JPH036844Y2 - - Google Patents

Description

[Detailed explanation of the invention] A. Purpose of the invention (1) Industrial application field The present invention is a starting fuel adjustment device for a carburetor, in particular, a starting fuel adjustment device provided in the carburetor body in the middle of the starting intake passage. A starting fuel nozzle facing the intake passage and communicating with the float chamber is disposed, and a sliding hole is provided that opens an inlet connected to the upstream side of the starting intake passage and an outlet connected to the downstream side of the starting intake passage to the inner side. A sliding throttle valve is slidably connected to the sliding hole, and the inflow port is connected from a fully closed state when the ambient temperature is high to a fully open state when the ambient temperature is low. The present invention also relates to a starting fuel adjustment device for a carburetor, in which the sliding throttle valve is connected to a temperature-sensitive drive means that operates according to the ambient temperature in order to control the opening area of the outlet.

(2) Prior Art Conventionally, in such a starting fuel adjusting device, the shape of the inlet and the outlet are generally circular.

(3) Problems to be solved by the invention In the conventional structure described above, the opening areas of the inlet and the outlet change almost proportionally depending on the ambient temperature. However, according to the inventor's experiments, when the ambient temperature exceeds a predetermined value within the range of 25 to 39 degrees Celsius, for example 37 degrees Celsius, the concentration of the starting air-fuel mixture tends to increase suddenly. The engine installed in the engine had a problem with startability after being left unused for a long time in hot weather.

The present invention was proposed in view of such circumstances, and improves starting performance by making the mixture concentration thinner than before when the ambient temperature is higher than a predetermined value within the range of 25 to 39 degrees Celsius. An object of the present invention is to provide a starting fuel regulating device for a carburetor.

B. Structure of the invention (1) Means for solving the problem In order to achieve the above object, according to the invention, in the starting fuel regulating device for a carburetor of the type described above, the inlet and the outlet have an ambient temperature of 25 a first opening that is controlled to open and close by a sliding throttle valve when the temperature is lower than a predetermined value in the range of ~39°C, and is fully closed when the temperature is higher than the predetermined value; and a second opening which is controlled to open and close by a sliding throttle valve when the ambient temperature is higher than the predetermined value, and is fully open when the ambient temperature is lower than the predetermined value, and the second opening The first opening is wider than the first opening in the direction perpendicular to the sliding direction of the sliding throttle valve, and the boundary between the two openings has a sliding opening when the ambient temperature is at the predetermined value. A step is formed corresponding to the operating position of the throttle valve.

(2) Effect When the ambient temperature is higher than a predetermined value within the range of 25 to 39°C, the opening area of the inlet and outlet becomes particularly larger than that of the conventional one. In this case, the air-fuel mixture can be sufficiently diluted by increasing the intake air flow rate significantly.

(3) Example An example in which the present invention is applied to a motorcycle carburetor will be explained below with reference to drawings.
First, in FIG. 1, a starting fuel adjusting device 2 is attached to a carburetor 1 mounted on a motorcycle. The fuel mixture is configured to supply a mixture for use.

In FIGS. 2 and 3, the carburetor 1 includes a float chamber body 6 for defining a float chamber 5 between the carburetor body 4 and the carburetor body 4, which has an intake passage 3 therein. Constructed by combining. The carburetor main body 4 and the float chamber body 6 are each formed by die-casting of aluminum, for example.

The carburetor main body 4 includes an intake path 3 along the intake direction 7.
A starting air intake path 8 for quickly rotating the air intake path 3 is formed by connecting the upstream end and the downstream end of the engine, and a starting fuel adjustment device 2 is disposed in the middle of the starting air intake path 8. . That is, the starting intake passage 8 includes an upstream part 8a that is bored from the upstream end to communicate with the upstream end of the intake passage 3, and a downstream part 8a that is bored from the downstream end to communicate with the downstream end of the intake passage 3. 8b are connected to each other via the starting fuel adjusting device 2.

The starting fuel adjustment device 2 includes a starting fuel nozzle 9 facing the intermediate part of the starting intake passage 8, that is, a connection part between the upstream and downstream parts 8a and 8b, and a starting fuel nozzle 9 for adjusting the opening area of the starting intake passage 8. Sliding throttle valve 10
and a metering needle valve 11 held by the sliding throttle valve 10 and inserted into the starting fuel nozzle 9.

The sliding throttle valve 10 is slidably fitted into a sliding hole 12a provided in a sleeve 12 which is basically a cylinder with a bottom. It is fitted into a hole 13 bored in the carburetor main body 4 perpendicularly to those portions 8a, 8b so as to be connected to the end portions of the carburetor body 4. Moreover, the upper end of the sleeve 12 has a hole 13.
The claws 14 bent inward from the inner surface of the sleeve 12 are caulked, thereby fixing the sleeve 12 to the carburetor main body 4. A starting fuel nozzle 9 is press-fitted and fixed to the closed end, that is, the lower end of the sleeve 12, with the regulating cylindrical portion 9a at the upper end thereof protruding upward. It is thrust into the starting fuel chamber 15 defined between the bodies 6. Moreover, the lower part of the starting fuel chamber 15,
A fuel jet 16 is disposed between the float chamber 5 and a portion below the fuel oil level.

4 and 5, the sleeve 12 has an inlet 17 communicating with the upstream portion 8a of the starting intake passage 8 and an outlet 18 communicating with the downstream portion 8b. Drilled on the diameter line. Furthermore, the inlet 17 and the outlet 18 are provided on the inner surface of the side wall of the sleeve 12 to open into the sliding hole 12a, and the outer surface of the side wall of the sleeve 12 is provided with an inlet-side recess 19 communicating with the inlet 17 and a flow-through hole 12a. Exit 18
An outflow side recess 20 communicating with is provided.

The sliding throttle valve 10 is slidably driven according to the ambient temperature, and as shown in FIG. The shape of is determined.
That is, the scale shown on the right side of FIG. 6 indicates the position of the lower edge of the sliding throttle valve 10 corresponding to the temperature. The inlet 17 and the outlet 18 are controlled to open and close by the sliding throttle valve 10 when the ambient temperature is lower than a predetermined value (25°C in the illustrated example) within the range of 25 to 39°C. The first openings 17b and 18b are fully closed when the temperature is higher than the predetermined value.
A second opening is connected to the first openings 17b and 18b and is controlled to open and close by the sliding throttle valve 10 when the ambient temperature is higher than the predetermined value, and is fully open when the ambient temperature is lower than the predetermined value. Opening 17
a, 18a, especially the first opening 1
7b and 18b have an upwardly convex semicircular shape, and a second
Since the openings 17a and 18a are each formed in an oval shape that is elongated in the circumferential direction of the sliding hole 12a, the second openings 17a and 18a are closer to the sliding throttle valve than the first openings 17b and 18b. It is formed wide in the direction orthogonal to the sliding direction. Further, at each boundary between the openings 17a, 17b; 18a, 18b, there is provided a sliding throttle valve 1 when the ambient temperature is at the predetermined value.
Steps 17e and 18e correspond to the position of the lower edge of 0.
is formed.

Since the shapes of the inlet 17 and the outlet 18 are determined in this way, the inlet 17 and the outlet 18 can be arranged when the ambient temperature is higher than a predetermined value within the range of 25 to 39°C (25°C in the illustrated example). The opening area of the outflow port 18 can be made especially larger than that of the conventional substantially circular inlet and outflow ports, and as a result, the intake air flow rate (see the solid line in FIG. ) is significantly larger than that of the conventional example (see the dotted line in Figure 7), which can effectively prevent the mixture from becoming over-enriched and contribute to improving engine startability in hot weather. . Note that the opening areas of the inlet 17 and the outlet 18 when fully opened are set to be approximately the same as those of the conventional type shown by the chain lines.

The inflow side and outflow side recesses 19 and 20 are configured to allow a slight misalignment between the opening ends of the upstream and downstream portions 8a and 8b of the starting air intake path 8 and the inflow port 17 and the outflow port 18. It is formed larger than the inlet 17 and outlet 18. In particular, in the inlet side recess 19, the inlet 17 and the outlet 18 are provided in a straight line even though the upstream part 8a and the downstream part 8b of the starting intake passage 8 are at an angle with each other. It is provided long along the circumferential direction of the sleeve 12 to communicate the inlet 17 with the upstream portion 8a.

The sliding throttle valve 10 is basically formed in a cylindrical shape, and an E-type retaining ring engaged with the upper end of the metering needle valve 11 is retained on the inner surface of the sliding throttle valve 10 near the lower end. A support plate 21 of E is provided.
By pressing the retaining ring onto the support plate 21 by means of the spring 22, the metering needle valve 11 becomes the sliding throttle valve 10.
is maintained. Further, a locking collar 23 is provided at the upper end of the sliding throttle valve 10 and projects radially inward, and this locking collar 23 includes a temperature-sensitive drive means 24 for driving the sliding throttle valve 10. An engaging protrusion 26 provided at the lower end of the set collar 25 constituting the set collar 25 can be engaged from below. Moreover, the spring 22 is interposed between the set collar 25 and the support plate 21.

Referring again to FIG. 1, the temperature sensing drive means 24 includes a temperature sensor 28 equipped with a piston 27 that expands and contracts depending on the temperature, and a temperature sensor 28 that is integrally provided with the temperature sensor 28.
It comprises a PTC type heater 29, a set collar 25 with which the piston 27 comes into contact, a wax collar 30 that guides the movement of the set collar 25, and a spring 31 interposed between the set collar 25 and the wax collar 30.

Wax is built into the thermosensor 28,
When this wax expands in accordance with the rise in temperature, the piston 27 is actuated to extend. The wax collar 30 is fitted into the upper part of the hole 13 via the sealing member 32 so that its lower end is in contact with the upper end of the sleeve 12, and is fixed to the vaporizer main body 4. The wax color 30 is basically formed in a cylindrical shape, and inside this wax color 30,
A set collar 25 is housed so as to be movable in the axial direction. Moreover, the set collar 25 consists of a bottomed cylindrical part 33 with an open upper part, and a small diameter cylindrical part 34 concentrically connected to the lower end of the bottomed cylindrical part 33. It is formed to have an outer diameter that can be inserted into the body. This small diameter cylindrical part 34
The engaging protrusion 26 is provided at the lower end.

The lower part of the temperature sensor 28 is inserted into the bottomed cylindrical part 33 of the set collar 25, and the piston 27
protrudes from the lower part of the temperature sensor 28 to come into contact with the bottomed cylindrical portion 33 . Furthermore, the set collar 25 is biased toward the temperature sensor 28 by the spring force of the spring 31, and the piston 27 is moved toward the bottomed cylindrical portion 3.
Always in contact with the bottom of 3.

The temperature sensor 28 is inserted into the wax holder 36 by screwing the upper part of the wax collar 30 into the wax holder 36 made of synthetic resin, and a spring 35 is inserted between the temperature sensor 28 and the wax holder 36.
is interposed. Thereby, the temperature sensor 28 is elastically supported by the wax holder 36, that is, the vaporizer main body 4.

Inside the wax holder 36, a pair of terminals 37,
38 is buried, and these terminals 37, 38
are in contact with both ends of the PTC type heater 29, respectively.

One of the terminals 37 is connected to an intermediate portion of the charging generating coil 40 in the alternator 39, and the other terminal 38 is grounded. AC generator 39
The ignition generating coil 41 is connected to an ignition device 42, and this ignition device 42 is connected to a battery 45 via a main switch 43 and a fuse 44. The charging generator coil 40 also has a diode 4 connected to the connection point between the main switch 43 and the fuse 44 in order to charge the battery 45.
6.

Next, to explain the operation of this embodiment, when the engine is started, the wax in the temperature sensor 28 is in an expanded state corresponding to the ambient temperature, so the amount of protrusion of the piston 27 from the temperature sensor 28 is also at the ambient temperature. The opening degree of the sliding throttle valve 10 also corresponds to the ambient temperature via the set collar 25.

Main switch 43 to start the engine
When the ignition device 42 is turned on and cranked to enable operation, an amount of air corresponding to the opening degree of the sliding throttle valve 10 flows into the sleeve 12 from the inlet 17, and the flow of this air causes the engine to start. A mixture is formed by the fuel sucked out from the fuel nozzle 9 and the air, and the mixture is supplied to the engine,
It operates together with the engine alternator 39.

When the alternating current generator 39 operates, the PTC type heater 29 is also energized, and the wax expands due to the heat generated by the heater 29. Therefore, the piston 27
expands, and the set collar 25 is pressed downward. This downward movement of the set collar 25 causes the spring 22 to
The sliding throttle valve 10 is pushed downward via the inlet 17 and the outlet 18 are shut off. The sliding throttle valve 10 opens the starting fuel nozzle 9 from its shut-off state.
Further downward movement is allowed until it abuts against the regulating cylindrical portion 9a at the upper end, and after the sliding throttle valve 10 reaches the lowest position, the piston 27 expands due to the expansion of the wax. The set collar 25 moves downward relative to the sliding throttle valve 10 while compressing the spring 22.

Moreover, the higher the temperature of the PTC type heater 29,
Since the resistance value increases, after the temperature reaches high due to heat generation, the resistance value increases and the amount of current is limited.
The valve is kept closed by maintaining the wax at a high temperature with low power consumption.

In this starting fuel adjustment device 2, the upstream portion 8a and downstream portion 8b of the starting intake passage 8 are perforated with high precision due to the fact that the carburetor body 4 is formed by die-casting of aluminum. Although this is difficult, since the inlet 17 and outlet 18 of the sleeve 12 can be machined with high precision, control accuracy can be improved.

Moreover, since the inlet 17 and the outlet 18 are provided in a straight line, the negative pressure acting on the starting fuel nozzle 9 can be increased, which also improves control accuracy. Furthermore, the inlet 17 and the outlet 18
Furthermore, the degree of freedom in selecting the position and shape of each of the recesses 19 and 20 is improved.

By the way, in the conventional type, since the inlet 17 and the outlet 18 are provided directly in the vaporizer main body 4, the inlet 17 and the outlet 18 are likely to be misaligned, and when this misalignment occurs, the ambient temperature
In the vicinity of 25 to 39°C, variations in air amount/fuel amount occurred as shown by the broken line in Fig. 8, but in this example, the inlet 17 and outlet 18 can be formed with high precision. Coupled with the fact that the opening area is increased at 25 to 39° C., as shown by the solid line in FIG. 8, the air amount/fuel amount can be controlled accurately.

C. Effects of the invention As described above, according to the invention, the inlet and the outlet are controlled to open and close by the sliding throttle valve when the ambient temperature is lower than a predetermined value within the range of 25 to 39°C. a first opening that is fully closed when the temperature is higher than the predetermined value; and a first opening connected to the first opening that is controlled to open and close by a sliding throttle valve when the ambient temperature is higher than the predetermined value; and a second opening that is fully open when the temperature is lower than a predetermined value, and the second opening is formed wider than the first opening in a direction perpendicular to the sliding direction of the sliding throttle valve. At the same time, a step is formed at the boundary between the two openings corresponding to the operating position of the sliding throttle valve when the ambient temperature is at the predetermined value.
The opening area of the inlet and outlet when the temperature is higher than a predetermined value within the range of ~39°C can be made particularly larger than that of the conventional one,
Therefore, by significantly increasing the intake air flow rate when the temperature is higher than the predetermined value, it is possible to effectively prevent the air-fuel mixture from becoming over-enriched, contributing to improved startability of the engine in hot weather. Moreover, such air-fuel mixture concentration control is achieved by forming the inlet and the outlet into a narrow first opening and a wide second opening in the direction orthogonal to the sliding direction of the sliding throttle valve, as described above. Since it can be easily obtained by simply forming a shape in which the two are connected through a step, the increase in cost can be kept to a minimum.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, in which Fig. 1 is an overall longitudinal sectional view, Fig. 2 is an enlarged longitudinal sectional view of main parts, Fig. 3 is a sectional view taken along the - line in Fig. 2, and Fig. 4 is a cross-sectional view taken along the - line in Fig. 2. Fig. 5 is an enlarged side view of the sleeve seen from the opposite side from Fig. 4, Fig. 6 is an enlarged view of the inlet and outlet, and Fig. 7 shows the relationship between ambient temperature and air flow rate. A graph showing the relationship, FIG. 8 is a graph showing the relationship between ambient temperature and air amount/fuel amount. 1... Carburetor, 2... Starting fuel adjustment device, 4...
... Carburetor main body, 5 ... Float chamber, 8 ... Intake path for starting, 10 ... Sliding throttle valve, 11 ... Metering needle valve, 12a ... Slide hole, 17 ... Inflow port, 18 ...
... Outlet, 17a, 18a... Second opening, 1
7b, 18b...first opening, 17e, 18e
……Step.

Claims (1)

[Scope of utility model registration request] A starting fuel nozzle 9 that faces the starting intake passage 8 and communicates with the float chamber 5 is disposed in the middle of the starting intake passage 8 provided in the carburetor main body 4 . Inlet 17 connected to the upstream side
A sliding hole 12a that opens an outlet 18 connected to the downstream side on the inner surface is provided at an angle with the starting intake passage 8, and a sliding throttle valve 10 is slidably fitted into the sliding hole 12a. In order to control the opening areas of the inlet 17 and the outlet 18 from a fully closed state when the ambient temperature is high to a fully open state when the ambient temperature is low, the sliding throttle valve 10 is provided with a In a starting fuel regulating device for a carburetor, which is connected to a temperature-sensitive drive means 24 that operates accordingly,
The inlet 17 and the outlet 18 are controlled to open and close by the sliding throttle valve 10 when the ambient temperature is lower than a predetermined value within the range of 25 to 39°C, and are fully closed when the ambient temperature is higher than the predetermined value. The first openings 17b, 18b, this first opening 17b,
18b, the second openings 17a and 18a are controlled to open and close by the sliding throttle valve 10 when the ambient temperature is higher than the predetermined value, and are fully open when the ambient temperature is lower than the predetermined value; The second
The openings 17a, 18a are the first openings 17b,
18b is formed wider in the direction orthogonal to the sliding direction of the sliding throttle valve 10, and at the boundary between the openings 17a, 17b; 18a, 18b,
A starting fuel adjustment device for a carburetor, characterized in that steps 17e and 18e are formed corresponding to the operating position of the sliding throttle valve 10 when the ambient temperature is at the predetermined value.