JPH0444837Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a general-purpose engine with a carburetor, which has a butterfly-type choke valve and a throttle for adjusting ventilation resistance between the carburetor and the air cleaner.

[Conventional technology]

An example of a conventional device will be explained based on FIGS. 6 to 8.

1 is a carburetor body, 2 is a butterfly type choke valve, 3 is an air bleed pressure sampling port, 4 is a throttle valve, and 5 is an air cleaner, but even if the model is the same, the type of air cleaner 5 depends on the type of work equipment and operating environment conditions. There are many different types, and their ventilation resistances vary greatly.

Therefore, the carburetor adjustment is performed for each air cleaner, but in order to reduce the difference in resistance between the air cleaners 5, a throttle 6' is inserted between the carburetor 1 and the air cleaner 5 to facilitate carburetor adjustment. There is.

[The problem that the idea aims to solve]

In the above engine, the suction passage between the throttle and the air bleed pressure sampling port of the carburetor is partitioned into two suction passages by a butterfly type choke valve.

However, the throttle 6 may become eccentric with respect to the center of the suction passage due to variations during processing and assembly.
FIG. 8 shows an example where the diaphragm 6 is eccentric.

2 separated by a butterfly type choke valve 2
Since the passage areas of the two suction passages 7a, 7b at the inlet of the carburetor differ depending on the eccentricity of the throttle 6, the amount of air flowing into the two suction passages 7a, 7b also differs. Since the butterfly type choke valve 2 has a structure that prevents the flow of incoming air in the circumferential direction of the tube wall, the pressure within both suction passages 7a and 7b reaches the air bleed pressure sampling port 3 without being balanced.

In other words, the pressure applied to the air bleed pressure sampling port 3 changes depending on the eccentricity of the throttle 6, which causes a problem in that the fuel flow rate varies and engine performance changes.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention provides a general-purpose engine with a carburetor in which a throttle for adjusting ventilation resistance is provided between a carburetor having a butterfly type choke valve and an air cleaner. The present invention is characterized in that it is constructed into two passages that are partitioned to be identical so that the amount of intake air to both intake passages is constant.

[Effect]

By forming the restriction as described above, the amount of intake air to the suction passage at the inlet of the carburetor remains constant regardless of whether or not the restriction is eccentric, so the pressure applied to the air bleed pressure port is also constant. .

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 5.

Figures 1 to 3 show the first embodiment, and 1 to 7 in the figures are the same as the conventional one described above. Partition part 6 in the center of the aperture hole 6
a so that a throttle hole, that is, a passage for intake air, is formed symmetrically with respect to the butterfly type choke valve 2.

Therefore, the inlet areas of the suction passages 7a and 7b of the vaporizer 1 are equal, and the amount of air flowing into both passages is also equal, so that the pressure applied to the air bleed pressure sampling port 3 is constant. Note that the L dimension in the figure is a dimension that can sufficiently cover the amount of eccentricity caused by variations during processing and assembly.

FIG. 3 shows a case where the throttle 6 is eccentric with respect to the center of the suction passage, but since the area of the divided throttle hole (passage) does not change, the area of the inlet part of the carburetor 1 of the suction passages 7a and 7b does not change. This is the same as when the throttle 6 is not eccentric, and the pressure in the suction passages 7a and 7b does not change, and the pressure applied to the air bleed pressure sampling port 3 also remains constant.

Next, a second embodiment shown in FIGS. 4 and 5 will be described.

In the first embodiment, the throttle 6 is constructed separately and interposed between the carburetor body 1 and the air cleaner 5, but in this embodiment, the throttle 6 is installed in the main body that constitutes the air cleaner 5. 5a, and a partition part 6a similar to the above embodiment is provided at the center of the throttle hole.
It has the same function and effect as the embodiment, and the aperture 6
Since it is formed integrally with the main body 5a of the air cleaner 5, the number of parts can be reduced.

[Effect of idea]

As explained above in detail, according to the present invention, even if an airflow resistance adjusting throttle is provided between the carburetor and the air cleaner, the two suction passages separated by the butterfly-type choke valve at the inlet of the carburetor will always maintain a constant level. Since the amount of air can be sucked in, the pressure applied to the air bleed pressure port is always constant, and the fuel flow rate is also constant, so stable engine performance can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a first embodiment of the present invention;
Fig. 2 is a sectional view taken along line A-A in Fig. 1, Fig. 3 is a view corresponding to the sectional view taken along line A-A when the aperture is installed eccentrically, and Fig. 4 is a sectional view showing the second embodiment. FIG. 5 is a sectional view taken along line B-B in FIG. 4. FIG. 6 is a cross-sectional view of the conventional one, FIG. 7 is a cross-sectional view taken along the line D-D in FIG. 6, and FIG. 8 is a view corresponding to the cross-sectional view taken along the line D-D when the diaphragm is mounted eccentrically. 1 is the carburetor body, 2 is the butterfly type choke valve, 3 is the air bleed pressure sampling port, 4 is the throttle valve, 5 is the air cleaner, 6 is the throttle, 6a is the partition, 7a and 7b are partitioned by the butterfly type choke valve 2. intake passage.

Claims (1)

[Scope of utility model registration request] In a general-purpose engine with a carburetor, in which a throttle for adjusting ventilation resistance is provided between a carburetor having a butterfly-type choke valve and an air cleaner, the throttle is a partition having a constant width provided immediately upstream of the choke valve. 1. A general-purpose engine with a carburetor, comprising: a section; and two passages partitioned by the partition so that the passage area is the same.