CN103382874A - Dual-resonance self-frequency-modulation silencer - Google Patents

Abstract

The purpose of the present invention is to provide a dual-resonance self-tuning muffler, which includes a hollow expansion cavity, and a partition is installed in the expansion cavity, and the partition divides the expansion cavity into a left expansion cavity and a right expansion cavity. Install the inner cannula, the left part of the inner cannula is located in the left expansion cavity, the right part of the inner cannula is located in the right expansion cavity, the left and right parts of the inner cannula are uniformly perforated, and the inner cannula A spring is installed in the right part of the inner tube, the right end of the spring is fixed on the rigid wall surface at the right end of the inner tube, the left end of the spring is connected to the valve, the inlet pipe is arranged on the left expansion chamber, and the outlet pipe is arranged on the right expansion chamber. The invention can automatically and continuously adjust the flow area of the gas according to the engine speed and the exhaust pressure, and then automatically adapt to various working conditions of the engine. power performance requirements.

Description

Double resonance self-tuning muffler

technical field

The invention relates to a muffler, in particular to an engine muffler.

Background technique

Exhaust noise is the most important sound source of automobiles and their engines. The most important, simplest and most effective way to control exhaust noise is to use mufflers. The evaluation index of the muffler mainly has the following three: acoustic performance, aerodynamic performance and structural performance.

The acoustic performance of the muffler requires a sufficiently high noise reduction in the required noise reduction frequency range. The aerodynamic performance requires the muffler to have less resistance to the airflow, and the increased pressure loss after installing the muffler should be controlled within the actual allowable range. If the aerodynamic performance of the muffler is poor and the resistance of the exhaust system is large, the fuel consumption of the internal combustion engine will increase and the output power will decrease. Structural performance requires that the muffler should be small in size, light in weight, simple in structure, easy to process, strong and durable, and have a long service life. The requirements of the above three aspects are indispensable, and they are interrelated and restrict each other. At present, the research on mufflers mainly focuses on the comprehensive study of the acoustic performance and aerodynamic performance of the muffler.

When the engine is running at low speed or decelerating, the gas flow in the exhaust pipe is very small and the flow velocity is low, which has little impact on the dynamic performance of the engine, but the fundamental frequency noise contributes a lot to the engine exhaust noise. The frequency is very low, and the muffler's muffler range is mainly in the low frequency area; when the engine is running at high speed or speeding up, the exhaust volume in the exhaust pipe increases and the flow rate becomes higher, and the aerodynamic performance of the muffler becomes the main factor. considerations. Existing mufflers generally have a single structure, and the internal structure of the muffler does not change during use, and often cannot meet the respective requirements of low frequency and high frequency.

Contents of the invention

The object of the present invention is to provide a dual-resonance self-tuning muffler that can automatically and continuously adjust the gas flow area according to the engine speed and exhaust pressure.

The purpose of the present invention is achieved like this:

The dual-resonance self-tuning muffler of the present invention is characterized in that: it includes a hollow expansion chamber, and a partition is installed in the expansion chamber, and the partition divides the expansion chamber into a left expansion chamber and a right expansion chamber, and a hole is opened in the center of the partition. Install the inner cannula, the left part of the inner cannula is located in the left expansion cavity, the right part of the inner cannula is located in the right expansion cavity, the left and right parts of the inner cannula are uniformly perforated, and the inner cannula A spring is installed in the right part of the inner tube, the right end of the spring is fixed on the rigid wall surface at the right end of the inner tube, the left end of the spring is connected to the valve, the inlet pipe is arranged on the left expansion chamber, and the outlet pipe is arranged on the right expansion chamber.

The present invention may also include:

1. When the spring is in a natural state, the valve covers 2/3 of the perforation area on the right side of the inner cannula.

The advantage of the present invention is that the present invention can automatically and continuously adjust the gas flow area according to the engine speed and exhaust pressure, and then automatically adapt to various working conditions of the engine, and at the same time meet the requirements of the muffler for the muffler when the engine rotates at a low speed and high speed requirements for the power performance of the muffler.

Description of drawings

Fig. 1 is the structural representation of existing muffler;

Fig. 2 is a structural representation of the present invention;

Fig. 3 is a structural schematic diagram of the present invention when the engine rotates at a high speed.

Detailed ways

The present invention is described in more detail below in conjunction with accompanying drawing example:

1-3, the present invention includes an inlet pipe 1, an outlet pipe 2, an intubation pipe 3, a left expansion chamber 4, a right expansion chamber 5, a piston control valve 6 and a spring 7. Wherein the inner insertion tube 3 runs through the two expansion chambers 4 and 5, the perforations 8 are evenly arranged on the left side wall of the inner insertion tube 3 to communicate with the left expansion chamber 4, and the perforations 9 are evenly arranged on the right side wall of the inner insertion tube 3 It communicates with the right expansion chamber 5. The spring 7 is located in the inner tube 3, one side of which is fixed on the rigid wall on the right side of the inner tube 3, and the other side is connected to the valve 6. When the spring is in a natural state, the valve 7 covers 2/3 of the area of the perforation 9 .

When the muffler is in use, gas enters the left expansion chamber 4 from the inlet pipe 1, part of the gas directly enters the inner tube 3 from the left expansion chamber 4, and some gas enters the inner tube 3 through the perforation 8, so that the gas entering the inner The airflow of the intubation tube 3 is more uniform, and can improve the high-frequency noise reduction of the muffler. When the engine is at a low speed, as shown in Figure 2, the gas flow velocity is small, and the air pressure in the inner tube 3 is not enough to compress the spring 7, so the valve 6 is in a closed state, and the gas can only pass through a small opening area 9 Entering the right expansion cavity 5, the radiation area of the gas is small at this time, and the low-frequency noise reduction effect of the muffler is better. With the gradual increase of the rotational speed, the fundamental noise frequency of the engine gradually moves to high frequency, the spring 7 is gradually compressed, the valve 6 is gradually moved to the right, the area of the perforation 9 is gradually increased, and the radiation area of the gas is gradually enlarged , the anechoic frequency band of the muffler gradually moves to high frequency.

When the engine is at a high speed, as shown in Figure 3, the increase of the gas flow rate increases the gas pressure in the inner tube 3, compresses the spring 7, and increases the distance that the valve 6 moves to the right. The higher the engine speed, the more the spring 7 is compressed, the larger the area of the perforation 9 is opened, and the gas in the inner tube 3 enters the right expansion chamber 5 through more perforation areas, and then enters the outlet pipe 2. At this time, the flow resistance of the air is reduced, thereby reducing the pressure loss of the muffler and the power loss of the engine, thereby ensuring the power performance of the engine. After the valve 6 is opened, although the amount of air noise generated in the tailpipe due to the high-speed operation of the engine increases, the noise generated by air flow friction due to the increase of the gas flow area decreases. Moreover, at high rotational speeds, airflow friction noise is the main component of tailpipe noise, so unobstructed gas flow may actually reduce the overall noise.

In this way, the muffler can automatically and continuously adjust the flow area of the gas in the intubation pipe 3 according to the speed of the engine, which can not only ensure that the exhaust noise will not be too large when the engine is running at a low speed, but also ensure that the power loss of the engine will not increase with the speed of the engine. increases with the increase.

Claims (2)

1. double resonance is from the frequency modulation silencing apparatus, it is characterized in that: the expansion chamber that comprises hollow, dividing plate is installed in expansion chamber, dividing plate is separated into left expansion chamber and right expansion chamber with expansion chamber, the dividing plate center has the hole, interpolation pipe is installed in the hole, the left part of interpolation pipe is positioned in left expansion chamber, the right side part of interpolation pipe is positioned in right expansion chamber, the left part of interpolation pipe and right side part evenly have perforation, in the right side part of interpolation pipe, spring is installed, the spring right-hand member is fixed on the rigid plane of interpolation pipe right-hand member, the spring left end connects valve, on left expansion chamber, inlet tube is set, on right expansion chamber, outer pipe is set.

2. double resonance according to claim 1 from the frequency modulation silencing apparatus, is characterized in that: when spring in the raw the time, valve covers 2/3 of interpolation pipe right side part perforation field.

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