JPS6183477A - Action control device of carburetor - Google Patents

Abstract

PURPOSE:To obtain the opening of a secondary side throttle valve in accordance with the temperature of an engine, by providing a passage introducing the atmosphere through a valve, which changes its opening characteristic in accordance with a temperature, in a passage of resultant Venturi negative pressure opening the secondary side throttle valve. CONSTITUTION:A diaphragm device 8, actuated by introducing through a pipe 10 the resultant negative pressure generated by the Venturi negative pressure in a primary side passage 5 and a secondary side passage 7, opens and closes a secondary side throttle valve 6. The atmospheric pressure, being introduced by a pipe 11 to the pipe 10, is regulated by a valve 12 whose opening is controlled by a temperature sensing member 15 provided in a cooling water jacket 14. The temperature sensing member 15, changing its expansion characteristic in accordance with a temperature and rapidly expanding at 30-40 deg.C, prevents a lean state by decreasing an opening of the secondary side throttle valve 6 at a temperature of said degree or less while increases an intake quantity by increasing the opening at a temperature of said degree ore more.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention mainly relates to an operation control device for a carburetor provided on the intake side of a vehicle engine.

(Prior art) As a conventional device of this kind, for example, Utility Model Application No. 59-99139
As seen in the figure, a primary passageway having a primary throttle valve and a secondary passageway having a secondary throttle valve are arranged side by side in the carburetor main body connected to the intake side of the engine, and the secondary throttle valve The valve is equipped with a negative pressure actuator that controls the opening and closing of the valve, and a negative pressure passage is opened in the negative pressure chamber of the actuator to introduce the combined venturi negative pressure of both passages, and an atmospheric passage that communicates the inside of the passage with the atmosphere is connected to the engine. The secondary throttle valve is equipped with an opening/closing valve that responds to the temperature of the engine, so that the secondary throttle valve opens rapidly and widely during acceleration operations during warm-up of the engine (preventing changes in drivability due to this). However, in this case, the opening/closing valve is generally a one-stage variable type in which the degree of opening changes approximately uniformly from the low temperature range to the high temperature range.
Such a method has the disadvantage that it cannot sufficiently correct the deterioration of drivability.

(Problems to be Solved by the Invention) An object of the present invention is to provide a device that is free from such inconveniences, that is, a device that prevents deterioration of drivability as much as possible.

(Means for Solving the Problems) The present invention has been made based on the above viewpoint, and includes a primary passage having a primary throttle valve and a secondary throttle valve in the carburetor main body connected to the intake side of the engine. A negative pressure passage is provided in parallel with a secondary passage having a valve, and the secondary throttle valve is equipped with a negative pressure actuator for controlling the opening and closing of the secondary throttle valve, and the combined venturi negative pressure of both passages is introduced into the negative pressure chamber of the actiniator. In a type in which the atmospheric passage that communicates the inside of the negative pressure passage with the atmosphere is provided with an on-off valve that responds to the temperature of the engine, the on-off valve has a relatively slow opening change in a low temperature range, and a relatively slow change in opening in a high temperature range. In this case, the opening is configured in a multi-stage variable type that produces a relatively rapid change in opening degree.

(Example〕 An example of implementing the present invention will be explained with reference to the attached drawings.

In the drawing, (1) shows the intake passage extending from the engine, (2) shows the main body of the carburetor on the upstream side leading to this, and the main body (2)
) has an upstream choke valve (3) and a downstream primary throttle valve (4) in the primary passage (5J) and the secondary throttle valve (6).
), and the secondary throttle valve (6) is equipped with a negative pressure actuator (8) for controlling the opening and closing of the secondary throttle valve (6), and a negative pressure chamber (9) therein is provided. Both aisles +
51 (opens a negative pressure passage a [that leads to a composite negative pressure of the venturi negative pressure generated in An on-off valve α2 is provided that responds to the temperature of the air passage C. The on-off valve α2 is located below the atmospheric passageway (a cooling water jacket) opposite to the valve hole α3 interposed in the cooling water jacket C.
The temperature sensing part α9 at the lower end inserted in the passage 141 is operated to the upper closing side when the temperature rises, and furthermore, both passages 1
51 (The upstream end of 71 is equipped with an air cleaner αe.

Although the above is not particularly different from the conventional one, according to the present invention,
The opening/closing valve α2 is of a multi-stage variable type that causes a relatively gentle change in opening in a low temperature range below a planned intermediate temperature, for example, around 40°C, and a relatively rapid change in opening in a high temperature range higher than the intermediate temperature. I configured it.

To explain this in detail with reference to the illustrated one, the on-off valve α2 is a two-stage taper type consisting of an upper half (12&) of a relatively small taper and a lower half (j2b) of a relatively large taper. According to its upward movement as the temperature rises, the valve hole (13) facing it first opens in the upper half (13).
12a) and then a relatively rapid change in opening due to the lower half (12b). To explain further, its characteristic curve is as shown by line a and line in FIG. In the low temperature range down to -5°C, the line closes relatively slowly as shown by lJa, but in the madder temperature range higher than this temperature, for example in the high temperature range up to 50°C room temperature, the line closes relatively rapidly as shown above. It was made to close so that it was fully closed, so that an inflection point C occurred at the intermediate temperature.

(Action) Elbow 1'? I r! According to the above-mentioned two-stage characteristic of the A valve f12, the synthetic venturi negative pressure guided to the negative pressure actuator (8) is given a corresponding two-stage correction to the secondary throttle valve (6). For example, as shown in FIG. 3, the opening degree characteristic can be obtained as a two-stage variable type consisting of a line entry and an extension B, and having a bending point 0 in the middle. More specifically, the opening range of the throttle valve (6) is lower than an intermediate temperature of, for example, around 40°C.
In the low temperature range down to °C, the line A has a relatively gentle slope, and in other words, the opening can be kept to a relatively small degree.
In a high temperature range higher than this temperature, for example, up to room temperature of 50°C, a relatively steep line B is shown, in other words, a relatively large opening degree is obtained, and in response to the intermediate temperature, there is a relatively steep line B. A state having a bending point C is obtained.

In this case, it is conceivable to set the intermediate temperature to a somewhat lower temperature side, for example, 30°C or lower, and according to this, the bending point will deviate from point O to point C' and line B will become a line. B', which can be achieved by slightly changing the shape of the on-off valve α2 or the corresponding valve hole (13).

Thus, the opening characteristic of the throttle valve (6) can be obtained using a two-stage variable formula with an inflection point in the middle within a predetermined temperature range, for example, from -5°C to 50°C. A comparison with the one-stage variable type one is as follows. In other words, when the opening/closing valve a2 has a substantially uniform relationship change, the throttle valve (6
) is obtained by a substantially uniform opening characteristic as shown by mD or line E in Fig. (6) becomes a relatively wide open state, which causes the air-fuel mixture to become diluted and drivability deteriorates.

Furthermore, in the case of line E, the valve (6) cannot be opened to a predetermined large degree even at room temperature of, for example, 50° C. or higher, which also impairs drivability.

Furthermore, in order to correct this, the on-off valve α2 is set to SO at room temperature, for example.
In the case of a formula that closes suddenly at 'c', the throttle valve (6
) is a type in which, for example, the throttle valve (6) is bent from the line E to produce 8F', but this is not preferable because it involves a sudden change in the opening degree of the throttle valve (6) and causes an unexpected shock.

(Effects) As described above, according to the present invention, the temperature-responsive on-off valve provided in the atmospheric passage is a two-stage variable type that produces a relatively gentle change in opening in a low temperature range and a relatively rapid change in opening in a high temperature range. Accordingly, the opening range of the secondary throttle valve can be set to a relatively low opening in the low temperature range and a relatively high opening in the high temperature range. Various inconveniences that tend to occur with the type that changes the opening evenly, such as deterioration of drivability or occurrence of unexpected shock, can be eliminated, and the structure is simple and inexpensive. .

[Brief explanation of drawings]

FIG. 1 is a cutaway side view of an example of the device of the present invention, FIG. 2 is an opening characteristic diagram of an on-off valve, and FIG. 5 is an opening characteristic diagram of a secondary throttle valve. (1)...Intake passage (2)...Carburetor body (4)...Primary throttle valve (5)...-Next side passage (6)...Secondary throttle valve (Sword...・Secondary side passage (8)...Negative pressure actuator (9)...
・Negative pressure chamber (lot...Negative pressure passage Round...Atmospheric passage α2...Opening/closing valve (12a)...Upper half (12b)...Lower half Patent applicant Honda Motor Co., Ltd. Company, Chief Executive Officer Kin Kitamura -12
, ;, 2 people outside of lJ

Claims (1)

[Claims] A primary side passage having a primary throttle valve and a secondary side passage having a secondary throttle valve are arranged in parallel in the carburetor main body connected to the intake side of the engine, and the opening and closing of the secondary throttle valve is controlled. A negative pressure actuator is provided to open a negative pressure passage that introduces the combined bench pressure of both passages into a negative pressure chamber of the actuator, and an atmospheric passage that communicates the inside of the negative pressure passage with the atmosphere in response to the temperature of the engine. Operation control of a carburetor, in a type equipped with an on-off valve, in which the on-off valve is configured in a multi-stage variable type that causes a relatively gradual change in opening in a low temperature range and a relatively rapid change in opening in a high temperature range. Device.