Abstract:
A variable muffler may include a housing, a plurality of chambers formed by partitions in the housing, an inlet pipe connected to at least a chamber for flowing exhaust gas into the housing, an outlet pipe connected to at least a chamber for discharging the exhaust gas having flowed into the housing to the exterior, an inner pipe for directly communicating between at least two chambers in the housing so that the exhaust gas of the inlet pipe is communicated to the outlet pipe therethrough, and a variable valve that is disposed downstream of the inner pipe and of which opening amount is continuously adjusted according to pressure of exhaust gas passing through the inner pipe.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    The present application claims priority to Korean Patent Application No. 10-2009-0118713 filed in the Korean Intellectual Property Office on Dec. 2, 2009, the entire contents of which is incorporated herein for all purposes by this reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a variable muffler, more particularly to a variable muffler including a valve capable of controlling a flow rate of exhaust gas in two stages. 
         [0004]    2. Description of Related Art 
         [0005]    Generally, as to gasoline engines applied to vehicles, silence is required at a normal engine speed range, for example at a range of 750 rpm to 2500-3000 rpm, and high output power rather than the silence is required at a high speed range, for example at more than 3000 rpm. 
         [0006]    The engine noise is generated by exhaust noise from the engine. To reduce the noise and to generate high output power, various mufflers have been disclosed. 
         [0007]    To satisfy the requirement, as conventional fashion, a muffler including a variable valve that is mounted inside a muffler and reduces exhaust gas pressure has been disclosed. 
         [0008]    The muffler is mounted such that a variable valve disposed at an outlet of exhaust gas of a communicated pipe in the muffler is supported by an elastic member. 
         [0009]    Herein, at a normal speed of the engine, because exhaust gas pressure is low, the variable valve is in a state of being closed by elastic force exerted on the variable valve toward a communicating pipe of the elastic member that is higher than the exhaust gas pressure, and exhaust discharged from the muffler outwardly passes through a passage having exhaust gas resistance and thereby the exhaust noise is reduced. 
         [0010]    Meanwhile, when the engine reaches 3000 rpm, in a high speed range, the exhaust gas pressure is increased and the exhaust gas pressure is higher than the supporting force of the elastic member, and thereby the variable valve is opened. 
         [0011]    However, the conventional fashion for opening or closing a variable valve simply according to exhaust gas pressure has a limit in which flow noise at a high speed is increased, torque at a low speed is decreased, exhaust gas pressure at a high speed is decreased, and the like. 
         [0012]    The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art. 
       BRIEF SUMMARY OF THE INVENTION 
       [0013]    Various aspects of the present invention are directed to provide a variable muffler having advantages of precisely controlling a flow rate of exhaust gas in two stages in order to reduce exhaust gas noise. 
         [0014]    In an aspect of the present invention, the variable muffler may include a housing, a plurality of chambers formed by partitions in the housing, an inlet pipe connected to at least a chamber for flowing exhaust gas into the housing, an outlet pipe connected to at least a chamber for discharging the exhaust gas having flowed into the housing to the exterior, an inner pipe for directly communicating between at least two chambers in the housing so that the exhaust gas of the inlet pipe is communicated to the outlet pipe therethrough, and a variable valve that is disposed downstream of the inner pipe and of which opening amount is continuously adjusted according to pressure of exhaust gas passing through the inner pipe. 
         [0015]    The variable valve may include a valve body connected to the inner pipe and a plurality of valves hingedly and elastically connected each other sequentially, wherein a first valves of the valves is hingedly and elastically connected to the valve body. 
         [0016]    The variable valve may include the valve body connected to the inner pipe, a first hinge portion disposed to the valve body, the first valve hingedly connected to the first hinge portion, a second hinge portion disposed to the first valve, and a second valve hingedly connected to the second hinge portion. 
         [0017]    The variable valve may further include a first elastic member which is disposed to the first hinge portion and elastically biases the first valve in a direction, and a second elastic member which is disposed to the second hinge portion and elastically biases the second valve in the direction, wherein an elastic coefficient of the first elastic member is less than an elastic coefficient of the second elastic member. 
         [0018]    The partition may include first and second partitions disposed within the housing, and the first and second partitions and the housing form first, second, and third chambers, wherein the inlet pipe is communicated with the third chamber through the first chamber, the first partition and the second partition. 
         [0019]    A first partition penetration hole may be formed to the first partition for communicating the first chamber with the second chamber formed by the first and second partitions, wherein a penetration hole is formed to the outlet pipe for communicating with the second chamber, wherein the second chamber includes a sound absorbent therewithin, and wherein the sound absorbent is made of glass wool material. 
         [0020]    The outlet pipe may be formed with a “U” shape, wherein the outlet pipe penetrates the first, second, and third chambers at least once, and wherein the outlet pipe penetrates the first chamber, the second chamber, the third chamber, the second chamber, the first chamber, the second chamber and the third chamber sequentially. 
         [0021]    The inner pipe may be disposed between the first chamber and the third chamber for communicating therebetween. 
         [0022]    According to the variable muffler of the exemplary embodiment of the present invention, the muffler may control a flow rate of exhaust gas in multiple stages according to engine operation condition, so that exhaust noise may be reduced. 
         [0023]    The methods and apparatuses of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description of the Invention, which together serve to explain certain principles of the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]      FIG. 1  is a top plan view of a variable muffler according to an exemplary embodiment of the present invention. 
           [0025]      FIG. 2  and  FIG. 3  is a perspective view of the variable muffler according to the exemplary embodiment of the present invention. 
           [0026]      FIG. 4  is a top plan view of the variable muffler according to an exemplary embodiment of the present invention. 
           [0027]      FIG. 5  shows an operating state of the variable muffler at a low speed range according to the exemplary embodiment of the present invention. 
           [0028]      FIG. 6  shows an operating state of the variable muffler at a middle speed range according to the exemplary embodiment of the present invention. 
           [0029]      FIG. 7  shows an operating state of the variable muffler at a high speed range according to the exemplary embodiment of the present invention. 
       
    
    
       [0030]    It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various features illustrative of the basic principles of the invention. The specific design features of the present invention as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particular intended application and use environment. 
         [0031]    In the figures, reference numbers refer to the same or equivalent parts of the present invention throughout the several figures of the drawing. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0032]    Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims. 
         [0033]      FIG. 1  is a top plan view of a variable muffler according to an exemplary embodiment of the present invention and  FIG. 2  and  FIG. 3  is a perspective view of the variable muffler according to the exemplary embodiment of the present invention. 
         [0034]      FIG. 4  is a top plan view of the variable muffler according to an exemplary embodiment of the present invention and  FIG. 5  shows an operating state of the variable muffler at a low speed range according to the exemplary embodiment of the present invention. 
         [0035]      FIG. 6  shows an operating state of the variable muffler at a middle speed range according to the exemplary embodiment of the present invention and  FIG. 7  shows an operating state of the variable muffler at a high speed range according to the exemplary embodiment of the present invention. 
         [0036]    Referring to  FIG. 1  to  FIG. 3 , a variable muffler according to an exemplary embodiment of the present invention includes a housing  100 , an inlet pipe  110 , an outlet pipe  120 , an inner pipe  130  disposed within the housing  100 . 
         [0037]    The inside of the housing  100  is divided into a plural of chambers  101 ,  102 , and  103  by partitions  140  including a plurality of holes therein. 
         [0038]    One end of the inlet pipe  110  is outwardly protruded from the housing  100 , and the other end thereof is formed so that exhaust gas flows into the housing  100 . 
         [0039]    Further, the inlet pipe  110  is installed in a state of being inserted into the housing  100  so that exhaust gas flowing into the housing  100  is exhausted toward the rear side of the housing  100 . 
         [0040]    The partition  140  includes a first and second partition  141  and  142  disposed within the housing  100 , and the first and second partition  141  and  142  and the housing  100  form a first, second, and third chamber  101 ,  102 , and  103 . 
         [0041]    The inlet pipe  110  communicates with the third chamber  103  through the first chamber  101 , the first partition  141  and the second partition  142 . 
         [0042]    A penetration hole  123  is formed to the outlet pipe  120  for communicating with the second chamber  102 . 
         [0043]    The penetration hole  123  may be a plurality of holes formed to an exterior circumference of the outlet pipe  120  to reduce noise. 
         [0044]    The second chamber  102  is filled with a sound absorbent  240 . 
         [0045]    The sound absorbent  240  may be made of glass wool so as to reduce flow noise generated when exhaust gas passes through the second chamber  102 . 
         [0046]    The inner pipe  130  is disposed to communicate the first chamber  101  with the third chamber  103 . 
         [0047]    A first partition penetration hole  143  is formed to the first partition  141  to communicate the first chamber  101  with the second chamber  102 . 
         [0048]    The outlet pipe  120  is formed with a “U” shape. 
         [0049]    The outlet pipe  120  may penetrate the first, second, and third chamber  101 ,  102 , and  103  at least once. 
         [0050]    The outlet pipe  120  may penetrate the first chamber  101 , the second chamber  102 , the third chamber  103 , the second chamber  102 , the first chamber  101 , the second chamber  102  and the third chamber  103  sequentially. 
         [0051]    A variable valve  200  is disposed to a downstream side of the inner pipe  130 , which is the inner pipe exit  132 , for controlling stream of exhaust gas. 
         [0052]    The variable valve  200 , as shown in  FIG. 4  to in  FIG. 7  includes a valve body  201  connected to the inner pipe exit  132 , a first hinge portion  210  disposed to the valve body  201 , a first valve  231  hingedly connected to the first hinge portion  210 , a second hinge portion  220  disposed to the first valve  231  and a second valve  232  hingedly connected to the second hinge portion  220 . 
         [0053]    The variable valve  200  further may include a first elastic member  211  which is disposed to the first hinge portion  210  and elastically supports the first valve  231  and a second elastic member  222  which is disposed to the second hinge portion  220  and elastically supports the second valve  232 . 
         [0054]    An elastic coefficient of the first elastic member  211  is less than an elastic coefficient of the second elastic member  222 . 
         [0055]    That is, displacement of the first valve  231  elastically supported by the first elastic member  211  is greater than that of the second valve  232  supported by the second elastic member  222 . 
         [0056]    Herein, the first and second controlling valves  231  and  232  of the variable valve  200  has an area that is capable of opening or closing one end of the inner pipe  130 , and it is formed with a circular plate shape. 
         [0057]    In this way, an operating state of the variable valve  200  according to engine speed is automatically controlled, so an amount of exhaust gas passing through the chambers  101 ,  102 , and  103  of the housing  100  is controlled. An operating state of the variable valve  200  will hereinafter be described according to an operating state of a low speed, a middle speed, and a high speed. 
         [0058]    In the case of a low speed, the variable valve  200  is slightly opened for the exhaust to be leaked out, so that the exhaust gas passing through the inlet pipe  110  flows into the first chamber  101  through the third chamber  103 , an inner pipe entrance  131 , the inner pipe  130  and the variable valve  200  and exits through the outlet pipe entrance  121 . 
         [0059]    At the same time, partial exhaust gas passes through the penetration hole  123 . 
         [0060]    The sound absorbent  240  filled within the second chamber  102  may reduce flow noise. 
         [0061]    The partial exhaust gas flows into the first chamber  101  through the first partition penetration hole  143  and then exits through the outlet pipe entrance  121  and the outlet pipe  120 . 
         [0062]    In this case, pressure of the exhaust gas passing through the inlet pipe  110  is relatively low, so that the variable valve  200 , as shown in  FIG. 5 , is almost closed (slightly opened). 
         [0063]    That is, the variable valve  200  is almost closed due to elastic force of the first elastic member  211  elastically supporting the first valve  231 . 
         [0064]    In the case of a middle speed, the first valve  231  is opened by pressure exerted on the inside of the inlet pipe  110 , inlet pipe exit  112 , the third chamber  103  and the inner pipe  130  against elastic force of the first elastic member  211 . 
         [0065]    That is, an angle θ 1  defined by the first valve  231  is maintained the same as an angle θ 2  defined by the second valve  232 . 
         [0066]    Therefore, a portion of exhaust gas flowing into the second chamber  102  flows into the first chamber  101  through the first partition penetration hole  143 , and the remaining portion flows into the first chamber  103  through the variable valve  200 . 
         [0067]    The exhaust gas is then discharged out of the housing  100  through the outlet pipe entrance  121 . 
         [0068]    In the case of a high speed, the first valve  231  and the second valve  232  are opened by pressure exerted on the inside of the inlet pipe  110 , inlet pipe exit  112 , the third chamber  103  and the inner pipe  130  against elastic force of the first elastic member  211  and the second valve  232 . 
         [0069]    That is, an angle θ 2  defined by the second valve  232  is higher than an angle θ 1  defined by the first valve  231 . 
         [0070]    Particularly, in the case of the high speed the first valve  231  and the second valve  232  are opened simultaneously, exhaust gas flows out more smoothly than in the case of the low speed or in the case of the middle speed, so that engine output may be improved. 
         [0071]    Also, resistance generated in the high speed may be suppressed, so that exhaust gas noise may be reduced. 
         [0072]    The outlet pipe  120  is relatively formed at length, so that low frequency noise may be reduced effectively. 
         [0073]    For convenience in explanation and accurate definition in the appended claims, the terms “upper”, “lower”, “inner” and “outer” are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures. 
         [0074]    The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents.