Multilayer Heat Shield Film for Engine Emission Control
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Solution Overview
Problem
Conventional internal combustion engines with heat shield films fail to adequately reduce hydrocarbon emissions and achieve high heat-insulating properties, leading to inefficient thermal management and increased photochemical smog formation.
Innovation Solution
A heat shield component comprising a substrate with a first layer of polyimide or polyamide-imide material having low thermal conductivity and volumetric specific heat, and a second layer providing closed pores to enhance heat insulation, along with a third layer of silica or amorphous carbon for improved thermal resistance, while maintaining a smooth surface roughness to minimize heat exchange and hydrocarbon adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heat shield film is applied to the combustion chamber wall surface, then heat-insulating properties are improved, but hydrocarbon emissions are not sufficiently reduced
Solution Approach 1:
The heat shield film is divided into multiple layers with different functions: a first layer (metal or metal oxide) for heat insulation and a second layer (resin) for reducing hydrocarbon emissions. This segmentation allows each layer to optimize its specific function, resolving the contradiction between heat insulation and emission reduction.
Solution Approach 2:
The invention uses a composite structure combining inorganic materials (metal or metal oxide) with organic resin materials. The metal/metal oxide layer provides thermal insulation while the resin layer reduces hydrocarbon emissions through its combustion characteristics, achieving both objectives simultaneously.
2Use of energy by moving object
If the inner wall surface is provided with a thin film for heat insulation, then thermal efficiency is improved, but the emission amount of hydrocarbon is not sufficiently reduced
Solution Approach 1:
The single thin film is segmented into two functional layers: the first layer maintains thermal efficiency through heat insulation, while the second layer specifically addresses hydrocarbon emissions. This resolves the contradiction between improving thermal efficiency and reducing emissions.
Solution Approach 2:
Different regions of the heat shield film have different material properties optimized for specific functions. The first layer has properties optimized for heat insulation to improve thermal efficiency, while the second layer has properties optimized for reducing hydrocarbon emissions, allowing local optimization of each function.
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 heat shield component significantly reduces hydrocarbon emissions and improves thermal insulation, enhancing fuel efficiency and reducing photochemical smog formation by effectively blocking heat and minimizing surface area for fuel gas adhesion.
Implementation Method 1
a first layer (10) arranged on the substrate (5), including the pores (15), and having a thermal conductivity of 0.3 W/(m·K) or less and a volumetric specific heat of 1200 kJ/(m3·K) or less
Implementation Method 2
a second layer (20) arranged on the first layer (10) to provide the closed pores (25) between the first layer (10) and the second layer (20)
Implementation Method 3
The surface roughness on a top surface of the heat shield film is set to a predetermined value or lower
Data Source
AI summary
A heat shield component includes a substrate, and a heat shield film arranged on the substrate. The heat shield film includes a first layer arranged on the substrate, including pores, and having a thermal conductivity of 0.3 W/(m·K) or less and a volumetric specific heat of 1200 kJ/(m3·K) or less, and a second layer arranged on the first layer to provide closed pores between the first layer and the second layer. The heat shield film has a surface roughness on a top surface which is 1.5 μm Ra or less. The heat shield component can achieve high heat-insulating properties and an improved effect of reducing the emission amount of hydrocarbon in an internal combustion engine, for example.