JP4009987B2 - Heater for preventing icing of vaporizer - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a carburetor that adjusts and controls the amount and concentration of an air-fuel mixture supplied to an engine, and in particular, an icing prevention heater (an icing prevention heater) that prevents icing of a bypass hole that opens toward the end of a throttle valve. Mounting).
[0002]
[Prior art]
A conventional heater for preventing icing of a vaporizer will be described with reference to FIG.
Reference numeral 1 denotes a carburetor body which is formed by penetrating an intake passage 2 laterally, and the intake passage 2 is controlled to be opened and closed by a plate-shaped butterfly-type throttle valve 3.
The throttle valve 3 is screwed onto a throttle valve shaft 4 that is rotatably supported by the carburetor body 1. When the driver rotates the throttle valve shaft 4, the throttle valve 3 is connected to the intake passage 2. Open and close.
The lower concave portion 1A of the vaporizer body 1 is closed by a cup-shaped float chamber body 5 to form a float chamber 6. The float seat 6 has a valve seat 7 and a float that opens and closes the valve seat 7. A constant fuel liquid level XX is formed and held by a constant liquid level control mechanism comprising the valve 8 and the float 9 for imparting the opening / closing operation to the float valve 8.
Further, a bypass chamber 10 is provided below the intake passage 2 of the carburetor body 1 along the longitudinal axis direction YY of the intake passage 2, and a bypass hole 11 extends from the bypass chamber 10 into the intake passage 2. Open and drilled. The bypass hole 11 opens toward the end of the throttle valve 3, and the bypass hole 11 is mainly responsible for supplying low-speed fuel during low-speed operation of the engine.
A heater mounting hole 12 is recessed from the lower end 5B of the floating chamber body 5 toward the upper side of the bypass chamber 10, and a female screw is formed upward from the lower end 5B.
Then, the electric heater 13 that generates heat from the internal heating element when energized is screwed into the heater mounting hole 12.
The electric heater is energized during operation of the engine. According to this, the bypass chamber 10 and the bypass hole 11 are warmed by the heat generated by the electric heater 13, and the icing of the bypass hole 11 is prevented.
[0003]
[Problems to be solved by the invention]
Such a conventional vaporizer has the following problems.
First, the bypass chamber 10 including the bypass hole 11 cannot be effectively warmed by the electric heater 13.
This is because the heat generating portion of the electric heater 13 has a cylindrical shape, and the heat generating portion is formed by a side portion 13A having a large heat generating area on the outer periphery of the cylindrical portion and an upper bottom portion 13B having a small heat generating area at the tip of the cylindrical portion. This is because the side portion 13A having the large heat generation area is arranged orthogonal to the longitudinal axis YY of the intake passage 2, and thus the large capacity discharged from the side portion 13A is large. This is because the heat first warms the side wall 5A of the floating chamber body 5, and then this heat is transmitted upward to warm the bypass chamber 10 and the bypass hole 11.
In addition, there is a space S between the upper end of the heater mounting hole 12 and the upper bottom 13B of the electric heater 13 in terms of machining of the female screw. In order to enhance the heat transfer effect from the space S The grease is sealed in this portion, which greatly impairs the assembly of the electric heater 13.
Further, the side portion 13A having a large heat generation area of the electric heater 13 is arranged along the fuel storage direction (vertical direction in the drawing) in the floating chamber body 5, and according to this, the fuel in the floating chamber 6 is disposed. Is easy to be warmed by the side wall 5A, which is not preferable in suppressing fuel evaporation in the float chamber 6.
Furthermore, if a current-carrying harness (not shown) is attached to the electric heater 13, the overall height of the carburetor is substantially increased, and this impedes the degree of freedom for mounting on the engine.
[0004]
The carburetor according to the present invention has been made in view of the above problems, and an object thereof is to provide a heater for preventing icing of a carburetor that can effectively warm a bypass hole including a bypass chamber. In addition, it is intended to suppress fuel evaporation in the float chamber by the electric heater.
[0005]
[Means for achieving the object]
The heater for preventing icing of a carburetor according to the present invention is a carburetor main body in which an intake passage is drilled laterally to achieve the above-mentioned purpose,
A throttle valve for opening and closing the intake passage;
A bypass hole that opens from the bypass chamber recessed along the longitudinal axis direction of the intake passage to the end of the throttle valve and opens into the intake passage;
In a carburetor comprising a float chamber in which a constant fuel liquid level is formed by a lower recess of the vaporizer body and a float chamber body disposed opposite thereto,
A heater mounting boss is formed integrally with the float chamber body and formed parallel to the longitudinal axis of the intake passage, and a space is formed between the tip of the heater mount boss and the side wall of the float chamber body. In the heater mounting boss, the longitudinal axis of the electric heater is arranged parallel to the longitudinal axis of the intake passage and the fuel level formed in the float chamber, and the front end of the electric heater faces the space. It is arranged .
[00 06 ]
[Action]
According to the icing prevention heater of the carburetor of the present invention, the side portion of the electric heater having a large heat generation area is arranged in parallel with the intake passage and the fuel level, so that the bypass chamber and the bypass hole can be effectively warmed. Can suppress the occurrence of icing.
In particular, when the side portion of the electric heater is arranged in parallel with the fuel liquid level, the fuel in the float chamber is difficult to be warmed, thereby suppressing fuel evaporation in the float chamber.
Further , since a space is formed between the front end of the electric heater and the side wall of the float chamber body, and the front end of the electric heater faces the space , the side wall of the float chamber body by the front end of the electric heater is arranged. Therefore, the fuel evaporation in the float chamber can be further suppressed.
[00 07 ]
【Example】
An embodiment of a heater for preventing icing of a vaporizer according to the present invention will be described below with reference to FIG.
2 that are the same as those in FIG. 2 are denoted by the same reference numerals and description thereof is omitted.
Reference numeral 20 denotes a heater mounting boss formed integrally with the float chamber main body 5, and this heater mount boss 20 is formed substantially parallel to the longitudinal axis YY of the intake passage 2 and the fuel liquid level XX in the float chamber. The
Further, a space portion Z is formed between the tip end portion 20 </ b> A of the heater mounting boss 20 and the side wall 5 </ b> A of the floating chamber body 5.
The heater mounting boss 20 is provided with a heater mounting hole 21 from the rear end 20C toward the front end 20A, and a female screw is formed in the heater mounting hole 21.
The heater mounting hole 21 is preferably formed as close to the bypass chamber 10 as possible.
[00 08 ]
Then, the electric heater 13 is screwed from the rear end portion 20C of the heater mounting hole 21 toward the front end portion 20A. According to this, the side portion 13A of the electric heater 13 is the longitudinal axis Y- of the intake passage 2. Y is disposed substantially parallel to the fuel liquid level XX in the float chamber 6, and the distal end portion 13 </ b> B of the electric heater 13 is disposed facing the space portion Z. That is, the longitudinal axis AA of the electric heater 13 is disposed substantially parallel to the longitudinal axis YY of the intake passage 2 and the fuel liquid level XX.
[00 09 ]
According to the above, when the electric heater 13 is energized and the internal heat generating part generates heat, the heat is radiated from the side part 13A having a large heat generating area to the floating chamber body 5, and at this time, the side part 13A Is disposed along the longitudinal axis YY of the intake passage 2, the bypass chamber 10 including the bypass hole 11 can be effectively warmed, and the occurrence of icing can be suppressed.
Further, since the side portion 13A having the large heat generating area is arranged perpendicular to the storage direction (vertical direction) of the fuel level stored in the floating chamber 6, in other words, according to this, the floating chamber 6 It was possible to suppress the effect of warming the internal fuel, and thus to suppress fuel evaporation in the float chamber 6.
Further, since the electric heater 13 is disposed in the horizontal direction on the side, the energizing harness connected to the electric heater 13 also extends toward the right side. Since an intake pipe to the engine is connected and a space portion exists below this, the extension of the energizing harness to the right side does not cause any problems.
[00 10 ]
Further, by providing the space portion Z between the front end portion 13B of the heater mounting boss 20 and the side wall 5A of the floating chamber main body 5, it is possible to prevent the heat of the heater mounting boss 20 from being transmitted to the floating chamber main body 5. Therefore, fuel evaporation in the float chamber 6 is further effectively suppressed.
Furthermore, the presence of the space Z makes it possible to easily process the internal thread for the heater mounting hole 21 and to reliably remove chips from having no bag hole shape.
[00 11 ]
【The invention's effect】
As described above, according to the heater for preventing icing of the carburetor according to the present invention, the longitudinal axis of the electric heater is disposed substantially in parallel with the fuel liquid surface in the longitudinal axis direction of the intake passage. The bypass chamber can be effectively warmed by the side of the electric heater having a large heat generating area, thereby preventing icing.
Also, only the tip of the electric heater faces the fuel stored in the float chamber, and the side of the electric heater having a large heat generation area is not arranged along the fuel . And a space portion for heat insulation between the tip of the heater mounting boss and the float chamber main body, and the tip of the electric heater facing the space. According to this, it is possible to prevent the heat of the front end portion of the electric heater and the heater mounting boss from acting on the fuel in the float chamber, thereby suppressing the occurrence of fuel evaporation in the float chamber.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an embodiment of a heater for preventing icing of a vaporizer according to the present invention.
FIG. 2 is a longitudinal sectional view showing a conventional heater for preventing icing of a vaporizer.
[Explanation of symbols]
2 Intake passage 5 Float chamber body 5A Side wall 13 Electric heater 20 Heater mounting boss Z Space AA Long axis center line XX of electric heater Fuel liquid level YY Long axis center line of intake passage

Claims (1)

A carburetor body with an intake passage drilled laterally;
A throttle valve for opening and closing the intake passage;
A bypass hole that opens from the bypass chamber recessed along the longitudinal axis direction of the intake passage to the end of the throttle valve and opens into the intake passage;
In a carburetor comprising a float chamber in which a constant fuel liquid level is formed by a lower recess of the vaporizer body and a float chamber body disposed opposite thereto,
A heater mounting boss (20) is formed integrally with the float chamber body (5) and parallel to the longitudinal axis (YY) of the intake passage (2). ) Is formed between the side wall (5A) of the float chamber main body (5), and the longitudinal axis (A-A) of the electric heater (13) is formed on the heater mounting boss. Disposed in parallel with the longitudinal axis (YY) of the intake passage (2) and the fuel liquid level (X)-(X) formed in the float chamber (6) and the tip of the electric heater (13) A heater for preventing icing of a vaporizer, wherein (13B) is arranged facing the space (Z) .

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