Engine for outboard motor

Patent metadata

Field	Value
Publication number	US-2016368580-A1
Application number	US-201615180777-A
Country	US
Kind code	A1
Filing date	Jun 13, 2016
Priority date	Jun 16, 2015
Publication date	Dec 22, 2016
Grant date	—

Abstract

An engine for an outboard motor is provided with an engine body, an intake system configured to supply combustion air to the engine body, an exhaust passage formed by connecting the engine body and middle and lower units thereunder, a catalyst provided in the exhaust passage, and an air pump configured to supply secondary air to an upstream side of the catalyst. The intake system is arranged in a side portion of one side of the left or right side of the engine body, and the exhaust passage and the air pump are arranged in a side portion of the other side of the left or right side of the engine body.

First claim

What is claimed is:

1 . An engine for an outboard motor comprising:
an in-line multiple-cylinder engine body provided with a crankshaft having an axial line directed to a vertical direction and a plurality of vertically overlapping cylinders, the cylinders having axial lines directed backward in a horizontal direction; an intake system configured to supply combustion air to the engine body; an exhaust passage formed to connect the engine body and middle and lower units thereunder; a catalyst provided in the exhaust passage; and an air pump configured to supply secondary air to an upstream side of the catalyst in the exhaust passage, wherein the intake system is arranged in a side portion of one side of the left or right side of the engine body, and the exhaust passage and the air pump are arranged in a side portion of the other side of the left or right side of the engine body.

2 . The engine for an outboard motor according to claim 1 , wherein the exhaust passage has
an exhaust manifold that is connected to exhaust ports provided in each cylinder of the engine body and extends in a vertical direction, a catalyst housing portion arranged in parallel with the exhaust manifold to house the catalyst, and a connection passage configured to connect the exhaust manifold and the catalyst housing portion,
the air pump is arranged in a front side of the engine body relative to the exhaust manifold and the catalyst housing portion, and
a connecting portion for connection from the air pump to the secondary air supply passage is provided in any one of the exhaust ports of each cylinder, the exhaust manifold, and the connection passage and is connected to the secondary air supply passage in an upstream side relative to the catalyst housing portion in an exhaust flow direction.

3 . The engine for an outboard motor according to claim 2 , wherein the catalyst housing portion is arranged in a rear side of the engine body relative to the exhaust manifold.

4 . The engine for an outboard motor according to claim 1 , wherein the air pump is connected to the crankshaft by interposing a power transmission device and is driven by the crankshaft, and
the power transmission device has a clutch mechanism capable of controlling transmission of a driving force.

5 . The engine for an outboard motor according to claim 2 , wherein the connecting portion of the secondary air supply passage is formed integrally with the cylinder block included in the engine body and is provided with a communicating passage communicating with each exhaust port of each cylinder.

6 . The engine for an outboard motor according to claim 2 , wherein a connecting portion of the exhaust passage for connection to the secondary air supply passage is formed in the most upstream side of the exhaust manifold in the exhaust flow direction.

7 . The engine for an outboard motor according to claim 2 , wherein the connection passage for connecting the exhaust manifold of the exhaust passage and the catalyst housing portion has an upright portion that extends upward from a lower part of the exhaust manifold and is connected to a top portion of the catalyst housing portion, and
a connecting portion for connection to the secondary air supply passage is formed approximately in the most upstream side of the connection passage in the exhaust flow direction.

8 . The engine for an outboard motor according to claim 1 , wherein the engine body and the intake and exhaust systems thereof are housed in an engine housing covered by an engine cover,
an opening of an external air guide unit for receiving external air to the inside of the engine housing is provided behind the engine body in a rear part of the engine housing, and an inlet port of the air pump is set vertically higher than an opening of the external air guide unit in a front part of the engine housing.

Assignees

• Suzuki Motor Corp

Inventors

• Shomura Nobuyuki
• Hayashi Toshio
• Miyaki Tomohiko
• Hamada Ryuji

Classifications

• F01N2590/021

  for outboard engines · CPC title

• F01N2550/14

  Systems for adding secondary air into exhaust · CPC title

• B63H20/24 Primary

  Arrangements, apparatus and methods for handling exhaust gas in outboard drives, e.g.} exhaust gas outlets {(in engines, e.g. outboard marine engines, F01N) · CPC title

• B63H23/30

  characterised by use of clutches · CPC title

• B63H20/001

  Arrangements, apparatus and methods for handling fluids used in outboard drives (for handling exhaust gas B63H20/24; for handling cooling-water B63H20/28; cooling outboard marine engines F01P3/202; air intakes for outboard marine engines F02M35/167) · CPC title