Water Jacket Thermal Barrier for Internal Combustion Engine
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Solution Overview
Problem
Internal combustion engines with secondary air passages located above the combustion chamber face issues such as increased intake air temperature, reduced volumetric efficiency, and decreased reliability due to heat radiation, which can lead to knocking and engine oil deterioration.
Innovation Solution
A water jacket is strategically placed between the secondary air passage and either the exhaust or intake passage to cool down high-temperature exhaust gas and prevent heat radiation from affecting engine components, thereby reducing adverse effects on the engine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a secondary air passage is located above the combustion chamber to reduce component count and processing sites, then manufacturing cost is reduced, but heat radiation from the secondary air passage causes adverse effects on engine components
Solution Approach 1:
A water jacket is introduced as an intermediary component between the secondary air passage and the exhaust passage. This water jacket contains coolant that absorbs heat from the exhaust gas, thereby preventing direct heat transfer to the secondary air passage and reducing heat radiation effects on engine components while maintaining the cost-effective configuration
2Device complexity
If the secondary air passage is positioned to extend along the exhaust passage for compact design, then device complexity is reduced, but intake air temperature increases due to heat radiation
Solution Approach 1:
The water jacket serves as a thermal barrier positioned between the hot exhaust passage and the secondary air passage that carries intake air. By circulating coolant through the water jacket, heat from the exhaust gas is absorbed before it can radiate to the intake air, thus maintaining lower intake air temperature while preserving the compact structural design
3Device complexity
If the secondary air passage is located above the combustion chamber for simplified structure, then component count is reduced, but volumetric efficiency decreases due to increased intake air temperature
Solution Approach 1:
The water jacket acts as a thermal isolation layer between the hot exhaust system and the cooler secondary air passage. This allows the simplified structural arrangement to be maintained while the coolant circulation prevents excessive heating of the intake air, thereby preserving volumetric efficiency despite the reduced component count
4Ease of manufacture
If the secondary air passage extends along the exhaust passage for cost reduction, then manufacturing cost is reduced, but reliability decreases due to increased valve operating mechanism temperature
Solution Approach 1:
The water jacket is positioned to provide thermal protection to the valve operating mechanism area. By absorbing heat from the exhaust gas through coolant circulation, it creates a thermal buffer that prevents excessive temperature rise in the valve operating mechanism, thereby maintaining reliability while keeping the cost-effective structural configuration
5Device complexity
If the secondary air passage is located above the combustion chamber for compact design, then device complexity is reduced, but engine oil deterioration accelerates due to heat exposure
Solution Approach 1:
The water jacket serves as a thermal barrier between the hot exhaust passage and the engine oil. By circulating coolant through the water jacket, it absorbs radiant heat from the exhaust gas, thereby reducing the thermal exposure of the engine oil and slowing down its deterioration process while maintaining the compact structural design
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 implementation of a water jacket effectively cools high-temperature exhaust gas and minimizes heat radiation, enhancing engine performance by reducing intake air temperature and maintaining component reliability.
Implementation Method 1
the high-temperature exhaust gas that flows in and stays in the secondary air passage is cooled down by the coolant flowing through the water jacket
Data Source
AI summary
An internal combustion engine is provided that includes a combustion chamber; a secondary air passage located above the combustion chamber; an exhaust passage that communicates with the combustion chamber; and a water jacket that is located between the exhaust passage and the secondary air passage.