JP2003172209A - Starting device for carburetor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce installation space of a starting device by integrating two plunger type starting devices. <P>SOLUTION: This starting device 16 for a carburetor is provided with an air passage 20 communicating to the carburetor to supply starting air, a fuel passage 26 communicating to the carburetor to supply starting fuel, and a valve means including valve elements 36, 38 opening and closing the air passage and the fuel passage. The valve element communicates only the air passage 20 to the carburetor when the same is in a first state and communicates both of the air passage 20 and the fuel passage 26 to the carburetor when the same is in a second state. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carburetor starter, and more particularly to a plunger type starter.

[0002]

2. Description of the Related Art A carburetor is provided with a starter in order to start an engine easily. An example of a conventional carburetor starter is disclosed in Japanese Patent Laid-Open No. 2000-220525.
Is disclosed in. In this starting device, the starting fuel passage outlet is opened at the bottom of the starting valve chamber, the starting air passage outlet is opened at the side wall of the starting valve chamber, and the starting mixing passage is provided at another part of the side wall of the starting valve chamber. The air passage entrance is open. Each opening is opened and closed by a first plunger-type start valve provided in the start valve chamber. Further, there is provided a hot starting air passage that bypasses the starting valve chamber from the starting air passage and extends to the starting mixture passage. This hot starting air passage is opened and closed by a second plunger-type starting valve. The inlet for the starting fuel passage is connected to a portion below the constant fuel level in the float chamber, and the inlet for the starting air passage is connected to the atmosphere. The starting mixture passage outlet is connected to the intake pipe of the engine. The first start valve and the second start valve are separated from each other by a predetermined distance and are erected separately.

When the above-mentioned starting device is used, at the time of cold starting in a low engine atmosphere, the first starting valve is pulled upward, and the starting fuel passage, the starting air passage and the starting mixture passage are all opened. Become. The second start valve is not operated (not pulled up) and is held in the closed position. When a user of the engine performs a starting operation (kick or start of a starter motor), a negative pressure is generated in the intake pipe, and the negative pressure sucks the starting air and the starting fuel into the starting valve chamber. The air-fuel mixture generated in the starting valve chamber is sucked (supplied) to the intake passage through the starting air-fuel mixture passage, and cold start (combustion) of the engine is performed.

After the engine has been operated for a while, it is stopped,
Then, if the engine is restarted within a short period of time (for example, when the engine is stopped and restarted after traveling at high speed), the engine is already warmed up and hot. Such a restart is called a hot restart. At the time of hot restart, the first start valve is not pulled up and is held in the closed position to close the start fuel passage, the start air passage, and the start mixture passage. On the other hand, the second start valve is pulled up and moved to the open position to open the hot start passage. As a result, only the starting air is supplied to the intake passage. At the time of hot restart, the rich mixture already exists in the intake pipe, so
This is because it is sufficient to supply the starting air without supplying the starting fuel. The supplied starting air dilutes the rich air-fuel mixture to form an air-fuel mixture having an appropriate mixing ratio. Therefore, the hot restart can be smoothly performed.

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In 220225, a plunger type starting device for cold starting and a starting device for plunger type hot restart are provided as separate starting devices. That is, two plunger type starters are required. A large installation space is required to provide two starters.

An object of the present invention is to solve the above problems of the prior art.

[0007]

According to the present invention, an air passage communicating with a carburetor for supplying starting air, a fuel passage communicating with the carburetor for supplying starting fuel, and the air. A starting device for a carburetor, comprising: a valve means including a valve body that opens and closes a passage and the fuel passage, wherein the valve body comprises:
When in the first state, only the air passage communicates with the carburetor, and when in the second state, both the air passage and the fuel passage communicate with the carburetor. A device is provided. With one valve means, it is possible to connect only the air passage to the carburetor, and to connect both the air passage and the fuel passage to the carburetor.

A plunger, which is connected to the valve body and can be selectively moved to the first and second stage positions in the axial direction of the valve body, may be further provided. When the plunger is moved to the first stage position, the valve body is in the first state. Further, when the plunger is moved to the second stage position, the valve body is in the second state. A holding mechanism for holding the plunger at the one-step position or the two-step position may be further provided.

The valve element may include an air valve member and a fuel valve member arranged in a nested structure. When the plunger moves to the one-step position, only the air valve member moves in the plunger axial direction to connect only the air passage to the carburetor. When the plunger moves to the second stage position, the air valve member and the fuel valve member move in the axial direction of the plunger to connect both the air passage and the fuel passage to the carburetor.

[0010]

Embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 5 is a front view of the carburetor for a motorcycle, in which an intake passage 10 having a circular cross section is provided in the center. The intake air flows in the intake passage from the front side of the paper to the other side. A float chamber 14 is attached to the bottom of the carburetor body 12. A predetermined amount of fuel is stored in the floating chamber 14. Vaporizer body 1
A carburetor starter main body 16a is provided on the left side of 2. Reference numeral 18 is a knob of the starting device, and reference numeral 20a is an inlet (upstream end) of the starting air passage 20.

FIG. 6 is a sectional view taken along line 6-6 of FIG. The intake air flows from right to left in the figure. A throttle valve 22 is provided at the center of the intake passage 10. Reference numeral 24 is a starter jet. 7 is a sectional view taken along line 7-7 of FIG. As in FIG. 6, intake air flows from right to left in the figure. The starting air passage 20 is arranged so as to bypass the throttle valve 22.
Branch from the intake passage 10 and extend along the intake passage 10. The downstream end (outlet) of the starting air passage 20 merges with the downstream end (outlet) 26 a of the starting fuel passage 26. The starting fuel passage 26 extends upward from below in the direction perpendicular to the plane of the drawing. From the confluence of the starting air passage 20 and the starting fuel passage 26, a starting mixture passage 28 extends toward the intake passage 10. Reference numeral 30 is a plunger hole of the starting device. The plunger hole 30 extends in the direction perpendicular to the plane of the drawing and accommodates a plunger (described later) slidably.

FIG. 8 is a schematic sectional view taken along line 8-8 of FIG.
It is sectional drawing when the vaporizer shown in FIG. 5 is cut | disconnected by the surface containing the center line of the plunger hole 30. The fuel 34 stored in the float chamber 14 passes through the starter jet 24 and is sucked upward, and reaches the lower end of the plunger hole 30 through the fuel passage 26. The plunger housed in the plunger hole 30 is omitted.

FIG. 1 is a sectional view of the starting device 16, which is in a non-operating state (initial state, fully closed state). The illustrated starting device 16 is a plunger type starting device and is of a push-push type. The starter body 16a has a start valve chamber 32 and a plunger hole 30 which extend vertically in the interior thereof. Both the starting valve chamber 32 and the plunger hole 30 are cylindrical. The plunger hole 30 is formed above the starting valve chamber 32. An outlet 26a of the fuel passage 26 for transferring the starting fuel from the float chamber 14 to the starting valve chamber 32 is opened at the bottom of the starting valve chamber 32.
The inlet of the fuel passage 26 opens below the liquid surface of the fuel in the float chamber 14. On the right side wall of the starting valve chamber 32, the starting valve chamber 32
The outlet of the air passage 20 for transferring the starting air is opened. The inlet of the air passage 20 opens (communicates) with the atmosphere or the air cleaner chamber via the intake passage 10.
The starting fuel and the starting air that have entered the starting valve chamber 32 are mixed to form a starting mixture. On the left side wall of the starting valve chamber 32, an inlet of a mixture passage 28 for transferring the starting mixture from the starting valve chamber 32 to the downstream of the intake passage 10 is opened.

As shown in FIG. 1, an air valve member 36 and a fuel valve member 3 are provided in the starting valve chamber 32 and the plunger hole 30, respectively.
8 are arranged in a telescopic structure. Figure 1
And as can be seen from FIG. 4, a cylindrical air valve member 36.
Is located outside the cylindrical fuel valve member 38 and is slidably provided with respect to the fuel valve member 38. The air valve member 36 and the fuel valve member 38 are collectively referred to as a valve body. The air valve member 36 is movable upward in the starting valve chamber 32 and the plunger hole 30. In the state of FIG. 1, the air valve member 36 and the fuel valve member 38 are in the initial position (closed position). It can be said that the valve body is also in the initial state. The air valve member 36 closes the outlet of the starting air passage 20 and closes the inlet of the mixture passage 28. The fuel valve member 38 closes the outlet of the starting fuel passage 26. A rubber sheet 40 is provided at the lower end of the fuel valve member 38, and the rubber sheet 40 blocks the outlet of the starting fuel passage 26.

A plunger 42 is provided on the air valve member 36.
Are provided integrally. Therefore, the air valve member 36
And the plunger 42 move integrally. The plunger 42 is slidable in the plunger hole 30 in the axial direction of the plunger 42. The plunger 42 has a small diameter portion 42a below the stem of the knob 18. As shown in FIG.
The plunger 42 has a small diameter portion 42a,
First large diameter portion 42b, first notch (V-shaped groove, notch portion) 42
c, the second large diameter portion 42d, the second notch 42e, and the third large diameter portion 42f.

A plunger cap 44 is provided on the upper end of the carburetor body 12, and in the state of FIG. 1, the plunger cap 44 is located around the small diameter portion 42a and the first large diameter portion 42b of the plunger. Plunger cap 44
A rubber cap 46 is fitted from above. A snap ring 48 is provided on the outer periphery of the upper portion of the plunger cap 44. As shown in FIG. 9, the snap ring 48 has a substantially C-shape including a linear portion 48a, and in the state of FIG. 1, the linear portion 48a is in contact with the small diameter portion 42a of the plunger 42. Absent. Therefore, plunger 4
There is little radial inward force against the axial movement of the plunger. Therefore, when the user pulls up the plunger 42, the user feels almost no response (resistance) for a while. Then, the first large diameter portion 42b of the plunger 42
Comes into contact with the straight portion 48a of the snap ring 42,
Since the straight line portion 48a is widened by the first large diameter portion 42b (broken line in FIG. 9), the snap ring 48 is fixed to the plunger 4
A diametrically inward biasing force is applied to 2. When the plunger 42 is further pulled up, the first notch 42 of the plunger 42
c and the linear portion 48a of the snap ring 48 are engaged (FIG. 3). This state is the first stage position of the plunger 42. In this state, the snap ring straight portion 48a is the first
Since it is captured by the notch 42c, when the plunger 42 is moved further upward, the first notch 42c tries to regulate the movement of the plunger 42, and the user feels a sense of response. Further, even if the user releases the plunger 42 in this state, the first notch 42c and the snap ring linear portion 4
Due to the engagement with 8a, the plunger 42 does not move downward (return). Therefore, the plunger 42 is held at the first stage position. When the plunger 42 is pulled up with a relatively large force, the engagement between the plunger first notch 42c and the snap ring linear portion 48a is released, and the plunger 42
The second large diameter portion 42d and the snap ring straight portion 48a come into contact with each other. When the plunger 42 is further pulled up, the second notch 42e of the plunger 42 engages with the snap ring linear portion 48a (FIG. 2). This state is the second stage position of the plunger 42. Even if the user releases the plunger 42 in this state, the plunger 42 does not move downward (return) due to the engagement between the second notch 42e and the snap ring linear portion 48a. Therefore, the plunger 42 is held at the second stage position.

A rubber cap 46 is provided on the top of the plunger 42.
Protruding from. By pulling up the knob 18 attached to the top of the plunger 42, the plunger 42 can be moved upward in the plunger hole 30. When the plunger 42 is moved upward, the air valve member 36 is also moved upward. A plunger return spring 50 is provided on the outer periphery of the lower portion of the plunger, and urges the plunger 42 downward. In the illustrated structure, the plunger return spring 50 pushes the air valve member 36 downward. However, since the plunger 42 and the air valve member 36 are integrated, the plunger 42 is pushed downward. The state where the starter 16 is not operated (state of FIG. 1)
Then, the plunger return spring 50 forces the plunger 42 and the pneumatic valve member 36 to the illustrated initial positions.

A seat spring 52 is provided between the air valve member 36 and the fuel valve member 38. The seat spring 52 biases the air valve member 36 upward and biases the fuel valve member 38 downward. In the state shown in FIG. 1, the air valve member 36 has the plunger return spring 50.
Is forced to the initial position (closed position), and the fuel valve member 38 is forced to the initial position (closed position) by the seat spring 52. Plunger return spring 50
Is set to be larger (stronger) than the load of the seat spring 52.

Next, a case where the starting device 16 is used to start the engine will be described. In the present specification, the engine start when the engine atmosphere temperature is low is called a cold start, and the engine start when the engine atmosphere temperature is high is called a hot start. The hot start refers to, for example, a case where the engine is stopped after the engine has been warmed up (including after traveling), and the engine is restarted after a short time.

At the time of cold start, as shown in FIG. 2, the plunger 42 is pulled up by two stages from the state of FIG. 1 and is positioned at the second stage position. The second stage position is the full pull position of the plunger 42. The plunger 42 is pulled up manually by picking the knob 18. Plunger 42 second
When moved to the step position, both the air valve member 36 and the fuel valve member 38 are pulled up, and the air passage 20 and the fuel passage 2
6 and the mixture passage 28 are opened. Both the starting air passage 20 and the starting fuel passage 26 are in communication with the carburetor. That is, the valve body is in the "second state" referred to in the claims.
It is in. When the engine starting operation (kick or starting of the starter motor) is performed here, negative pressure is generated in the intake passage 10,
This negative pressure acts on the valve chamber 32 through the mixture passage 28. Therefore, the starting air is sucked from the atmosphere into the valve chamber 32 through the air passage 20, and the starting fuel is sucked from the float chamber 14 through the fuel passage 26 into the valve chamber 32. as a result,
The starting air and the starting fuel are mixed in the valve chamber 32, and an air-fuel mixture is generated. The air-fuel mixture generated in the valve chamber 32 is sucked (supplied) to the intake passage 10 through the air-fuel mixture passage 28. The engine is smoothly started by this starting mixture.

At the time of hot start, as shown in FIG. 3, the plunger 42 is pulled up one step from the state of FIG. 1 and is positioned at the first step position. When the plunger 42 is pulled up one step from the state of FIG. 3, the state of FIG. 2 is obtained. As shown in FIG. 3, when the plunger 42 is moved to the first stage position, only the air valve member 36 is pulled up, and the air passage 20 and the air-fuel mixture passage 28 are opened. Fuel valve member 3
Since 8 is held in the initial position, the fuel passage 26 remains closed. Only the starting air passage 20 is in communication with the intake passage 10 (carburetor). That is, the valve body is in the "first state" referred to in the claims.

When the plunger 42 is moved upward by a predetermined distance from the first step position, the inwardly extending portion (hook portion) 36a at the lower end of the air valve member 36 is expanded by the enlarged diameter portion 38a of the fuel valve member 38. Engage with. When the plunger 42 is further moved upward, the air valve member 36 pulls up the fuel valve member 38. That is, when the plunger 42 is pulled up from the first stage position by a predetermined distance and then further pulled up, the air valve member 36 and the fuel valve member 38 are integrally moved upward. The air valve member 36 and the fuel valve member 38 move integrally until the plunger 42 is lifted to the uppermost position (second stage position).

In the hot start of the engine, the engine is in a sufficiently warmed-up state, and the atmosphere inside the carburetor is already in a rich (fuel rich) state or a rich state.
If the starting air-fuel mixture is further supplied to the (over) rich atmosphere, the engine will not be started smoothly. Therefore, only the starting air is supplied to the carburetor. When the operation of starting the air-fuel mixture (kick or start of the starter motor) is performed, a negative pressure is generated in the intake passage 10, and the starting air is supplied to the intake passage 10 through the valve chamber 32. As a result, the already existing rich air-fuel mixture is appropriately diluted by the starting air, and an air-fuel ratio suitable for hot starting is obtained in the carburetor. Therefore, the engine can be started smoothly.

According to the above embodiment, one plunger type starting device can cope with cold starting and hot starting. Therefore, as compared with the structure in which the two plunger type starting devices are separately provided, the installation space of the starting device can be reduced. Although the plunger 42 is moved to the first stage position or the second stage position according to the ambient temperature of the engine in the above embodiment, the plunger 42 is moved to the first stage position or the second stage position according to the mixture concentration in the intake passage 10. You may move to a 1st step position or a 2nd step position. For example, after a motorcycle has fallen and the engine has stopped, when the driver raises the motorcycle and then restarts the engine, the driver typically turns the grip to open the throttle. as a result,
Fuel flows from the acceleration pump into the intake passage 10,
The air-fuel mixture inside becomes (over) rich. Therefore, the plunger 42 is moved to the first stage movement so that only the starting air is supplied to the intake passage 10 to thin the air-fuel mixture in the (excessive) rich state and obtain a good engine start.

The plunger 42 was pulled up manually, but a cold start switch, a hot start switch, etc. were provided.
The plunger 42 may be pulled up automatically. Further, although the plunger 42 is pulled up by picking up the knob 18, it may be pulled up through a wire or a lever. An example using a lever is shown in FIG. As shown in FIG. 10, a lever 54 is provided near the upper portion of the plunger 42.
A leaf spring 56 extends from the support member 55 of the lever 54. The leaf spring 56 has two corrugations (projections) 56a at its tip (right end in the figure). Tip projection 5 of lever 54
4a engages with the knob 18 of the plunger 42, and the lower end protrusion 54b engages with the corrugated portion 56a of the leaf spring 56. When the lever grip portion 54d is operated, the lever 54 turns around the central portion 54c. The state of FIG. 10 is a state in which the plunger is not pulled up at all. When the lever 54 is operated from the state shown in FIG. 10, the plunger 42 is held at the first step position and the second step position by the engagement between the lower end protrusion 54d of the plunger 42 and the corrugated portion 56a.

In the example of FIG. 10, the lever 42 and the leaf spring 56 hold the plunger 42 at the initial position, the first step position and the second step position. Therefore, the plunger 42 is shown in FIGS. It is not necessary to have such a small diameter portion 42a, the first notch 42c, and the second notch 42e. Further, it is not necessary to provide the snap ring 48. Further, in the above embodiment, the plunger 42 is pulled up so that only the air passage 20 or the air passage 20 and the fuel passage 26 are provided.
Although the structure for opening both sides has been described, only the air passage 20 or the air passage 20 can be obtained by rotating the plunger.
Both the fuel passage 26 and the fuel passage 26 may be opened. For example, when the knob of the plunger 42 is rotated 90 degrees, the plunger 42 is moved to the first predetermined position to open only the air passage 20, and when it is further rotated 90 degrees, the plunger 42 is rotated.
May be moved to the second predetermined position to open the air passage and the fuel passage. Alternatively, when the knob of the plunger 42 is rotated 90 degrees, the plunger 42 opens only the air passage 20, and when the plunger 42 is pulled up from there, the plunger 42 may open both the air passage 20 and the fuel passage 26. . Further, a structure may be adopted in which the plunger 42 is pushed down in two steps to open only the air passage 20 and open both the air passage 20 and the fuel passage 26.

Although a carburetor for a motorcycle has been described in the above embodiment, the starting device of the present invention is a snowmobile or an ATV.
It can also be applied to vaporizers such as (All Terrain Vehicle). Further, although the pull-push type (two-stage pull type) plunger has been described, a stepless type plunger can also be adopted. The stepless type plunger can open the air passage 20 from 0% opening to 100% opening. When using a stepless type plunger, move the plunger to the first stage position and / or the second stage position.
The mechanism for holding the stepped position may not be provided.

Cold start may also be referred to as cold start and hot start may be referred to as hot start or hot restart.

[0029]

The installation space for the starting device can be reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a starting device according to an embodiment of the present invention, showing a state where the starting device is not used (fully closed state).

FIG. 2 is a sectional view similar to FIG. 1, but showing the case where the plunger of the starting device is moved to the second stage position.

FIG. 3 is a sectional view similar to FIG. 1, but showing the case where the plunger of the starting device is moved to the first stage position.

4 is an exploded perspective view of the valve body shown in FIG. 1. FIG.

FIG. 5 is a front view of a carburetor for a motorcycle.

6 is a sectional view taken along line 6-6 of FIG.

7 is a sectional view taken along line 7-7 of FIG.

8 is a sectional view taken along line 8-8 of FIG.

9 is a plan view of the snap ring shown in FIG. 1. FIG.

FIG. 10 is a side view showing another example of the plunger holding mechanism.

[Explanation of symbols]

10 Intake passage 12 Vaporizer body 16 Starter 20 air passages 26 Fuel passage 28 air-fuel mixture passage 36 Air valve member 38 Fuel valve member 42 Plunger 54 lever 56 leaf spring

Claims (4)

[Claims] 1. An air passage communicating with a carburetor for supplying starting air, a fuel passage communicating with the carburetor for supplying starting fuel, and a valve for opening / closing the air passage and the fuel passage. And a valve means including a body, wherein the valve body communicates only the air passage to the carburetor when in the first state and when in the second state. A carburetor starting device, characterized in that both the air passage and the fuel passage are communicated with the carburetor. 2. A plunger connected to the valve body and capable of being selectively positioned at first and second step positions in the plunger axial direction, wherein the plunger is positioned at the first step position,
The valve body is in the first state and the plunger is in the second state.
The carburetor starter according to claim 1, wherein the valve body is brought into the second state when positioned in the stepped position. 3. The plunger is set to the one-stage position or two.
The carburetor starter according to claim 2, further comprising a holding mechanism for holding the carburetor in a stepped position. 4. The valve body comprises an air valve member and a fuel valve member arranged in a nested structure, and when the plunger moves to the one-step position, only the air valve member moves in the plunger axial direction. When the plunger is moved to connect only the air passage to the carburetor, and the plunger is moved to the second stage position, the air valve member and the fuel valve member move in the plunger axial direction to move the air passage and the fuel. 3. Both of the passages are connected to the carburetor.
Alternatively, the carburetor starter according to the above item 3.