JPS62135650A - Starting device for carburetor - Google Patents

Abstract

PURPOSE:To improve acceleration characteristic when an engine is in warm operation, by using slow system fuel as the starting fuel to increase its amount only when the engine is started and jetting this increased amount of fuel through a bypass in accordance with the movement of a throttle valve when the engine is accelerated. CONSTITUTION:A carburetor has a slow system passage comprising a slow system jet 1, idle hole 4, slow system air passage 5, slow system mixture passage 7, etc. Here the carburetor provides the first passage opening and closing device 10 interposing in the half way of the slow system air passage 5. This opening and closing device 10 connects its negative pressure chamber 14 communicating with a manifold 11 in the downstream of a throttle valve 21 by a negative pressure passage 15, but the carburetor provides the second passage opening and closing device 16 interposing in between the said negative pressure passage 15. And the carburetor is constituted such that said second passage opening and closing device 16, when it controls a valve 19 to be lifted against a spring 17 at starting time, introduces an intake negative pressure to the negative pressure chamber 14 to close the opening and closing device 10 and enables an increased amount of fuel to be jetted from a bypass 3 and the idle port 4.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention comprises 1. The present invention relates to a carburetor for an internal combustion engine, and particularly to a starting device for a carburetor that provides good acceleration performance during warm-up.

[Conventional technology]

In the conventional independent starting device, as described in Utility Model Application Publication No. 46-20089, the starting fuel injection port is located downstream of the throttle valve and is controlled to negative suction pressure, so During acceleration, the fuel flow rate decreased as the intake negative pressure decreased, resulting in a lean mixture ratio, leading to deterioration in drivability.

[Problem that the invention seeks to solve]

The above-mentioned conventional technology did not take into consideration the increase in fuel amount during acceleration during warm-up, resulting in a problem of deterioration of drivability.6 The purpose of the present invention is to maintain the acceleration state even during acceleration during warm-up. The aim is to increase the amount of fuel accordingly and improve drivability.

Measures to solve problem C] The above method uses slow type fuel as the starting fuel, increases the amount of this slow type fuel only at the time of starting, and uses this increased amount of fuel from the bypass to control the movement of the throttle valve during acceleration. This is accomplished by ejecting accordingly.

[Effect]

The passage opening/closing device is provided in the middle of the slow system passage, and when the suction negative pressure of the anifold is introduced, the passage opening/closing device closes the slow system passage and increases the amount of slow system fuel.

The second passage opening/closing device manually opens and closes a passage guiding suction negative pressure to the first passage opening/closing device and a passage guiding air to the anifold at the time of startup.

At startup, air flows into the anifold to activate the second passage opening/closing device, and the negative pressure inside the anifold acts on the first passage opening/closing device, closing the slow system passage, and from the bypass, The increased amount of slow system fuel is sent into the anifold.6 [Embodiment] An embodiment of the present invention will be described below with reference to FIG.

Gas vessels include slow jet and slow air bleed.2. Bypass 3. Idol Hall 4. Slow air passage 5. Slow system fuel passage6. There is a slow system passage consisting of a slow system mixture passage 7. In the middle of this slow system air passage, there is a first passage opening/closing device 10 consisting of a diaphragm As 8 and a plunger 9. Also, a passage 3 connecting the anifold 11 and the atmospheric chamber 12, and a negative pressure passage 15 connecting the negative pressure chamber 14 of the first passage opening/closing device 10 and the anifold 11.
In the middle, there is a second passage opening/closing device]6. When the second passage opening/closing device 16 is pulled up against the spring 17 at startup, the seat 18 begins to open and the necessary air is introduced from the atmospheric chamber 12 and flows into the manifold 11 simultaneously through the negative pressure passage. The valve 19 located in the middle of the air passage 15 moves, and the negative pressure of the anifold acts on the negative pressure chamber 14 of the first passage opening/closing device 10, moves the plunger 9 against the spring 20, and opens the slow air passage 5. close. As a result, the slow system mixture becomes richer, and bypass 3 and idle port 4
The fuel then flows to the anifold 11 as starting fuel.

Now, when accelerating at the time of starting, the negative pressure in the bypass 3 changes with the movement of the throttle valve 21, and the amount of starting fuel increases further.

In FIG. 2, the slow system air bleed passage 5 is branched,
A second slow air bleed passage 22 is provided, so that even if the first passage opening/closing device 10 malfunctions, the slow air bleed passage 23 allows the slow air to flow to the anifold 11.
This prevents the fuel from spewing out and making it impossible to operate.

〔Effect of the invention〕

According to the present invention, since the starting fuel is ejected from the bypass hole, the amount of starting fuel can be increased in accordance with the movement of the throttle valve during acceleration during warm-up, which has the effect of improving drivability.

[Brief explanation of drawings]

FIG. 1 is a drawing showing one embodiment of the invention, and FIG. 2 is a drawing showing another embodiment of the invention. 1... Slow type jet, 2... Slow type air bleed, 3... Bypass, 4... Idle hole, 5
... Slow system air passage, 6... Slow system fuel passage,
7... Slow system mixture passage, 8... Diaphragm 11
．． 9... Plunger, 10... First passage opening/closing device,
11... Anifold, 12... Popular room, 13...
・Passage, ]4... Negative pressure chamber, 15... Negative pressure passage, 16
...Second passage opening/closing device, 17...Spring, 18
...Seat, 19--Valve, 20...Spring, 2
DESCRIPTION OF SYMBOLS 1... Throttle valve, 22... 2nd slow system air bleed passage, 23... 1st slow system air bleed passage.

Claims (1)

[Claims] 1. In a vaporizer having a slow system, a first passage opening/closing device that opens and closes a passage to the slow system passage, a passage connecting the first passage opening/closing device and the manifold, and an atmospheric chamber and the manifold are provided. A starting device for a carburetor, characterized in that a second passage opening/closing device is provided for opening and closing the connecting passages. 2. The starting device for a carburetor according to claim 1, wherein the first passage opening/closing device is provided in the slow air bleed passage. 3. A starting device for a carburetor according to claim 2, wherein the first passage opening/closing device is provided in a second air bleed passage branching off from the slow air bleed passage.