JPH0229247Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention relates to an intake air heating device that heats intake air supplied to the combustion chamber of an engine using an electric heater. is attached to an insulator installed 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 is 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, a conductor is usually buried inside the insulator, and one end of the conductor is
While ensuring that the PTC heater is connected,
The other end is made to protrude from the side of the insulator as a terminal. Then, an insulated lead wire is connected to the terminal, and power is supplied from a power source such as a battery through the lead wire.

In that case, conventionally, the conductor buried in the insulator was relatively short, and the terminal was made to protrude from the vicinity of the PTC heater. Therefore, even in the case of an insulator having two intake passages connected to the primary passage and the secondary passage of a two-barrel carburetor, the terminal is located on the side of the primary passage where the PTC heater is attached. It was about to be established.

(Problems to be Solved by the Invention) However, the PTC heater reaches a high temperature of, for example, about 200° C. during operation. The heat is then transferred to the terminal through the conductor to which the PTC heater is bonded. Therefore, if the length of the conductor is short, the terminal will reach a considerable high temperature. Furthermore, if the terminal is close to the PTC heater, not only heat transfer through such a conductor but also direct heating from the heater is added, so the terminal becomes even hotter.

When the terminal reaches such a high temperature, the high heat is transferred to the lead wire connected to it, so it is necessary to use a heat-resistant lead wire. Further, the passage and the joint between the terminal and the lead wire are covered with a waterproof cover, and the waterproof cover is also required to have heat resistance. Furthermore, a problem arises in that a joining means with low heat resistance such as soldering cannot be used to join the terminal and the lead wire.

The present invention was developed in view of these problems, and its main purpose is to remove electric heaters such as PTC heaters attached to insulators.
The purpose is to ensure that the heat transferred to the terminals that take in the electricity to supply it is reduced.

(Means for solving the problem) In order to achieve this object, the present invention provides an insulator having a first passage and a second passage connected to the primary passage and the secondary passage of the carburetor, respectively. A conductor buried in the insulator and having one end joined to the electric heater attached to the first passage is extended to the side of the second passage away from the first passage, and the other end is formed. The terminal is made to protrude from the side surface on the second passage side.

(Function) By providing the terminal on the side of the insulator on the second passage side away from the first passage, a conductor can be connected from the terminal to the electric heater installed in the first passage. becomes long. Therefore, the heat transferred from the electric heater to the conductor is radiated along the conductor. Furthermore, since the terminal is located away from the electric heater, direct thermal influence from the heater is also suppressed. This prevents the terminal from becoming too hot.

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

1 to 4 show an embodiment of the intake air heating device according to the present invention, FIG. 1 is a bottom view of the intake air heating device, and FIG. 2 is a partially cutaway view of the intake air heating device. It is a cutaway perspective view. Further, FIG. 3 is an enlarged sectional view of a main part of the intake system of an engine equipped with the intake air heating device, and FIG. 4 is a schematic side view of the whole.

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 of a two-barrel type, and includes a primary passage 3 that is open even when the load is low, and a secondary passage 3b that is open only when the load is high.

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 having heat and electrical insulation properties such as Bakelite or phenolic resin, and has a primary passage 3a and a secondary passage 3b of the carburetor 3 in its center, respectively. First and second passages 6a, 6b are provided which connect to the manifold 4. An RTC heater 7, which is an electric heater, is attached to one of the first passages 6a, which is connected to the primary passage 3a of the vaporizer 3.

As shown in Figures 1 and 2, this PTC
The 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 thereof. Its outer periphery is covered with a metal enclosure 9. In this enclosure 9,
Three leg portions 9a, 9b, and 9c are provided. In addition, this enclosure 9 is attached to the PTC heater 7.
A further leg 10 is provided which is insulated from the base.
As shown in FIG. 3, the enclosure 9 is electrically connected to one side of the honeycomb-shaped partition of the PTC heater body 8, and the other leg 10 is electrically connected to the other side of the partition. connected.

A recess 11 into which a PTC heater is inserted and accommodated is provided on the lower surface of the insulator 6 on the first passage 6a side, that is, on the surface on the intake manifold 4 side. As shown in FIG. 1, three metal strip-shaped conductors 12, 13, and 14 are buried inside the insulator 6. The inner ends of the two conductors 12 and 13 are exposed in the recess 11 of the insulator 6 at positions corresponding to the legs 10 and 9a of the PTC heater 7, respectively. Further, both ends of the other conductor 14 are connected to the leg portions 9b and 9b of the PTC heater 7, respectively.
It is exposed in the recess 11 at a position corresponding to 9c. In this way, PTC heater 7
into the recess 11, and each conductor 12, 13, 1
4 and each leg portion 10, 9a, 9b of the PTC heater 7,
9c is joined with rivets 15 etc.,
These are electrically connected, and
The PTC heater 7 is configured to be fixedly attached to the insulator 6.

A pair of conductors 12 and 13 connected to the legs 10 and 9a of the PTC heater 7 are connected from the side of the first passage 6a of the insulator 6 to which the PTC heater 7 is attached to the first passage 6a of the second passage 6b. Extending inside the insulator 6 to the non-adjacent side, and protruding outward from the side of the insulator 6 at the side of the second passage 6b,
Terminals 16, 17 are formed by the outer ends thereof. The exposed ends of insulated lead wires 18 are connected to the terminals 16 and 17 by spot welding or the like, and the lead wires 18 are connected to a vehicle battery or the like via a connector 19. It is designed to be connected to an external power source. The joints between the terminals 16 and 17 and the lead wires 18 are covered with a waterproof cover 20.

These conductors 12, 13, and 14 are held in a predetermined position within the mold during molding of the insulator 6, and are integrally buried within the insulator 6 by injecting the insulator base material into the mold. . Therefore, holes 21, 21, . . . for holding the conductors 12, 13, 14 are left in the insulator 6. This hole 21
are the conductor 1 from the upper and lower surfaces of the insulator 6
It has reached 2, 13, and 14.

When attaching the PTC heater 7 to the insulator 6, insert it from the bottom side of the insulator 6, house it in the recess 11, and then attach the PTC heater 7 to the insulator 6.
Each leg 10, 9a, 9b, 9c is a conductor 12,
13 and 14 so that they overlap each other. Then, rivet these 15, 15,...
Join by. The hole 22 for the joining work is
After the joining work is completed, as shown in FIGS. 2 and 3, an epoxy resin 23 is filled and sealed.

The insulator 6 to which the PTC heater 7 is attached in this way is as shown in FIG.
The carburetor 3 and the intake manifold 4 are sandwiched and fixed via an O-ring 24 and a gasket 25, respectively. Therefore, vaporizer 3
A small gap is formed between and the insulator 6. Then, as shown in FIG. 1, lead wires 18 are joined to terminals 16 and 17 protruding from the side surface of the insulator 6, and a waterproof cover 20 is applied to the joint portion.

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 first passage 6a of the insulator 6. At the same time, power is supplied from the battery through the lead wire 18. As a result, the terminal 16, the conductor 12, and the leg portion 1 of the PTC heater 7 are provided on one side of the honeycomb-shaped partition wall constituting the PTC heater main body 8.
0 and the other side of the partition wall has
Electricity is supplied through the terminal 17, the conductor 13, the leg 9a of the PTC heater 7, and the enclosure 9. Therefore, voltage is applied to the partition wall from both sides, and the partition wall generates heat. In this way, when the engine is started, the first
The air-fuel mixture passing through the passage 6a 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.

As the PTC heater main body 8 generates heat in this way, the heat is transmitted from the joints to the conductors 12 and 13 through the legs 10 and 9a.
This heat is further transferred to the terminals 16 and 17, but the terminal 1 of the conductors 12 and 13
Since the length up to 6 and 17 is long, a considerable amount of heat is absorbed by the insulator 6 during that time. In addition, the vaporizer 3 of the insulator 6
A certain amount of heat is also radiated through the holes 21, 21, . . . formed in the side surfaces and the gap between the carburetor 3 and the insulator 6. Therefore, the amount of heat transferred to the terminals 16, 17 is relatively small, and the terminals 16, 17 are prevented from becoming high temperature. Further, since the terminals 16 and 17 themselves are also located apart from the PTC heater main body 8, the direct thermal influence of the PTC heater 7 can be suppressed to a small level.

Furthermore, by embedding the metal strip-shaped conductors 12 and 13 extending from the side of the first passage 6a to the side of the second passage 6b in the insulator 6, the insulator 6 is Becomes reinforced. The strength of the insulator 6 can be further increased by extending the conductor 14 buried on the opposite side of the first passage 6a to the side of the second passage 6b.

Furthermore, as shown in FIG.
2 and 13 may be extended so as to surround the second passage 6b of the insulator 6, and the terminals 16 and 17 at their ends may be made to protrude from the side opposite to the first passage 6a side. . If this is done, the conductors 12 and 13 will be longer, so that the temperature rise of the terminals 16 and 17 will be further suppressed, and their reinforcing effect will be greater.

In addition, in the above explanation, the insulator 6 has
Although the PTC heater 7 is assumed to be attached, other electric heaters may be attached as the intake air heating device. It will be obvious that the embodiments can be applied to such cases as well.

(Effects of the invention) As is clear from the above description, according to the invention, in an insulator having first and second passages respectively connected to the primary passage and the secondary passage of the carburetor, the first passage is electrically connected. At the same time as the heater is attached, the conductor buried in the insulator and connected to the electric heater is extended to the side of the second passage away from the first passage and protrudes from the side of the second passage. Their bodies become longer, and the heat transmitted from the electric heater is absorbed along the way. Therefore, the temperature rise of the terminal formed by the protruding end of the conductor is reduced, and the lead wire connected to the terminal and the waterproof cover covering the joint are also heat resistant. It becomes possible to use an inexpensive one with low .

[Brief explanation of the drawing]

FIG. 1 is a bottom view showing an embodiment of the intake air heating device according to the present invention, FIG. 2 is a partially cutaway perspective view of the intake air heating device, and FIG. 3 is an engine equipped with the intake air heating device. 4 is a partially cutaway schematic side view showing the entire intake system, and FIG. 5 is a bottom view showing another embodiment of the intake air heating device according to the present invention. It is. DESCRIPTION OF SYMBOLS 1...Engine body, 3...Carburizer, 3a...Primary passage, 3b...Secondary passage, 4...Intake manifold, 5...Intake system, 6...Insulator, 6a
...first passage, 6b...second passage, 7...PTC heater (electric heater), 8...PTC heater main body, 9...enclosure, 9a, 9b, 9c...leg, 10...leg, 11...recess, 12 , 13, 14... conductor, 1
5... Rivet, 16, 17... Terminal, 18...
Lead wire, 20...waterproof cover.

Claims (1)

[Claims for Utility Model Registration] A first passage 6a installed between the carburetor 3 and the intake manifold 4 and connected to the primary passage 3a and secondary passage 3b of the carburetor 3, respectively.
and an insulator 6 provided with a second passage 6b.
and an electric heater 7 which is provided in the first passage 6a of the insulator 6 and can heat the intake air passing through the first passage 6a, and is embedded in the insulator 6 and has one end joined to the electric heater 7. The other ends of the conductors 12 and 13 protrude outward from the side surface of the insulator 6 at a peripheral surface portion of the second passage 6b that is not adjacent to the first passage 6a. heating device.