Outboard motor and vessel
An outboard motor includes an engine, a pressure charger, an intercooler, a bypass air passage, and an air bypass valve to open and close the bypass air passage. The engine includes a cylinder block and an air intake passage and an exhaust passage both of which are connected to the cylinder block. The pressure charger is located in the air intake passage. The intercooler is located in the air intake passage between the cylinder block and the pressure charger. A first end of the bypass air passage is connected to a region of the air intake passage upstream of the pressure charger. A second end of the bypass air passage is connected to a region of the air intake passage downstream of the pressure charger. The air bypass valve is directly attached to the intercooler.
1. An outboard motor comprising:
an engine including a cylinder block, an air intake passage connected to the cylinder block, an exhaust passage connected to the cylinder block, and a crankshaft extending along a vertical direction in the cylinder block;
a propeller to be driven by the engine;
a drive shaft joined to the crankshaft and extending along the vertical direction;
a propeller shaft extending in a horizontal direction and joined to the propeller;
a first transmission to transmit rotation of the drive shaft to the propeller shaft;
a pressure charger in the air intake passage to compress air flowing through the air intake passage;
an intercooler in the air intake passage between the cylinder block and the pressure charger to cool air compressed by the pressure charger;
a bypass air passage that bypasses the pressure charger and includes a first end connected to a region of the air intake passage located upstream of the pressure charger and a second end connected to a region of the air intake passage located downstream of the pressure charger; and
an air bypass valve directly attached to the intercooler to open and close the bypass air passage.
2. The outboard motor according to claim 1 , wherein the second end of the bypass air passage is connected to the intercooler, and the bypass air passage includes a return passage to return a portion of air guided to the intercooler to a region of the air intake passage located upstream of the pressure charger.
3. The outboard motor according to claim 1 , wherein
the intercooler includes a housing provided with a female screw;
the air bypass valve includes an insertion hole; and
the air bypass valve is directly attached to the intercooler by a bolt inserted through the insertion hole and into the female screw.
4. The outboard motor according to claim 3 , wherein
the intercooler is located laterally of the cylinder block; and
a projection projecting toward the cylinder block to reinforce the intercooler is located at a portion of the housing to which the air bypass valve is connected.
5. The outboard motor according to claim 1 , wherein the pressure charger includes a supercharger to be driven by rotation of the crankshaft.
6. The outboard motor according to claim 5 , further comprising a second transmission to join the crankshaft and the supercharger together so that the supercharger always operates while the crankshaft is rotating.
7. The outboard motor according to claim 1 , wherein the pressure charger includes a turbocharger to be driven by an exhaust gas passing through the exhaust passage.
8. The outboard motor according to claim 1 , wherein the cylinder block includes a plurality of cylinders spaced apart along the vertical direction.
9. An outboard motor comprising:
an engine including a cylinder block, an air intake passage connected to the cylinder block, an exhaust passage connected to the cylinder block, and a crankshaft located in the cylinder block;
a propeller to be driven by the engine;
a pressure charger in the air intake passage to compress air flowing through the air intake passage;
an intercooler in the air intake passage between the cylinder block and the pressure charger to cool air compressed by the pressure charger;
a bypass air passage to bypass the pressure charger and including a first end connected to a region of the air intake passage upstream of the pressure charger and a second end connected to a region of the air intake passage downstream of the pressure charger; and
an air bypass valve directly attached to the intercooler to open and close the bypass air passage.
10. A vessel comprising:
a hull; and
the outboard motor according to claim 1 on the hull.