Patent Publication Number: US-11655785-B2

Title: Engine, outboard motor and boat

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2021-032849 filed on Mar. 2, 2021, the content of which is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     This invention relates to an engine, an outboard motor, and a boat. 
     Description of the Related Art 
     Conventionally, there has been known a device that has two throttle bodies and adjusts an amount of intake air sucked in by an air inlet port of each bank arranged in a V-type by using these two throttle bodies (e.g., see JP2006-062413A). 
     In the case of a device having two throttle bodies such as the device described in JP2006-062413A, when only the temperature of air flowing into one throttle body is detected, an error may occur between the actual intake air temperature guided to each bank and the detected intake air temperature. 
     SUMMARY OF THE INVENTION 
     An aspect of the present invention is a V-type multi-cylinder engine including a pair of banks. The engine includes: an intake member forming an intake passage through which air is guided from outside; a pair of throttles each configured to regulate an amount of the air sucked into each of the pair of banks through the intake passage; and one single temperature sensor configured to detect a temperature of the air in the intake passage. The intake member includes a pair of openings downstream in a flowing direction of the air. Each the pair of throttles is connected to each of the pair of openings. The temperature sensor is disposed between the pair of openings. 
     Another aspect of the present invention is an outboard motor, including: the engine; and a propeller driven by the engine to rotate. 
     Another aspect of the present invention is a boat, including: the outboard motor; and a hull mounted with the outboard motor. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The objects, features, and advantages of the present invention will become clearer from the following description of embodiments in relation to the attached drawings, in which: 
         FIG.  1    is an external perspective view of a boat on which an outboard motor according to an embodiment of the present invention is mounted; 
         FIG.  2    is a longitudinal cross-sectional view illustrating a configuration of a main component of the outboard motor according to the embodiment of the present invention with a part of an engine cover cut away; 
         FIG.  3    is a plan view of an engine included in the outboard motor according to the embodiment of the present invention; 
         FIG.  4    is a perspective view of a silencer body of an air intake silencer according to the embodiment of the present invention; 
         FIG.  5    is a cross-sectional view taken along line V-V of  FIG.  4   ; 
         FIG.  6    is an enlarged view of a main component of an air intake device included in the engine according to the embodiment of the present invention; 
         FIG.  7    is a view illustrating a recirculation chamber unit included in the silencer body in  FIG.  5   ; and 
         FIG.  8    is a view of the tilted up outboard motor according to the embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     An embodiment of the present invention will be described below with reference to  FIGS.  1  to  8   .  FIG.  1    is an external perspective view of a boat  100  on which an outboard motor  1  according to the present embodiment is mounted. Note that, hereinafter, for convenience, the front-back direction (propulsion direction), the left-right direction, and the up-down direction are defined as illustrated in the drawing, and each unit will be described according to this definition. 
     As illustrated in  FIG.  1   , the boat  100  includes a hull  101  and the outboard motor  1  attached to the stern of the hull  101 , and is configured such that the hull  101  is propelled by power of the outboard motor  1  driven in response with an operation of a boat operator. In front of a cockpit  102  of the hull  101 , a steering wheel  103  that can be rotated by the operator and a shift lever (shift/throttle lever)  104  that can be shifted by the operator are provided. A shift lever  104  is configured to be capable of shift operation in the forward direction or the backward direction from the neutral position, and inputs a switching instruction from the neutral position to the forward or backward direction and an adjustment instruction of the engine rotation speed in response to the operation of the boat operator. 
       FIG.  2    is a longitudinal cross-sectional view illustrating the configuration of a main component of the outboard motor  1  with a part of an engine cover  2   b  cut away. As illustrated in  FIG.  2   , the outboard motor  1  is attached to a transom board  101   a  located at the stern of the hull  101  via a stern bracket  10  provided in front. A swivel case  11  is provided behind the stern bracket  10 , and a swivel shaft  12  rotatable about a vertical axis is housed in the swivel case  11 . The swivel shaft  12  is connected to a steering electric motor  14  via a reduction gear mechanism (not illustrated) and a mount frame  13 , and constitutes a steering shaft that steers the hull  101  to the right and left in response to the rotation of the steering electric motor  14 . 
     Power tilt units (not illustrated) for tilting up and down or trimming up and down the outboard motor  1  are provided on both right and left sides of the stern bracket  10 . The power tilting unit includes a tilt angle adjustment hydraulic cylinder and a trim angle adjustment hydraulic cylinder, and the swivel case  11  rotates with a tilting shaft  15  as a rotation axis by extending and contracting these hydraulic cylinders. This causes the outboard motor  1  to be tilted up and down or trimmed up and down. 
     An engine  2  described later is mounted on an upper portion of the outboard motor  1 , and the engine  2  is covered with an engine cover  2   b . A crankshaft  31  of the engine  2  extends in the vertical direction, and the lower end of the crankshaft  31  is connected to the upper end of a drive shaft  20  extending in the vertical direction. The lower end of the drive shaft  20  is connected to one end of a propeller shaft  22  extending in the horizontal direction via a shift mechanism  21 , and a propeller  23  is attached to the other end of the propeller shaft  22 . The propeller shaft  22  is disposed such that an axis  22   a  becomes substantially parallel to the water surface when the trim angle is in a state of the initial angle. 
     The shift mechanism  21  includes a forward bevel gear  21   a  and a backward bevel gear  21   b  that are connected to the drive shaft  20  and rotate, a clutch  21   c  that engages the propeller shaft  22  with either the forward bevel gear  21   a  or the backward bevel gear  21   b , a shift rod  21   d , and a shift slider  21   e . An output shaft of a shift electric motor  24  that performs a shift change by operating the shift mechanism  21  is connected to the upper end of the shift rod  21   d  via a reduction gear mechanism  25 , and the shift slider  21   e  is connected to the lower end of the shift rod  21   d.    
     When the shift electric motor  24  is driven in response to the operation of the shift lever  104  by the boat operator, the shift rod  21   d  and the shift slider  21   e  are appropriately displaced to operate the clutch  21   c , and the shift mechanism  21  is switched between neutral, forward, and backward. When the shift mechanism  21  is forward or backward, the rotation of the drive shaft  20  is transmitted to the propeller shaft  22  via the shift mechanism  21 , the propeller  23  rotates, and the hull  101  is propelled in the forward direction or the backward direction. 
       FIG.  3    is a plan view of the engine  2 . As illustrated in  FIGS.  2  and  3   , the engine  2  is a V-type multi-cylinder engine in which a pair of banks (cylinder rows) formed by arranging a plurality of cylinders in the up-down direction are arranged in a V shape, and as illustrated in  FIG.  2   , includes a V-type six-cylinder engine having three cylinders in each bank. Hereinafter, the right side bank of the engine  2  is referred to as a first bank RB 1 , and the left side bank is referred to as a second bank LB 1 . 
     The engine  2  includes an engine body  2   a  having a first bank RB 1  and a second bank LB 1 , an air intake device  7  provided above the engine body  2   a , a mount case  8  provided below the engine body  2   a , and an oil pan  9  provided below the mount case  8 . 
     The engine body  2   a  includes: a crankcase  3  housing the crankshaft  31  extending in the vertical direction; a cylinder block  4  attached to the crankcase  3  and formed with a cylinder  40 ; a cylinder head  5  attached to the cylinder block  4  and provided with an air inlet port  51  and an air outlet port  52  communicating with the cylinder  40 ; and a cylinder head cover  6  covering the cylinder head  5 . Each of the first and second banks RB 1  and LB 1  includes the cylinder block  4 , the cylinder head  5 , and the cylinder head cover  6 . 
     The crankcase  3  and the cylinder block  4  constitute a crank chamber  30 , and the crankshaft  31  is housed in the crank chamber  30 . The lower end of the crankshaft  31  extends downward from the crank chamber  30  and is connected to the upper end of the drive shaft  20 . The upper end of the crankshaft  31  extends upward from the crank chamber  30 , and a crank pulley  32  is attached thereto. 
     In the cylinder block  4 , three cylinders  40  arranged in the up-down direction are formed in each of the first bank RB 1  and the second bank LB 1 . Each cylinder  40  slidably houses a piston  41 , and one end of a connecting rod  42  is coupled to each piston  41 . The other end of the connecting rod  42  is coupled to the crankshaft  31 , and the piston  41  slides in the cylinder  40  to rotate the crankshaft  31 . 
     The cylinder head  5  and the cylinder block  4  constitute a combustion chamber  50  for each cylinder  40 , and the air inlet port  51  and the air outlet port  52  communicate with each combustion chamber  50 . The air inlet port  51  and the air outlet port  52  are provided with an air inlet valve  54  and an air outlet valve  55 . A camshaft  53  extending in the vertical direction is rotatably supported on the back side of the cylinder head  5 , and the rotation of the camshaft  53  drives the air inlet valve  54  and the air outlet valve  55  to open and close the air inlet port  51  and the air outlet port  52 . 
     A cam pulley  56  is attached to the upper end of the camshaft  53 . A timing belt  57  is wound around the cam pulley  56  and the crank pulley  32 , and when the crankshaft  31  rotates, the camshaft  53  also rotates via the timing belt  57 . The timing belt  57  is also wound around an idle pulley  58  forming a track of the timing belt  57  and a tensioner pulley  59  that applies predetermined tension to the timing belt  57 . 
     The cylinder head cover  6  and the cylinder head  5  include a cam chamber  60  that houses the camshaft  53 , and a gas chamber (not illustrated) into which blow-by gas flows via the cylinder block  4 , the cylinder head  5 , and the like. A breather tube  61  ( FIG.  3   ) communicating with the gas chamber is connected to the cylinder head cover  6 , and the blow-by gas flowing into the gas chamber is introduced into the air intake device  7  via the breather tube  61 . 
     The mount case  8  is interposed between the engine body  2   a  and the oil pan  9 , and supports the engine body  2   a . An oil reservoir space formed between the mount case  8  and the oil pan  9  and an internal space of the cylinder head cover  6  communicate with each other via an oil return tube  80 , and the oil flowing into the internal space of the cylinder head cover  6  flows into the oil pan  9  (oil reservoir space) via the oil return tube  80 . 
     The oil pan  9  stores oil for lubricating the inside of the engine body  2   a . The oil stored in the oil pan  9  is pumped up by an oil pump  91 , passes through an oil path (not illustrated) formed in the mount case  8 , the cylinder block  4 , and the cylinder head  5 , and is supplied to the bearing portion of the crankshaft  31  and the camshaft  53  and the like. 
     The air intake device  7  guides the air introduced from an air introduction portion  2   c  formed in the engine cover  2   b  to the air inlet port  51  of the combustion chamber  50  of each of the plurality of cylinders  40  formed in each of the first and second banks RB 1  and LB 1 . The air intake device  7  guides, to the air inlet port  51 , and recirculates the blow-by gas introduced from the internal space of the cylinder head cover  6  via the breather tube  61  together with the air. 
     The air intake device  7  includes an air intake silencer  70 , a pair of left and right throttle bodies  71 , an intake manifold  72 , and a single temperature sensor  73 . The air intake silencer  70  includes a silencer body  74  having an exhaust heat unit  75  and a chamber unit  76 , a first cover  75   a  covering the exhaust heat unit  75 , and a second cover  76   a  covering the chamber unit  76 . The first cover  75   a  covers the exhaust heat unit  75  via a seal member  75   b , thereby forming an exhaust heat space. The second cover  76   a  has a pair of left and right air inlet ports (not illustrated) in the rear part, and covers the chamber unit  76  via a seal member  76   b , thereby forming an air intake space (air intake passage). 
       FIG.  4    is a perspective view of the silencer body  74  of the air intake silencer  70 . As illustrated in  FIG.  4   , the silencer body  74  is formed in a shape in which the length in the left-right direction gradually increases from the front toward the rear, and constitutes a substantially triangular shape in plan view. The silencer body  74  includes the exhaust heat unit  75  located in front of the air intake silencer  70  and the chamber unit  76  located behind the air intake silencer  70 . 
     The exhaust heat unit  75  is provided with an exhaust fan (not illustrated), and the heat of the engine body  2   a  is introduced into the exhaust heat space via this exhaust fan. The air flowing in from the air introduction portion  2   c  of the engine cover  2   b  is guided to the chamber unit  76  and introduced into the air intake passage. Specifically, the air flowing in from the air introduction portion  2   c  is guided in the vertical direction by a descending flow path (arrow A in  FIG.  2   ), is reversed from the rear to the front (arrow B in  FIG.  2   ) while being branched in the left-right direction by the reverse flow path, and then flows into the air intake passage of the chamber unit  76  via the pair of left and right air inlet ports of the second cover  76   a  (arrow C in  FIG.  2   ). 
       FIG.  5    is a cross-sectional view taken along line V-V of  FIG.  4   . As illustrated in  FIG.  5   , the chamber unit  76  has a pair of left and right connection portions  77  configured to be able to connect each of the pair of throttle bodies  71  at a rear end part  76   c . Each of the pair of connection portions  77  includes an opening part  77   a  formed in the rear end part  76   c  and communicating with the air intake passage, and a cylindrical part  77   b  provided to extend rearward from an opening part  77   a  and configured to be able to connect each of the pair of throttle bodies  71 . A frame trap  77   c  ( FIG.  7   ) is disposed in the opening part  77   a , and a grommet  71   b  ( FIG.  6   ) is disposed in the cylindrical part  77   b.    
     One end of each of the pair of throttle bodies  71  is connected to each of the pair of left and right cylindrical parts  77   b  formed in the chamber unit  76  via the grommet  71   b , and the other end is connected to the intake manifold  72 . Each of the pair of throttle bodies  71  has a throttle valve  71   a  opened and closed by an actuator (not illustrated), and the amount of intake air sucked into the air inlet port  51  of each of the first and second banks RB 1  and LB 1  is adjusted by adjusting the opening of the throttle valve  71   a.    
     One end of the intake manifold  72  is connected to the other end of each of the pair of throttle bodies  71 , and the other end is connected to an air intake pipe communicating with the air inlet port  51  of each of the first and second banks RB 1  and LB 1 . The intake manifold  72  guides the air whose amount of intake is adjusted by the pair of throttle bodies  71  to the air inlet port  51  of each of the first and second banks RB 1  and LB 1  via the air intake pipe. 
     An injector is connected to the air intake pipe, and the injector injects gasoline fuel into air whose amount of intake is adjusted by the throttle valve  71   a . The injected fuel mixes with the sucked air to form an air-fuel mixture, and the air-fuel mixture flows into the combustion chamber  50  when the air inlet port  51  is opened. The air-fuel mixture flowing into the combustion chamber  50  is ignited by an ignition plug and combusted, and the piston  41  is driven to rotate the crankshaft  31 . The exhaust gas generated by the combustion is discharged to the outside of the engine  2  through the exhaust pipe when the air outlet port  52  is opened. 
     The temperature sensor  73  includes a sensor unit  73   a  that detects temperature and a coupler portion  73   b  that fixes the sensor unit  73   a , and the sensor unit  73   a  detects temperature of air flowing into the pair of throttle bodies  71 . 
     In the case of the V-type engine  2  having the pair of throttle bodies  71  as described above, when only the temperature of the air flowing into one throttle body  71  is detected, there is a possibility that an error occurs between the temperature of the air sent to the air inlet port  51  of each of the first and second banks RB 1  and LB 1  and the temperature detected by the temperature sensor  73 . 
     Therefore, in the present embodiment, the temperature of the air immediately before flowing into each of the pair of throttle bodies  71 , that is, the temperature of the air in the air intake passage is detected between the pair of opening parts  77   a  provided in the chamber unit  76  of the air intake silencer  70 . This makes it possible to reduce an error between the temperature of the air sent to the air inlet port  51  of each of the first and second banks RB 1  and LB 1  and the temperature detected by the temperature sensor  73 . In order to satisfactorily achieve such an operation, in the present embodiment, the engine  2  of the outboard motor  1  is configured as follows. 
       FIG.  6    is an enlarged view of a main component of the air intake device  7  included in the engine  2  according to the present embodiment. As illustrated in  FIG.  6   , a sensor attachment portion  78  configured to be able to be attached with the temperature sensor  73  is provided between the pair of opening parts  77   a  formed in the rear end part  76   c  of the chamber unit  76 . The sensor attachment portion  78  is provided substantially at the center between the pair of opening parts  77   a  at the rear end part  76   c  of the chamber unit  76  ( FIG.  5   ). 
     The sensor attachment portion  78  is configured to be able to be attached with the coupler portion  73   b  in a state where the sensor unit  73   a  is inserted from the rear such that the sensor unit  73   a  is positioned in the air intake passage in the chamber unit  76 . That is, in a state where the temperature sensor  73  is attached to the sensor attachment portion  78 , the sensor unit  73   a  is positioned in the air intake passage in a state of being substantially parallel to the front-rear direction, and the coupler portion  73   b  is positioned in an idle space between the pair of cylindrical parts  77   b . The idle space here means a space that is not utilized, and in the air intake device  7 , the idle space includes a space from between the pair of connection portions  77  connected to the pair of throttle bodies  71  to between the throttle bodies  71 . 
     The chamber unit  76  further includes a recirculation chamber unit  79  that recirculates the blow-by gas from the engine body  2   a  (the gas chamber of the cylinder head cover  6 ).  FIG.  7    is a view illustrating the recirculation chamber unit  79  included in the chamber unit  76  of the silencer body  74  in  FIG.  5   .  FIG.  7    illustrates a state in which a member  74   b  ( FIG.  5   ) constituting a part of the silencer body  74  is removed from the silencer body  74  to expose each of the pair of opening parts  77   a  and the like. The member  74   b  is configured to be fixable to the silencer body  74  with a screw member, a bolt, a nut, or the like. 
     As illustrated in  FIGS.  5  and  7   , the recirculation chamber unit  79  is provided between the pair of cylindrical parts  77   b  and below the sensor attachment portion  78 . That is, the recirculation chamber unit  79  is also provided in the idle space existing from between the connection portions  77  to between the throttle bodies  71 . 
     The recirculation chamber unit  79  includes a chamber unit body  79   a  into which the blow-by gas flows, a connection portion  79   b  to which the breather tube  61  is connected, and a pair of communication portions  79   c  communicating with the chamber unit body  79   a  and the pair of cylindrical parts  77   b . The chamber unit body  79   a  is formed in a groove shape in the silencer body  74 , and constitutes a recirculation passage by attaching the member  74   b  to the silencer body  74 . The shape and size of the chamber unit body  79   a  are not limited thereto, and can be appropriately changed. The connection portion  79   b  is provided in the member  74   b  and communicates the recirculation passage of the chamber unit body  79   a  and the space inside the tube of the breather tube  61 . The connection portion  79   b  is provided to protrude upward from the member  74   b , and is configured to cover the connection portion  79   b  with the tip of the breather tube  61  so that the breather tube  61  is attached. Each of the pair of communication portions  79   c  allows the internal space of each of the pair of cylindrical parts  77   b  to communicate with the recirculation passage of the chamber unit body  79   a.    
       FIG.  8    is a view of the outboard motor  1  that is tilted up. As illustrated in  FIG.  8   , when the outboard motor  1  is tilted up, the engine  2  located above the outboard motor  1  rotates forward with the tilting shaft  15  as a rotation axis. Accordingly, the air intake silencer  70  also rotates forward. Therefore, with the outboard motor  1  tilted up, the front side of the air intake silencer  70  is positioned below and the rear side thereof is positioned above. Due to this, the temperature sensor  73  attached to the rear side of the air intake silencer  70  (the rear end part  76   c  of the chamber unit  76 ) is held in a state of being positioned above with the outboard motor  1  tilted up. At this time, the sensor unit  73   a  faces downward. Therefore, even when the boat  100  is stored with moisture and oil mixed in the chamber unit  76 , the temperature sensor  73  is held above by tilting up, and thus, it is possible to prevent the temperature sensor  73  from being damaged or the like due to moisture, oil, and the like. 
     The present embodiment can achieve advantageous effects as follows. 
     (1) The engine  2  is a V-type multi-cylinder engine having the pair of banks RB 1  and LB 1  ( FIGS.  2  and  3   ). The engine  2  includes the air intake silencer  70  that forms an air intake passage through which air is introduced from the outside, the pair of throttle bodies  71  that adjust an amount of intake air introduced via the air intake passage and sucked into each of the pair of banks RB 1  and LB 1 , and the single temperature sensor  73  that detects temperature of the air in the air intake passage ( FIGS.  3  and  6   ). The air intake silencer  70  has the pair of opening parts  77   a  on the downstream side in the air flow ( FIGS.  5  to  7   ). Each of the pair of throttle bodies  71  is connected to each of the pair of opening parts  77   a  ( FIG.  6   ). The temperature sensor  73  is disposed between the pair of opening parts  77   a  ( FIG.  6   ). This configuration makes it possible to suppress an error between the intake air temperature of each of the banks RB 1  and LB 1  and the intake air temperature detected by the temperature sensor  73 . 
     If an error occurs between the actual intake air temperature and the intake air temperature detected by the temperature sensor  73 , the fuel injection amount cannot be appropriately controlled. That is, the fuel hardly vaporizes when the intake air temperature is low, and easily vaporizes when the intake air temperature is high. Therefore, the fuel injection amount is controlled such that the air-fuel ratio of the air-fuel mixture becomes optimized in consideration of the intake air temperature. When an error occurs between the actual intake air temperature and the intake air temperature detected by the temperature sensor  73 , the fuel injection amount cannot be appropriately controlled, fuel consumption deteriorates, and emission purification efficiency deteriorates. 
     By disposing the temperature sensor  73  between the pair of opening parts  77   a , it becomes possible to detect the intake air temperature immediately before being distributed to the pair of throttle bodies  71 , and it is possible to reduce an error between the intake air temperature of each of the banks RB 1  and LB 1  and the temperature detected by the temperature sensor  73 . This makes it possible to appropriately control the fuel injection amount, and to improve the fuel consumption performance and the emission purification performance of the engine  2 . 
     When each of the pair of temperature sensors is disposed in a flow passage connected to each of the pair of throttle bodies  71 , there is a risk that the temperature sensor is positioned near a joint between the air intake silencer  70  and the engine body  2   a . When the temperature sensor is moved away from such joint, the temperature sensor is also moved away from the throttle body  71 , and an error occurs between the actual intake air temperature adjusted by the throttle body  71  and the intake air temperature detected by the temperature sensor, or vibration of the temperature sensor, noise accompanying the vibration, or the like occurs. These problems do not occur in the arrangement of the temperature sensor  73  according to the present embodiment. 
     (2) The temperature sensor  73  is disposed at a substantially equal distance from each of the pair of opening parts  77   a  ( FIG.  6   ). This configuration makes it possible to further reduce an error between the intake air temperature of each of the banks RB 1  and LB 1  and the temperature detected by the temperature sensor  73 . 
     (3) The temperature sensor  73  includes the sensor unit  73   a  that detects the temperature of air and the coupler portion  73   b  that holds the sensor unit  73   a  in the air intake passage ( FIG.  6   ). The air intake silencer  70  includes the pair of cylindrical parts  77   b  extending downstream in the flow of air from each of the pair of opening parts  77   a  ( FIGS.  4  to  7   ). The coupler portion  73   b  is fixed to the air intake silencer  70  from the outside between the pair of cylindrical parts  77   b  ( FIG.  6   ). The temperature sensor  73  penetrates the air intake silencer  70  ( FIG.  6   ). This configuration causes the coupler portion  73   b  to be disposed in the idle space between the pair of cylindrical parts  77   b , and enables the engine  2  to be downsized. 
     (4) The engine  2  includes the recirculation chamber unit  79  connected to the pair of cylindrical parts  77   b  from between the pair of cylindrical parts  77   b  and recirculates the blow-by gas from the engine body  2   a  to the air intake passage ( FIGS.  4  to  7   ). This configuration causes the recirculation chamber unit  79  and the coupler portion  73   b  to be disposed in the idle space between the pair of cylindrical parts  77   b , and enables the engine  2  to be downsized. 
     (5) The outboard motor  1  includes the engine  2  and the propeller  23  that is driven by the engine  2  to rotate ( FIGS.  1  and  2   ). This configuration makes it possible to suppress an error between the intake air temperature of each of the banks RB 1  and LB 1  and the intake air temperature detected by the temperature sensor  73 , to appropriately control the fuel injection amount, and to improve the fuel consumption performance and the emission purification performance, also in the engine  2  of the outboard motor  1 . 
     (6) The outboard motor  1  is attached to the stern of the boat  100  ( FIGS.  1  and  2   ). The pair of opening parts  77   a  are disposed on the bow side of the boat  100  relative to the pair of throttle bodies  71  with the outboard motor  1  tilted down ( FIG.  6   ). The temperature sensor  73  includes the sensor unit  73   a  that detects the temperature of air and the coupler portion  73   b  that holds the sensor unit  73   a  in the air intake passage ( FIG.  6   ). The coupler portion  73   b  is fixed to the air intake silencer  70  from the outside toward the bow side from the stern side of the boat  100  with the outboard motor  1  tilted down ( FIG.  6   ). The temperature sensor  73  penetrates the air intake silencer  70  ( FIG.  6   ). The sensor unit  73   a  extends in the horizontal direction from the coupler portion  73   b  toward the bow side from the stern side of the boat  100  with the outboard motor  1  tilted down ( FIG.  6   ). Since this configuration makes it possible to hold the temperature sensor  73  above when the outboard motor  1  is tilted up, it is possible to suppress the influence of water on the temperature sensor  73 . 
     (7) The outboard motor  1  is attached to the stern of the boat  100  ( FIGS.  1  and  2   ). The pair of opening parts  77   a  are disposed on the bow side of the boat  100  relative to the pair of throttle bodies  71  with the outboard motor  1  tilted down ( FIG.  6   ). The temperature sensor  73  includes the sensor unit  73   a  that detects the temperature of air and the coupler portion  73   b  that holds the sensor unit  73   a  in the air intake passage ( FIG.  6   ). The sensor unit  73   a  extends upward from the coupler portion  73   b  with the outboard motor  1  tilted up ( FIGS.  6  and  8   ). This configuration makes it possible to suppress the influence of water on the temperature sensor  73 . 
     (8) The boat  100  includes the outboard motor  1  and the hull  101  to which the outboard motor  1  is attached ( FIG.  1   ). This configuration makes it possible to suppress an error between the intake air temperature of each of the banks RB 1  and LB 1  and the intake air temperature detected by the temperature sensor  73 , to appropriately control the fuel injection amount, and to improve the fuel consumption performance and the emission purification performance, also in the engine  2  of the outboard motor  1  mounted on the boat  100 . 
     In the above embodiment, the description has been given using the dividable air intake silencer  70  including the silencer body  74 , the first cover  75   a  covering the exhaust heat unit  75 , and the second cover  76   a  covering the chamber unit  76 . However, the air intake silencer may be undividable with the first cover  75   a  and the second cover  76   a  integrally molded with the silencer body  74 . 
     In the above embodiment, the V-type six-cylinder engine has been described, but the present invention is not limited thereto. The present invention is preferably used for a V-type multi-cylinder engine. 
     The above embodiment can be combined as desired with one or more of the above modifications. The modifications can also be combined with one another. 
     According to the present invention, it is possible to reduce an error between an intake air temperature of air sucked from the two throttle bodies and a detection temperature that is a detected temperature of the air sucked into the throttle body. 
     Above, while the present invention has been described with reference to the preferred embodiments thereof, it will be understood, by those skilled in the art, that various changes and modifications may be made thereto without departing from the scope of the appended claims.