JPH05953U - Inspirator resonator - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a resonator capable of producing an excellent effect of reducing intake noise over a wide operating range of an engine. In a resonator in which a resonance chamber is connected to an intake pipe of an engine via a communication pipe having a small diameter, the communication pipe is provided with passage area control means for changing a passage area according to an engine speed. Is characterized by. With this configuration, it is possible to reduce the intake noise by changing the resonance frequency over a wide operating range of the engine.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a resonator in an intake system of an engine.

[0002]

[Prior Art]

 A resonator having a common chamber having a constant volume, which is connected to an intake pipe of an engine through a communication pipe having a small diameter, is known. Now, a typical structure of a resonator installed in a conventional intake system for a truck engine will be described with reference to FIG. 1 showing an embodiment of the present invention for the sake of convenience. A lower intake pipe made of resin mounted on a chassis frame (not shown), the lower intake pipe being an upper intake pipe attached to a rear wall of a cabin (not shown) mounted on the chassis frame. An intake inlet 16 connected to the pipe 12 through a flexible bellows pipe 14 and an intake outlet 18 connected to an air cleaner (not shown) are provided, and the bellows pipe 14 is properly connected to the intake inlet 16. A guide 20 is provided for this purpose. A resonance chamber 24 is connected to the lower intake pipe 10 via a communication pipe 22 having a small diameter. The communication pipe 22 does not include the passage area control means A according to the present invention shown in the figure, and is a simple circular pipe having a constant cross-sectional area in the past.

As is well known in the art, the resonance frequency f of the resonator 26 including the small diameter communication pipe 22 and the resonance chamber 24 as described above is represented by the following formula 1.

[0004]

[Equation 1]

In the above formula 1, C is the speed of sound, d is the inner diameter of the communication tube 22, l is the length of the communication tube 22, and V is the volume of the resonance chamber 24. This resonator 26 can exert an excellent silencing effect only in an extremely narrow region near the resonance frequency f 1 expressed by the mathematical formula 1, and as in a truck engine, it has a wide rotation range from idle speed to maximum speed. For an engine that operates within several ranges, the effect of reducing intake noise can be expected only near a predetermined rotational speed that is adjusted in advance. Further, the resonator 26 is often made of a resin material like the intake pipe 10 described below. In this case, in order to manufacture a plurality of types of resonators which are suitable for a plurality of engines having different specifications, Since a large number of molding dies that are essentially expensive must be prepared, the manufacturing cost of the resonator increases.

[0006]

[Problems to be solved by the device]

 The present invention was devised in view of the above circumstances, and is capable of reducing intake noise in a wide range of engine revolution speeds, and is inexpensive as a resonator that can be widely applied to engines of various specifications. It is intended to be provided to.

[0007]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention has a resonance chamber connected to an intake pipe of an engine through a communication pipe having a small diameter, and the cross-sectional area of the communication pipe depends on the number of revolutions of the engine. The present invention proposes a resonator for an intake device, which is characterized in that it is provided with a passage area control means for changing it.

[0008]

【Example】

 Embodiments of the present invention will be specifically described below with reference to the accompanying drawings. (Note that re-statement of the matters already described with reference to FIG. 1 regarding the conventional resonator will be omitted.) According to the present invention, the passage area control for controlling the passage area of the communication pipe 22 of the resonator 26 is performed. Means A are provided. The passage area control means A is a disc-shaped passage member 30 in which a plurality of circular passages 28a, 28b, 28c and 28d having different cross-sectional areas are arranged on substantially the same circumference, and is fixed to the passage member 30. It includes a central shaft 32 integrally formed and a motor 36 connected to the central shaft 32 via a gear pair 34. The motor 36 is controlled by a controller 38 which receives a signal Ne relating to the number of revolutions of the engine and outputs a drive output.

According to the above configuration, the motor 36 is driven by the drive output supplied from the controller 38 according to the engine speed. The rotation of the motor 36 is transmitted to the central shaft 32 via the gear pair 34, and the circular members 28a to 28d instructed by the rotation of the passage member 30 are aligned with the communication pipe 22 and the lower intake pipe 10. The passage area connecting the resonance chamber 24 is set according to the engine speed. As the passage area of the communication pipe 22 increases or decreases, the resonance frequency f shown in the above formula increases or decreases, and intake noise can be effectively reduced in a plurality of engine speed regions. In the above embodiment, the passage member 30 is provided with the four circular passages 28a to 28d, but the intake noise is reduced at a higher engine speed by further increasing the number of circular passages. be able to.

Further, by changing the size of the passage member 30 and the cross-sectional area of the circular passage without changing the shape and the size of the resonator 26, it is possible to easily obtain a plurality of types of engines having different specifications. Since this is possible, there is an advantage that the manufacturing cost of the resonator 26 can be reduced. Further, instead of the passage member 30, for example, a variable diaphragm device of the same type as that widely used in the exposure control diaphragm device of a photographic machine can be provided in the communication pipe 22. In this case, the rotation of the engine is prevented. There is an advantage that the passage cross-sectional area of the communication pipe 22 can be controlled steplessly according to the number.

[0011]

[Effect of the device]

 As described above, the resonator of the intake device according to the present invention has a resonance chamber that is connected to the intake pipe of the engine through a communication pipe having a small diameter. It is characterized in that it is provided with a passage area control means that changes according to the engine speed, and a resonator that can effectively reduce intake noise over a wide operating range of the engine can be provided at low cost. Therefore, it is practically useful.

[Brief description of drawings]

FIG. 1 is a side view showing an embodiment of the present invention.

FIG. 2 is an enlarged front view showing a passage member extracted from FIG.

[Explanation of symbols]

 10 Lower intake pipe 22 Communication pipe 24 Resonance chamber 26 Resonator 30 Passage member

Claims (1)

Claims for utility model registration: 1. A resonance chamber connected to an intake pipe of an engine through a communication pipe having a small diameter, wherein the communication pipe has a cross-sectional area which corresponds to the rotational speed of the engine. A resonator for an air intake device, characterized in that it is provided with a passage area control means that changes in accordance with it.