Outboard Motor Fuel Injector and Spark Plug Layout

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Solution Overview

Problem

In outboard motors with internal combustion engines, the conventional placement of fuel injectors and spark plugs leads to interference with other components, increasing the size of the motor and making it difficult to align multiple motors side-by-side due to constraints on the shape and layout of valve actuators, which hampers efficient combustion and fuel distribution.

Innovation Solution

The fuel injector and spark plug are strategically positioned in the central region of the combustion chamber, with the spark plug offset from the fuel injector and inclined to avoid interference with valve actuators, allowing for uniform air-fuel mixture distribution and ignition, reducing the motor's size and improving combustion efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the fuel injector is disposed below the intake valve to avoid interference with other members, then the outboard motor size increases and multiple motors cannot be disposed side-by-side, but if the fuel injector is disposed near the center of the combustion chamber to reduce size, then the fuel injector and spark plug interfere with each other and with the valve actuator

Engineering Contradiction:
Improveoutboard motor sizeVSAvoidinterference between components
Core Design Contradiction:
Volume of moving objectVSObject-generated harmful factors

Solution Approach 1:

The spark plug is disposed to extend along the axial direction of the cylinder rather than radially, changing the spatial dimension of component arrangement. This allows the spark plug and fuel injector to be positioned near the center of the combustion chamber without interfering with each other, as they occupy different spatial dimensions and orientations

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The spark plug and fuel injector are positioned asymmetrically relative to the combustion chamber center, with the spark plug extending axially and the fuel injector positioned at a specific angle. This asymmetric arrangement optimizes combustion efficiency while preventing interference with valve actuators and other components

Inventive Principle:
Principle #4Asymmetry

2Object-generated harmful factors

If the fuel injector is disposed below the intake valve, then interference with other members is reduced, but the protrusion of the intake pipe must be increased, increasing the overall width of the outboard motor

Engineering Contradiction:
Improveinterference between intake port and fuel injectorVSAvoidintake pipe protrusion and motor width
Core Design Contradiction:
Object-generated harmful factorsVSLength of moving object

Solution Approach 1:

The fuel injector is positioned near the center of the combustion chamber rather than below the intake valve, changing the spatial location to avoid interference with the intake pipe. This eliminates the need for increased intake pipe protrusion and reduces the overall motor width

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The fuel injector is specifically positioned in the central region of the combustion chamber where it can effectively inject fuel without interfering with surrounding components. This localized positioning optimizes both combustion performance and spatial efficiency

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If the fuel injector and spark plug are disposed near the center of the combustion chamber to reduce motor size, then constraints on valve actuator layout are reduced, but the fuel injector and spark plug interfere with each other and with the valve actuator

Engineering Contradiction:
Improvevalve actuator shape and layout flexibilityVSAvoidinterference between fuel injector, spark plug, and valve actuator
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The spark plug is oriented to extend along the axial direction of the cylinder, utilizing the vertical dimension rather than radial space. This dimensional change allows the spark plug to be positioned near the combustion chamber center without interfering with horizontally positioned valve actuators

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The combustion chamber is functionally segmented into different zones: the fuel injector occupies the central injection zone, the spark plug occupies the axial ignition zone, and the valve actuators occupy the peripheral actuation zone. This segmentation allows all components to be positioned near the center without interference

Inventive Principle:
Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration enhances combustion efficiency by ensuring a uniform flame front and reduces mechanical constraints, allowing for more compact motor design and easier alignment of multiple motors.

Implementation Method 1

a fuel injector (50) including a fuel injection portion (51) configured to inject fuel from a central region (C1) of the combustion chamber (C) between the intake opening (22a) and the exhaust opening (23a) into the combustion chamber (C)

Methodology Applied
Scientific EffectFuel injection: Injector

Implementation Method 2

a spark plug (60) including an ignition portion (61) located to be offset in the direction of the camshaft (32) with respect to the fuel injection portion (51) in the central region (C1) of the combustion chamber (C) and configured to provide ignition within the combustion chamber (C)

Methodology Applied
Scientific EffectElectrical discharge: Electric Spark

Implementation Method 3

an internal combustion engine (1) including a cylinder head (20) including an intake opening (22a) through which intake air is introduced into a combustion chamber (C) of a cylinder (10a) and an exhaust opening (23a) through which exhaust gas is discharged from the combustion chamber (C)

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP3354875B1Outboard motor
Publication Date: 2019.10.09 YAMAHA MOTOR CO LTD
  • EP3354875B1 patent drawingFigure 1
  • EP3354875B1 patent drawingFigure 2
  • EP3354875B1 patent drawingFigure 3~4

AI summary

An outboard motor (100) includes an internal combustion engine (1). The internal combustion engine includes a fuel injector (50) including an injection portion (51) and mounted in a cylinder head (20), and an ignition (60) including an ignition portion (61) deviated in an upward-downward direction in which a valve actuating shaft (32) extends with respect to the injection portion in a central region (C1) and configured to provide ignition within a combustion chamber (C), the ignition mounted in the cylinder head.