Air intake arrangement for internal combustion engine

Abstract

An air intake arrangement for an internal combustion engine comprising: a main air intake conduit leading to a gas intake valve ( 241 ) for respective engine cylinders ( 206 ) and including a main air intake passage ( 202 ), a main collector chamber ( 204 ) and independent branching air intake passages ( 205 ) for the respective engine cylinders ( 206 ) connected in series; a throttle valve ( 203 ) disposed in the main intake air passage ( 202 ) for controlling the flow rate of air passing therethrough; an auxiliary air intake passage ( 210 ) bypassing the main air intake conduit, wherein an inlet port of the auxiliary air intake passage ( 210 ) opens into the main air intake passage ( 202 ) at the upstream of the throttle valve ( 203 ), and an outlet port ( 213 ) of the auxiliary air intake passage ( 210 ) opens into the respective independent branching air intake passage ( 205 ) near the gas intake valve ( 241 ) for the respective engine cylinders ( 206 ) in such a manner that gas blown-out from the auxiliary air intake passage ( 210 ) induces a gas swirl in the respective engine cylinders ( 206 ); an intake air control valve ( 211 ) disposed in the auxiliary air intake passage ( 210 ) for controlling the flow rate of air passing therethrough; and a control unit ( 222 ) which determined determines an operating condition of the internal combustion engine and controls an opening degree of the intake air control valve ( 211 ) based on the determined engine operating condition.

We claim:  
     
       1. An air intake arrangement for an internal combustion engine comprising: 
       a main air intake conduit leading to a gas intake valve ( 241 ,  306 )  for respective engine cylinders ( 206 ,  244 ,  307 ,  150 )  and including a main air intake passage ( 202 ) , a main collector ( 204 ,  104 ,  304 ,  319 )  chamber and independent branching air intake passages ( 205 ,  305 ,  105 )  for the respective engine cylinders ( 206 ,  244 ,  307 ,  150 )  connected in series;  
       a throttle valve ( 203 ,  314 ,  103 )  disposed in the main intake air passage ( 202 )  for controlling the flow rate of air passing therethrough  
       an auxiliary air intake passage ( 210 ,  308 ,  113 )  bypassing said main air intake conduit, wherein an inlet port of said auxiliary air intake passage ( 210 ,  308 ,  113 )  opens into the main air intake passage ( 202 )  at the upstream of said throttle valve ( 203 ,  314 ,  103 ) , and an outlet port ( 213 )  of said auxiliary air intake passage ( 210 ,  308 ,  113 )  opens into the respective independent branching air intake passages ( 205 ,  305 ,  105 )  near the gas intake valve ( 241 ,  306 )  for the respective engine cylinders ( 206 ,  244 ,  307 ,  150 )  in such a manner that gas blown-out from said auxiliary air intake passage ( 210 ,  308 ,  113 )  induces a gas swirl in the respective engine cylinders ( 206 ,  244 ,  307 ,  150 ) ;  
       an intake air control valve ( 211 ,  313 ,  109 )  disposed in said auxiliary air intake passage ( 210 ,  308 ,  113 )  for controlling the flow rate of air passing therethrough;  
       an EGR gas passage ( 214 )  merged into said auxiliary air intake passage ( 210 )  at the downstream of said intake air control valve ( 211 ) ;  
       an EGR gas control valve ( 212 )  disposed in said EGR gas passage ( 214 )  for controlling the flow rate of EGR gas passing therethrough; and  
       a control unit ( 222 )  which determined  determines an operating condition of the internal combustion engine and controls opening degrees of said intake air control valve ( 211 )  and said EGR gas control valve ( 212 )  based on the determined engine operating condition.  
     
     
       2. An air intake arrangement for an internal combustion engine according to claim  1 , wherein said auxiliary air intake passage ( 210 )  is constituted by a first auxiliary air intake passage bypassing said throttle valve ( 203 ) , and a second auxiliary air intake passage ( 210 )  bypassing said main air intake conduit in such a manner that an inlet port of said second auxiliary air intake passage ( 210 )  opens into the main air intake passage at the downstream of said throttle valve ( 203 )  and an outlet port of said auxiliary air intake passage ( 210 )  opens into the respective independent branching air intake passages ( 205 )  near the gas intake valve ( 241 )  for the respective engine cylinders ( 206 ,  244 )  and further comprises a further throttle valve ( 251 )  disposed in the main air intake passage at the downstream of the inlet port of said second auxiliary air intake passage ( 210 )  for controlling flow rate of air passing through both said main air intake conduit and said auxiliary air intake passage ( 210 ) (FIG.  11 ) . 
     
     
       3. An air intake arrangement for an internal combustion engine according to claim  1 , wherein said auxiliary air intake passage ( 210 )  further comprises a throttle nozzle ( 254 )  at the outlet port ( 213 )  of said auxiliary air intake passage ( 210 )  for further controlling the flow rate of gas passing therethrough (FIG.  13 ) . 
     
     
       4. An air intake arrangement for an internal combustion engine according to claim  1 , wherein said auxiliary air intake passage ( 308 )  further comprises an auxiliary collector cheer ( 318 )  disposed downstream said intake air control valve ( 313 ) (FIG.  17 ) . 
     
     
       5. An air intake arrangement for an internal combustion engine according to claim  1 , wherein the outlet port ( 213 )  of said auxiliary gas intake passage ( 210 )  is positioned eccentrically with respect to said respective independent branching air intake passages ( 205 ) (FIG.  7  through FIG.  10 ) . 
     
     
       6. An air intake arrangement for an internal combustion engine according to claim  1 , wherein said auxiliary gas intake passage ( 210 )  is provided with a plurality of outlet ports ( 213 )  for said respective independent branching air intake passages ( 205 ) (FIG.  10 ) . 
     
     
       7. An air intake arrangement for an internal combustion engine according to claim  1 , wherein said auxiliary air intake passage ( 210 ,  308 )  further comprises a further auxiliary air intake passage bypassing said intake air control valve and a further intake air control valve disposed in said further auxiliary air intake passage (FIG. 12, FIG.  16 (a)) . 
     
     
       8. An air intake arrangement for an internal combustion engine according to claim  3 , wherein both said throttle valve ( 314 )  and said intake air control valve ( 313 )  are mechanically coupled to an acceleration pedal and are controlled in synchronism with a predetermined time lag (FIG.  16 (a) FIG.  16 (b)) . 
     
     
       9. An air intake arrangement for an internal combustion engine according to claim  1 , wherein an inner volume of said auxiliary gas intake passage ( 210 ,  308 )  is determined smaller than that of said main air intake conduit. 
     
     
       10. An air intake arrangement for an internal combustion engine according to claim  9 , wherein an inner volume of said auxiliary gas intake passage ( 210 ,  308 )  is determined less than 80% of that of said main air intake conduit. 
     
     
       11. An air intake arrangement for an internal combustion engine according to claim  1 , wherein said main air intake passage, said main collector chamber ( 104 ) , and said independent branching air intake passages ( 105 )  which constitute said main air intake conduit, and said auxiliary gas intake passage ( 113 ) are formed integrally (FIG.  27  through FIG.  34 ) . 
     
     
       12. An air intake arrangement for an internal combustion engine according to claim  11 , wherein said respective independent branching air intake passages ( 105 )  are disposed around said main collector chamber ( 104 )  using a part of the wall thereof in common and includes a conduit length varying valve ( 111 )  which switches between two inlet ports provided for said respective independent branching air intake passages ( 105 ) (FIG.  27  through FIG.  34 ) . 
     
     
       13. An air intake arrangement for an internal combustion engine according to claim  12 , wherein said main air intake passage accommodating said throttle valve ( 103 )  is disposed at the center of said main collector chamber ( 104 )  with respect to the longitudinal direction thereof (FIG.  27  through FIG.  30 ) . 
     
     
       14. An air intake arrangement for an internal combustion engine according to claim  12 , wherein said main air intake passage accommodating said throttle valve ( 103 )  is disposed at one end of said main collector chamber ( 104 )  with respect to the longitudinal direction thereof (FIG.  31  through FIG.  34 ) . 
     
     
       15. An air intake arrangement for an internal combustion engine according to claim  1 , wherein a fuel injection valve receiving arrangement ( 262 ) , a fuel supply piping ( 263 )  for a fuel injection valve ( 261 )  and an air supply piping ( 264 )  for fuel atomization are integrally formed on the outer circumference of said respective independent branching air intake passages ( 205 ) at the  downstream thereof (FIG.  14 ) . 
     
     
       16. An air intake arrangement for an internal combustion engine according to claim  15 , wherein a direction of the outlet port of said auxiliary gas intake passage ( 210 )  is determined in such a manner that the blown-out gas from the outlet port ( 213 )  is introduced into said respective independent branching air passages ( 205 )  so as not to directly mix with fuel injected from the fuel injection valve ( 245 ) (FIG.  10 ) . 
     
     
       17. An air intake arrangement for an internal combustion engine according to claim  15  further comprising: 
       an assist air passage ( 310 )  connecting said main air intake passage at the upstream of said throttle valve ( 303 )  to the air supply piping ( 264 )  for fuel atomization (FIG. 15, FIG. 16 (a), FIG.  17 ) .  
     
     
       18. An air intake arrangement for an internal combustion engine according to claim  17 , wherein said assist air passage ( 310 )  branches from said auxiliary gas intake passage ( 313 )  to the air supply piping ( 264 )  for fuel injection (FIG.  15 ) . 
     
     
       19. An air intake arrangement for an internal combustion engine according to claim  1 , wherein when said control unit ( 222 )  determines one of engine operating conditions for an idle speed control, a fast idle control, a torque-up control and a fuel lean air/fuel ratio control, said control unit ( 222 )  controls to open said intake air control valve ( 211 ,  313 )  so as to supply air to the respective engine cylinders ( 206 ,  244 ,  307 )  through said auxiliary gas intake passage ( 210 ,  308 ) . 
     
     
       20. An air intake arrangement for an internal combustion engine according to claim  19 , wherein when said control unit ( 222 )  determines a change in engine operating condition from a region suitable for operating at a stoichiometric air/fuel ratio to a region suitable for operating at a fuel lean air/fuel ratio, said control unit ( 222 )  controls to hold an amount of fuel to be injected to a previous amount, then to open said intake air control valve ( 211 ,  313 )  based on an engine operating condition and thereafter to cancel the fuel amount holding (FIG.  18 (a), FIG.  18 (b), FIG.  19 a) . 
     
     
       21. An air intake arrangement for an internal combustion engine according to claim  19 , wherein when said control unit ( 222 )  determines that the engine operating condition stays in a region suitable for operating at a fuel lean air/fuel ratio, said control unit ( 222 )  compares an actual air/fuel ratio with a target air/fuel ratio and controls amount of fuel to be injected based on the comparison result (FIG.  19 (b)) . 
     
     
       22. An air intake arrangement for an internal combustion engine according to claim  19 , wherein when said control unit ( 222 )  determines that the engine operating condition stays in a region suitable for operating at a fuel lean air/fuel ratio, said control unit ( 222 )  compares an actual air/fuel ratio with a target air/fuel ratio and controls the opening degree of said intake air control valve ( 211 ,  313 )  based on the comparison result (FIG.  20 ) . 
     
     
       23. An air intake arrangement for an internal combustion according to claim  19 , wherein when said control unit ( 222 )  determines a change in engine operating condition within a region suitable for operating at a fuel lean air/fuel ratio, said control unit ( 222 )  controls the opening degree of said intake air control valve ( 211 ,  313 )  based on an engine operating condition (FIG.  23 (a), FIG.  23 (b), FIG.  24 ) . 
     
     
       24. An air intake arrangement for an internal combustion engine according to claim  19 , wherein when said control unit ( 222 )  determines a change in engine operating condition from a region suitable for operating at a fuel lean air/fuel ratio to a region suitable for operating at a stoichiometric air/fuel ratio, said control unit ( 222 )  controls to hold an amount of fuel to be injected to a previous amount, then to close said intake air control valve ( 211 ,  313 )  and thereafter to cancel the fuel amount holding (FIG.  25 (a), FIG.  25 (b), FIG.  26 ) . 
     
     
       25. An air intake arrangement for an internal combustion engine according to claim  19 , wherein when said control unit ( 222 )  determines that the engine operating condition stays in a region suitable for operating at a fuel lean air/fuel ratio, said control unit ( 222 )  compares an actual engine roughness with a target engine roughness and controls the opening degree of said intake air control valve ( 211 ,  313 )  based on the comparison result (FIG.  21 ) . 
     
     
       26. An air intake arrangement for an internal combustion engine according to claim  25 , wherein when said control unit ( 222 )  determines that the engine operating condition stays in a region suitable for operating at a fuel lean air/fuel ratio, said control unit ( 222 )  compares an actual engine roughness with a target engine roughness, and when the actual engine roughness is determined below the target engine roughness, said control unit ( 222 )  controls to increases an opening degree of said intake air control valve ( 211 ,  313 )  and repeats the comparison until the actual engine roughness exceeds the target engine roughness, and when said control unit ( 222 )  determines that the actual engine roughness exceeds the target engine roughness, the control unit ( 222 )  controls to decrease an opening degree of said intake air control valve ( 211 ),  313 )  and to rewrite the previous opening degree for the instant opening degree for the subsequent use (FIG.  22 ) . 
     
     
       27. An intake air system for a multi- cylinder internal combustion engine, comprising:    
       
         a surge tank having air outlets corresponding to respective cylinders of the engine,  
       
       
         an air cleaner chamber disposed upstream of the surge tank,  
       
       
         an air flow meter operatively arranged for measuring air flow between the air cleaner chamber and the surge tank,  
       
       
         and a throttle valve disposed between the air cleaner chamber and the surge tank for controlling air flow from the air cleaner chamber to the surge tank, and operatively supported by an integrally formed tubular part extending from the air cleaner chamber to the surge tank.  
       
     
     
       28. An intake air system according to claim  27 , wherein fuel injectors are operatively arranged with respect to the air outlets in a housing.  
     
     
       29. An intake air system according to claim  27 , wherein the air flow meter is operatively supported by the tubular part.  
     
     
       30. An intake air system according to claim  27 , wherein the air flow meter is disposed in the tubular part.  
     
     
       31. An intake air system according to claim  27 , wherein independent branching air intake conduits are operatively arranged at a peripheral region of the surge tank.  
     
     
       32. An intake air system according to claim  27 , wherein said tubular part is a resin molded part.  
     
     
       33. An intake air system according to claim  32 , wherein the air flow meter is operatively supported by the tubular part.  
     
     
       34. An intake air system according to claim  32 , wherein the air flow meter is disposed in the tubular part.  
     
     
       35. An intake air system according to claim  32 , wherein said housing contains an auxiliary air passage.  
     
     
       36. An intake air system for a multi- cylinder/multi - point injection internal combustion engine, comprising:    
       
         a surge tank having air outlets for respective cylinders of the engine, which outlets are adjacent one another in a longitudinal direction of the surge tank,  
       
       
         an air cleaner chamber disposed upstream of the surge tank,  
       
       
         and a throttle valve operatively arranged between the air cleaner chamber and the surge tank, and disposed between a central portion of a pair of the air outlets.  
       
     
     
       37. An intake air system for a multi- cylinder/multi - point injection internal combustion engine, comprising:    
       
         a surge tank having air outlets corresponding to respective cylinders of the engine,  
       
         independent branching air conduits operatively arranged at a peripheral region of the surge tank and each having a respective passage at a mid - portion thereof for communicating with the surge tank, and    
       
         valve structure operatively arranged selectively to open and close the passages.  
       
     
     
       38. An intake air system for a multi- cylinder/multi - point injection internal combustion engine, comprising:    
       
         an air cleaner assembly, and  
       
       
         a control unit operatively associated with a wall of the air cleaner assembly for controlling engine operating conditions.  
       
     
     
       39. An intake air system according to claim  38 , wherein said control unit is mounted on an inside of said air cleaner assembly.  
     
     
       40. An air intake system for a fuel injected engine, comprising: 
       
         a resin molded air intake structure body having an air intake port for taking in air which has passed through an air cleaner upstream thereof,  
       
         air leading - through ports for respective cylinders of the engine, which ports are operatively associated with the air intake port,    
       
         a throttle valve installed at the air intake port for controlling an air intake amount, and  
       
         fuel injectors provided on an associated one of the air leading - through ports for supplying fuel to the cylinders.    
     
     
       41. An air intake system according to claim  40 , wherein an air flow meter for detecting an amount of the air from the air intake port toward the cylinders is operatively arranged at an inlet portion of the air intake structure body.  
     
     
       42. An intake air system for a multi- cylinder internal combustion engine, comprising:    
       
         air intake structure body having an air intake passage, a surge tank, a common wall separating the air intake passage and the surge tank, and an air cleaner operatively arranged in the air intake passage.  
       
     
     
       43. An air intake system according to claim  42 , wherein the air intake structure body is a one- piece resin molded body.    
     
     
       44. An air intake system according to claim  43 , wherein means for supplying fuel to each fuel injector is integrally formed in the air outlets.  
     
     
       45. An intake air apparatus for a fuel injected engine, comprising: 
       
         a surge tank having air outlets for respective engine cylinders, and  
       
       
         a fuel injector for the respective engine cylinders being arranged at the air outlets between the outlets and the engine cylinders,  
       
       
         wherein the air outlets have a separate metal chamber, and wherein the fuel injector is mounted on the separate metal member.  
       
     
     
       46. An air intake body arranged laterally of an engine block, comprising: 
       
         a surge tank positioned parallel to a longitudinal direction of the engine block, and a throttle valve operative to control an amount of air which is introduced into the surge tank and arranged such that a flow direction of the air passing through the throttle valve is at a substantially right angle to a flow direction of air in the surge tank.  
       
     
     
       47. An air intake body according to claim  46 , wherein the air flow direction through the throttle valve is substantially vertical.  
     
     
       48. An air intake body according to claim  46 , wherein the throttle valve is located centrally of the surge tank as viewed in a longitudinal direction thereof.  
     
     
       49. An air intake body according to claim  46 , wherein the throttle valve is arranged above the surge tank and no higher than the top of the engine block.  
     
     
       50. An air intake body according to claim  49 , wherein the throttle valve is arranged laterally of the surge tank such that the throttle valve and surge tank have substantially the same longitudinal dimension as the engine block.  
     
     
       51. An air intake body according to claim  50 , wherein the throttle valve is arranged no higher than the top of the engine block.  
     
     
       52. An air intake system for an engine, comprising an air cleaner for cleaning air supplied to each engine cylinder, a throttle valve, a surge tank, and independent air intake conduits operatively associated with the surge tank, wherein an air passage is partitioned from the surge tank, the air cleaner is installed in the air passage above the surge tank, and the throttle valve is operatively arranged between the air passage and an inlet port of said surge tank.  
     
     
       53. An air intake system for an engine, comprising a first air passage, 
       
         a throttle valve arranged in the first air passage,  
       
         second and third air passages respectively upstream and downstream of the throttle valve and each having a cross - section area larger than the first air passage,    
       
         an air cleaner installed within the second air passage upstream of the throttle valve, and  
       
       
         a plurality of independent air intake conduits connected to each cylinder of the engine operatively communicating with the third passage downstream of the throttle valve, wherein,  
       
       
         the second and third air passages share a common wall.  
       
     
     
       54. An air intake system for an engine, comprising: 
       
         a first air passage portion in which a throttle valve is operatively arranged,  
       
       
         a second air passage portion for deflecting an air flow from said throttle valve at substantially a right angle,  
       
       
         a surge tank for receiving the deflected air flow,  
       
       
         a plurality of independent branching air intake conduits for swirling air around a periphery of the surge tank and for distributing the air from the surge tank into a respective cylinder of the engine,  
       
       
         wherein the first air passage portion is a first unitary mold material body, and  
       
       
         the second air passage portion, the surge tank and the plurality of independent branching air intake conduits is a second mold material body.  
       
     
     
       55. An air intake system according to claim  54 , wherein the molded material bodies are comprised of resin.  
     
     
       56. An air intake system for an engine, comprising a throttle valve, a surge tank arranged relative to said throttle valve such that a controllable air flow from said throttle valve is introduced therein and is supplied to each cylinder of the engine through a plurality of respective independent branching air intake conduits, and an auxiliary air intake passage opening in a portion joining the independent branching air intake conduit and the respective cylinder and supplying air to the respective cylinder by bypassing the associated independent branching air intake conduit, wherein the auxiliary air intake passage has a diameter smaller than a diameter of the independent branching air intake conduit and the auxiliary air intake passage is formed at a vicinity of an installing portion of a fuel injector.  
     
     
       57. An air intake system according to claim  56 , wherein an upstream end of the auxiliary air intake passage opens upstream of said throttle valve.  
     
     
       58. An air intake system according to claim  56 , wherein two auxiliary air intake passages are provided on the system and the two auxiliary air intake passages are formed by sandwiching a fuel injector.  
     
     
       59. An intake air apparatus for an engine, comprising: 
       
         a passage for introducing an air flow passed through a throttle valve into a surge tank by deflecting the air flow into the surge tank at substantially a right angle to the air flow through the throttle valve,  
       
       
         plural independent branching air intake conduits from said surge tank to each of which the air flow is conducted by substantially a right angle deflection, and in which the air flow is swirled with a predetermined angle, before the air flow is introduced into each of cylinders.  
       
     
     
       60. An air intake system in which an air flow amount is increased in response to actuation of an acceleration pedal, comprising: 
       
         a main air intake passage, and  
       
       
         an auxiliary air intake passage having a diameter smaller than a diameter of said main air intake passage,  
       
       
         wherein with an increase in the actuation amount of said acceleration pedal, the air flow amount from said main air intake passage is gradually increased up to a predetermined actuation amount of said acceleration pedal, an air flow is introduced from said auxiliary air intake passage, while maintaining a constant air flow rate from said main air intake passage.  
       
     
     
       61. An air intake apparatus comprising: 
       
         an air intake passage portion having an air cleaner provided therein;  
       
       
         a surge tank; and  
       
       
         an air intake passage body having a throttle valve and being operatively connected between said air cleaner case and said surge tank,  
       
       
         wherein said air cleaner case, said surge tank, and said air intake passage body are integrally formed as a body.  
       
     
     
       62. An air intake apparatus according to claim  61 , wherein said throttle valve is projectingly disposed in said surge tank.  
     
     
       63. An air intake apparatus according to claim  62 , wherein said throttle valve is projectingly disposed in a central portion of said surge tank and at an intermediate portion of plural independent branching air intake conduits associated with said surge tank.  
     
     
       64. An air intake apparatus, comprising: 
       
         an air intake passage portion having an air cleaner provided therein;  
       
       
         a surge tank;  
       
       
         plural independent branching air intake conduits opening into said surge tank;  
       
       
         a communication passage portion for connecting said air intake passage portion and said surge tank, and  
       
       
         a throttle valve installed in said communication passage portion.  
       
     
     
       65. In an air intake passage body having a portion for introducing an air flow therethrough and having a U- shaped form,    
       
         an air cleaner is installed at an uppermost upstream portion of said portion;  
       
       
         a throttle valve is operatively positioned on a bend portion of said portion;  
       
       
         a surge tank being formed at a most downstream end of said portion;  
       
       
         wherein plural independent branching air intake conduits are connected to said surge tank.  
       
     
     
       66. An air intake passage body according to claim  65 , wherein said plural independent branching air intake conduits are formed in a shape for swirling around a periphery of said surge tank.  
     
     
       67. An air intake passage body according to claim  65 , wherein said air cleaner is obliquely arranged with respect to an air flow.  
     
     
       68. An air intake passage body according to claim  65 , wherein said plural independent branching air intake conduits are arranged between a wall face of an air cleaner case of said air intake passage body and a wall face of said surge tank.  
     
     
       69. An air intake passage body according to claim  68 , wherein said wall face of said surge tank is an outer wall face of said plural independent branching air intake conduits.  
     
     
       70. An air intake passage body according to claim  68 , wherein an outer wall face of said independent branching air intake conduits is commonly shared by at least one of said wall face of said air cleaner case and said wall face of said surge tank.  
     
     
       71. An air intake system, comprising an engine control unit, and an air cleaner arranged relatively to the engine control unit for cleaning a cooling air for the unit.  
     
     
       72. An air intake apparatus, comprising an air cleaner receiving portion, and an engine control unit having a part thereof installed at a wall face of said air cleaner receiving portion to enable heat generated by the unit to be discharged toward an air flow.  
     
     
       73. An air intake apparatus according to claim  72 , wherein said air cleaner receiving portion is a resin molded member.  
     
     
       74. An air intake arrangement for an internal combustion engine, comprising: 
       
         a main air intake conduit leading to a gas intake valve for respective engine cylinders and including a main air intake passage, a surge tank and independent branching air intake passages for said respective engine cylinders connected in series;  
       
       
         a throttle valve disposed in said main air intake passage for controlling the flow rate of air passing therethrough;  
       
         an auxiliary air intake passage bypassing said main air conduit, an inlet port of said auxiliary air intake passage opening into said main air intake passage, an outlet port of said auxiliary air intake passage opening into said respective independent branching air intake passage proximate the gas intake valve for said respective engine cylinders so that a gas blown - out from said auxiliary air intake passage induces a swirl in said respective engine cylinders;    
       
         a fuel injector for controlling a supply fuel amount to said respective engine cylinders in response to an engine operating condition; and  
       
       
         a control unit for controlling an auxiliary air flow rate and fuel supply from said fuel injector;  
       
       
         wherein an engine operating condition transfers to a predetermined set different air/fuel inspection amount and controls air/fuel ratio by controlling the auxiliary air flow rate, and, after that, said control unit sets a predetermined fuel injection amount.  
       
     
     
       75. An air intake arrangement according to claim  74 , wherein, after the transfer of the engine operating condition, said control unit adjusts the fuel injection amount to control the air/fuel ratio.  
     
     
       76. An air intake arrangement according to claim  74 , wherein the air amount is determined in accordance with a result of a comparison of an air/fuel ratio before the transfer of the engine operating condition and an air/fuel ratio after the transfer of the engine operating condition.  
     
     
       77. An air intake arrangement according to claim  74 , wherein when said control unit determines at least one selected from engine operating conditions for an idle speed control, a fast idle control, a torque- up control and a fuel lean air/fuel ratio control, and said control unit controls air supply air to said respective engine cylinders through said auxiliary air intake passage.    
     
     
       78. An air intake arrangement according to claim  74 , wherein when said control unit determines that the engine operating condition remains in a region suitable for fuel lean air/fuel ratio operation, and said control unit compares an actual engine roughness with a target engine roughness and controls the flow rate of the auxiliary air based on the comparison.  
     
     
       79. An air intake arrangement for an internal combustion engine, comprising: 
       
         a main air intake conduit leading to a gas intake valve for respective engine cylinders and including a main air intake passage, a surge tank and independent branching air intake passages for said respective engine cylinders connected in series;  
       
       
         a throttle valve disposed in said main air intake passage for controlling flow rate of air passing therethrough;  
       
         an auxiliary air intake passage bypassing said main air intake conduit, an inlet port of said auxiliary air intake passage opening into said main air intake passage, an outlet port of said auxiliary air intake passage opening into said respective independent branching air intake passages proximate the gas intake valve for said respective engine cylinders so that a gas blown - out from said auxiliary air intake passage induces a swirl in said respective engine cylinders;    
       
         a swirl control device for controlling a swirl condition; and  
       
       
         a control unit for controlling an auxiliary air flow rate and fuel supply from a fuel injector,  
       
       
         wherein said control unit controls the swirl by controlling said swirl control device in response to an engine operational condition and said swirl control device controls at least one of an air flow supplied from said auxiliary air intake passage and an air inflow direction into said respective engine cylinders.  
       
     
     
       80. An air intake arrangement for an internal combustion engine according to claim  79 , wherein 
       
         said control unit controls said swirl control device to generate a swirl in said respective engine cylinders at a low speed engine operational region and to not generate a swirl in said respective engine cylinders at a high speed engine operational region.  
       
     
     
       81. An air intake arrangement according to claim  79 , wherein said control unit is configured to determine at least one selected from engine operating conditions for an idle speed control, a fast idle control, a torque- up control and a fuel lean air/fuel ratio control and to control said swirl control device so as to supply air to said respective engine cylinders through said auxiliary air intake passage.    
     
     
       82. An air intake arrangement according to claim  79 , wherein said control unit is configured to determined that the engine operating condition remains in a region suitable for fuel lean air/fuel ratio operation and to compare an actual engine roughness with a target engine roughness to control said swirl control device based on the comparison.  
     
     
       83. An air intake arrangement according to claim  79 , wherein a flow of the gas from said auxiliary air intake passage enters inside two air intake ports.  
     
     
       84. An air intake arrangement according to claim  74 , wherein a flow of the gas from said auxiliary air intake passage enters a central portion of said cylinder.  
     
     
       85. An air intake arrangement according to claim  84 , wherein the flows of the gas are two and the two gas flows are formed by sandwiching the fuel injector.  
     
     
       86. An air intake arrangement according to claim  84 , wherein an air passage is provided upstream of a valve for controlling an air flow rate of the main air intake conduit, thereby the gas flow of the main air intake conduit is controlled.  
     
     
       87. In an air intake arrangement for an internal combustion engine comprising: 
       
         a main intake conduit leading to a gas intake valve for each of respective engine cylinders and including a main intake passage, a main collector chamber and independent branching air intake passage for the respective engine cylinders connected in series;  
       
       
         a throttle valve disposed in said main intake passage for controlling a flow rate of air passing therethrough;  
       
         an auxiliary air intake passage bypassing said main air intake conduit, wherein an inlet port of said auxiliary air intake passage opens into said main air intake passage upstream of a valve for controlling the air flow rate of said main air intake conduit, and an outlet port of said auxiliary air intake passage opens into said respective independent branching air intake passages near said gas intake valve for the respective engine cylinders in such a manner that gas blown - out from said auxiliary air intake passage induces a gas swirl at the respective engine cylinders;    
       
         an intake air control valve disposed in said auxiliary air intake passage for controlling the flow rate of air passing therethrough;  
       
       
         an EGR gas passage merged into said auxiliary air intake passage downstream of said intake air control valve and an EGR gas control valve disposed in said EGR gas passage for controlling the flow rate of EGR gas passing therethrough; and  
       
       
         a control unit which determines an operating condition of the internal combustion engine and controls opening degrees of said intake air control valve and said EGR gas control valve,  
       
       
         wherein, when said control unit determines at least an engine operating condition for a fuel lean air/fuel ratio control, said control unit controls opening degree of said intake control valve so as to vary air supply to the respective engine cylinders through said auxiliary air intake passage.  
       
     
     
       88. An intake air device for an internal combustion engine of an electronic fuel injection type, wherein an air cleaner is integrated in a unit with a plurality of independent branching intake air conduits which are, in turn, integrated with an outer portion of a collector, said air cleaner being integrated within the boundaries of a longitudinal direction length of said unit, wherein the longitudinal direction of the unit is parallel to a longitudinal direction of the collector and a longitudinal direction of a main body of the engine, and further wherein the length of said unit in the longitudinal direction of the unit is not larger than the length of the main body of the engine in the longitudinal direction of the main body of the engine.  
     
     
       89. An intake air device for an internal combustion engine of an electronic fuel injection type according to claim  88 , wherein said air cleaner is arranged so that the center of said air cleaner is positioned at the center of said unit.  
     
     
       90. An intake air device for an internal combustion engine, wherein a unit is formed by integrating into a one- piece structure a plurality of independent symmetrically arranged branching intake air conduits, an air cleaner chamber having an air cleaner therein integrated with said branching intake air conduits and positioned in said unit in opposing relationship to the branching intake air conduits, and a throttle valve located to receive air from said air cleaner chamber and to introduce the air to said branching intake air conduits, wherein said throttle valve controls the flow of said air between the air cleaner chamber and the branching intake air conduits.    
     
     
       91. An intake air device according to claim  90 , wherein the unit is formed as a one- piece structure.    
     
     
       92. An intake air device for an internal combustion engine comprising a one- piece integrated structure including a plurality of independent branching intake air conduits and an air cleaner chamber having an air cleaner therein integrated with said branching intake air conduits, wherein said independent branching intake air conduits and said air cleaner chamber are formed of a molded body.    
     
     
       93. An intake air device according to claim  92 , wherein the independent branching intake air conduits and the air cleaner chamber are formed as a one- piece structure.    
     
     
       94. An intake air device according to claim  92 , wherein the molded body is comprised of resin.  
     
     
       95. An intake air device for an internal combustion engine according to claim  90  or  92 , wherein said one piece structure includes a distributing chamber for distributing air to the plurality of independent branching intake air conduits. 
     
     
       96. An intake air device for an internal combustion engine according to claim  90  or  92 , wherein said one piece structure includes a throttle chamber having a throttle valve arranged between said air cleaner chamber and said distributing chamber.  
     
     
       97. An intake air device for an internal combustion engine according to claim  90  or  92 , wherein a variable intake air valve is integrated with the branching intake air conduits.  
     
     
       98. An intake air device for an internal combustion engine according to claim  90  or  92 , wherein an EGR valve is integrated with said air cleaner chamber.  
     
     
       99. An intake air device for an internal combustion engine according to claim  45 , wherein an air flow rate measuring chamber having an intake air measuring unit and a throttle chamber having a throttle valve are integrated with said air cleaner chamber and said distributing chamber, respectively.  
     
     
       100. An intake air device for an internal combustion engine according to claim  90  or  92 , wherein a fuel gallery is integrated with the branching intake air conduits.  
     
     
       101. An intake air device for an internal combustion engine according to claim  100 , wherein said fuel gallery is comprised of an attaching portion for a fuel injection valve, a fuel pipe for supplying fuel to the fuel injection valve and an air pipe for atomizing, wherein said attaching portion, said fuel pipe and said air pipe are formed of a molded one piece structure.  
     
     
       102. An intake air device according to claim  101 , wherein the molded one- piece structure is comprised of resin.    
     
     
       103. An intake air device for an internal combustion engine comprising a plurality of independent branching intake air conduits, at least one auxiliary fluid passage having an auxiliary air control valve therein integrated with one of the independent branching intake air conduits, and an air cleaner chamber having an air cleaner therein integrated with the independent branching intake air conduits, wherein said independent branching intake air conduits, said auxiliary fluid passage and said air cleaner chamber are formed of a molded one- piece structure.    
     
     
       104. An intake air device for an internal combustion engine according to claim  103 , wherein said independent branching intake air conduits are arranged symmetrically with respect to one another and said air cleaner chamber is arranged in an opposing relationship to said independent branching intake air conduits.  
     
     
       105. An intake air device for an internal combustion engine according to claim  103 , wherein an EGR gas passage is formed of a resin and integrated with the auxiliary fluid passage in the one- piece structure.    
     
     
       106. An intake air device according to claim  103 , wherein the molded one- piece structure is comprised of resin.    
     
     
       107. An intake air device for an internal combustion engine according to claim  105 , wherein said auxiliary fluid passage is formed adjacent to a side of said one of the independent branching intake air conduits.  
     
     
       108. An intake air device for an internal combustion engine according to claim  105 , wherein ends of said auxiliary fluid passage are connected to two sides of said one of the independent branching intake air conduits.  
     
     
       109. An intake air device for an internal combustion engine according to claim  107  or  108 , wherein a throttle valve is provided in one of said independent branching intake air conduits.  
     
     
       110. An intake air device for an engine of an electronic control fuel injection type, wherein a plurality of independent branching intake air conduits, an air cleaner chamber having an air cleaner therein, a collector for distributing air to said branching intake air conduits and a throttle having a throttle valve therein are integrated in a unit, wherein air passing through said unit passes through the air cleaner chamber, the throttle valve, the collector and the independent branching intake air conduits without passing through any connecting passage such as a rubber hose, the intake air device including at least one fluid passage provided in parallel to one of said branching intake air conduits, wherein said fluid passage is located so that air flowing through the fluid passage will generate a swirl in a combustion chamber of the engine connected to said one of said branching intake air conduits, and wherein an opening area of said fluid passage into said one of said branching intake air conduits is smaller than a cross- section area of said one of said branching intake air conduits.    
     
     
       111. An intake air device for an engine of an electronic control fuel injection type, wherein a plurality of independent branching intake air conduits, an air cleaner chamber having an air cleaner therein, a collector for distributing air to said branching intake air conduits and a throttle having a throttle valve therein are integrated in a unit, the intake air device including at least one fluid passage provided in parallel to one of said branching intake air conduits, wherein said fluid passage is located so that air flowing through the fluid passage will generate a swirl in a combustion chamber of the engine connected to said one of said branching intake air conduits, and wherein an opening area of said fluid passage into said one of said branching intake air conduits is smaller than a cross- section area of said one of said branching intake air conduits.    
     
     
       112. An intake air device for an internal combustion engine, wherein a plurality of independent branching intake air conduits, a cleaner chamber having a cleaner therein integrated with the plurality of independent branching intake air conduits and an air flow rate chamber having an air flow meter therein integrated with said cleaner chamber are formed in a unit, said unit being mounted onto the engine.  
     
     
       113. An intake air device for an internal combustion engine according to claim  112 , wherein said unit includes a control unit for controlling an operating state of the engine.  
     
     
       114. An intake air device for an internal combustion engine according to claim  113 , wherein said control unit is attached onto an outer wall of the cleaner chamber.  
     
     
       115. An intake air device for an internal combustion engine, wherein a plurality of independent branching intake air conduits, a cleaner chamber having a cleaner therein integrated with the plurality of independent branching intake air conduits and a control unit for controlling an operating state of the engine are formed in a unit, said unit being mounted onto the engine.  
     
     
       116. An intake air device for an internal combustion engine according to claim  112  or  115 , wherein said unit comprised of said plurality of branching intake air conduits, said cleaner chamber and said air flow rate chamber is formed of a resin.  
     
     
       117. An intake air device for an internal combustion engine comprising a surge tank, a plurality of independent branching intake air conduits arranged along an outer periphery of the surge tank and sharing a part of a wall surface with the surge tank, a cleaner chamber having a cleaner therein and integrated with the surge tank, an air flow rate chamber having an air flow meter therein arranged between the surge tank and the cleaner chamber and integrated with the surge tank and the cleaner chamber, and a throttle chamber having a throttle valve therein, wherein said throttle chamber is arranged between the independent branching intake air conduits, and wherein lengths of each of the independent branching intake air conduits are substantially the same.  
     
     
       118. An intake air device for an internal combustion engine comprising a cleaner chamber formed in a rectangular block with an inlet port on the one side and having a cleaner therein, a tank for distributing intake air arranged in parallel to the longitudinal direction of the rectangular block of said cleaner chamber, a plurality of independent branching intake air conduits integrated with said tank, said cleaner chamber and said air distributing tank being integrated with one another, and a throttle chamber having a throttle valve therein, wherein said cleaner chamber, said air distributing tank and said throttle chamber are formed in a unit, wherein air received from said inlet port flows through said unit in a U- shaped stream.    
     
     
       119. An intake air device for an internal combustion engine according to claim  118 , wherein the air flow is bent by substantially  90  degrees between the cleaner chamber and the throttle chamber and bent by substantially  90  degrees between the throttle chamber and the air distributing tank.  
     
     
       120. An intake air device for an internal combustion engine according to claim  118 , wherein the air flow is bent by substantially  90  degrees between the air distributing tank and the plurality of branching intake air conduits.  
     
     
       121. An intake air device for an internal combustion engine according to claim  118 , wherein said unit includes a control unit for controlling an operating state of the engine.  
     
     
       122. An intake air device for an internal combustion engine according to claim  118 , wherein said control unit is attached to a wall of said cleaner chamber.  
     
     
       123. An intake air device for an internal combustion engine of an electronic control fuel injection type, wherein a plurality of independent branching intake air conduits, an air chamber including an air cleaner, a throttle chamber including a throttle valve and a distributing tank for distributing air from the throttle chamber to the independent branching intake air conduits are integrated in a unit, the length of said unit in the longitudinal direction being nearly equal to the length of the engine body in the longitudinal direction.  
     
     
       124. An intake air device for an internal combustion engine of an electronic control fuel injection type according to claim  123 , wherein said unit is formed of a resin.  
     
     
       125. An intake air device for an internal combustion engine of an electronic control fuel injection type, wherein a plurality of independent branching intake air conduits, a first chamber integrated with said plurality of independent branching intake air conduits and a second chamber having an air intake port are horizontally aligned to be integrated in a unit, a throttle chamber having a throttle valve being provided between the first chamber and the second chamber.  
     
     
       126. An intake air device for an internal combustion engine of an electronic control fuel injection type according to claim  123 , wherein a cleaner and a control unit for controlling the engine are arranged inside the first chamber.  
     
     
       127. An intake air device for an internal combustion engine of an electronic control fuel injection type according to claim  125 , wherein a flow rate measuring chamber for measuring air flow rate is arranged adjacent to the throttle chamber.  
     
     
       128. An intake air device for an engine of an electronic control fuel injection type, which includes a vessel, an air cleaner chamber formed in an air inlet port of said vessel, a plurality of independent branching intake air conduits connected to said vessel, a distributing chamber for distributing air to said independent intake air conduits formed in the outlet port of said vessel, and a throttle valve attached between said air cleaner chamber and said distributing chamber opposed to said air cleaner chamber and said distributing chamber.  
     
     
       129. An intake air device for an engine of an electronic control fuel injection type according to claim  128 , wherein said throttle valve is located outside of the independent branching intake air conduits, and wherein the air cleaner formed to have a plate- shape in a maximum length portion of the air cleaner chamber.    
     
     
       130. An intake air device for an engine of an electronic control fuel injection type according to claim  128  or  129 , wherein an engine control unit for controlling the engine is attached in a position inside the air cleaner chamber, downstream of the air cleaner, said position being accessible to permit replacing said engine control unit at the same time the air cleaner is replaced.