JPH10280962A - Intake switching device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the leakage of an intake air at the closing time of a valve by forming a valve seat to the downstream side of an intake flow slantingly and pivoting the one end of the upperstream side of a selector valve, in a device for opening/closing the selector valve provided on the opening part connected to the sub-intake pipe route in a main intake pipe route and varying an intake passage length. SOLUTION: A short sub-intake pipe route 7 whose length from a clean side case 3 is short is connected to the bottom on the way of a main intake pipe route 6 so as to be opened and a valve seat 8 is formed around this opening. This valve seat 8 is slanted by a proper angle θ inward the main intake pipe route 6 heading for the downstream side of an intake flow in the main intake pipe route 6 and in the selector valve 9 sit on this valve seat 8, the one end of the upperstream side for the intake flow is pivoted turnably by a pin shaft 10 for the main intake pipe route 6 and a seal body 11 made of a soft elastic body is provided on the lower surface of the selector valve 9. This selector valve 9 is opened/closed by introducing the intake negative pressure of the more downstream side than a throttle valve to the pressure room 13 by a diaphragm mechanism 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine, in which intake air is introduced through a long intake path in accordance with an operating range of the internal combustion engine, and is introduced through a short intake path. The present invention relates to a device for switching between the two cases.

[0002]

2. Description of the Related Art When introducing intake air to an internal combustion engine via an intake passage, if the length of the intake passage is always the same,
A phenomenon occurs in which the output of the internal combustion engine decreases in a certain operating range. Therefore, in a recent internal combustion engine, the intake path is provided with a portion that lengthens the intake path and a portion that shortens the intake path. By switching between the case of introduction through the intake passage and the case of introduction through the short intake path, the output of the internal combustion engine is prevented from lowering in a certain operating range ( For example,
No. 28530).

In this case, the conventional switching device connects a main intake pipe to the internal combustion engine with a sub intake pipe that lengthens or shortens an intake path to the internal combustion engine. In the part of the opening of the auxiliary intake pipe in the road,
A switching valve is provided by rotatably pivoting the base end thereof, and the switching valve is biased by a spring so as to always close the opening of the sub intake pipe, while the switching valve is connected to the intake path. A pressure actuating mechanism such as a diaphragm mechanism related to the intake negative pressure downstream of the throttle valve in the inside is configured to open and rotate against the spring, and thus has the following problems. .

[0004]

That is, in the prior art, the opening of the sub intake pipe into the main intake pipe is opened and closed by a switching valve provided in the main intake pipe. In the state where intake air to the internal combustion engine is introduced from the main intake line, the leading end of the switching valve has a valve seat surface due to pulsation of intake air flowing in the main intake line. From the main intake line, and a considerable amount of intake air from the sub-intake line leaks into the main intake line, so that the effect of switching the intake path is reduced. was there.

In this case, in order to reduce the leakage and inflow of the intake air from the sub intake pipe to the main intake pipe, the spring force for urging the switching valve so as to close the opening of the sub intake pipe is increased. However, if the spring force on the switching valve is increased, a large force is required when the switching valve is opened and rotated against the spring force, so that the switching sensitivity is reduced. In addition, the pressure operating mechanism such as the diaphragm mechanism must be increased in size.

It is a technical object of the present invention to provide an air intake switching device that solves these problems.

[0007]

SUMMARY OF THE INVENTION In order to attain this technical object, the present invention provides a method of manufacturing a vehicle, comprising the steps of: adding a length of an intake path to an internal combustion engine to a main intake pipe in the middle of the intake path to the internal combustion engine; A sub-intake line which is longer or shorter than when passing through the line is connected, and a valve seat around the opening is provided in an opening portion of the sub-intake line in the main intake line. A switching valve which is biased so as to always contact the surface with a spring, and wherein the switching valve is configured to be opened against the spring by a pressure operating mechanism such as a diaphragm mechanism. In the switching device, one end of the switching valve on the upstream side with respect to the intake air flow in the main intake line is pivotally connected to the inside of the main intake line while being rotatably connected to the sub intake line. The valve seat surface around the opening into the main intake line is Toward the downstream side of Les inclined by appropriate angle inwardly of the main intake pipe. It was constituted say ".

[0008]

With such a construction, the end of the switching valve opposite to the pivot portion at one end thereof is located ahead of the one end when the switching valve is closed and rotated by the spring force. , The distal end portion is pressed against the valve seat surface with a stronger spring force than the one end portion.

[0009] In addition to the above, the valve seat surface is inclined as described above, so that the switching valve contacting the valve seat surface has:
The dynamic pressure of the intake air flowing in the main intake pipe acts to further press the switching valve against the valve seat surface. The lifting of the portion from the valve seat surface can be reliably suppressed without increasing the spring force.

Therefore, according to the present invention, when the intake air to the internal combustion engine is introduced through the main intake line, the intake air from the auxiliary intake line leaks into the main intake line. Can be greatly reduced, and the switching sensitivity can be improved, so that the output of the internal combustion engine can be reliably improved by switching the intake air without increasing the size of the pressure operating mechanism such as the diaphragm mechanism for the switching valve. Has an effect.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In this figure, reference numeral 1 denotes an air cleaner for an internal combustion engine. The air cleaner 1 is configured by sandwiching a filter element 4 between a dust side case 2 and a clean side case 3. Is connected to an intake pipe 5 for atmospheric air, and the clean side case 3 has a throttle body or a carburetor (both not shown) connected to an intake manifold in the internal combustion engine.
A relatively long length of main intake line 6 is connected.

In the middle of the main intake line 6, a sub intake line 7 having a short length from the clean side case 3 is connected so as to open to the bottom of the main intake line 6. A valve seat surface 8 is formed in the pipe 6 around the opening of the sub intake pipe 7, and the valve seat 8 is located downstream of the intake flow indicated by an arrow in the main intake pipe 6. The main intake pipe 6 is inclined inward toward the side by an appropriate angle θ.

Reference numeral 9 denotes a plate-like switching valve provided in the main intake pipe 6, one end of the switching valve 9 being upstream of the intake flow indicated by an arrow in the main intake pipe. The portion is pivotally connected to the inside of the main intake pipe line 6 by a pin shaft 10, and a seal body 11 made of a soft elastic material such as rubber is provided on a lower surface of the switching valve 9. ing. And
Reference numeral 12 denotes a diaphragm mechanism for opening and closing the switching valve 9. The diaphragm mechanism 12 includes a diaphragm 14 that forms a pressure chamber 13, and a rod 15 that connects the switching valve 9 to the diaphragm 14. A spring 16 for urging the switching valve 9 against the valve seat surface 8, and introducing an intake negative pressure downstream of a throttle valve (not shown) into the pressure chamber 13, whereby the intake air is reduced. When the negative pressure increases, the switching valve 9 is configured to open in a direction away from the valve seat surface 8 against its spring 16.

In this configuration, in the operating range where the intake negative pressure downstream of the throttle valve is small, the switching valve 9
The spring 16 of the diaphragm mechanism 12
, All the intake air to the internal combustion engine is introduced via the main intake pipe 6.
When the intake negative pressure becomes a large operating range, the switching valve 9
However, as shown by a two-dot chain line in the figure, the diaphragm mechanism 12 opens and rotates away from the valve seat surface 8 against the spring 16, so that the intake air to the internal combustion engine has a long length. The path introduced via the main intake line 6 is switched to a path introduced via the sub intake line 7 having a short length.

In this case, the valve seat surface 8 is inclined at an appropriate angle θ inward of the main intake line 6 toward the downstream side of the intake flow indicated by an arrow in the main intake line 6. One end of the switching valve 9 on the upstream side with respect to the intake air flow indicated by an arrow in the main intake pipe 6 is pivotally connected to the inside of the main intake pipe 6 by a pin shaft 10. Thus, the tip of the switching valve 9 opposite to the pivotal connection at one end thereof contacts the valve seat surface 8 before the one end when the switching valve 9 is closed and rotated by the spring 16. Therefore, this tip is pressed against the valve seat surface 8 with a stronger spring force than the one end.

In addition to this, the switching valve 9 which comes into contact with the valve seat surface 8 by tilting the valve seat surface 8 as described above.
In this case, the dynamic pressure of the intake air flowing in the main intake pipe 6 acts so as to further press the switching valve 9 against the valve seat surface 8, and this is combined with the above. And the switching valve 9
The lifting of the distal end from the valve seat surface 8 can be reliably suppressed without increasing the spring force of the spring 16.

In the above-described embodiment of the present invention, the case where this is incorporated in an air cleaner is shown. However, the present invention is not limited to this,
It goes without saying that the present invention may be applied to a portion from the air cleaner to the internal combustion engine or a portion from the intake portion of the atmospheric air to the air cleaner.

[Brief description of the drawings]

FIG. 1 is a front view of an air cleaner to which an embodiment of the present invention is applied.

FIG. 2 is an enlarged sectional view of a main part of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Air cleaner 4 Filter element 5 Atmospheric air intake pipe 6 Main intake pipe 7 Sub intake pipe 8 Valve seat surface 9 Switching valve 10 Pin shaft 12 Diaphragm mechanism 16 Spring

Claims (1)

[Claims] 1. A sub-intake pipe in which a length of an intake path to an internal combustion engine is made longer or shorter than a case of passing through the main intake pipe in a main intake pipe in the middle of an intake path to the internal combustion engine. The main intake passage is biased so as to always contact the valve seat surface around the opening in the main intake passage with a spring. An intake switching device comprising a switching valve, wherein the switching valve is configured to open against the spring by a pressure operating mechanism such as a diaphragm mechanism. The one end on the upstream side is rotatably pivoted with respect to the main intake pipe, while the valve seat surface around the opening of the sub intake pipe into the main intake pipe is A suitable angle inward of the main intake line toward the downstream side of the intake flow in the main intake line An intake switching device for an internal combustion engine, characterized in that it is inclined.