Cylinder Block Density Gradient for Heat Conduction Control

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Solution Overview

Problem

The existing heat shield structures in internal combustion engines, such as those described in Japanese Utility Model Application Publication No. 6-22547 U, fail to effectively suppress heat conduction from the cylinder head side to the side farther from the cylinder head in the cylinder axial direction within the cylinder bore wall.

Innovation Solution

A cylinder block with a cylinder bore wall featuring multiple layers of varying densities, where the layer closer to the cylinder head has a higher density and the layer farther from the cylinder head has a lower density, made of the same material but with different porosity, is designed to suppress heat conduction. This is achieved through a three-dimensional molding process that laminates layers with varying densities, with the high-density layer closest to the cylinder head and a low-density layer farther away, integrated into the cylinder liner and main wall structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a uniform density structure is used in the cylinder bore wall, then manufacturing is simpler, but heat conduction from the cylinder head side cannot be effectively suppressed

Engineering Contradiction:

Improveheat conduction lossVSAvoidcylinder bore wall structure

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The cylinder bore wall is divided into multiple layers with different densities along the cylinder axial direction. The high-density layer is positioned closer to the cylinder head while the low-density layer is positioned farther away, creating a segmented structure that optimizes heat conduction control at different positions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the cylinder bore wall are assigned different density characteristics. The high-density region near the cylinder head provides better heat shielding, while the low-density region farther away reduces overall heat conduction, creating local quality variations to optimize thermal management.

Inventive Principle:

Principle #3Local quality

2Loss of energy

If a high-density material is used throughout the cylinder bore wall, then structural strength is improved, but heat conduction from the cylinder head side increases

Engineering Contradiction:

Improveheat conduction lossVSAvoidcylinder bore wall strength

Core Design Contradiction:

Loss of energyVSStrength

Solution Approach 1:

The cylinder bore wall is segmented into high-density and low-density layers along the axial direction. The high-density layer near the cylinder head provides heat shielding while the low-density layer reduces overall heat conduction, balancing thermal management requirements with structural considerations.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The cylinder bore wall exhibits local quality variations in density. The high-density region near the cylinder head addresses heat conduction suppression, while the low-density region farther away minimizes thermal transfer, creating localized properties optimized for different functional requirements.

Inventive Principle:

Principle #3Local quality

3Loss of energy

If a low-density structure is used in the cylinder bore wall, then heat conduction is reduced, but manufacturing precision and structural integrity deteriorate

Engineering Contradiction:

Improveheat conduction lossVSAvoidcylinder bore wall formation precision

Core Design Contradiction:

Loss of energyVSManufacturing precision

Solution Approach 1:

The cylinder bore wall is constructed with segmented layers of different densities. The high-density layer near the cylinder head provides thermal management benefits while the low-density layer farther away reduces heat conduction, with each layer manufactured to precise specifications.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different sections of the cylinder bore wall have different density qualities optimized for their specific functions. The high-density section near the cylinder head provides structural support and heat shielding, while the low-density section farther away minimizes thermal transfer.

Inventive Principle:

Principle #3Local quality

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 effectively reduces heat conduction along the cylinder axial direction, allowing for quicker engine warming and improved cooling performance, reducing friction and enhancing the engine's ability to manage heat efficiently during both warming up and high-load operations.

Implementation Method 1

heat conduction from a side closer to the cylinder head toward a side farther from the cylinder head in a cylinder axial direction

Methodology Applied

Scientific EffectHeat conduction: Conduction (thermal)

Data Source

PatentUS10408159B2Cylinder block of internal combustion engine and cylinder block manufacturing method

Publication Date: 2019.09.10 TOYOTA JIDOSHA KK

AI summary

A cylinder block of an internal combustion engine includes a cylinder bore wall that holds a piston so as to allow the piston to reciprocate. In at least one part of the cylinder bore wall in a cylinder axial direction, the density of a layer located farther from a cylinder head is lower than the density of a layer located closer to the cylinder head in the cylinder axial direction.