JPS6127575B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a compound carburetor for use in a multi-cylinder engine.

As a compound carburetor used in a multi-cylinder engine,
After the primary air-fuel mixture passes through one primary throttle valve, it is distributed to each cylinder, and the secondary air-fuel mixture is supplied to each cylinder via the secondary throttle valve provided for each cylinder. , the secondary side throttle valve is opened and closed by an actuator that synthetically introduces both the negative pressures of the primary side bench lily and the secondary side bench lily, but in this type of conventional compound carburetor, generally only one actuator is used. Because only one cylinder was installed at one end of the cylinder row, the frictional resistance that is applied to the throttle shaft is not only the frictional resistance caused by normal intake negative pressure pushing one side toward the engine side, but also the frictional resistance caused by the cantilever-like tilting. As the number of cylinders increases, the frictional resistance tends to increase as a whole and increases as the distance from the actuator increases. Due to the frictional resistance caused by this fall, the opening and closing of the secondary throttle valve may not be smooth, and the opening degree of the secondary throttle valve may differ between the actuator installation side and the opposite side. There was a problem in that the air-fuel ratio of each cylinder varied during the process of connection to the next side. Further, when there is only one actuator, there are disadvantages in that the actuator inevitably becomes large in size and there are large variations in operation. Furthermore, if there is only one actuator, the number of times the throttle shaft moves in the thrust direction when the throttle valve rotates will increase, and the friction between the secondary throttle valve and the inner wall of the secondary bore will increase, resulting in poor durability. The drawback was that it weakened the sex.

In order to eliminate the above-mentioned drawbacks, the present invention aims to provide a composite carburetor in which a plurality of actuators are arranged at least at both ends of a cylinder row. To explain, 1 is a primary side bore having a bench lily 1a, 2 is a primary side main nozzle, 3 is a primary side main well, 4 is a primary side main jet, 5 is a primary side throw system, and 6 is a primary side throttle valve. , the downstream side of the primary throttle valve 6 of the primary bore 1 is branched and connected to each cylinder. 7 is a secondary side bore having a bench lily 7a, 8 is a secondary side main nozzle, 9 is a secondary side main well, and 10 is a secondary side main jet, which is located downstream of the secondary side bench lily 7a of the secondary side bore 7. The sides are branched and connected to each cylinder. 11
12 is a secondary throw system provided on the inner wall of each branch part 7b of the secondary bore 7, and 12 is a secondary throw system that penetrates each branch part 7b in a direction perpendicular to the center line of the branch part 7b. Side throttle shafts 13 are respectively fixed to the secondary throttle shafts 12 in each branch 7b, and 14 are a pair of secondary throttle valves fixed to both ends of the secondary throttle shafts 12. The side throttle levers 15 are arranged at both ends of the cylinder row, and the negative pressure chamber 15a is connected to the negative pressure passage 16.
It communicates with both the primary bench lily 1a and the secondary bench lily 7a via the diaphragm 15.
A pair of actuators b are connected to the secondary throttle lever 14 via a rod 17, and the actuator 15 is connected to the primary bench lily 1a.
It is operated by the combined negative pressure of the secondary side bench lily 7a.

Since the compound carburetor according to the present invention is constructed as described above, when the accelerator pedal (not shown) is depressed during engine operation, the opening degree of the primary throttle valve 6 is increased, and as a result, the negative pressure near the bench lily 1a is increased. It gradually increases and a richer air-fuel mixture is distributed and supplied to each cylinder. Next, when the rotational speed of the engine increases, the air flow rate increases, and the negative pressure near the bench lily 1a further increases, the actuator 15 operates to rotate the throttle shaft 12 to the right as shown in FIG. The opening degree of the throttle valve 13 is increased. Therefore, the negative pressure near the secondary side bench lily 7a gradually increases, and appropriate air-fuel mixture is additionally supplied to each cylinder. When the accelerator pedal is released after achieving the required increase in engine output, the primary throttle valve 6 is returned to the illustrated position. As a result, the negative pressure near the bench lily 1a decreases, so the actuator operates in reverse and the throttle shaft 1
2 is rotated to the left, and each secondary throttle valve 13 is returned to the illustrated position.

The compound carburetor according to the present invention operates as described above, but since the pair of actuators 15 are disposed at both ends of the cylinder row, the throttle shaft 12
Frictional resistance due to cantilever-like inclination is almost eliminated, and as a result, opening and closing of the secondary throttle valve 13 becomes extremely smooth. In addition, since the frictional resistance due to falling is eliminated, there is no deviation in the opening degree of the secondary throttle valve 13 at the beginning of opening, so the amount of leakage from each secondary throttle valve 13 to each cylinder is averaged, and as a result, the amount of leakage from each secondary throttle valve 13 to each cylinder is averaged. In the process of connection from the cylinder to the secondary side, variations in air-fuel ratio for each cylinder are minimized.
Furthermore, since there are two actuators 15, the actuator 15 is miniaturized and its operation is stable. Furthermore, since the pair of actuators 15 are located at both ends of the cylinder row, the number of times the throttle shaft moves in the thrust direction when the throttle valve rotates is reduced, and as a result, the secondary throttle valve 13 and the Since the warping with the inner wall of the branch portion 7b of the bore 7 is also reduced, durability is increased.

In the above embodiment, the pair of actuators 1
Although actuators 15 are disposed at both ends of the cylinder row, if the number of cylinders increases, an additional actuator 15 may be additionally disposed in the middle of the cylinder row. In addition, in the above embodiment, there is one throttle shaft 12, but it is technically preferable to have one throttle shaft 12 for every two cylinders, so for example, in the case of three cylinders and four cylinders, If you have two or six cylinders, it is better to use three. In this case, since each throttle shaft 12 is naturally connected by a synchronizing/engaging link, etc., there is a risk that the rotation of the throttle shaft 12 will not be smooth due to eccentricity of the engaging portion. Furthermore, the problem can be solved by providing a plurality of actuators 15 and arranging them at least at both ends of the cylinder row.

As described above, in the compound carburetor according to the present invention, the opening and closing of the secondary side throttle valve is extremely smooth, and variations in the air-fuel ratio of each cylinder are minimized in the process of connection from the primary side to the secondary side. This has many important practical advantages, such as miniaturization of the actuator, stabilization of operation, and increased durability.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of an embodiment of a composite vaporizer according to the present invention, and FIG. 2 is a cross-sectional view taken along the line of FIG. 1. 1... Primary side bore, 2... Primary side main nozzle, 3
...Primary side name main well, 4...Primary side main jet, 6...Primary side throttle valve, 7...Secondary side bore, 8...
Secondary side main nozzle, 9...Secondary side main well,
10... Secondary side main jet, 12... Secondary side throttle shaft, 13... Secondary side throttle valve, 14... Secondary side throttle lever, 15... Actuator,
16... Negative pressure passage, 17... Rod.

Claims (1)

[Scope of Claims] 1. The secondary air-fuel mixture is supplied to each cylinder via the secondary throttle valve provided for each cylinder, and the opening and closing of the secondary throttle valve is controlled by the primary vent lily and the secondary throttle valve. A compound carburetor operated by an actuator that synthetically introduces both negative pressures of a next side bench lily, characterized in that a plurality of said actuators are arranged at least at both ends of a cylinder row. 2. The composite carburetor according to claim 1, wherein the actuator is also disposed in the middle of the cylinder row.