JPS5859352A - Sucked air heating device for internal-combustion engine - Google Patents

Abstract

PURPOSE:To simplify the fabrication of an electrode unit and to prevent the entry of rain water or dust into the unit by a method wherein a positive lead and a negative lead for energizing PTC elements inserted between an inner cylinder and an outer cylinder are molded integrally with the outer cylinder by using a resin material. CONSTITUTION:A hollow heat generating vessel 14 is provided inside a heat insulating plate 4 at the lower end of a primary carburetor. The vessel 14 comprises the inner cylinder made of a thin metallic material and the outer cylinder 16 made of a thin synthetic resin material. Further, the positive lead 144 and the negative lead 142 are formed integral with the outer cylinder. In this case, it is possible to mold these leads integrally with the outer cylinder since the latter is made of the synthetic resin material.

Description

[Detailed description of the invention] The present invention relates to an intake air heating device for an internal combustion engine.

Before the engine warm-up is completed when the engine temperature is low, the fuel supplied from the carburetor is not sufficiently vaporized, so a large amount of liquid fuel is supplied into the engine cylinder, and as a result, compared to after the engine warm-up is completed, a large amount of liquid fuel is supplied into the engine cylinder. There is a problem in that combustion becomes poor and stable operation of Isogata cannot be ensured. Therefore, normally, during warm-up operation, a richer mixture is supplied into the engine cylinder/cylinder to ensure stable engine operation. However, when such a rich mixture is supplied into the engine cylinder, harmful substances such as unburned hydrocarbons (HC) and carbon oxides (Co) in the exhaust gas are released.
This results in problems such as not only an increase in fuel consumption but also a worsening of fuel consumption. Therefore, if the liquid fuel supplied from the carburetor can be sufficiently vaporized during engine warm-up, stable engine operation can be ensured even if the air-fuel mixture supplied to the engine cylinders is diluted. By being able to use such a lean air-fuel mixture, harmful components in exhaust gas can be reduced and fuel consumption can be improved. Therefore, in order to promote the vaporization of liquid fuel during engine warm-up, the applicant first attached a hollow heating element container to, for example, an outlet part of the carburetor air horn, and connected this hollow heating element container to an inner cylinder. An electrode unit consisting of an outer cylinder and a positive characteristic thermostatic element (hereinafter referred to as a PTC element) inserted between the inner cylinder and the outer cylinder, and the PTC element is connected to an external power source;
Since this article concerns the modification of the structure of the electrode unit and the electrode unit for heating the inner cylinder of the hollow heating element container by heating the inner cylinder of the hollow heating element container, first of all, Fig. This will be briefly explained with reference to FIG.

In Fig. 1, 1 is the engine body, 2 is the intake manifold,
3 is a manifold collection part, 4 is a gasket 5, and 1
= A heat insulating board made of synthetic resin material is installed on the metal collecting part 3, and 6 indicates a vaporizer fixed on the heat insulating board 4 through a gasket door, and this vaporizer 6 is a primary side vaporizer. Vessel A
and a secondary side vaporizer B. The primary side carburetor A is equipped with a primary side air horn 8, a primary side main nozzle 9, a primary side slot, and a torque valve 10, and a secondary side carburetor B is equipped with a secondary side air horn 11, a secondary side main nozzle 9, a primary side slot, and a torque valve 10. Side main nozzle 12 and secondary side
, and a torque valve 13. As shown in Figure 1'
A hollow heating element container 14 is provided within the heat insulating plate 4 at the lower end of the primary carburetor A, aligned with the primary air horn 8 and extending centrally into the manifold collecting section 3. Figures 2 and 3
As shown in the figure, the hollow heating element container 14 has an inner cylinder 15 made of a thin metal material and an outer cylinder made of a thin synthetic resin material.

16. As shown in FIG.
has a middle part 16m having a uniform inner diameter, an upper end 16b having an inner diameter slightly larger than the middle part 16m, and a lower end 16 having a smaller inner diameter than the middle part 16m. A step portion 16d is formed at the intermediate portion 16m and the lower end portion 16@seki, which forms a tuna l annular shoulder portion 17 and a second annular shoulder portion 18 located below the first annular shoulder portion 17. An annular seven flange 20 having a rectangular cross section is integrally formed on the back surface of the intermediate portion 16m adjacent to the upper end portion 16b. Furthermore, the outer cylinder 16
A notch 21 extending from the upper end portion 16b into the seven flange 20 is formed on the top, and a bottom surface 22 of this notch 21 is a flat surface extending in the radial direction. Although this outer cylinder 16Fi is integrally molded from a synthetic resin material as described above, it can also be formed from a metal material.

On the other hand, the inner cylinder 15 is the second. As shown in Figure 3.5, the middle part (contact surface part) 15a has a regular octagonal cross section, and the cylindrical upper end part 1
5b, and a cylindrical lower end portion 15e. The cylindrical upper end portion 15b and the cylindrical lower end portion 15@ have the same inner diameter, and the entire thigh portion 15m bulges inward from the cylindrical upper end portion 15b and the cylindrical lower end portion l'5@. . A stepped 7-flange 23 extending outward is integrally formed at the tip of the cylindrical upper end 5tsb. The stepped 7-flange 23 has an inner 7-flange portion 23m with a cross section extending outward from the tip of the cylindrical upper end portion 15b, and an L-shaped cross-section 23m extending further outward from the tip of the inner 7-flange portion 23m. Outer flange portion 23b
It is composed of Furthermore, the tip of the cylindrical lower end X5C is integrally formed with seven flange 24 which extends outward and has a cross-sectional shape, and this seven flange z4 is connected to the outer cylinder 1 as shown in FIG.
6 and is caulked onto the lower end portion 16a of 6.

First, as shown in FIG. 2, between the inner cylinder 15 and the outer cylinder 16 is an insulating ring 2 made of a heat-resistant fluororesin such as ethylene or a heat-resistant material such as silicone.
5 is inserted and fitted into the inner 7 flange s23& of this insulating ring 25ti cylinder 15.

- On the other hand, as shown in FIGS. 2 and 3, the inner cylinder 15
An annular elastic electrode 29 made of KFi dull 7ite is inserted between the outer cylinder 16 and the outer cylinder 16. As shown in FIG. 6, this elastic electrode 29 has a cylindrical outer circumferential surface 30 and an inner circumferential surface 31 having a regular octahedral cross section, and is further separated by a slot 32 extending in the axial direction.

As can be seen from FIG. 3, this elastic electrode 29 is arranged between the inner tube 15 and the outer tube so that each flat surface constituting the inner peripheral surface 310 of the octahedron faces each flat surface constituting the octahedron of the inner tube 15. 16
inserted into the seki. Also, elastic electric li! The length of i29 in the annular direction is shorter than the length of the inner cylinder intermediate portion ISa, and the elastic electrode 29 is disposed within the region of the inner cylinder intermediate portion ISm. - PTCi elements 33 are inserted into each of the flat outer peripheral surface portions of the inner cylinder intermediate portion 151 and the elastic electrode 1i29, and furthermore, an insulating member 34 is inserted so as to surround the outer peripheral wall of each of these r°C elements 33. . As shown in FIG. 7, the insulating member 34 is made of a strip of asbestos (the strip is shown rolled into a ring shape in FIG. 7), and has eight openings 3 at equal intervals.
5 is formed. On the other hand, each PTC element 33 is formed into a flat plate with a rectangular outline as shown in Figure *8, and each opening 35 of the insulating member 34 has an outline approximately equal to the outline of the PTC element 33. Further, each opening 35 is separated by each equally spaced rib portion 36. Insulating member 34
The flat surfaces constituting the regular octagon are respectively arranged on the flat outer peripheral surfaces constituting the regular octagon of the inner cylinder 15, and the insulating member 34
A PTC element 33 is inserted into each of the openings 35 .

A ta unit 39 extending radially outward is attached to the upper end of the hollow heating element container 14 . This electrode Yu=,)3
As shown in Figure 9tiM9, a metal U-shaped cross-sectional ring 40, a strip-shaped negative lead @ 42 covered by an insulating tube 41, and a strip-shaped glass side lead covered by an insulating tube 43. @44 and a pair of terminals 45
．． A connector 47 with 46 is provided. The insulating chips 41 and 43 are stacked on top of each other, and a retainer 48 made of shim material is inserted over the outer periphery of the stacked nine insulating chips 41 and 43.

JI! As shown in FIG. 9, the inner end 49 of the negative lead wire 42 is bent upward at a right angle, and the bent inner end 4
9 is welded into the U-shaped cross-section of the ring 40. Nine!
The outer end of the inusu lead wire 42 is connected to the terminal 4 of the connector 47.
Connected to 5. On the other hand, the inner end portion 50 of the positive side lead wire 440 is bent downward on the opposite side from the bent inner end IB49 of the negative side lead wire 42.
The outer end of 44 is connected to the terminal 46 of the connector 47.
As shown in FIG. 2, the U-shaped cross section of the ring 40 is fitted onto the upper end 16b of the outer tube 16, and the outer 7 flange portions 23b of the inner tube 15 are crimped onto the puffer 40. on the other hand,
The bent inner end l550 of the positive lead wire 44 is located at the middle l550 of the outer cylinder.
It is inserted between B16m and elastic wire 29. - As shown in FIG. 1, the heat insulating plate 4 is formed with a large diameter hole 51 and a small diameter hole 52 which are connected to each other, and the hollow heating element container 14 is disposed within the large diameter hole 51. In the front, the small diameter hole 52 is aligned with the secondary air horn 11. Grooves 53 and 54 having an L-shaped cross section are formed along the entire length of the lower part of the inner peripheral wall surface of the heat insulating plate 4 that defines the large diameter hole 51 and the small diameter hole 52,
Nine flanges 20 are integrally formed on the outer circumferential wall surface of the outer cylinder 16 and fitted into the grooves 53 of the large diameter holes 51 . Furthermore, a dovetail groove 55 is formed on the lower wall surface of the heat insulating plate 4, and this dovetail groove 55
The inner part 48b of one retainer 48 is fitted inside.

Next, the operation of the above-described intake air heating device will be explained as follows.

The minus side lead pH42 is grounded, and the glass side lead wire 44 is connected to the temperature detection switch 110. It is connected to a power source 113 via a neutral point voltage detection switch 1.11 and an ignition switch 112.

The temperature detection switch 110 indicates that the engine cooling water temperature is, for example, 6-0.
It is on when the engine cooling water temperature is below 60°C, and turns off when the engine cooling water temperature is above 60°C. On the other hand, the neutral point voltage detection switch 111 is in an off state when the neutral point voltage of the engine-driven alternator is below a predetermined level, and is in an on state when this neutral point voltage exceeds a predetermined level.

- It is necessary to prevent the p'rc element 33 from starting supplying current to the q PTC element 33 when the starter motor is being driven to start the engine, when a large current flows when starting the current supply. For this purpose, a neutral point voltage detection switch 111 is provided. That is, when the engine is rotated by the starter motor, the neutral point voltage is low;
When the engine starts self-driving operation, the neutral point voltage becomes high and the neutral point voltage detection switch ill turns on, and the PTC
Supply of current to the element 33 is started. In this way PTC
When supply of current to element 3'3 starts, PTC element 33
As soon as the dust spreads, the temperature rises, and as a result, the inner cylinder 15 also cools! The temperature rises to .

On the other hand, when the engine starts, most of the liquid fuel is supplied from the primary side, vaporization -A, and most of the liquid fuel is supplied from the primary side, vaporization -A.
Then, this liquid fuel in-house cylinder 1
It descends along the inner wall surface of 5.

The outer cylinder 16 is made of a heat insulating material, and the outer cylinder 15 is supported by the heat insulating plate 4.

Therefore, only a small amount of the heat generated from the PTC element 33 escapes to the intake manifold 2 and the carburetor 6, and most of the heat generated from the I'TC element 33 escapes to the inner cylinder 1.
Used to heat 5. Furthermore, the inner wall surface of the cylinder 15 is covered with liquid fuel, and therefore most of the heat emitted from the PTC element 33 is used to vaporize the liquid fuel. In addition, since the inner cylinder middle part 15& is bulged inward from the inner cylinder upper end part 1511, fuel droplets floating in the air-fuel mixture will adhere to the inner cylinder middle part 1saK and will not be able to penetrate the inner cylinder, thus preventing the vaporization of the fuel. This can be further promoted.

On the other hand, if the engine cooling water temperature rises above 60 degrees Celsius shortly after starting the aircraft, it is too hot! When the detection switch 110 is turned off, the supply of current to the ninth K PTC element 33 is stopped.

As is well known, the thermal conductivity of graphite is directional, and the thermal conductivity in the radial direction is lower than that in the circumferential direction. Therefore, graphite has difficulty in conducting heat in its radial direction, and the elastic electrode 29 has a heat insulating effect. As mentioned above, the outer cylinder 16 is made of a heat insulating material, and since the elastic electrode 29 has a heat insulating effect, most of the heat generated from the PTC element 33 can be used to heat the inner cylinder 15. . On the other hand, Graphai I
nThe inner cylinder 15 is relatively easy to conduct heat in the circumferential direction.
can be heated evenly.

However, in the above-mentioned intake air heating device, the anode lead is 1l.
144 and the negative electrode lead wire 42 are assembled into the retainer 48, which is then assembled into the heating element container, which not only has a double-wire structure and is extremely troublesome to assemble, but also makes it difficult to assemble the wire from the lead wire outlet. Undesirable problems have arisen in that fuel leaks outside or rainwater, dust, etc. conversely intrude into the interior.

In order to solve this problem, the present invention provides a lead (conductor) for the outer cylinder.
By integrally molding them with resin mold, we are able to reduce the number of parts, reduce the assembly process, and improve airtightness. The aim is to improve reliability and reduce manufacturing costs.

In order to achieve this purpose, according to the present invention, as shown in FIG.
Both parts are integrally molded together with the outer cylinder 16. That is, the outer cylinder 16
Since these are molded from resin, it is sufficient to integrally cast these leads into an insert mold.

As shown in FIG. 12, the electrode lead 144 is bent downward and is formed from a highly electrically conductive band plate made of copper, aluminum, etc. and has a large circular end 150. On the other hand, the negative electrode lead -Y142 is the same as the anode lead 144. It is made of material and has a ring-shaped end 11$140. These leads 142.144
The ends of are connected to terminals 45, 46 shown in FIG. Note that, as shown in FIG. 14, the insulating member 34' is formed by integrally molding the insulating member 34 and the insulating ring 25 shown in FIG. 2. In addition, in Fig. 2 and Fig. 814, for example, the inner cylinder 15
Although the shape of the lower end of the outer cylinder 16 and the like are slightly different, the one shown in FIG. A seal member 80 is preferably inserted between the heat insulating plate 4 to improve airtightness.

As described above, according to the present invention, by integrally insert molding the anode lead and the negative electrode lead with the outer cylinder, it is possible to reduce the assembly process of the electrodes and the number of parts, and furthermore, the assembly process of the electrodes and the number of parts can be reduced. Intrusion of dust and leakage of fuel from the heating element container can be prevented.

[Brief explanation of the drawing]

Figure 1 is a side sectional view of the engine intake system according to the applicant's earlier application, Figure 2 is a side sectional view of the heating element container taken along line H-1 in Figure 3, and Figure 3 is the Figure 4 is a perspective view of the outer cylinder, Figure 5 is a perspective view of the inner cylinder, Figure 6 is a perspective view of the elastic electrode, and Figure 7 is the insertion. FIG. 8 is a perspective view of the pTC element,
FIG. 9 is a side cross-sectional view of the electrodes, FIG. 10 is a cross-sectional side view showing an outer cylinder integrally molded with the current-carrying electrode according to the present invention, and FIG. 11 is all! 10 is a plan view, FIG. 12 is a perspective view of an anode lead, FIG. 13 is a perspective view of a negative electrode lead, FIG. 14 is a cross-sectional side view of a heating element container incorporating the outer cylinder shown in FIG. 10, and FIG. The figure is a view taken in the direction of the Xv line in FIG. 14. 2... Intake manifold, 4... Heat resistant plate, 6... Carburizer, 14... Heating element container, 15... Inner cylinder, 16...
...Outer cylinder, 20.23.24...7 lunge, 25...
・Insulation resig, 29...Elastic electrode, 33...PTC
Element, 34... Insulating member, 39... Electrode unit,
40...Ring, 142...Negative electrode lead, 144...
...Anode lead. Patent Applicant Toyota Motor Corporation Patent Application Agent Akira Aoki Patent Attorney Kazuyuki Nishidate Patent Attorney Masayuki Yoshida Akira Yamaguchi Figure 4, 5th 4r1, 6th Figure 9.

Claims (1)

[Claims] A hollow heating element container constituted by an inner cylinder, an outer cylinder, and a PTC element inserted between these inner and outer cylinders is provided in the intake passage leading from the fuel supply device to the engine cylinder, and is communicated with the P'rC element. An intake air heating device for an internal combustion engine that heats an inner cylinder by heating the inner cylinder, characterized in that the outer cylinder is integrally molded with an anode and a negative electrode lead for passing through the FiPTC element. intake air heating device.