Water Jacket Spacer Structure for Bore Cooling and Vibration Stability

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Solution Overview

Problem

Conventional water jacket spacers in water-cooled engines suffer from undesired deformation and vibration due to coolant flow, leading to inadequate cooling of the bore upper part and potential engine performance degradation or damage.

Innovation Solution

A water jacket spacer structure with a contact member that changes posture between a separated and contacting position relative to the cylinder bore wall, using materials with higher thermal conductivity than the spacer body, to ensure effective cooling and prevent deformation during engine operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the water jacket spacer is inserted into the water jacket during engine assembly without coolant, then high workability is ensured, but the spacer cannot prevent deformation and vibration during engine operation

Engineering Contradiction:

Improveworkability during assemblyVSAvoidstability during operation

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The contact member is pre-configured in a contracted state during assembly, allowing easy insertion into the water jacket. After coolant injection and engine operation begin, the contact member automatically expands to its functional state, providing the necessary support and stability. This preliminary configuration resolves the contradiction by preparing the system in an easily installable state that transforms into a stable operational state.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The contact member transitions from a static contracted state during assembly to a dynamic expanded state during operation. This dynamic behavior allows the spacer to adapt to different operational conditions - remaining compact for easy installation while expanding to prevent deformation and vibration when coolant flows and the engine operates, thus resolving the stability issue.

Inventive Principle:

Principle #15Dynamics

2Temperature

If the channel width of the water jacket is made wider in the bore upper part section, then cooling effectiveness is improved, but the spacer becomes more susceptible to deformation and vibration

Engineering Contradiction:

Improvecooling effectivenessVSAvoidspacer stability

Core Design Contradiction:

TemperatureVSStability of the object's composition

Solution Approach 1:

The contact member is strategically positioned to provide localized support specifically in the bore upper part section where the channel width is increased for cooling. This local reinforcement allows the water jacket to maintain its optimized wide channel geometry for thermal management while the contact member locally prevents deformation and vibration, resolving the contradiction between cooling effectiveness and structural stability.

Inventive Principle:

Principle #3Local quality

3Temperature

If the elastic body is used to expand the spacer after insertion, then the lagging material contacts the cylinder bore wall for thermal management, but the spacer may deform under coolant flow pressure

Engineering Contradiction:

Improvethermal managementVSAvoidresistance to deformation

Core Design Contradiction:

TemperatureVSStrength

Solution Approach 1:

The water jacket spacer employs a composite structure combining the elastic body for thermal management function with the contact member for structural reinforcement. The elastic body enables the lagging material to contact the cylinder bore wall for effective thermal management, while the contact member provides additional structural support to resist deformation from coolant flow pressure, thus resolving the contradiction between thermal management and structural strength.

Inventive Principle:

Principle #40Composite materials

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

The structure ensures high workability during assembly, prevents spacer deformation, and enhances thermal efficiency by efficiently transferring heat from the bore upper part to the coolant, thereby improving engine performance and preventing knocking.

Implementation Method 1

the contact member... having a higher heat conductivity than the spacer body member and the wall of the cylinder bore

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

an expandable member... changeable between a state where the expandable member is contracted to bring the contact member into the first posture, and a state where the expandable member is extended to bring the contact member into the second posture

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS12577901B2Water jacket spacer structure

Publication Date: 2026.03.17 MAZDA MOTOR CORP

AI summary

A structure of a water jacket spacer inserted into a water jacket between an outer wall surface of a cylinder bore wall of an engine and an inner wall surface of a cylinder block includes a spacer body member including upper and lower wall parts which are closer to the inner and outer wall surfaces in upper and lower parts of the water jacket, respectively, and an elongated contact member fixed at one end to the upper wall part, changeable between first and second postures where it is separated from and contacts with the outer wall surface, respectively. The contact member is in the first posture when coolant is not filled in the water jacket and the engine is not operated, and is in the second posture when the coolant is filled in the water jacket and the engine is operated.