Patent Publication Number: US-2006005798-A1

Title: Variable intake system of a vehicle

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
      This application claims priority of Korean Application No. 10-2004-0052420, filed Jul. 6, 2004, the disclosure of which is incorporated herein by reference.  
     FIELD OF THE INVENTION  
      Generally, the present invention relates to an engine for a vehicle. More particularly, the present invention relates to a variable intake system of a vehicle.  
     BACKGROUND OF THE INVENTION  
      There are various kinds of engines for a vehicle. Among them, an engine with a variable intake system varies the effective length of runners of the intake manifold according to vehicle driving conditions. As is generally known, such a variable intake system generally includes a throttle body, a plenum connected with the throttle body, an intake manifold having a plurality of runners receiving an air from the plenum, a passing part disposed on a predetermined portion of the intake manifold, an opening/closing part for opening and closing the passing part according to the vehicle driving condition (e.g., vehicle travel speed, etc.), and a motor driving the opening/closing part.  
      In order to reduce the weight of an engine, attempts have been made to change the materials used in variable intake systems to plastic materials. However, if the material of the variable intake system is changed to a plastic material, it has been experimentally found that noise increases. Such a noise increase phenomenon may occus because the flow rate suddenly increases due to a decrease of a friction loss when the air passes through the throttle body. Subsequently, such noise is also generated while the air passes through the runners of the intake manifold. In addition, such an intake noise may also be generated by a rotation of a crankshaft.  
      The information disclosed in this Background of the Invention section is only for enhancement of understanding of the background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art that is already known in this country to a person of ordinary skill in the art.  
     SUMMARY OF THE INVENTION  
      Embodiments of the present invention provide a variable intake system of a vehicle having non-limiting advantages of reducing weight and cost while effectively decreasing noise of the engine.  
      An exemplary variable intake system of a vehicle according to an embodiment of the present invention includes an intake manifold having a runner, an opening/closing part for varying the runner length, an actuator for driving the opening/closing part, and a vacuum part forming a vacuum chamber for driving the actuator. The vacuum part may be disposed on an upper portion of the intake manifold such that noise is decreased.  
      In a further embodiment according to the present invention, the vacuum part includes a body disposed on the upper portion of the intake manifold and having an opening portion at any one surface thereof, and a cover disposed on the opening portion of the body.  
      In another further embodiment according to the present invention, the body is monolithically formed with an upper surface of the intake manifold.  
      In another further embodiment according to the present invention, a sound-absorbing material layer is disposed on at least one surface of the cover.  
      In another further embodiment according to the present invention, the opening portion is formed at the upper portion of the body; and the sound-absorbing material layer is disposed on a lower surface of the cover. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The accompanying drawings illustrate exemplary embodiments of the present invention, and, together with the description, serve to explain the principles of the present invention, wherein:  
       FIG. 1  is a cutaway view in perspective of a variable intake system of a vehicle according to an embodiment of the present invention;  
       FIG. 2  is a block diagram of a driving unit for driving an opening/closing part in a variable intake system of a vehicle according to an embodiment of the present invention;  
       FIG. 3  is an exploded perspective view showing a variable intake system of a vehicle according to an embodiment of the present invention;  
       FIG. 4  is an enlarged view of part “A” in  FIG. 3 ; and  
       FIG. 5  is another perspective view showing a variable intake system of a vehicle according to an embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS  
      An embodiment of the present invention will hereinafter be described in detail with reference to the accompanying drawings.  
      In the following description, principal components of a variable intake system of a vehicle according to an embodiment of the present invention will firstly be described, and after this, means for decreasing noise of an engine according to embodiments of the invention will be described.  
      As shown in  FIG. 1 , a variable intake system of a vehicle according to an embodiment of the present invention includes a plenum  100  for receiving an external air, and an intake manifold  200  having at least one runner  210  for guiding the air from the plenum  100  into a cylinder. Also included is a connecting passage  120  formed at an end of the intake manifold  200  so as to be connected with the plenum  100 .  
      The variable intake system of a vehicle according to an embodiment of the present invention further includes a first connecting part  310 , and a second part  320 . The first connecting part  310  is provided to an upper portion of the plenum  100  and connects the plenum  100  and the intake manifold  200 . The second connecting part  320  is provided to a lower portion of the plenum  100  and connects the plenum  100  and the intake manifold  200 .  
      Furthermore, the first connecting part  310  is provided with a first guide passage  311  and a first opening/closing part  330 , and the second connecting part  320  is provided with a second guide passage  321  and a second opening/closing part  340 . The first and the second opening/closing parts  330  and  340  are driven by a driving unit utilizing a vacuum as follows.  
      As shown in  FIG. 2 , the driving unit includes a vacuum part  400  and an actuator  500 . The vacuum part  400  is connected to the plenum (see “ 100 ” in  FIG. 1 ), and forms a vacuum chamber that is changed between a vacuum state and a standard state according to a negative pressure of the plenum  100 . The actuator  500  is connected with the vacuum part  400 , and has a diaphragm disposed inside thereof. Accordingly the diaphragm is expanded or contracted according to the pressure state of the vacuum chamber, and the opening/closing part is driven according to the expansion/contraction of the diaphragm. Such a driving unit has an advantage that production cost may be lower than in a conventional scheme using a motor operated by electric power.  
      Operation of the variable intake system of a vehicle according to the embodiment of the present invention will hereinafter be described in detail with reference to  FIGS. 1 and 2 .  
      Firstly, when a vehicle is running at a high speed, the second opening/closing part  340  is rotated by the actuator  500 , and it closes the second guide passage  321  of the second connecting part  320 .  
      At that same time, the first opening/closing part  330  is rotated by the actuator  500 , and it widely opens the first guide passage  311  of the first connecting part  310 .  
      Accordingly, the air in the plenum  100  flows into the intake manifold  200  through the first guide passage  311  of the connecting part  310 . Therefore, the length of the runner  210  becomes effectively shortened. In the intake manifold  200 , the air that has passed through the guide passage  311  is mixed with the air that has passed through the connecting passage  120 .  
      On the other hand, when the vehicle is running at low speed, the second passage  321  of the second connecting part  320  is opened and the first passage  311  of the first connecting part  310  is closed. Therefore, the length of the runner  210  becomes effectively lengthened.  
      A means for decreasing a noise in the variable intake system of a vehicle according to the embodiment of the present invention will hereinafter be described in detail.  
      Firstly, noise emitted from an engine can be decreased, since a variable intake system of a vehicle according to an embodiment of the present invention employs the driving unit utilizing a vacuum instead of the conventional motor utilizing an electric power.  
      For example, as shown in FIGS.  3  to  5 , a means for decreasing such noise can be realized by disposing the vacuum part  400  on an upper portion of the intake manifold  200  intensively emitting a noise in the engine. According to a general arrangement of an engine in an engine compartment, an upper surface of the intake manifold  200  emits more noise than any other surface thereof. The upper surface of the intake manifold  200  is where an engine cover (not shown) for decreasing noise is generally disposed. Therefore, it is preferable that the vacuum part  400  is disposed on the upper portion of the intake manifold  200  so as to absorb the noise of the engine.  
      Noise emitted from side surfaces of the engine may be decreased by neighboring members located to the side surfaces thereof. However, noise emitted from the upper portion of the intake manifold  200  is not decreased since the upper portion usually does not have any neighboring members. Accordingly, it is preferable that the vacuum part  400  be disposed on the upper portion of the intake manifold  200 .  
      In addition, since the vacuum part  400  is disposed on the upper surface of the intake manifold  200 , a conventional engine cover is not required. Accordingly, a cost can be decreased. Adopting such a driving unit does not cause extra cost since the driving unit including the vacuum part  400  and the actuator  500  is used to replace the conventional motor.  
      It is preferable that the vacuum part  400  includes a body disposed on the upper surface of the intake manifold  200 , having an opening portion  411  at any one surface thereof, and a cover  420  disposed on the opening portion  411  of the body  410 . It also may be preferable that the body  410  be monolithically formed with the upper surface of the intake manifold  200 . Particularly, if the intake manifold  200  is formed of a resin, the body  410  and the intake manifold  200  may be formed as one body by an injection molding process.  
      Accordingly, a gap may be eliminated from between the upper surface of the intake manifold  200  and a lower surface of the vacuum part  400 , and therefore, noise emitted from the upper surface of the intake manifold  200  does not leak and is reduced by the vacuum chamber. In addition, manufacturing cost can be further reduced since the body  410  and the intake manifold  200  are formed by injection molding at the same time. A sound-absorbing material layer (see “ 421 ” in  FIG. 4 ) may be disposed on at least one surface of the cover  420 .  
      Accordingly, noise firstly decreased through the vacuum chamber of the vacuum part  400  can be further decreased by the sound-absorbing material layer  421 . Particularly, it is more preferable that the opening portion  411  is formed at the upper portion of the body  410 , and the sound-absorbing material layer  421  is disposed on a lower surface of the cover  420 . By such a location of the sound-absorbing layer  421 , the noise can be additionally decreased by the sound-absorbing material layer  421  before transmitting to the cover  420 .  
      A noise decreasing process in the variable intake system of a vehicle according to the embodiment of the present invention will hereinafter be described in detail.  
      Firstly, most of the noise generated in the engine is emitted from the upper surface of the intake manifold  200 .  
      The noise is firstly decreased through a vacuum layer of the vacuum chamber having a different air density. More specifically, a propagation direction of the noise through the vacuum layer is changed due to the density difference, and accordingly a transmittance of the noise is decreased.  
      After this, the noise passing through the vacuum layer is additionally decreased by the sound-absorbing material layer  421 .  
      As has been explained above, the variable intake system of a vehicle according to an embodiment of the present invention has several advantages. For example, since a driving unit using a vacuum is employed, cost can be reduced in comparison with a scheme that utilizes a conventional motor operated electric power. In addition, since the driving unit using the vacuum is also a means for decreasing noise, noise emitted from the engine can be considerably decreased without causing an increase of manufacturing cost.  
      While this invention has been described in connection with what is presently considered to be the most practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.