Patent Abstract:
A multi-chamber resonator box for a vehicle air intake system, wherein the resonator includes a Helmholtz, an expansion chamber, an annular, and a perforated style resonator to militate against the emission of noise energy caused by intake air.

Full Description:
FIELD OF THE INVENTION 
     The invention relates to a resonator and more particularly to a multi-chamber resonator box for a vehicle air intake system, the resonator including serially arranged Helmholtz, expansion chamber, annular, and perforated type resonators. 
     BACKGROUND OF THE INVENTION 
     In an internal combustion engine for a vehicle, it is desirable to design an air induction system in which sound energy generation is minimized. Sound energy is generated as fresh air is drawn into the engine. Vibration is caused by the intake air in the air feed line which creates undesirable intake noise. Resonators of various types such as a Helmholtz type, for example, have been employed to reduce engine intake noise. Such resonators typically include a single chamber for dissipating the intake noise. 
     It would be desirable to produce a multi-chamber air resonator system which militates against the emission of sound energy caused by the intake air and minimizes underhood space requirements while maintaining desired underhood appearance. 
     SUMMARY OF THE INVENTION 
     Consistent and consonant with the present invention, a multi-chamber air resonator system, which militates against the emission of sound energy caused by the intake air and minimizes underhood space requirements while maintaining desired underhood appearance, has surprisingly been discovered. 
     The multi-chamber resonator system comprises: 
     a duct having an inlet and an outlet; 
     a main body surrounding at least a portion of the duct; 
     at least two resonators of a different type disposed in the main body, the at least two resonators in communication with the duct to attenuate noise travelling through the duct. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above, as well as other objects, features, and advantages of the present invention will be understood from the detailed description of the preferred embodiments of the present invention with reference to the accompanying drawings, in which: 
     FIG. 1 is an exploded perspective view of a multi-chamber resonator incorporating the features of the present invention; and 
     FIG. 2 is a schematic perspective view of the multi-chamber resonator illustrated in FIG. 1 in an assembled state and including an automobile engine air cleaner attached thereto. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings, and particularly FIG. 1, there is shown generally at  10  a multi-chamber air resonator system incorporating the features of the invention. The air resonator system  10  includes a tray section  12 , an inner cover section  14 , a cover section  16 , and an outlet section  18 . 
     The tray section  12  is hollow and generally bell shaped with two open ends. In the embodiment shown, the tray section  12  is formed to include a smaller diameter air inlet  20 , an expanding section  22 , and a larger diameter main body  24 . The air inlet  20  is adapted to draw air from the atmosphere. The expanding section  22  connects the air inlet  20  and the main body  24 . A mounting lug  26  is disposed on the outer wall of the main body  24  for mounting the resonator system  10  as desired. 
     The inner cover section  14  is adapted to be inserted into the tray section  12 . In the embodiment shown, two types of resonators are included in the inner cover section  14 . A generally cylindrical hollow center tube  28  extends the length of the inner cover section  14 . A nose portion  30  of the tube  28  is adapted to be received in the air inlet  20  of the tray section  12 . An airtight fit is desired between the nose portion  30  of the tube  28  and the air inlet  20 , but is not critical to the operation of the resonator system  10 . 
     A radially outwardly extending annular plate  32  is disposed on the end of the tube  28  opposite the nose portion  30 . An array of radially outwardly extending hollow cylindrical extensions  34  are disposed on an outer wall of the tube  28 . In the embodiment shown, four extensions  34  are used. Additional or fewer extensions  34  can be used as desired. An array of apertures  36  are formed in the wall of the tube  28  and are aligned with the hollow interior of the extensions  34 . 
     A plurality of dividing walls  38  are disposed to separate each of the extensions  34  from one another and form a resonator chamber. Each chamber has one of the extensions  34  disposed therein. The walls  38  extend in a longitudinal direction with respect to the tube  28 . In the embodiment shown, the quantity of the walls  38  is equal to the quantity of the extensions  34 . Each of the walls  38  abut the plate  32 . An outer edge  40  of the walls  38  has a shape matching that of the inner surface of the main body  24  and the expanding section  22 . The walls  38  terminate adjacent the nose portion  30  of the tube  28  so as not to interfere with the insertion of the nose portion  30  into the air inlet  20 . The extensions  34 , the apertures  36 , and the walls  38  are arranged and sized as needed to form and tune each of the corresponding resonator chambers to the desired frequency for noise attenuation and/or improved sound quality. 
     A first annular ring  42  and a second annular ring  44  are disposed on the end of the tube  28  adjacent the nose portion  30 . The rings  42 ,  44  cooperate with the walls  38  to form small chambers therebetween. A first annular array of perforations  46  is formed in the outer wall of the tube  28  between the nose portion  30  and the first ring  42 . A second annular array of perforations  48  is formed in the outer wall of the tube  28  between the first ring  42  and the second ring  44 . In the embodiment shown, two rings  42 ,  44  and two arrays of perforations  46 ,  48  are shown. It is understood that more or fewer rings and arrays of perforations could be used without departing from the scope and spirit of the invention. 
     The cover section  16  includes a generally cylindrical hollow center tube  50 . A bell section  52  is formed around the tube  50 . The bell  52  has an annular lip  54  which is adapted to be joined with the end of the main body  24  of the tray section  12 . One end of the tube  50  of the cover section  16  is adapted to abut the end of the tube  28  of the inner cover section  14 . Although an air tight fit is desired between the tube  50  of the cover section  16  and the tube  28  of the inner cover section  14 , it is not critical to the operation of the resonator system  10 . An outlet tube  56  is formed at the end of the cover section  16  opposite the end of the tube  50  of the cover section  16  which abuts the tube  28  of the inner cover section  14 . The tube  50  and the bell  52  of the cover section  16  cooperate to form a resonator volume, which in the embodiment shown has an annular entry for the noise. 
     The outlet section  18  is a hollow conduit having an inlet end  58  and an outlet end  60 . The inlet end  58  is adapted to receive the outlet tube  56  of the cover section  16 . Although an air tight fit is desired between the inlet end  58  of the outlet section  18  and the outlet tube  56  of the cover section  16 , it is not critical to the operation of the resonator system  10 . The outlet end  60  is adapted to be connected to an engine mounted air cleaner  62 , as illustrated in FIG.  2 . FIG. 2 shows the resonator system  10  in an assembled condition. 
     In its assembled condition, the air inlet  20 , the tube  28 , the tube  50 , and the outlet section  18  cooperate to form a conduit for air to travel through. Additionally, upon assembly, a series of resonators are formed within the resonator system  10 . 
     In the embodiment shown, the first annular ring  42  cooperates with the inner surface of the expanding section  22 , and the outer wall of the tube  28  to form a first chamber therebetween. The first chamber communicates with the hollow portion of the tube  28  through the first perforations  46 , thereby forming a first high frequency resonator section  66 . Similarly, the second annular ring  44  cooperates with the first annular ring  42 , the expanding section  22 , and the outer wall of the tube  28  to form a second chamber therebetween. The second chamber communicates with the hollow portion of the tube  28  through the second perforations  48 , thereby forming a second high frequency resonator section  68 . Although two high frequency resonator sections are illustrated, fewer or more high frequency resonator sections may be used without departing from the scope and spirit of the invention. 
     Four Helmholtz type resonators are formed in the embodiment shown in the drawings. The plate  32  cooperates with two of the walls  38 , the inner surface of the main body  24  of the tray section  12 , and the outer wall of the tube  28  to form a first Helmholtz resonator chamber. The first Helmholtz resonator chamber communicates with the hollow portion of the tube  28  through one of the apertures  36 , thereby forming a Helmholtz resonator. Three other Helmholtz resonators are similarly formed and cooperate to form a Helmholtz resonator section  70 . Fewer or more Helmholtz resonator sections may be used without departing from the scope and spirit of the invention. 
     An annular entry type resonator  72  is formed in the cover section  16  for attenuating low frequency noise. The tube  50  extends from the tube  28  and a desired distance into the tube  56 . A clearance exists between the outer wall of the tube  50  and the inner wall of the tube  56 . The annular entry into the chamber of the annular resonator  72  is formed by the clearance between the outer wall of the tube  50  and the inner wall of the tube  56 . The noise enters the chamber of the annular resonator  72  through the clearance. 
     It is understood that other resonator types could be used such as an expansion chamber type, for example, in place of the above resonator types without departing from the scope and spirit of the invention. 
     In operation, air enters the resonator system  10  through the air inlet  20 , as indicated by the arrow  64 . The air travels through the conduit formed by the air inlet  20 , the tube  28 , the tube  50 , and the outlet section  18 , through the air cleaner  62 , and into an associated engine  74 . Noise generated by the engine  74  travels outward through the air cleaner  62 , the outlet section  18 , the tube  50 , the tube  28 , and exits through the tube  20  in a direction opposite to the air flow. The first high frequency resonator section  66 , the second high frequency resonator section  68 , the Helmholtz resonator section  70 , and the annular resonator  72  receive the noise pulses at various frequencies and reduce the amplitude of the noise pulses. By reducing the amplitude of the noise pulses, a desired sound quality is reached. 
     Since each resonator section has a separate chamber volume, individual noise pulse frequencies can be attenuated. Adjustments to or tuning of the individual resonator sections can be made by adjusting the volume of the chambers, the inside diameter of the apertures  36  or perforations  46 ,  48 , or the length of the extensions  34 . Tuning can also be accomplished by modifying the conduit formed by the tube  28 , the tube  50 , and the outlet  18 . The location of the walls  38  and the annular rings  42 ,  44  can be altered to change the volume of the chambers of the Helmholtz resonators and the high frequency resonators, respectively. By using the multi-chamber design with the different types of resonators, complex tuning can be accomplished to reach desired sound quality. Additionally, the multi-chamber design facilitates an efficient use of space under the hood of an automobile. 
     From the foregoing description, one ordinarily skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications to the invention to adapt it to various usages and conditions.

Technology Classification (CPC): 5