JPH0216053Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to an intake air heating device that uses an electric heater to heat the intake air supplied to the thermal combustion chamber of an engine. the heater is adapted to be attached to an insulator mounted between the carburetor and the intake manifold;
This invention relates to an engine intake air heating device.

(Prior Art) In the case of an automobile engine used in a cold region, the engine is cold when it is started and the intake air temperature is low, so that fuel is difficult to vaporize. Therefore, in such an engine, when starting, the intake air, fuel, or air-fuel mixture supplied to the combustion chamber is heated to promote vaporization and mixing of the fuel, and to improve startability. Efforts are being made to suppress the generation of harmful components and reduce fuel consumption.

Various types of such intake air heating devices have been considered, one of which is a PTC system as shown in Japanese Patent Application Laid-Open No. 53-59130.
There is an electric heating device that uses a heater (an element with positive temperature characteristics). This PTC heater is made of a ceramic semiconductor that generates heat in a relatively short time when voltage is applied, and self-temperature-controls when it reaches a set temperature. It is considered to be the best as a heating heater. The PTC heater is generally attached to an insulator that provides insulation between the carburetor and the intake manifold, and by heating the air-fuel mixture that passes through it, fuel vaporization is performed efficiently. It's like that.

When attaching a PTC heater to an insulator in this way, it is necessary to supply power to the PTC heater from an external power source through the insulator. Therefore, in the above-mentioned publication, the insulator is composed of several insulating plates stacked on top of each other, and the terminal of the conductor that transmits electricity to the PTC heater is protruded from the outside through between the insulating plates. I try to let them do it.

(Problem that the invention attempts to solve) However, when the insulator is constructed from several insulating plates, etc., the number of parts not only increases, but also complicates parts management. , there is a problem in that the assembly work is also complicated.

Incidentally, in recent years, such PTC heaters have appeared in which a ceramic element is housed in a metal enclosure and a voltage is applied to the element through the enclosure. If such a PTC heater is used, a metal plate-shaped lead wire connected to an external power source is buried inside the insulator, and the enclosure of the PTC heater is connected to the lead wire. It becomes possible to fix the PTC heater to the insulator and supply power to it.

When joining a PTC heater enclosure to a metal plate lead wire as described above, caulking using rivets is generally used from the viewpoint of heat resistance and workability. However, in order to make such a rivet connection, it must be possible to insert a tool on both sides of the rivet. Therefore, it is necessary to provide a working hole at the joint between the lead wire and the enclosure of the PTC heater, which reaches from the outer surface of the insulator to the joint.

On the other hand, an insulator installed between the carburetor and the intake manifold is provided with an intake passage passing through the insulator so that intake air is guided from the carburetor to the intake manifold through the insulator. In order to seal the intake passage from outside air, sealing members are installed between the insulator, the carburetor, and the intake manifold, respectively. Normally, a gasket is used as a sealing member between the insulator and the intake manifold, but an O-ring is used as a sealing member between the insulator and the carburetor to absorb vibrations transmitted to the carburetor. It is used. Therefore, a small gap is formed between the carburetor and the insulator.

Such an O-ring is installed as close as possible to the intake passage. If the O-ring is located away from the intake passage, fuel will accumulate in the gap between the carburetor and insulator due to capillary action, which will affect the concentration of the air-fuel mixture supplied to the engine's combustion chamber. Put it away. For this reason, the work hole for riveting the lead wire and the PTC heater enclosure as described above is inevitably exposed to O2 on the carburetor side of the insulator.
It will be located outward from the ring.

However, if the joining hole is located outside the O-ring in this way, the outside air that has flowed into the gap between the carburetor and the insulator will flow into the intake passage through the hole and the gap between the rivet joint. . In addition, when the engine is stopped after high-load operation, the engine becomes hot and the intake system is filled with evaporated fuel, which leaks to the outside through gaps in rivet joints and work holes. . Furthermore, if water enters the gap between the carburetor and the insulator, it will adhere to the rivet joints and cause damage.
It can also cause corrosion of that part.

The present invention was developed in view of these problems, and its purpose is to facilitate the work of connecting the lead wire inside the insulator to an electric heater such as a PTC heater by providing a work hole in the insulator. The purpose is to make it easy to carry out the work, but also to prevent outside air or moisture from flowing in or fuel from leaking through the work hole.

(Means for solving the problem) In order to achieve this purpose, in the present invention, the insulator is provided with a joining hole that reaches the joint between the lead wire and the electric heater, and after the joining operation, the The hole is filled with sealing resin. The resin may be filled only from the side of the vaporizer.

(Function) In this way, by providing the joining work hole in the insulator, both sides of the joint between the lead wire and the electric heater are open, so work such as riveting can be easily performed. It becomes like this. After the joining operation is completed, the working hole is closed with a sealing resin, so that air or fuel is prevented from flowing through the working hole. Furthermore, since moisture will no longer adhere to the joints, corrosion due to this will be reliably prevented. Therefore, the gap between the carburetor and the insulator only needs to be sealed with an O-ring as in the past, and there is no need for a special seal.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

The figure shows an embodiment of the intake air heating device according to the present invention, and FIG.
The figures are an exploded perspective view and a bottom view of the intake air heating device, respectively. Moreover, FIG. 4 is a schematic cutaway side view of the main part of the engine equipped with the intake air heating device.

As is clear from FIG. 4, an intake system 5 consisting of an air cleaner 2, a carburetor 3, and an intake manifold 4 is passed through the combustion chamber 1a of the engine body 1.
Air-fuel mixture is being supplied. vaporizer 3
is a two-barrel type, and includes a primary passage 3a that opens even under low load and a secondary passage 3b that opens only under high load.

Since the engine body 1 becomes hot during engine operation, the carburetor 3 and the intake manifold 4 are installed in order to prevent the heat from being transferred to the carburetor 3 and the fuel in the fuel passage becoming high temperature. A flat insulator 6 is provided between the two. This insulator 6 is molded from a hard resin such as Bakelite or phenol resin that has heat and electrical insulation properties, and as shown in FIGS. Vessel 3
Two intake passages 6a and 6b are provided which communicate the intake manifold 4 with the intake manifold 4. A PTC heater 7 is attached to one of the intake passages 6a communicating with the primary passage 3a of the carburetor 3.

This PTC heater 7 has a main body 8 of a honeycomb structure having a large number of square cross-sectional passages made of ceramic whose resistivity has a positive temperature characteristic, and a voltage is applied to the partition wall between each passage from both sides. Its outer periphery is covered with a metal enclosure 9. This enclosure 9 is provided with three legs 9a, 9b, and 9c. Further, the PTC heater 7 is provided with another leg portion 10 insulated from the enclosure 9. As shown in FIG. 1, the enclosure 9 is electrically connected to one side of the honeycomb-shaped partition wall of the PTC heater body 8, and the other leg part 10 is electrically connected to the other side of the partition wall. connected.

As is clear from FIGS. 1 and 3, a recess 11 into which the PTC heater 7 is inserted is provided on the lower surface of the insulator 6 on the intake passage 6a side, that is, on the surface on the intake manifold 4 side. As shown in FIG. 3, three metal strip-shaped lead wires 12, 13, and 14 are buried inside the insulator 6. 2 of these
The outer ends of the lead wires 12 and 13 protrude from one side of the insulator 6, and the terminal 1
5 and 16. A pair of conductive wires 17, 17 are connected to the terminals 15, 16.
are connected by spot welding or the like, and these conductors 17, 17 are connected to an external power source such as an on-vehicle battery through a connector 18. The connection portions between the terminals 15 and 16 and the conductive wires 17 and 17 are covered with a waterproof cover 19.

The inner ends of the lead wires 12 and 13 are respectively
It is exposed in the recess 11 of the insulator 6 at positions corresponding to the legs 10 and 9a of the PTC heater 7. Further, both ends of the other lead wires 14 are connected to the legs 9b and 9 of the PTC heater 7, respectively.
It is exposed within the recess 11 at a position corresponding to c. In this way, when the PTC heater 7 is inserted into the recess 11, each lead wire 12, 1
3, 14 and each leg 10, 9a of the PTC heater 7,
9b and 9c are electrically connected to each other.

As is clear from FIGS. 1 and 2, the upper surface of the insulator 6, that is, the surface on the side of the carburetor 3, has four working holes 20 at positions corresponding to the respective ends of the lead wires 12, 13, and 14. 20,... are provided. As shown in FIG. 1, this working hole 20 is connected to a lead wire 1
It is supposed to reach up to 2, 13, and 14.
Therefore, each end of the lead wires 12, 13, 14 is open to both the upper and lower sides of the insulator 6.

When attaching the PTC heater 7 to the insulator 6, first insert it from the bottom side of the insulator 6 so that it is accommodated in the recess 11. Each leg 10 of the PTC heater 7,
9a, 9b, and 9c are arranged to overlap each end of the lead wires 12, 13, and 14, respectively. At this time, if the shapes of the legs 10, 9a, 9b, and 9c are made different from each other as shown in FIG. 3, there is no possibility of incorrect mounting positions. In this state, insert the rivets 21, 21, ... from the recess 11 side, and connect the legs 10, 9a, 9b,
The lead wires 9c are inserted through the joints of the lead wires 12, 13, and 14, respectively. Next, a tool is inserted into the working hole 20 and the end of the rivet 21 is caulked.
Thereby, the PTC heater 7 is fixed to the insulator 6, and the PTC heater 7 and each lead wire 12, 13, 14 are electrically connected.

In this way, each leg 10 of the PTC heater 7,
9a, 9b, 9c and each lead wire 12, 13, 14
After joining, the working holes 20, 20,...
Fill with epoxy sealing resin 22, 22, . This resin 22 hardens while sealing the working hole 20.

The insulator 6 to which the PTC heater 7 is attached in this way, as shown in FIG.
It is placed on the intake manifold 4 via a gasket 23. Furthermore, on the insulator 6,
The carburetor 3 is attached with the O-ring 24 in between. This O-ring 24 surrounds the openings of the intake passages 6a and 6b of the insulator 6,
placed near the opening. And vaporizer 3
By tightening the assembly bolts between the intake manifold 4 and the intake manifold 4, the insulator 6 is clamped and fixed between them. Thereafter, the terminals 15 and 16 of the insulator 6 and the battery are connected by conductive wires 17 and 17.

When starting the engine at a low temperature, air-fuel mixture is supplied from the primary passage 3a of the carburetor 3. This air-fuel mixture is guided to the intake manifold 4 through the intake passage 6a of the insulator 6. At this time, at the same time,
Electricity is supplied from the battery through the conductive wires 17, 17. As a result, electric power is supplied to one side of the honeycomb-shaped partition wall constituting the PTC heater main body 8 through the terminal 15, the lead wire 12, and the leg part 10 of the PTC heater 7, and the other side of the partition wall is supplied with electric power. , terminal 16, lead wire 13,
Legs 9a of PTC heater 7 and enclosure 9
Power is supplied through the Therefore, voltage is applied to the partition wall from both sides, and the partition wall generates heat. In this way, the air-fuel mixture passing through the intake passage 6a of the insulator 6 when the engine is started at a low temperature is heated by the PTC heater 7 provided in the passage 6a. When the temperature of the engine body 1 rises, power supply from the battery is stopped and heating by the PTC heater 7 is terminated.

While the engine is operating, the intake passages 6a and 6b of the insulator 6 are under negative pressure, but the intake passages 6a and 6b are sealed by an O-ring 24 on the carburetor 3 side, and a gasket on the intake manifold 4 side. 23, so the insulator 6 and carburetor 3 or intake manifold 4
Outside air will not flow in between the Lead wires 12, 13, 14 and each leg 10 of the PTC heater 7,
Working holes 20, 2 for joining with 9a, 9b, 9c
0, ... are located outward from the O-ring 24, but the working hole 20 is filled with sealing resin 22 and sealed, so outside air or moisture can pass through the working hole 20 and the insertion hole of the rivet 21. There is no inflow. Therefore, there is no problem even if the carburetor 3 is supported in a floating state with respect to the insulator 6.

When the engine is stopped after being operated under a high load, the engine body 1 becomes high temperature, and the inside of the intake passages 6a and 6b may become positive pressure due to evaporated fuel. However, there is no fear that the evaporated fuel will leak from the gap between the carburetor 3 and the insulator 6.

In this way, the PTC heater 7 can be easily attached to the insulator 6, while
It becomes possible to ensure the sealing performance of the intake passages 6a and 6b.

In addition, in the above embodiment, the PTC heater 7
Legs 9b and 9c provided in the enclosure 9 of
The lead wires 14 are also connected between the insulators 6 and 6, but the lead wires 14 are provided for reinforcing the insulator 6.
It is not necessarily necessary to connect these. If the PTC heater 7 is sufficiently firmly fixed to the insulator 6 by the two legs 10 and 9a, the other legs 9b and 9c can be omitted.

In addition, the lead wires 12 and 13 also serve as reinforcing materials for the insulator 6, and if it is necessary to strengthen the reinforcement,
The lead wires 12 and 13 may be extended and joined to the PTC heater 7 at the intermediate portion thereof.

Furthermore, in the above embodiment, the PTC heater 7 is attached to the insulator 6, but the present invention is not limited to the PTC heater 7, but can also be applied to cases where other electric heaters are attached to the insulator 6. It is something. In such a case, the electric heater and the lead wires 12,1
In addition to riveting, spot welding or the like may be used to join the third member, and the present invention is also effective in such cases.

(Effect of the invention) As is clear from the above explanation, according to the invention, the lead wire is buried inside the insulator,
Since the electric heater is connected to the lead wire, the electric heater can be attached to the insulator and the electrical connection for supplying power to the electric heater can be made at the same time. The insulator is reinforced by this.

The insulator is provided with a working hole that reaches the joint between the lead wire and the electric heater, and the joint is open on both sides of the insulator, making it possible to perform reliable joints such as riveting. This makes it possible to make the bond heat resistant and reliable. In addition, the recess and the working hole allow the lead wire buried inside the insulator to be held during molding of the insulator, making it possible to accurately position the lead wire.

Moreover, since the working hole is filled with a sealing resin and sealed after the joining operation, there is no possibility that outside air or moisture will flow in through the working hole, or that fuel will not leak. Therefore,
The position of the working hole may be located outside of the O-ring, or the O-ring may be located near the insulator's intake passage to provide effective sealing.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view of essential parts showing an embodiment of the intake air heating device according to the present invention, FIG. 2 is an exploded perspective view of the intake air heating device, and FIG. 3 is a bottom view of the intake air heating device. , FIG. 4 is a partially cutaway schematic side view of the engine equipped with the intake air heating device. 1... Engine body, 3... Carburetor, 4... Intake manifold, 6... Insulator, 6a, 6
b...Intake passage, 7...PTC heater (electric heater), 8...PTC heater body, 9...enclosure, 9a, 9b, 9c...legs, 10...legs, 11...recesses, 12, 13, 14... Lead wire, 20... Working hole, 21... Rivet, 22...
...Sealing resin, 23...Gasket, 24...
O-ring.

Claims (1)

[Claims for Utility Model Registration] An insulator 6 installed between a carburetor 3 and an intake manifold 4 and provided with an intake passage 6a that guides intake air supplied from the carburetor 3 to the intake manifold 4; An electric heater 7 that is attached to the intake passage 6a and can heat the intake air passing through the intake passage 6a.
In an engine intake air heating device comprising: Lead wires 12 and 13 connected to an external power source are buried in the insulator 6, and the electric heater 7 is connected to a part of the lead wires 12 and 13. At the same time, the insulator 6 is connected to the lead wire 12,
An intake air heating device for an engine, characterized in that a joining hole 20 is formed that reaches the joint between the electric heater 7 and the electric heater 7, and the joining hole 20 is filled with a sealing resin 22.