JP2002227726A - Fuel supply device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent vaporization of fuel inside an injector and icing occurring by heart removal by injected fuel. SOLUTION: This fuel supply device holds the injector 11 in a mounting hole 61 formed on a cylinder head 6 and injects/supplies fuel from an injection port 201 opened on a tip face of the injector 11. A fuel guide passage 401 for guiding the fuel from the injection port 201 is provided and a thermal conductivity member 4 surrounding the fuel guide passage 401 and abutting on the cylinder head 6 is arranged thereon. Thereby the vicinity of an outlet 4011 of the fuel guide passage 401 is not overcooled by the fuel and receives heat from the cylinder head 6 by holding the injector 11 in the mounting hole 61 via a heat insulating holding member 3 for preventing the fuel inside the injector 11 from vaporizing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fuel supply device for an internal combustion engine.

[0002]

2. Description of the Related Art Some internal combustion engines use a liquefied fuel gas such as LPG as a fuel in a liquid phase. Such a fuel supply device for an internal combustion engine liquefies a liquefied fuel gas under a certain low temperature under a pressurized state, stores it in a fuel tank, and supplies it to an injector in a liquid phase.

[0003] The injector is mounted inside a cylinder head, an intake pipe wall, or the like by forming a mounting hole in a partition wall through which intake air flows, and fuel is injected and supplied into the partition wall opening at the front end face of the injector. The fuel is vaporized during injection and takes a large amount of latent heat of vaporization. As a result, water in the intake air freezes near the injection hole of the injector (icing) and adheres around the injection hole, forming ice blocks that block the injection hole. May grow. As a result, the substantial opening area of the injection hole is reduced, and the fuel flow rate changes. Eventually, after growing into an ice block, the ice block suddenly detaches, and by repeating this, there arises a problem that the fuel injection amount increases and decreases and the air-fuel ratio fluctuates.

Japanese Unexamined Patent Publication No. 9-264228 discloses a fuel supply system comprising a supply pipe for supplying fuel from a fuel tank to an injector and a return pipe for collecting surplus fuel from the injector to the fuel tank in order to prevent icing. A heater or a heating unit using the heat of the cooling water of the internal combustion engine is provided in the middle of the circulation path to heat the fuel to prevent icing (first conventional example).

Japanese Patent Application Laid-Open No. 2000-234578 discloses an apparatus in which an anti-icing member that rises in a mortar shape is provided at an injector mounting port of an intake manifold in front of an injection hole of an injector. In this technology, in order to avoid icing due to dew condensation on the injection hole of the injector after the engine is stopped when the outside air is below freezing, a mortar-shaped icing prevention member is formed before the low-temperature intake air reaches the injection hole. Dew condensation occurs on the surface (second conventional example).

[0006]

However, in the first conventional example, when applied to an internal combustion engine using a liquefied fuel gas, when the fuel is heated, the fuel is easily vaporized,
There is a problem that the adjustment accuracy of the injection amount is reduced.

In the second prior art, since the moisture in the intake air must be sufficiently condensed, the anti-icing member is opened in a mortar shape so that the heat transfer area is made as large as possible, and liquefied fuel gas is used. When the present invention is applied to an internal combustion engine, heat around the injection hole is gradually removed by heat transfer to the injected fuel from the anti-icing member arranged so as to surround the injection hole. For this reason, icing is more likely to occur.

[0008] The present invention has been made in view of the above circumstances,
It is an object of the present invention to provide a fuel supply system for an internal combustion engine that can prevent icing without causing vaporization.

[0009]

According to the first aspect of the present invention, a mounting hole for an injector is formed in a partition wall through which intake air flows inside, the injector is held in the mounting hole, and an injection hole opening at a tip end surface of the injector. A fuel supply device for an internal combustion engine that supplies fuel forming an air-fuel mixture with the intake air from the inside of the partition wall, wherein an injector is held in the mounting hole via a holding member made of a heat insulating material, and the injection hole of the injector is provided. A fuel guide passage for guiding the fuel injected from the fuel tank to the inside of the partition; a through-hole reaching the inside of the partition is formed at the fuel passage formation position; A heat conductive member that is in contact with a portion or a partition, and reduces the area of the wall surface of the fuel guide channel from a part of the partition or the heat conductive member from the wall of the fuel guide channel. It is set smaller than the heat transfer area of the sites that define the heat transfer.

The fuel injected from the injection hole of the injector is different from the second conventional example in which the anti-icing member is open toward the intake passage. Since the area of the flow path wall of the flow path is limited, vaporization is suppressed and the fuel flows through the fuel guide flow path in a gas-liquid mixed state. Then, when reaching the outlet of the fuel guide flow path, the heat receiving area increases, so that it evaporates rapidly. The fuel guide channel is surrounded by a part of the partition or a heat conductive member that is in contact with the partition, and heat is transferred from the part of the partition or the partition on the outer periphery of the heat conductive member through these. Here, the area of the fuel guide channel wall surface where heat is absorbed by the fuel is limited to be smaller than the heat transfer area of a part of the partition wall or a portion that regulates heat transfer from the heat conductive member to the fuel guide channel wall surface. Therefore, in the vicinity of the fuel guide flow path, the heat supply from the partition wall tends to be more than the heat loss by the fuel, and in the vicinity of the outlet of the fuel guide flow path, the heat is supplied from the partition wall to decrease the temperature. Thus, icing can be prevented.

Further, since the injector is held in the mounting hole via a holding member made of a heat insulating material, it is possible to suppress the heat transfer from the partition wall and prevent the fuel in the injector from being vaporized. be able to.

According to a second aspect of the present invention, in the configuration of the first aspect, a low heat conductive portion is provided on an outer periphery of the fuel guide passage near the fuel guide passage.

By providing a portion having low thermal conductivity close to the fuel guide flow path, heat transfer is suppressed, so that heat loss due to flowing fuel is suppressed, and icing can be further prevented. In addition, by suppressing the heat loss, excessive heat supply from the partition to the vicinity of the fuel guide flow path becomes unnecessary, and it is possible to further suppress the fuel in the injector from being vaporized.

According to a third aspect of the present invention, in the configuration of the second aspect of the present invention, a through hole is formed in a part of the partition or the heat conductive member, and the flow of the fuel guide flow path is formed in the through hole. A cylindrical member constituting the innermost peripheral portion of the road wall is inserted to form the low thermal conductivity portion.

At the innermost periphery of the flow path wall of the fuel guide flow path closest to the fuel, the heat transfer is suppressed, so that the heat loss due to the flowing fuel is suppressed.

According to a fourth aspect of the present invention, in the configuration of the second aspect of the present invention, an annular gap is formed on an outer periphery of an innermost peripheral portion of a flow path wall of the fuel guide flow path, and the low thermal conductivity portion is formed. I do.

Since the annular gap serves as a heat transfer barrier, the heat removal site by the circulating fuel is substantially restricted to the innermost portion of the flow path wall of the fuel guide passage closest to the fuel. The heat capacity of the part is relatively small. As a result, heat removal by the circulating fuel is suppressed.

According to a fifth aspect of the present invention, in the configuration of the first or second aspect of the present invention, a tip end face of the injector in which the injection hole is opened, and a bottom surface of the mounting hole in which the through hole is opened or the thermal conductive material is provided. An O-ring is provided between the rear end surfaces of the members so that the fuel flowing from the injection holes to the fuel guide flow path
Avoid spillage on the outer circumference of the ring.

Since the outer circumference of the O-ring does not become a dead volume, the heat receiving area of the fuel flowing from the injection hole to the fuel guide passage is reduced, and the heat loss by the fuel is suppressed.
Icing can be prevented more favorably.

According to a sixth aspect of the present invention, in the configuration of the first aspect of the invention, the partition has a structure through which the mounting hole penetrates, and the mounting hole is closed by the heat conductive member at a tip end side of the injector. A flow path member integrally formed with the tip end of the injector and having a tubular portion having the inside as the fuel guide flow path protruding at a position facing the injection hole, wherein the heat conductive member and the flow path member are provided; To form a gap.

Since the flow path member is integrated with the injector, regardless of the state of attachment of the injector to the partition,
The relative position between the injection hole and the fuel guide channel does not change. As a result, it is possible to prevent the ejection characteristics from changing over time and from variation between apparatuses.

According to a seventh aspect of the present invention, in the configuration of the first to sixth aspects, a groove-shaped portion is formed on a part of the partition wall or the surface of the heat conductive member where the outlet of the fuel guide passage opens. A recess is formed.

It is possible to prevent water in the form of liquid droplets condensed during the stoppage of the internal combustion engine from entering from the outlet of the fuel guide passage, and at low temperatures, the fuel guide passage is blocked by ice to deteriorate startability. Can be prevented.

According to an eighth aspect of the present invention, in the configuration of the first to seventh aspects, a part of the partition or the heat conductive member is projected inside the partition.

Since the flow speed of the intake air increases as the distance from the partition increases, the fuel injected from the outlet of the fuel guide passage quickly flows downstream of the intake air. This prevents the fuel from staying in the vicinity of the outlet of the fuel guide passage, and further suppresses the vicinity of the outlet from being heated by the fuel injected from the outlet of the fuel guide passage.

[0026]

(First Embodiment) FIG. 2 shows the overall structure of a fuel supply device for an internal combustion engine according to the present invention. The fuel supply device is a four-cylinder internal combustion engine, and has a one-to-one fuel injector for fuel injection provided in each cylinder using LPG as a liquid liquefied fuel gas stored in an LPG tank 12 as fuel. LPG is delivered to each injector 11 from a delivery pipe 131 located at the downstream end of the delivery pipe 13. The delivery pipe 131 is connected to a collection pipe 14 for collecting excess LPG into the LPG tank 12.

The delivery pipe 13 is provided with a fuel pump 15 for delivering LPG to the delivery pipe 131. Further, a relief valve 16 is provided in the recovery pipe 14, and the fuel pressure in the delivery pipe 131 is regulated by the relief pressure.

FIG. 1 shows an attached state of an injector 11. The injector 11 is attached to a cylinder head 6 which is a partition of each cylinder together with a fuel guide 4 described later, and an intake passage formed using the cylinder head 6 as a partition. Inject fuel inside. Each cylinder has a common configuration shown in the figure, and fuel is supplied from the common delivery pipe 131.

The injector 11 has a cylindrical housing 2.
The lower end surface of the valve body 22 is connected to the lower end of the valve body 22.
In FIG. 1, an injection hole 201 penetrating through the lower end wall 220 is opened, and fuel is injected from the injection hole 201 by the operation of a valve (not shown) provided in the valve body 22. A supply path (not shown) for supplying the fuel from the delivery pipe 131 into the valve body 22 is formed in the housing 21, and the upper end of the housing 21 has a fuel inlet 2.
It is 11. The fuel inlet 211 is fitted into the connection hole 1311 of the delivery pipe 131, and the fuel inlet 2
The liquid-tightness is maintained by the O-ring 24 between the side surface of the connector 11 and the inner wall surface of the connection hole 1311. A solenoid or the like for driving a valve is also provided in the housing 21. The solenoid is operated by an energization control signal input from a connector 212 protruding outward from a side surface of the housing 21 to inject and stop fuel injection. And.

A mounting hole 61 for mounting the injector 11 and the fuel guide 4 to the cylinder head 6 is stepped and penetrates the cylinder head 6, and has a small diameter on the intake passage side.

The injector 11 has an insulator 3 which is a rubber-made heat insulating holding member attached to the outer periphery of the valve body 22 and is held in a large diameter portion of a mounting hole 61 via the insulator 3. The insulator 3 is positioned by an annular step 213 projecting from the side surface of the valve body 22 of the injector 11.

The fuel guide 4 is formed by molding a heat conductive aminium material into a thick circular shape having a substantially hat-shaped cross section. The mounting hole 61 is closed at the tip end side of the valve body 22. The upper end flange 41 is sandwiched between the stepped surface of the mounting hole 61 and the lower end surface of the insulator 3.
When the fuel pressure in the delivery pipe 131 increases due to the operation of the fuel pump 15, the injector 11 is pressed downward by the fuel pressure, and the fuel guide 4 is strongly fixed to the cylinder head 6 together with the injector 11. An annular groove is formed in a side surface of the fuel guide 4 and an O-ring 5 is fitted into the annular groove to seal the space between the fuel guide 4 and the cylinder head 6 and maintain airtightness.

A through hole is formed in the fuel guide 4 at the position of the injection hole 201 of the injector 11 to form a fuel guide passage 401 for guiding fuel from the injection hole 201 to the combustion chamber.
The fuel is injected from an outlet 4011 of a fuel guide flow path 401 which is opened at the lower end surface 42 of the fuel guide 4.

The upper end surface of the fuel guide 4 has a shallow recess slightly larger in diameter than the lower end surface 221 of the injector valve body 22, and the step is such that the injector 11 is strong against the cylinder head 6 as described above. Even when it is fixed, the height is set so that a gap is secured between the stepped bottom surface 43 of the recess and the lower end surface 221 of the injector valve body.

The operation of the fuel supply device will be described. By the operation of the fuel pump 15, fuel is supplied to the injector 11 at a predetermined fuel pressure defined by the relief valve 16. When the injector 11 is opened, the fuel is injected from the injection hole 201 through the fuel guide passage 401 into the intake passage.

At this time, the reason why icing is considered is as follows.
This is in the vicinity of a fuel guide flow path outlet 4011 that is opened at the lower end surface 42 of the fuel guide 4 exposed to the air in the intake passage.

In the vicinity of the fuel guide flow path outlet 4011, the fuel flow through the fuel guide flow path 401 is from -10 ° C to -40 ° C.
The fuel guide 4 is made of an aluminum material having good heat conductivity, and the lower end surface 411 of the flange portion 41 is in close contact with the mounting hole step surface 611 as described above. 6 is integrated, heat is well transferred between the two surfaces 411 and 611 that are in close contact with each other, and even if the fuel guide flow path outlet 4011 and the fuel guide flange 41 are located on opposite sides, the fuel guide 4 A temperature gradient is hardly generated inside, and heat is satisfactorily transferred from the relatively high temperature cylinder head 6 to the vicinity of the fuel guide flow path outlet 4011. In addition, both surfaces 411 and 611 that are in close contact
Regulates heat transfer to the wall surface of the fuel guide flow path 401 including the vicinity of the fuel guide flow path outlet 4011, and
Heat corresponding to the area of 1,611 can be supplied.

Here, the area where the lower end surface 411 of the fuel guide flange receiving the heat from the cylinder head 6 is in contact with the mounting hole step surface 611 is defined as the area where the fuel is removed from the fuel guide 4. By setting the area sufficiently larger than the area of the inner wall surface of the fuel guide flow path 401 including the bottom surface 43, the fuel is passed on the both surfaces 411 and 611 and supplied to the inner wall surface of the fuel guide flow path 401. The generated heat tends to be more than the heat absorbed by the fuel on the inner wall surface of the fuel guide flow path 401, and the vicinity of the fuel guide flow path outlet 4011 is not excessively cooled to prevent icing. Can be. Also, it is desirable that the smaller the diameter of the fuel guide channel 401 that defines the area of the inner wall of the fuel guide channel 401 is, the smaller the heat removal area by the fuel is.
It is necessary to set in consideration of fuel circulation. That is,
Since the fuel is partially vaporized and in a gas-liquid mixed state in the fuel guide flow path 401, the volume is expanded. Therefore, it is preferable to secure the diameter of the fuel guide channel 401 so that the flow resistance of the fuel does not increase due to the volume expansion. This is because there is a possibility that the fuel injection amount or the like defined by the valve opening time of the injector 11 may be affected. According to the investigation by the inventors, it is desirable that the diameter is about φ1 to φ3.

In the fuel guide 4, heat is transported from the cylinder head 6 so that the vicinity of the fuel guide passage outlet 4011 is not excessively cooled.
Is fixed to the cylinder head 6 via the insulator 3, and since the insulator 3 is made of rubber having a low thermal conductivity, the heat transfer from the cylinder head 6 to the injector 11 itself is slightly suppressed. Thereby, the injector 11
A large amount of heat of the cylinder head 6 is not transmitted to itself,
It is possible to prevent fuel in the injector 11, particularly in the valve body 22, from being vaporized.

As described above, according to the present fuel supply device, prevention of icing and prevention of vaporization of fuel can be achieved at the same time, and the accuracy of fuel metering can be improved.

(Second Embodiment) FIG. 3 shows a fuel supply device of the present invention. In the first embodiment, the structure of the fuel guide is changed, and portions that operate substantially the same as in the first embodiment are given the same numbers, and differences from the first embodiment will be mainly described. .

In the first embodiment, the diameter of the fuel guide is slightly smaller than the diameter of the small diameter portion of the mounting hole 61 of the cylinder head 6, but the fuel guide 4A is substantially the same as the diameter of the small diameter portion of the mounting hole 61. At the time of assembly, it is attached to the cylinder head 6 by driving into the small diameter portion from the large diameter portion side of the mounting hole 61.

In this embodiment, the side surface 4 of the fuel guide 4A
4 and the side surface 612 of the mounting hole 61 are in close contact with each other, so that the heat transfer area between the cylinder head 6 and the fuel guide 4A is increased, and the O-ring (see FIG. 1) for maintaining airtightness can be eliminated. .

(Third Embodiment) FIG. 4 shows a fuel supply device of the present invention. In the second embodiment, the structure of the portion where the fuel guide passage is formed is changed, and the portions that operate substantially the same as in the second embodiment are given the same numbers, and The following description focuses on the differences.

The fuel guide 4B has basically the same structure as the fuel guide of the second embodiment. The diameter of the through hole 402 formed at the position of the injection hole 201 of the injector 11 is slightly larger than that of each of the above embodiments. Here, an inner pipe 71 as a flow path member is inserted. The inner pipe 71 is a cylindrical member having an inner diameter of about φ1 and an outer diameter slightly smaller than that of the through hole 402, and is preferably made of a material having a lower thermal conductivity than the outer pipe 42. Inside the inner pipe 71 is a fuel guide passage 401, and the inner pipe 71 is the innermost peripheral portion of the passage wall of the fuel guide passage 401. A flange portion 711 is provided at an upper end portion of the inner pipe 71, and the flange portion 711 is fitted into a concave portion 431 formed on the concave bottom surface 43 of the fuel guide 4B, and the inner pipe 71 is integrated with the fuel guide 4B. ing. At this time, an annular gap 403 is formed between the outer peripheral surface of the inner pipe 71 and the side surface of the through hole 402 of the fuel guide 4B.

In the present embodiment, the fuel guide flow path outlet 401
Heat is supplied from the cylinder head 6 to the vicinity of the lower end opening of the through hole 402 of the fuel guide 4B, which is near 1 to prevent icing, and has the following effect. That is, since the fuel guide passage 401 is formed in the inner pipe 71, the fuel flowing through the fuel guide passage 401 comes into contact with the inner pipe 71. Here, since the thermal conductivity of the inner pipe 71 is reduced, the heat loss due to the fuel flowing through the fuel guide flow path 401 is further suppressed, and icing can be more effectively prevented. Also,
By suppressing the heat loss by the fuel, it is not necessary to excessively supply the heat from the cylinder head 6 to the fuel guide 4B, and the vaporization of the fuel can be more suitably suppressed.

In this embodiment, the annular gap 403 is provided between the side surface of the through hole 402 of the fuel guide 4B and the side surface of the inner pipe 71. The annular gap portion 403 is a layer of air, and has a lower thermal conductivity than other portions of the fuel guide 4B. In other words, it becomes a heat transfer barrier that suppresses heat transfer between the inner peripheral side and the outer peripheral side. As a result, the portion of the fuel guide flow path 401 which is deprived of the circulating fuel is substantially limited to the inner pipe 71 which is the innermost portion of the flow path wall of the fuel guide flow path 401, and the heat capacity of the heat deprivation portion Becomes relatively small limited to the inner pipe 71. The amount of heat removed by the circulating fuel is suppressed. As a result, icing can be more favorably prevented, and fuel vaporization can be prevented.

The features of this embodiment can be applied to the configuration of the first embodiment.

(Fourth Embodiment) FIG. 5 shows a fuel supply device of the present invention. In the second embodiment, the structure of the fuel guide is changed, and portions that operate substantially the same as in the second embodiment are denoted by the same reference numerals, and differences from the second embodiment will be mainly described. .

The fuel guide 4C is formed by forming an annular deep groove coaxially with the fuel guide of the second embodiment in the vicinity of the fuel guide passage outlet 4011 on the lower end surface 42 side thereof. Like the annular gap 403 of the third embodiment, the annular gap 403A serves as a heat transfer barrier that suppresses heat transfer between the inner circumferential side and the outer circumferential side. This allows
The portion of the fuel guide flow path 401 which is deprived of the flowing fuel is substantially the innermost part of the flow path wall of the fuel guide flow path 401, that is, the cylindrical portion 4 on the inner circumference of the annular gap 403 </ b> A.
Limited to 21. The heat capacity of the heat removal portion is relatively small, limited to the cylindrical portion 421. Thereby, the amount of heat removed by the circulating fuel is suppressed. Further, since heat from the cylinder head 6 is transmitted more favorably at the outer peripheral portion than the annular gap portion 403A of the fuel guide 4C, the vicinity of the fuel guide passage outlet 4011 is prevented from being excessively cooled. As a result, icing can be more favorably prevented, and fuel vaporization can be prevented.

The features of this embodiment can be applied to the configuration of the first embodiment.

(Fifth Embodiment) FIG. 6 shows a fuel supply device of the present invention. In the second embodiment, the structure of the fuel guide is changed, and portions that operate substantially the same as in the second embodiment are denoted by the same reference numerals, and differences from the second embodiment will be mainly described. .

The fuel guide 4D has a slightly longer length than the fuel guide of the second embodiment, and a substantially lower half portion projects from the inner surface 62 of the cylinder head 6.

Since the flow rate of the intake air becomes relatively higher as the distance from the inner surface 62 of the cylinder head 6 increases, the fuel guide 4D
Is protruded from the inner surface 62, so that the fuel injected from the fuel guide passage outlet 4011 rides on the intake air flow, flows immediately downstream thereof, and leaves the fuel guide passage outlet 4011. As a result, it is suppressed that the injected fuel diffuses and reaches the vicinity of the fuel guide flow path outlet 4011 and loses heat from the vicinity. Further, the fuel guide 4D satisfactorily receives heat from the intake air flow in the cylinder at the protruding portion. Thereby, icing can be prevented more favorably.

The feature of this embodiment is the first, third and fourth parts.
It can also be applied in the configuration of the embodiment.

(Sixth Embodiment) FIG. 7 shows a fuel supply device of the present invention. In the second embodiment, the structure of the fuel guide is changed and a new member is added. Portions that operate substantially the same as in the second embodiment are denoted by the same reference numerals, and are different from the second embodiment. The explanation will focus on the points.

The fuel guide 4E has basically the same structure as the fuel guide of the second embodiment, and has an annular groove 45 surrounding the inlet 4012 of the fuel guide passage 401 in the concave bottom surface 43 formed on the upper end surface. The O-ring 52 is mounted on the O-ring. The O-ring 52 is sandwiched between the bottom surface 43 of the concave portion of the fuel guide and the lower end surface 221 of the injector.
An annular contact portion which is in elastic contact with the inner surface 3, 221 and in close contact with both surfaces 43, 221 is formed around the fuel guide passage outlet 4011 and the injection hole 201. As a result, the fuel ejected from the injection hole 201 flows into the fuel guide passage inlet 4012 without flowing to the outer peripheral side of the O-ring 52. Therefore, since the bottom surface 43 of the concave portion of the fuel guide 4E is not in contact with the fuel on the outer peripheral side with respect to the O-ring 52, the fuel is not removed from the fuel at this portion. Therefore,
A decrease in the temperature of the fuel guide 4E can be avoided, and icing can be more effectively prevented.

The features of this embodiment can be applied to the configurations of the first, third, fourth and fifth embodiments.

(Seventh Embodiment) FIGS. 8A and 8B
1 shows a fuel supply device of the present invention. The second embodiment differs from the second embodiment in the structure of the fuel guide. Parts that operate substantially the same as in the second embodiment are denoted by the same reference numerals, and differences from the second embodiment will be mainly described.

The fuel guide 4F has basically the same structure as the fuel guide of the second embodiment, and has a cross-shaped shallow groove 46 formed in the lower end surface 42 of the fuel guide passage outlet 4011 to reach the periphery of the lower end surface 42. The width of the groove 46 is substantially the same as the fuel guide flow path outlet 4011.

Since the groove 46 catches water condensed on the lower end surface 42 of the fuel guide, the free movement of water on the lower end surface 42 of the fuel guide is restricted.
It is possible to suppress the intrusion of water into the fuel guide channel 401 from 1. Thus, it is possible to prevent the water that has entered the fuel guide passage 401 from freezing while the internal combustion engine is stopped and closing the fuel guide passage outlet 4011, thereby preventing the startability at low temperatures from being deteriorated. it can.

The features of this embodiment can be applied to the configurations of the first, third, fourth, fifth, and sixth embodiments.

(Eighth Embodiment) FIG. 9 shows a fuel supply apparatus according to the present invention. In the first embodiment, substantially the same operation is obtained without using a fuel guide.
Portions that operate substantially the same as in the first embodiment are denoted by the same reference numerals, and differences from the first embodiment will be mainly described.

The mounting hole 61A for mounting the injector 11 is substantially the same as the mounting hole of each of the above embodiments except that the small diameter portion is omitted and only the large diameter portion is provided. Tip surface 22 of
A concave portion having a diameter slightly larger than that of the first concave portion is formed. The cylinder head 6A has a through hole opening below the mounting hole 61A at the stepped bottom surface 631 of the recess, and serves as a fuel guide passage 401.

The injector 11 is held in the mounting hole 61A via the insulator 3 in the same manner as in each of the above-described embodiments, and sandwiches the insulator 3 positioned by the annular step portion 213 of the injector 11 by the fuel pressure in the delivery pipe (not shown). The annular step upper surface 6 of the mounting hole bottom surface 63
32 and is fixed to the cylinder head 6A. At this time, the step of the concave portion formed on the mounting hole bottom surface 63 is set so that a gap is secured between the injector distal end surface 221 and the mounting hole concave bottom surface 631.

Since the cylinder head 6A is usually made of cast iron or the like having good thermal conductivity, the cylinder head 6A
Since a portion 6a of A surrounds the fuel guide flow path 401, substantially the same effect as the configuration of the second embodiment can be obtained. Since no fuel guide is required, the number of parts is reduced. In addition, in the configuration of each of the above embodiments using the fuel guide, the thermal conductivity can be controlled by selecting the material of the fuel guide, and the fuel guide flow path is formed in a separate part from the cylinder head, so that the manufacturing is easy. It is sufficient to appropriately determine which configuration is to be adopted depending on the required specifications.

(Ninth Embodiment) FIG. 10 shows a fuel supply apparatus according to the present invention. Portions that operate substantially the same as in the above-described embodiments are assigned the same numbers, and differences from the first embodiment will be mainly described. The injector 11A is connected to the housing 2
A valve body 22A having a valve 25 disposed at the lower end of the valve body 22
The injection hole plate 23 through which the injection hole 201 penetrates is attached to the lower end surface of the valve body 22A.

An inner adapter 72 and an outer adapter 4G are provided at the tip end of the injector 11A.
The inner adapter 72 and the outer adapter 4G are made of, for example, an aluminum material. The inner adapter 72 includes a lid portion 721 that is fitted to and covers the valve body 22A, which is the tip of the injector, and a tubular portion 722 that protrudes from the lower end surface. The lid 721 is a valve body 22A
And press-fitted to each other, and the tight contact portion between the lid portion 721 and the valve body 22A is kept liquid-tight. The tubular portion 722 is open at both ends, and the inner adapter 72 is connected to the valve body 22.
A, when it is fitted to the lower end surface 231 of the injection hole plate 23, which is the front end surface of the injector, the injection hole 201 is communicated with the inside of the cylindrical portion 722 and the injection hole 20.
The fuel guide flow path 401 guides the fuel injected from No. 1 to the intake passage.

The outer adapter 4G is a circular member slightly smaller in diameter than the lower small diameter half part of the mounting hole 61, similarly to the fuel guide of each of the above embodiments, and the upper end surface of the outer adapter 4G is smaller than the inner adapter 72. Large diameter hole 4
7 is formed, and the inner adapter 72 is inserted into the outer adapter 4G at the upper end 4a, which is the end on the injector side. Substantially injector 11
No contact with A. The outer adapter 4G has a through hole 402A through which the inner adapter tubular portion 722 is inserted.
Is formed. The through hole 402A has a slightly larger diameter than the inner adapter tubular portion 722, and an annular slight gap portion 403B is formed between the side surface of the inner adapter tubular portion 722 and the wall surface of the through hole 402A. In addition, a gap is secured between the lower end surface of the inner adapter cover 721 and the bottom surface 471 of the hole 47 of the outer adapter 4G.

The outer adapter 4G also has a flange portion 41 at the upper end, and the lower annular surface 411 of the flange portion 41 is in contact with the step surface 611 of the mounting hole 61. The insulator 3 is sandwiched between the inner adapter flange portion 7211 and the outer adapter flange portion 41, and the outer peripheral surface is in close contact with the side surface of the mounting hole 61.

Then, due to the pressure of fuel supplied from a delivery pipe (not shown) into the injector 11A, the outer adapter flange portion 41 comes into close contact with the stepped surface of the mounting hole 611, and the outer adapter flange portion 41
Good heat transfer to G.

Since the outer diameter of the outer adapter 4G is slightly smaller than the lower small diameter half of the mounting hole 61,
The heat transfer portion of the outer adapter 4G that receives heat from the cylinder head 6 is substantially limited to the flange portion 41. The amount of heat transfer from the cylinder head 6 is adjusted by the contact area between the outer adapter flange 41 and the mounting hole step surface 611, thereby suppressing the amount of heat transferred to the inner adapter 72.

In the present embodiment, the outer adapter 4
G is not in contact with the inner adapter 72, and the insulator 3 as a heat insulating member is interposed between the inner adapter 72 and the injector 11A. Therefore, the cylinder head 6
Is transferred from the outer periphery of the inner adapter tubular portion 722 to the inner adapter 72.

In the present embodiment, the outer adapter 4G surrounds the fuel guide passage 401, and the heat transmitted from the cylinder head 6 to the outer adapter 4G causes the peripheral edge of the through hole 402A near the fuel guide passage outlet 4011 to move. Excessive cooling can be suppressed. Also, a slight annular gap is formed between the inner adapter tubular portion 722 and the outer adapter 4G, and the fuel guide flow path 401
The heat removal part by the fuel flowing through the fuel guide passage 401
Inner adapter cylindrical portion 7 which is the innermost portion of the flow path wall
22 and the amount of heat removed by the circulating fuel is suppressed.
Thereby, icing can be prevented well,
Fuel vaporization can be prevented.

Since the inner adapter 72 and the outer adapter 4G are integrated, the injection hole 201 and the fuel guide passage 4
01 is constant. For example, in the structure of the first embodiment and the like, a dead volume is provided between the fuel guide 4 and the valve body 22 in the fuel guide passage 401 as described in the sixth embodiment. This causes an increase in heat transfer from the wall to the fuel. Here, if the space between the fuel guide 4 and the valve body 22 is reduced, the dead volume can be reduced. However, if the insulator 3 contracts in the vertical direction due to aging, the valve body 22 will not move.
Comes into contact with the fuel guide 4 and the amount of heat transferred from the fuel guide 4 to the valve body 22 sharply increases.
The fuel inside is vaporized. As described above, there is a trade-off between the reduction of the dead volume and the avoidance of contact between the fuel guide 4 and the valve body 4.

In this embodiment, since the inner adapter 72 in which the fuel guide passage 401 is formed is integrated with the injector 11A, the dead volume does not change. On the other hand, the depth of the hole 47 of the outer adapter 4G defines the contact margin with the inner adapter 72,
Since it has nothing to do with the size of the dead volume, it can be made considerably deeper in consideration of the settling of the insulator 3. Thus, it is possible to achieve both suppression of heat transfer from the fuel guide channel wall surface to the fuel and avoidance of contact between the injection hole 201 forming surface and the fuel guide (in the present embodiment, the outer adapter).

The insertion amount and the length of the inner adapter tubular portion 722 are determined by the inner adapter tubular portion 72.
The lower end surface of the outer adapter 4G is set so as not to protrude downward from the lower end surface of the outer adapter 4G even when the insulator 3 is slackened.
The lower end surface of the second adapter 2 is located at a position retracted further to the back side of the through hole 402A than the lower end surface of the outer adapter 4G. This is because if the inner adapter tubular portion 722 protrudes from the lower end surface of the outer adapter 4G, icing may occur at the protruding portion.

Further, since the positional relationship between the injection hole 201 and the fuel guide flow path 401 is constant, the injection characteristics are constant even if the injector 11A and the outer adapter 4G are displaced during assembly.

Further, since there is a margin for settling of the insulator 3, the material selection of the insulator 3 can be increased and the replacement time of the insulator 3 can be made longer.

(Tenth Embodiment) FIG. 11 shows a fuel supply device according to the present invention. In an internal combustion engine that uses liquefied fuel gas as fuel, attention is paid to the heat capacity of the fuel in order to prevent vaporization of the fuel in the injector, and the fuel supply device has a side feed configuration in which substantially the entire injector is located in the delivery pipe. In some cases, the injector is cooled by circulating fuel. In this embodiment, the present invention is applied to such a side-feed fuel supply device. Portions that operate substantially the same as in the above-described embodiments are assigned the same reference numerals, and differences from the above-described embodiments will be mainly described.

The delivery pipe 131A is provided with one cylindrical mounting portion 1312 having openings at both ends and protruding toward the cylinder head 6 across the pipe body 1311 extending in the cylinder arrangement direction, one for each cylinder. Is inserted with the injector 11B. The injector 11B includes an O-ring 531 for sealing between the injector 11B and the mounting portion 1312.
It is held by the mounting portion 1312 via 532, and closes the openings at both ends of the mounting portion 1312. Fuel flowing through the pipe body 1311 is supplied into the injector 11B from a supply port (not shown).

The mounting portion 1312 connected to the injector 11B via the O-rings 531 and 532 substantially forms a part of the injector 11B, and the mounting portion 1312 penetrates the cylinder head 6 via the insulator 3 provided on the outer periphery thereof. It is held in the hole 61.

An outer adapter 4H and an inner adapter 73 are provided at the tip end of the injector 11B.
The outer adapter 4H is made of, for example, an aluminum material, and the inner adapter 73 is made of a synthetic resin having a lower thermal conductivity than the outer adapter 4H. The inner adapter 73 is a stepped rod-shaped body having a narrowed lower end, and is fitted into a concave portion 222 formed on the lower end surface of the valve body 22A, which is the tip of the injector. Inner adapter 73
Is formed with a fuel guide passage 401 passing through the center thereof.
The fuel is guided from the injection hole 201 which is opened at the step bottom surface of the recess 222. Also in the present embodiment, since the inner adapter 73 in which the fuel guide channel 401 is formed is provided integrally with the injector 11B, the relative position between the outer adapter 4H and the inner adapter 73 changes due to settling of the insulator 3 or the like. Even the fuel guide channel 4
No. 01 has a constant shape and a constant position relative to the injection hole 201.

The outer adapter 4H has the same basic shape as that of the fuel guide of the first embodiment, and the upper flange portion 41 has the lower end surface of the insulator 3 and the mounting hole 6.
It is sandwiched between the first step surface 611. The upper end surface of the insulator 3 is in contact with the step surface of the delivery pipe mounting portion 1312, and the outer adapter flange portion 41 is pressed against the mounting hole step surface 611 via the insulator 3 by the pressing load of the delivery pipe 131A, and Heat is transferred well between the cylinder head 4H and the cylinder head 6.

The outer adapter 4H has a through hole 402B through which the small-diameter lower end 731 of the inner adapter 73 is inserted.
Surrounds 1 The through-hole 402B has a slightly larger diameter than the inner adapter small-diameter lower end 731, and a slight gap 403C is formed between the side surface of the inner adapter small-diameter lower end 731 and the wall surface of the through-hole 402B.

With this structure, the cylinder head 6
The peripheral portion of the through hole 402B of the outer adapter 4H, which is close to the fuel guide passage outlet 4011, is not excessively cooled by the heat transfer action from the fuel guide passage 4011. The lower end 731 of a certain inner adapter is made of a synthetic resin having a lower thermal conductivity than metal or the like, and the gap 403C is provided between the lower end 731 of the inner adapter and the outer adapter 4H, so that heat removal by fuel is prevented. Can be suppressed. Thereby, icing can be favorably prevented.

Since the inner adapter 731 does not contact the outer adapter 4H, the outer adapter 4H
It is possible to obtain substantially the same heat transfer suppressing effect even with a material such as the same kind of metal.

The configuration of the apparatus, such as the number of cylinders and fuel properties, is not limited to those described in the above embodiment.
It is optional as long as it does not contradict the spirit of the present invention.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a state in which an injector constituting a fuel supply device for a first internal combustion engine of the present invention is mounted on a cylinder head.

FIG. 2 is a diagram showing an overall configuration of a fuel supply device for the internal combustion engine.

FIG. 3 is a sectional view showing a state in which an injector constituting a fuel supply device for a second internal combustion engine of the present invention is mounted on a cylinder head.

FIG. 4 is a cross-sectional view showing a state in which an injector constituting a fuel supply device for a third internal combustion engine of the present invention is mounted on a cylinder head.

FIG. 5 is a sectional view showing a state in which an injector constituting a fuel supply device for an internal combustion engine according to a fourth embodiment of the present invention is mounted on a cylinder head.

FIG. 6 is a sectional view showing a state in which an injector constituting a fuel supply device for an internal combustion engine according to a fifth embodiment of the present invention is mounted on a cylinder head.

FIG. 7 is a sectional view showing a state in which an injector constituting a fuel supply device for an internal combustion engine according to a sixth embodiment of the present invention is mounted on a cylinder head.

FIG. 8A is a cross-sectional view showing a state in which an injector constituting a fuel supply device for an internal combustion engine according to a seventh embodiment of the present invention is mounted on a cylinder head, and FIG.
It is an arrow view.

FIG. 9 is a sectional view showing a state in which an injector constituting a fuel supply device for an internal combustion engine according to an eighth embodiment of the present invention is mounted on a cylinder head.

FIG. 10 is a cross-sectional view showing a state where an injector constituting a ninth internal combustion engine fuel supply device of the present invention is mounted on a cylinder head.

FIG. 11 is a sectional view showing a state in which an injector constituting a fuel supply device for an internal combustion engine according to a tenth embodiment of the present invention is mounted on a cylinder head.

[Explanation of symbols]

11, 11A, 11B Injector 12 LPG tank 13 Delivery line 131, 131A Delivery pipe 1312 Mounting part 14 Recovery line 15 Pump part 16 Relief valve 201 Injection hole 21 Housing 22, 22A Valve body 221 Valve body lower end face (injector tip face) ) 23 injection hole plate 231 injection hole plate lower end surface (injector tip surface) 3 insulator (holding member) 4, 4A, 4B, 4C, 4D, 4E, 4F fuel guide (heat conductive member) 4G, 4H outer adapter (heat) 4a Upper end (injector side end) 41 Flange part 411 Lower end face 43 Fuel guide concave step bottom (rear end face of heat conductive member) 401 Fuel guide flow path 402, 402A, 402B Through holes 403, 403A, 403B , 403C Annular gap 45 O-ring 46 Groove 6, 6A Cylinder head (partition wall) 6a Part 61 Mounting hole 611 Step surface 71 Inner pipe (flow path member) 72 Inner adapter (flow path member) 721 Lid 722 Cylindrical part 73 Inner adapter (flow path member) 731 Lower end

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court ゛ (Reference) F02M 69/04 F02M 69/04 A (72) Inventor Jun Yamada 14 Iwatani Shimowasukamachi, Nishio-shi, Aichi Pref. Inside the Japan Auto Parts Research Institute (72) Kenji Kanehara 14 Iwatani, Shimowasumi-machi, Nishio-shi, Aichi Prefecture Inside the Japan Auto Parts Research Institute (72) Inventor Kenji Hayashi 1 Toyota-cho, Toyota-shi, Toyota-shi, Aichi (72) Inventor Masaharu Wakabayashi 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation (72) Inventor Toshihiro Kawai 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation (72) Inventor Toru Sato 1-1-1, Kyowa-cho, Obu City, Aichi Prefecture Inside Aisan Industry Co., Ltd. (72) Inventor Takashi Okada Obu, Aichi Prefecture Within 1 Aisan Industry Co., Ltd. of chome address 1 Kyowa-cho (72) inventor Fusaji Omura Aichi Prefecture Obu Kyowa-cho, chome address 1 of 1 Aisan Industry Co., Ltd. in

Claims (8)

[Claims] 1. A mounting hole for an injector is formed in a partition wall through which intake air flows inside, the injector is held in the mounting hole, and an air-fuel mixture with the intake air is formed inside the partition wall from an injection hole opened at a tip end surface of the injector. In the fuel supply device for an internal combustion engine that supplies a fuel to be injected, an injector is held in the mounting hole via a holding member made of a heat insulating material, and the fuel injected from the injection hole of the injector is guided to the inside of the partition wall. A through hole reaching the inside of the partition is formed at the fuel guide channel forming position, and a part of the partition surrounding the fuel guide channel or a heat conductive member abutting on the partition. And the area of the wall surface of the fuel guide flow path, the heat transfer area of a part of the partition wall or a portion that regulates the heat transfer from the heat conductive member to the fuel guide flow path wall surface The fuel supply apparatus for an internal combustion engine, characterized in that remote set small. 2. The fuel supply device for an internal combustion engine according to claim 1, wherein a portion having low thermal conductivity is provided on an outer periphery of the fuel guide passage near the fuel guide passage. . 3. The fuel supply device for an internal combustion engine according to claim 2, wherein a through hole is formed in a part of the partition or the heat conductive member, and a flow path wall of the fuel guide flow path is formed in the through hole. A fuel supply device for an internal combustion engine, wherein a cylindrical member constituting the innermost peripheral portion of the internal combustion engine is inserted to make the low thermal conductivity portion. 4. The fuel supply device for an internal combustion engine according to claim 2, wherein an annular gap is formed on an outer periphery of an innermost peripheral portion of a flow path wall of the fuel guide flow path to serve as the low thermal conductivity portion. Engine fuel supply. 5. The fuel supply device for an internal combustion engine according to claim 1, wherein a front end surface of the injector in which the injection hole opens, a bottom surface of the mounting hole in which the through hole opens, or the thermal conductivity. A fuel supply device for an internal combustion engine, wherein an O-ring is provided between rear end surfaces of members to prevent fuel flowing from the injection hole to a fuel guide passage from flowing out of an outer periphery of the O-ring. 6. The fuel supply device for an internal combustion engine according to claim 1, wherein the partition has a structure through which the mounting hole penetrates, and the mounting hole is closed by the heat conductive member on a tip side of the injector. A flow path member integrally formed with the heat conductive member and a flow path member provided at a position facing the injection hole, the cylindrical portion having the inside as the fuel guide flow path protruding; A fuel supply device for an internal combustion engine having a gap formed therebetween. 7. A fuel supply device for an internal combustion engine according to claim 1, wherein a groove-shaped portion is formed on a part of the partition wall or the surface of the heat conductive member where an outlet of the fuel guide passage opens. A fuel supply device for an internal combustion engine having a recess. 8. The fuel supply device for an internal combustion engine according to claim 1, wherein a part of said partition or said heat conductive member is projected inside said partition.