JPH0343395Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a technique for improving a butterfly-type throttle valve installed in an intake passage of an internal combustion engine.

<Prior Art> A so-called butterfly type throttle valve as shown in FIG. 2, for example, is known as a throttle valve that is installed in an intake passage of an internal combustion engine to vary the area of the passage.

That is, the shaft member 2 is rotatably supported with the diametrical direction of a cylindrical intake passage (throttle chamber) 1 in which the flow direction of intake air is set downward substantially along the direction of gravity as a rotation axis C. . A portion (center portion) of this shaft member 2 facing into the intake passage 1 is formed to have a semicircular cross section, and a disc-shaped valve body 3 is provided on this semicircular plane portion 2a facing upstream of the intake passage 1. Fixed. As a result, the valve body 3 rotates with the end face on the downstream side of the intake passage 1 as the rotation axis C, and the butterfly type throttle valve 4 is rotated by the valve body 3 and the shaft member 2.
is configured.

This throttle valve 4 is formed so as to be in a fully closed state (including cases where a slight gap is formed) at a position inclined at a predetermined angle α with respect to a plane perpendicular to the axis of the intake passage. The passage area of the intake passage 1 is increased by rotating the valve body 3 in a direction in which the inclination increases from . In the fully closed state, the circumferential end surface 3a of the valve body 3 is aligned with the inner circumferential surface of the intake passage 1, in other words, the circumferential end surface of the valve body 3 and the inner circumferential surface of the intake passage 1 are adjacent to each other in the fully closed state. The circumferential end surface 3a of the valve body 3 is formed to be inclined at the predetermined angle α with respect to the plate thickness t direction so that the valve body 3 and the valve body 3 are parallel to each other.

By the way, in the case of a so-called single point injection system (hereinafter abbreviated as "SPI system") or a type in which fuel is supplied from the upstream side of the throttle valve 4, such as a carburetor, the throttle valve 4 is slightly I was trying to keep it open. This is to improve the flow of fuel, which is a viscous fluid, and to prevent deterioration in idling performance and starting performance.

<Problems to be solved by the invention> However, according to the throttle valve 4 having the above configuration, since the throttle valve 4 rotates around the downstream surface, for example, if the throttle valve 4 is rotated by an angle θ from a fully closed state, In this case, the circumferential edge 3b of the valve body 3 that forms the gap T ₂ on the upstream side with the inner circumferential wall of the intake passage 1 is the downstream surface, so even though it rotates by the same angle θ as the valve opening degree, On the other hand, the circumferential edge 3c of the valve body 3 forming the downstream gap _T1 is the upstream side surface, and due to the plate thickness t of the valve body 3, it rotates only by an angle β which is smaller than the angle θ. gap
The gap T ₂ is larger than T ₁ .

For this reason, when the throttle valve 4 is adapted to an internal combustion engine such as an SPI system in which fuel is supplied from the upstream side of the throttle valve 4, idling performance and starting performance are impaired. In other words, a large amount of fuel flows downstream guided by the upstream end face of the valve body 3 of the throttle valve 4, so even if the passage area (total of gaps) is the same, if the downstream gap _T1 is small, the fuel flow will be reduced. As a result, idling performance and starting performance deteriorate.

The rotation angle β becomes smaller as the plate thickness t of the valve body 3 becomes thicker for the same throttle valve opening θ, and the larger the diameter of the valve body 3 is, the smaller the gap T ₁ and the gap T ₂ become. The gap between the two countries will widen. Therefore,
The trend of increasing the diameter of the intake passage (throttle chamber) due to the increase in intake passage size due to the increase in output in recent years,
On the other hand, there was an aspect that the idling performance and starting performance were sacrificed.

The present invention was developed in view of the above-mentioned problems, and provides a butterfly-type throttle valve installed in an intake passage in which the flow direction of intake air is set downward approximately along the direction of gravity, when the throttle valve is in an open state. The purpose is to improve the flow of fuel in an internal combustion engine where fuel is supplied from the upstream side of the throttle valve, such as in the SPI system, by making the gap on the downstream side larger than the gap on the upstream side.

<Means for Solving the Problems> Therefore, the present invention provides a throttle valve installed in an intake passage of an internal combustion engine in which the flow direction of intake air is set downward substantially along the direction of gravity, A flat disk-shaped valve body for controlling the opening gap of the throttle valve is rotatably supported with the diametrical direction of the air passage as a rotation axis, and fuel is supplied from the upstream side of the throttle valve. In the butterfly-type throttle valve for an engine, the rotating shaft is provided upstream of the intake passage from the center of the plate thickness of the valve body of the throttle valve.

<Operation> According to this configuration, the angle of the circumferential edge of the valve body with respect to a plane (hereinafter referred to as a reference plane) parallel to both end surfaces of the flat disc-shaped valve body that includes the rotation axis has the following relationship. Become.

In other words, since the distance from the reference plane to the downstream end face of the valve body is greater than the distance from the reference plane to the upstream end face of the valve body, the distance between the upstream peripheral edge of the valve body and the reference plane, which constitutes the gap created on the downstream side, is greater than the distance from the reference plane to the upstream end face of the valve body. The angle between the reference plane and the peripheral edge of the downstream side of the valve body forming the gap formed on the upstream side is larger than the angle between the reference plane and the downstream peripheral edge of the valve body that forms the gap formed on the upstream side. Note that these angles are all angles from the reference plane toward the throttle valve closing direction.

Here, when the throttle valve is rotated from the fully closed state to the opening direction, the larger the angle from the reference plane in the closing direction, the smaller the rotation angle. The circumferential edge portion rotates more than the downstream circumferential edge portion forming the gap formed on the upstream side, and the gap on the downstream side is larger than the gap on the upstream side.

<Example> An example of the present invention will be described below based on FIG. 1.

The butterfly-type throttle valve 10 has a rotation axis C that is a predetermined diameter direction in a cylindrical intake passage 11 in which the flow direction of intake air is set downward substantially along the direction of gravity, and a flat disc-shaped valve body 12. The rotation shaft C is provided on the upstream end face of the intake passage 11 and is rotatably supported, and fuel is injected and supplied from the upstream side of the butterfly throttle valve 10.

Setting of such a rotation axis C is performed, for example, as follows.

That is, the outer peripheral surface of the cylindrical shaft member 13 to which the valve body 12 is fixed is aligned parallel to the axis and further from the axis.
Make a recess by the plate thickness t of 2. Then, such a recess 1
3a, the valve body 12 is fixed to the recess 13.
a and an axial plane parallel to the bottom wall. Throttle valve 10 consisting of shaft member 13 and valve body 12 formed in this way
When the intake passage 11 is rotatably supported with the predetermined diameter direction and the axis of the shaft member 13 aligned so that the recessed portion 13a faces upstream of the intake passage 11, the valve body 12 is positioned upstream of the intake passage 11. The throttle valve 10 can be configured with a rotation axis C on the side end surface.

Note that the throttle valve 10 shown in the figure is connected to the intake passage 1.
The valve body 12 is formed so as to be in a fully closed state at a predetermined angle α inclined with respect to a plane perpendicular to the axis of the valve body 1. In such a fully closed state, the circumferential end surface 1 of the valve body 12
2a is parallel to the inner circumferential wall of the intake passage 11, the predetermined angle α
It is formed at an angle. Throttle valve 1 like this
0, the fully closed state is set at an angle tilted by the predetermined angle α as described above, so the direction of rotation (opening direction) is naturally limited to the direction in which the tilt increases from the fully closed state.

When the throttle valve 10 is rotated in the opening direction from the fully closed state, a gap is created between the valve body 12 and the inner circumferential wall of the intake passage 11, increasing the passage area of the intake passage 11. The gap T ₁ on the downstream side becomes larger than the gap T ₂ that occurs. This is because the rotation axis C is provided on the upstream end face of the valve body 12, so the peripheral edge 12c on the upstream side of the valve body 12, which constitutes the downstream gap _T1 , rotates by the same amount as the throttle opening. On the other hand, the peripheral end 12b on the downstream side of the valve body 12 forming the upstream gap T ₂ is at an angle γ (the larger the plate thickness t of the valve body 12 is, the larger the angle is) with respect to the upstream end surface of the valve body 12. Since the throttle valve is located in the closing direction, the throttle valve rotates only by an angle β obtained by subtracting this angle γ from the throttle valve opening θ. Therefore, T ₁ is larger than T ₂ , which means that the rotation axis C is located upstream of the center of the plate thickness of the flat disc-shaped valve body 12.
In this embodiment, the rotation axis C is provided on the upstream end face of the valve body 12, but the rotation axis C is not limited to this, and any rotation axis C that satisfies the above conditions can be used. Good.

In this way, by making the downstream clearance T ₁ larger than the upstream clearance T ₂ , it is possible to improve the fuel flow in the region where the opening degree is small, and when it is adapted to the SPI system, it improves idle drivability. Startability can be improved.

In the SPI system, a fuel injection valve is provided in the intake passage 11 on the upstream side of the throttle valve 10, and a mixture of fuel and air is injected and supplied into the intake passage 11 from the fuel injection valve through the throttle valve 10. It is designed to be supplied to the engine's fuel chamber. For this reason, it was necessary to keep the throttle valve 10 slightly open even during idling to improve the flow of fuel. Since the gap T ₁ on the downstream side is larger than the gap T ₂ , the flow of fuel guided by the upstream side surface of the intake passage 11 of the valve body 12 and flowing into the gap T ₁ on the downstream side is improved. In other words, since fuel tends to concentrate in the downstream gap _T1 , even if the total gap generated when the throttle valve 10 is opened is the same, the downstream gap
By increasing T ₁ , the fuel flow can be improved. There is also an effect that the fuel that adheres to the upstream end face of the valve body 12 and flows along the surface of the valve body 12 toward the downstream gap T ₁ is atomized well in the gap T ₁ .

Therefore, the throttle valve 10 shown in this embodiment can improve the idling performance and starting performance in the SPI system.

<Effects of the invention> As explained above, according to the invention, the rotation axis of the flat disk-shaped valve body is set upstream of the center of the plate thickness of the valve body, thereby making it possible to open the throttle valve. In this state, the gap on the downstream side can be made larger than the gap on the upstream side.

Therefore, the flow of fuel is improved, and in an internal combustion engine such as an SPI system where fuel is supplied from the upstream side of the throttle valve, the idling performance and starting performance can be improved.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an intake passage showing an embodiment of the present invention, and FIG. 2 is a sectional view of a conventional example. 10...Throttle valve, 11...Intake passage, 1
2... Valve body, 13... Shaft member, C... Rotating shaft.

Claims (1)

[Claims for Utility Model Registration] A throttle valve installed in an intake passage of an internal combustion engine in which the flow direction of intake air is set downward substantially along the direction of gravity, the flat valve controlling the opening gap of the intake passage. In a butterfly type throttle valve for an internal combustion engine, a disc-shaped valve body is rotatably supported with the diametrical direction of the intake passage as an axis of rotation, and fuel is supplied from the upstream side of the throttle valve. . A butterfly-type throttle valve for an internal combustion engine, characterized in that the rotating shaft is provided upstream in an intake passage from the center of plate thickness of a valve body of the throttle valve.