Inclined Ring Member Combustion Chamber Heat Loss

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Solution Overview

Problem

Internal combustion engines face challenges in maintaining high combustion chamber temperatures due to heat loss caused by ring members positioned at the upper portion of the cylinder, which affects combustion efficiency and fuel efficiency.

Innovation Solution

A cylindrical ring member with an inclined outer peripheral surface and decreasing thickness towards the bottom dead center is provided at the stepped portion of the cylinder, reducing heat loss and enhancing heat shielding while preventing gas leakage and soot adhesion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a ring member is provided at the upper portion of the cylinder to prevent gas leakage and soot adhesion, then reliability is improved, but heat loss increases and combustion chamber temperature decreases

Engineering Contradiction:

Improvegas leakage preventionVSAvoidheat loss

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The ring member is designed with non-uniform thickness, being thicker at the upper portion and thinner at the lower portion. This local quality variation allows the upper thick portion to effectively prevent gas leakage and soot adhesion, while the lower thin portion reduces heat loss and improves heat shielding performance.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The ring member employs an asymmetric thickness distribution rather than uniform thickness. The outer peripheral surface is formed as an inclined surface, creating asymmetry that optimizes both sealing function at the top and thermal insulation function at the bottom, resolving the contradiction between reliability and heat loss.

Inventive Principle:

Principle #4Asymmetry

2Object-affected harmful factors

If a ring member is provided at the upper portion of the cylinder to prevent soot adhesion, then cleanliness is improved, but heat loss increases

Engineering Contradiction:

Improvesoot adhesionVSAvoidheat loss

Core Design Contradiction:

Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The ring member features localized quality variation with greater thickness at the upper portion where soot adhesion occurs, providing effective soot prevention. The lower portion has reduced thickness to minimize heat loss, achieving both cleanliness and energy efficiency.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The asymmetric thickness profile of the ring member, with the outer peripheral surface forming an inclined surface, enables differential functionality: the upper thick section addresses soot adhesion while the lower thin section reduces heat loss.

Inventive Principle:

Principle #4Asymmetry

3Ease of manufacture

If the ring member has uniform thickness to simplify manufacturing, then ease of manufacture is improved, but heat shielding performance deteriorates

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidheat shielding performance

Core Design Contradiction:

Ease of manufactureVSTemperature

Solution Approach 1:

The ring member implements local quality differentiation with varying thickness across its height. The upper portion is thicker for structural integrity and sealing, while the lower portion is thinner to enhance heat shielding, optimizing both manufacturing feasibility and thermal performance.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The asymmetric thickness distribution with an inclined outer peripheral surface creates optimal heat shielding performance by positioning less material away from the combustion chamber center, reducing thermal mass in the heat loss path while maintaining manufacturing practicality.

Inventive Principle:

Principle #4Asymmetry

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 configuration reduces heat loss, enhances heat shielding, and improves fuel efficiency by maintaining higher combustion chamber temperatures and preventing gas leakage and soot adhesion, thus optimizing combustion performance.

Implementation Method 1

an outer peripheral surface of the ring member is an inclined surface, where a lower end of the outer peripheral surface is positioned closer to the center in a radial direction of the ring member than an upper end of the outer peripheral surface

Methodology Applied

Scientific EffectHeat loss reduction through geometric configuration: Thermal Insulation

Implementation Method 2

a thickness of the ring member decreases toward a bottom dead center of the piston

Methodology Applied

Scientific EffectHeat shielding through reduced thermal mass: Thermal Insulation

Data Source

PatentUS12025073B2Internal combustion engine

Publication Date: 2024.07.02 ISUZU MOTORS LTD

AI summary

An internal combustion engine includes: a cylinder in which a piston reciprocates; a stepped portion that is formed on an upper end portion of an inner peripheral surface of the cylinder; and a ring member having a cylindrical shape provided to the stepped portion. The thickness of the ring member decreases toward the bottom dear center of the piston, and an outer peripheral surface of the ring member is an inclined surface, where a lower end of the outer peripheral surface is positioned closer to the center in the radial direction of the ring member than an upper end of the outer peripheral surface.