Abstract:
A variable intake system may include a single plenum that is connected to runners and that has a space formed therein, a first barrier that divides the space inside the plenum into a first space and a second space, a first variable valve that is mounted on the first barrier to connect or isolate the first space and the second space to/from each other, a variable pipe of which one side thereof is connected to the plenum and the other side is closed, a second barrier that divides the variable pipe into at least two spaces, and a second variable valve that is mounted on the second barrier to connect or isolate the at least two spaces to/from each other to improve intake efficiency.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    The present application claims priority to Korean Patent Application Number 10-2008-0109852 filed Nov. 6, 2008, the entire contents of which application 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 intake system, and more particularly to a variable intake system in which a variable pipe is formed in a plenum of an intake manifold to improve intake efficiency. 
         [0004]    2. Description of Related Art 
         [0005]    Generally, an intake manifold guides intake air to combustion chambers and uniformly distributes a mixture of air and fuel to a plurality of combustion chambers. 
         [0006]    The intake manifold includes a plurality of runners that are connected to intake ports and a plenum that is disposed to be connected to the runners, and efficiency of an engine is varied according to the capacity of the plenum. 
         [0007]    In order to improve the efficiency of the intake manifold a variable pipe is further formed on the plenum, however it is difficult to secure appropriate length and cross-section of the variable pipe according to the layout of the engine. 
         [0008]    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 
       [0009]    Various aspects of the present invention are directed to provide a variable intake system having advantages of variably improving intake efficiency and securing the length and the cross-section of a variable pipe according to the layout of an engine by changing the structure of the variable pipe. 
         [0010]    In an aspect of the present invention, the variable intake system may include a single plenum that is connected to runners and that has a space formed therein, a first barrier that divides the space inside the plenum into a first space and a second space, a first variable valve that is mounted on the first barrier to connect or isolate the first space and the second space to/from each other, a variable pipe of which one side thereof is connected to the plenum and the other side is closed, a second barrier that divides the variable pipe into at least two spaces, and a second variable valve that is mounted on the second barrier to connect or isolate the at least two spaces to/from each other. 
         [0011]    The first barrier and the second barrier may be connected to each other. 
         [0012]    The second variable valve may be disposed in an end portion that is a closed part of the variable pipe, the second barrier of the variable pipe is disposed in a length direction of the variable pipe, and the at least two spaces of the variable pipe are disposed in a vertical (or up/down) direction. 
         [0013]    The first variable valve or the second variable valve may be variably opened or closed according to engine rotation speed or the opening amount of a throttle valve. 
         [0014]    The runners may include at least a first runner that is connected to a first bank of an engine and at least a second runner that is connected to a second bank of the engine. 
         [0015]    In another aspect of the present invention, a control method of a variable intake system including a single plenum that is connected to runners and that has a space formed therein, a first barrier that divides the plenum into a first space and a second space, a first variable valve that is mounted on the first barrier to connect or isolate the first space and the second space to/from each other, a variable pipe of which one side thereof is connected to the plenum and the other side is closed, a second barrier that divides the variable pipe into at least two spaces, and a second variable valve that is mounted on the second barrier to connect or isolate the at least two spaces to/from each other, may include, detecting rotation speed of an engine, detecting an opening amount of a throttle valve, and controlling an opening amount of the second variable valve according to the rotation speed of the engine and/or the opening amount of the throttle valve. 
         [0016]    The control method of a variable intake system may further include controlling the opening amount of the first variable valve according to the rotation speed of the engine and/or the opening amount of the throttle valve. 
         [0017]    The control method of a variable intake system may further include closing the first variable valve and the second variable valve at a first predetermined engine speed and opening the first variable valve and the second variable valve at a second predetermined engine speed, wherein the first predetermined engine speed is lower than the second predetermined engine speed. 
         [0018]    The control method of a variable intake system may further include opening the first and second variable valves in a case in which the rotation speed of the engine is larger than or equal to a first predetermined value and the opening amount of the throttle valve is larger than or equal to a predetermined opening amount, closing the first variable valve and opening the second variable valve in a case in which the rotation speed of the engine is less than the first predetermined value and is larger than a second predetermined value, and closing the first and second variable valves in a case in which the rotation speed of the engine is less than the second predetermined value and is larger than or equal to a third predetermined value. 
         [0019]    The control method of a variable intake system may further include closing the first and second variable valves in a case in which the rotation speed of the engine is less than a third predetermined value. 
         [0020]    The control method of a variable intake system may further include comprising opening the first and second variable valves in a case in which the opening amount of the throttle valve is less than the predetermined opening amount. 
         [0021]    As stated above, in the variable intake system according to the present invention, the variable pipe efficiently absorbs a pressure wave generated in the plenum to improve intake efficiency. 
         [0022]    Further, the pressure wave inside the plenum is efficiently absorbed according to the closing state and the opening state of the variable valve that is mounted on the barrier. 
         [0023]    In addition, the variable pipe is divided into upper and lower portions and therefore it is possible to dispose the variable pipe in a narrow space. 
         [0024]    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 
         [0025]      FIG. 1  is a schematic diagram of an exemplary variable intake system according to the present invention. 
           [0026]      FIG. 2  is an external perspective view of an exemplary variable intake system according the present invention. 
           [0027]      FIG. 3  is an internal top plan view of an exemplary variable intake system according to the present invention. 
           [0028]      FIG. 4  is an internal side view of an exemplary variable intake system according to the present invention. 
           [0029]      FIG. 5  is a graph showing the performance of an exemplary engine that is equipped with an exemplary variable intake system according to the present invention. 
           [0030]      FIG. 6  is a schematic diagram showing constituent elements of an exemplary variable intake system according to the present invention. 
           [0031]      FIG. 7  is a control flowchart of an exemplary variable intake system according to the present invention. 
       
    
    
     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 schematic diagram of an exemplary variable intake system according to the present invention. 
         [0034]    Referring to  FIG. 1 , a variable intake system includes runners  112  that are connected to intake ports, a plenum  110  that is connected to the runners  112 , a zip tube  105  that supplies the plenum  110  with external air, and a throttle valve  100  that is mounted on the front portion of the zip tube  105 . 
         [0035]    Also, a variable pipe  125  is further disposed in one side of the plenum  110  in the variable intake system, and one end portion of the variable pipe  125  communicates with the plenum  110  and the other end portion has a closed structure. 
         [0036]    A barrier  115  is disposed in the zip tube  105 , the plenum  110 , and the variable pipe  125 , and the barrier divides the internal space thereof. Also, a first variable valve  120  and a second variable valve  130  are mounted on the barrier  115 . 
         [0037]    The first variable valve  120  is disposed inside the plenum and the second variable valve  130  is disposed inside the variable pipe  125 . In this case, the first and second variable valves  120  and  130  are respectively opened or closed to improve intake efficiency according to the RPM of the engine or the opening amount of the throttle valve  100 . 
         [0038]    In various embodiments of the present invention, the runners  112  includes first runners that are connected to a first bank of the engine and second runners that are connected to a second bank of the engine, and it is desirable that the above structure is applied to V-type engine. 
         [0039]      FIG. 2  is an external perspective view of an exemplary variable intake system according to the present invention. 
         [0040]    Referring to  FIG. 2 , the variable intake system includes the runners  112 , the plenum  110 , the zip tube  105 , the variable pipe  125 , and the second variable valve  130 . 
         [0041]    Six runners  112  are sequentially disposed in a cylinder arrangement direction, and the plenum  110  is extended in a direction that the runners  112  are disposed. 
         [0042]    The runners  112  are connected to one edge of the plenum  110 , and the zip tube  105  and the variable pipe  125  are connected to the other edge of the plenum  110 . 
         [0043]    As shown in  FIG. 2 , the plenum  110  is disposed in one (left) side of the upper portion of the engine, and therefore it is easy to design the layout of the engine. 
         [0044]      FIG. 3  is an internal top plan view of an exemplary variable intake system according to the present invention, and  FIG. 4  is an internal side view of an exemplary variable intake system according to the present invention. 
         [0045]    Referring to  FIG. 3  and  FIG. 4 , a first barrier  115   a  divides the inside space of the plenum  110  into upper and lower spaces, and a second barrier  115   b  divides the inside space of the variable pipe  125  into upper and lower spaces. The first and second barriers  115  are connected with each other in various embodiments of the present invention. 
         [0046]    Also, the first variable valve  120  is disposed in the first barrier  115   a  to be opened or closed, and the upper and lower spaces of the plenum  110  communicate with each other through the first variable valve  120 . 
         [0047]    Also, the second variable valve  130  is disposed on the second barrier  115   b,  and a valve vane  300  that is connected to the second variable valve  130  is operated by the second variable valve  130 . Accordingly, the spaces that are divided in an upper/lower direction of the variable pipe  125  are opened or closed by the valve vane  300 . 
         [0048]    Referring to  FIG. 4 , the plenum  110  includes a right plenum  110   a  that is formed in an upper portion and a left plenum  110   b  that is formed in a lower portion thereof, and the left and right plenums  110   a  and  110   b  are connected or intercepted by the first variable valve  120 . 
         [0049]    The upper space of the variable pipe  125  is connected to the right plenum  110   a  and the lower space is connected to left plenum  110   b.  Also, the second barrier  115   b  that is mounted in the variable pipe  125  is formed in a length direction of the variable pipe  125 , and the second variable valve  130  is formed in an end portion of the second barrier  115   b.    
         [0050]    Referring to  FIG. 4 , the variable pipe  125  absorbs a pressure wave of the plenum that is generated during an intake stroke to improve intake efficiency. 
         [0051]      FIG. 5  is a graph showing the performance of an engine that is equipped with an exemplary variable intake system according to the present invention. 
         [0052]    Referring to  FIG. 5 , the horizontal axis designates RPM of the engine and the vertical axis designates torque that is output by the engine. Also, a first line  500 , a second line  505 , a third line  510 , and a fourth line  515  respectively shows the relationship of the torque and the RPM according to the operating condition of the engine. 
         [0053]    The first line  500  shows the torque of the engine in a state in which both the first and second variable valves  120  and  130  are closed, and the second line  505  shows the torque of the engine in a state in which the first variable valve  120  is closed and the second variable valve  130  is opened. 
         [0054]    The third line  510  shows the state in which the first and second variable valves  120  and  130  are opened. Further, the fourth line  515  shows the state in which the first and second variable valves  120  and  130  are variably controlled according to the RPM of the engine. 
         [0055]    As shown in  FIG. 5 , when the first and second variable valves  120  and  130  are variably controlled according to the RPM of the engine, the torque of the engine is raised overall. 
         [0056]      FIG. 6  is a schematic diagram showing constituent elements of an exemplary variable intake system according to the present invention. 
         [0057]    Referring to  FIG. 6 , the variable intake system includes a battery  600 , a PCM  610 , first and second solenoid valves  612  and  614 , first and second actuators  620  and  622 , the first and second variable valves  120  and  130 , a vacuum tank  630 , and a surge tank  640 . 
         [0058]    The PCM  610  receives electric power from the battery  600  and supplies operating signals to the first and second solenoid valves  612  and  614 , and the first and second solenoid valves  612  and  614  use air pressure of the vacuum tank  630  and the surge tank  640  to control the first and second variable valves  120  and  130  through the first and second actuators  620  and  622 . 
         [0059]      FIG. 7  is a control flowchart of an exemplary variable intake system according to the present invention. 
         [0060]    Referring to  FIG. 7 , an electronic control unit (ECU) detects the opening amount of the throttle valve  100  and the RPM of the engine in a starting step S 70 . 
         [0061]    In a first step S 71 , it is determined whether the opening amount of the throttle valve  100  is higher than 25%. When the opening amount of the throttle valve  100  is higher than 25%, it is determined whether the RPM of the engine is higher than a predetermined value of 5000 in a second step S 72 . 
         [0062]    When the RPM of the engine is higher than the predetermined value of 5000 in the second step S 72 , the first and second variable valves  120  and  130  are opened in a third step S 73 . 
         [0063]    In a case in which the opening amount of the throttle valve  100  is less than 25% in the first step S 71 , both the first and second variable valves  120  and  130  are opened in the fourth step S 74 . Also, when the RPM of the engine is less than 5000 in the second step S 72 , a fifth step S 75  is executed. 
         [0064]    It is determined whether the engine RPM is higher than 4000 in the fifth step S 75 . If the engine RPM is higher than 4000, a sixth step S 76  is executed. The first variable valve  120  is closed and the second variable valve  130  is opened in the sixth step S 76 . 
         [0065]    If the engine RPM is less than 4000 in the fifth step S 75 , the seventh step S 77  is brought to effect. It is determined whether the engine RPM is higher than a predetermined value of 1400 in the seventh step S 77 . If the engine RPM is higher than 1400, the eighth step S 78  is carried out. The first and second variable valves  120  and  130  are both closed in the eighth step S 78 . 
         [0066]    If the engine RPM is less than 1400 in the seventh step S 77 , the fourth step S 74  can be carried out so as to improve the idling stability of the engine according to various embodiments of the present invention. 
         [0067]    The resonance frequency of the intake is varied to improve the performance of the engine by opening or closing the first and second variable valves that are respectively mounted on the plenum and the variable pipe in various embodiments of the present invention. Particularly, the variable pipe is divided into upper and lower portions such that the installation thereof becomes easier in a narrow space. 
         [0068]    For convenience in explanation and accurate definition in the appended claims, the terms “upper” and “lower” are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures. 
         [0069]    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.