JPH0797964A - Intake air heating device - Google Patents

Abstract

PURPOSE:To improve the heating efficiency of mixtured gas to be supplied form a carburetor and perform efficient vaporization of liquidified fuel under non-vaporized conditions. CONSTITUTION:This device is provided with a pair of radiation boards 11, 12 fitted to the inner circumferential wall part of intake pipe 2 which connects the intake passage of carburetor to the intake port of cylinder of an engine, through flange parts 11b, 12B formed integrally with plate parts 11A, 12A, and a PTC heat emmitting element 15 being pressure contacted with the upper faces of the flange parts 11B, 12B of the flanges 11, 12 of the radiation boards and generating heat with current supply from a battery. The plate parts 11A, 12A constituting the respective radiation boards 11, 12 are disposed at the positions where mixed gas or liquidified guel in the intake pipe 2 flows maximum, and the flange parts 11B, 12B constituting the respective radiation plates 11, 12 are partially protruded in the inward direction of the intake pipe 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake air heating device attached to a carburetor of an internal combustion engine, and more particularly to improving the heating efficiency of an air-fuel mixture supplied from the carburetor and efficiently vaporizing liquid fuel. In this case, the present invention relates to an intake air heating device.

[0002]

2. Description of the Related Art Conventionally, as an intake air heating device attached to a carburetor of an internal combustion engine mounted on a vehicle, for example, FIG.
There is a structure shown in FIG. 2, and a throttle valve 206 supported by a throttle shaft 206A is provided inside an intake passage 205 at an upper end portion of an intake pipe 204 connected to a cylinder head 201 of an engine 200 with bolts 202 and 203. The vaporizer 207 is connected to the heat insulator 2 via bolts 209 and 210 via the heat insulator 208.
08 and the inner peripheral wall of the upper end of the intake pipe 204 have an annular P
An intake air heating device 214 including a TC heating element 211, a cylindrical heat radiating pipe 212, a mounting member 213 and the like is provided.

The intake air heating device 214 has a relay 2 including a contact 216A and a coil 216B via a lead wire 215.
Power is supplied from the battery 219 connected to the fuse 16, the fuse 217, and the ground 218, and is connected to the ground 221 via the lead wire 220. In this case, the PTC heat generating element 211 and the heat radiating pipe 212 which form the intake air heating device 214 have the shapes shown in FIG. 26, and the mounting state of the PTC heat generating element 211 and the heat radiating pipe 212 to the heat insulator 208 is as shown in FIG. It is as shown in 27. Reference numerals 208A to 208D in the figure denote bolt mounting holes.

The lead wire 21 is connected to the intake air heating device 214.
When the battery 219 is energized via 5, 220, P
With the TC heating element 211 and the heat radiation pipe 212, the intake passage 2 is accompanied by the opening operation of the throttle valve 206 of the carburetor 207.
No. 05 to the intake pipe 204 is heated, the unvaporized liquid fuel flowing down the inner peripheral wall of the intake passage 205 is vaporized, and the intake port (not shown) of the cylinder head 201 of the engine 200 is evaporated. ).

An intake air heating device having a structure similar to that shown in FIG. 25 is, for example, Japanese Patent Publication 1-20303.
The one described in Japanese Patent Publication has been proposed. On the other hand, as described in, for example, Japanese Patent Laid-Open No. 60-237155, by forming a plurality of protrusions along the circumferential direction of the inner peripheral wall of the heat radiation pipe, the liquid fuel flowing down from the carburetor side is vaporized. An intake air heating device that has been developed is also being developed.

[0006]

However, the above-mentioned prior art has the following problems. The intake air heating device shown in FIG. 25 has a structure in which the entire circumference of the inner peripheral wall of the upper end portion of the intake pipe 204 is heated by the cylindrical heat radiating pipe 212, so that it flows from the carburetor 207 side to the intake pipe 204 side. As a result of heating the inner peripheral wall portion where the incoming air-fuel mixture does not pass so much, there is a problem that the heating efficiency of the air-fuel mixture is not very good. Further, since the heat radiation pipe 212 has a cylindrical shape, it is not possible to trap the liquid fuel that flows down to the heat radiation pipe 212 side along the inner peripheral wall surface of the carburetor 207, so that the heating efficiency of the liquid fuel is poor and the liquid fuel is liquid. The fuel cannot be atomized or vaporized sufficiently, and the liquid fuel has no resistance and the intake pipe 2
There was a problem of flowing into 04. In this case, when the accelerator opening of the vehicle becomes large, a large amount of liquid fuel flows down, which causes problems such as deterioration of drivability of the vehicle. Further, since the radiating pipe 212 is manufactured by plastic working, there is a problem that manufacturing is complicated, laborious, and costly. On the other hand, in the intake air heating device described in Japanese Patent Laid-Open No. 60-237155, the projecting piece is formed on the inner peripheral wall of the heat radiating pipe, but even with this structure, liquid fuel flowing down from the carburetor to the heat radiating pipe side is Therefore, there is a problem that the liquid fuel cannot be sufficiently trapped, and therefore the heating efficiency of the liquid fuel is poor and the liquid fuel cannot be sufficiently atomized or vaporized as in the above case.

[0007]

OBJECTS OF THE INVENTION The present invention can improve the disadvantages of the above-mentioned conventional examples, and in particular, can improve the heating efficiency of the air-fuel mixture supplied from the vaporizer and efficiently vaporize the liquid fuel in the non-vaporized state. It is an object of the present invention to provide an intake air heating device.

[0008]

According to a first aspect of the present invention, there is provided an electric heating body mounted on an inner peripheral wall side of an intake pipe connecting an intake passage of a carburetor and an intake port of a cylinder, and attached to the electric heating body. And a heating element that generates heat when energized from the outside, and the mixture heating or the unvaporized liquid fuel flowing from the vaporizer to the intake pipe is heated by the heating element and the heating element. The body is composed of at least two L-shaped plate-like members each having a protruding portion at an end thereof, and each plate-like member is provided with an inner peripheral wall side through which a relatively large amount of air-fuel mixture or liquid fuel in the intake pipe flows. Each of the plate-shaped members is mounted via the respective projecting portions, and the base end side of each projecting portion of each plate member is arranged so as to project inward of the intake pipe. There is. This is intended to achieve the above-mentioned object.

According to a second aspect of the present invention, there is provided an electric heating body mounted on an inner peripheral wall side of an intake pipe connecting an intake passage of a carburetor and an intake port of a cylinder, and an electric power attached to the electric heating body from outside. In an intake air heating device comprising a heating element that generates heat, and heating the air-fuel mixture or unvaporized liquid fuel flowing from the carburetor into the intake pipe by the electric heating element and the heating element, by pressing the electric heating element or the like. It is composed of at least two cylindrical members that are connected in the axial direction and have different inner diameters, and the cylindrical member having the smaller inner diameter is arranged on the downstream side of the intake pipe. Is adopted. This is intended to achieve the above-mentioned object.

According to a third aspect of the present invention, there is provided an electric heating body mounted on an inner peripheral wall side of an intake pipe connecting an intake passage of a carburetor and an intake port of a cylinder, and an electric power provided by the electric heating body from the outside. In an intake air heating device comprising a heating element for generating heat, wherein the mixture or the unvaporized liquid fuel flowing from the vaporizer into the intake pipe is heated by the heating element and the heating element, the heating element is a cylindrical member. And a projection having a predetermined width is formed along the inner peripheral edge of the cylindrical member at one end in the axial direction of the cylindrical member, and the electric heating element is provided with the projection forming side downstream of the intake pipe. The structure is such that it is placed toward the side. by this,
It is intended to achieve the above-mentioned purpose.

According to a fourth aspect of the present invention, there is provided an electric heating body mounted on an inner peripheral wall side of an intake pipe connecting an intake passage of a carburetor and an intake port of a cylinder, and an electric power attached to the electric heating body and supplied with electricity from the outside. In an intake air heating device comprising a heating element that generates heat, wherein the mixture or the unvaporized liquid fuel flowing from the vaporizer into the intake pipe is heated by the heating element and the heating element, the heating element is a top of a cone. A hollow member having a shape in which a portion including is cut in parallel to the bottom surface of the cone, and an opening portion of the hollow member having a large inner diameter is arranged toward the downstream side of the intake pipe. It consists of This is intended to achieve the above-mentioned object.

[0012]

According to the present invention as set forth in claim 1, the electric heating element is composed of at least two plate-like members each having a protruding portion at an end thereof, and each plate-like member is a mixture or liquid in the intake pipe. Since the structure is mounted on the inner peripheral wall side where a relatively large amount of fuel flows through each protruding portion, it is possible to intensively heat the inner peripheral wall side part where a mixture or liquid fuel in the intake pipe where a relatively large amount of fuel flows. As a result, the heating efficiency of the air-fuel mixture or the liquid fuel can be improved. Further, since the base end side of each projecting portion of each plate member is arranged so as to face the inside of the intake pipe, the liquid fuel in an unvaporized state that has flowed down from the carburetor to the intake pipe side. Can be accumulated in the above-mentioned protruding portion, and as a result, the liquid fuel can be surely vaporized by the heat generated from the heating element and the electric heating element.

According to the second aspect of the present invention, the electric heating element is composed of at least two cylindrical members having different inner diameters that are connected in the axial direction by press fitting or the like, and the inner diameter of each cylindrical member is Since the smaller cylindrical member is arranged on the downstream side of the intake pipe, the unvaporized liquid fuel that has flowed down from the carburetor to the intake pipe side is the thicker part of the cylindrical member with the smaller inner diameter. As a result, the liquid fuel can be surely vaporized by the heat generated from the heating element and the electric heating element.

According to the third aspect of the present invention, the electric heating element is composed of a cylindrical member, and the axially one end of the cylindrical member has a protrusion having a predetermined width along its inner peripheral edge. And the electric heating element is arranged with the protruding portion forming side facing the downstream side of the intake pipe, the liquid fuel in the unvaporized state that has flowed down from the carburetor to the intake pipe side is protruded from the heating element. As a result, the liquid fuel can be surely vaporized by the heat generated from the heating element and the electric heating element.

According to the fourth aspect of the present invention, the electric heating element is composed of a hollow member having a shape in which a portion including a top portion of a cone is cut in parallel to a bottom surface of the cone, and an inner diameter of the hollow member. Since the opening on the large side is located toward the downstream side of the intake pipe, the liquid fuel in the unvaporized state that has flowed down from the carburetor to the intake pipe side is the surface part on the large inside diameter side of the hollow member. As a result, the liquid fuel can be surely vaporized by the heat generated from the heating element and the electric heating element.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Each embodiment to which the intake air heating device of the present invention is applied will be described below with reference to the drawings.

(1) First embodiment. 1 to 3, the configuration of the intake air heating device and the carburetor / intake pipe of the first embodiment will be described. In the carburetor 1, the intake port of the cylinder head 3A of the engine 3 via the intake pipe 2 ( (Not shown), the carburetor 1 is
The intake passage 4 and a throttle valve 6 that is supported by a throttle shaft 5 and that performs a valve opening / closing operation are provided in a substantially central portion of the intake passage 4. The upper portion of the intake passage 4 of the carburetor 1 communicates with the atmosphere via an air cleaner (not shown), and an injector (not shown) is provided inside the intake passage 4.
Is used to inject fuel (eg, gasoline).

Between the lower end of the carburetor 1 and the upper end of the intake pipe 2, there are, for example, four resin heat insulators 7 each having the shape shown in FIG. 3 and provided with bolt holes 7A to 7D. Bolts 8 and 9 and washers 8A and 9A (other bolts and washers are not shown). On the inner peripheral wall of the heat insulator 7, a pair of heat dissipation plates 11 and 12 having the shape shown in FIG. The heat dissipation plate 11 is integrally formed of a rectangular plate 11A and a semicircular flange 11B.
2 is integrally formed from a rectangular plate 12A and a semi-circular collar 12B.

The heat radiating plate 11 is fixed by rivets to the mounting portion 10 of the heat insulator 7 via a mounting member 13 having a rivet hole 13A provided in the collar portion 11B. Similarly, the heat radiating plate 12 is fixed to the collar portion 12B. Rivet hole 14 provided
It is fixed by rivets to the mounting portion 10 of the heat insulator 7 via the mounting member 14 having A. In this case, the collar portion 11 is attached to the mounting portion 10 of the heat insulator 7.
B and 12B are provided with a groove portion to be engaged, and the groove portion and the collar portion 1
It is also possible to fix the heat sinks 11 and 12 via 1B and 12B.

Here, the arrangement relationship between the heat radiating plates 11 and 12 with respect to the heat insulator 7 will be described. When the throttle valve 6 of the carburetor 1 is opened (see FIG. 2), the air-fuel mixture K is supplied to the throttle valve 6 as well. Flows into the intake pipe 2 side through a gap formed between both end sides of the intake passage 4 and the inner peripheral wall of the intake passage 4, so that a large amount of the air-fuel mixture K in the inner peripheral wall of the intake pipe 2 on the carburetor mounting side. Plate portions 11A and 12B in the flowing portion
The heat radiating plates 11 and 12 are mounted so that is positioned. That is, the heat radiating plates 11 and 12 are the plate body parts 11A and 12A.
Is arranged so that the plate surface thereof is parallel to the throttle shaft 5.

Further, the ceramics annular PTC heating element 15 shown in FIG. 1 is pressed against the upper surfaces of the flange portions 11B and 12B of the heat dissipation plates 11 and 12 mounted on the inner peripheral wall of the heat insulator 7. . In this case, the heat sinks 11, 1
The second brim portions 11B and 12B are arranged such that the portions other than the pressure contact portion of the PTC heating element 15 protrude toward the inner side of the intake pipe 2. The radiator plates 11 and 12 and the PTC heating element 15 described above constitute an intake air heating device. In addition, the intake pipe 2
Is bent from below the heat dissipation plate 11, and its axial end portion is attached to the cylinder head 3A of the engine 3 with bolts 16 and 17.
And is fixed by washers 16A and 17A.

The pair of electrodes attached to the heat sinks 11 and 12 and the PTC heating element 15 are connected to the relay 18 for turning on / off the energization, which is composed of the contact 18A and the coil 18B, the fuse 19, and the earth 20 on the negative side. A lead wire 22 connected to a battery 21 whose terminals are grounded, and a lead wire 24 grounded to a ground 23 are respectively connected. PTC
The heating element 15 is adapted to generate heat when energized by the battery 21.

Next, the operation of the first embodiment constructed as described above will be described.

When fuel is injected into the intake passage 4 of the carburetor 1 by an injector (not shown), the atomized mixture K of fuel and air K is accompanied by the opening operation of the throttle valve 6.
It is supplied to the intake port of the cylinder of the engine 3 via the intake pipe 2. In this case, the mixture K is as shown in FIG.
It passes through a gap formed between both ends of the throttle valve 6 and the inner peripheral wall of the intake passage 4, and flows into the intake pipe 2 side.

Further, the PTC heating element 15 mounted on the inner peripheral wall of the heat insulator 7 generates heat when electricity is supplied from the battery 21, and the heat generated from the PTC heating element 15 is conducted to the heat radiating plates 11 and 12. In this case, the heat sink 1
1, 12 are arranged so that the plate portions 11A, 12A are located in the portion of the inner peripheral wall of the intake pipe 2 on the side where the carburetor 1 is attached, where a large amount of the air-fuel mixture K flows. The parts can be intensively heated by the heat generated from the plate parts 11A and 12A, and as a result, the heating efficiency of the air-fuel mixture can be improved.

Further, the collar portions 11B, 1 of the heat sinks 11, 12 are
2B is arranged so that the portion other than the attachment portion to the heat insulator 7 protrudes inward of the intake pipe 2, so that it is completely atomized or vaporized inside the carburetor 1 at the initial stage of starting the engine 3, for example. The liquid fuel that has flowed down without being stored can be stored in the collar portions 11B and 12B of the heat sinks 11 and 12, and as a result, the PTC heating element 15 and the heat sink 1
The liquid fuel can be surely atomized or vaporized by the heat generated from the collar portions 11B and 12B of 1 and 12. As a result, it is possible to prevent the liquid fuel from flowing down to the intake pipe 2.

The heat radiating plates 11 and 12 are composed of the plate body 11
Since it has a simple shape composed of A, 12A and the collar portions 11B, 12B, it can be easily manufactured by, for example, press molding, and thus cost can be reduced.

In this case, in the first embodiment, the heat sink 1
FIG. 1 shows the vertical dimension of the plate body portions 11A and 12A of 1 and 12.
And the plate body portions 11A, 1 having the dimensions shown in FIG.
If the vertical dimension of 2A is made longer, it is possible to further improve the heating efficiency of the air-fuel mixture, and thus it is possible to improve the drivability of the vehicle equipped with the engine 3. Further, the shapes of the heat dissipation plates 11 and 12 are not limited to those shown in FIG.

Next, each modification of the first embodiment will be described.

FIG. 4 shows the structure of a heat radiating plate 25 according to a first modification. The heat radiating plate 25 is integrally formed from a rectangular plate body portion 25A and a semi-circular collar portion 25B and has a collar portion. Two
A half-moon shaped hole portion 25C is formed in 5B to serve as a through hole for the air-fuel mixture flowing from the vaporizer side. As a result, the resistance of the collar portion 25B of the heat dissipation plate 25 to the intake air flow is reduced.

FIG. 5 shows the structure of a heat radiating plate 26 according to a second modification. The heat radiating plate 26 is integrally formed from a rectangular plate body portion 26A and a semicircular flange portion 26B, and also has a flange portion. Two
6B is provided with a half-moon shaped hole portion 26C for forming a through hole for the air-fuel mixture flowing from the vaporizer side.
A metal mesh 26D, for example, is attached to 6C. As a result, the resistance of the flange portion 26B of the heat dissipation plate 26 to the intake air flow is reduced.

FIG. 6 shows the structure of a heat radiating plate 27 according to a third modification. The heat radiating plate 27 is integrally formed of a rectangular plate body portion 27A and a semi-circular brim portion 27B, and these plates are also formed. The body portion 27A and the collar portion 27B are formed as a metal mesh. As a result, the heat radiation area of the heat radiation plate 27 is expanded, and liquid fuel is easily accumulated in the innumerable mesh portions of the heat radiation plate 27 to promote atomization or vaporization. Also in the first to third modifications, the heat radiation plate can be press-molded.

(2) Second embodiment. First, the structure of the heat dissipation pipe 30 in the second embodiment will be described with reference to FIGS. 8 to 10.
It is configured to include a cylindrical first pipe 31 having a flange 31A and a cylindrical second pipe 32 press-fitted into the inner peripheral wall of the first pipe 31. In this case, the second
The pipe 32 is press-fitted in the lower half of the first pipe 31. The heat radiation pipe 30 and the PTC heating element 15 described later constitute an intake air heating device. Reference numeral 32A in FIG. 9 indicates a step portion corresponding to the plate thickness portion of the second pipe 32.

Next, the structure of the carburetor equipped with the intake air heating device and the intake pipe will be described with reference to FIG. 7. The structure other than the heat radiation pipe 30 is the same as that of the first embodiment. That is, the upper end portion of the intake pipe 36 connected to the engine 33 by the bolts 34, 35 and the washers 34A, 35A is connected to the intake passage 38 via the heat insulator 37.
And a carburetor 40 equipped with a throttle valve 39
1, 42 and washers 41A, 42A are connected.

On the inner peripheral wall of the heat insulator 37,
The heat radiation pipe 30 is attached to the mounting portion 43 via the flange portion 31A of the first pipe 31, and an annular PTC heating element 44 made of ceramics is provided on the upper surface of the flange 31A.
Is fixed. Radiating pipe 30 and PTC heating element 4
A pair of electrodes attached to 4 is connected to a lead wire 49 to which a relay 45 including a contact point 45A and a coil 45B for turning on and off, a fuse 46, a ground 47 and a battery 48 whose negative terminal is grounded are connected. , And a lead wire 51 which is grounded to the ground 50, respectively.

According to the second embodiment, the radiator pipe 30
Is composed of the first pipe 31 attached to the inner peripheral wall of the heat insulator 37 and the second pipe 32 press-fitted into the inner peripheral wall of the first pipe 31, so that the carburetor is, for example, in the initial stage of starting the engine 33. The liquid fuel that has flowed down without being completely atomized or vaporized inside 40 can be stored in the step portion 32A corresponding to the plate thickness portion of the second pipe 32, and as a result, the PTC heating element 44 and the heat radiation pipe 30.
The liquid fuel can be reliably atomized or vaporized by the heat generated from the liquid fuel. This can improve the heating efficiency of the liquid fuel and prevent the liquid fuel from flowing down to the intake pipe 36.

(3) Third embodiment. First, the structure of the heat dissipation pipe 55 and the assembled state of various members including the heat dissipation pipe 55 with respect to the heat insulator in the third embodiment will be described with reference to FIG. 12. The heat dissipation pipe 55 includes a cylindrical main body 55A and a main body 55A. A plurality of flanges 5 projecting from one axial edge of the portion 55A to the outer periphery.
5B is integrally formed, and these main body 55A
The collar portion 55B is formed as a metal mesh. The heat radiation pipe 55 and the PTC heating element 57 described later constitute an intake air heating device. In this case, for convenience of description, FIG. 12 is shown with the top and bottom reversed.

The heat insulator 56 has bolt holes 5
6A to 56D, a heat radiation pipe 55, a pair of circular electrodes PTC heating element 57 made of ceramics, a pair of circular electrodes 58 and 59 each having mounting portions 58A and 59A, and a circular copper plate 60. Hole 56E and electrodes 58 and 59
And lead portions 61F and 62G that are connected to the insertion portions 56F and 56G, respectively.

The heat radiating pipe 55, the PTC heating element 57, the pair of electrodes 58 and 59, and the copper plate 60 are riveted in a state in which the arrangement shown in FIG. 12 is reversed with respect to the hole 56E of the heat insulator 56. It is designed to be fixed via (not shown). In this case, in order to prevent the ceramic PTC heating element 57 from being damaged by the collar portion 55B of the heat radiating pipe 55 made of a metal mesh due to, for example, vibration during traveling of a vehicle equipped with an engine described later, Between the collar portion 55B and the PTC heating element 57, a copper plate 6 that is soft and has excellent thermal conductivity and electrical conductivity
It is designed to insert 0.

Next, the structure of the carburetor equipped with the intake air heating device, the intake pipe, and the like will be described with reference to FIG. 11. The structure other than the radiation pipe 55 is substantially the same as that of the first embodiment. That is, an intake pipe 66 is connected to the intake port 63B mounted on the cylinder head 63A of the engine 63 by bolts 64, 65 and washers 64A, 65A, and the heat insulator 5 is attached to the upper end of the intake pipe 66.
6, the carburetor 69 having the intake passage 67 and the throttle valve 68 is connected to the bolts 70, 71 and the washers 70A, 7
It is connected by 1A.

On the inner peripheral wall of the heat insulator 56,
The heat radiation pipe 55 is attached through the collar 55B,
An electrode 58 is fixed to the lower surface of the collar portion 55B, and the collar portion 55B
A PTC heating element 57 is fixed on the upper surface of B via a copper plate 60, and an electrode 59 is attached on the upper surface of the PTC heating element 57.
Is fixed. The electrodes 59 and 58 include a contact 7A and a coil 72B for energization on / off relay 7
2, a fuse 73, a ground wire 74, a lead wire 62 connected to a battery 75 whose negative terminal is grounded, and a ground wire 61 connected to a ground wire 61.

According to the third embodiment, since the heat dissipation pipe 55 is made of a metal mesh, the heat dissipation pipe 55 is used.
And the liquid fuel can be easily accumulated in the innumerable mesh portions of the heat dissipation pipe 55.
As a result, the liquid fuel flowing down from the vaporizer 69 can be reliably atomized or vaporized by the heat radiation pipe 55. This can improve the heating efficiency of the liquid fuel and prevent the liquid fuel from flowing down to the intake pipe 66.

In this case, in the third embodiment, the wire diameter and mesh size of the metal mesh forming the heat dissipation pipe 55 can be set to arbitrary dimensions, but the wire diameter is reduced to form a mesh. By making fine, it is possible to further improve the heating efficiency. In addition, the collar portion 55 of the heat dissipation pipe 55
The shape of B is not limited to that shown in the figure.

(4) Fourth embodiment. The structure of the heat radiating pipe in the fourth embodiment will be described with reference to FIGS. 13 and 14. The heat radiating pipe 80 is composed of a cylindrical member having a flange 80A and has an end face opposite to the flange 80A forming side. A circular hole portion 80B is formed in the inner surface of the heat dissipation pipe 80, and the inner peripheral edge side of the end surface of the heat dissipation pipe 80 is formed as an annular step portion 80C. The heat radiating pipe 80 is mounted on the inner peripheral wall of the heat insulator via the flange 80A as in the above-described embodiments. In this case, when the heat radiation pipe 80 is mounted, the stepped portion 80C is located inside the carburetor mounting side of the intake pipe.

According to the fourth embodiment, the heat radiation pipe 80
Is provided with an annular step portion 80C on the end surface opposite to the side where the flange 80A is formed, so that the liquid fuel that has completely atomized or flowed down without being vaporized inside the carburetor is radiated from the heat radiation pipe. It can be stored in the stepped portion 80C of 80, and can be reliably atomized or vaporized by the heat generated from the PTC heating element (not shown) and the heat radiation pipe 80.
This can improve the heating efficiency of the liquid fuel and prevent the liquid fuel from flowing down to the intake pipe.

Next, a modified example of the fourth embodiment will be described.

FIG. 15 shows a radiation pipe 81 according to the first modification.
In the heat dissipation pipe 81 having the same configuration as that of the fourth embodiment, the cylindrical portion other than the flange 81A is formed of a metal mesh. As a result, the heat dissipation pipe 81
In addition to increasing the heat radiation area in the above, the liquid fuel is easily accumulated in the innumerable mesh portions of the heat radiation pipe 81 to promote atomization or vaporization. In this case, it is possible to form only the stepped portion 81C of the heat dissipation pipe 81 in a mesh shape or to form a plurality of small holes in the stepped portion 81C, and the same effect as described above can be obtained.

FIG. 16 shows a heat radiation pipe 82 according to the second modification.
The heat-dissipating pipe 82 having the same shape as that of the fourth embodiment is provided with knurled grooves on its inner peripheral wall. In the figure, reference numeral 82A indicates a flange, and reference numeral 82C indicates a step portion. As a result, the liquid fuel is easily accumulated in the innumerable groove portions of the heat radiation pipe 82 to promote atomization or vaporization.

FIG. 17 shows a heat radiation pipe 83 according to the third modification.
In the lower part of the heat dissipation pipe 83, a plurality of substantially triangular notches 83B ... And stepped parts 83C ... Are formed along the peripheral direction. Reference numeral 83A in the drawing indicates a flange. Thereby, the step portion 83 of the heat dissipation pipe 83
The resistance of C to the intake flow is reduced.

FIG. 18 shows a heat radiating pipe 84 according to the fourth modification.
In the lower portion of the heat radiation pipe 84, for example, four substantially triangular notches 84B ...
And step portions 84C ... Are formed. Reference numeral 84 in the figure
A indicates a flange. As a result, the liquid fuel is easily accumulated in the step portion 84C of the heat radiation pipe 84 to promote atomization or vaporization.

FIG. 19 shows a heat radiating pipe 85 according to the fifth modification.
The heat dissipating pipe 85 is obtained by dividing a member having the same shape as that of the fourth embodiment into four parts.
D, second member 85E, third member 85F, fourth member 85G
It consists of In the figure, reference numeral 85A indicates a flange, reference numeral 85B indicates a hole, and reference numeral 85C indicates a step. This allows
The liquid fuel is easily accumulated in the step portion 85C of the heat radiating pipe 85 to promote atomization or vaporization, and the resistance of the step portion 85C to the intake air flow is reduced.

(5) Fifth embodiment. First, the structure of the heat dissipation member 86 in the fifth embodiment is shown in FIG.
To explain based on 1, the dish-shaped heat dissipation member 86 has a substantially annular body portion 86A having a shape obtained by cutting a portion including the top portion of the cone with a plane parallel to the bottom surface of the cone, and the body portion 86A. The flange portion 86B integrally formed is provided. In this case, the outer diameter of the main body portion 86A of the heat dissipation member 86 is set to be smaller than the inner diameter of the intake passage 92 of the carburetor 94 described later.

Next, the structure of the carburetor equipped with the intake air heating device and the intake pipe will be described with reference to FIG. 20. The structure other than the heat radiating pipe 86 is the same as that of the first embodiment. That is, the bolts 88, 89 and the washer 8 are attached to the intake port 87B of the cylinder head 87A of the engine 87.
The intake pipe 90 is connected by 8A and 89A.
A carburetor 94 having an intake passage 92 and a throttle valve 93 is connected to the upper end of the through a heat insulator 91 by bolts 95, 96 and washers 95A, 96A.

On the inner peripheral wall of the heat insulator 91,
The heat dissipation member 86 is mounted via the flange portion 86B with the main body portion 86A facing upward, and the PTC heating element 97 is fixed to the upper surface of the flange portion 86A of the heat dissipation member 86. The pair of electrodes attached to the heat radiating member 86 and the PTC heating element 97 include a contact 98A and a coil 98B for energization on / off relay 98, a fuse 99,
Battery 10 with the negative terminal grounded to earth 100
The lead wire 102 to which 1 is connected, and the lead wire 104 which is grounded to the earth 103 are respectively connected.

According to the fifth embodiment, the heat dissipation member 86 is
The heat radiating member 86 is composed of an annular main body portion 86A having an outer diameter smaller than the inner diameter of the intake passage 92 of the carburetor 94 and a flange portion 86B, and the heat radiating member 86 is placed with the main body portion 86A facing upward. Since the structure is attached to the inner peripheral wall of 91, the liquid fuel that has not been sufficiently heated by the PTC heating element 97 and has flowed down can be disposed.
6 can be accumulated on the upper surface of the flange portion 86B, and can be reliably atomized or vaporized by the heat generated from the heat radiation pipe 86. This can improve the heating efficiency of the liquid fuel and prevent the liquid fuel from flowing down to the intake pipe.

Next, a modification of the fifth embodiment will be described.

FIG. 22 shows the mounting state of the heat radiating member according to the first modified example. The heat radiating member 105 having the same shape as that of the fifth embodiment is mounted on the inner peripheral wall of the heat insulator 106 to form an annular PTC heating element 107. It is arranged on the upper surface of. In the figure, reference numerals 108 and 109 are lead wires, and reference numeral 9
Reference numeral 0'denotes an intake pipe and reference numeral 94 'denotes a carburetor.

FIG. 23 shows the mounting state of the heat radiating member according to the second modification. Two heat radiating members 110, 11 having the same shape as the fifth embodiment and having different inner diameters at the upper end portions are shown.
1 is arranged on the upper surface and the lower surface of an annular PTC heating element 113 mounted on the inner peripheral wall of the heat insulator 112. In this case, by making the inner diameter of the upper end portion of the heat dissipation member 110 larger than the inner diameter of the upper end portion of the heat dissipation member 111, the scattered liquid fuel can be disposed below the heat dissipation member 111.
Can be trapped at. Reference numerals 114 and 115 in the figure
Is a lead wire, reference numeral 90 ″ is an intake pipe, and reference numeral 94 ″ is a carburetor.

FIG. 24 shows the mounting state of the heat radiating member according to the second modified example. Two heat radiating members 116 and 11 having the same shape as the fifth embodiment and having different inner diameters at the upper end portions are shown.
7 are arranged on the upper and lower surfaces of two annular PTC heating elements 119 and 120, which are mounted in layers on the inner peripheral wall of the heat insulator 118. In this case, by making the inner diameter of the upper end of the heat dissipation member 116 larger than the inner diameter of the upper end of the heat dissipation member 117, the scattered liquid fuel can be trapped by the lower heat dissipation member 117. In the figure, reference numerals 121, 122 and 123 are lead wires, and reference numeral 9
Reference numeral 0 ′ ″ denotes an intake pipe, and reference numeral 94 ′ ″ denotes a carburetor. In this case, the PTC heating elements 119 and 120 are connected in parallel, but series connection is also possible.

In this case, in the fifth embodiment and each modification, the surface of the heat dissipation member is knurled, the heat dissipation member is formed of a metal mesh, or the heat dissipation member is exposed to the intake passage. It is also possible to provide a stepped portion in the portion, form the exposed portion of the heat dissipation member to the intake passage in a curved surface, or form a plurality of holes in the exposed portion of the heat dissipation member to the intake passage. Thereby, the residence time of the liquid fuel with respect to the heat dissipation member can be lengthened, and atomization or vaporization can be promoted.

[0061]

As described above, according to the intake air heating apparatus of the present invention as set forth in claim 1, the electric heating element is composed of at least two L-shaped plate-like members having projecting portions at their ends. In addition, since each plate-shaped member is mounted through the protruding portion on the inner peripheral wall side where a relatively large amount of air-fuel mixture or liquid fuel flows in the intake pipe, the air-fuel mixture or liquid fuel in the intake pipe is compared. It is possible to intensively heat the inner peripheral wall side portion where a large amount of air flows, and as a result, it is possible to improve the heating efficiency of the air-fuel mixture or liquid fuel. Also,
Since the base end side of each projecting portion of each plate-shaped member is arranged so as to face the inside of the intake pipe, the unvaporized liquid fuel that has flowed down from the carburetor to the intake pipe is described above. The liquid fuel can be reliably vaporized by the heat generated from the heating element and the electric heating element.

According to the intake air heating device of the present invention as defined in claim 2, the electric heating element is composed of at least two cylindrical members having different inner diameters which are axially connected to each other by press fitting or the like. The cylindrical member with the smaller inner diameter is placed on the downstream side of the intake pipe, so that the liquid fuel in the unvaporized state that has flowed down from the carburetor to the intake pipe has the smaller inner diameter. The liquid fuel can be accumulated in the plate thickness portion of the plate-shaped member, and as a result, the liquid fuel can be surely vaporized by the heat generated from the heating element and the electric heating element.

According to the intake air heating device of the present invention as defined in claim 3, the electric heating element is composed of a cylindrical member, and the cylindrical member is provided at one axial end portion along the inner peripheral edge thereof. The structure is such that a protrusion having a predetermined width is formed and the electric heating element is arranged with the protrusion forming side facing the downstream side of the intake pipe, so that the unvaporized liquid fuel that has flowed down from the carburetor to the intake pipe side. Can be accumulated in the protruding portion of the electric heating element, and as a result, the liquid fuel can be surely vaporized by the heat generated from the heating element and the electric heating element.

Further, according to the fourth aspect of the present invention, the electric heating body is composed of a hollow member having a shape in which a portion including the top of the cone is cut in parallel to the bottom surface of the cone. At the same time, since the opening of the hollow member with the larger inner diameter is arranged toward the downstream side of the intake pipe, the liquid fuel in the unvaporized state that has flowed down from the carburetor to the intake pipe side can be The liquid fuel can be accumulated in the surface portion on the large side, and as a result, the liquid fuel can be surely vaporized by the heat generated from the heating element and the electric heating element.

Further, in the intake air heating device of the present invention, when all or part of the electric heating element is formed as a mesh member made of metal or the like, it is possible to increase the heat radiation area of the electric heating element and The liquid fuel can be easily stored in the mesh part of the body, and as a result, the unvaporized liquid fuel that has flowed down from the carburetor to the intake pipe side can be stored on the surface part of the hollow member where the inner diameter is large. As a result, the liquid fuel can be surely vaporized by the heat generated from the heating element and the electric heating element.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of a pair of heat sinks and a PTC heating element in a first embodiment to which the present invention is applied.

FIG. 2 is a sectional view with a part omitted showing the configuration of a carburetor equipped with an intake air heating device and an intake pipe in the first embodiment.

FIG. 3 is a heat insulator and 1 in the first embodiment.
It is explanatory drawing which shows the attachment state with a pair of heat sink and a PTC heat generating body.

FIG. 4 is a perspective view of a heat dissipation plate in a first modified example of the first embodiment.

FIG. 5 is a perspective view of a heat dissipation plate in a second modification of the first embodiment.

FIG. 6 is a perspective view of a heat dissipation plate in a third modification of the first embodiment.

FIG. 7 is a sectional view with a part omitted showing a configuration of a carburetor equipped with an intake air heating device and an intake pipe in the second embodiment.

FIG. 8 is a perspective view of a heat dissipation pipe in the second embodiment.

FIG. 9 is a first part of a heat dissipation pipe according to a second embodiment.
It is explanatory drawing which shows the attachment state of a 2nd pipe.

FIG. 10 is a sectional view of a heat dissipation pipe in the second embodiment.

FIG. 11 is a cross-sectional view with a part omitted showing the configuration of a carburetor equipped with an intake air heating device and an intake pipe in the third embodiment.

FIG. 12 is an explanatory diagram showing a state in which a heat radiating pipe, a PTC heating element and the like are attached to the heat insulator in the third embodiment.

FIG. 13 is a perspective view of a heat dissipation pipe according to a fourth embodiment.

FIG. 14 is a cross-sectional view of a heat dissipation pipe in the fourth embodiment.

FIG. 15 is a perspective view of a heat dissipation pipe in a first modified example of the fourth embodiment.

FIG. 16 is a perspective view of a heat dissipation pipe in a second modification of the fourth embodiment.

FIG. 17 is a perspective view of a heat dissipation pipe in a third modified example of the fourth embodiment.

FIG. 18 is a perspective view of a heat dissipation pipe in a fourth modified example of the fourth embodiment.

FIG. 19 is a perspective view of a heat dissipation pipe in a fifth modified example of the fourth embodiment.

FIG. 20 is a cross-sectional view showing a configuration of a carburetor equipped with an intake air heating device, an intake pipe, and the like, part of which is omitted, in the fifth embodiment.

FIG. 21 is a perspective view of a heat dissipation member in the fifth embodiment.

FIG. 22 is an explanatory diagram showing a mounted state of a heat dissipation member in a first modification of the fifth embodiment.

FIG. 23 is an explanatory view showing a mounted state of a heat dissipation member in a second modified example of the fifth embodiment.

FIG. 24 is an explanatory diagram showing a mounted state of a heat dissipation member in a third modified example of the fifth embodiment.

FIG. 25 is a cross-sectional view showing a configuration of a carburetor equipped with an intake air heating device, an intake pipe, and the like in the conventional example, with some parts omitted.

FIG. 26 is an explanatory view showing a mounting state of a heat radiating pipe and a PTC heating element in a conventional example.

FIG. 27 is an explanatory view showing a mounting state of a heat insulator, a heat radiating pipe, and a PTC heating element in a conventional example.

[Explanation of symbols]

1,40,69,94 Vaporizer 2,36,66,90 Intake pipe 3,33,63,87 Engine 4,38,67,92 Intake passage 7,37,56,91 Heat insulator 11,12 As an electric heating element Radiator plate 15,44,57,97 PTC heating element as heating element 30,55,80,81,82,83,84,85 Radiating pipe as heating element 86,105,110,111,116,117 Electric heating Heat dissipation member as body

Claims (5)

[Claims] 1. An electric heating body mounted on an inner peripheral wall side of an intake pipe connecting an intake passage of a carburetor and an intake port of a cylinder, and a heating body attached to the electric heating body and generating heat by energization from the outside. An intake air heating device comprising: an electric heating element and a heating element for heating a mixture gas or an unvaporized liquid fuel flowing from the vaporizer to the intake pipe, wherein the electric heating element has a protruding portion at an end thereof. Each L-shaped plate-shaped member, and each plate-shaped member is attached to the inner peripheral wall of the intake pipe where a relatively large amount of air-fuel mixture or liquid fuel flows through each of the projecting portions. An intake air heating device, characterized in that the base end side of each projecting portion of each plate member is arranged so as to face the inside of the intake pipe. 2. An electric heating body mounted on an inner peripheral wall side of an intake pipe connecting an intake passage of a carburetor and an intake port of a cylinder, and a heating body attached to the electric heating body and generating heat by energization from the outside. An intake air heating apparatus comprising: an electric heating element and a heating element for heating an air-fuel mixture or an unvaporized liquid fuel flowing from the vaporizer into the intake pipe, wherein the electric heating element is axially connected by press fitting or the like. Intake air heating, comprising at least two cylindrical members having different inner diameters, and one of the cylindrical members having the smaller inner diameter is disposed on the downstream side of the intake pipe. apparatus. 3. An electric heating body mounted on an inner peripheral wall side of an intake pipe connecting an intake passage of a carburetor and an intake port of a cylinder, and a heating body attached to the electric heating body and generating heat by energization from the outside. In an intake air heating device for heating an air-fuel mixture or an unvaporized liquid fuel flowing from the vaporizer to the intake pipe by the electric heating element and a heating element, the electric heating element is formed of a cylindrical member, and A projecting portion having a predetermined width is formed along the inner peripheral edge of one end of the cylindrical member in the axial direction, and the electric heating element is arranged with the projecting portion forming side facing the downstream side of the intake pipe. An intake air heating device comprising: 4. An electric heating element mounted on the inner peripheral wall side of an intake pipe connecting an intake passage of a carburetor and an intake port of a cylinder, and a heating element attached to the electric heating element and generating heat by energization from the outside. An intake air heating device comprising: an electric heating body and a heating element for heating a mixture of fuel or an unvaporized liquid fuel flowing from the vaporizer into the intake pipe, wherein the electric heating body includes a portion including a top of a cone. Of the hollow member having a shape cut in parallel to the bottom surface of the hollow member, and an opening portion of the hollow member having a larger inner diameter is arranged toward the downstream side of the intake pipe. Intake heating device. 5. The intake air heating device according to claim 1, wherein all or part of the electric heating element is formed as a mesh member made of metal or the like.