Motorcycle Intake System Injector Placement

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Solution Overview

Problem

Underbone type motorcycles face challenges in enhancing engine output and fuel efficiency due to the complex geometry of the intake pipe and injector placement, which restricts airflow and fuel direction, making it difficult to straddle the motorcycle while maintaining easy mounting and dismounting.

Innovation Solution

The design includes a concave region behind the head pipe and above the main frame, with a throttle body and injector placement that allows the injector to be positioned more forward than the throttle body, reducing the need for significant bending of the intake pipe, improving airflow and fuel direction towards the combustion chamber, and utilizing a shorter first intake pipe to enhance intake efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the intake pipe is significantly bent to connect the injector to the combustion chamber, then the injector can be positioned to direct fuel toward the combustion chamber, but air flow through the intake pipe becomes difficult and intake efficiency decreases

Engineering Contradiction:
Improvefuel efficiencyVSAvoidintake efficiency
Core Design Contradiction:
Use of energy by moving objectVSProductivity

Solution Approach 1:

The patent repositions the injector from a rearward location to a forward location on the throttle body, changing the spatial dimension of component arrangement. This dimensional shift allows the intake pipe to connect components in a more linear fashion, reducing bends and improving airflow while maintaining fuel injection effectiveness toward the combustion chamber

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

2Ease of operation

If the main frame is located at a low position to allow easy mounting and dismounting, then rider accessibility is improved, but the degree of freedom for installation positions of the injector and throttle body is reduced

Engineering Contradiction:
Improveease of mounting and dismountingVSAvoiddegree of freedom for installation positions
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent applies local quality by specifically positioning the injector at the forward end of the throttle body, creating a localized optimization point. This focused arrangement allows the intake system to achieve better airflow characteristics without requiring changes to the overall low main frame configuration, thus maintaining ease of mounting and dismounting while improving engine performance

Inventive Principle:
Principle #3Local quality

3Volume of moving object

If the injector is positioned rearward on the throttle body, then installation space is reduced, but the injection direction cannot be effectively directed toward the combustion chamber

Engineering Contradiction:
Improveinstallation spaceVSAvoidfuel efficiency
Core Design Contradiction:
Volume of moving objectVSUse of energy by moving object

Solution Approach 1:

The patent inverts the conventional rearward injector positioning by placing the injector at the forward end of the throttle body. This inversion allows the intake pipe to connect more directly from the air cleaner through the throttle body to the combustion chamber, reducing pipe bends and improving airflow. The forward positioning also enables better fuel injection direction toward the combustion chamber while maintaining compact installation space

Inventive Principle:
Principle #13The other way round (Inversion)

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 improves fuel efficiency and engine output while allowing riders to easily mount and dismount the motorcycle by maintaining a low concave region and optimizing the placement of components for better airflow and fuel injection.

Implementation Method 1

an injector for injecting fuel toward the intake port

Methodology Applied
Scientific EffectFuel injection: Injector

Implementation Method 2

a throttle body connected to the first intake pipe and incorporating a throttle valve

Methodology Applied
Scientific EffectThrottle valve control: Valve

Data Source

PatentEP2650528B1Motorcycle
Publication Date: 2014.11.19 YAMAHA MOTOR CO LTD
  • EP2650528B1 patent drawingFigure 1
  • EP2650528B1 patent drawingFigure 2
  • EP2650528B1 patent drawingFigure 3

AI summary

When a motorcycle 1 is viewed laterally, a concave region 12 is formed rearward of a head pipe 3, forward of a seat 9 and above a main frame 4. A throttle body 44 is provided at its lower end portion with a lower connection opening 44a connected to a first intake pipe 42, and is provided at its upper end portion with an upper connection opening 44b connected to a second intake pipe 46. When viewed from above the motorcycle 1, the upper connection opening 44b, the lower connection opening 44a and an intake port 25 at least partially overlap with each other. An injector 50 is attached to a front portion of the throttle body 44.