Piston Heat Insulation Gap and Protective Hood

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Solution Overview

Problem

Combustion engine pistons face issues with high temperature-induced heat expansion, leading to damage and coking of piston surfaces and oil channels, which can result in engine seizure and reduced efficiency.

Innovation Solution

A piston design featuring a separate piston crown and skirt with a heat insulation gap sealed by appropriate seals, and a protective hood on the piston pin that covers the bottom side of the piston crown, preventing oil from burning and clogging oil channels, while allowing for different materials to be used for the crown and skirt to manage heat expansion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cooling arrangements are used to reduce heat from piston parts, then temperature load on parts is reduced, but heat transfer between piston crown and skirt is minimized, preventing coking and clogging

Engineering Contradiction:

Improvepiston durabilityVSAvoidheat transfer efficiency

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The piston is divided into separate crown and skirt portions with a heat insulation gap between them, allowing different materials to be used for each part. The crown can be made of heat-resistant material while the skirt uses standard material, optimizing both thermal management and mechanical properties.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A heat insulation gap acts as an intermediary barrier between the hot piston crown and the cooler skirt, reducing unwanted heat transfer to the skirt and preventing coking of the piston surfaces.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If high temperatures are used to increase engine efficiency, then combustion work is improved, but heat expansion causes damage to pistons and piston rings

Engineering Contradiction:

Improveengine efficiencyVSAvoidheat expansion damage

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

Different materials are used for different parts of the piston based on their specific functional requirements. The crown uses high-temperature resistant material for combustion exposure, while the skirt uses material optimized for mechanical support and ring engagement, allowing each part to handle its specific thermal and mechanical loads.

Inventive Principle:

Principle #3Local quality

3Reliability

If a divided piston configuration with heat insulation gap is used, then heat expansion effects are reduced, but device complexity increases

Engineering Contradiction:

Improvepiston performanceVSAvoidpiston structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

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 effectively reduces heat transfer between the piston crown and skirt, preventing coking and clogging, enhancing engine efficiency and fuel consumption while maintaining engine oil quality.

Implementation Method 1

a heat insulation gap between a piston crown portion being exposed to the highest temperatures and a piston skirt supporting the piston rings

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 2

The protection sealingly engages an inner piston skirt portion. In assembled condition it forms a gap towards the piston crown and it is at least partly arranged inside an outer piston skirt portion. That makes it possible to avoid problems of oil burning onto the piston and thus of coking and clogging of oil channels.

Methodology Applied

Scientific EffectCoking prevention:

Data Source

PatentUS8978612B2High temperature piston

Publication Date: 2015.03.17 NYBERG PETER

AI summary

In a piston (1) for combustion engines are included a piston crown (2), a piston skirt (3) and portions (4A, 4B; 13) for receiving a piston pin (5) by means of which the piston is pivotally supported on a connection rod, whereby a protection (7) covering a major portion of a bottom side of the piston crown is supported on the piston pin. The protection is fitted in sealing engagement with a first inner portion of the piston skirt, forming an uninterrupted gap in relation to a main portion of the piston crown and with at least a portion of the protection being provided at a distance inside a second outer portion of the piston skirt.