JPH0430371Y2 - - Google Patents

Description

[Detailed description of the invention] A. Purpose of the invention (1) Industrial application field The present invention is an intake noise damping device for an internal combustion engine, in particular, a resonance box that communicates with the intake passage of an internal combustion engine through a cylindrical communication pipe. Concerning the improvement of what is being done.

(2) Conventional technology Conventionally, in this type of intake sound attenuation device, in order to attenuate specific intake sounds with different frequencies, a resonance box is connected to the intake pipe through two parallel communicating pipes having large and small cross-sectional areas. It is known that the effective opening area of the communicating pipe can be adjusted in two stages, large and small, by connecting both communicating pipes to the pipe and opening and closing them alternately using a valve mechanism. ).

(3) Problems that the invention aims to solve Conventional intake noise damping devices require two communicating pipes, and they must be opened and closed alternately by a valve mechanism, so the overall structure is not complicated. I can't escape it.

The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a simple and effective intake noise attenuation device that can accurately attenuate specific intake sounds having different frequencies.

B. Structure of the device (1) Means for solving the problem In order to achieve the above object, the present invention divides the inside of the communicating pipe into a large passage with a large cross-sectional area and a small passage with a small cross-sectional area. The partition wall is curved into a mountain shape with the top protruding toward the main passageway and terminating before the center of the communication pipe, and rotates around the diameter line of the communication pipe adjacent to the top of the partition wall to open the main passageway. It is characterized by a butterfly-type on-off valve that opens and closes and is pivotally supported on the communication pipe.

(2) Effect When the on-off valve is closed, the resonance box communicates with the intake passage only through the small passage of the communication pipe, so it is possible to attenuate the low frequency intake noise generated in the intake passage. When opened, the resonance box communicates with the intake passage through both the large and small passages of the communication pipe, so that high-frequency intake noise generated in the intake passage can be attenuated.

Moreover, since the small passage is defined by a part of the inner surface of the cylindrical communicating tube and the concave surface of the partition wall curved in a chevron shape, its cross-sectional shape is close to a circle, and therefore the cross-sectional area of the small passage is Despite its small size, its surface area is also relatively small, so when closing the on-off valve, even if you ignore the resistance determined by the surface area of the small passage,
It is possible to attenuate specific low-frequency intake sounds as calculated.

In addition, the convex surface of the chevron-shaped bulkhead can cooperate with the inner surface of the communication pipe facing the large passageway to provide an alignment effect to the closing valve, thereby smoothing the opening and closing operation of the valve. At the same time, uneven wear can be prevented.

(3) Embodiment An embodiment of the present invention will be described below with reference to the drawings. First, in FIG. 1, a throttle body 3 and an air cleaner 4 are installed in an intake passage 2 of an automobile multi-cylinder internal combustion engine 1 in order from the downstream side. Furthermore, a resonator 5 is connected to the section between the air cleaner 4 and the inlet 2a of the intake passage 2.

In Figures 1 to 6, the resonator 5
The main elements are a resonance box 6 and a communication pipe 7 that communicates the resonance box 6 with the intake passage 2, both of which are made of synthetic resin.

The communication tube 7 has a cylindrical shape, and its interior is divided by a partition wall 8 into a large passage 7a with a large cross-sectional area and a small passage 7b with a small cross-sectional area. The partition wall 8 is formed integrally with the communication pipe 7 and is curved in a mountain shape with the top facing the large passage 7a side, and the top ends before the center of the communication pipe 7.

The communication pipe 7 is provided with an on-off valve 9 for opening and closing the large passage 7a. This on-off valve 9 is made of synthetic resin and is located adjacent to the top of the partition wall 8 with a communicating pipe 7.
A valve shaft 10 disposed on the diameter line of
The valve plate 11 is integrally formed on one side of the middle part of the valve plate 10, and is configured in a butterfly shape.

In order to regulate the closed position of the on-off valve 9, rib-shaped stoppers 12 and 13 capable of supporting the peripheral edge of the valve plate 11 are provided on the inner wall of the communicating pipe 7 facing the large passage 7a and on the convex wall of the partition wall 8. It is installed protrudingly.

One end of the valve shaft 10 of the on-off valve 9 is supported in a bearing hole 14 bored in one side wall of the communication pipe 7, and the other end is fitted into the other side wall of the communication pipe 7 and a notch 15 provided therein. A lever 18 is integrally formed at the tip of the other end.

The notch 15 opens at the inner end of the communication tube 7, that is, the opening end on the side of the resonance box 6, and the retainer is inserted into the notch 15.
The retainer 16 is fitted from the outside of the communication pipe 7, and in order to maintain the fitted state, protrusions 19 are elastically engaged with each other on opposing surfaces extending in the longitudinal direction of the retainer 16 and the notch 15. and grooves 20 are provided, respectively. In addition, the retainer 1 in the axial direction of the communication pipe 7
In order to prevent the retainer 16 and the notch 15 from being pulled out, the retainer 16 and the notch 15 are provided with a small protrusion 21 and a small notch 2 that extend in the circumferential direction of the communicating tube 7 and engage with each other.
2 are provided respectively.

An annular protrusion 23 is formed on the outer circumferential surface of the communication tube 7, passing through the axial center thereof, and with this annular protrusion 23 as a boundary, the inner half of the communication tube 7 is connected to the connecting tube 6a of the resonance box 6. The outer end half is inserted into the connecting pipe 2a of the intake passage 2. The communication pipe 7 and the connection pipe 6 are provided to prevent the communication pipe 7 from coming out from the connection pipe 6a.
A locking pawl 24 and a locking hole 25 that elastically engage with each other are provided on the opposing surface of a.

When the communicating tube 7 is fitted into and held in the connecting tube 6a in this way, the retainer 16 is reliably prevented from detaching from the notch 15 by the connecting tube 6a.

A diaphragm 28 of a negative pressure actuator 27 is connected to the lever 18 of the on-off valve 9 via a connecting rod 26. A housing 29 of the negative pressure actuator 27 is fixed to the resonance box 6, and its interior is divided into an atmospheric chamber 30 and a negative pressure chamber 31 by a diaphragm 28. A return spring 32 that biases in the valve opening direction is housed.

The negative pressure chamber 31 is selectively communicated with a boost negative pressure outlet 34 of the intake passage 2 and an atmospheric air introduction filter 35 by an electromagnetic switching valve 33 .

That is, the electromagnetic switching valve 33 has a first port 37 connected to the negative pressure chamber 31 , a second port 38 connected to the boost negative pressure extraction hole 34 , and a third port 39 connected to the atmospheric air introduction filter 35 in its valve case 36 .
has. The valve case 36 also includes a valve body 40 that alternately opens and closes the second port 38 and the third port 39, a valve spring 41 that biases the valve body 40 in the closing direction of the second port 38, and a valve body when energized. A solenoid 42 is provided to operate the solenoid 40 in the direction of closing the third port 39. Therefore, when the valve body 40 closes the second port 38, the first port 37 and the third port 3
When the valve body 40 closes the third port 39, the first port 37 and the second port 38 communicate with each other.

The energizing circuit 44 that connects the solenoid 42 to the battery 43 includes a main switch 45 that is linked to an ignition switch (not shown) of the engine 1, and a normally closed high-speed operating state that opens when a predetermined high-speed operating state of the engine 1 is detected. A detection switch 46 is inserted in series.

The air introduction filter 35 is disposed within the resonance box 61 and is attached to an air pipe 47 made of hard synthetic resin that is directed to the partition wall 8 of the communication pipe 7.
This air pipe 47 is connected via a rubber tube 48 to a connecting pipe connected to the third port 39 of the valve case 36 . In this way, the air introduction filter 35 is always in communication with the third port 39.

In order to support the air pipe 47, a pair of clip pieces 49, 49 for elastically holding the air pipe 47 are provided on the inner wall of the partition wall 8 on the side of the small passage 7b.

In the figure, reference numeral 50 denotes a dust removal screen stretched over the outer end of the communication pipe 7, that is, the open end on the side of the intake passage 2.

Next, to explain the operation of this embodiment, the engine 1
In the stopped state, the main switch 45 is open, so the solenoid 42 is switched to the demagnetized electromagnetic switching valve 33.
As a result, the negative pressure chamber 31 of the negative pressure actuator 27 is communicated with the atmospheric air introduction filter 35 . Therefore, the negative pressure actuator 27 is in an inoperative state, and the resilient force of the return spring 32 holds the on-off valve 9 of the communication pipe 7 in the open position as shown by the solid line.

Now, when the ignition switch (not shown) is closed to operate the engine 1, the main switch 45 is
Since the solenoid 42 is energized by electricity from the battery 43, the electromagnetic switching valve 33
The negative pressure chamber 31 of the negative pressure actuator 27 is communicated with the boost negative pressure extraction hole 34 . Then, negative pressure actuator 2
7 is activated by introducing boost negative pressure generated by the operation of the engine 1 into the negative pressure chamber 31, and returns the diaphragm 28 to the negative pressure chamber 31 side against the force of the spring 32 by the suction action of the introduced negative pressure. Then, the connecting rod 26 is pulled to close the on-off valve 9 as shown by the chain line in FIG.

In this way, the large passage 7a of the communication pipe 7 is closed by the on-off valve 9, so the resonance box 6 communicates with the intake passage 2 only through the small passage 7b, and this state continues during low-speed operation of the engine 1. do.

Next, when the engine 1 shifts to a predetermined high-speed operating state, the high-speed operating state detection switch 46 opens, so the solenoid 42 of the electromagnetic switching valve 33 is demagnetized again. Therefore, the negative pressure actuator 27 introduces the air filtered by the air introduction filter 35 into the negative pressure chamber 31, becomes inactive, and opens the on-off valve 9 again by the elastic force of the return spring 32. .

When the large passage 7a of the communication pipe 7 is thus opened, the resonance box 6 communicates with the intake passage 2 via both the large and small passages 7a and 7b.

Incidentally, during operation of the engine 1, intake noise generated in the intake passage 2 is attenuated by the resonator 5, and the frequency of the attenuated intake noise can be expressed by the following equation.

However, f: Frequency of intake sound to be attenuated C: Sound velocity V: Volume of resonance box 6: Length of communication pipe 7 S: Opening area of communication pipe 7 K: Resistance determined by effective passage surface area of communication pipe Top In the formula, the opening area S of the communication pipe 7 corresponds to the cross-sectional area of the small passage 7b when the engine 1 is operated at low speed, and corresponds to the total cross-sectional area of both the large and small passages 7a and 7b when the engine 1 is operated at high speed. In this way, by changing the opening area of the communication pipe 7 depending on the operating state of the engine 1, intake noise having a specific frequency can be attenuated in each operating state.

During low-speed operation of the engine 1 with the on-off valve 9 closed,
When the ignition switch is opened to stop the engine 1, the main switch 45 is also opened, so atmospheric air is introduced into the negative pressure chamber 31 of the negative pressure actuator 27, and the on-off valve 9 is opened by the elastic force of the return spring 32. be done.

In this way, the on-off valve 9 is closed every time the operation of the engine 1 is started and opened every time the operation is finished, so even if the engine 1 does not move out of the low speed range during operation, it can be opened and closed. Valve 9 will not remain closed for long periods of time. Therefore, the on-off valve 9 due to deposits such as dust
can prevent stalemate.

During operation of the engine 1, in the communication pipe 7 of the resonator 5, there is only vibration of the air column, but no air enters or exits.Moreover, since a dust removal screen 50 is provided at the outer end of the communication pipe 7, resonance occurs. The inside of the box 6 is kept relatively clean at all times with very little foreign matter entering. An air introduction filter 35 for introducing air into the negative pressure chamber 31 of the negative pressure actuator 27 is disposed in such a resonance box 6.
No. 5 does not cause clogging for a long period of time and can exhibit normal filtration function.

Further, since the small passage 7b having a predetermined small cross-sectional area is defined in the communication pipe 7 by the partition wall 8 curved in a chevron shape, the surface area is smaller than that in the case where the partition wall 8 is made into a flat plate shape. Therefore, when the engine 1 is operating at low speed, even if K in the above equation is ignored, intake noise at a specific frequency can be attenuated approximately as calculated.

Moreover, when the on-off valve 9 is closed, the chevron-shaped partition wall 8
This provides an alignment effect to the on-off valve 9 together with the inner wall of the communication pipe 7 facing the large passage 7a, so that the opening/closing operation of the on-off valve 9 can be made smooth and uneven wear on the on-off valve 9 can be prevented.

Further, the valve shaft 10 of the on-off valve 9 has one end supported in a bearing hole 14 of the communication pipe 7 and the other end supported by the communication pipe 7.
The retainer 16 is supported in a bearing hole 17 defined between the retainer 16 and the retainer 16 in the notch 15 of the communication pipe 7.
However, since the connecting pipe 6a of the resonance box 6 that fits and locks the communication pipe 7 prevents it from coming off, the retainer 1 does not need to be fitted with any special means to prevent it from coming off.
6 can be fixed in a fixed position, and the support of the valve stem 10 can be ensured.

C. Effects of the invention As described above, according to the invention, the communicating pipe is provided with a partition wall that divides the inside into a small passage and a large passage,
Since the main passage was opened and closed by an on-off valve,
A very simple structure with one communication pipe and one on-off valve can attenuate specific intake sounds with different frequencies.

Moreover, since the partition wall is curved in a mountain shape with the top protruding toward the large passageway and terminating in front of the center of the communicating pipe, the surface area of the small passageway can be made as small as possible, and the resistance caused by the surface area can be ignored. This makes it possible to accurately attenuate specific low-frequency intake noise as calculated when the on-off valve closes.

Moreover, since the opening/closing valve is configured in a butterfly type that rotates around the diameter line of the communicating pipe adjacent to the top of the chevron-shaped bulkhead, it can be opened and closed by the convex surface of the chevron-shaped bulkhead and the inner surface of the communicating pipe facing the large passage. It provides an alignment effect to the valve, making its opening/closing operation smooth and preventing uneven wear.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention; FIG. 1 is a side view of an internal combustion engine equipped with the device of the present invention, FIG.
Fig. 4 is a sectional view taken along the - line in Fig. 3, Fig. 5 is a sectional view taken along the - line in Fig. 2, and Fig. 6 is a sectional view taken along the - line in Fig. 3.
The figure is an exploded perspective view of the resonator. DESCRIPTION OF SYMBOLS 1...Internal combustion engine, 2...Intake passage, 5...Resonator, 6...Resonance box, 7...Communication pipe, 7a...
Large passageway, 7b...small passageway, 8...partition wall, 9...on/off valve.

Claims (1)

[Scope of utility model registration request] In an intake noise damping device for an internal combustion engine in which a resonance box is connected to the intake passage of the internal combustion engine via a cylindrical communication pipe, the communication pipe has a large passage with a large cross-sectional area and a small passage with a small cross-sectional area. A partition wall is installed to separate the
This partition wall is curved into a chevron shape with the top protruding toward the main passage and ending before the center of the communication pipe, and is a butterfly type that opens and closes the large passage by rotating around the diameter line of the communication pipe adjacent to the top of the partition wall. An intake noise damping device for an internal combustion engine, characterized in that an on-off valve is pivotally supported on a communication pipe.