JPH0738677Y2 - Combined carburetor with limited secondary throttle valve opening - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention, when the output regulation of a vehicle engine is required,
The present invention relates to a configuration of a composite carburetor that can easily cope with output limitation without changing the engine displacement and the diameter of the intake passage of the carburetor.

[Prior Art] FIG. 3 shows a structure of a vehicle engine speed control device disclosed in Japanese Patent Publication No. 51-17644, in which reference numeral 1 is a housing of a composite carburetor, 2 is a primary side intake passage, A primary side throttle valve 3 that is opened and closed by the driver's accelerator operation is arranged,
Reference numeral 4 denotes a secondary side intake passage, a secondary side throttle valve 5 is arranged, and a primary side venturi portion 6 is provided in the primary side intake passage 2.
A secondary venturi portion 7 is formed in the secondary intake passage 4. Reference numeral 8 is a negative pressure device for opening and closing the secondary throttle valve 5,
A negative pressure chamber 12 is formed by a diaphragm 11 that is connected to a turning lever 9 of the secondary throttle valve 5 by a connecting member 10, and a coil spring 13 is arranged on the negative pressure chamber 12 side. The rotation lever 9, the coupling member 10 and the diaphragm 11 are urged in the direction in which the secondary throttle valve 5 is closed. In the negative pressure chamber 12, the primary side venturi section 6 and the secondary side venturi section 7 are passed through a negative pressure extraction passage 14 and a communication passage 15 which open to the primary side venturi section 6 and the secondary side venturi section 7. Intake negative pressure generated in 7 or atmosphere open passage
16, atmospheric pressure is introduced through the communication passage 15. Reference numeral 17 denotes a solenoid valve, which does not operate when the engine speed is low, shuts off the atmosphere release passage 16, and the intake negative pressure of the primary side venturi section 6 and the secondary side venturi section 7 is the above-mentioned. Although guided to the negative pressure chamber 12, when the rotation speed of the engine rises above a set value, the voltage of the generator 18 rotating with the engine rises, the Zener diode 19 becomes conductive, and the transistor 20 is turned on.
Current flows from the power source 21 to the solenoid valve 17 to open the valve, and the atmosphere opens to the negative pressure chamber.
Inflow to 12. The secondary throttle valve 5 opens according to the strength of the negative pressure in the negative pressure chamber 12, and closes when the atmospheric pressure flows into the negative pressure chamber 12 and the negative pressure becomes weaker, thereby rotating the engine. Is prevented from exceeding the set value.

FIGS. 4 and 5 show a vehicle speed limiting device disclosed in Japanese Examined Patent Publication No. 53-22205, and reference numerals 1 to 14 and 16 show the same contents as in the case of FIG. 3, but FIGS. In the case shown in the figure, a second diaphragm 22 is further used in the negative pressure device to form a second negative pressure chamber 23, and the second negative pressure chamber 23 is provided with a switching solenoid valve 24 for the engine. The negative pressure or atmospheric pressure generated in the intake pipe is introduced. Reference numeral 25 is a negative pressure passage communicating with the intake pipe of the engine, and 26 is a second coil spring for urging the second diaphragm 22 in the direction in which the secondary throttle valve 5 is closed. The switching solenoid valve 24 guides the negative pressure in the intake pipe of the engine to the second negative pressure chamber 23 until the rotational speed of the engine reaches the set value, and the second diaphragm 22 operates the second coil spring 26. When compressed, the state shown in FIG. 4 is reached, and the intake negative pressures of the primary and secondary venturi parts 6 and 7 are introduced into the negative pressure chamber 12, and the secondary throttle valve is determined according to the strength of the negative pressure. 5 is controlled to open and close, but when the rotational speed of the engine exceeds the set value, the switching solenoid valve 24 introduces the atmosphere into the second negative pressure chamber 23, and the second diaphragm 22 causes the second coil spring 26 to move.
As shown in FIG. 5, the negative pressure chamber 12
Even if the intake negative pressure of the primary side Venturi part 6 and the secondary side Venturi part 7 acts, the secondary side throttle valve 5 is closed,
Prevents the engine from exceeding the set speed.

[Problems to be Solved by the Invention] In the structure of Japanese Patent Publication No. 17644/1976, a solenoid valve and an electric control means for operating the solenoid valve are required to limit the engine rotation speed to a set value or less, resulting in high cost. In the configuration disclosed in Japanese Examined Patent Publication No. Sho 53-22205, the negative pressure device is the second
There is a problem that the diaphragm is required and the cost is further increased.

Therefore, it is an object of the present invention to obtain a compound type carburetor capable of limiting the output of the engine by limiting the opening of the secondary throttle valve at low cost.

[Means for Solving the Problems] When attaching the negative pressure device 8 to the housing 1 of the composite carburetor, a screw member for attaching the negative pressure device 8 is used to make the secondary throttle valve 5 A rotation limiting member that limits the rotation angle of the rotation lever 9 is fastened and fixed to the housing 1 together with the negative pressure device 8.

[Operation] If the rotation control member is selected according to the required limited output, the opening degree of the secondary throttle valve 5 will be irrespective of the negative pressure generated in the primary venturi portion 6 and the secondary venturi portion 7. Can be limited to the allowable maximum opening degree or less to limit the output of the engine. Moreover, the rotation restricting member can be easily manufactured at low cost by using a plate material. Even if the rotation limiting member is attached, there is no change in the performance and drivability until the secondary throttle valve 5 opens at the set angle.

[Configuration of Device] A primary side intake passage and a secondary side intake passage are provided, and a primary side throttle valve that is opened and closed by an access operation of a driver is disposed in the primary side intake passage. The secondary intake passage is opened and closed by a negative pressure device operated by negative pressure guided by a negative pressure extraction passage opening to the venturi portion of the primary intake passage and the venturi portion of the secondary intake passage. In a compound type carburetor in which a side throttle valve is arranged, and a rotary lever of the secondary side throttle valve and a diaphragm of the negative pressure device are coupled by a coupling member, a rotary angle of the rotary lever is set to a set angle. A configuration in which a rotation limiting member to be limited to the following is fixed to the housing of the compound carburetor by a screw member common to the negative pressure device to limit the opening degree of the secondary side throttle valve.

[Embodiment] FIG. 1 is a view showing the structure of a compound type carburetor with a limited secondary throttle valve according to the present invention. Reference numerals 1 to 14 have the same contents as those in FIGS. 3 and 4. Besides, 8-1 is a bracket of the negative pressure device for attaching the negative pressure device 8 to the housing 1, 27 and 28 are screw members for attaching the negative pressure device 8 to the housing 1, and 29 is 2
It is a rotation limiting member that limits the rotation lever 9 of the secondary throttle valve 5 from rotating more than a set rotation angle, and is overlapped with the bracket 8-1 of the negative pressure device 8 by a common screw member 27. The rotation restricting member 29 is fixed to the housing 1.

2 is a sectional view taken along the line II-II of FIG. 1, and the reference numerals in the drawing show the same contents as in FIG. 1, and 29-1 is a bending of the rotation restricting member 29. At a portion, the rotation restricting member 29 fixed by one screw member 27 is prevented from being displaced around the screw member 27. The contact portion of the rotation limiting member 29 with the rotation lever 9 is formed in an arc having a radius R, and even if the rotation limiting member 29 slightly shifts around the screw member 27, the rotation lever is formed. The rotation angle range of 9 does not change. In FIG. 1, the broken line shows the positions of the secondary throttle valve 5 and the rotation lever 9 when the secondary throttle valve 5 is fully closed, until the rotation lever 9 contacts the rotation limiting member 29. It can rotate by an angle θ. In the structure shown in FIG. 1, since the coil spring of the close winding is used as the connecting member 10 for connecting the rotating lever 9 and the diaphragm 11, the diaphragm 11 after the rotating lever 9 and the rotating restricting member 29 are in contact with each other.
Can be dealt with by the expansion of the coil spring, and an unreasonable force does not act between the diaphragm 11 and the coupling member 10.

When the primary throttle valve 3 increases the opening degree by the driver's accelerator operation and the negative pressure of the venturi portion 6 of the primary intake passage 2 acting on the negative pressure chamber 12 reaches a certain strength, the diaphragm 11 is coiled. Compress the spring 13 and open the secondary throttle valve 5,
Negative pressure is also generated in the venturi portion 7 of the secondary side intake passage 4,
After that, as the opening degree of the secondary side throttle valve 5 increases and the negative pressure in the negative pressure chamber 12 increases as the engine speed increases, the opening degree of the secondary side throttle valve 5 increases. After the rotation lever 9 of the valve 5 contacts the rotation limiting member 29, the throttle valve 5 stops opening and the output of the engine is limited.

[Effects] When mounting the negative pressure device on the housing of the compound type carburetor, the rotation angle of the secondary side throttle valve can be adjusted simply by mounting the low-cost rotation limiting member for forming the plate material with the common screw member. Can be suppressed to meet the demand for engine output limitation.

[Brief description of drawings]

FIG. 1 is a view showing the structure of a compound type carburetor in which the opening of the secondary side throttle valve of the present invention is limited, and FIG. 2 is a sectional view taken along the line II-II in FIG. 1, FIG. 3, and FIG. FIG. 5 and FIG. 5 are diagrams showing a conventional configuration. DESCRIPTION OF SYMBOLS 1 ... Casing of complex type carburetor, 2 ... Primary side intake passage 3 ... Primary side throttle valve, 4 ... Secondary side intake passage 5 ... Secondary side throttle valve, 6 ... Primary side intake passage Venturi part, 7 ... Venturi part of secondary side intake passage, 8 ... Negative pressure device, 8-1 ... Bracket of negative pressure device, 9 ... Secondary side throttle valve turning lever, 10 ... Coupling member, 11 ... Diaphragm, 12 ...
Negative pressure chamber, 13 ... Coil spring, 14 ... Negative pressure extraction passage, 2
7, 28 ... Screw member, 29 ... Rotation restriction member, 29-1 ... Bent portion.

Claims (1)

[Scope of utility model registration request] 1. A primary side intake passage (2) and a secondary side intake passage (4), wherein the primary side intake passage (2) is opened and closed by an accelerator operation by a driver. Throttle valve (3)
And is open to the venturi portion (6) of the primary intake passage (2) and the venturi portion (7) of the secondary intake passage (4) in the secondary intake passage (4). A secondary throttle valve (5) that is opened and closed by a negative pressure device (8) that is operated by the negative pressure introduced to the negative pressure extraction passage (14) is arranged, and a rotating lever of the secondary throttle valve (5). (9) and the diaphragm (11) of the negative pressure device (8) are coupled members (10)
In the compound type carburetor coupled by means of a screw member common to the negative pressure chamber device (8), a rotation limiting member (29) for limiting the rotation angle of the rotation lever (9) to a set angle or less. (27) A compound vaporizer characterized by being fixed to the casing (1) of the compound vaporizer by means of (27) to limit the opening of the secondary throttle valve (5).