JP2002201968A - Air intake device for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of part items, by making a throttle valve in concurrent use for a function of an air intake control valve. SOLUTION: A throttle valve 14 is arranged just in the upstream of a pair of intake air ports 6a, 6b, a throttle shaft 15 supporting the throttle valve 14 is arranged in a crossing direction relating to an axial line Lp connecting intake valves 8 arranged in both the intake air ports 6a, 6b. When the throttle valve 14 is small opened, suction air is guided to a side of a lower valve part 14a along a slope of a surface of the throttle valve 14, suction air accelerating a flow speed flows from an opening part in a side of the lower valve part 14a to a side of a suction port 6a opened to a side of the lower valve part 14a, and strong swirl flow is generated in a combustion chamber 5. When an opening of the throttle valve 14 is increased, by allowing the suction air to flow from both the lower valve part 14a and an upper valve part 14b, generation of the swirl flow is suppressed while decreasing air intake resistance, a suction air amount flowing in the combustion chamber 5 is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake system for an engine in which a throttle valve is disposed immediately upstream of an intake port, and the throttle valve also functions as an intake control valve.

[0002]

2. Description of the Related Art Conventionally, in a four-stroke engine, in a low / medium load operation region including a small amount of intake air and an idle operation, a swirl flow such as an axial swirl flow and a tumble flow such as an axial swirl flow. Is known to improve combustion efficiency and, in a high load operation region where the amount of intake air is large, to improve the charging efficiency by reducing intake resistance.

For example, in Japanese Patent Application Laid-Open No. 9-280066, a notch is formed in an intake control valve in an engine that supplies intake air to a single cylinder from a pair of intake ports. There is disclosed a technique of generating a swirl flow in a combustion chamber by closing an intake control valve and allowing most of the intake air to flow through a notch.

[0004]

However, according to the technique disclosed in the above publication, both an intake control valve for controlling the intake air flow and a throttle valve for controlling the intake air flow are provided in the intake passage. In addition to the increase in the number of parts, there is a problem that the distance between each cylinder and the throttle valve is long, so that the throttle response is deteriorated.

[0005] Further, since the intake control valves are provided in the intake manifold, it is necessary to provide the intake control valves individually for each cylinder and to link the intake control valves. In this case, if each valve shaft is to be connected via a link mechanism, the link mechanism protrudes outside the intake manifold, and the shape becomes large, and interference with other parts is likely to occur. There's a problem.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances and provides an intake device for an engine capable of not only obtaining a good throttle response with a simple structure but also realizing a compact size. Aim.

[0007]

In order to achieve the above object, an intake device for an engine according to the present invention has a throttle bore disposed immediately upstream of a pair of intake ports formed in a cylinder head, and a throttle valve is provided in the throttle bore. And a throttle shaft supporting the throttle valve is disposed in a direction intersecting an axis connecting the centers of the intake valves disposed in the pair of intake ports.

In such a configuration, when the throttle valve is slightly opened, most of the intake air is guided along the surface of the throttle valve inclined downward, and the opening between the lower side of the throttle valve and the throttle bore is opened. It flows into the one of the pair of intake ports at high speed from the portion, and generates a vortex in the combustion chamber. And
When the opening degree of the throttle valve is gradually increased, the intake resistance is gradually reduced, the generation of the vortex is suppressed, and the amount of intake air flowing into the combustion chamber is increased.

In this case, it is preferable that: 1) a set opening from the fully closed state of the throttle valve to the throttle bore opposed to the edge of one half of the throttle valve which rotates about the throttle shaft; Characterized in that a concave curved surface portion for maintaining the valve-closed state in the range is provided.

2) The throttle bores are arranged in two rows with a gap therebetween, the throttle shafts provided in the respective throttle bores are arranged in parallel, and the respective throttle shafts are projected toward the gaps. Shafts of the throttle shafts protruding toward the gaps are connected to each other via a link mechanism.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic diagram of an intake device for an engine. Reference numeral 1 in the figure denotes an engine body, which in the present embodiment indicates a single bank of a four-cylinder V-type or horizontally opposed engine.

As shown in FIGS. 3 to 5, each cylinder has a cylinder block 2 and a cylinder head 3 of an engine body 1.
The combustion chamber 5 is formed by the piston 4 and the combustion chamber 5.

The cylinder head 3 is formed with bifurcated intake ports 6a and 6b and an exhaust port 7 which communicate with the combustion chamber 5. Each intake port 6a, 6b is formed symmetrically via a partition 6c. Each of the intake ports 6a and 6b is formed in a shape capable of generating a swirl flow with respect to intake air flowing into the combustion chamber 5 at a high speed by a straight portion on the upstream side and a curved portion on the downstream side. . Further, an intake valve 8 is provided at an outlet of each of the intake ports 6a and 6b.

Also, as shown in FIG.
A throttle body 9 is fixedly mounted on an outer surface of the throttle body 9, an air chamber 12 is connected to the throttle body 9 via an intake manifold 11, and an upstream of the air chamber 12 is connected to an air cleaner (not shown) through an intake passage 13. )).

The throttle body 9 is formed with two throttle bores 10, 10 corresponding to each cylinder.
Each of the throttle bores 10 communicates with a collecting portion of a pair of intake ports 6a and 6b provided for each cylinder.

A throttle valve 14 is disposed in each of the throttle bores 10, 10, and substantially the center of the throttle valve 14 is fixed to a throttle shaft 15, and the throttle shaft 15 is rotatable with respect to the throttle body 9. Supported.

As shown in FIG. 6, when the ignition switch is turned off, the throttle valve 14 is in a fully closed state. When the ignition switch is turned on, the throttle valve 14 is set so as to open slightly in the clockwise direction in FIG. I have. In the following description, a half that opens downward of the throttle valve 14 is referred to as a lower valve portion 14a, and a half that opens upward is referred to as an upper valve portion 14b.

In FIG. 7, if the axis connecting the centers of the intake valves 8 disposed in the intake ports 6a and 6b is Lp (see FIG. 5), this axis Lp is moved upstream along the intake flow. The positional relationship between the intake valves 8, 8 and the throttle shaft 15 when moved in parallel is shown. As shown in FIG.
Reference numeral 5 is disposed parallel to the axis Lp from the front to the rear of the drawing and crosses at an intersection angle θ1. The intersection angle θ1 may be in the range of 0 ° <θ1 <90 °, but is set to 45 ° in the present embodiment.

By setting the intersection angle θ1 to 45 °,
The lower valve portion 14a can be disposed on the intake port 6a, while the upper valve portion 14b can be disposed so as to largely overlap the intake port 6b.
It can protrude in the direction of the gap 9a between the throttle bores 10, 10.

The throttle valve 14 constitutes a so-called electronically controlled throttle (ETC) for electronically controlling the valve opening.
A shaft end protruding in the direction of the gap 9a between the 10 is continuously provided via a link mechanism 16 by gear meshing, and a throttle actuator 17 such as a motor is connected to the link mechanism 16 continuously. This throttle actuator 17
It is driven in accordance with a control signal corresponding to a throttle opening instruction value output from an electronic control unit (ECU) not shown.

In this manner, as shown in FIG. 2, the shaft ends of the throttle shafts 15, 15 project in the direction of the gap 9a between the throttle bores 10, 10, and both shaft ends are connected to the link mechanism 1.
6, the structure of the link mechanism 16 can be simplified. Further, the link mechanism 16 is connected to the gap 9.
a, the link mechanism 16 does not protrude outside the throttle body 9 so that the shape can be made compact. Interference is avoided, and the degree of freedom in outfitting is increased.

The throttle bore 10 opposing the upper valve portion 14b extends along the locus of the outer periphery of the upper valve portion 14b in a region of a set opening θ2 in which the upper valve portion 14b is in a range from fully closed to medium load operation. A concave curved surface portion 10a having a curved shape is formed.

Therefore, until the outer periphery of the upper valve portion 14b passes through the concave curved surface portion 10a, that is, until the opening of the throttle valve 14 becomes equal to or more than the set opening θ2, the upper valve portion 14b
Is maintained, and the intake air flows only from the lower valve portion 14a side. The intake air flowing from the lower valve portion 14a flows into the combustion chamber 5 along the inner wall of the one intake port 6a, and generates a swirl flow in the combustion chamber 5.

Next, the operation of the intake device having such a configuration will be described. In the low load operation region including the idling operation, the throttle valve 14 constituting the electronically controlled throttle (ETC) is slightly rotated clockwise in FIG.
The lower valve portion 14a is opened, while the upper valve portion 14b is kept closed because the outer periphery of the upper valve portion 14b only rotates along the concave curved surface portion 10a formed in the throttle bore 10. Have been.

As a result, as shown in FIG. 3, only the lower valve portion 14a of the throttle valve 14 is opened, and the intake air flows along the slope of the lower valve portion 14 along the inclination of the surface of the throttle valve 14.
It is intensively guided to the side a, and flows at an increased flow velocity in a downstream direction from an opening formed between the lower valve portion 14a and the throttle bore 10 provided on the outer periphery thereof.

Most of the intake air whose flow velocity has been increased flows to the intake port 6a provided at a position corresponding to the lower valve portion 14a, and the combustion chamber 5 extends along the wall surface of the intake port 6a. And generates a swirl flow that is swirling in the axial direction in the combustion chamber 5.

As described above, in the low load operation region, most of the intake air passes through the lower valve portion 14a, and the one intake port 6
Since it flows to the a side, a strong swirl flow can be generated in the combustion chamber 5.

In a medium load operation region in which the accelerator pedal (not shown) is lightly depressed, the throttle actuator 17 is driven in accordance with the depression amount of the accelerator pedal.
The throttle valve 14 is further rotated clockwise in FIG. 6 via the link mechanism 16.

At this time, the outer periphery of the upper valve portion 14b is closed by the concave curved surface portion 10a until the opening of the throttle valve 14 exceeds the set opening θ2.
Only the opening area on the side a increases, so that more intake air is introduced from the lower valve portion 14a to the intake port 6a at a higher flow rate than in the low load operation region, and A strong swirl flow is generated.

As described above, in the low / medium load operation range from when the throttle valve 14 is in the small opening state to the set opening θ2 (see FIG. 6), the strong swirl flow generated in the combustion chamber 5 causes The gas flow is enhanced and good combustion can be obtained.

Then, when the accelerator pedal is further depressed and the opening of the throttle valve 14 reaches a high load operation region exceeding the set opening θ2, the lower valve portion 1 of the throttle valve 14
4a side opening area further increases and the upper valve portion 14
The side b gradually opens, and the intake air flows from both valve portions 14a and 14b to the downstream side of the throttle valve 14.

Then, the intake air is supplied to one of the intake ports 6.
In addition to a, the air also flows into the other intake port 6b opened at a position corresponding to the upper valve portion 14b, and is supplied to the combustion chamber 5 from both the intake ports 6a and 6b.

As described above, in the high load operation range, the intake resistance gradually decreases and the amount of intake air flowing into the combustion chamber 5 increases due to the opening of the two valve portions 14a and 14b of the throttle valve 14.

As described above, in this embodiment, the throttle valve 14 is disposed immediately upstream of the intake ports 6a and 6b,
Since the function of the conventional intake control valve is also used for the throttle valve 14, the number of parts can be reduced and the structure can be simplified. Furthermore, the wall surface of the throttle bore 10 facing the upper valve 14b can be provided. The concave curved surface portion 10a is formed, and in the low / medium load operation region, the closed state of the upper valve portion 14b of the throttle valve 14 is maintained, so that the intake air flows only downstream from the lower valve portion 14a. It can be supplied at high speed to one intake port 6a corresponding to the lower valve portion 14a.
As a result, a strong swirl flow can be generated in the combustion chamber 5.

Further, since the throttle valve 14 is disposed immediately upstream of the intake port 6, the throttle response is improved and the acceleration performance according to the driver's intention can be obtained.

The present invention is not limited to the above-described embodiment. For example, an upstream side and a downstream side of the throttle bore 10 straddling the throttle valve 14 are communicated with each other through an air bypass passage. Number control (IS
C) In an engine having a so-called idle control mechanism with a valve interposed, the throttle valve 14 may be kept fully closed during idling operation.

The throttle valve 14 does not need to constitute an electronically controlled throttle, and may be a general mechanical throttle in which the link mechanism 16 and the accelerator pedal are connected via a throttle wire. Further, a throttle actuator may be connected to each of the throttle valves 14, 14, and the throttle valves 14, 14 may be individually controlled.

Further, in the present embodiment, the intake port 6
Although a and 6b have a port shape for generating a swirl flow,
A port shape that generates a tumble flow may be used.

[0039]

As described above, according to the present invention,
Since the function of the intake control valve also serves as the throttle valve, the number of parts can be reduced. Further, since the throttle valve is disposed immediately upstream of the intake port, the throttle response is improved, and the acceleration performance according to the driver's intention can be obtained.

Further, the throttle shaft supporting the throttle valve is disposed in a direction intersecting with the axis connecting the centers of the intake valves disposed in the pair of intake ports formed in the cylinder head. The link mechanism can be disposed in the throttle body, and a compact shape can be realized.

[Brief description of the drawings]

FIG. 1 is a schematic view of an intake device of an engine.

FIG. 2 is a front view of a throttle body.

FIG. 3 is a sectional view taken along the line III-III of FIG. 2 when the throttle valve is slightly opened.

FIG. 4 is a sectional view corresponding to FIG. 3 when the throttle valve is fully opened.

FIG. 5 is a sectional view taken along line VV of FIG. 2;

FIG. 6 is a sectional view taken along line VI-VI of FIG. 2;

FIG. 7 is an explanatory diagram showing a positional relationship between an intake valve and a throttle shaft.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine main body 6 Intake port 9a Gap 10 Throttle bore 10a Concave curved surface 14 Throttle valve 15 Throttle shaft 16 Link mechanism Lp Axis θ2 Set opening

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Claims (3)

[Claims] A throttle bore is provided immediately upstream of a pair of intake ports formed in a cylinder head, a throttle valve is provided in the throttle bore, and a throttle shaft supporting the throttle valve is provided in the pair of intake ports. An intake device for an engine, wherein the intake device is disposed in a direction crossing an axis connecting the centers of the provided intake valves. 2. A closed state in a range from a fully closed state of the throttle valve to a set opening degree in the throttle bore opposed to an edge of one half of the throttle valve which rotates about the throttle shaft. 2. The intake device for an engine according to claim 1, wherein a concave curved surface portion for maintaining the pressure is provided. 3. The throttle bores are arranged in two rows via a gap, the throttle shafts provided in each of the throttle bores are arranged in parallel, and each of the throttle shafts protrudes toward the gap. 3. The intake system for an engine according to claim 1, wherein shaft portions of each of the throttle shafts protruding toward the gaps are connected via a link mechanism.