Motorcycle Cooling System Layout for Compact Width and Aesthetics

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Solution Overview

Problem

Existing cooling system structures for small-sized vehicles, such as motorcycles, face challenges in minimizing the size of the power unit in the vehicle width direction and reducing piping length, while maintaining an aesthetically pleasing appearance, due to the positioning of the water pump and thermostat.

Innovation Solution

The water pump is positioned rearwardly to sandwich the cylinder section between itself and the radiator, with a discharge port connected to one water jacket and a suction port connected to another, allowing for shorter piping lengths and improved routing of pipes, and the thermostat is mounted on the front wall surface to select communication conditions between water jackets directly or via the radiator.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the water pump is disposed on the side wall of the cylinder body, then the positioning is less likely to be subject to restrictions in terms of layout, but the power unit size increases in the vehicle width direction and the piping length becomes longer

Engineering Contradiction:
Improvelayout flexibilityVSAvoidpower unit size
Core Design Contradiction:
Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The water pump is repositioned from a lateral arrangement (vehicle width direction) to a longitudinal arrangement along the vehicle length direction. Specifically, the water pump is disposed at the rear of the cylinder body in the longitudinal direction, changing the spatial dimension of installation from width to length, thereby reducing the power unit width while maintaining layout flexibility through the longitudinal piping route

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

2Reliability

If external pipes are disposed on both sides of the engine main unit to connect the thermostat and radiator, then the cooling system functions, but the appearance is degraded

Engineering Contradiction:
Improvecooling system functionVSAvoidappearance
Core Design Contradiction:
ReliabilityVSShape

Solution Approach 1:

The piping routes are merged and consolidated to pass through the central longitudinal space of the engine main unit rather than extending externally on both sides. The discharge port connects to one water jacket and the suction port to another through centrally routed pipes, eliminating the need for external side pipes and improving appearance while maintaining cooling functionality

Inventive Principle:
Principle #5Merging (Combining)

3Length of stationary object

If the water pump is disposed forwardly of the cylinder body, then the piping length to the radiator is reduced, but the power unit size increases in the vehicle width direction

Engineering Contradiction:
Improvepiping lengthVSAvoidpower unit size
Core Design Contradiction:
Length of stationary objectVSVolume of moving object

Solution Approach 1:

Instead of reducing piping length by moving the water pump forward in the width direction, the solution moves the water pump rearward in the longitudinal direction. This dimensional shift allows the pipes to route centrally along the length of the engine, achieving compact width dimensions while maintaining reasonable piping lengths through the longitudinal axis

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

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 reduces the size of the power unit in the vehicle width direction, shortens piping lengths, and improves the appearance by allowing pipes to be routed more centrally, enhancing the overall cooling system efficiency and aesthetics.

Implementation Method 1

a water pump disposed on an engine main unit to perform a forced circulation of coolant through a radiator and water jackets

Methodology Applied
Scientific EffectForced Convection: Forced Convection

Implementation Method 2

A radiator is disposed forwardly of the engine main unit with a water pump disposed on the engine main unit. The water pump performs a forced circulation of coolant through the radiator and the water jackets.

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP2644861B1Motorcycle with a cooling system structure and a water-cooled internal combustion engine
Publication Date: 2016.05.18 HONDA MOTOR CO LTD
  • EP2644861B1 patent drawingFigure 1
  • EP2644861B1 patent drawingFigure 2
  • EP2644861B1 patent drawingFigure 3

AI summary

In a cooling system structure for a vehicular water-cooled internal combustion engine (E) with a cylinder section and a cylinder body (41) and a cylinder head (42). The cooling system structure having water jackets (50A) formed in the cylinder body (41) and the cylinder head (42), respectively, with a radiator (52) disposed forwardly of the engine main unit. A water pump performs forced circulation of coolant through the radiator (52) and the water jackets (50A), to permit routing of pipes with enhanced appearance. Water jackets (50A) are formed, respectively, in a cylinder body (41) and a cylinder head (42) such that coolant flows through the cylinder body (42) and the cylinder head (42) independently of each other. A thermostat is mounted on a front wall surface of a cylinder section and is capable of selecting a condition in which the water jackets (50A) directly communicate with each other or a condition in which the water jackets (50A) communicate with each other via a radiator (52).