Motorcycle Cooling Pipe Routing Between Exhaust and Crankcase

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Solution Overview

Problem

Motorcycles with multi-cylinder engines face limitations in bank angle during high-speed turns due to the curvature of cooling liquid pipes, which can decrease cooling efficiency and restrict turning stability.

Innovation Solution

The cooling liquid pipe is routed to pass through the space between the crankcase and exhaust pipes, curving inward to connect the radiator, allowing for a larger bank angle without significantly reducing cooling efficiency, and can be made of resin to reduce weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the cooling liquid pipe is curved outward at the front end of the crankcase to connect the radiator, then the cooling efficiency is maintained, but the bank angle is limited

Engineering Contradiction:
Improvecooling efficiencyVSAvoidbank angle
Core Design Contradiction:
TemperatureVSAdaptability or versatility

Solution Approach 1:

The cooling liquid pipe is routed through the space between the crankcase and exhaust pipes, utilizing the vertical dimension and spatial arrangement rather than curving outward horizontally. This dimensional repositioning allows the pipe to connect the radiator while clearing the exhaust pipes, thereby enabling larger bank angles without compromising cooling efficiency

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

2Adaptability or versatility

If the cooling liquid pipe is arranged in the space between the crankcase and exhaust pipes, then the bank angle is increased, but the cooling efficiency may decrease due to high temperature

Engineering Contradiction:
Improvebank angleVSAvoidcooling efficiency
Core Design Contradiction:
Adaptability or versatilityVSTemperature

Solution Approach 1:

The pipe routing through the space between the crankcase and exhaust pipes converts the previously harmful high-temperature zone into a beneficial space utilization opportunity. By carefully positioning the pipe in this gap, the design achieves larger bank angles while the pipe itself does not significantly absorb heat that would compromise cooling efficiency, as the space is naturally cooled by air flow during operation

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Weight of moving object

If the cooling liquid pipe is made of resin to reduce weight, then the overall weight is decreased, but the heat resistance may be insufficient

Engineering Contradiction:
Improvepipe weightVSAvoidheat resistance
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The patent specifies using resin material for the cooling liquid pipe, representing a parameter change from traditional metal materials. This material substitution reduces weight while the specific resin composition and pipe design maintain sufficient heat resistance for the application, balancing weight reduction with thermal performance requirements

Inventive Principle:
Principle #35Parameter changes

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 enables motorcycles to maintain high cooling efficiency and stability at larger bank angles, improving turning performance while minimizing weight.

Implementation Method 1

cooling water circulates between the engine and a radiator

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

cooling water circulates between the engine and a radiator

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

cooling water circulates between the engine and a radiator

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3009626B1motorcycle
Publication Date: 2017.08.16 YAMAHA MOTOR CO LTD
  • EP3009626B1 patent drawingFigure 1
  • EP3009626B1 patent drawingFigure 2
  • EP3009626B1 patent drawingFigure 3

AI summary

A plurality of exhaust pipes are respectively connected to a plurality of exhaust ports of a cylinder head. The plurality of exhaust pipes are arranged in a left-and-right direction to be spaced apart from one another and pass in front of and below a crankcase from the cylinder head to extend rearward. A first pipe that connects a water pump to a radiator extends forward at the right of a right side surface portion to a front surface portion of the crankcase and is curved leftward from the right of the right side surface portion in a front view of a motorcycle. Further, the first pipe passes through an inner region between a left end and a right end of the plurality of exhaust pipes to be connected to the radiator in the front view of the motorcycle.