JPH07317568A - Carburetor opening sensing device - Google Patents

Abstract

PURPOSE:To provide a carburetor opening sensing device which can work well with smaller size of construction through simplification of the sensing mechanism, allows suppression of the costs, and accomplishes enhancement of the sensing accuracy. CONSTITUTION:A carburetor is equipped with a carburetor body 2 having a venturi passage 6 and a valve chamber 7 formed in such a way as opening to the passage and a variable area valve 9 arranged in the valve chamber 7 slidably and varying the area of the venturi passage, and an opening sensing device is formed this carburetor by securing a magnet 25 to the valve 9. Magnetic sensors 28a-28c to emit the outputs in accordance with the intensity of the magnetic field generated by the magnet 25 are fixed directly to that position on the outer surface of a bulkhead 2d to form the valve chamber 7, which can be situated opposingly to the magnet 25.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an opening detecting device for detecting a throttle valve opening of a carburetor equipped with a direct acting throttle valve.

[0002]

2. Description of the Related Art For example, an engine of a motorcycle or the like is equipped with an ignition timing control device in order to improve output, fuel consumption and purify exhaust gas. The ignition timing control device is configured to detect the engine load state from the engine speed and the throttle opening, for example, and control the ignition timing to an ignition timing corresponding to these detected values.

In order to detect the throttle opening in such ignition timing control, when a carburetor having a rotary butterfly valve is conventionally provided, the rotation angle of the butterfly valve is detected by a potentiometer. The method is generally adopted. On the other hand, when the carburetor having a direct-acting piston valve is provided, the axial movement amount of the piston valve is converted into a rotation angle via a rotation mechanism, and this is detected by a potentiometer.

[0004]

However, in the above-described conventional opening degree detection device for the piston valve type carburetor, since it is necessary to separately provide a rotation mechanism for converting the movement amount of the piston valve into a rotation angle, the structure is required. However, there is a problem that the cost is increased due to the increase in the number of parts, and the detection accuracy is likely to be lowered due to the structure that converts the linear movement amount of the piston valve into the rotation angle. .

The present invention has been made in view of the above-mentioned conventional circumstances, and provides a carburetor opening degree detection device which can be downsized with a simple structure, can reduce cost, and can improve detection accuracy. It is an object.

[0006]

According to a first aspect of the present invention, there is provided a cab body having a venturi passage and a valve chamber formed so as to open into the passage, and a venturi passage slidably arranged in the valve chamber. In a carburetor opening detection device including an area variable valve for changing the area, a magnet is fixed to the area variable valve, and a magnetic sensor for generating an output according to the strength of a magnetic field from the magnet is used as the valve. It is characterized in that it is directly fixed at a position where it can face the magnet on the outer surface of the partition wall forming the chamber.

Here, in the present invention, directly fixing the magnetic sensor is not limited to the case where the magnetic sensor is directly fixed to the outer surface of the partition wall by soldering or the like, but the magnetic sensor is mounted on the substrate by soldering or the like, and the substrate is Also includes a case where the magnetic sensor is fixed so as to be in contact with the outer surface of the partition wall. As a method of fixing the board to the partition wall, for example, a method of forming a mounting bottom surface on the partition wall, positioning the board on the bottom surface with a knock pin or the like, and fixing the board with a push nut, a bolt or the like can be adopted. .

According to a second aspect of the present invention, a sensor chamber which is opened laterally is formed on the outer surface of the partition wall of the valve chamber, and a plurality of magnetic sensors are mounted at predetermined intervals in the sliding direction of the variable area valve. The substrate is fixed in the sensor chamber, and resin is filled in the sensor chamber.

According to a third aspect of the present invention, a sensor chamber that opens laterally is formed on the outer surface of the partition wall of the valve chamber, and a plurality of magnetic sensors are mounted at predetermined intervals in the sliding direction of the variable area valve. The substrate is fixed in the sensor chamber, and the opening of the sensor chamber is closed with a cap. The invention of claim 4 is characterized in that a communication passage is provided to connect the sensor chamber and the air vent passage. I am trying.

[0010]

In the opening degree detecting device of the present invention, the change in the magnetic field strength of the magnet due to the axial movement of the variable area valve is taken out as an electric signal by the magnetic sensor, and the opening degree of the variable area valve is calculated from the change in the electric signal. The ignition timing of the engine is controlled in accordance with the detected opening.

In the carburetor opening detection device according to the present invention, the detection mechanism is composed of the magnet fixed to the variable area valve and the magnetic sensor fixed to the outer surface of the partition wall of the cab body. The detection mechanism can be simplified as compared with the case where the device is provided, and eventually, downsizing can be supported, and the cost can be reduced by the number of parts.

Further, the magnetic sensor is directly fixed to the partition wall,
Since the position of the valve in the axial direction is directly detected, the detection accuracy can be improved as compared with the conventional device that converts the axial movement amount into the rotation angle. Further, since the magnetic sensor is directly fixed to the outer surface of the partition wall, the mounting position accuracy of the magnetic sensor itself can be improved, and the detection accuracy can be improved also from this point. By the way, when the magnetic sensor is once housed in the case and the case is fixed to the outer surface of the partition wall, an error in attaching the magnetic sensor to the case and an error in attaching the case to the partition wall occur.
As a result, there arises a problem that the error as a whole becomes large.

According to the second aspect of the present invention, the sensor chamber is formed on the outer surface of the partition wall, the substrate on which a plurality of magnetic sensors are mounted is fixed in the sensor chamber, and resin is filled to seal the magnetic sensor and the substrate with a resin. Since the magnetic sensor is stopped, it is possible to prevent the magnetic sensor from being damaged by an external force, improve the sealing property to ensure waterproofing and dustproofing, and improve the reliability of quality.

According to the third aspect of the present invention, since the opening of the sensor chamber of the partition wall is closed by the cap, the damage due to an external force can be prevented, the waterproof and dustproof properties can be improved, and the reliability of the quality can be improved. .

According to the fourth aspect of the present invention, since the communication passage that connects the sensor chamber closed by the cap and the air vent passage is provided, it is possible to prevent the sensor chamber from becoming negative pressure due to temperature change, and to prevent rainwater and the like. Intrusion can be prevented.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 5 are views for explaining a carburetor opening degree detection device according to an embodiment (first embodiment) of the invention of claims 1 and 2, and FIG. FIG. 2 is a sectional view of the vaporizer applied, FIG. 2 is a sectional view taken along line II-II of FIG. 1, FIG. 3 is a sectional view of the apparatus of the above embodiment, FIG. 4 is a sectional view taken along line IV-IV of FIG. 1, and FIG. It is a top view of an Example device.

In the figure, reference numeral 1 is a VM type vaporizer to which the apparatus of this embodiment is applied, and a float chamber 3 is bolted to an opening on the lower surface of a cab body 2 of the carburetor. Bypasses its venturi passageway 6. A wax type auto choke mechanism 4 for opening and closing the starter passage 6a is provided. A float 5 is vertically swingably arranged in the float chamber 3. The float 5 moves up and down in accordance with the change in the liquid level of the fuel in the chamber 3 to open and close a fuel introduction port (not shown), thereby keeping the liquid level of the fuel in the float chamber 3 constant.

The cab body 2 is made of zinc die-cast, and has a cylindrical main body 2a having a venturi passage 6 through which intake air (see mark a in FIG. 1) flows,
Cylinder portion 2b having a valve chamber 7 extending vertically upward from the main body portion 2a and opening into the venturi passage 6
And the body portion 2 so as to be coaxial with the cylinder portion 2b.
Fuel introduction part 2 extending from a into the float chamber 3
and c are integrally formed.

A lid 8 is attached to the upper end opening of the cylinder portion 2b, and a bottomed cylindrical piston valve 9 is axially slidably inserted into the valve chamber 7 of the cylinder portion 2b. There is. This piston valve 9 is made of brass or aluminum alloy, and a resin-made bottomed cylindrical holder 11 is fitted and inserted in the piston valve 9, and the space between the holder 11 and the lid 8 is A spring 10 for urging the valve 9 in the closing direction and pressing and fixing the holder 11 is provided.

The holder 11 has a piston valve 9
E-ring 21a for vertically positioning the jet needle 21 inserted into the above-mentioned fuel introduction portion 2c through the bottom of the
Is pressed against the bottom. Thereby, the holder 11
Is used both for holding the permanent magnet 25 described later and for holding the jet needle 21.

At the bottom of the piston valve 9, one end of a throttle cable 16 is locked, and the cable 16
The extended end of the guide passes through the guide pipe 17 connected to the lid 8 and is connected to an accelerator grip (not shown).
By operating the accelerator grip, the piston valve 9 is moved in the vertical direction to change the passage area of the venturi passage 6 between fully closed and fully opened.

A needle jet 20a is inserted in the upper portion of the fuel introducing portion 2c and opens below the piston valve 9 in the venturi passage 6.
Further, the main jet 20 is provided at the lower end of the fuel introducing section 2c.
b is screwed in and opens into the fuel. Within the needle jet 20a, the jet needle 2
1 is inserted so that the piston valve 9 can be moved forward and backward.
The jet needle 21 moves back and forth as the needle jet 20a moves up and down to change the effective opening area of the upper end opening of the needle jet 20a, thereby adjusting the amount of fuel sucked into the venturi passage 6.

A throttle screw 18 for adjusting the idling speed is screwed into a portion of the body portion 2a which faces the lower end portion of the piston valve 9, and the venturi passage 6 is lubricated in the upper portion thereof. An oil supply port 19 for supplying oil is connected and formed. The lubricating oil supplied from the oil supply port 19 flows down through the groove 9a formed on the side surface of the piston valve 9 and is supplied to the venturi passage 6. Further, an air vent passage 15 is formed in the cab body 2 to connect the space above the float chamber 3 and the outside (see FIG. 1), and the air vent passage 15 keeps the inside of the float chamber 3 at atmospheric pressure. It has become.

When viewed in the piston valve moving direction, the detection main part of the opening degree detecting device of this embodiment is orthogonal to the intake flow a flowing in the venturi passage 6 as shown in FIG. It is arranged on a straight line b passing through the center of 9. The main part of the detection is the permanent magnet 25 located at the upper edge of the piston valve 9, and the partition wall 2 of the cylinder part 2b.
It is composed of magnetic sensors 28a to 28c fixed to the outer surface of d.

The permanent magnet 25 is made of a plastic magnet, is formed integrally with the holder 11, and is exposed to the outside through a slit 9a formed at the upper edge of the piston valve 9. . Here, the outer end surface of the magnet 25 has a slight gap with respect to the inner surface of the partition wall 2d of the cylinder portion 2b. Further, the upper and lower edges of the permanent magnet 25 are formed with edge portions extending in a direction orthogonal to the sliding direction of the piston valve 9. As a result, the magnetic sensor 2 is prevented from diffusing the magnetic flux from the permanent magnet 25.
8a to 28c can be concentrated, and the detection position accuracy can be improved. The permanent magnet 25 may be directly insert-molded on the upper edge of the piston valve 9, or the permanent magnet 25 may be fixed to a metal holder and the holder may be insert-molded on the side wall of the piston valve.

On the outer surface of the partition wall 2d of the cylinder portion 2b, there is integrally formed a sensor chamber 30 which opens to the side, and the sensor unit 26 is accommodated in the sensor chamber 30. This sensor unit 26 has three magnetic sensors 28a, 28b, 28c on the inner surface of the substrate 27 on the partition wall 2d side.
Are fixed by soldering at a predetermined interval in the axial direction of the piston valve 9, and five lead wires 29 are attached to the outer surface of the substrate 27.
And the lead wires 29 corresponding to the magnetic sensors 28a to 28c are connected to the magnetic sensors 28a to 28c through wirings formed on the substrate 27 by patterning.
Each of the magnetic sensors 28a to 28c has a Hall element, MR.
An element or IC is used.

The base plate 27 of the sensor unit 26 has a positioning seat 31 in the sensor chamber 30, and a metal pin 32 press-fitted into the positioning seat 31 with a part thereof protruding into the sensor chamber 30 to form a positioning hole 27a in the base plate 27. It is fixed on the partition wall 2d in the sensor chamber 30 by inserting and fitting the push pin 33 into the metal pin 32.

As a result, the magnetic sensors 28a to 28c are in contact with the outer surface of the partition wall 2d of the cylinder portion 2b, and the permanent magnet 2 is moved as the piston valve 9 moves up and down.
5 and the partition wall 2d can be opposed to each other. In this case, when the throttle opening becomes the first opening slightly opened from the idling opening and the second and third openings opened further than the idling opening, the permanent magnet 25 causes the magnetic sensor 28 to move.
The positions of the sensors 28a to 28c are set so as to face the a to 28c.

Here, the permanent magnet 25 and the magnetic sensors 28a to 28c are arranged on the straight line b passing through the center of the piston valve 9 and orthogonal to the axis of the venturi passage 6, that is, the flow direction a of the intake air as described above. It is located in. This prevents the gap between the permanent magnet 25 and the magnetic sensors 28a to 28c from changing due to the vibration of the piston valve 9. That is, the piston valve 9 easily vibrates in the flow direction of intake air due to the influence of intake pulsation. Therefore, when the permanent magnet 25 and the magnetic sensors 28a to 28c are arranged on the axis of the venturi passage 6, that is, so as to face each other in the vibration direction, the gap between the two 25, 28a to 28c may change. The result detection accuracy may be reduced.

The mounting position of the base plate 27 in the axial direction of the piston valve is such that the permanent magnet 25 faces the magnetic sensor 28a at the lower end when the piston valve 9 reaches the first opening slightly raised from the idling position. Adjust to This is because in the state where the opening degree of the piston valve 9 is small, the intake amount largely changes due to a slight change in the opening degree of the piston valve 9, but does not change so much when the opening degree increases. Therefore, it is necessary to detect the small opening position of the piston valve 9 with higher accuracy, and by prioritizing the opposing of the permanent magnet 25 and the magnetic sensor 28a, the detection accuracy of the small opening position can be improved.

In order to further improve the detection position accuracy of the piston valve 9, the permanent magnet 25 and the magnetic sensor 2 are used.
It is desirable to make the change in the magnetic flux density steep with respect to the change in the distance from 8a to 28c. For that purpose, the permanent magnet 2
5 and the magnetic sensors 28a to 28c, the permanent magnet 25
It is advantageous to form a magnetic path composed of a magnetic plate or the like for concentrating the magnetic flux from the magnetic sensors 28a to 28c.

A resin sealing layer 35 is formed in the sensor chamber 30. This is formed by injecting and filling a potting agent made of a room temperature curing epoxy resin into the sensor chamber 30 and drying and solidifying the potting agent. As a result, the sensor unit 26 is resin-sealed, and the lead wires 29 project from the resin sealing layer 35.

The lead wires 29 are connected to a throttle opening discriminating circuit (not shown). This determination circuit is provided by the permanent magnet 25 associated with the axial movement of the piston valve 9.
When the magnetic field strength of the above is greater than or equal to a predetermined threshold value, it is determined that the axial position of the permanent magnet 25 coincides with any of the magnetic sensors 28a to 28c, and thereby the throttle opening is determined. There is.

Next, the function and effect of this embodiment will be described. According to the opening degree detecting device of the present embodiment, when the piston valve 9 rises from the idling position to the first opened degree slightly, the permanent magnet 25 faces the magnetic sensor 28a at the lower end, and the permanent magnet 25 moves from the magnetic sensor 28a. The output exceeds the predetermined threshold value, so that the throttle opening is determined to be the first opening. When the piston valve 9 further rises to the second and third opening degrees, the permanent magnet 25 sequentially faces the magnetic sensors 28b and 28c, and the magnetic sensor 2
The outputs from 8b and 28c exceed the threshold value, whereby the throttle opening is determined to be the second and third opening.

As described above, in this embodiment, the permanent magnet 25 is fixed to the upper edge of the piston valve 9, and each magnetic sensor 28a is fixed.
Since ~ 28c is fixed to the outer surface of the partition wall 2d of the cylinder portion 2b, the throttle opening of the piston valve 9 can be detected with a simple structure, and it is possible to reduce the size as compared with the case where a conventional rotation mechanism is separately provided. The cost of parts can be reduced.

Further, in this embodiment, the piston valve 9 is
Since the axial position of the piston valve is directly detected, the detection accuracy can be improved as compared with the conventional structure in which the axial movement amount of the piston valve is once converted into the rotation angle and the rotation angle is detected. Furthermore, in the present embodiment, each of the magnetic sensors 28a to 28a.
28c is mounted on the board 27, and the board 27 is attached to the metal pin 3
2. Since it is directly positioned and fixed to the partition wall 2d via the push nut 33, the mounting accuracy can be greatly improved as compared with the case of once accommodating it in a case or the like, and the detection accuracy can be improved also from this point.

Further, according to this embodiment, the sensor chamber 30 is formed on the outer surface of the partition wall 2d, and the resin sealing layer 35 is potted inside the sensor chamber 30 to seal the sensor unit 26 with the resin. It is possible to prevent damage and deformation due to, and to improve the sealing property to ensure waterproofing and dustproofing. Moreover, in this embodiment, since the resin sealing layer 35 is formed to be several times thicker than the sensor unit 26, the sealing property of the sensor chamber 30 can be further improved and the holding force of the lead wire 29 can be improved.

FIGS. 6 to 8 are views for explaining a carburetor opening detection device according to an embodiment of the invention of claims 3 and 4, wherein the same reference numerals as those in FIGS. 1 and 3 are used. Indicates the same or corresponding part.

The apparatus of the present embodiment is the same as the piston valve 9 described above.
The permanent magnet 25 is arranged and fixed on the upper edge of the cylinder portion 2
The sensor chamber 40 that opens laterally is integrally formed on the outer surface of the partition wall 2d of b, and the substrate 27 of the sensor unit 26 is directly positioned and fixed to the partition wall 2d in the sensor chamber 40. Is almost the same as that of the first embodiment.

A resin film is coated on the outer surface of the substrate 27 of the sensor unit 26. The lead wires 29 of the sensor unit 26 are connected to the sensor chamber 4
0 is led out downward from a notch 40a formed at the lower edge of the lead wire 0, and the lead wire 29 is provided in this notch 40a.
A seal member 43 that seals between and is attached.

A cap 41 for closing the sensor chamber 40 is attached to the opening of the sensor chamber 40. The cap 41 is fixed by fastening bolts 44 to bosses 40b formed at the left and right corners of the sensor chamber 40, and a gasket 42 is sealed between the opening of the sensor chamber 40 and the cap 41.

A communication hole 45 for communicating the inside of the sensor chamber 40 and the float chamber 3 is formed in the bottom of the sensor chamber 40, and the air vent passage 15 is opened in the upper portion of the float chamber 3. is doing. The communication hole 45 is formed by machining, and functions as a breather for adjusting the internal pressure of the sensor chamber 40 to atmospheric pressure. Further, the axis of the communication hole 45 is inclined downward from the sensor chamber 40 toward the chamber 3,
As a result, even if the fuel flows into the sensor chamber 40 from the float chamber 3 side, the fuel is supplied to the float chamber 3
Can be discharged into.

The operation and effect of this embodiment will be described. According to the apparatus of the present embodiment, the sensor chamber 40 is formed on the outer surface of the partition wall 2d of the cylinder portion 2b, and the sensor unit 26 is directly fixed in the sensor chamber 40. Therefore, it is possible to reduce the size with a simple structure and reduce the cost. Can be reduced and detection accuracy can be improved, and the same effect as that of the above-described embodiment can be obtained.

Further, in this embodiment, since the cap 41 for closing the opening of the sensor chamber 40 is fixed to the sensor chamber 40 by bolts, the sensor unit 26 can be prevented from being damaged by an external force and can be waterproof and dustproof. . Further, since the cap 41 is simply attached, the curing time for potting the above-mentioned resin can be eliminated, and workability and productivity can be improved accordingly.

Further, in the above embodiment, the sensor chamber 40
Since the inside and the air vent passage 15 are communicated with each other through the communication hole 45, it is possible to prevent the sensor chamber 40 from becoming negative pressure due to a temperature change, and it is possible to prevent water from entering due to negative pressure. Furthermore, since the communication hole 45 is inclined downward, the fuel can be discharged even when the fuel flows into the sensor chamber 40 at the time of a fall or the like.

In the above embodiment, the case where the communication hole 45 is formed by machining is taken as an example, but as shown in FIG. 9, the communication hole 46 is formed integrally with the cab body 2 by casting. The cost can be further reduced in this case. Further, in the above embodiment, the case where the communication hole is formed in the cab body to communicate with the air vent passage is taken as an example, but a tube or the like that opens to the atmosphere separate from the air vent is directly connected to the sensor chamber 40 and the breather You may add a function.

In the above embodiment, the case of application to the VM type vaporizer has been described as an example, but the present invention can be applied to the SU type vaporizer having a rotary butterfly valve.
In this case, a magnet is arranged in the piston valve that automatically moves up and down by the suction negative pressure.

[0048]

As described above, according to the opening degree detecting device of the carburetor according to the invention of claim 1, the magnet is fixed to the variable area valve, and the magnetic sensor is placed at a position where it can face the magnet on the outer surface of the partition wall. Since it is directly fixed, there is an effect that the size can be reduced with a simple structure, cost can be reduced, and detection accuracy can be improved.

According to the second aspect of the invention, the sensor chamber is formed on the outer surface of the partition wall, and the substrate on which the plurality of magnetic sensors are mounted is fixed and filled with resin in the sensor chamber. Since the opening of the sensor chamber is closed with a cap, damage and deformation due to external force can be avoided, and
It has the effect of improving the waterproof and dustproof properties.

According to the fourth aspect of the invention, since the sensor chamber closed by the cap and the air vent passage are communicated with each other by the communication passage, it is possible to prevent the sensor chamber from becoming negative pressure due to temperature change, and to prevent water from entering. There is.

[Brief description of drawings]

FIG. 1 is a side view for explaining an opening degree detecting device for a carburetor according to a first embodiment of the first and second aspects of the invention.

FIG. 2 is a sectional view of the device of the first embodiment.

FIG. 3 is a sectional view showing a detection portion of the device of the first embodiment.

FIG. 4 is a cross-sectional view showing a fixed state of the substrate of the apparatus of the first embodiment.

FIG. 5 is a plan view showing a detection portion of the apparatus of the first embodiment.

FIG. 6 is a side view showing an opening degree detecting device according to a second embodiment of the present invention.

FIG. 7 is a sectional view of the device of the second embodiment.

FIG. 8 is a cross-sectional view showing a communication hole of the second embodiment device.

FIG. 9 is a cross-sectional view showing a modified example of the communication hole portion of the second embodiment.

[Explanation of symbols]

 1 Vaporizer 2 Cab body 2d Partition wall 6 Venturi passage 7 Valve chamber 9 Piston valve (area variable valve) 15 Air vent passage 25 Permanent magnet 27 Substrate 28a-28c Magnetic sensor 30, 40 Sensor chamber 35 Resin 41 Cap 45, 46 Communication hole

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display area F02M 19/00 H

Claims (4)

[Claims] 1. A cab body having a venturi passage and a valve chamber formed so as to open to the passage, and an area variable valve slidably arranged in the valve chamber for changing a venturi passage area. In the carburetor opening detection device, a magnet is fixed to the variable area valve, and a magnetic sensor that generates an output according to the strength of the magnetic field from the magnet is used as the magnet on the outer surface of the partition wall that forms the valve chamber. An opening degree detection device for a carburetor, which is directly fixed to a facing position. 2. The sensor chamber according to claim 1, wherein a sensor chamber that opens laterally is formed on the outer surface of the partition wall of the valve chamber, and a plurality of magnetic sensors are mounted at predetermined intervals in the sliding direction of the variable area valve. An opening detecting device for a carburetor, wherein the substrate is fixed in the sensor chamber, and resin is filled in the sensor chamber. 3. The sensor chamber according to claim 1, wherein a sensor chamber that opens laterally is formed on the outer surface of the partition wall of the valve chamber, and a plurality of magnetic sensors are mounted at predetermined intervals in the sliding direction of the variable area valve. An opening detecting device for a carburetor, wherein the substrate is fixed in the sensor chamber, and the opening of the sensor chamber is closed by a cap. 4. The carburetor opening degree detection device according to claim 3, further comprising a communication passage that connects the sensor chamber and the air vent passage.