JPH08158964A - Variable resonator - Google Patents

Abstract

PURPOSE: To remove a movable part with sliding and rotation, and to eliminate the difficulty of keeping the airtightness by fitting an elastic bag formed by an elastic film, where oil is sealed to the inner wall of a resonating chamber of a resonator, and connecting the elastic bag to a variable oil pressure source outside the resonating chamber by an oil pressure hose, so that the elastic bag is expanded and contracted by the change of oil pressure. CONSTITUTION: A resonator 1 comprises a communicating pipe 5 and a resonating chamber 6, wherein an elastic bag 7 (rubber bag) where oil is sealed is placed in the resonating chamber 6. When oil pressure of an oil pump 8 of an internal combustion engine 2 is transmitted through an oil pressure hose 9 to the elastic bag 7 to be expanded, the capacity of the cavity of the resonating chamber 7 is decreased to change the silencing characteristic. Accordingly, as the movable part of a shaft or the like which passes through the resonating chamber or the like is not provided, there is no difficulty of keeping airtightness. If an oil pump of an internal combustion engine is used as a variable oil pressure source, linear silencing characteristic control can be conducted without the need of a special driving mechanism and a signal control means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable resonator provided in an intake system of an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, there has been a system in which a resonance chamber is connected to an air duct through a communication pipe to change the resonance chamber volume to change the resonance frequency. For example, the actual development 61-418
The one disclosed in Japanese Patent No. 16 discloses a partition wall provided in the resonance chamber for opening and closing a valve provided in this partition. In such a device, the volume change of the resonance chamber is changed in several steps. And is not continuous. In addition, the operation mechanism of the plurality of valves is complicated. Therefore, as disclosed in Japanese Utility Model Laid-Open No. 1-174562, a slidable piston-shaped partition plate is provided in a cylinder-shaped resonance chamber, and this is operated and slid from the outside to continuously resonate the resonance chamber. A variable volume has been proposed.

[0003]

In all of the above, the volume changing means such as the valve and the piston are operated by the drive shaft, and it is possible to maintain the airtightness of the sliding part and the rotating part between the shaft and the resonance chamber wall. It is difficult, and leakage of air causes leakage of noise and deviation of silencing characteristics. On the other hand, in the latter case, it is difficult to maintain the airtightness of the sliding portion of the piston, and the desired silencing characteristic cannot be obtained with respect to changes in the volume of the resonance chamber. This is particularly likely to occur when the resonance chamber is made of synthetic resin.

[0004]

According to the present invention, a bag-shaped elastic bag made of an elastic film and containing oil is attached to the inner wall of a resonance chamber, and the variable hydraulic source outside the resonance chamber is connected by a hydraulic hose. Is.

[0005]

[Operation] The change in the hydraulic pressure of the variable hydraulic power source is transmitted to the oil in the elastic bag through the hydraulic hose, and when the hydraulic pressure rises, the oil is sent into the elastic bag according to the hydraulic pressure, and the elastic bag elastically moves according to the hydraulic pressure. Expands. In this way, the cavity volume of the resonance chamber decreases and increases in accordance with the expansion and contraction of the elastic bag due to the change in hydraulic pressure.

[0006]

EXAMPLE FIG. 1 shows an example. The variable resonator 1 is attached to the intake duct 4 on the downstream side of the air cleaner 3 of the internal combustion engine 2 and includes a communication pipe 5 and a resonance chamber 6. An elastic bag 7 made of a rubber bag having elasticity is attached to the inner wall of the resonance chamber 6 in an oiltight manner at the opening edge. The attachment means may be a fixing frame fixed and a sealant applied, or an adhesive may be used, and pressure resistance may be provided by an appropriate means. The elastic bag 7 is filled with oil of the same quality as the engine oil, and is connected to the oil pump 8 by a hydraulic hose 9 branched from the discharge pipe of the oil pump 8 of the internal combustion engine 2. The oil pump 8 is a variable hydraulic power source.

The oil pump 8 is driven by the operation of the internal combustion engine 2.
Oil pump 8 also operates as the engine speed increases.
Since the number of revolutions also increases and the hydraulic pressure increases, pressure oil is fed into the elastic bag 7. As a result, the elastic bag 7 has a chain line 1
It expands like 0 and reduces the volume of the cavity portion of the resonance chamber 6. The volume of the cavity changes according to the continuous change of the hydraulic pressure fluctuation, and the resonance characteristic changes continuously. In the case of an internal combustion engine, the main noise frequency to be silenced increases as the rotational speed increases, and accordingly, the resonance chamber volume is reduced and the resonance frequency is changed to a higher one, which is very convenient. Further, in this example, since the oil pump of the internal combustion engine is used as the variable hydraulic pressure source, no other power is required and the device is simple.

[0008]

The variable resonator according to the present invention does not require a mechanism for moving the rotary shaft, the sliding push rod, etc. through the wall defining the resonance chamber, etc., so that there is no need to consider maintaining airtightness and the performance is stable. However, performance control is easy. Further, when the oil pump of the internal combustion engine is used as the variable hydraulic pressure source, no special drive mechanism, signal control means, etc. are required, and linear control can be easily performed.

[Brief description of drawings]

FIG. 1 is a diagram showing an example.

[Explanation of symbols]

 5 Communication pipe 6 Resonance chamber 7 Elastic bag 8 Oil pump 9 Hydraulic hose

Claims (1)

[Claims] 1. A resonator provided with a hollow resonance chamber connected to an air duct through a communication pipe, wherein a bag-shaped elastic bag made of an elastic film and containing oil is attached to the inner wall of the resonance chamber. A variable resonator that connects the inside and a variable hydraulic source outside the resonance chamber with a hydraulic hose.