Insulated Exhaust Heater with Tortuous Support for High Power Density
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing exhaust systems for internal combustion engines face challenges in achieving high power density heating for exhaust gases, especially under varying engine conditions such as low idle speeds, where heat transfer efficiency is compromised due to lower exhaust gas velocities.
Innovation Solution
The proposed heating apparatus incorporates a support member with a tortuous geometry that restricts movement of the heater elements and enhances heat transfer by flanking opposed sides of the heater elements, thereby increasing power density without increasing the heater temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If heater elements are installed in exhaust pipes to heat exhaust gases, then heat transfer to exhaust gas is improved, but the heater elements are subjected to harsh environmental conditions including vibration, mechanical shock, and temperature cycling
Solution Approach 1:
The heater element is divided into multiple sections (first section, second section, third section) with different material compositions. Each section is optimized for specific operating conditions - the first section handles high temperature zones while the third section handles lower temperature zones with different thermal expansion characteristics, thereby improving overall reliability under temperature cycling
Solution Approach 2:
Different portions of the heater element are made from materials with different properties. The first section uses a material with higher melting point for high temperature exposure, while the third section uses a material with lower melting point but better vibration resistance. This local differentiation allows each region to perform optimally under its specific thermal and mechanical conditions
2Power
If heater temperature is increased to improve heat transfer efficiency, then power density is improved, but the durability of the heater elements is compromised
Solution Approach 1:
The patent changes the material parameters (melting point, thermal conductivity, vibration resistance) of different heater sections to enable operation at higher power densities without compromising durability. By selecting materials with optimized properties for each section, the system can operate at higher temperatures and power densities while maintaining element integrity
Solution Approach 2:
The heater element uses composite construction with different materials in different sections. The first section uses a material with high melting point for high temperature operation, while the third section uses a material with lower melting point but enhanced vibration resistance. This composite approach allows the heater to achieve high power density while maintaining durability through material optimization
3Productivity
If heater elements are exposed to higher temperatures to increase heating efficiency, then heat transfer rate is improved, but the risk of material failure increases
Solution Approach 1:
The heater element is segmented into multiple sections, each optimized for its specific thermal environment. The first section is designed for high temperature operation with materials having high melting points, while the third section is designed for lower temperature operation with materials having better thermal shock resistance, thereby reducing overall material failure risk
Solution Approach 2:
Different sections of the heater element have different material compositions tailored to their local thermal and mechanical conditions. This local optimization ensures that each section operates within its safe operating limits, reducing the risk of material failure while maintaining high heating efficiency
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 allows for a significant increase in power density, achieving up to 84 watts/in2 for the sheath and 230 watts/in2 for the resistive heating wire, while maintaining the durability and temperature of the heater elements, even under low engine speed conditions.
Implementation Method 1
at least one heater element
Implementation Method 2
arranged to increase heat transfer from the at least one heater element to an exhaust gas flowing through the container body
Data Source
AI summary
An exhaust gas heater system for an exhaust system of an internal combustion engine includes a housing and a heating element. The housing includes an outer peripheral wall disposed about a central axis and defining an interior hollow space configured to receive exhaust gas from an exhaust pipe of the exhaust system such that the exhaust gas flows through the interior hollow space. The heating element is positioned within the hollow space and including a first end and a second end. The heating element includes a first section proceeding in a first direction and a second section proceeding in a second direction. The support structure is configured to extend along a path conforming to a path of the first and second sections.