JPS624667Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a low-speed system of a carburetor that supplies the fuel necessary for engine starting and idling.

The low-speed system of the carburetor includes a low-speed jet, a low-speed air bleed jet, and a low-speed economizer in the low-speed fuel passage from the constant oil level chamber through the main jet to the slow port upstream of the fully closed throttle valve and the idle port downstream. The engine required mixture ratio during idling, which is determined by the engine's tappet clearance, engine temperature, engine compression pressure, variations in the low-speed system itself, etc., is determined by adjusting the effective area of the idle port using the needle valve at the tip of the screw. In addition, the mixture of fuel and air in the low-velocity fuel passage can be adjusted by means of an adjusting screw. However, since these adjustment screws are exposed outside the carburetor, anyone can freely touch them, and they cannot be accessed by anyone during the process of manufacturing the carburetor, assembling it into an engine, installing it in a car, etc., or after assembly is completed. Even if a person uses various measuring instruments to obtain the optimum mixture ratio for each engine and adjusts the amount of harmful substances in the exhaust to a small amount, an unskilled person may touch the mixture ratio and adjust the exhaust to the engine. This caused the engine to become inoperable and the exhaust gas purification system to be damaged.
For this reason, it is common practice to install an idle limiter on the adjustment screw of the idle port so that once it has been adjusted, it cannot be turned beyond a certain angle, but the adjustment screw is small in diameter and requires delicate adjustment. If you turn it even slightly, it will upset the idle mixture.

The present invention is a carburetor equipped with a main body provided with a constant oil level chamber and a bench lily, and an air horn connected to the main body to form an air inlet. The needle valve part of the adjustment screw provided at the top of the carburetor is exposed, and there is no adjustment screw exposed outside the carburetor, which cannot be touched unless the air horn is removed and disassembled. By creating an impossible structure, we solved the problems mentioned above.

An example of the present invention will be explained below with reference to the drawings.
1 is an air horn, 2 is a main body, and 3 is a flange, which are connected and fixed to each other with bolts. Reference numeral 4 denotes a low-speed fuel passage, and a slow port 10 branches from the main fuel passage 8 that runs from the constant oil level chamber 5 through the main jet 6 to the main nozzle 7 and opens slightly upstream of the fully closed throttle valve 9. and an idle port 11 which opens slightly downstream, and a low speed jet 12, a first low speed air bleed jet 1.
3, a low speed economizer jet 14, and a second low speed air bleed jet 15. The air horn 1 is equipped with an air purifier (not shown) and has a choke valve, and the main body 2 has a constant oil level chamber 5 and a bench lily 16.

In the embodiment shown in FIG.
8 into this screw seat 17 to attach the tip needle valve part 19.
is inserted so as to face the first low-speed air bleed jet 13.

In the embodiment shown in FIG. 2, a screw seat 20 is provided protrudingly from the portion of the main body 2 covered with the air horn 1, and an adjustment screw 21 is screwed into this screw seat 20 to open the tip needle valve portion 22. It is inserted so as to face the second low-speed air bleed jet 15.

In all of these embodiments, prior to assembling the air horn 1 to the main body 2, the adjusting screws 18, 21 are turned to move the tip needle valve parts 19, 22 in and out, and the low speed air bleed jets 13, 15 are adjusted. Although the effective area is adjusted, the air horn 1 may be removed and adjusted during a trial run after being assembled into an engine or installed in a car, and in any case, the carburetor manufacturer or car manufacturer Adjustments are made by the contractor. The first and second low-speed air bleed jets 13 and 15 are made to have a diameter that regulates the leanest side of the required mixture ratio during idling, and by narrowing them down, the amount of air bleed is brought up to the limit on the richest side. can be restricted.

Depending on the arrangement and direction of the low-speed fuel passage 4, the low-speed economizer jet 4 may have a needle valve portion at the tip of the adjustment screw.

As described above, the adjustment screw that adjusts the engine required mixture ratio at idling according to variations in the carburetor, engine conditions, etc. is not exposed to the outside of the carburetor, but is covered with an air horn, and the jet in the low-speed fuel passage is used. According to this proposal, the required mixture ratio can be obtained by adjusting the effective area of the exhaust gas. Once adjusted to minimize material and covered with the air horn, it is impossible to access the adjustment screws without removing and disassembling the air horn, and therefore it is impossible for unskilled personnel to arbitrarily adjust the adjustment screws. This completely eliminates inconveniences such as turning the mixture ratio out of order to the extent that it makes the engine inoperable, and increasing harmful substances in the exhaust gas to the extent that it damages the exhaust gas purification device. Furthermore, if the adjustment screw for the low-speed system, which has a small diameter and requires delicate adjustment, such as the conventional idle limiter, can be rotated within a certain range, there is a risk that the idle mixture will be distorted. According to the article, since it is impossible to touch the adjustment screw from outside the carburetor, stable idling can be achieved at all times.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view showing an embodiment of the present invention, and FIG. 2 is a partial vertical cross-sectional view of a different embodiment. 1... Air horn, 2... Main body, 3... Flange, 4... Low speed fuel passage, 5... Constant oil level chamber, 1
3...First low speed air bleed jet, 14...
Low speed economizer jet, 15... Second low speed air bleed jet, 16... Bench lily, 17
...Screw catch, 18...Adjustment screw, 19...Tip needle valve section, 20...Screw catch, 21...Adjustment screw,
22...Tip needle valve part.

Claims (1)

[Scope of utility model registration request] In a carburetor comprising a main body 2 having a constant oil level chamber 5, a bench lily 16, and an air horn 1 connected thereto forming an air inlet, a low-velocity fuel passage 4 is provided.
Air is supplied to jets 13, 14, and 15 provided in
An adjustment screw 18 provided in the part covered by the horn 1,
The low-speed system is characterized in that the tip needle valve parts 19 and 22 of 21 are exposed and there is no adjustment screw exposed outside the carburetor.