# US 6,296,536 B1 · Cowling assembly for outboard motor

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- Number: US 6,296,536 B1
- Document ID: US6296536B1
- Status: Granted
- Kind: B1
- Application number: 09/559,863
- Filed: 2000-04-27
- Granted: 2001-10-02
- Earliest claimed: 1999-04-27
- Assignees: Sanshin Kogyo Kabushiki Kaisha
- Inventors: Goichi Katayama; Takaji Kawai; Masanori Takahashi; Hitoshi Ishida
- Web page: https://patentgrep.com/patent/US6296536B1

## CPC

- F02M 35/167: {having outboard engines; Jet-skis}
- B63H 20/32: Housings {(air intakes for outboard engines F02M35/167)}
- F02B 75/20: with cylinders all in one line
- F02M 35/10039: {Intake ducts situated partly within or on the plenum chamber housing}
- F02M 35/116: for engines with cylinders in V-arrangement or arranged oppositely relative to the main shaft
- F02B 61/045: {for marine engines}
- F02B 2075/027: {four}
- F02B 2075/1816: {four}
- F02B 2275/18: DOHC [Double overhead camshaft]
- F02M: SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- B63H: MARINE PROPULSION OR STEERING (propulsion of air-cushion vehicles B60V1/14; specially adapted for submarines, other than nuclear propulsion, B63G; specially adapted for torpedoes F42B19/00)
- F02B: INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL (gas-turbine plants F02C; hot-gas or combustion-product positive-displacement engine plants F02G)

## Abstract

A cowling assembly for an outboard motor includes an improved construction that can supply relatively cool air containing little if no water to the induction device and that can also supply air to cool engine components without reducing the charging efficiency. The outboard motor has an engine that includes an air induction device and is enclosed by the cowling. The induction device has an air inlet opening. The cowling assembly defines a closed cavity in which the engine is contained and has an air intake duct that introduces air into the cavity. The intake duct adjoins the inlet opening and has an opening opened to the cavity and positioned lower than a lower end of the inlet opening. In one form, the cowling assembly has at least one front air intake opening formed on a side surface of its front portion. A rear air intake opening is also formed on a rear surface of its rear end portion. The cowling front air opening primarily supplies air to the induction system, while the cowling rear air opening primarily supplies a cooling air flow across the engine.

## Claims

### Claim 1

An outboard motor comprising an internal combustion engine including an air induction device, the air induction device defining an air inlet opening, and a cowling assembly including a cowling member defining a generally closed first cavity that contains the engine, an air intake duct introducing ambient air into the first cavity, the air intake duct arranged adjacent to the air inlet opening, the intake duct opening into the first cavity at a location generally lower than a lower end of the air inlet opening of the air induction device, and a shell member defining a second cavity together with the cowling member, the intake duct coupling the second cavity with the first cavity.

### Claim 2 (depends on 1)

An outboard motor as set forth in claim 1, wherein the cowling member defines a step-like portion, and the intake duct is disposed at the step-like portion.

### Claim 3 (depends on 2)

An outboard motor as set forth in claim 2, wherein the intake duct includes an upper portion extending generally above the step-like portion and a lower portion extending below the step-like portion.

### Claim 4 (depends on 3)

An outboard motor as set forth in claim 3, wherein the lower portion has a cutout that does not face to the inlet opening.

### Claim 5 (depends on 2)

An outboard motor as set forth in claim 2, wherein the intake duct is provided separately from the step-like portion and is coupled thereto.

### Claim 6 (depends on 2)

An outboard motor as set forth in claim 2, wherein an inner member defining the step-like portion is provided separately from the cowling member and is affixed onto an inner surface of the cowling member to define a second cavity therebetween.

### Claim 7 (depends on 6)

An outboard motor as set forth in claim 6, wherein the cowling member defines an air intake opening through which ambient air is introduced into the second cavity.

### Claim 8 (depends on 1)

An outboard motor as set forth in claim 1, wherein the shell member defines at least one air intake opening through which ambient air is introduced into the second cavity.

### Claim 9 (depends on 8)

An outboard motor as set forth in claim 8, wherein the air intake opening is defined between the shell member and the cowling member.

### Claim 10 (depends on 9)

An outboard motor as set forth in claim 9, wherein the shell member has at least one projection extending toward the cowling member.

### Claim 11 (depends on 8)

An outboard motor as set forth in claim 8, wherein the air intake opening is defined within the shell member.

### Claim 12 (depends on 8)

An outboard motor as set forth in claim 8, wherein the intake opening exists higher than the lower end of the inlet opening.

### Claim 13 (depends on 8)

An outboard motor as set forth in claim 8, wherein the shell member defines the air intake opening on its side surface.

### Claim 14 (depends on 1)

An outboard motor as set forth in claim 1, wherein the shell member defines the second cavity with a front portion of the cowling member.

### Claim 15 (depends on 14)

An outboard motor as set forth in claim 14, wherein the shell member defines an air intake opening on its side surface through which ambient air is introduced into the second cavity.

### Claim 16 (depends on 14)

An outboard motor as set forth in claim 14, wherein the cowling member defines a second air intake opening on its rear surface.

### Claim 17 (depends on 1)

An outboard motor as set forth in claim 1, wherein the inlet opening is provided on a plenum chamber.

### Claim 18

An outboard motor comprising an internal combustion engine including an air induction device, the air induction device defining an air inlet opening, and a cowling assembly including a cowling member defining a generally closed cavity that contains the engine, and an air intake duct introducing ambient air into the cavity, the air intake duct arranged adjacent to the air inlet opening, the intake duct opening into the cavity at a location generally lower than a lower end of the air inlet opening of the air induction device, the inlet opening extending generally vertically, and the intake duct extending generally parallelly to the inlet opening.

### Claim 19

An outboard motor comprising an internal combustion engine including an air induction device, the air induction device defining an air inlet opening, and a cowling assembly including a cowling member defining a generally closed cavity that contains the engine, and an air intake duct introducing ambient air into the cavity, the air intake duct arranged adjacent to the air inlet opening, the intake duct opening into the cavity at a location generally lower than a lower end of the air inlet opening of the air induction device, the inlet opening existing generally within one half of the cavity defined by a center plane extending generally vertically, and the intake duct existing generally within the other half of the cavity.

### Claim 20 (depends on 19)

An outboard motor as set forth in claim 19, wherein the inlet opening faces toward the opposite half of the cavity in which the intake duct is disposed.

### Claim 21 (depends on 20)

An outboard motor as set forth in claim 20, wherein the inlet opening has an axis extending generally normal to the center plane.

### Claim 22

An outboard motor comprising an internal combustion engine including an air induction device, the air induction device defining an air inlet opening, and a cowling assembly including a first cowling member defining a generally closed cavity that contains the engine, an air intake duct introducing ambient air into the cavity, the air intake duct arranged adjacent to the air inlet opening, the intake duct opening into the cavity at a location generally lower than a lower end of the air inlet opening of the air induction device, and a second cowling member disposed lower than the first cowling member, both of the first and second cowling members being coupled together, and the lower end of the intake duct being positioned lower than an interface between the first and second cowling members adjacent to the intake duct.

### Claim 23

An outboard motor comprising an internal combustion engine including an air induction device, the air induction device including an air inlet opening, and a cowling assembly including a cowling member defining a generally closed cavity that contains the engine, the cowling member having at least one front air intake opening formed on a side surface of a front portion of the cowling member and a rear air intake opening formed on a rear surface of a rear portion of the cowling member, and ambient air being introduced into the cavity through both of the front and rear air intake openings and drawn into the inlet opening.

### Claim 24 (depends on 23)

An outboard motor as set forth in claim 23, wherein the cowling member has a pair of the front openings, and each front opening is located on each side surface of the front portion of the cowling member.

### Claim 25

An outboard motor comprising an internal combustion engine including an air induction device, the air induction device defining an air inlet opening, and a cowling assembly including a cowling member defining a generally closed first cavity that contains the engine, the cowling member having at least one front air intake opening formed on a side surface of a front portion of the cowling member and a rear air intake opening formed on a rear surface of a rear portion of the cowling member, a shell member defining a second cavity together with the front portion of the cowling member, ambient air being introduced through the front air intake opening into the second cavity, and an air intake duct adjoining the air inlet opening and coupling the second cavity with the first cavity, the intake duct having a lower opening positioned generally lower than a lower end of the air inlet opening.

### Claim 26

An outboard motor comprising an internal combustion engine including an air induction device, the air induction device defining an air inlet opening, and a cowling assembly including a cowling member defining a generally closed first cavity that contains the engine, the cowling member having at least one front air intake opening formed on a side surface of a front portion of the cowling member and a rear air intake opening formed on a rear surface of a rear portion of the cowling member, a shell member defining a second cavity together with the rear portion of the cowling member, ambient air being introduced through the rear air intake opening into the second cavity, an air intake duct coupling the second cavity with the first cavity, and a baffle positioned adjacent to an inlet of the air intake duct to inhibit water from entering the intake duct.

### Claim 27

An outboard motor comprising an internal combustion engine including an air induction device, the air induction device defining an air inlet opening, and a cowling assembly including a cowling member defining a generally closed first cavity that contains the engine, the cowling member having at least one front air intake opening formed on a side surface of its front portion and a rear air intake opening formed on a rear surface of a rear end portion, a shell member defining a second cavity together with the rear end portion of the cowling member, ambient air being introduced through the rear air intake opening into the second cavity, and an air intake duct coupling the second cavity with the first cavity, the air intake duct being disposed above at least a portion of the engine, and the air intake duct having a guide directing the air toward one side of the engine.

### Claim 28 (depends on 27)

An outboard motor as set forth in claim 27, wherein the inlet opening exists generally within one half of the cavity defined by a center plane extending generally vertically, and the guide leads the air toward the other half of the cavity.

### Claim 29

An outboard motor comprising an internal combustion engine including an air induction device, the air induction device defining an air inlet opening, and a cowling assembly including a cowling member defining a generally closed cavity that contains the engine, the cowling member having at least one front air intake opening formed on a side surface of a front portion of the cowling member and a rear air intake opening formed on a rear surface of a rear portion of the cowling member, and a front air intake duct adjacent to the front air intake opening, ambient air being introduced through the front air intake duct into the cavity, a rear air intake duct adjacent to the rear air intake opening, the ambient air being introduced also through the rear air intake duct into the cavity, the inlet opening existing generally within one half of the cavity defined by a center plane extending generally vertically, and the front and rear intake ducts both existing generally within the other half of the cavity.

### Claim 30

An outboard motor comprising an internal combustion engine including an air induction device, the air induction device defining an air inlet opening, and a cowling assembly including a cowling member defining a generally closed first cavity that contains the engine, the cowling member having at least one front air intake opening formed on a side surface of a front portion of the cowling member and a rear air intake opening formed on a rear surface of a rear portion of the cowling member, a shell member defining a second cavity together with the rear portion of the cowling member, ambient air is introduced through the air intake opening into the second cavity, an air intake duct coupling the second cavity with the first cavity, and a baffle positioned adjacent to an outlet of the air intake duct.

### Claim 31

An outboard motor comprising an internal combustion engine including an air induction device, the air induction device defining an air inlet opening, and a cowling assembly including a cowling member defining a generally closed cavity that contains the engine, and an air intake duct introducing ambient air into the cavity, the inlet opening extending generally vertically, and the intake duct extending generally in parallel to the inlet opening.

### Claim 32

An outboard motor comprising an internal combustion engine including an air induction device, the air induction device defining an air inlet opening, and a cowling assembly including a cowling member defining a generally closed cavity that contains the engine, and an air intake duct introducing ambient air into the cavity, the inlet opening existing generally within one half of the cavity defined by a center plane extending generally vertically, and the intake duct existing generally within the other half of the cavity.

### Claim 33 (depends on 32)

An outboard motor as set forth in claim 32, wherein the inlet opening faces toward the opposite half of the cavity in which the intake duct is disposed.

### Claim 34

An outboard motor comprising an internal combustion engine including an air induction device, the air induction device defining an air inlet opening, and a cowling assembly including a cowling member defining a first cavity that contains the engine, the cowling member having an air intake opening, a shell member defining a second cavity together with the cowling member, ambient air being introduced into the second cavity through the air intake opening, an air intake duct coupling the second cavity with the first cavity, and a baffle positioned adjacent to an inlet of the air intake duct to inhibit water from entering the intake duct.

### Claim 35

An outboard motor comprising an internal combustion engine including an air induction device, the air induction device defining an air inlet opening, and a cowling assembly including a cowling member defining a first cavity that contains the engine, the cowling member having an air intake opening, a shell member defining a second cavity together with the cowling member, ambient air being introduced through the air intake opening into the second cavity, and an air intake duct coupling the second cavity with the first cavity, the air intake duct being disposed above at least a portion of the engine, and the air intake duct having a guide directing the air toward one side of the engine.

### Claim 36 (depends on 35)

An outboard motor as set forth in claim 35, wherein the inlet opening exists generally within one half of the cavity defined by a center plane extending generally vertically, and the guideleads the air toward the other half of the cavity.

### Claim 37

An outboard motor comprising an internal combustion engine including an air induction device, the air induction device defining an air inlet opening, and a cowling assembly including a cowling member defining a first cavity that contains the engine, the cowling member having an air intake opening, a shell member defining a second cavity together with the cowling member, ambient air being introduced into the second cavity through the air intake opening, an air intake duct coupling the second cavity with the first cavity, and a baffle positioned adjacent to an outlet of the air intake duct.