Patent Publication Number: US-7721705-B2

Title: Throttle management apparatus for an internal combustion engine, and engine incorporating same

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   The present invention claims priority under 35 USC 119 based on Japanese patent application No. 2006-260690, filed on Sep. 26, 2006. The subject matter of this priority document is incorporated by reference herein. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to throttle control systems for internal combustion engines, and to engines incorporating such throttle control systems. More particularly, the present invention relates to a control system which combines both mechanical and electronic control features. 
   2. Description of the Background Art 
   In the field of throttle control devices for internal combustion engines, it is well known to provide an electric (by-wire) throttle control device for controlling a throttle valve provided for each cylinder of a V-type internal combustion engine. In such an electric throttle management apparatus, an actuator is disposed between throttle bodies attached to front and rear cylinder banks, and the actuator is driven based on an electric signal generated by throttle operation. An electric throttle management apparatus of this type is disclosed, for example, in Japanese published patent document JP-A 2002-256900. 
   The technique disclosed in JP-A 2002-256900 makes it possible to arbitrarily control the output characteristic of an internal combustion engine through appropriate throttle operation. In the disclosed technique, however, all the throttle valves provided for individual cylinders are driven by one actuator, whereby an electrical control delay or driving delay is allowed to occur. Thus, when using the disclosed technique, it is difficult to improve the response speed of an internal combustion engine to an operator&#39;s request. 
   The present invention has been made in view of the above situation, and an object of the present invention is to provide a throttle management apparatus for an internal combustion engine which improves the response speed of an internal combustion engine to an operator&#39;s request, while arbitrarily controlling the output characteristic of the internal combustion engine. 
   SUMMARY OF THE INVENTION 
   To achieve the above object, in a first aspect of the invention, a throttle management apparatus for an internal combustion engine is disclosed which controls a plurality of throttle valves provided for a plurality of cylinders, respectively. The throttle management apparatus is characterized in that it includes a first throttle control device which electrically drives the throttle valves for some of the plurality of cylinders based on an electric signal generated according to selected operating conditions of a vehicle. The throttle management apparatus also includes a second throttle control device which, through manual operation of a throttle activation member such as a throttle grip or lever, mechanically drives the throttle valves for the rest of the plurality of cylinders. 
   In a second aspect of the invention, the throttle management apparatus for an internal combustion engine according to the first aspect of the invention is further characterized in that the second throttle control device has a correction device for correcting opening amounts of the throttle valves for the rest of the plurality of cylinders based on the electric signal generated according to selected operating conditions of the vehicle. 
   In a third aspect of the invention, the throttle management apparatus for an internal combustion engine according to the second aspect of the invention is further characterized in that the plurality of cylinders are grouped in banks, and the axes of the respective banks are arranged to form a V shape. In addition, an actuator of the first throttle control device and an actuator of the correction device are disposed within the V-shaped opening between the respective banks such that the actuators are longitudinally in parallel with a crankshaft disposed inside of the engine, while the actuators are mutually overlapping as viewed in a vertical direction. 
   In a fourth aspect of the invention, the throttle management apparatus for an internal combustion engine according to the second aspect of the invention is further characterized in that the plurality of cylinders are grouped in banks, and the axes of the respective banks are arranged to form a V shape, and an actuator of the first throttle control device and an actuator of the correction device are disposed between the plurality of cylinders arranged to form a V shape. In addition, the actuator of the first throttle control device drives the throttle valves for those cylinders of the plurality of cylinders which are included in a first cylinder bank. The second throttle control device, having the correction device, drives the throttle valves for the remaining cylinders, that is, those cylinders of the plurality of cylinders which are included in the other, or second, cylinder bank. 
   According to the first aspect of the invention, the first throttle control device electrically drives the throttle valves for some of the plurality of cylinders based on an electric signal generated according to selected operating conditions of the vehicle, so that the output characteristic of the internal combustion engine can be controlled arbitrarily. Also, the second throttle control device, through throttle grip operation, mechanically drives the throttle valves for the rest of the plurality of cylinders, so that, particularly during an early stage of throttle grip operation, the throttle valves can be driven by the second throttle control device with good response. This makes it possible, while electrically controlling the throttle valves, to improve the response speed of the internal combustion engine to an operator&#39;s request, namely, to improve the linearity in throttle response. 
   According to the second aspect of the invention, the correction device included in the second throttle control device corrects throttle valve opening amounts based on the electric signal generated according to selected operating conditions of the vehicle. It is therefore possible, using the second throttle control device, to arbitrarily set characteristics of the throttle valves without deterioration in the response during an early stage of throttle grip operation. This makes it possible to more arbitrarily control the output characteristic of the internal combustion engine. 
   According to the third aspect of the invention, the actuators of the first throttle control device and correction device are disposed so as to be longitudinally in parallel with the crankshaft, and between the cylinders whose axes are arranged in a V shape. By providing the actuators in this configuration, the actuators are disposed without requiring the angle formed by the V bank to be enlarged. Since the actuators are positioned to overlap each other as viewed in a vertical direction, they can be compactly disposed without interfering with each other in the longitudinal direction. 
   According to the fourth aspect of the invention, the actuator of the first throttle control device drives the throttle valves for cylinders included in one of the cylinder banks which constitute the V bank, and the second throttle control device having the correction device drives the throttle valves for cylinders included in the other of the cylinder banks which constitute the V bank. Therefore, the respective drive mechanisms of the first throttle control device and the second throttle control device including the correction device can be simplified. Also, employing a configuration in which the throttle opening amounts minutely differ between the two banks makes it possible to minutely control the output of the internal combustion engine without increasing the resolutions of the actuators. 
   Modes for carrying out the present invention are explained below by reference to an exemplary, non-limiting embodiment of the present invention shown in the attached drawings. The above-mentioned object, other objects, characteristics and advantages of the present invention will become apparent form the detailed description of the embodiment of the invention presented below in conjunction with the attached drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a side view of a motorcycle powered by an internal combustion engine which employs an embodiment of the throttle management apparatus according to the present invention. 
       FIG. 2  is an enlarged side view of an upper portion of the internal combustion engine of  FIG. 1 , showing an intake mechanism including an electric throttle management apparatus and a mechanical throttle management apparatus disposed between the front bank and the rear bank the V-type engine. 
       FIG. 3  is a side view of the intake mechanism and the throttle management apparatus of  FIG. 2 . 
       FIG. 4  is a bottom view of the intake mechanism and the electric throttle management apparatus of  FIG. 2 . 
       FIG. 5  is a cross-sectional view of an exemplary throttle management apparatus used in the embodiment. 
       FIG. 6  is a perspective view of the throttle management apparatus used in the embodiment. 
   

   DETAILED DESCRIPTION 
   A selected illustrative embodiment of the invention will now be described in some detail, with reference to the drawings. It should be understood that only structures considered necessary for clarifying the present invention are described herein. Other conventional structures, and those of ancillary and auxiliary components of the system, are assumed to be known and understood by those skilled in the art. 
   First, the configuration of a motorcycle to which the present invention is applied will be outlined with reference to  FIG. 1 . Note that, in the following, the directions front, rear, left, and right are as seen in the forward direction of the motorcycle. 
   In a motorcycle  10 , a pair of left and right mainframes  12  (only one is shown) extend rearwardly and downwardly from a head pipe  11 . A V-type multi-cylinder internal combustion engine  13  is mounted under the mainframes  12 . A swing arm  15  is vertically swingably attached to a rear portion of the mainframes  12  via a pivot shaft  14 . An upper end portion of a rear shock absorber unit  16  is attached to an upper front portion of the swing arm  15 . A rear wheel  17  is attached to a rear end portion of the swing arm  15 . A lower end portion of the rear shock absorber unit  16  is attached to a lower rear end portion of the mainframes  12  via a link unit  18 . A seat cowl  19 , serving also as a seat, extends rearwardly from above the mainframes  12 . A fuel tank  20  is installed inside the seat cowl  19 . 
   Exhaust pipes  24  and  25  are provided for each of the plural cylinders residing in a respective front cylinder head  21  of the V-type multi-cylinder engine  13 , and extend rearward from the respective front cylinder head  21 . The exhaust pipes  24  and  25  are merged together and connected to an inner right muffler  26 . Exhaust pipes  31  and  32  provided for each of the plural cylinders of the engine  13  residing in a respective rear cylinder head  28  of the engine  13 , and extend rearward from the respective rear cylinder head  28 . The exhaust pipes  31  and  32  are merged together and connected to a rear muffler  33  provided in a rear portion of the vehicle body. An intake mechanism  34  provided with the throttle management apparatus according to the present invention is installed between the cylinder heads  21  and  28  of the engine  13 . 
   A front fork  41  is rotatably attached to the head pipe  11 , a front wheel  42  is attached to a lower end portion of the front fork  41 , and a front fender  43  covers an upper portion of the front wheel  42 . The motorcycle  10  also includes an upper cowl  44 , a middle cowl  45 , a lower cowl  46 , a radiator  47 , a handlebar  48 , and a tank cover  49 . 
   Referring now to  FIG. 2 , the V-type multi-cylinder engine  13  is a V-type water-cooled, DOHC, four-cylinder engine mounted transversely on the motorcycle  10  such that a crankshaft  60  of the engine  13  is oriented in the lateral direction of the motorcycle. The V-type multi-cylinder engine  13  includes a cylinder block  63  having a front bank  61  and a rear bank  62 , the front and rear banks  61  and  62  arranged so as to form a V bank. The engine  13  also includes a crankcase  64  coupled to a lower portion of the cylinder block  63 , a front cylinder head  21  and a rear cylinder head  28  coupled to upper end portions of the front bank  61  and the rear bank  62 , respectively, and a front head cover  65  and a rear head cover  66  coupled to upper end portions of the front cylinder head  21  and the rear cylinder head  28 , respectively. 
   Plural parallel-disposed cylinders  67  (one only is shown) constitute the front bank  61  and plural parallel-disposed cylinders  68  (one only is shown) constitute the rear bank  62 . In the illustrated embodiment, two cylinders are provided in each of the front bank  61  and the rear bank  62 , but the invention is not limited thereto. The front  61  and rear  62  banks are configured such that the axes of the cylinders  67  and  68  are arranged in a V shape. A piston  70  is slidably fitted in each of the cylinders  67  and  68 . A combustion chamber  71  is formed between each of the pistons  70  and the cylinder head  21  or  28 . The cylinder head  21  includes a pair of intake ports  72  and a pair of exhaust ports  74  for the two cylinders  67  making up the front bank  61 , the intake ports  72  each having an air inlet open to the corresponding one of the combustion chambers  71  and the exhaust ports  74  each having an air outlet open to the corresponding one of the combustion chambers  71 . The cylinder head  28  includes a pair of intake ports  73  and a pair of exhaust ports  75  for the two cylinders  68  making up the rear bank  62 , the intake ports  73  each having an air inlet open to the corresponding one of the combustion chambers  71  and the exhaust ports  75  each having an air outlet open to the corresponding one of the combustion chambers  71 . Each pair of air inlets and each pair of air outlets in each of the cylinder heads are opened and closed at prescribed timing by a pair of intake valves  78  and a pair of exhaust valves  79  operated by an intake cam shaft  76  and an exhaust cam shaft  77  rotationally driven by the power of a crankshaft  60 . 
   As shown in  FIGS. 2 and 3 , the intake mechanism  34 , disposed between the front bank  61  and the rear bank  62  forming the V bank, has a throttle body  87  which includes a front throttle body section  82 , a rear throttle body section  84 , and a connection section  86  connecting the front and rear throttle body sections  82  and  84 . In the front throttle body section  82 , two intake paths  83  are formed which communicate with the intake ports  72  of the two cylinders  67  included in the front bank  61 , each of the intake paths  83  being internally provided with a throttle valve  81 . In the rear throttle body section  84 , two intake paths  85  are formed which communicate with the intake ports  73  of the two cylinders  68  included in the rear bank  62 , each of the intake paths  85  being internally provided with a throttle valve  81 . 
   In each of the front throttle body valve section  82  and the rear throttle body valve section  84 , a first injection valve  89  is provided downstream of the throttle valve  81  included in each of the intake paths  83  and  85 . A wire-mesh flame trap  88  is fitted at a top portion of each of the intake paths  83  and  85  included in the front and rear throttle body sections  82  and  84 , respectively. A second fuel injection valve  90  is disposed upward of the flame trap  88 . 
   In the present embodiment, a fuel supply pipe  91  is disposed along the axial direction of the crankshaft  60 , between the front and rear banks  61  and  62  making up the V bank. The fuel supply pipe  91  is branched into branch supply pipes  92  and  93 , allowing fuel to be supplied from the fuel supply pipe  91 , via the branch supply pipes  92  and  93 , to the second fuel injection valves  90  for the two cylinders  67  and the two cylinders  68  of the front and rear banks  61  and  62 , respectively. The fuel from the fuel supply pipe  91  is also sent, via a communication pipe  94 , to fuel pipes  95  and  96  to be then supplied to the first fuel injection valves  89  for the two cylinders  67  included in the front bank  61  and the two cylinders  68  included in the rear bank  62 , respectively. 
   The fuel injected from the first and second fuel injection valves  89  and  90  is mixed with air taken in through the intake paths  83  and  85  to generate air-fuel mixtures which are introduced into the combustion chambers  71  via the intake ports  72  or  73 . The air-fuel mixture introduced into each of the combustion chambers  71  is ignited by a spark plug  97  and burns. The resultant combustion pressure generated moves the piston  70  reciprocally, causing the piston  70  to rotationally drive the crankshaft  60  via a connecting rod  98 . 
   As shown in  FIG. 2 , an electric throttle management apparatus  100 , which is a first throttle control device, and a mechanical throttle management apparatus  101 , which is a second throttle control device, are disposed between the two intake paths  83  included in the front throttle body section  82 , and the two intake paths  85  included in the rear throttle body section  84 . As described above, the intake paths  83  and  85  are disposed between the two cylinders  67  included in the front bank  61  and the two cylinders  68  included in the rear bank  62 , the two cylinders  67  and the two cylinders  68  being disposed to form a V shape. 
   Based on an electric signal generated according to selected operating conditions of the vehicle, the electric throttle management apparatus  100  electrically drives the two throttle valves  81  for the two cylinders  67  included in the front bank  61  out of the throttle valves  81  for the cylinders  67  and  68  of the two banks making up the V bank. The “selected operating conditions of the vehicle” refer to various parameters including those indicative of selected operating conditions of the internal combustion engine: for example, throttle condition, vehicle speed, acceleration, and wheel slip ratio. 
   As shown in  FIG. 5 , the electric throttle management apparatus  100  is housed in a case  111  and a motor housing section  112 , the motor housing section  112  having a bottomed cylindrical shape and being provided in the case  111 . The electric throttle management apparatus  100  includes an actuator  113  longitudinally extending in parallel with the crankshaft  60 , a first small gear  115  mounted on a drive shaft  114  of the actuator  113 , a support shaft  117  supported, via a pair of bearings  116 , by the case  111 , a large gear  118  fixed to the support shaft  117  and engaging the first small gear  115 , a second small gear  119  which is fixed to the support shaft  117  and rotates integrally with the large gear  118 , an output shaft  121  supported, via a pair of bearings  120 , by the case  111  and partly projecting from the case, and a fan-shaped output gear  122  formed integrally with the output shaft  121  and engaging the second small gear  119 . 
   As shown in  FIGS. 3 and 6 , the electric throttle management apparatus  100  has a link mechanism  130  which includes a first link member  131  linked at one end to the output shaft  121 , a second link member  133  linked to the other end of the first link member  131  via a link shaft  132 , and a third link member  135  linked to an end of the second link member  133  via a link shaft  134 . One end of the third link member  135  of the link mechanism  130  is linked to a valve shaft  136  supporting the two throttle valves  81  included in the front bank  61 . 
   The electric throttle management apparatus  100  further includes an operation amount detection sensor (not shown) which detects the amount of operation (amount of rotation) by the rider of a throttle manipulation member such as a throttle grip  50 . The electric throttle management apparatus  100  still further includes a controller (not shown) which controls the actuator  113  based on various parameters such as values detected by the operation amount detection sensor, vehicle speed, acceleration, and wheel slip ratio. Therefore, when an operation of the throttle activation member (such as a throttle grip  50 ) causes the actuator  113  to rotate, the output shaft  121  rotates causing, via the link mechanism  130 , the two throttle valves  81  included in the front bank  61  to rotate. 
   The mechanical throttle management apparatus  101  mechanically drives, through manual operation of the throttle activation member such as the throttle grip  50 , the throttle valves  81  for the two cylinders  68  included in the rear bank  62  out of the throttle valves  81  provided for the cylinders  67  and  68  as shown in  FIG. 3 . Being provided with a correction device  102 , the mechanical throttle management apparatus  101  also adjusts the opening amount of each of the throttle valves  81  for the two cylinders  68  based on an electric signal generated according to selected operating conditions of the vehicle. 
   As shown in  FIG. 5 , the mechanical throttle management apparatus  101  includes a drum  200  linked via a cable  51  to the throttle activation member (i.e., throttle grip  50 ), an input shaft  201  attached to the drum  200 , a power transmission device  202  linked to the input shaft  201 , an output shaft  187  held by the power transmission device  202 , a link mechanism  180  linked to the output shaft  187 , an intermediate gear  204  engaged with a large gear  203  provided in the power transmission device  202 , a drive gear  205  engaged with the intermediate gear  204 , an actuator  206  which is, being linked to the drive gear  205  and longitudinally extending in parallel with the crankshaft  60 , included in the correction device  102 , and an accommodation case  207  which accommodates most part of the input shaft  201 , the power transmission device  202 , most part of the output shaft  187 , the intermediate gear  204 , the drive gear  205 , and the actuator  206 . 
   The drum  200  has a circumferential cable groove  208  around which a cable  51  can be wound, and a torsion coil spring  209  is set between the drum  200  and the accommodation case  207 . The torsion coil spring  209  biases the drum  200  in the direction opposite to the direction of rotation of the drum  200  caused by turning of the throttle grip  50 . Specifically, it causes the throttle valves  81  to be elastically biased in the direction of closing. The input shaft  201  is rotatably attached to the accommodation case  207  via a bearing  210 , and has an input bevel gear  211  formed integrally with an end portion thereof. 
   The power transmission device  202  includes a split-type case section  214  rotatably attached to the accommodation case  207  via bearings  212  and  213 , a cross-shaped support shaft  215  attached to the case section  214 , small bevel gears  216  rotatably attached to the support shaft  215 , and an input bevel gear  211  and an output bevel gear  217  engaged with the small bevel gears  216 , respectively. 
   The case section  214  is rotatably attached to the input shaft  201  via a bearing  218  and to the output shaft  187  via a bearing  219 . The case section  214  includes a case section body  220  and a cover section  221  provided on the input shaft  201  side to cover an opening portion of the case section body  220 . The case section body  220  is formed integrally with the large gear  203  and supports the support shaft  215 . The cover section  221  is attached to the case section body  220  with bolts  222 . 
   The output bevel gear  217  is formed integrally with the output shaft  187 . The intermediate gear  204  is a component rotatably attached to the accommodation case  207  via bearings  223 . The drive gear  205  is a component rotatably attached to the accommodation case  207  via a bearing  224  and linked to a rotary shaft  225  of the actuator  206  with a bolt  226 . 
   The actuator  206  is covered by a motor case  227 . It is clamped together with the motor case  227  to the accommodation case  207  by bolts  228 . The accommodation case  207  includes a first case  229  and a second case  230  which are coupled to each other by plural bolts  231 . 
   The axes of the input shaft  201  and output shaft  187  are aligned on a single straight line. The rotary shaft  225  of the actuator  206  is disposed in parallel with the input shaft  201  and the output shaft  187 . Namely, the actuator  206 , having a cylindrical shape and longitudinally extending in parallel with the rotary shaft  225 , is also disposed in parallel with the input shaft  201  and the output shaft  187 . 
   A nut  232  is provided for attaching the drum  200  to the input shaft  201 ,  233  a bearing  233  is provided between an end portion of the output shaft  187  and an end portion of the second case  230  to rotationally support the output shaft  187 , a collar  234  is provided around the output shaft  187  at a location in a section between the bearings  219  and  233 , an annular spacer  235  is provided around the output shaft  187  at a location in a section between the bearing  233  and a first arm member  188 , a nut  236  is provided for attaching the first arm member  188  to an end portion of the output shaft  187 , and a conductor  237  is connected to the actuator  206  for energizing the actuator  206 . 
   As shown in  FIGS. 3 and 6 , the mechanical throttle management apparatus  101  has a link mechanism  180  which includes a first link member  181  attached, at one end thereof, to an end portion of the output shaft  187  to be rotatable integrally with the output shaft  187 , a second link member  183  one end of which is attached to the other end of the first link member  181  via a link shaft  182 , and a third link member  185  linked to the other end of the second link member  183  via a link shaft  184 . A valve shaft  186  holding the throttle valves  81  for the two cylinders  68  included in the rear bank  62  is attached to the third link member of this link mechanism. 
   In the mechanical throttle management apparatus  101 , when the throttle grip  50  is turned to open the throttle valves, the rotation of the throttle grip  50  is transmitted to the drum  200  via a cable  51 . 
   When the actuator  206  of the correction device  102  is kept stationary, the large gear  203 , engaged with the drive gear  205  via the intermediate gear  204 , stays still. When, in this state, the input shaft  201  connected to the drum  200  rotates, the rotation of the input shaft  201  is transmitted from the input bevel gear  211  to the small bevel gear  216 , then from the small bevel gear  216  to the output bevel gear  217 , causing the output shaft  187  to rotate. Since, at this time, the small bevel gear  216  rotates on its own axis, the output shaft  187  rotates at the same rotational speed as the input shaft  201  and in the opposite direction from the input shaft  201 . 
   When the actuator  206  of the correction device  102  is operated to make the rotary shaft  225  of the actuator  206  rotate in the same direction as the input shaft  201  (i.e. in the opposite direction from the output shaft  187 ), the large gear  203  rotates in the same direction as the input shaft  201  and the small bevel gear  216  revolves while rotating on its own axis, causing the output shaft  187  to rotate more slowly than the input shaft  201 . 
   Conversely, when the rotary shaft  225  of the actuator  206  is rotated in the opposite direction from the input shaft  201  (i.e. in the same direction as the output shaft  187 ), the large gear  203  rotates in the opposite direction from the input shaft  201  and the small bevel gear  216  revolves while rotating on its own axis, causing the output shaft  187  to rotate faster than the input shaft  201 . 
   The mechanical throttle management apparatus  101  further includes an operation amount detection sensor (not shown) which detects the amount of operation (amount of rotation) by the rider of the throttle grip  50 , and includes a controller (not shown) which controls the actuator  206  based on values detected by the operation amount detection sensor. The mechanical throttle management apparatus  101  mechanically drives the two throttle valves  81  included in the rear bank  62  according to the rotation of the throttle grip  50  that is transmitted to the drum  200  via a throttle cable  51 , i.e. according to throttle grip  50  operation. When the two throttle valves  81  are driven, the controller (not shown) adjusts, as required, the rotation of the output shaft  187  by controlling the actuator  206  based on various parameters such as values detected by the operation amount detection sensor (not shown), vehicle speed, acceleration, and wheel slip ratio. 
   The electric throttle management apparatus  100  and mechanical throttle management apparatus  101  configured as described above are fixed to the throttle body  87  by attaching fixing portions  240  and  241  shown in  FIGS. 3 and 6  to lower portions of the throttle body  87  with clamping members  242  (see  FIG. 3 ). When the throttle management apparatus  100  and  101  fixed as described above, the actuator  113  of the electric throttle management apparatus  100  and the actuator  206  of the correction device  102  are disposed between the cylinders  67  and cylinders  68 , which are arranged in a V shape. The actuator  113  of the electric throttle management apparatus  100  and the actuator  206  of the correction device  102  are positioned such that they are longitudinally in parallel with the crankshaft  60  while overlapping each other as viewed in the vertical direction. 
   As shown in  FIG. 4 , three throttle opening sensors  250 ,  251 , and  252  are attached to one end portion of the valve shaft  136  included in the front bank  61  and two end portions of the valve shaft  186  included in the rear bank  62 , respectively. They detect the opening amount of the throttle valves  81  included in the front bank  61  and the rear bank  62 , and the rotation angle of the drum  200 . 
   According to the embodiment described above, the electric throttle management apparatus  100  drives the two throttle valves  81  for the two cylinders  67  included in the front bank  61  of the V-shaped bank based on an electric signal generated according to selected operating conditions of the vehicle, so that the output characteristic of the V-type multi-cylinder engine  13  can be arbitrarily controlled. Furthermore, the throttle valves  81  for the two cylinders  68  included in the rear bank  62  that forms, together with the front bank  61 , the V-shaped bank, are mechanically driven by the mechanical throttle management apparatus  101 . Therefore, during an early stage of throttle grip  50  operation in particular, the two throttle valves  81  can be driven by the mechanical throttle management apparatus  101  with good response. This makes it possible, while electrically controlling the throttle valves  81 , to improve the response of the V-type multi-cylinder engine  13  to an operator&#39;s request, namely, to improve the linearity in throttle response. The above effects are obtained using the configuration including both the electric throttle management apparatus  100  and the mechanical throttle management apparatus  101 . In the configuration, the drum  200  on which the cable  51  is wound is required only at one location. Also, the actuator  113  of the electric throttle management apparatus  100  can be made relatively short in the longitudinal direction. Thus, the overall configuration can be made compact. 
   With the correction device  102  of the mechanical throttle management apparatus  101  adjusting the openings of the throttle valves  81  based on an electric signal generated according to selected operating conditions of the vehicle, it is possible to arbitrarily set characteristics of the throttle valves  81  without a deterioration in the response during an early stage of throttle grip  50  operation. This makes it possible to more arbitrarily control the output characteristics of the V-type multi-cylinder engine  13 . 
   Furthermore, the actuators  113  and  206  of the electric throttle management apparatus  100  and correction device  102  are disposed so as to be longitudinally in parallel with the crankshaft  60 , and positioned between the cylinders  67  and cylinders  68 . That is, the actuators  113  and  206  are disposed in the V-shaped opening between the front bank  61  and the rear bank  62  so as extend in the direction of the crankshaft  60 . When disposed in this configuration, the actuators  113  and  206  do not require the angle formed by the V bank to be enlarged. The actuators  113  and  206 , being positioned at different heights, cannot interfere with each other in the longitudinal direction, so that they can compactly disposed. 
   The throttle valves  81  for the cylinders  67  included in the front bank  61  of the V bank are driven by the actuator  113  of the electric throttle management apparatus  100 , and the throttle valves  81  for the cylinders  68  included in the rear bank  62  of the V bank are driven by the mechanical throttle management apparatus  101  including the correction device  102 , so that the respective drive mechanisms of the electric throttle management apparatus  100  and the mechanical throttle management apparatus  101  including the correction device  102  can be simplified. Also, employing a configuration in which the throttle openings minutely differ between the front bank  61  and the rear bank  62  makes it possible to minutely control the output of the V-type multi-cylinder engine  13  without raising the resolutions of the actuators  113  and  206 . 
   While a working example of the present invention has been described above, the present invention is not limited to the working example described above, but various design alterations may be carried out without departing from the present invention as set forth in the claims. 
   For example, even though the actuators  113  and  206  of the electric throttle management apparatus  100  and the correction device  102 , respectively, are disposed at different heights, they may be disposed along each other at a same height. In such a configuration, too, they can be compactly disposed without interfering with each other in the longitudinal direction.