JPS6141972Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The disclosed technology belongs to a structural technology that has a transient compensation function for fuel supply by a feeding well of an air valve type carburetor of an automobile.

Therefore, this invention aims to increase the amount of fuel delivered from the acceleration well in accordance with the fuel required by the engine when the throttle valve of the secondary side barrel attached to the primary side barrel of the air valve type carburetor is fully opened. This is a device related to an acceleration well structure that compensates for the amount of discharged fuel.In particular, it has a lower end slightly above the fully closed position of the air valve and an upper end slightly above the fully closed position of the air valve, so that the amount of cover on the air valve decreases when accelerating from low speeds. A bleed port is provided whose size increases during deceleration from full-open acceleration, and the amount of fuel or fuel discharged from the acceleration well is controlled by bleed air passing through the air bleed passage according to the air valve opening degree. This invention relates to a secondary acceleration well structure for an air valve type carburetor that can compensate for the optimum air-fuel ratio under all operating conditions.

<Prior Art> As is well known, there are various types of carburetors that are installed in engines installed in automobiles, and among them, there is a so-called air valve type carburetor that has an air valve in a secondary barrel.

Although this type of air valve type carburetor has various merits, until now there has been a problem in that the transient characteristics during acceleration with the primary side throttle valve fully open are not good.

That is, the air valve type carburetor compensates for the transient air-fuel ratio by using a combination of an acceleration pump and an acceleration well as its transient compensation mechanism.

Incidentally, as shown in Fig. 1, when the throttle valve of the primary side barrel of the air valve type carburetor 1 is in the fully open acceleration state, the secondary side barrel 2
When the throttle valve 3 is suddenly opened, the negative pressure of the intake manifold spreads into the mixing chamber 4, and an increased amount of fuel is ejected from the main nozzle 11. However, in order to compensate for the delay, the intake manifold negative pressure spreads into the mixing chamber 4. A negative pressure is temporarily formed in the float chamber, and the fuel from the fuel reservoir is injected in a transient compensatory manner.Then, the air valve 6 opens in the adaptive state, and the needle 9 of the float chamber 8 is injected into the jet 10 via the link 7. When opened, fuel is injected from the main nozzle 11, and at the same time, fuel is sucked and ejected from the acceleration well 5.

<Problems to be solved by the invention> However, in this type of acceleration well mechanism, although the discharge amount of the acceleration pump is constant and the fuel discharge amount from the acceleration well is also constant, the Due to the difference, the required fuel discharge amount during acceleration with the throttle valve fully open changes.

In other words, the required fuel discharge amount is small when accelerating from low speeds, but it is large when accelerating from high speeds.Nevertheless, the amount of intake air changes depending on the opening degree of the air valve, so the air-fuel ratio The drawback was that the required output air-fuel ratio could not be maintained.

To deal with this, if the design is designed to match acceleration from high speeds, it will become overrich at low speeds, causing breathiness and surging in terms of drivability, and conversely, it will be difficult to accelerate from low speeds. When matched, there was a problem that it became over lean and caused sluggishness.

Furthermore, even if it is possible to control using an electronic detection mechanism depending on the design, the structure becomes complicated and
The disadvantage was that the maintenance was troublesome but the result was not worth it.

The purpose of this invention is to solve the technical problem of transient compensation during full-open acceleration of the air valve type carburetor based on the above-mentioned conventional technology, and to solve the problem of transient compensation during full-open acceleration of the air valve type carburetor based on the above-mentioned conventional technology. This is an excellent air valve type carburetor that utilizes the temporary rise in negative pressure caused by the air valve to automatically control the amount of fuel sucked by the air valve opening, resulting in good transient response characteristics and is beneficial to engine technology in the automobile industry. It is intended to provide a secondary acceleration well structure.

<Means/effects for solving the problems> In accordance with the above-mentioned purpose, the structure of this invention, which is summarized in the scope of the above-mentioned utility model registration claims, is to solve the above-mentioned problems in an air valve type carburetor.
When the primary throttle valve is fully open and the secondary throttle valve is fully open and accelerated, and the air valve is opened to a greater degree, the amount of air valve cover over the bleed port provided on the air valve side is reduced, and from there. A small amount of bleed air is introduced by small dynamic pressure to increase the fuel discharge amount of the acceleration well, preventing the air-fuel ratio from becoming lean and achieving an appropriate air-fuel ratio.On the other hand, when the air valve opening becomes smaller after full acceleration, bleed air The amount of air valve covering the port is large and the bleed port is opened, increasing the amount of air bleed.
The fuel discharge amount is reduced to prevent over-richness,
By setting the air-fuel ratio to be appropriate for the operating condition, it is possible to maintain good drivability by discharging fuel that matches the engine's required fuel discharge amount even when the throttle valve is fully opened and acceleration is accelerated under any engine operating condition. This was achieved by taking technical measures to achieve this goal.

<Example> Next, an example of this invention will be described below based on the drawings from FIG. 2 onwards. Note that the same parts as those in FIG. 1 will be described with the same reference numerals.

In the embodiment shown in FIG. 2, reference numeral 1 indicates the secondary side of the air valve type carburetor, and a throttle valve 3 is provided on the downstream side of the secondary side barrel 2, and an air valve 6 is provided on the upstream side so as to be pivotable to the shaft. supported.

Thus, an air bleed port 12 is opened at a position upstream of the set height of the air valve 6, an air bleed passage 13 is connected to the main nozzle 11, and further,
Jet 1 of float chamber 8 via fuel passage 14
Connected to 0.

A link 7 connected to the air valve 6 is connected to a needle 9 facing the jet 10 of the float chamber 8.

Thus, the acceleration passage 1 facing the float chamber 8
5 is connected to an acceleration well 5 having a throttle 16 and opening into the mixing chamber 4 upstream of the throttle valve 3.

Further, 17 is an air bleed passage, and a throttle 18
It is connected to the acceleration well 15 via the air bleed port 12 and to the bleed port 19 that opens between the air bleed port 12 and the main nozzle 11 .

The bleed port 19 forms part of the gist of this invention, and its opening position is set along the axial direction of the barrel at a position slightly higher than the position inside the barrel when the air valve 6 is fully closed. The opening is in the shape of a long hole.

In the above configuration, the primary throttle valve (not shown) is brought into a fully open accelerated state, and the secondary throttle valve 3 linked thereto
When the engine is fully opened and shifted to the acceleration position, the negative pressure in the intake manifold spreads to the mixing chamber 4, and the air valve 6 is opened by the negative pressure.

Thus, the delay in increasing the amount of fuel discharged from the main nozzle 11 is compensated for by utilizing the negative pressure temporarily generated in the acceleration well 5 to urge the fuel to be ejected.

By the way, as shown in Fig. 4, the air valve opening deg on the vertical axis is proportional to the engine rotation speed RPM on the horizontal axis from acceleration A to full opening B, so the opening degree of the air valve 6 is proportional to the engine rotation. It is possible to consider it instead of a number.

Therefore, fuel is sucked in from the acceleration well 5 in a compensatory manner as described above in proportion to the opening degree of the throttle valve 3. In this case, the air valve 6 is
As shown in Fig. 3, since the opening amount, that is, the covering amount S for the bleed port 19 is different, the dynamic pressure of the air in the bleed port 19 changes, and the acceleration passage 1
The amount of bleed air in the air bleed passage 17 connected to the air bleed passage 17 will change.

That is, in the full-open acceleration process from the low speed side, the degree of fog S gradually decreases, the pressure decreases, the amount of bleed air decreases, and therefore the amount of suction fuel discharged from the acceleration well 5 to compensate is As a result, the air-fuel ratio becomes rich in proportion to the increase in the air valve opening, the engine speed increases, and acceleration is performed smoothly.

Next, in the process of transitioning from full-open acceleration to low speed, the opening degree of the air valve 6 is reduced, and the degree of cover S on the bleed port 19 increases, so the amount of bleed air increases, and the acceleration passage 15
The amount of fuel discharged from the acceleration well 5 decreases, the air-fuel ratio is automatically controlled to the lean side, and the engine speed decreases.

In this way, the amount of fuel discharged from the acceleration well 5 is automatically controlled according to the opening degree of the air valve 6.

Therefore, even when the driving state shifts to full throttle acceleration, it can completely automatically and immediately respond to the required fuel discharge amount from the engine side, resulting in stable drivability without sluggishness, sluggishness, surging, etc. is obtained.

It goes without saying that the embodiment of this invention is not limited to the above-mentioned embodiments, and the design can be changed freely.For example, the bleed port is not limited to a long hole shape, but may be circular, oval, diamond, or round. Various designs such as shapes are possible.

<Effects of the invention> As described above, according to this invention, in the structure of the acceleration well provided in the secondary barrel of the air valve type carburetor, the air bleed passage is connected to the acceleration passage of the acceleration well that opens upstream of the throttle valve. By connecting the air valve to the bleed port that opens slightly above the set height of the air valve fully closed position, the air valve, which basically opens according to the throttle valve opening, changes the amount of cover on the bleed port. The amount of bleed air is sent into the acceleration passage in inverse proportion to the air valve opening, and as a result, the amount of fuel discharged from the acceleration well is proportional to the air valve opening, which compensates for the delay in fuel output from the main nozzle during acceleration. Even with the amount of intake air that changes depending on the air valve opening, the acceleration air-fuel ratio will not become over-rich or over-lean, allowing full-throttle acceleration from any operating condition or full-throttling acceleration. It has the excellent effect of providing stable drivability without any breathing, sluggishness, surging, etc. even when decelerating from .

In addition, the structure is simple and requires only an air bleed passage connected to the acceleration passage of the conventional acceleration well and a bleed port, so it has the advantage of being simple and low cost, and there is almost no need for maintenance and inspection. Therefore, there is an advantage that maintenance is not a hassle.

[Brief explanation of the drawing]

FIG. 1 is a schematic longitudinal sectional view of the secondary side acceleration well of an air valve type carburetor based on the prior art;
Figure 2 and the following are explanatory diagrams of one embodiment of this invention. Figure 2 is a schematic vertical cross-sectional view of the whole, Figure 3 is a schematic diagram of the operation, and Figure 4 is a graph of engine speed and air valve opening characteristics. It is a diagram. 2... Secondary side barrel, 3... Throttle valve, 6... Air valve, 5... Acceleration well,
8...Float chamber, 15...Acceleration passage, 17...
Air bleed passage, S...coverage, 19...bleed port.

Claims (1)

[Scope of utility model registration request] In the structure of the acceleration well that faces between the throttle valve and the air valve of the secondary side barrel attached to the primary side barrel, the air bleed passage branched from the acceleration passage communicating with the float chamber and connected to the acceleration well is as described above. The lower end is slightly above the fully closed position of the air valve, and the upper end is located at the upstream position where the air valve cover increases and changes as the air valve opening decreases from the air valve's fully open position. The secondary acceleration well structure of an air valve type carburetor is characterized in that it is connected to a bleed port that forms and opens into the barrel.