JPS59108861A - Resonator - Google Patents

Abstract

PURPOSE:To increase the output in the all revolution range of an internal-combustion engine by varying the sectional area of the opening of a tubular member which communicates to an intake duct and a resonance chamber. CONSTITUTION:The revolution signal of an internal-combustion engine (e.g., obtained from a distributor or a crank pulley, etc.) is input into a control computer 20, and the number of engine revolution is read-out in the computer 20, and the dominant frequency component of the intake noise in each revolution is calculated. In order to obtain the resonance frequency corresponding to the above-described frequency component, a driving signal is sent into an actuator 18 to revolve a block 15b through a shaft 19, and resonance frequency is varied.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a resonator that allows a resonant frequency to be synchronized to the rotational speed of an internal combustion engine.

- A conventional resonator was constructed as shown in FIG.

That is, the conventional resonator 17 is installed in the middle of the intake duct 13 and is composed of a tubular member 15 that communicates with the inner suction passage 14 of the intake duct 13, and a resonance chamber 16 in which the end surface of the tubular member 15 is open. was.

The resonant frequency fP of this resonator 17 is rp=C
/ 2 yr S/V-Rp-...if) Claim 11!
+UtLru.

(S-πD 2/ 4.I2p = 1 +o, s D
) Here, S is the opening cross-sectional area of the communicating tubular member, D is the inner diameter of the communicating tubular member 15', l is the length of the communicating tubular member 15',
(2) is the internal volume of the resonance chamber 16'.

Therefore, in the conventional resonator, due to its structure, the resonant frequency f
P was fixed uniformly, and a damping effect was obtained only at that specific resonance frequency fP.

In contrast to conventional resonators that can obtain only a specific single resonant frequency, the present invention makes the resonant frequency variable by changing the length i of the communicating tubular member shown in equation (1), and allows controllable frequency range. The purpose is to expand the

That is, (in order to change the resonance frequency using equation 11, the shape of the communicating tubular member, that is, the inner diameter D1 and length 7 of the tubular member)
! Although P1 or the volume of the resonance chamber (2) may be made variable, we believe that making the cross-sectional area S of the opening of the tubular member variable is the easiest and most compact method, and in the present invention, the cross-sectional area S of the opening of the tubular member is made variable. This configuration is adopted.

An embodiment in which the present invention is used as an intake noise muffling device in an internal combustion engine intake system will be described below with reference to FIG.

In the figure, 1 is a cylinder in which a piston 2 is slidably fitted.
Its upper part is covered with a cylinder head 3, and the cylinder head 3 is formed with an intake valve 4, an intake port 6 which is periodically opened and closed by an exhaust valve 5, and an exhaust lower. The exhaust lower communicates with an exhaust pipe via an exhaust passage 8, and this exhaust pipe is provided with a muffler (not shown) for muffling exhaust noise.

On the other hand, the intake port 6 is connected to an intake passage 9 and a capretor 10 (
In the case of a diesel vehicle, the carburetor 10 is not present) and is connected to an air cleaner 11 that purifies intake air. A suction pipe 12 is attached to the upstream end of the air cleaner 11, an intake duct 13 is connected to the tip of the suction pipe 12, and a tip opening 13a of the intake duct 13 is open to the atmosphere.

A tubular member 15 branches off in the middle of the suction pipe 12 or the suction duct 13 (intake duct 13 in this embodiment). One end of the tubular member 15 communicates with the suction passage 14 in the intake duct 13, and the other end opens into a resonance chamber 16 which is a closed space. A resonator 17 is formed by the tubular member 15 and the resonance chamber 16.

The tubular member 15 has a double tube structure, and its details will be explained in Section 3. It is shown in Figure 4. The annular member 15 includes a cap 15f having a predetermined opening, an outer tubular member 15a to which the cap 15f is attached at both ends, a side plate 15C fixed to the camp 15f, and a semi-cylindrical member disposed inside the outer tubular member 15a. 15b. The air passage of the tubular member 15 is formed by the inner wall of the outer tubular member 15a and the wall surface of the block 15b. Therefore, by rotating and sliding the block 15b, it is possible to change the cross-sectional area of the ventilation passage. the law of nature)
One end of the side tubular member 15a is fixed to the intake duct 13,
The other end is fixed to the resonator 17. The block 15b is fixed via a shaft 19 to an actuator 18 which is fixed to a surface of the resonance chamber 16 on the opposite side to the outer tubular member 15a and operates in a rotational direction. The outer tubular member 15a, the block 15b, and the intake duct 13 are blow-molded resin products. Therefore, the above-mentioned intake duct 13,
The outer tubular member 15a and the resonator 17 are fixed by appropriate means such as adhesive screwing, tightening, welding, etc.

Then, the control computer 20 calculates a resonance frequency in synchronization with the engine rotation based on a rotation signal from a rotation detector (not shown) of the internal combustion engine, and an electric signal based on the calculation is applied to the linear actuator 18. It looks like this. Therefore, the shaft 19 of the actuator 8
The block 15b fixed to the outer tubular member 15a is rotated by an amount corresponding to an electric signal from the computer 20 using the inner wall of the outer tubular member 15a as a guide. Furthermore, in block 15b,
A hole for fixing the shaft 19 of the actuator 18 is provided, and a guide hole 15d is provided in the cap 15f fixed to the outer tubular portion side 15a. The shaft 19 has a hole 15e.

15d is fixed by screwing, tightening, etc. The block 15b also includes the outer tubular member 15.
Its circumferential outer surface is in contact with the inner wall of a to prevent air leakage, and its dimensions are such that it can rotate.

Next, a method of varying the resonance frequency using the resonator 17 will be explained. FIG. 5 illustrates the relationship between the opening area S of the tubular member and the resonant frequency when the resonance chamber volume V = 2000 cc and the length ilP of the annular member is constant. From Fig. 5, if the length of the tubular member is j!p = 30 mm, the resonant frequency fP when the tubular member opening cross-sectional area S = 461 mJ is 150 Hz, and when the opening cross-sectional area is increased to S-820++J, the resonance frequency fP is 150 Hz. It can be seen that the frequency fp can be increased to 200 Hz, and conversely, if the aperture cross-sectional area S is decreased to 205 mdt, the resonance frequency fP can be lowered to 100 Hz.

Therefore, the required upper limit resonant frequency fup is determined when the length of the communicating tubular member 15 is at its maximum, that is, between the predetermined opening area SO of the gear knob 15f shown in FIG. 6 and the inner wall of the outer tubular member 15a. This is obtained when the cross-sectional area S of the ventilation path formed by the opening side wall of the inner tube block 15b and the side plate 15c is equal. and inner tubular block 15b
is linked to the actuator 1, and as this rotates and slides, the air passage area S formed by the three walls is narrowed, so the lower limit resonance frequency fl.

W is determined by the cross-sectional area S of the ventilation passage determined by the three wall surfaces when the inner tubular block is rotated by the maximum amount θ° from the initial setting as shown in FIG.

Next, a specific resonant frequency range will be calculated based on the above-mentioned FIG. For example, the length of the tubular member is β-3Q van, the predetermined opening cross-sectional area of the outer tubular member is 5o=525y+J,
When the rotation angle of the actuator is set to β-1Q8°,
The minimum cross-sectional area of the air passage is S=205 m1, the upper limit resonant frequency fup is 160 Hz, and the lower limit resonant frequency flow is 100 Hz. Therefore, according to this example, block 1
By rotating and sliding 5b, the resonance frequency is increased to 10
It can be continuously varied from 0 Hz to 160 Hz.

Of course, in the above example, the resonance chamber volume V=2000CC and the tubular member length 7! = 30 mm, but by appropriately selecting both of them, the rotation angle θ of the same actuator can be changed.
The variable range of the resonant frequency can be set to a desired range. Furthermore, by further increasing the predetermined opening cross-sectional area So of the outer tubular member, that is, the inner diameter of the tubular member, the variable resonance frequency range can be increased.

Next, an example will be described in which the resonator 17 that performs the above operation is actually used in synchronization with the rotational speed of the internal combustion engine.

As shown in FIG. 2, a rotation signal of the internal combustion engine (obtained from a distributor or a crank pulley, etc.) is input to a control computer 20 using a microcomputer, and the engine rotation speed is read within the computer 20. Calculate the dominant frequency components of the intake noise. Then, a drive signal is sent to the actuator 18 to rotate the block 15b via the shaft 19 to change the resonance frequency so that a resonance frequency corresponding to the frequency component is obtained. A flowchart showing the above control method is shown in FIG.

In order to control in this way, it is possible to move the linear actuator 18 in the forward and reverse directions even when the rotational speed of the internal combustion engine increases or decreases, so that the resonance frequency can always be varied in synchronization with the rotational speed. can.

Furthermore, as a method of synchronizing the engine speed, as shown by the solid line in FIG.
Alternatively, synchronization can be performed stepwise as shown by the broken line, or synchronization can be performed freely by a control computer.

FIG. 10 shows the effect of reducing intake noise by using the resonator 17 in an internal combustion engine. The thin line A in the figure is the intake noise when the resonator 17 is not installed, which is 4000 as is clear from the figure.
There is a large noise peak around 4,800 rpm, which has become a problem. This noise peak is dominated by the second-order component of the engine speed, that is, from 133 Hz to 160 Hz. Therefore, the resonant frequency variable range of the resonator 17 is 1°OH at the rotation angle θ-18° of the linear actuator 18 described above.
By selecting specifications that can be varied from Z to 160 Hz and synchronously varying the engine speed from 3,000 to 4,800 revolutions, as shown by the thick line C in the figure, it is possible to replace the conventional resonator installation (the dot-dashed line in the figure ), it is possible to significantly reduce intake noise.

Note that the resonator 17 of this example can also provide the following effects.

In other words, if the natural resonance frequency of the intake air passage pipe of the intake system matches the opening/closing frequency of the intake valve, a large amount of mixed gas (
It is well known that the internal combustion engine (fuel and intake air) is drawn into the cylinder.For this reason, in the past, the length of the intake pipe was selected to obtain resonance at a certain rotational speed of the internal combustion engine, and the engine output at that rotational speed was is increasing.

Therefore, by installing the resonator 17 in the middle of the suction pipe and making its resonance frequency variable, the natural resonance frequency of the entire suction pipe can be changed and synchronized with the opening/closing timing of the suction valve 4. It can also act as a means to increase the output in the entire rotation range of the internal combustion engine.

Although the above-mentioned examples are preferred embodiments of the present invention, the present invention includes various embodiments other than the above-mentioned embodiments.

That is, in the above example, the actuator 18 is installed in the resonance chamber 16, but it may be installed on the intake duct 13 side as shown in FIG. Furthermore, as shown in FIG. 12, it is also possible to separate the resonator mounting portion 21 from the intake duct 13 in consideration of the ease of mounting, so that the mounting position thereof can be changed freely.

Furthermore, in the above-described embodiment, the outer communicating tubular member 15a initially had one opening, but as shown in FIG.
Radially dispersed and chrysanthemum-shaped tubular blocks 1
5b, the opening cross-sectional area of the communicating tubular member may be varied.

Furthermore, in the above-described embodiment, the resonator 17 was disposed in the intake system and used as a method for reducing intake noise.
The same effect can be achieved even if the exhaust system is installed in the exhaust system as an exhaust noise reduction device.

As explained above, in the resonator of the present invention, the cross-sectional area of the opening of the communicating tubular member of the resonator is changed by the actuator in synchronization with the engine speed, so that the resonant frequency can be made variable. An excellent effect can be obtained in that the frequency range in which the resonance effect can be obtained can be made larger than that of conventional resonators.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing a conventional resonator, Fig. 2 is a configuration diagram showing an embodiment of the resonator of the present invention installed in an internal combustion engine, and Fig. 3 is a communication diagram of the resonator shown in Fig. 2. A perspective view showing the tubular member; FIG. 4 is an exploded perspective view of the delivery tubular member shown in FIG. 3;
FIG. 5 is an explanatory diagram showing the relationship between the shape of the communicating tube member of the resonator and the resonant frequency, FIGS. 6 and 7 are cross-sectional views showing how the resonant frequency is changed by the resonator shown in FIG. 2, and FIG. Control flow chart Figure 9 is an explanatory diagram showing a method of synchronizing the engine speed and resonance frequency, Figure 10 is an explanatory diagram showing the intake noise reduction effect of the resonator shown in Figure 2, and Figures 11 and 12 are respectively FIG. 13 is a sectional view showing another embodiment of the resonator of the present invention, and FIG. 13 is an exploded perspective view showing essential parts of still another embodiment of the resonator of the present invention. 1... Internal combustion engine cylinder, 4... Intake valve, 5...
Exhaust valve, 6... Intake port, 9... Intake passage, 12...
・Suction pipe, 13... Intake duct, 14... Suction path,
15... Communication tubular member, 15a... Outer communication tubular member, 15b... Block, 16... Resonance chamber, 17.
... Resonator, 18... Actuator, 20... Control computer. Representative Patent Attorney Takashi Okabe Figure 1 Figure 2 Figure 3 Figure 5 A a, I+Ifil 31 'Fi Hx No. 6
Figure 7 Figure 8 'Ishikaku@Chit! X (r, pm) Figure 10 Figure 11 Figure 12 36

Claims (1)

[Scope of claims] a cap provided at an end of the member and having a predetermined opening; a block rotatably disposed within the outer communicating tubular member and varying the opening area of the cap with rotation; a resonator comprising a linear actuator that displaces the block based on the internal combustion engine; and a control computer that detects the rotational speed of the internal combustion engine and controls an electric signal output to the linear actuator. (2) One end of the outer communicating tubular member. 2. The linear actuator according to claim 1, wherein the control computer calculates a resonant frequency according to the rotational speed of the internal combustion engine, and outputs an electric signal to the linear actuator to obtain the resonant frequency. (3) As described above, one end of the side communicating tubular member opens to the intake pipe, and the control computer calculates a resonance frequency corresponding to the opening/closing frequency of the intake valve of the internal combustion engine, and obtains the resonance frequency. 2. The resonator according to claim 1, wherein the resonator outputs an electric signal to the linear actuator.