JPS6221236B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fuel vaporization promoting device for an internal combustion engine.

[Conventional technology]

2. Description of the Related Art Many fuel vaporization promoting devices using ceramic heaters have been proposed for, for example, internal combustion engines for automobiles, in order to promote the vaporization of fuel supplied from a carburetor.

[Problem that the invention seeks to solve]

However, the intake pipe of an internal combustion engine equipped with such a fuel vaporization promoting device vibrates as the engine is operated, and especially in automobiles, in addition to the vibrations caused by the operation of the internal combustion engine, the intake pipes also vibrate due to the operation of the internal combustion engine. is added. Therefore, if a ceramic heater is installed in an intake pipe that is subject to such vibrations, there is an extremely high risk that the ceramic heater will be damaged by the vibrations.If the ceramic heater were to be damaged, the internal combustion It may be inhaled into the engine's cylinders, rendering the internal combustion engine inoperable.

In order to prevent the damage caused by vibrations as described above, it is necessary to separately provide an elastic body capable of absorbing vibrations in the direction in which the ceramic heater receives vibrations, which poses the problem of complicating the overall configuration of the device. arise.

[Means for solving problems]

In view of the above-mentioned problems, an object of the first invention of the present application is to prevent the ceramic heater from being damaged by vibration even if the ceramic heater is fixed in the intake pipe which is subject to vibrations due to the operation of an internal combustion engine. An object of the present invention is to provide a fuel vaporization promoting device for an internal combustion engine that can sufficiently prevent the fuel vaporization from occurring.In order to achieve the above object, the first invention of the present application includes a thin film electrode on the surface that generates heat when energized. A fuel vaporization promoting device for an internal combustion engine, comprising a ceramic heater formed with a ceramic heater, the ceramic heater being fixed along the inside of an intake pipe directly below a fuel supply means having a passage through which an air-fuel mixture flows, A cushion member made of metal wool is disposed between one of the opposing surfaces of the ceramic heater and the intake pipe, and a cushion member made of a metal wool material is arranged on the other surface of the ceramic heater, and a conductive material is provided on the other surface of the ceramic heater to cover the entire surface. The fuel vaporization promoting device for an internal combustion engine is characterized in that a pressing member is fixed, and the cushioning member and the pressing member also serve as a part of the current supply path for the ceramic heater.

Further, it is an object of the second invention of the present application to further suppress heat being taken away from the ceramic heater by the air-fuel mixture containing already vaporized fuel, and to heat only the liquid fuel from the fuel supply means. It is an object of the present invention to provide an efficient fuel vaporization promoting device for an internal combustion engine, and in order to achieve the above object, the second invention of the present application includes a ceramic heater having a thin film electrode formed on its surface, which generates heat when energized. To promote fuel vaporization of an internal combustion engine, this ceramic heater is fixed in a recess formed at the bottom of an intake pipe wall located directly below an intake pipe that is connected to a fuel supply means having a passage through which an air-fuel mixture flows. In the device, the ceramic heater has a flat plate shape, and a cushion member made of metal wool is disposed between one of the opposing surfaces of the ceramic heater and the intake pipe wall in the recess. and fixing to the other surface of the ceramic heater a holding member made of a conductive material that covers the entire surface, so that the upper surface of the ceramic heater is approximately in the same layer as the bottom of the intake pipe wall other than the recessed portion. In addition, the fuel vaporization promoting device for an internal combustion engine is characterized in that the cushion member and the pressing member also serve as a part of the current supply path for the ceramic heater.

〔Example〕

Embodiments of a fuel vaporization promoting device in which the present invention is applied to an automobile internal combustion engine will be described below. 1 to 3, 1 is a carburetor serving as a fuel supply means, 2 is an intake pipe connecting the internal combustion engine 3 and the carburetor 1, and 4 is a concave portion of the intake pipe 2 directly below the carburetor 1. Cooling water for the internal combustion engine 3 is circulated through a cooling water passage box provided on the outer surface of the riser wall 2a. Reference numeral 5 denotes a plate-shaped ceramic heater according to the present invention, which is made of, for example, barium titanate (BaTiO ₃ ), has a positive temperature coefficient of resistance, and has a resistance value that suddenly changes at a specific temperature (for example, 200°C). has an increasing Curie point. Thin film electrodes 6 and 7 are formed on opposing surfaces of the plate-shaped ceramic heater 5. Note that the electrodes 6 and 7 are formed, for example, by applying and baking a silver paste or by chemical plating. Reference numeral 8 denotes a first metal electrode plate fixed to the inner surface of the riser wall 2a via metal bolts 9. 10 is a metal second electrode plate having a window portion 10a. The ceramic heater 5 is fixed between the first and second electrode plates 8 and 10, and a cushion member 1 made of heat-resistant metal wool is used to fix the ceramic heater 5.
1 to the first electrode plate 8 and the electrode 7 of the ceramic heater 5
A heat-resistant metal wire mesh 12 is placed between the second electrode plate 10 and the ceramic heater 5 and serves as a holding member.
Ceramic heater 5 on the electrode 6 side is connected between the electrode 6 of
It is arranged so as to cover the entire surface. In addition, the second
The electrode plate 10 is connected to the first
It is fixed to the electrode plate 8. Note that the electrode 6 of the ceramic heater 5 includes a wire mesh 12, a second electrode plate 10, a metal bolt 14, a metal terminal 17, and a lead wire 18.
The electrode 7 is taken out to the outside via the cushion member 11 and the first electrode plate 8, and is grounded to the riser wall 2a. 19 is a heat-resistant rubber ring for preventing short circuit between the lead wire 18 and the riser wall 2a;
0 is a battery which is an in-vehicle power supply, and 21 is a switch.

As shown in FIG. 1, the fuel vaporization accelerator having the above structure is installed in the recess of the riser wall 2a directly below the carburetor 1, and the upper surface of the ceramic heater 5 is located outside the recess of the riser wall 2a. It is arranged so as to be almost in the same layer as the bottom of the tube 2.

Next, the operation of the above configuration will be explained. When the switch 21 is closed, each electrode 6, 7 of the ceramic heater 5 is energized and the ceramic heater 5 generates heat. At this time, since the temperature of the ceramic heater 5 itself is low, the resistance value is small and a large current flows through it, resulting in a high temperature in a very short time. Immediately after such a cold start, the fuel is poorly atomized in the vaporizer 1, and this fuel collides with the throttle valve 1a and becomes droplets, penetrating the window 10a of the second electrode plate 10 and the wire mesh 12. It passes through the hole 12a and drops onto the surface of the ceramic heater 5 (on the electrode 6). This dripped liquid fuel is well vaporized by the heat of the ceramic heater 5, so compared to the case where it is sucked into the internal combustion engine 3 as a liquid, there is no suffocation immediately after starting, and there is no warming up after starting. The machine runs well and there are no misfires. In addition, when the ceramic heater 5 becomes high in temperature and reaches the Curie point, the resistance value increases and only a small amount of current flows, so the temperature decreases.When the temperature decreases, the resistance value decreases and a large current flows. The temperature rises again. Because this process is repeated, in the unlikely event of a failure, the ceramic heater 5
Even if the ceramic heater 5 is continuously energized, the ceramic heater 5 will not overheat. After the warm-up operation is completed, the riser wall 2a is heated by the cooling water passing through the cooling water passage box 4, and the fuel dripping onto the inner surface of the riser wall 2a is vaporized by the heat of this cooling water. Note that by promoting the vaporization of the fuel even after the warm-up operation is completed, suffocation during acceleration is prevented and smooth acceleration is achieved.

By the way, since the intake pipe 2 is connected to the internal combustion engine 3, it is subjected to vibrations when the internal combustion engine 3 is operating.
This vibration is transmitted to the ceramic heater 5 via the first electrode plate 8, but most of the vibration is absorbed by the cushion member 11 due to the vertical and horizontal deformation freedom of the metal wool material that constitutes the cushion member 11. The vibration is not transmitted to the heater 5, so damage to the ceramic heater 5 due to vibration can be prevented. Further, even if the ceramic heater 5 is damaged due to strong vibration, it can be prevented from being scattered by the wire mesh 12, and the broken pieces of the ceramic heater 5 will not be sucked into the internal combustion engine 3.

In addition, since the cushion member 11 and the wire mesh 12 also serve as a part of the energizing path for the ceramic heater 5, it is possible to prevent the ceramic heater 5 from being damaged due to vibrations, and to prevent the ceramic heater 5 from being damaged due to vibration, without complicating the overall configuration of the device. This makes it possible to prevent scattering in the event of damage.

Furthermore, in response to vibrations from the internal combustion engine 3, the metal wool material sways between the contact area with the ceramic heater 5 and the contact area with the first electrode 8 in order to absorb the vibrations. Ceramic heater 5
The phenomenon of rubbing the electrode 7 of the ceramic heater 5 is rare, and the electrode 7 of the ceramic heater 5 is not damaged.
Even if the electrode 7 is partially damaged, there are many contact points between the electrode 7 and the metal wool material, so even if the current flow deteriorates in one part, the electrical connection between the two will be maintained at many other contact points. Sufficient connections are ensured.

Furthermore, the above device including the ceramic heater 5 is disposed within the recess of the riser wall 2a, and the upper surface of the ceramic heater 5 is arranged to be approximately on the same level as the bottom surface of the intake pipe wall other than the recess. As a result, only the upper surface of the ceramic heater 5 is exposed to the flow of the air-fuel mixture in the intake pipe 2. Therefore, the amount of heat taken away by the air-fuel mixture is reduced, and the liquid dripping onto the upper surface of the ceramic heater 5 is When the fuel is heated by the ceramic heater 5 and vaporized, the fuel is immediately heated to the internal combustion engine 3 by the flow of the air-fuel mixture flowing near the upper surface of the ceramic heater 5.
is sent to each cylinder side. In other words, the heat of the ceramic heater 5 efficiently contributes to the liquid fuel, and the fuel vaporized by the heat of the ceramic heater 5 is immediately supplied to the internal combustion engine 3 without remaining near the ceramic heater 5. It becomes like this.

Furthermore, the ceramic heater 5 is connected to the riser wall 2.
Since it is provided in the recessed part a, even if the ceramic heater 5 is damaged, the broken piece of the ceramic heater 5 can be kept in this recessed part.

Further, since the liquid fuel is directly dripped onto the surface of the ceramic heater 5 through the through hole 12a of the wire mesh 12, the heat of the ceramic heater 5 is directly applied to the liquid fuel, and therefore the heat of the ceramic heater 5 is efficiently transferred to the surface of the ceramic heater 5. It will contribute to fuel. Note that this effect is not impaired in any way even if the through-hole 12a of the wire mesh 12 is made small enough to prevent a damaged ceramic heater from scattering.

The present invention is not limited to the above embodiments, but can be modified in various ways as described below.

(1) Although the holding member for preventing the broken ceramic heater 5 from scattering is made of a wire mesh, it may be made of a conductive material having a large number of through holes, such as a punched plate or a louver plate.

(2) The shape of the ceramic heater 5 may be a honeycomb-shaped flat plate with a large number of passages provided in the axial direction.
When using this honeycomb-shaped ceramic heater, it is necessary to pass a heat exchange medium through its many passages, so one end face of the honeycomb-shaped ceramic heater has a second window 10a shown in FIG.
Although it is sufficient to attach the electrode plate 10 and the wire mesh 12, it is necessary to attach an electrode plate having a window 10a similar to the second electrode plate 10 on the other end surface.

(3) The cushion member 11 may be disposed directly between the riser wall 2a and the electrode 7 of the ceramic heater 5 by omitting the first electrode plate 8 shown in FIG.

(4) As the ceramic heater 5, a ceramic heater made of silicon carbide (SiC) other than barium titanate, which has positive resistance temperature characteristics, can be used.

〔Effect of the invention〕

As described above, the first invention of the present application includes a ceramic heater that generates heat when energized and has a thin film electrode formed on its surface. A fuel vaporization accelerating device for an internal combustion engine fixed along the inside of an intake pipe directly below a supply means, wherein a metal wool material is provided between one of the opposing surfaces of the ceramic heater and the intake pipe. A holding member made of an electrically conductive material is fixed to the other surface of the ceramic heater, and the holding member is made of a conductive material and covers the entire surface of the ceramic heater. Since the fuel vaporization promoting device for an internal combustion engine is characterized in that the fuel vaporization promoting device is characterized in that the fuel vaporization promoting device is characterized in that the fuel vaporization promoting device is characterized in that the fuel vaporization promoting device is characterized in that the fuel vaporization promoting device is used as the fuel vaporization promoting device for the internal combustion engine, it has excellent effects as shown below.

(b) Most of the vibrations from the internal combustion engine are absorbed by the cushion member due to the vertical and horizontal deformation freedom of the metal wool material that makes up the cushion member, and are not transmitted to the ceramic heater, thereby preventing damage to the ceramic heater. .

(b) Even if the ceramic heater is damaged due to strong vibration, the holding member that covers the entire surface of the ceramic heater can prevent the broken pieces of the ceramic heater from scattering, and the broken pieces of the ceramic heater will be sucked into the internal combustion engine. Never.

(c) Since the cushion member and the holding member also serve as part of the current supply path for the ceramic heater, the effects (a) and (b) above can be obtained without complicating the configuration of the entire device.

(d) In response to vibrations, the metal wool material that makes up the cushion member sways to absorb vibrations between the contact area with the ceramic heater and the contact area with the intake pipe side. There is almost no chance of scratching the thin film electrode.

(E) Even if the metal wool scrapes and damages a part of the thin film electrode, there are many contact points between the electrode and the metal wool, so even if the current flow deteriorates in one part, it will not affect the other parts. Many contact points ensure sufficient electrical connection between the two.

Furthermore, according to the second invention of the present application, the present invention is provided with a ceramic heater having a thin film electrode formed on its surface, which is invented by energization, and the ceramic heater is connected to a fuel supply means having a passage through which an air-fuel mixture flows inside. A fuel vaporization promoting device for an internal combustion engine fixed in a recess formed in a bottom of an intake pipe wall located directly below an intake pipe, the ceramic heater having a flat plate shape,
A cushion member made of a metal wool material is disposed between one of the opposing surfaces of the ceramic heater and the intake pipe wall in the recess, and a cushion member made of a metal wool material is provided on the other surface of the ceramic heater. A holding member made of a conductive material covering the ceramic heater is fixed so that the upper surface of the ceramic heater is in approximately the same layer as the bottom of the intake pipe wall other than the recess, and the cushioning member and the holding member are fixed to the ceramic heater. Since the fuel vaporization promoting device for an internal combustion engine is characterized in that a part of the energizing path for the heater is also used, the effects (a), (b), (c), and (d) obtained in the first invention are obtained. , (e), it also has the following excellent effects.

(F) Since only the upper surface of the ceramic is exposed to the flow of the air-fuel mixture in the intake pipe, the amount of heat taken away by the air-fuel mixture in the ceramic heater is reduced, and the liquid fuel that has dripped on the upper side of the ceramic heater is When it is heated and vaporized by the heat from the heater, it is immediately sent to the cylinders of the internal combustion engine along with the flow of air-fuel mixture near the top of the ceramic heater, so the heat from the ceramic heater efficiently contributes to the liquid fuel. At the same time, the vaporized fuel is immediately supplied to the internal combustion engine without remaining near the ceramic heater.

(g) Since the ceramic heater is disposed within the recess at the bottom of the intake pipe wall, even if the ceramic heater is damaged, the damage to the ceramic heater can be kept within the recess.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of an intake system portion of an internal combustion engine equipped with the device of the present invention, Fig. 2 is a perspective view showing an embodiment of the device of the present invention, and Fig. 3 is a sectional view taken along line AA in Fig. 2. It is. DESCRIPTION OF SYMBOLS 1... Carburizer serving as fuel supply means, 2... Intake pipe, 2a... Riser wall having a recess, 3... Internal combustion engine, 5... Ceramic heater, 6, 7... Thin film electrode, 11... A cushion member made of metal wool material, 12... A wire mesh forming a pressing member, 12a...
...through hole.

Claims (1)

[Scope of Claims] 1. A ceramic heater that generates heat when energized has a thin film electrode formed on its surface, and that the ceramic heater is installed inside an intake pipe directly below a fuel supply means that has a passage through which an air-fuel mixture flows. A fuel vaporization accelerating device for an internal combustion engine fixed along a pipe, wherein a cushion member made of a metal wool material is disposed between one of the opposing surfaces of the ceramic heater and the intake pipe, and A holding member made of a conductive material is fixed to the other surface of the ceramic heater, and the holding member is made of a conductive material and covers the entire surface, and the cushioning member and the holding member also serve as a part of the current supply path for the ceramic heater. Fuel vaporization accelerator for internal combustion engines. 2. The fuel vaporization promoting device for an internal combustion engine according to claim 1, wherein the holding member has a large number of through holes. 3. The fuel vaporization promoting device for an internal combustion engine according to claim 2, wherein the pressing member is a wire mesh. 4 An intake pipe that is equipped with a ceramic heater that generates heat when energized and has a thin film electrode formed on its surface, and that is located directly below an intake pipe that connects this ceramic heater to a fuel supply means that has a passage through which an air-fuel mixture flows inside. The fuel vaporization accelerator for an internal combustion engine is fixed in a recess formed at the bottom of a wall, wherein the ceramic heater is configured in a flat plate shape, and one of the facing surfaces of the ceramic heater and the recess are provided. A cushion member made of metal wool is disposed between the inner wall of the intake pipe, and a presser member made of a conductive material is fixed to the other surface of the ceramic heater, covering the entire surface of the ceramic heater. An internal combustion engine characterized in that the surface thereof is substantially in the same layer as the bottom of the intake pipe wall other than the recess, and the cushion member and the pressing member also serve as a part of the current supply path for the ceramic heater. Fuel vaporization accelerator.