injector front end 125 is a predetermined dimension. The fuel inlet pipe 110 is provided with a tightening screw 137 into which the tightening nut 107 is tightened.

In a state where the seal taper surface 109 of the injector 113 is pressed against the mounting sheet surface 119 of the injector mounting portion 103 of the fuel rail body 101, the tightening nut 107 provided on the outer periphery of the injector mounting portion 103 is tightened with a predetermined torque. Thereby, a predetermined surface pressure is applied and sealed.

As shown in FIG. 14, the fuel rail assembly is fixed to the engine with a bolt 126 or the like via a bracket 135 fixed to the fuel rail body 101 by welding or the like. The distance from the mounting surface 115 of the bracket 135 to the end (lower end) of the mounting sheet surface 119 of the injector mounting portion 103 and the distance from the end (upper end) of the seal taper surface 109 of the injector 113 to the injector tip 125 are respectively predetermined. It becomes a dimension. The fuel rail assembly is attached to the engine head with dimensions set in this way.

The fuel supplied from the high-pressure pump and the high-pressure pipe is supplied into the center hole 102 of the fuel rail body 101 through the inlet while maintaining a high-pressure fuel pressure, and passes through the fuel passage 105 and the fuel inlet pipe 110 to the injector. 113 is supplied into the engine 113 and supplied to the engine in accordance with the opening of the injector 113.

In the third embodiment, the seal taper surface 109 and the tightening screw 137 are provided on the injector 113 side, and the tightening nut 107 and the mounting shoulder 112 are provided on the fuel rail body 1 side. The same effect can be obtained.

A tightening nut 107 is assembled on the fuel rail body 101 side, and is configured separately from the injector 113. The injector mounting portion 103 has a mounting shoulder 112 and a mounting seat surface 119 on the distal end side. The enlarged diameter portion formed by the attachment shoulder 112 and the attachment seat surface 119 is accommodated in the tightening nut 107. When the tightening nut 107 is tightened to the tightening screw 137 of the fuel inlet pipe 110, the tightening shoulder 111 presses the mounting shoulder 112 and the mounting seat surface 119 is pressed against the seal taper surface 109.

When the tightening nut 107 is tightened with a predetermined torque, a predetermined surface pressure is secured between the seal taper surface 109 and the mounting seat surface 119, and fuel can be sealed. The fuel passes through the central hole 102 and the fuel passage 105 and flows into the fuel inlet pipe 110 of the injector 113. However, the fuel leaks to the outside with a predetermined surface pressure between the seal taper surface 109 and the mounting seat surface 119. Can be prevented.

The fuel rail body 101 is integrated with an injector mounting portion 103. In order to press and fix the mounting sheet surface 119 against the seal taper surface 109 of the injector, the dimensions in the injector axial direction from the mounting surface 115 of the bracket 135 to the end (lower end) of the mounting sheet surface 119 and the injector 113 are set in advance. The distance from the mounting surface 115 to the position of the injector tip 125 is kept constant by the dimension from the end (upper end) of the seal taper surface 109 to the injector tip 125.

The injector mounting portion 103 is formed with an enlarged diameter portion by the mounting shoulder portion 112 and the mounting seat surface 119. Therefore, as shown in FIG. 12, the fuel rail main body is assembled after the fastening nut 107 and the injector mounting portion 103 are assembled. Fix to the 101 side by welding or the like.

Alternatively, as shown in FIG. 13, the injector mounting portion 103 can be made in a straight shape, and the mounting shoulder portion 130 and the mounting sheet surface 131 can be formed by plastic working after the fastening nut 107 is assembled.

According to this embodiment, the injector 113 can be sealed and fixed to the fuel rail body 101 only with the tightening nut 107, the injector tip 125 can be positioned with respect to the mounting surface 115, and set to a predetermined position with respect to the combustion chamber 128. Therefore, an inexpensive rail assembly can be realized with a simple structure.

Note that the present invention is not limited to the above-described embodiment, and includes various modifications. For example, the above-described embodiment has been described in detail for easy understanding of the present invention, and is not necessarily limited to the one having all the configurations described. Further, a part of the configuration of an embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of an embodiment. In addition, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

DESCRIPTION OF SYMBOLS 1 ... Fuel rail main body 2 ... Center hole 3 ... Injector attachment part 4 ... Stopper part 5 ... Injector insertion part 6 ... Inner peripheral surface 7 ... Seal member 8 ... Pushing member 9 ... Fastening member 10 ... Injector 11 ... Bracket 12 ... Insertion Part end 14 ... Housing 15 ... Housing fixing part 16 ... Inlet end face 21 ... Bolt 22 ... Head mounting end face 23 ... Engine head 24 ... Injector tip 25 ... Combustion chamber 31 ... Pipe insertion part 32 ... Mounting screw part 33 ... Fuel passage 34 ... Bolt hole 35 ... Mounting surface 36 ... End seal portion 201 ... Fuel rail body 202 ... Center hole 203 ... Injector attachment portion 204 ... Mounting screw 205 ... Fuel passage 206 ... Seal taper surface 207 ... Clamping nut 208 ... Clamping portion screw 209 ... Fuel pipe seat surface 210 ... Fuel inlet pipe 211 ... Fastening shoulder 212 ... Pipe shoulder 213 ... Injector 214 ... Bolt hole 215 ... Mounting surface 221 ... Welded portion 223 ... Pipe shoulder 224 ... Fuel pipe seat surface 225 ... Injector tip 226 ... Bolt 227 ... Engine head 228 ... Combustion chamber 234 ... Bolt hole 235 ... Bracket 101 ... Fuel rail Main body 102 ... Center hole 103 ... Injector mounting portion 105 ... Fuel passage 107 ... Clamping nut 109 ... Seal taper surface 110 ... Fuel inlet pipe 111 ... Clamping shoulder portion 112 ... Mounting shoulder portion 113 ... Injector 115 ... Mounting surface 119 ... Mounting Seat surface 125 ... Injector tip 126 ... Bolt 127 ... Engine head 128 ... Combustion chamber 135 ... Bracket 136 ... Bolt hole

Claims

In the injector attached to the mounting part of the fuel rail,
The insertion portion is inserted into the attachment hole of the attachment portion, and includes an insertion portion that is sealed by a seal member,
The insertion portion is fixed to the housing on the opposite side of the seal member;
The injector is configured such that a distance from the sealing position to a fixing position with the housing is longer than a distance from an end of the insertion part to a sealing position by the sealing member. .
In the injector attached to the mounting part of the fuel rail,
The insertion portion is inserted into the attachment hole of the attachment portion, and includes an insertion portion that is sealed by a seal member,
The injector is characterized in that the thickness of the insertion portion is configured to be ¼ or less of the diameter of the insertion portion.
The injector according to claim 1 or 2,
The injector is characterized in that the distal end of the insertion portion is configured to abut against the bottom surface of the mounting hole.
The injector according to claim 1 or 2,
The injector is characterized in that the insertion portion is configured to be located on an inner peripheral side of the inlet side end surface in an entire region on the fuel rail side from an inlet side end surface of the mounting hole.
The injector according to claim 1 or 2,
The injector is fixed to the attachment portion by directly fastening a fastening member to the attachment portion.
The injector according to claim 1 or 2,
By a sealing member that is urged in the tightening direction when the tightening member is tightened and is inserted into a gap formed between the outer peripheral surface of the insertion portion and the inner peripheral surface of the mounting hole. The injector, wherein an outer peripheral surface of the insertion portion and an inner peripheral surface of the mounting hole are sealed.
The injector according to claim 1 or 2,
The injector is characterized in that the insertion portion is a metal pipe formed in a cylindrical shape.
The injector according to claim 1 or 2,
The inner peripheral surface and the outer peripheral surface of the seal member are formed so as to be inclined toward the inner peripheral side in the tightening direction, and when the tightening member is tightened, the front end of the seal member is biased in the tightening direction. The injector is inserted into a gap formed between the outer peripheral surface of the insertion portion and the inner peripheral surface of the mounting hole, and fills the gap.
The injector according to claim 1 or 2,
An inner peripheral surface and an outer peripheral surface of the seal member are formed so as to be inclined toward the inner peripheral side in the tightening direction, and an inner peripheral surface of the mounting hole of the mounting portion is an inner peripheral side in the tightening direction. Formed to incline,
An injector, wherein the outer peripheral surface of the seal member is configured to come into contact with the inner peripheral surface of the mounting hole by being biased in the tightening direction when the tightening member is tightened.
The injector according to claim 1, wherein
An inner peripheral side of the mounting portion of the mounting portion has a stopper portion that determines an axial position of the insertion portion, and the distal end of the insertion portion is positioned by being abutted against the stopper portion. To injector.
The injector according to claim 1, wherein
The seal member is urged in the tightening direction by a pressing member disposed between the tightening member and the seal member when the tightening member is tightened,
The injector, wherein the pressing member is configured separately from the sealing member and the clamping member.
In a fuel rail having a mounting portion to which an injector is mounted,
The injector includes an insertion portion sealed by a seal member;
A fuel rail, characterized in that the tip of the insertion portion is abutted against the bottom surface of the attachment hole of the attachment portion.
The fuel rail of claim 12,
The fuel rail, wherein the insertion portion is configured to be located on an inner peripheral side with respect to the inlet side end surface in an entire region on the fuel rail side with respect to the inlet side end surface of the mounting hole.
The fuel rail of claim 12,
The fuel rail, wherein the injector is fixed to the attachment portion by directly fastening a fastening member to the attachment portion.
The fuel rail of claim 14,
A sealing member that is urged in the tightening direction when the tightening member is tightened and is inserted into a gap formed between the outer peripheral surface of the insertion portion and the inner peripheral surface of the mounting hole, and seals the gap. The fuel rail, wherein the outer peripheral surface of the insertion portion and the inner peripheral surface of the mounting hole are sealed.
The fuel rail of claim 12,
An inner peripheral side of the mounting portion of the mounting portion has a stopper portion that determines an axial position of the insertion portion, and the distal end of the insertion portion is positioned by being abutted against the stopper portion. Fuel rails.
A fuel rail assembly comprising the injector according to any one of claims 1 to 11 and the fuel rail.
The fuel rail assembly of claim 17, wherein
A fuel rail assembly, wherein an end face of a bracket attached to the fuel rail is fixed to an engine head attaching end face, and a tip position of the injector is fixed to a predetermined position with respect to a combustion chamber of an internal combustion engine.