JPH1144256A - Heating device for carburetor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform the generation of heat of a PTC heater with high efficiency to heat the carburetor of an engine for an automobile. SOLUTION: A recessed part 8 is formed in the coupling surface 7b of an insulation heat insulator 7 coupled to the conductive housing of a carburetor, an electrode plate 9 is formed on the bottom of a recessed part 8, and a disc- form PTC heater 12 adhered to a conductive fixed plate 11 through a conductive spring 10 is forced into a pressure contact. In a so formed heat generating device, the fixed plate 11 is formed in a hollow state such that a contact area between the spring 10 and the fixed plate 11 is decreased. Since capacity of heat of the fixed plate 11 is decreased and further thermal conduction to the spring 10 is decreased, the generated heat of the PTC heater 12 heats mainly the housing. Further, since the fixed plate 11 is formed in a hollow state, reduction of the weight of an automobile is promoted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION A carburetor mounted on an automobile engine vaporizes fuel. At that time, the surroundings are cooled by heat of vaporization, and there is a possibility that an icing phenomenon may occur particularly during starting or in a cold season. It is known to improve the combustion conditions by heating the corresponding location. The present invention relates to a heating device for a vaporizer using an electric heater.

[0002]

2. Description of the Related Art Conventionally, a carburetor is mounted in an intake passage of an automobile engine, and a heat insulator is connected to a downstream end of the carburetor passage so that an icing phenomenon is prevented by a heater in the heat insulator. ing. The heater used for this is made of a barium titanate-based semiconductor having a positive temperature coefficient. Both surfaces are covered with a nickel plating layer, and a silver layer is formed thereon to provide an electrode surface (hereinafter, a PTC heater). ). After the temperature of the PTC heater rises to some extent, the resistance becomes high in proportion to the temperature, so that it becomes difficult for a current to flow and the heating can be controlled.

A PTC heater is installed in a recess on the heat insulator side of a connection surface between a conductive housing of a vaporizer and an insulating heat insulator so as to be in close contact with the housing, and heats the vaporizer. I have. As an example, a heating device for a vaporizer will be described with reference to FIG.
An intake passage 2a is formed in the conductive housing 2 of the carburetor 1, and a slow port 3 and an idle port 4 for supplying fuel are provided in a line from the upstream side facing the intake passage 2a, and inside the intake passage 2a. A throttle valve 5 is provided. An end surface of a heat insulator 7 made of a heat-resistant insulating resin of the heating device 6 is connected to a downstream side surface of the vaporizer 1 so as to align the intake passage 7a.

As shown in FIG. 9, a concave portion 8 is formed on a connecting surface 7b of a heat insulator 7, and an electrode plate 9 is provided on a bottom surface of the concave portion. The recess 8 has a conductive spring 10, a conductive fixing plate 11, a PTC
The heater 12 is housed (see FIG. 10), and the PTC heater 12 is pressed against the housing 2 by the urging force of the spring 10.

As shown in FIG. 10, an engaging portion 13 of a vertical groove which is open upward is provided at two places on the inner peripheral surface of the concave portion 8 of the heat insulator 7, and a circumferential direction is formed on the wall surface of the engaging portion 13. A notch 14 is formed at the bottom. In addition, the conductive spring 10 cuts and bends the peripheral edge of the substantially circular plate in the circumferential direction, and
And the foot 10b, and elasticity is secured by the foot 10b. The fixing plate 11 is formed in a columnar shape, and a projection 15 to be inserted into the engaging portion 13 is provided symmetrically on the outer peripheral surface. A disc-shaped PTC heater 12 is provided on the upper surface of the fixing plate 11 for heat conduction and electric conduction. Glued with good adhesive 16.

As shown in FIG. 9, when the PTC heater 12 is mounted in the recess 8 of the heat insulator 7, the projection 15 of the fixing plate 11 adhered to the PTC heater 12 comes into contact with the ceiling of the notch 14 and is supported. The PTC heater 12 is slightly protruded from the connection surface 7b. Therefore, the PTC heater 12 does not come off from the opening of the concave portion when not connected to the vaporizer 1. Then, when the heat insulator 7 is mounted on the housing 2 of the vaporizer 1, the PTC heater 12 is pressed against the lower surface of the housing 2 and is brought into a pressure contact state.
When removing the heat insulator 7 from the housing 2, the PTC heater 12 is adhered to the fixing plate 11 to prevent the heat insulator 7 from falling off.

[0007]

By the way, the heating device 6
Is the electrode plate 9, the spring 10, the fixed plate 11,
An electric current flows in the order of the PTC heater 12 and the housing 2,
The C heater 12 generates heat. Since the entire surface of the PTC heater 12 is pressed against the housing 2 by the urging force of the spring 10, the heat conduction is good and the housing 2 is heated. However, the entire surface of the PTC heater 12 is also fixed to the fixed plate 11 and heat conduction is good, so that not only the vaporizer 1 but also the fixed plate 11, the spring 10 and the like are heated, that is, the fixed plate 11, the spring 10 and the like. , And the efficiency of heating the vaporizer 1 is reduced.

An object of the present invention is to provide a vaporizer heating device in which the heat generated by a PTC heater works efficiently.

[0009]

In order to achieve the above object, according to the present invention, a concave portion is formed in a connecting surface of a heat insulator connected to a downstream end of a passage of a vaporizer. A conductive plate having a receiving seat is disposed on the upper surface, and a fixing plate having a disc-shaped PTC heater fixed on the upper surface thereof with an adhesive is placed on the receiving seat of the spring, and the disc-shaped PTC heater is connected to the connecting surface. A heating device for the carburetor, which is slightly protruded from the spring, and is locked against the upward biasing force of the spring, wherein the fixing plate has a cylindrical shape having a ceiling surface, and a lower peripheral edge is a receiving seat of the spring. Abutting on the contact.

According to a second aspect of the present invention, a concave portion is formed in a connecting surface of a heat insulator connected to a downstream end of a passage of a vaporizer, a conductive spring having a receiving seat is disposed in the concave portion, and a disk is provided on an upper surface. A fixing plate on which the PTC heater is fixed with an adhesive is placed on a receiving seat of the spring, and at a position where the disc-shaped PTC heater slightly protrudes from the connection surface, the spring resists the upward urging force of the spring. A heating device for a locked carburetor, wherein the fixing plate is formed in a cylindrical shape.

According to a third aspect of the present invention, a concave portion is formed in a connection surface of a heat insulator connected to a downstream end of a passage of a vaporizer, a conductive spring having a receiving seat is disposed in the concave portion, and a disk is provided on an upper surface. A fixing plate on which the PTC heater is fixed with an adhesive is placed on a receiving seat of the spring, and at a position where the disc-shaped PTC heater slightly protrudes from the connection surface, the spring resists the upward urging force of the spring. A heating device for a locked vaporizer, wherein a part of a connection surface between the fixed plate and the PTC heater, or a case where the fixed plate and the PTC heater are partly connected to each other. The present invention is characterized in that a conductive adhesive is applied to the entire bonding surface or a part of the bonding surface.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings. The position of the recess provided in the heat insulator is slightly different depending on the direction of the intake passage of the carburetor and the heat insulator. And at a position below the idle port. Heating device 6 shown in FIGS. 1 and 2
The insulating heat insulator 7 is connected to the carburetor by a connection surface (upper surface) 7b, and an intake passage 7a is formed continuously with the intake passage of the conductive housing. A cylindrical recess 8 is provided on the connecting surface 7b near the intake passage 7a so as to face the conductive housing of the carburetor.

The recess 8 formed in the heat insulator 7
An electrode plate 9 for supplying a current from a power supply to the PTC heater 12 is provided on the bottom surface, and a conductive spring 10 including a disc-shaped receiving seat 10a and an elastic foot portion 10b is mounted thereon. You. The opening edge of the concave portion 8 has an engaging portion 13 of a pair of vertical grooves.
Are formed symmetrically in the radial direction, and the engaging portion 13 is formed with a cutout portion 14 in the circumferential direction. A conductive fixing plate 11 is placed on the receiving seat 10a of the spring 10, and the fixing plate 11 is formed in a cylindrical shape having a ceiling surface, and the lower peripheral edge thereof comes into contact with the receiving seat 10a of the spring 10. Also, fixed plate 11
Of the heat insulator 7, the protrusion 15 is large enough to be inserted into the engagement portion 13 of the recess 8 and to enter the notch 14.
Are formed symmetrically in the radial direction. In addition, protrusion
The thickness of 15 is smaller than the height of the notch 14.

A disc-shaped PTC heater bonded to the upper surface of the fixing plate 11 with a silver adhesive 16 having good heat and electric conductivity.
There are twelve. The fixing plate 11 is made of a metal such as aluminum, iron, stainless steel, copper, brass, or an alloy metal containing two or more of these, or a carbon material. The silver adhesive 16 is made of silver-polyimide. Resin, silver-epoxy resin, silver-silicon resin, silver-glass and the like are used.

As shown in FIG. 2, when the PTC heater 12 is mounted in the recess 8, the protrusion 15 of the fixing plate 11 is
Of the fixed plate 11 and the bonded PTC heater
Rotate 12 to insert projection 15 into notch 14. When the downward pressing force of the PTC heater 12 is released from this state,
The projection 15 is locked at a position above the notch 14 by the urging force of the spring 10, and the PTC heater 12 slightly protrudes from the connection surface 7 b of the heat insulator 7.

A gap is formed below the projection 15 which is locked in the notch 14, and the height of the PTC heater 12 protruding is smaller than the gap, so that the PTC heater 12 has play in the vertical direction. Be engaged. This heat insulator 7
When the carburetor and the carburetor are combined, the PTC heater 12 is pushed into the conductive housing of the carburetor to the same height as the connecting surface 7b of the heat insulator 7, and is pressed against the conductive housing with a predetermined load by the urging force of the conductive spring 10. You.

Thus, the electrode plate 9, the conductive spring
10, fixed plate 11, conductive adhesive 16, PTC heater 1
2. The conductive housings are sequentially coupled to form a closed circuit, and can supply current to the PTC heater 12. P
When a current is supplied to the TC heater 12, the PTC heater 12 heats the conductive housing of the vaporizer. However, the structure of the present invention has a small heat capacity because the shape of the fixed plate 11 is a hollow body, and the conventional cylinder has a small heat capacity. The heat conducted to the fixing plate 11 is reduced as compared with the shape, and the conductive housing of the vaporizer can be efficiently heated. As a result, icing that occurs near the slow port of the vaporizer can be prevented. As for the temperature rise characteristics near the slow port, as shown in FIG. 7, the heat transfer of the present invention is better in the case (a) than in the conventional case (b), and the temperature rise speed of the vaporizer can be increased. The ambient temperature under the experimental conditions was −9 ° C., the initial temperature of the vaporizer was −5 ° C., and the applied voltage was 13.5V.

Next, the fixing plate 11 having a hollow cylindrical shape will be described with reference to FIGS. The shape of the receiving seat 10a of the conductive spring 10 has a circular shape with three sides cut out, and the lower end of the fixed plate 11 to be in contact with is annular. Therefore, when the PTC heater 12 is mounted in the concave portion 8, when the fixing plate 11 is placed on the receiving seat 10a and the projection 15 of the fixing plate 11 is still at a position higher than the coupling surface 7b, the shaft is rotated to form the projection. 15 can be smoothly fitted to the engaging portion 13. When the fixing plate 11 is placed on the receiving seat 10a when the fixing plate 11 is lowered by aligning the projection 15 with the engaging portion 13, the positioning of the fixing plate 11 with respect to the receiving seat 10a is determined. It is not necessary to make the whole circle.
The upper end of the fixing plate 11 has an annular shape, and the conductive adhesive 16 is applied on the annular shape, and the PTC heater 12 is coupled to the upper surface thereof. Also, conductive adhesive
The 16 coated surfaces may be intermittent. In the heating device 6 configured as described above, since the fixed plate 11 is cylindrical, the contact surface is narrow and heat conduction is reduced, and the heating efficiency for the vaporizer is:
It is even better than the previous one (see FIG. 7). However,
In applying the conductive adhesive 16 to the connection surface between the fixing plate 11 and the PTC heater 12, the above-described one has a flat application surface, is easy to apply, and has excellent workability.

Next, the surface to which the conductive adhesive 16 is applied will be described with reference to FIGS. Column-shaped fixing plate 11
The PTC heater 12 is fixed on the upper surface by the conductive adhesive 16 applied to the fixing plate 11.
Is applied in a band along the circumference of the upper surface of the. This allows
The shape of the application surface was structurally symmetric, the application area was reduced, and the joint area between the fixed plate 11 and the PTC heater 12 was reduced. Therefore, the heat conducted to the fixed plate 11 is reduced, and the heating efficiency for the vaporizer is improved. Further, even if the application surface is formed in an X-shape or an S-shape, it is sufficient that the stress is substantially equal in structure, and the application surface can also be used for the fixed plate 11 having a free ceiling on the application surface.

[0020]

According to the present invention, the heat capacity of the fixed plate is small, so that the heat conduction to the fixed plate is small and the efficiency of heat conduction to the vaporizer is good.
Further, by reducing the bonding area between the PTC heater and the fixing plate, the heat conduction to the fixing plate is small and the efficiency of the heat conduction to the vaporizer is high. Further, by making the fixing plate cylindrical, the bonding surface is also limited, and the workability is good, and the hollowing of the fixing plate can promote the reduction in weight of the automobile.

[Brief description of the drawings]

FIG. 1 is a development view of a heating device for a vaporizer according to the present invention.

FIG. 2 is a sectional view of the heating device shown in FIG.

FIG. 3 is a sectional view showing a modification of the heating device shown in FIG.

FIG. 4 is a development view of a main part of the heating device shown in FIG. 3;

FIG. 5 is a sectional view showing another modification of the heating device shown in FIG. 1;

FIG. 6 is an expanded view of a main part of the heating device shown in FIG.

FIG. 7 is a graph showing the effect of the heating device of the vaporizer according to the present invention.

FIG. 8 is a sectional view of a conventional vaporizer and heating device.

9 is a cross-sectional view of the heating device shown in FIG.

FIG. 10 is a development view of the heating device shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vaporizer 6 Heating device 7 Heat insulator 7b Connecting surface 8 Depression 10 Spring 10a Receiving seat 11 Fixing plate 12 PTC heater 16 Conductive adhesive

Claims (3)

[Claims] 1. A concave portion is formed in a connecting surface of a heat insulator connected to a downstream end of a passage of a vaporizer, a conductive spring having a receiving seat is disposed in the concave portion, and a disc-shaped PTC heater is provided on an upper surface with an adhesive. A carburetor in which the fixed plate fixed by the above is mounted on the receiving seat of the spring and the disc-shaped PTC heater is locked at a position where the disc-shaped PTC heater slightly protrudes from the connection surface against the upward urging force of the spring. The heating device according to any one of claims 1 to 3, wherein the fixing plate has a cylindrical shape having a ceiling surface, and a lower peripheral edge thereof is in contact with a receiving seat of the spring. 2. A concave portion is formed in a connecting surface of a heat insulator connected to a downstream end of a passage of a carburetor, a conductive spring having a receiving seat is disposed in the concave portion, and a disc-shaped PTC heater is provided on an upper surface with an adhesive. A carburetor in which the fixed plate fixed by the above is mounted on the receiving seat of the spring and the disc-shaped PTC heater is locked at a position where the disc-shaped PTC heater slightly protrudes from the connection surface against the upward urging force of the spring. The heating device for a vaporizer, wherein the fixing plate is formed in a cylindrical shape. 3. A concave portion is formed in a connecting surface of a heat insulator connected to a downstream end of a passage of a carburetor, a conductive spring having a receiving seat is arranged in the concave portion, and a disc-shaped PTC heater is provided on an upper surface with an adhesive. A carburetor in which the fixed plate fixed by the above is mounted on the receiving seat of the spring and the disc-shaped PTC heater is locked at a position where the disc-shaped PTC heater slightly protrudes from the connection surface against the upward urging force of the spring. The heating device according to claim 1, wherein a part of a coupling surface between the fixed plate and the PTC heater, or a whole coupling surface or a part when the fixed plate and the PTC heater are partially coupled to each other. A heating device for a vaporizer, wherein a conductive adhesive is applied to a bonding surface.