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.
This invention relates to an engine, an outboard motor, and a boat.
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.
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.
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:
An embodiment of the present invention will be described below with reference to
As illustrated in
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 2b. 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 22a 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 21a and a backward bevel gear 21b that are connected to the drive shaft 20 and rotate, a clutch 21c that engages the propeller shaft 22 with either the forward bevel gear 21a or the backward bevel gear 21b, a shift rod 21d, and a shift slider 21e. 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 21d via a reduction gear mechanism 25, and the shift slider 21e is connected to the lower end of the shift rod 21d.
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 21d and the shift slider 21e are appropriately displaced to operate the clutch 21c, 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.
The engine 2 includes an engine body 2a having a first bank RB1 and a second bank LB1, an air intake device 7 provided above the engine body 2a, a mount case 8 provided below the engine body 2a, and an oil pan 9 provided below the mount case 8.
The engine body 2a 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 RB1 and LB1 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 RB1 and the second bank LB1. 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 (
The mount case 8 is interposed between the engine body 2a and the oil pan 9, and supports the engine body 2a. 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 2a. 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 2c formed in the engine cover 2b 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 RB1 and LB1. 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 75a covering the exhaust heat unit 75, and a second cover 76a covering the chamber unit 76. The first cover 75a covers the exhaust heat unit 75 via a seal member 75b, thereby forming an exhaust heat space. The second cover 76a 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 76b, thereby forming an air intake space (air intake passage).
The exhaust heat unit 75 is provided with an exhaust fan (not illustrated), and the heat of the engine body 2a is introduced into the exhaust heat space via this exhaust fan. The air flowing in from the air introduction portion 2c of the engine cover 2b is guided to the chamber unit 76 and introduced into the air intake passage. Specifically, the air flowing in from the air introduction portion 2c is guided in the vertical direction by a descending flow path (arrow A in
One end of each of the pair of throttle bodies 71 is connected to each of the pair of left and right cylindrical parts 77b formed in the chamber unit 76 via the grommet 71b, and the other end is connected to the intake manifold 72. Each of the pair of throttle bodies 71 has a throttle valve 71a 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 RB1 and LB1 is adjusted by adjusting the opening of the throttle valve 71a.
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 RB1 and LB1. 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 RB1 and LB1 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 71a. 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 73a that detects temperature and a coupler portion 73b that fixes the sensor unit 73a, and the sensor unit 73a 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 RB1 and LB1 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 77a 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 RB1 and LB1 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.
The sensor attachment portion 78 is configured to be able to be attached with the coupler portion 73b in a state where the sensor unit 73a is inserted from the rear such that the sensor unit 73a 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 73a is positioned in the air intake passage in a state of being substantially parallel to the front-rear direction, and the coupler portion 73b is positioned in an idle space between the pair of cylindrical parts 77b. 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 2a (the gas chamber of the cylinder head cover 6).
As illustrated in
The recirculation chamber unit 79 includes a chamber unit body 79a into which the blow-by gas flows, a connection portion 79b to which the breather tube 61 is connected, and a pair of communication portions 79c communicating with the chamber unit body 79a and the pair of cylindrical parts 77b. The chamber unit body 79a is formed in a groove shape in the silencer body 74, and constitutes a recirculation passage by attaching the member 74b to the silencer body 74. The shape and size of the chamber unit body 79a are not limited thereto, and can be appropriately changed. The connection portion 79b is provided in the member 74b and communicates the recirculation passage of the chamber unit body 79a and the space inside the tube of the breather tube 61. The connection portion 79b is provided to protrude upward from the member 74b, and is configured to cover the connection portion 79b with the tip of the breather tube 61 so that the breather tube 61 is attached. Each of the pair of communication portions 79c allows the internal space of each of the pair of cylindrical parts 77b to communicate with the recirculation passage of the chamber unit body 79a.
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 RB1 and LB1 (
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 77a, 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 RB1 and LB1 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 2a. 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 77a (
(3) The temperature sensor 73 includes the sensor unit 73a that detects the temperature of air and the coupler portion 73b that holds the sensor unit 73a in the air intake passage (
(4) The engine 2 includes the recirculation chamber unit 79 connected to the pair of cylindrical parts 77b from between the pair of cylindrical parts 77b and recirculates the blow-by gas from the engine body 2a to the air intake passage (
(5) The outboard motor 1 includes the engine 2 and the propeller 23 that is driven by the engine 2 to rotate (
(6) The outboard motor 1 is attached to the stern of the boat 100 (
(7) The outboard motor 1 is attached to the stern of the boat 100 (
(8) The boat 100 includes the outboard motor 1 and the hull 101 to which the outboard motor 1 is attached (
In the above embodiment, the description has been given using the dividable air intake silencer 70 including the silencer body 74, the first cover 75a covering the exhaust heat unit 75, and the second cover 76a covering the chamber unit 76. However, the air intake silencer may be undividable with the first cover 75a and the second cover 76a 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.
Number | Date | Country | Kind |
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2021-032849 | Mar 2021 | JP | national |