Crank Case Cooling Water Passage Integration

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Solution Overview

Problem

Water-cooled motorcycle engines have exposed water piping and pumps, which degrade the external appearance and increase manufacturing costs.

Innovation Solution

The water pump is housed inside the crank case, with a cooling water passage formed integrally within the crank case, eliminating external exposure and simplifying the need for water pipes and hoses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If water pump and water piping are provided outside the engine, then cooling function is achieved, but external appearance is degraded and manufacturing cost increases

Engineering Contradiction:

Improvecooling functionVSAvoidexternal piping and pump exposure

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The cooling water passage is merged with the crank case structure, forming an integrated component. The passage is formed by providing a recessed portion in the crank case and covering it with a passage cover, eliminating the need for separate external piping and pump components while maintaining the cooling function.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The water pump is nested inside the crank case, specifically positioned within the recessed portion of the crank case. This nesting arrangement hides the pump within the engine structure, improving external appearance while maintaining accessibility for maintenance through the passage cover.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Temperature

If water pump and water piping are provided outside the engine, then cooling function is achieved, but manufacturing cost increases

Engineering Contradiction:

Improvecooling functionVSAvoidmanufacturing cost

Core Design Contradiction:

TemperatureVSEase of manufacture

Solution Approach 1:

Inventive Principle:

Principle #5Merging (Combining)

3Device complexity

If cooling water passage is formed integrally with crank case, then manufacturing cost is reduced and appearance is improved, but passage formation complexity increases

Engineering Contradiction:

Improveintegration of cooling passageVSAvoidpassage formation process

Core Design Contradiction:

Device complexityVSEase of manufacture

Solution Approach 1:

The integrated cooling water passage is segmented into the recessed portion formed in the crank case and the separate passage cover. This segmentation allows the passage to be formed as part of the crank case casting process while enabling easy assembly and disassembly for maintenance, reducing the complexity of forming the complete passage integrally.

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 design improves the engine's external appearance and reduces manufacturing costs by integrating the cooling water passage with the crank case, while maintaining effective cooling of the engine components.

Implementation Method 1

a water pump; and a cooling water passage that connects the water pump and the water jacket

Methodology Applied

Scientific EffectPump: Pump

Implementation Method 2

cooling water is passed from the cooling water passage through the water jacket formed in the cylinder, thereby effectively cooling the cylinder

Methodology Applied

Scientific EffectHeat conduction: Conduction (thermal)

Data Source

PatentUS7481186B2Engine with cooling water passage formed inside crank case

Publication Date: 2009.01.27 YAMAHA MOTOR CO LTD

AI summary

A cooling water structure for an engine with improved external appearance and reduced cost. A first passage section of a cooling water passage discharges cooling water from a water pump to water jackets of front and rear cylinders. The first passage section is formed in a surface of a partition wall of a right case that is an inside wall surface of a crank case. The water pump is accommodated with the first passage section in a crank chamber of the crank case.