KR20000055773A - Intake noise reducing system of internal combustion engine - Google Patents

Abstract

PURPOSE: An intake silencer apparatus for an internal engine is provided to achieve an improved ride comfort, reduced cost, and easy assembling work while performing tuning of reduced frequency in proportion to the rotational frequency of engine. CONSTITUTION: An intake silencer apparatus for an internal engine having a pre-cleaner, comprises a variable unit(18) arranged inside a housing of the pre-cleaner so as to ascend/descend by a plate, the variable unit(18) dividing the pre-cleaner into a first chamber(28) and a second chamber(30), and a plurality of variable supporting members(20) for resiliently supporting the variable unit(18). As an amount of air flowing into the pre-cleaner changes in proportion to the rotational frequency of the engine, and the variable unit(18) descends. This causes a change in volume of the second chamber(30), thus reducing a noise generated upon intake of air with respect to a predetermined frequency.

Description

Intake noise reduction device of internal combustion engine {INTAKE NOISE REDUCING SYSTEM OF INTERNAL COMBUSTION ENGINE}

The present invention relates to an intake noise reduction device of an internal combustion engine, and more particularly, to an intake noise reduction device of an internal combustion engine improved to reduce intake noise generated by outside air introduced into a pre-cleaner that is an intake system of an internal combustion engine. will be.

5 is a view showing a prior art, in order to find a problem frequency in order to reduce the noise of the intake machine and to reduce the noise accordingly three to four Helmholtz resonators (2a) (2b) (2C) inflow of air It is attached between the precleaner 4, the air cleaner 6, the air cleaner 6, and the engine 8.

In this case, the intake noise of a specific frequency band is reduced according to the tuning frequency of the resonator 2.

Fig. 6 is a graph showing the relationship between the noise level and the frequency in Fig. 5, showing that the frequency decreases by applying the resonators 2a, 2b, and 2c.

Fig. 7 is a patent application filed by the applicant of the patent 96-64907, in which the resonance plate 10 is provided inside the pre cleaner 4 so that the entire volume can be separated into two, and the resonance plate 10 is connected to the engine 8. By adjusting the height of the precleaner 4 while allowing height adjustment in proportion to the rotational speed, the size of the precleaner 4, which is a resonator including the resonance plate 10, is adjusted to the rotational speed of the engine 8. Since it can be changed in proportion, the intake noise can be significantly reduced.

In the related art, a resonator should be installed for each frequency that requires noise reduction. However, since only three or four resonators are usually installed due to space limitation, it is difficult to eliminate the problem frequency.

And there is a problem in the cost burden due to the installation of three to four resonators.

In addition, since the pre-cleaner is composed of several parts, there is a problem in that the structure is complicated and maintenance is difficult and the cost is burdened.

Therefore, the present invention was created to solve the above-mentioned problems, and an object of the present invention is to raise and lower the intake noise generated by the outside air flowing into the pre-cleaner, which is an intake machine of the internal combustion engine, in proportion to the intake negative pressure of the engine. It is to provide an intake noise reduction device of an internal combustion engine that reduces by changing the volume.

1 is a view showing an intake noise reduction device according to the present invention.

Figure 2 is an enlarged side cross-sectional view showing a pre-cleaner applied to the present invention.

3 shows A-A of FIG. 2;

Figure 4 is a view showing the action of the pre-cleaner applied to the present invention.

5 shows a prior art.

FIG. 6 shows a graph represented by the resonator relative to FIG. 5; FIG.

Figure 7 illustrates the prior art.

The present invention for achieving this in the intake noise reduction device of an internal combustion engine provided with a pre-cleaner,

Variable means of a resonance plate installed in the pre-cleaner housing so as to be lifted and lowered by a plate,

It is to provide an intake noise reduction device of an internal combustion engine comprising a variable support means of a plurality of variable support members provided to support the variable means with an elastic force.

According to the present invention, as the amount of air flowing into the precleaner changes in proportion to the rotational speed of the engine, the variable means is lowered to change the volume, thereby reducing the intake noise for a predetermined frequency generated during intake.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view showing an intake noise reduction device according to the present invention, Figure 2 is an enlarged side cross-sectional view showing a pre-cleaner applied to the present invention.

3 is a diagram illustrating A-A of FIG. 2.

The intake noise reduction device 12 of the internal combustion engine is provided with a pre-cleaner 16 on the front side in order to reduce the intake noise flowing into the air cleaner 14.

The pre cleaner 16 is composed of a resonance plate 18 and a variable support member 20.

The resonance plate 18 is provided to be elevated by a guide 24 formed in the pre-cleaner housing 22, and the resonance plate 18 is formed to communicate with the tube portion 26.

The resonance plate 18 is formed by dividing the precleaner 16 into a first chamber 28 and a second chamber 30.

The variable support member 20 includes a plurality of bolts 32 standing up on the second chamber 30 as variable support means, and a first nut 36 which is fastened after the pipe 34 is inserted into the bolts 32. ) And a second nut 40 to be assembled with the resonance plate 18 installed after the spring 38 is inserted to be supported by the first nut 36.

The second nut 40 and the first nut 36 are fixed to the bolt 32 to control the maximum movement in the vertical direction, and the pipe 34 is secured to the bolt 32 and the spring 38 It is installed for length adjustment.

Referring to Fig. 4, the operation of the present invention made as described above changes in the intake underpressure when the rotation speed of the engine E changes in the intake system of the automobile including the precleaner 16.

Accordingly, while descending while overcoming the elastic force of the spring 38 that adjusts the vertical movement by the pressure of the air acting on the resonance plate 18 of the precleaner 16, while changing the volume (V) of the second chamber (30) It is sucked into the engine E.

In the present invention, since the volume V is changed in proportion to the rotational speed of the engine E, the number of wave numbers is changed to reduce the intake noise and is calculated by the following equation.

Helmholtz equation F (㎐) =

Tube length: L

Pipe cross section: S

Volume: V

Sound transmission speed: C

That is, by changing the volume V using the principle that the intake negative pressure is proportional to the engine speed, the resonance is proportional to the change of the intake negative pressure proportional to the engine speed and the volume V of the precleaner 16 proportional to it. The noise is reduced by changing the frequency by using the noise reduction that is proportional to the frequency and excitation.

Since the reduction frequency is tuned in proportion to the engine speed (engine intake negative pressure), a noise reduction effect can be obtained in the entire frequency range.

As the noise is reduced, the riding comfort of the occupant is improved.

Since the structure of the pre-cleaner is simple, cost reduction is achieved, and as a result, the assembly process is easy.

Claims (5)

In the intake noise reduction device of an internal combustion engine provided with a free cleaner, Variable means of a resonance plate installed in the pre-cleaner housing so as to be lifted and lowered by a plate, Intake noise reduction device of an internal combustion engine, characterized in that it comprises a variable support means of a variable support member is installed to support the variable means with an elastic force. The variable support member according to claim 1, wherein the variable support member is provided with a plurality of bolts erected in the second chamber, a first nut fastened after the pipe is inserted into the bolt, and a spring fitted to be supported by the first nut. An intake noise reduction device of an internal combustion engine, wherein the resonance plate is assembled with a second nut. The intake noise reduction device of an internal combustion engine according to claim 2, wherein the pipe is installed at a predetermined length to stabilize the bolt for adjusting the length of the spring. The intake noise reduction device of an internal combustion engine according to claim 2, wherein the first nut and the second nut are fastened to the bolt and fastened to control the maximum movement in the vertical direction. The intake noise reduction device of an internal combustion engine according to claim 1, wherein a plurality of guides are formed on the inner circumferential surface of the precleaner to easily lift and lower the resonance plate.