Intake device for outboard motor
AssigneeYamaha Marine Kabushiki Kaisha
InventorsYoshibumi Iwata, Masanori Takahashi, Satoshi Miyazaki
Life of this patent
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Abstract
An engine air intake device for an outboard motor includes a plurality of main intake pipes corresponding to each cylinder. First and second branch pipes extend from an upstream end of each main part. The first branch pipes are longer than the second branch pipes. The second branch pipes each include a valve and are selectively closed. The first branch pipes open into a first surge tank. The second branch pipes open into a second surge tank that is formed separately from the first surge tank. In operation, the valves of the second branch pipes are open when the engine is operating in high engine speed and are closed at low-to-medium speeds.
Claims17
An intake device for an outboard motor internal combustion engine having a plurality of cylinders, the intake device comprising a plurality of main intake pipes, each main intake pipe having an upstream end and a downstream end, the downstream end communicating with a corresponding one of the cylinders, the upstream end connected to first and second branch pipes, each first branch pipe having a length greater than a length of each of the second branch pipes, each second branch pipe having a valve for selectively opening or closing the corresponding second branch pipe, a first surge tank, upstream ends of the first branch pipes opening into the first surge tank, a second surge tank formed separately from the first surge tank, upstream ends of a plurality of the second branch pipes opening into the second surge tank, each of the first and second surge tanks comprising an opening adapted to allow air to flow into the respective surge tank.
An outboard motor comprising an internal combustion engine and an air intake device generally enclosed within a cowling, the air intake device conducting air from within the cowling to a plurality of intake passages of the engine, the intake device comprising a plurality of main intake pipes, each main intake pipe comprising a downstream end communicating with a corresponding engine intake passage and comprising an upstream end, each upstream end connected to means for selectively forming a relatively long intake air path or forming a relatively short intake path, air for the long intake path being drawn from a first tank and air for the short intake path being drawn from a second tank formed separately from the first tank, means for minimizing intake interference at low/medium engine speeds and means for minimizing intake interference at high engine speeds.
Dependencies are inferred from the claim text.