JP2002098003A - Fuel cut device for gasoline engine carburetor when engine is stopped - Google Patents

Abstract

(57) [Summary] Immediately after an engine stop operation, the engine stop delay caused by suction of residual gasoline in a main nozzle into a venturi chamber is eliminated and the engine is immediately stopped. SOLUTION: An intake passage 9 is communicated with a float chamber 3 of a carburetor 2 of a gasoline engine 1 through a fuel cut valve 4. When the operation of the engine 1 is stopped, the fuel cut valve 4 is opened to make the float chamber 3 a negative pressure with the negative pressure of the intake passage 9 so that the main nozzle 6 communicating with the float chamber 3 is opened. A negative pressure is applied to prevent gasoline in the main nozzle 6 from being sucked into the venturi chamber 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine stop fuel cut device for a carburetor of a gasoline engine.

[0002]

2. Description of the Related Art As a fuel cut device at the time of engine stop of a carburetor of a gasoline engine, there is a prior art device configured as follows. That is, the inlet of the main nozzle of the vaporizer is configured to be openable and closable by the fuel cut valve. When the engine is stopped, the fuel cut valve closes the entrance of the main nozzle so that the fuel in the float chamber does not flow into the main nozzle.

[0003]

The above prior art has the following problems. [ I. Immediately after the operation of stopping the operation of the engine, the stoppage of the engine is delayed by an amount corresponding to the gasoline remaining in the main nozzle being sucked into the venturi chamber. ]

When the engine is stopped, the fuel cut valve closes the inlet of the main nozzle to prevent the float and the fuel in the room from flowing into the main nozzle. However, there is a problem that the gasoline remaining in the main nozzle is sucked out into the venturi chamber, the rotation of the engine is maintained by the amount of the remaining gasoline, and the stop of the engine is delayed immediately after the operation of stopping the operation of the engine.

An object of the present invention is to make the following. (I). Immediately after the operation of stopping the engine, the delay in stopping the engine due to the suction of the residual gasoline in the main nozzle into the venturi chamber is eliminated, and the engine is immediately stopped.

(B). The structure of the negative pressure source for immediately stopping the engine is simplified, and the manufacturing cost is reduced. (C). The length of a dedicated passage of the negative pressure introduction passage for immediately stopping the engine is shortened, and the additional processing cost of the dedicated passage is reduced.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a fuel cut-off device for a carburetor of a gasoline engine according to the present invention, as shown in FIG. 1, FIG. 2 or FIG. It is characterized by having such a configuration.

FIGS. 1 and 2 show a first embodiment of a fuel cut-off device for a carburetor of a gasoline engine when the engine is stopped according to the present invention. FIG. 1 is a system diagram of an intake passage and a fuel passage of the carburetor, and FIG. It is a cross-sectional plan view of a container. FIG. 3 is a system diagram of an intake passage and a fuel passage of a carburetor according to a second embodiment of the present invention.

○ Invention 1. Claim 1. 1 and 2,
Or see FIG. A negative pressure source (5) is connected to a float chamber (3) of a carburetor (2) of a gasoline engine (1) via a fuel cut valve (4).
During operation of the engine (1), the fuel cut valve (4) is kept closed.

When the operation of the engine (1) is stopped, the fuel cut valve (4) is opened, and the negative pressure of the negative pressure source (5) is applied to the float chamber (3). Thereby, the inside of the main nozzle (6) communicating with the inside of the float chamber (3) is set to a negative pressure,
It is characterized in that gasoline in the main nozzle (6) is not sucked into the venturi chamber (7).

○ Invention 2. Claim 2. 1 and 2,
Or see FIG. The fuel cut-off device for a gasoline engine carburetor according to the first aspect of the present invention is characterized in that the following configuration is added. The negative pressure source (5) is constituted by the intake passage (9) of the engine (1) located downstream of the throttle valve (8) of the carburetor (2). The float chamber (3) communicates with an intake passage (9) via a fuel cut valve (4).

○ Invention 3. Claim 3. See FIG. 1 and FIG. The fuel cut-off device for a gasoline engine carburetor according to the first or second aspect of the present invention is characterized in that the following configuration is added. A negative pressure source (5) is communicated with the float chamber (3) of the vaporizer (2) through a negative pressure introduction path (13) and a fuel cut valve (4) in order. A float chamber is provided in the entrance chamber (11) on the upstream side of the venturi chamber (7) of the vaporizer (2).
(3) is communicated through the same pressure communication passage (12). A part of the same pressure communication path (12) is also used as a part of the negative pressure introduction path (13).

[0013]

The fuel cut-off device for the gasoline engine carburetor according to the present invention at the time of engine stop has the following effects. ○ Invention 1. Claim 1. See FIG. 1, FIG. 2, or FIG. 1 and 2 show a first embodiment of a fuel cut-off device for a gasoline engine carburetor when the engine is stopped according to the present invention. FIG. 1 is a system diagram of an intake passage and a fuel passage of the carburetor, and FIG. It is a top view. FIG. 3 is a system diagram of an intake passage and a fuel passage of a carburetor according to a second embodiment of the present invention.

[A. Immediately after the stop operation of the engine, the amount of gasoline remaining in the main nozzle (6) is no longer sucked into the venturi chamber (7). The engine (1) is immediately stopped. ]

When the operation of the engine (1) is stopped, the fuel cut valve (4) is opened. Then, the negative pressure of the negative pressure source (5) makes the float chamber (3) negative pressure, the inside of the main nozzle (6) communicating with the float chamber (3) becomes negative pressure, and the inside of the main nozzle (6) becomes negative. Gasoline is sucked out to the float chamber (3) side against the negative pressure of the venturi chamber (7), and is not immediately sucked into the venturi chamber (7).

Therefore, immediately after the operation of stopping the operation of the engine, the gasoline remaining in the main nozzle (6) remains in the main nozzle (6) as much as the gasoline remaining in the venturi chamber (7) is no longer sucked. The problem of the prior art that the engine stop is delayed when gasoline is sucked into the venturi chamber (7) can be solved and the engine (1) can be stopped immediately.

○ Invention 2. Claim 2. 1 and 2,
Or see FIG. [B. The negative pressure source (5) for immediately stopping the engine (1) is simplified in its configuration by the amount that the engine (1) also serves as the intake negative pressure of the existing intake passage (9), and its production is simplified. Costs can be reduced. ○ Invention 3. Claim 3. See FIG. 1 and FIG.

[C. Only a part of the negative pressure introduction path (13) for stopping the engine (1) is used as a part of the same pressure communication path (12). By reducing the length, the additional processing cost for forming a dedicated passage for the negative pressure introduction passage (13) can be reduced. ]

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a fuel cut-off device for a carburetor of a gasoline engine according to the present invention will be described below with reference to the drawings.

Embodiment 1 Claims 1, 2, 3.
See FIG. 1 and FIG. 1 and 2 show a first embodiment of a fuel cut-off device for a gasoline engine carburetor when the engine is stopped according to the present invention. FIG. 1 is a system diagram of an intake passage and a fuel passage of the carburetor, and FIG. It is a top view.

In FIG. 1, reference numeral (1) denotes a gasoline engine, (21) denotes a cylinder, and (22) denotes a piston. (2) is a vaporizer, (3) is a float chamber, (23) is a float valve, and (24) is a float. (6) is a main nozzle, (25) is a slow port, (26) is an idle port, (27) is a main air bleed, and (28) is a pilot air bleed.

(29) is a magnet type ignition device, (30) is an ignition plug, and (31) is an engine stop switch. (32) is a fuel cut command switch, (33) is a battery, and (34) is an off timer.

As shown in FIGS. 1 and 2, a negative pressure source is supplied to a float chamber (3) of a carburetor (2) of a gasoline engine (1) via a fuel cut valve (4) composed of an electromagnetic valve. (5) is communicated. When operating the engine (1), this fuel cut valve
(4) is kept closed.

When the operation of the engine (1) is stopped, the fuel cut valve (4) is opened, and the negative pressure of the negative pressure source (5) is applied to the float chamber (3). Thereby, the inside of the main nozzle (6) communicating with the inside of the float chamber (3) is set to a negative pressure,
The gasoline in the main nozzle (6) is configured not to be sucked into the venturi chamber (7).

The negative pressure source (5) is constituted by the intake passage (9) of the engine (1) located downstream of the throttle valve (8) of the carburetor (2). Float chamber (3) with fuel cut valve
It communicates with the intake passage (9) through (4).

A negative pressure source is connected to a float chamber (3) of the vaporizer (2) through a negative pressure introducing passage (13) and a fuel cut valve (4) in order.
(5) is communicated. Venturi room of this vaporizer (2)
The float chamber (3) communicates with the inlet chamber (11) on the upstream side of (7) through the same pressure communication passage (12). A part of the same pressure communication path (12) is also used as a part of the negative pressure introduction path (13).

In FIG. 2, reference numeral 36 denotes a negative pressure introducing jet, which is detachably screwed to an intermediate portion of the negative pressure introducing passage 13 so that the fuel cut valve 4 can be opened and closed. To close the valve. The jet hole diameter of the negative pressure introducing jet (36) is selected according to the size of the vaporizer (2).

When the engine (1) is stopped, the engine stop switch (29) is turned on, the magnetic ignition device (29) is grounded, and the ignition of the spark plug (30) is stopped.
Stop the engine (1). This engine stop switch
In conjunction with the turning on of (29), the fuel cut command switch (32) is turned on and the off timer (34) is started, and at the same time, the fuel cut valve (4) is opened to open the intake passage (9). The fuel in the main nozzle (6) is sucked back into the float chamber (3) by the negative pressure, and this fuel is prevented from being sucked out to the venturi chamber (7).

When the engine (1) stops sufficiently, the intake passage
After the negative pressure in (9) disappears, the off-timer (34) ends the timing operation, closes the fuel cut valve (4), and prepares for the next start of the engine.

Embodiment 2 Claims 1.2. FIG.
reference. FIG. 3 shows a second embodiment of the present invention.
It is a system diagram of a fuel passage. In the second embodiment, a part of the configuration of the first embodiment is changed as follows.

That is, the same pressure communication passage (12) in FIG.
Change to the middle air passage (35). Thereby, the float chamber (3) is stopped from communicating with the entrance chamber (11) of the vaporizer (2), and is changed to communicate with the atmosphere.

[Brief description of the drawings]

FIG. 1 and FIG. 2 show a first embodiment of a fuel cut-off device for an engine stop of a carburetor of a gasoline engine according to the present invention. FIG. 1 is a system diagram of an intake passage and a fuel passage of a carburetor.

FIG. 2 is a cross-sectional plan view of a vaporizer.

FIG. 3 shows an intake passage of a carburetor according to a second embodiment of the present invention.
The system diagram of a fuel passage.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Gasoline engine, 2 ... Vaporizer, 3 ... Float chamber, 4 ... Fuel cut valve, 5 ... Negative pressure source, 6 ... Main nozzle, 7 ... Venturi chamber, 8 ... Throttle valve, 9 ... Intake passage, 11 ... Entrance room, 12: same pressure communication passage, 13: negative pressure introduction passage.

Claims (3)

[Claims] A negative pressure source (5) is provided to a float chamber (3) of a carburetor (2) of a gasoline engine (1) via a fuel cut valve (4).
The fuel cut valve (4) is kept closed when the engine (1) is operating, and the fuel cut valve (4) is opened when the operation of the engine (1) is stopped. Float chamber with negative pressure of pressure source (5)
By making (3) a negative pressure, the inside of the main nozzle (6) communicating with the inside of the float chamber (3) is made a negative pressure,
(6) A fuel cut-off device for a gasoline engine carburetor, wherein gasoline in the (6) is not sucked into the venturi chamber (7). 2. An engine stop fuel cut device for a carburetor of a gasoline engine according to claim 1, wherein the intake passage of the engine (1) is located downstream of the throttle valve (8) of the carburetor (2). (9) The negative pressure source (5) is constituted, and the float chamber (3) is connected to an intake passage (9) via a fuel cut valve (4). 3. The fuel cut-off device for a gasoline engine carburetor according to claim 1 or 2, wherein a negative pressure introducing passage (13) is provided to a float chamber (3) of the carburetor (2). A negative pressure source (5) is communicated through the valve (4) in order, and a float chamber (3) is connected to the inlet chamber (11) on the upstream side of the venturi chamber (7) of the vaporizer (2) under the same pressure. A communication is established through a passage (12), and a part of the same pressure communication passage (12) is also used as a part of a negative pressure introduction passage (13).