JPH0310029B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The disclosed technology belongs to the technical field of air-fuel ratio control of an accelerator for an air valve type carburetor attached to an automobile engine.

<Summary of the gist> Accordingly, the present invention provides an acceleration nozzle between a secondary throttle valve linked to a primary throttle valve of a secondary side barrel attached to the primary side and an air horn side air valve, so that an acceleration nozzle is provided in the float chamber. This invention relates to a secondary accelerator for an air valve type carburetor which is connected to a communicating well and is configured to eject accelerating fuel when a throttle valve is fully open. The lower end opening of each subwell to be connected changes the height from the bottom of the main well housing the subwell to enable multi-stage control, and the main well is connected to the float chamber via a jet of a set size. This invention relates to a secondary acceleration device for an air valve type carburetor.

<Prior art> As is well known, there are various types of carburetors attached to automobile engines, but among them, the compound type so-called air valve type carburetor is popular due to its superior high load characteristics. Widely adopted.

In general, in this type of air valve type carburetor, the transient air-fuel ratio characteristics during acceleration will shift from the slow system to the main system due to fuel inertia, or lean due to a delay in fuel discharge in the transition region from the primary system to the secondary system. Since there is a tendency for richness due to the acceleration system and acceleration system, there is a problem that the richness, leanness, and phase shift of these become rough, deteriorating the torque characteristics of the engine.

To deal with this, in order to improve the joint characteristics between the primary side and the secondary side of the conventional air valve type carburetor, an accelerator is installed near the main nozzle of the secondary barrel, and a version that is not equipped with this type of accelerator is installed near the main nozzle of the secondary barrel. It is designed to have a significant performance improvement compared to the previous version.

<Problems to be Solved by the Invention> However, since such an accelerator is a so-called single-type accelerator in which only one acceleration nozzle communicating with the float chamber is provided, the fuel discharge is a single-stage type, i.e. , there is a drawback that there is a lack of freedom in controlling the jet of a certain amount of fuel or the amount of fuel discharged per hour depending on the jet of one acceleration nozzle. If you decide on this, a lean state will occur during high-speed full-throttle acceleration and a secondary shock will occur, and on the other hand,
If the specifications are matched to full-throttle acceleration from high speed, it will result in sluggishness at low-speed full-throttle acceleration.Therefore, it is necessary to compromise on one predetermined point based on the premise of antinomy and exclusion. Therefore, there is a problem in that it is not possible to make the transient air-fuel ratio as flat as possible over the entire range from low speed to high speed.

On the other hand, for example, in the technology proposed in Utility Model Application Publication No. 56-122757 and in Utility Model Application Publication No. 55-130037, there are technologies in which multiple wells are provided as subwells; All of these are multiple parallel type, so when the car is turning or tilting, a so-called drying up phenomenon occurs at one of the suction ends, reducing the amount of fuel discharged and making it difficult to drive smoothly. There was the inconvenience that stability could not be obtained, resulting in shortness of breath, sluggishness, etc.

<Objective of the Invention> The object of the invention is to solve the problems of the air valve type carburetor based on the above-mentioned prior art, and to solve the problems of the air valve type carburetor based on the above-mentioned prior art. Engine peripheral technology in the automobile industry by providing a nozzle to control the discharge in multiple stages and making the transient air-fuel ratio characteristics of the engine as flat as possible in the entire acceleration range from low speed to high speed. It is an object of the present invention to provide an excellent secondary accelerator for an air valve type carburetor that is useful for various fields of application.

<Means/effects for solving the problem> In order to solve the above problem, the structure of the present invention, which is based on the scope of the above-mentioned claims, is as follows:
Regardless of full-open acceleration from low speed or full-open acceleration from high speed, the secondary throttle valve is linked to the primary throttle valve and is fully opened, and is installed concentrically near the main nozzle in the joint area. A mixing chamber negative pressure equivalent to the intake manifold negative pressure acts on the plurality of acceleration nozzles, and the mixing chamber negative pressure acts on the fuel in the main well through the subwell, and the fuel in the main well flows through the subwell into the mixing chamber. Fuel is discharged at the required discharge amount according to the chamber negative pressure, that is, according to the region from low speed to high speed, and the fuel is discharged from the lower end of one subwell (longer subwell) of the lower opening higher than the bottom of the main well. When the fuel level decreases, the fuel discharge from the other short acceleration nozzle stops and the first stage discharge ends, and then the fuel oil level falls in the next long subwell, and the next stage discharges from the next one acceleration nozzle. (When fuel is being discharged from the short acceleration nozzle, fuel is also being discharged from other nozzles.) During this period, the supplementary fuel from the float chamber is jetted so that it is less than the fuel discharge amount of the multiple stages mentioned above. 10, the air valve gradually opens, and the joints are made smoothly in multiple stages.
The air-fuel ratio is made flat, and finally, when the fuel oil level falls to the lower end opening of the long subwell, it is balanced with the metered replenishment fuel from the jet and discharged steadily, so that multiple subwells are discharged at the same time. It is provided in the shape of a core, and its lower end opening is at a different height than the bottom of the main well, so even when the car is turning or tilting, either side of the intake can be used. Even if the fuel level is below the edge and a drying phenomenon occurs,
Since fuel is sucked from the other lower suction end side, good fuel discharge during acceleration can be obtained, and
Because multiple subwells are arranged concentrically, even if the ring clearance is small, the fuel in the ring gap rises due to the so-called capillary phenomenon, resulting in faster fuel response during acceleration. This technology has taken technical measures that have made it possible to obtain high acceleration performance.

<Example> Next, an example of the present invention will be described below based on the drawings.

Incidentally, the same parts will be explained using the same reference numerals throughout all the figures.

In the embodiment shown in FIG. 1, 1 is the secondary side of the air valve type carburetor, and the barrel 2
An air horn 5 having an air valve 4 is integrally provided on the upper part of the horn 5 with a gasket 3 interposed therebetween.

A secondary throttle valve 7 is connected to a primary throttle valve (not shown) via a link (not shown) on the downstream side of the bore 6 of the barrel 2, and a main nozzle 8 is connected to the upstream side of the bore 6.
is provided.

In addition, a main well 9 is formed in the barrel 2 on the side of the bore, a jet 10 having a measuring function of a set size is provided in the lower part of the main well 9, and a float chamber having an atmospheric port 11 and a float 12 is provided in the upper part. 13.

Note that the amount of jet 10 is measured by nozzles 19 and 20.
The measured amount is smaller than that of either of the jets 17 and 18.

Reference numeral 14 denotes a nozzle block, which is appropriately fixed astride the barrel 2 and the air horn 5, and is also fitted into the upper part of the main well 9. The nozzle block 14 has a set ring-shaped gap in its lower part. Long and short sub-wells 15 and 16 are fixed, and acceleration nozzles 19 and 20 having jets 17 and 18 are fixed in communication with their upper ends, and their lower end openings 21 and 22 are at a set height from the bottom of the main well 9. (the former is low and the latter is high), and the jet 17 has a smaller diameter than the jet 18, and the float chamber 1
3, and main well 9, subwell 15, 1
In a normal state, the oil level of the fuel 23 in the subwell 11 is maintained at the same oil level in the communicating state as shown in the figure and at a set height in the subwell 11.

In the above configuration, when the illustrated state is a non-accelerating state, the primary side (not shown) is in a low-speed full-throttle acceleration state,
Alternatively, when the primary throttle valve (not shown) becomes fully open due to a high-speed, fully-open acceleration state, the secondary throttle valve 7 becomes fully open via a predetermined linkage.

Therefore, the intake manifold negative pressure is at bore 6,
As the air valve 4 gradually opens inside the air horn 5, the negative pressure acts on the jets 17 and 18 of the acceleration nozzles 19 and 20, and the fuel 23 in the main well 9 is present in both the subwells 15 and 16. Also, since the measured amount of the jet 10 is smaller than the measured amount of one discharge nozzle, the fuel 23 is discharged from both jets 17 and 18, but at low speeds (in the early stages of acceleration), the fuel 23 is exclusively discharged from the jet 18 in a relatively small amount. only a small amount of fuel is discharged.

Furthermore, as the acceleration state continues, the oil level of the fuel 23 will drop, and the oil level will drop to the opening 2 of the subwell 16 where the oil level is short.
When descending past 2, the subwell 16, i.e.
Fuel discharge from one acceleration nozzle 20 is stopped,
When the first-stage transition delay correction fuel discharge is completed and the acceleration state continues, the oil level continues to fall due to the suction and discharge of fuel from other acceleration nozzles 19.

During this period, fuel is discharged in the second stage according to the opening degree of the air valve 4, that is, according to the amount of intake air, at a required fuel discharge amount corresponding to the stage at this stage.

During this time, the jet 10 supplies the fuel 23 from the float chamber 13 to the acceleration nozzles 19, 20,
Also, in the case of 19.1, the oil level of the fuel 23 in the main well 9 continues to fall with a relative negative value.
When the fuel reaches the opening 21 of the long subwell 15 and the second stage discharge is completed, fuel is steadily discharged from the acceleration nozzle 19 in balance with the amount supplied from the jet 10.

Therefore, since the amount of fuel corresponding to the amount of air can be supplied in the entire acceleration range from low speed to high speed, the air-fuel ratio becomes flat and the acceleration is stable in the entire acceleration range.

Further, as described above, when the acceleration fuel is discharged from the acceleration nozzles 19 and 20 due to intake manifold negative pressure, the short subwell 16 of the acceleration nozzle 20
finishes discharging fuel earlier than the other long subwell 15, the diameter difference between the jets 17 and 18 of both acceleration nozzles 19 and 20 (the latter is made larger than the former)
It is possible to improve the joint characteristics by designing such as.

It goes without saying that the embodiment of the present invention is not limited to the above-mentioned embodiment, and various embodiments can be adopted, such as, for example, it is possible to have three or more stages of subwells.

<Effects of the Invention> As described above, according to the present invention, in an acceleration device in which an acceleration nozzle is provided near the main nozzle of a secondary valve of an air valve type carburetor and is connected to a float chamber via a main well, By providing a plurality of sub-wells with different lower end opening heights in the main well and each having an acceleration nozzle, the discharge amount of acceleration fuel can be adjusted to the intake air amount over the entire acceleration range from low speed to high speed. It is possible to make the air-fuel ratio characteristics as flat as possible during the transition from the primary system to the secondary system by changing the air-fuel ratio according to the system, which has the excellent effect of eliminating secondary shock, breathing, and sluggishness. is played.

Therefore, there is an effect that the rise characteristics of the engine torque during transient times can be improved.

Also, since there are no moving parts in the well and nozzle,
It also has the advantage of no vibration, fewer breakdowns, and almost no need for maintenance or inspection.

Therefore, in this invention, a plurality of sub-wells are provided concentrically within the main well, and the heights of the lower suction ends from the bottom surface of the main well within the main well are made to differ. , 1st
Even if the ring-shaped gap between the subwells is small, capillary action works, raising the fuel between each subwell, making the fuel response faster during acceleration, and having the excellent effect of promoting good acceleration. It is played.

Further, by providing the sub-wells concentrically, there is an advantage that even if the ring-shaped clearance is made small, the area of the ring-shaped gap can ensure a necessary diameter in terms of design.

By providing a plurality of concentric subwells, even if the fuel dries up at the bottom opening of at least one subwell even when the vehicle is turning or tilting, it is possible for the fuel to flow from the bottom opening of other subwells. This has the effect of providing good fuel discharge and good acceleration.

[Brief explanation of the drawing]

The drawing is a schematic cross-sectional view of one embodiment of the present invention. 1... Accelerator, 2... Secondary barrel, 4
...Air valve, 7...Throttle valve, 9...
...Main well, 10...Jet, 13...Float chamber, 9,15,16...Well, 15,1
6...Subwell, 19,20...Acceleration nozzle,
21, 22...opening.

Claims (1)

[Claims] 1. In a secondary accelerator for an air valve type carburetor, in which an accelerating nozzle faces between the throttle valve and the air valve of the secondary barrel, and the accelerating nozzle is connected to an accelerating well that communicates with a float chamber, a main The wells are connected to each other, a plurality of sub-wells having lower end openings having different heights from a bottom surface of the main well are provided concentrically in the main well, and an acceleration nozzle is provided at the tip of each of the plurality of sub-wells. A secondary accelerator for an air valve type carburetor.