JP2001027155A - Engine with carburetor - Google Patents

Abstract

(57) [Summary] [Problem] To perform an engine stop operation so that the engine can be stopped immediately. SOLUTION: A mixing body (4) of a vaporizer (2).
A throttle valve (8) is disposed inside the mixing body (4), and a throttle port (2) of a slow system fuel supply passage (25) is provided near the throttle valve (8) on the inner wall of the mixing body (4).
6) and an idle port (27) are arranged. The full throttle opening means (41) detects that the key switch (45) has been turned to the OFF position for the operation of stopping the engine, and forcibly brings the throttle valve (8) into the fully open state based on the detection.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an engine with a carburetor such as a gasoline engine.

[0002]

2. Description of the Related Art As shown in FIGS. 3A and 3B, a throttle valve (8) is arranged in a mixing body (4), and a vaporizer is provided on the inner wall of the mixing body (4). A slow fuel supply passage near the throttle valve (8)
Slow port (26) and idle port (2
7) is arranged. When idling when the throttle valve (8) is almost fully closed or at a low speed when the opening of the throttle valve (8) is small, a high negative pressure generated in the gap between the inner wall of the mixing body (4) and the throttle valve (8). The fuel is sucked into the mixing body (4) from the outlets (26) and (27) of the slow system fuel supply passage (25) by pressure so as to maintain idle rotation and low speed rotation.

[0003]

2. Description of the Related Art In the above-described engine, the piston continues to move up and down by inertia immediately after the engine is stopped by a key switch, a stop switch, or the like, so that air is taken into the cylinder. . For this reason,
After the engine is stopped, especially after the engine is stopped in an idling state, the outlet of the slow system fuel supply passage (25) is exposed to a high negative pressure in the gap between the mixing body (4) and the throttle valve (8).
(26) Fuel is sucked out from (27) and flows into the cylinder. As a result, the fuel is spontaneously ignited by the high-temperature portion remaining in the cylinder, and the engine does not stop immediately despite the operation of stopping the engine.

As a countermeasure, a slow fuel supply passage (2
In some cases, a fuel cutoff valve is provided in 5), and the fuel cutoff valve is closed at the same time as the operation of stopping the engine to shut off the slow system fuel supply passage (25).

[0005]

However, even when the fuel cutoff valve is closed, fuel remains from the fuel cutoff valve to the outlets (26) and (27) of the slow fuel supply passage (25). For this reason, the residual fuel is sucked out after the engine stops and flows into the cylinder, and the engine does not stop immediately because of the residual fuel.

According to the present invention, when the engine is stopped,
The purpose is to allow the engine to stop immediately. Another object of the present invention is to make it possible to easily arrange a configuration in which the engine can be immediately stopped.
Another object of the present invention is to achieve power saving in a configuration in which the engine can be immediately stopped.

[0007]

Means for Solving the Problems [Invention of claim 1] The invention of claim 1 is, for example, shown in FIG.
As shown in FIG. A throttle valve (8) is arranged in the mixing body (4), and outlets (26) and (27) of a slow system fuel supply passage (25) are provided near the throttle valve (8) on the inner wall of the mixing body (4). An engine with a carburetor is provided with a throttle fully opening means (41) for detecting an operation of stopping the engine and forcibly opening a throttle valve (8) based on the detection of the operation.

[Invention of claim 2] The invention of claim 2 is the same as the above-mentioned invention of claim 1, but further configured as follows. The throttle fully open means (41) has a throttle drive solenoid (42), and when the operation of stopping the engine is detected, the governor lever (36) is driven to the throttle fully open side by the rod (44) of the solenoid (42). It is configured so that

[Invention of claim 3] The invention of claim 3 is the same as the above-mentioned invention of claim 1 or 2, but further configured as follows. The throttle fully open means (41) drives the throttle drive solenoid (42) for a certain period of time from when the operation of stopping the engine is detected to drive the throttle valve.
(8) is configured to be fully opened.

[0010]

[Operation and Effect of the Invention] [Claim 1] The invention of the above-mentioned claim 1 has the following operation and effect. That is, when the engine speed is in the middle / high speed range, a negative pressure corresponding to the opening degree of the throttle valve (8) is generated in the venturi section (6) in the mixing body (4). The fuel amount ejected from the main nozzle (12) is supplied to the cylinder as an air-fuel mixture.

When the engine is idling, the throttle valve (8) is almost fully closed, and when the engine speed is in a low speed range, the opening of the throttle valve (8) becomes small. In these cases, while the amount of fuel ejected from the main nozzle (12) becomes extremely small, the slow system fuel supply passage is formed due to the high negative pressure generated in the gap between the inner wall of the mixing body (4) and the throttle valve (8). Fuel is drawn into the mixing body (4) from the outlets (26) and (27) of (25) and supplied to the cylinder as an air-fuel mixture.

On the other hand, when the operation of stopping the engine is performed by the key switch (45) or the stop switch, the throttle fully opening means (41) detects the operation of stopping the engine and forcibly operates the throttle valve (8). Fully open state [state shown by a two-dot chain line in FIG. 1]. Thus, even if the intake is performed by the up-and-down movement due to the inertia of the piston after the operation of stopping the engine, the inner wall of the mixing body (4) and the throttle valve (8)
The negative pressure generated in the gap becomes small, and it becomes difficult for the fuel to be sucked out from the outlets (26) and (27) of the slow fuel supply passage (25). That is, even if the intake is performed by the inertia of the piston, almost no fuel is supplied into the cylinder, so that the engine stops immediately after the operation of stopping the engine. As a result, unnecessary fuel consumption can be reduced,
Reliability of engine operation is improved.

[Claim 2] The invention of claim 2 has the following functions and effects in addition to the functions and effects of the invention of claim 1.
It works. The governor lever (36) of the speed governor (33) swings to a position where the governor force generated by the rotation of the engine and the biasing force of the governor spring (37) are balanced, and the throttle is opened to an opening corresponding to the swing. The valve (8) is adjusted. When the engine is stopped, the throttle is fully opened.
The governor lever (36) is driven toward the throttle fully open side by the rod (44) of the throttle drive solenoid (42) of (41).

That is, the solenoid (42) is connected to the vaporizer (2).
, The rod (44) of the throttle driving solenoid (42) may be directly connected to the valve shaft (34) of the throttle valve (8) of the carburetor (2).
Is difficult to attach to the vaporizer (2). On the other hand, the governor lever (36) is attached to the side of the engine body (1), and the solenoid (42)
Can be relatively easily arranged. That is, the governor lever (36) can be effectively used to easily attach the throttle fully open means (41) to the engine.

[Claim 3] The invention of claim 3 has the following functions and effects in addition to the functions and effects of the invention of claim 1 or 2. Throttle drive solenoid (42)
However, by driving the solenoid (42) for a certain period of time after detecting the operation of stopping the engine, the power for driving the solenoid (42) can be reduced by the amount of time required to drive the solenoid (42). .

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of an engine with a carburetor according to the present invention will be described below with reference to FIGS. FIG. 1 is a schematic configuration diagram showing a main part of the vaporizer,
FIG. 2 is a side view showing a main part of the engine. FIG.
3A is a longitudinal sectional view of the vaporizer, and FIG. 3B is a sectional view taken along line BB in FIG. 3A.

In the engine, as shown in FIG. 2, an air-fuel mixture outlet side of a carburetor (2) is connected to an intake port (not shown) provided in the engine body (1). Tableware (2)
Is connected to an air cleaner (3). The intake port is connected to a cylinder [not shown] in the engine body (1). Then, the outside air is sucked into the carburetor (2) through the air cleaner (3), and is mixed with the fuel in the carburetor (2), and the mixture is supplied into the cylinder.

That is, as shown in FIGS. 3A and 3B, the vaporizer (2) is configured as follows. The vaporizer (2)
Has an intake passage (5) provided laterally in the mixing body (4), and a venturi section (6) is provided in the middle of the intake passage (5). A choke valve (7) is provided on the upstream side of the flow path of the venturi section (6) (left side in FIG. 3A), and the choke valve (7) is provided on the downstream side of the flow path of the venturi section (6). In the right], a throttle valve (8) is provided.

A nozzle mounting cylinder (9) extends downward from the venturi section (6), and a cylindrical main nozzle (12) is inserted into the nozzle mounting cylinder (9). is there. On the other hand, a float chamber (13) is arranged below the mixing body (4), and a float chamber (14) is formed in the float chamber (13). The float room (14)
There is a float (15) inside, and the float (15)
Thus, the needle valve (16) is operated. The needle valve (16) opens and closes a fuel supply path (17). The fuel supply path (17) transfers fuel from a fuel tank (not shown) into the float chamber (14). Is to lead to. Then, the needle valve (16) opens and closes the fuel supply path (17) according to the height of the float (15), so that the fuel level in the float chamber (14) is maintained at a constant level.

A fuel inlet (18) is provided at a lower portion of the nozzle mounting tube (9), and the float chamber (14) and the inside of the nozzle mounting tube (9) are connected through the fuel inlet (18). Is in communication. Further, a main jet (20) is disposed at the lower end of the passage (19) in the nozzle of the main nozzle (12), and through the main jet (20), the passage (19) in the nozzle and the nozzle mounting tube ( 9) is communicated with the lower part. Furthermore, a plurality of air ports (21) are provided on the peripheral wall of the main nozzle (12),
A main air bleed passage (24) is provided between the air ports (21) and the upstream side of the flow path of the venturi section (6) in the mixing body (4).

On the other hand, near the throttle valve (8) on the inner wall of the mixing body (4), a slow fuel supply passage (2) is provided.
Slow port (26) and idle port (27) which are exits of 5)
Are provided respectively. The slow fuel supply passage (2
5) is communicated with the nozzle passage (19) of the main nozzle (12) through a fuel distribution hole (28) provided in the main nozzle (12). A pilot jet (29) is arranged in the middle of the slow system fuel supply passage (22), and a pilot air bleed passage (30) is provided in the pilot jet (29).
Is connected to one end. The other end of the pilot air bleed passage (30) is connected to the upstream side of the flow path of the venturi (6) in the mixing body (4).

The speed of the engine of the throttle valve (8) is kept constant by a speed control device (33). That is, the valve shaft (34) of the throttle valve (8) is
As shown in the figure, the governor lever (36) of the governor (33) is connected via the connecting rod (35), and the governor lever (3
6), the governor lever (38) via the governor spring (37)
Are connected. The urging force of the governor spring (37) is adjusted by the speed control lever (38).

The governor lever (36) is configured so that governor force generated by rotation of a governor weight (not shown) is transmitted through a governor sleeve (not shown). The governor weight rotates in conjunction with the crankshaft. Thus, the governor lever (36) swings to a position where the biasing force of the governor spring (37) and the governor force are balanced, and the opening of the throttle valve (8) is adjusted according to the swing.

Further, the engine is provided with a throttle fully opening means (41) for fully opening the throttle valve (8) when the engine is stopped. That is, the throttle fully open means
As shown in FIG. 1, the solenoid (41) has a throttle driving solenoid (42) and a control unit (43), and the solenoid (4
The rod (44) of (2) is connected to the governor lever (36). The control section (43) detects that the key switch (45) has been switched to the OFF position and detects the engine stop. Then, the control unit (43) controls the solenoid (4
2) is driven so that the throttle valve (8) is fully opened.

With the above configuration, the vaporizer (2) operates as follows. That is, when the engine speed is set to the middle / high speed range by the speed control lever (38), the governor lever (36) swings at a position where the biasing force of the governor spring (37) and the governor force are balanced. The opening of the throttle valve (8) is adjusted. Then, a negative pressure corresponding to the opening of the throttle valve (8) is generated in the venturi section (6), and a fuel amount corresponding to the negative pressure is ejected from the main nozzle (12). In other words, the governor lever (36) swings in response to load fluctuations and the like, whereby the amount of fuel ejected from the main nozzle (12) is adjusted, and the engine speed set by the governing lever (38) is maintained. Is done.

On the other hand, when idling is set by the speed control lever (38), the throttle valve (8) is almost fully closed, and the engine speed is set to a low speed range by the speed control lever (38). In this case, the opening of the throttle valve (8) becomes small. In these cases, while the amount of fuel injected from the main nozzle (12) is extremely small, the mixing body
Due to the high negative pressure generated in the gap between the inner wall of (4) and the throttle valve (8), the mixing body (4) is moved from the slow port (26) or idle port (27) of the slow system fuel supply passage (25).
The fuel is sucked in, and idle rotation and low-speed rotation are maintained.

On the other hand, when the key switch (45) is switched to the OFF position, the control unit of the throttle fully open means (41)
(43) detects the switching, drives the throttle drive solenoid (42) for a certain period of time from the detection, and swings the governor lever (36), thereby forcing the throttle valve (8). To the fully open state [state of the two-dot chain line diagram in FIG. 1].

As a result, even if intake is performed by the vertical movement of the piston after the operation of stopping the engine, the negative pressure between the inner wall of the mixing body (4) and the throttle valve (8) becomes small, Slow port (26) and idle port (27)
Makes it difficult for fuel to be sucked out. In other words, even if intake is performed by the inertia of the piston, it is difficult to supply fuel into the cylinder.
The engine stops immediately.

The throttle driving solenoid (42)
The rod (44) can freely move when not driven by the control unit (43). This prevents the rod (44) from hindering the swing of the governor lever (36) during engine operation.

The above embodiment can be modified as follows. That is, in the above description, the throttle valve (8) is fully opened through the governor lever (36). However, the present invention is not limited to this. For example, the throttle valve (8) may be connected to the valve shaft (34) of the throttle valve (8). , Throttle drive solenoid (42) rod (4
4) may be directly connected to drive the throttle valve (8). Further, in the above description, the control unit (43) detects that the key switch (45) has been switched to the OFF position and detects that the engine has stopped. However, the present invention is not limited to this. It may be configured to detect that the ignition of the spark plug has stopped and detect the stop of the engine.

Further, in the above description, the throttle fully open means (41) drives the throttle drive solenoid (42) for a certain period of time after the detection of the engine stop to operate the throttle valve.
Although (8) is fully opened, the present invention is not limited to this. For example, the throttle drive solenoid (42) is driven to operate the throttle valve (8) from the detection of the engine stop to the start of the engine. May be fully opened. Further, it is needless to say that the present invention is applicable to an engine having no governing device (33).

[Brief description of the drawings]

FIG. 1 shows an embodiment of an engine with a carburetor according to the present invention, and is a schematic configuration diagram showing a main part of the carburetor.

FIG. 2 is a side view showing a main part of the engine.

3 (A) is a longitudinal sectional view of the vaporizer, and FIG. 3 (B) is a sectional view taken along line BB in FIG. 3 (A).

[Explanation of symbols]

4 ... mixing body, 8 ... throttle valve, 25 ... slow system fuel supply passage, 26 ... slow port, 27 ... idle port, 33 ... governor lever, 36 ... governor lever, 41 ... throttle fully open means, 42 ... throttle drive solenoid , 43… Throttle drive solenoid rod.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02D 41/04 310 F02D 41/04 310H 41/22 310 41/22 310E F02M 3/02 F02M 3/02 A 3/045 3/045 AQ F term (reference) 3G065 CA09 DA07 DA09 EA06 GA00 GA46 HA02 JA02 JA11 JA16 KA05 3G092 AA01 AB02 BA02 DC01 DG03 DG09 EA17 EA21 EA25 FA28 GA10 HA05X HA08X HF20Z 3G301 LA01 JA01 PF01

Claims (3)

[Claims] 1. A throttle valve in a mixing body (4).
(8), and a slow fuel supply passage near the throttle valve (8) on the inner wall of the mixing body (4).
In the engine with a carburetor provided with the outlets (26) and (27) of (25), a throttle fully opening means for detecting an operation of stopping the engine and forcibly opening the throttle valve (8) based on the detection. An engine with a carburetor, comprising: (41). 2. The engine with a carburetor according to claim 1, wherein the throttle valve (8) is a governor lever of a governor (33).
The throttle fully opening means (41) has a throttle drive solenoid (42), and when the operation of stopping the engine is detected, the throttle (41) is actuated by the rod (44) of the solenoid (42). An engine with a carburetor, characterized in that the governor lever (36) is driven to the fully open side of the throttle. 3. The engine with a carburetor according to claim 2, wherein the throttle full-opening means (41) drives the throttle driving solenoid (42) for a certain period of time after detecting the operation of stopping the engine. An engine with a carburetor, wherein the throttle valve (8) is fully opened.