Engine Water Jacket Inter-Port Passage Cooling

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Solution Overview

Problem

Existing engine designs, such as those described in JP 2004-270457 A and US2003/0213453A, face challenges in improving cooling efficiency due to the absence of a water jacket between exhaust ports, leading to inefficient heat dissipation.

Innovation Solution

The engine incorporates a water jacket with a central passage near the spark plug hole and an inter-port passage located between the exhaust ports, which connects to the central passage, preventing air collection and enhancing cooling efficiency by allowing coolant to circulate effectively between the exhaust ports.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the water jacket is not formed between the exhaust ports where the drainage hole passes through, then the structure is simpler, but the cooling efficiency deteriorates

Engineering Contradiction:
Improvewater jacket structureVSAvoidcooling efficiency
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

The water jacket is segmented into two distinct passages: a central passage extending along the spark plug hole, and an inter-port passage formed between the exhaust ports. This segmentation allows the cooling system to navigate around the drainage hole obstruction while maintaining effective cooling coverage in critical areas.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cooling system provides localized cooling by positioning the central passage near the spark plug hole where heat generation is intense, and the inter-port passage between exhaust ports where another heat concentration zone exists. Each passage is strategically located to address specific thermal challenges in different regions of the engine head.

Inventive Principle:
Principle #3Local quality

2Temperature

If the inter-port passage is formed between the exhaust ports, then the cooling efficiency is improved, but the device complexity increases

Engineering Contradiction:
Improvecooling efficiencyVSAvoidwater jacket structure
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The central passage and inter-port passage are merged into a unified water jacket system that shares common coolant flow and structural integration. This merging allows the complex cooling configuration to function as a cohesive unit, where the passages work together to maximize cooling efficiency without requiring separate independent systems.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The water jacket structure serves multiple functions simultaneously: the central passage cools the spark plug hole region, the inter-port passage cools the exhaust port region, and both passages work together to prevent air collection. This multi-functionality justifies the increased structural complexity by delivering comprehensive cooling coverage.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Temperature

If the central passage is positioned near the spark plug hole, then the cooling efficiency is improved, but the space for other components is reduced

Engineering Contradiction:
Improvecooling efficiencyVSAvoidavailable space
Core Design Contradiction:
TemperatureVSVolume of moving object

Solution Approach 1:

The central passage is positioned in the axial dimension near the spark plug hole rather than occupying radial space that would interfere with other components. By utilizing the depth dimension of the engine head, the cooling passage achieves proximity to the heat source without compromising the lateral space available for other engine components.

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 improves the cooling efficiency of the engine by ensuring efficient coolant circulation and preventing air accumulation, thereby maintaining optimal operating temperatures.

Implementation Method 1

Coolant circulates in the water jacket. The water jacket includes a central passage and an inter-port passage.

Methodology Applied
Scientific EffectCooling: Cooling

Implementation Method 2

Coolant circulates in the water jacket... improving cooling efficiency by allowing coolant to circulate effectively between the exhaust ports

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Data Source

PatentEP2826975B1Engine and saddle type vehicle
Publication Date: 2015.12.02 YAMAHA MOTOR CO LTD
  • EP2826975B1 patent drawingFigure 1
  • EP2826975B1 patent drawingFigure 2
  • EP2826975B1 patent drawingFigure 3

AI summary

An engine includes a piston and a casing including a cylinder. The cylinder houses the piston. The cylinder and the piston forms a combustion chamber. The casing has as intake port, a plurality of exhaust ports, a spark plug hole, a drainage hole, and a water jacket. The spark plug hole extends to the combustion chamber. A spark plug is housed in the spark plug hole. The drainage hole extends from the spark plug hole. The water jacket includes a central passage and an inter-port passage. The central passage is near the spark plug hole. The inter-port passage extends to the central passage. The inter-port passage is formed between the plurality of exhaust ports. The inter-port passage is located between the drainage hole and the cylinder in a central axis direction of the spark plug hole.