JPH05954U - Resonator in engine intake system - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a resonator capable of producing an excellent effect of reducing intake noise over a wide operating region of an engine. A movable wall is provided in a resonance chamber of a resonator connected to an intake pipe of an engine, and the movable wall is displaced according to an operating state of the engine to increase or decrease the volume of the resonance chamber to control the resonance frequency. .. 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]

 Resonators having a common chamber having a constant volume, which is connected to an intake pipe of an engine through a small-diameter inlet pipe, are known. Now, referring to FIG. 1 showing an embodiment of the present invention for convenience, a typical structure of a resonator installed in a conventional intake system for a truck engine will be described. 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 cab (not shown) suspended on the chassis frame. An intake port 16 connected to the pipe 12 through a flexible bellows pipe 14 and an intake port 18 connected to an air cleaner (not shown) are provided, and the bellows pipe 14 is correctly connected to the intake port 16. A guide 20 is provided for this purpose. A resonance chamber 24 is connected to the lower intake pipe 10 via a small-diameter inlet pipe 22. The resonance chamber 24 is different from the configuration according to the present invention shown in the drawing, and conventionally has a cavity having a constant volume. It is a simple container to form.

The resonance frequency f of the resonator 26 having the small-diameter inlet pipe 22 and the resonance chamber 24 as described above is represented by the following mathematical formula 1, as is well known in the art.

[0004]

[Equation 1]

In the above formula 1, c is the speed of sound, d is the inner diameter of the inlet pipe 22, l is the length of the inlet pipe 22, and V is the volume of the resonance chamber 24. This resonator 26 can exhibit an excellent sound deadening effect only in an extremely narrow region near the resonance frequency f expressed by the mathematical formula 1, and as in a truck engine, it has a wide range from idle speed to maximum speed. For an engine operating in the engine speed region, the effect of reducing intake noise can be expected only near a predetermined engine speed that is adjusted in advance. Further, the resonator 26 is often made of a resin material like the lower intake pipe 10, and in this case, in order to manufacture a plurality of types of resonators that are suitable for a plurality of engines having different specifications, Since it is necessary to prepare a large number of molding dies which are essentially expensive, there is a problem that 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]

 To achieve the above object, the present invention has a resonance chamber connected to an intake pipe of an engine through a small-diameter inlet pipe.In the resonance chamber, a movable wall that increases or decreases the volume of the resonance chamber is provided. The present invention proposes a resonator for an engine intake device, which is characterized by being provided.

[0008]

【Example】

 Embodiments of the present invention will be specifically described below with reference to the accompanying drawings. (Note that the matters already described with reference to FIG. 1 regarding the conventional resonator will not be described again.) According to the present invention, the plate-shaped movable wall 28 is provided inside the resin resonance chamber 24. The movable wall 28 is provided with guide grooves 32a and 32b slidably engaged with the guide rails 30a and 30b provided on the top wall 24a and the bottom wall 24b of the resonance chamber 24, respectively. Further, the movable wall 28 has a nut portion 34 at the center thereof, and a screw shaft 36 is screwed into the nut portion 34. One end of the screw shaft 36 is inserted into a lid member 38 attached to the resonance chamber 24, protrudes outside the resonance chamber, and is connected to a motor shaft of a reversible motor 40. The reversible motor 40 is controlled by a controller 42 which receives a signal relating to the operating state of the engine, for example, the rotation speed Ne, and outputs a drive output. According to the above configuration, the reversible motor 40 is driven in the forward or reverse direction for the commanded time by the drive output supplied from the controller 42 according to the operating state of the engine. The rotation of the reversible motor 40 causes the screw shaft 36 to rotate, the movable wall 28 moves together with the nut portion 34 in either the left or right direction in FIG. 1, and the effective volume V of the resonance chamber 24 decreases or increases. By increasing / decreasing the resonance chamber volume V, the resonance frequency f shown in Formula 1 is increased / decreased, and intake noise can be effectively reduced over a wide operating region according to the operating state of the engine. Further, since the volume of the resonance chamber 24 can be increased or decreased as described above, it is possible to easily deal with a plurality of engines having different specifications, and it is possible to reduce the manufacturing cost by sharing the parts. There are advantages.

In the above embodiment, a screw / nut type actuator including a reversible motor, a screw shaft 36, and a nut 34 is shown as an actuator for driving the movable wall 28. However, any other actuator such as an air cylinder may be used. Any actuator can be used.

[0010]

[Effect of the device]

 As described above, the resonator in the intake system of the engine according to the present invention has a resonance chamber connected to the intake pipe of the engine through a small-diameter inlet pipe. It is characterized in that a movable wall that increases or decreases the volume of the engine is provided, and a resonator that can effectively reduce intake noise over a wide operating range of the engine can be provided at a reasonable price, which is practically useful.

[Brief description of drawings]

FIG. 1 is a side view of an embodiment of the present invention, partially shown in section.

FIG. 2 is an enlarged cross-sectional view of main parts taken along the line II-II of FIG.

[Explanation of symbols]

 10 Lower intake pipe 22 Inlet pipe 24 Resonance chamber 26 Resonator 28 Movable wall

Claims (1)

Claims for utility model registration: 1. A resonance chamber connected to an intake pipe of an engine through a small-diameter inlet pipe, wherein the resonance chamber is movable inside to increase or decrease the volume of the resonance chamber. Resonator in the intake system of the engine characterized by having a wall