Patent Publication Number: US-2007095605-A1

Title: Muffler for vehicle

Description:
TECHNICAL FIELD  
      The present invention relates to a muffler for vehicle, being capable of augmenting engine&#39;s output power more than conventional tuning mufflers and more effectively eliminating exhaust noise.  
     BACKGROUND ART  
      A muffler, generally installed at the outlet of an exhaust pipe connected to an exhaust manifold, is a device that eliminates exhaust noise by reducing the pressure of exhaust gas from an engine. Mufflers are roughly divided into a dilation type, an absorption type, and a partition type. Of these, the partition type is generally used for conventional pure parts.  
      In the partition type muffler having multiple isolating partitions in it, the exhaust gas is step-wise reduced while passing the isolating partitions, and therefore, the partition type muffler has better noise elimination capability compared to other type mufflers. However, since the isolating partitions in itself impede or resist the flow of the exhaust gas, the engine output power is accordingly reduced.  
      Recently, many automobile maniacs like to tune or replace the original muffler to increase the engine output power at the sacrifice of noise elimination.  FIG. 1  shows a cross section of a certain replacement muffler. As shown, the replacement muffler  10  is composed of a casing  1 , whose one end is fixed to an exhaust manifold  7  and the other end is connected to an outlet; a multi-punctured pipe  2 , located in the casing  1  and connected to the exhaust manifold  7 , for forming therein an exhaust gas passing channel  4 ; and a sound absorbing material  6 , filled in the casing  1  and wrapping the multi-punctured pipe  2 .  
       FIG. 2  shows the multi-punctured pipe  2  that has a plurality of holes  3  on its circumference. Explosion sound, especially high frequency sound, from the engine spouts from the holes  3  and absorbed into the sound absorbing material  6  in the middle of passing the exhaust gas passing channel  4 . It is noted that the exhaust gas passing channel  4  is completely open such that no hindrance pressure against the exhaust gas from the engine is generated.  
      In the conventional muffler, since there is no obstacles in the exhaust gas passing channel  4 , the exhaust gas can freely pass the channel  4  in the direction of ‘a’, but, for the same reason, the exhaust noise freely gives off the muffler also. In addition, since the exhaust gas passing channel  4  is always open to the atmosphere, the temperature in a combustion room of the engine becomes abnormally lower.  
     DISCLOSURE OF INVENTION  
      The present invention is invented to overcome the conventional tuning muffler&#39;s drawbacks. It is an object of the present invention to provide a muffler for vehicle that generates output power more than the conventional tuning muffler, and also increases the noise elimination capability more than convention partition type muffler.  
      It is another object of the present invention to provide a muffler for vehicle that prevents the temperature drop in the engine&#39;s combustion room occurring in the conventional muffler because the exhaust gas passing channel is always open to the atmosphere.  
      To achieve the above object, there is provided a muffler for vehicle comprising:  
      exhaust pressure control means connected to an exhaust manifold of an vehicle engine, for controlling pressure of the exhaust gas,  
      the exhaust pressure control means comprising an exhaust pressure control plate, which is pivotally attached to a predetermined position of the exhaust pressure control part, and  
      noise elimination means, which shapes generally a hollow pipe and is connected to the exhaust pressure control means part,  
      the noise elimination means comprising a mesh pipe, through which the exhaust gas passes; a sound absorber enveloping the mesh pipe; and a casing enclosing the sound absorber, whose one end is connected to the exhaust pressure control means and the other end is connected to an outlet.  
      According to another feature of the present invention, there is provided a muffler for vehicle comprising  
      noise elimination means, which shapes generally a hollow pipe and is connected to the exhaust pressure control means part, the noise elimination means comprising a mesh pipe, through which the exhaust gas passes; a sound absorber enveloping the mesh pipe; and a casing enclosing the sound absorber, whose one end is connected to the exhaust pressure control means and the other end is connected to an outlet,  
      exhaust pressure control means connected to an exhaust manifold of an vehicle engine, for controlling pressure of the exhaust gas,  
      the exhaust pressure control means comprising an exhaust pressure control plate, which is pivotally attached to a predetermined position of the exhaust pressure control part, and  
      at least one second noise elimination means connected to said noise elimination means, the second noise elimination means having the same construction as said noise elimination means.  
      It is preferable that the sound absorber is formed by piling at least two different sound absorbing materials, and the exhaust pressure control plate is located near the location of the engine. It is also preferable that the mesh pipe is dense so as not to be seen through it. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The above and other objects, features, and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings, in which:  
       FIG. 1  is a longitudinal cross-section of a conventional muffler,  
       FIG. 2  is a perspective view of a multi-punctured pipe in  FIG. 1 ,  
       FIG. 3  is a longitudinal cross-section of one embodiment of the present invention,  
       FIG. 4  is a detailed view of A-A section in  FIG. 3 ,  
       FIG. 5  is a front view of an exhaust pressure control plate of the embodiment of the present invention,  
       FIG. 6  is a perspective view of a mesh pipe of the embodiment of the present invention,  
       FIG. 7  is an exploded view of the mesh pipe of the embodiment of the present invention,  
       FIG. 8  is a perspective view of another embodiment of the present invention,  
       FIG. 9  is a perspective view of still another embodiment of the present invention,  
       FIG. 10  is a perspective view of yet another embodiment of the present invention, 
    
    
     PREFERRED EMBODIMENTS FOR CARRYING OUT THE INVENTION  
       FIG. 3  is a longitudinal cross-section of one embodiment of the present invention, and  FIG. 4  is an A-A cross-section view from  FIG. 3 . As shown in  FIG. 3 , a muffler according to the embodiment of the present invention, is composed of an exhaust pressure control part  20  connected to the exhaust manifold of the engine, and a noise elimination part  25  connected to an opposite end of the exhaust pressure control part  20 . An opposite end of the noise elimination part  25  is connected to an outlet  27  which emits the exhaust gas from the engine to the atmosphere.  
      The exhaust pressure control part  20  includes therein an exhaust pressure control plate  21  which is pivotally attached to a certain position of the top of the exhaust pressure control part  20 . It is preferable that the exhaust pressure control plate  21  is positioned near the engine.  FIG. 5  is a front view of the pressure control plate  21 , which shows a plurality of exhaust holes  28 . The exhaust holes may be one or several larger holes, unlike many small holes depicted in  FIG. 5 .  
      The noise elimination part  25  is composed of a mesh pipe  22 , through which the exhaust gas passes; a sound absorber  23  enveloping the mesh pipe  22 ; and a casing  24  enclosing the sound absorber  23 . The mesh pipe  22  is an element that replaces the multi-punctured pipe  2  shown in  FIGS. 1 and 2 . The mesh pipe  22  is depicted in  FIG. 6 .  
      Unlike the conventional multi-punctured pipe  2  in which a plurality of holes are penetrated, the mesh pipe  22  according to the present invention is constructed by a mesh sheet  22   a  (see  FIG. 7 ). The mesh sheet  22   a , made of a dense wire net, is cylindrically rolled and the lateral ends are capped by fixing means  22   b  to be fixed to the cylindrical shape. It is preferable that the mesh sheet  22   a  is dense so as not to be seen through it. By replacing the multi-punctured pipe  2  to this mesh pipe  22 , both the noise elimination efficiency and the engine output power can be increased. In addition, since the dimension of the mesh pipe  22  is relatively smaller, the dimension of the whole muffler may be decreased.  
      The sound absorber  23  eliminates the explosion sound of the exhaust gas, in which three different sound absorbing materials are piled: for example, a stainless steel wool  23   a  which adjoins the mesh pipe  22 ; a ceramic wool  23   b  in the intermediate layer; and a rock wool  23   c  in the outermost layer. The stainless steel wool  23   a  plays a role in absorbing the exhaust sound, protecting the other absorbing materials, and malting the exhaust sound mellow even in the long term use. The ceramic wool  23   b  is an excellent sound absorbing material that has the good heat-endurability and is strong dampproof. The rock wool  23   c  is also an excellent sound absorbing material. The structure of the above sound absorber  23  is just an example, and those who skilled in the relevant art may construct the sound absorber by using other materials.  
      In the mean time, the mesh pipe  22  shown in  FIG. 6  may be warped by high temperature of the exhaust gas, since the mesh pipe  22  is made of a pliable material. For prevention, a conventional multi-punctured pipe (see  FIG. 2 ) may be inserted in the mesh pipe  22  to reinforce it. Since the hole diameter of the multi-punctured pipe  2  is much smaller than that of the mesh pipe  22 , the multi-punctured pipe  2  does not have an effect on the sound elimination capability of the muffler of the present invention. It is used just for reinforcing the pliable mesh pipe  22 .  
      Now the operation of the above-structured embodiment will be described. If the exhaust gas from the engine&#39;s exhaust manifold is introduced to the exhaust pressure control part  20 , the exhaust pressure control plate  21  is backward pushed (see the dotted shape  21 ′ in  FIG. 3 ) and the exhaust gas enters the noise elimination part  25 . The exhaust pressure control plate  21  prevents the temperature drop in the engine&#39;s combustion room occurring in the conventional muffler by screen the open shape of the exhaust gas passing channel from the atmosphere. The weight of the exhaust pressure control plate  21  is dependent on the amount of engine power. That is, in the small car having the small power engine, the light plate  21  is used, while in the bigger car having the stronger power engine, the heavier plate  21  is used.  
      The exhaust noise, especially high-frequency noise, of the gas entering the noise elimination part  25  is absorbed by the sound absorber  23  through the fine meshes of the mesh pipe  22 , thereby being eliminated. The mesh pipe  23  exhibits the much more effective sound elimination in that it increases the amount of exhaust sound entering the sound absorber  23  compared to the multi-punctured pipe of the conventional tuning muffler, and protects un-eliminated sound from discharging from the sound absorber  23 . In addition, it also increases the engine power compared to the conventional multi-punctured pipe. In the present invention, since the sound absorber  23  is formed by piling different materials having different sound absorbing properties, the sound elimination efficiency can be more increased comparing to the conventional art.  
       FIG. 8  shows another embodiment of the present invention. The difference from one in  FIG. 3  is that a second noise elimination part  25 ′ is connected to the noise elimination part  25 . The structure of the second noise elimination part  25 ′ is the same as the noise elimination part  25 . By adding an extra noise elimination part, the noise elimination efficiency can be increased, of the matter of course. Further, three or more noise elimination part may be connected, and between the noise elimination parts the exhaust pressure control part  20  explained in  FIG. 1  may be added. In addition, the manufacturer may provide a structure so that a user can easily assemble and disassemble the multiple noise elimination parts and exhaust pressure control parts. By doing so, users may obtain the muffler suiting their taste or fondness.  
       FIG. 9  shows still another embodiment of the present invention, in which the difference from one in  FIG. 8  is the order of the noise elimination part  25  and the exhaust pressure control part  20 . That is, the muffler is constructed by connecting a first noise elimination part  25  to the exhaust manifold, an exhaust pressure control part  20  to the first noise elimination part  25 , and again a second noise elimination part  25 ′ to the exhaust pressure control part  20 . The structure of the noise elimination part  25 ,  25 ′ and the exhaust pressure control part  20  are the same as those in  FIG. 1 . Similar to the case in  FIG. 8 , the muffler may be constructed by adding extra noise elimination parts and exhaust pressure control parts.  
       FIG. 10  shows yet another embodiment of the present invention, in which a third noise elimination part  25 ″ is connected to the second noise elimination part  25 ′ shown in  FIG. 8 . However, in this embodiment the first noise elimination part  25  is structured by the mesh pipe of the present invention, and the second and the third noise elimination part  25 ′,  25 ″ are structured by the conventional multi-punctured pipe. This embodiment in  FIG. 10  operates substantially the same as that in  FIG. 8 , and however a user can precisely tune the exhaust sound and output power according to the present embodiment. As above, those who skilled in the art may design a variety of combination of the inventive noise elimination parts and the conventional ones for their certain purposes.  
      By the way, in the exhaust pressure control part  20  shown in  FIG. 3 , the exhaust pressure control plate  21  may produce undesired clinking noise because it knocks against the casing during operation. To get rid of this noise, a tapered multi-punctured pipe  29  is substitutionally inserted in the mesh pipe  22 , as shown in  FIG. 11 . The figure of the tapered multi-punctured pipe  29  is depicted in  FIG. 12 . Since an entrance diameter of the tapered multi-punctured pipe  29  is greater than the exit diameter, the exhaust gas introduced to the entrance receives the more pressure than the untapered conventional pipe, during passing the exhaust gas passing channel. Therefore, the tapered multi-punctured pipe  29  performs operation similar to the exhaust pressure control plate  21 . That is, the tapered multi-punctured pipe  29  controls the pressure of the exiting exhaust gas, such that the engine room temperature is not decreased under the influence of the atmospheric temperature. According to the experiment, without the exhaust pressure control part  20 , the temperature of the engine room was not decreased. In the experiment, the length of the tapered multi-punctured pipe  29  was set by around ⅓ of the mesh pipe  22 . However, the length is not limited to that. It is preferable that the tapered multi-punctured pipe  29  is located at the endpoint of the engine, but this is not limited to the position.  
      While the invention has been shown and described with reference to certain embodiments to carry out this invention, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.