Self-Regulating Heat Exchanger Using Phase Change Medium
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Solution Overview
Problem
Existing heat exchanger systems face challenges in efficiently transmitting exhaust gas heat to working media of internal combustion engines, particularly after a cold start, due to high temperature fluctuations, which require costly and space-intensive solutions to prevent overheating.
Innovation Solution
A self-regulating heat exchanger system with a hermetically sealed volume containing a heat transmission medium that transitions from liquid to gas state at a predetermined threshold temperature, minimizing heat transfer when exhaust gas temperatures exceed this threshold, using a ratio of medium to volume that ensures negligible heat conduction in the gaseous state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a heat exchanger is designed to efficiently transfer heat at low exhaust temperatures, then heat transfer efficiency is improved, but the system cannot handle high exhaust temperatures without causing overheating
Solution Approach 1:
The patent utilizes phase change of the heat transmission medium as a parameter change mechanism. The medium transitions from liquid to gaseous state at a predetermined threshold temperature, fundamentally changing its heat conduction properties and automatically regulating heat transfer based on temperature conditions
Solution Approach 2:
The core invention employs phase transition of the heat transmission medium between liquid and gaseous states. At temperatures below the threshold, the medium remains liquid and efficiently transfers heat. When the threshold is exceeded, the medium vaporizes, and since the gaseous state has negligible heat conduction, heat transfer is automatically interrupted, preventing overheating
2Object-affected harmful factors
If switchable heat exchangers with porous substances or bypass systems are used to control heat transfer at high temperatures, then overheating is prevented, but device complexity and installation space increase
Solution Approach 1:
The heat exchanger system is designed to automatically regulate its own heat transfer function through the inherent phase change properties of the heat transmission medium. No external control components, sensors, or actuation systems are required - the system self-adjusts based on temperature conditions, eliminating the need for complex control mechanisms
Solution Approach 2:
The invention extracts the control function from separate mechanical components and embeds it directly into the thermal properties of the heat transmission medium itself. The medium's phase change behavior inherently provides the temperature-dependent heat transfer control, removing the need for additional control devices
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 efficient heat transfer to working media shortly after a cold start without additional control components, reducing costs and installation space, while automatically interrupting heat transfer at high exhaust gas temperatures to prevent overheating.
Implementation Method 1
the heat transmission medium (38) is configured to transmit the heat from the exhaust gas of the internal combustion engine (10) to the working medium of the internal combustion engine (10), wherein the ratio between the predetermined volume of heat transmission medium and the predetermined heat exchanger volume is set such that the heat transmission medium (38) is substantially completely in the gaseous state when the temperature of the exhaust gas exceeds a predetermined threshold value
Implementation Method 2
the heat transmission medium (38) which is arranged in the predetermined heat exchanger volume and is substantially completely in the liquid state at room temperature and normal pressure
Data Source
AI summary
Various embodiments include a system for transmitting heat from an exhaust gas of an internal combustion engine to a working medium comprising: a first heat exchanger connected to the exhaust gas; a second heat exchanger connected to the working medium and the first heat exchanger; and a heat transmission medium arranged in a predetermined heat exchanger volume and substantially completely in a liquid state with a predetermined volume of heat transmission medium at room temperature and normal pressure. The heat exchangers define the hermetically sealed heat exchanger volume. The heat transmission medium transmits heat from the exhaust gas to the working medium. A ratio between the predetermined volume of the heat transmission medium and the predetermined heat exchanger volume is set such that the heat transmission medium is substantially completely in a gaseous state when a temperature of the exhaust gas exceeds a threshold value.