Nucleate Boiling Cooling System for Internal Combustion Engines
Solution Overview
Problem
Internal combustion engines face parasitic losses and heat management issues due to uncontrolled boiling in coolant systems, which can lead to reduced heat flux and potentially catastrophic temperature increases in metal parts, and existing active control systems are costly and complex.
Innovation Solution
A cost-effective cooling system for internal combustion engines that uses a pump to induce nucleate boiling, a sensor to detect boiling conditions, and a movable dividing wall to control pressure, maintaining optimal heat flux through a variable volume chamber and pressure adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If active control systems with sensors and additional pumps are used to maintain nucleate boiling, then heat flux control is improved, but device complexity and cost increase
Solution Approach 1:
The cooling system uses the engine's existing water pump to provide the necessary pressure fluctuations for nucleate boiling, rather than requiring a separate active control pump. The system self-regulates by utilizing the natural pressure variations already present in the engine cooling circuit, eliminating the need for additional active control components while maintaining effective heat flux control
Solution Approach 2:
The existing water pump in the engine cooling system is made to serve a dual function: its primary role of circulating coolant is enhanced to also provide the pressure fluctuations necessary for inducing and maintaining nucleate boiling. This multi-functionality eliminates the need for separate active control devices, reducing system complexity while achieving reliable heat flux control
2Stress or pressure
If uncontrolled boiling occurs in the coolant passages, then pressure relief is triggered, but heat flux is drastically reduced and metal temperatures increase
Solution Approach 1:
The system utilizes periodic pressure fluctuations generated by the engine's water pump operation to repeatedly induce and collapse vapor bubbles in the coolant passages. This periodic action maintains the cooling system in a controlled nucleate boiling state, preventing both uncontrolled macro-boiling and complete liquid-to-metal contact, thereby stabilizing heat flux and preventing excessive metal temperatures
Solution Approach 2:
The invention deliberately induces controlled phase transitions between liquid and vapor phases in the coolant by maintaining pressure fluctuations that promote nucleate boiling. These controlled phase transitions create vapor bubbles that enhance heat transfer from metal surfaces to the coolant, preventing direct liquid-to-metal contact and reducing metal temperatures while maintaining effective heat flux
3Productivity
If nucleate boiling is maintained through conventional means, then heat flux increases, but additional complications and cost are introduced
Solution Approach 1:
The system leverages the engine's existing water pump and cooling circuit pressure variations to automatically induce and maintain nucleate boiling, without requiring additional active control devices, sensors, or complex control systems. This self-service approach achieves enhanced heat flux through nucleate boiling while avoiding the additional manufacturing costs and complications associated with active control systems
Solution Approach 2:
The invention achieves controlled nucleate boiling by utilizing and optimizing the natural pressure parameters already present in the engine cooling system. By adjusting and leveraging the pressure fluctuations generated during normal engine operation, the system maintains optimal conditions for nucleate boiling without requiring additional components or increasing manufacturing complexity, thereby improving heat flux cost-effectively
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 solution allows for higher operating temperatures and a more compact engine design by maintaining nucleate boiling conditions, preventing uncontrolled boiling and reducing metal temperatures across various operational conditions while being more economical and simpler in design.
Implementation Method 1
the pump being selected to cause nucleate boiling at least around the combustion chamber
Implementation Method 2
This is known as nucleate boiling in which bubbles are generated on a microscopic scale. This allows significant increases in heat flux
Implementation Method 3
At least one chamber is connected to the cooling system with the chamber having a dividing wall movable within the chamber to vary the volume of the chamber connected to the cooling system
Data Source
AI summary
A cooling system for a liquid cooled internal combustion engine having coolant passages and a heat exchanger selected to operate the engine cooling system in the region of nucleate boiling. A sensor detects the presence of nucleate boiling and a variable volume chamber has a flexible diaphragm urged on one side by controlled air pressure and responsive to the sensor maintain the coolant system pressure at a level maintaining optimum nucleate boiling to increase heat flux from the engine and reduce overall size of the system.