Vehicle Coolant Flow Valve Control to Prevent Exhaust Heat Boiling
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Solution Overview
Problem
The existing exhaust heat recovery systems in hybrid vehicles face issues with coolant flow stop functions leading to boiling phenomena and damage due to continuous heat transfer, as the bypass valve fails to operate at desired times, especially when coolant flow is stopped or temperature is low.
Innovation Solution
A system and method for controlling coolant flow using an integrated flow control valve and a drive motor actuator, which regulates coolant distribution based on outside air and coolant temperature, allowing selective passage through an ATF warmer, heater, and exhaust heat recovery system to prevent boiling and enhance engine warm-up.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the integrated flow control valve stops coolant flow to quickly warm up the engine, then the engine warm-up speed is improved, but the exhaust heat recovery system overheats and causes boiling damage
Solution Approach 1:
The controller continuously monitors coolant temperature and flow conditions, and adjusts the bypass valve operation accordingly. When coolant flow is stopped for engine warm-up, the controller detects the temperature rise in the exhaust heat recovery system and activates the bypass valve to prevent overheating, creating a closed-loop control system that resolves the contradiction between warm-up speed and system reliability
Solution Approach 2:
The system dynamically adjusts the bypass valve opening degree based on real-time operating conditions. The valve can transition from fully closed (to maximize heat recovery during normal operation) to partially or fully open (to prevent boiling during flow stop conditions), allowing the system to adapt its behavior to different operational states and resolve the contradiction between different operational requirements
2Reliability
If the bypass valve is opened to prevent boiling in the exhaust heat recovery system, then the system reliability is improved, but the engine warm-up efficiency deteriorates
Solution Approach 1:
The controller precisely controls the bypass valve opening degree as a variable parameter, allowing partial bypass operation. This enables the system to maintain reliability by preventing boiling while minimizing the impact on warm-up efficiency, as the bypass can be adjusted to the minimum necessary degree rather than being fully open, thus optimizing the trade-off between reliability and productivity
3Device complexity
If the wax-based bypass valve is used to automatically open based on coolant temperature, then the device complexity is reduced, but the control precision and timing are insufficient
Solution Approach 1:
The patent replaces the purely mechanical wax-based actuator with an electronically controlled valve system. The controller receives temperature signals and actively controls the bypass valve opening, substituting passive thermal expansion mechanics with active electronic control. This increases control precision and timing accuracy while maintaining acceptable system complexity through integrated control logic
Solution Approach 2:
The controller can predict when bypass operation will be needed based on monitored parameters and proactively adjusts the bypass valve before critical overheating occurs. This preliminary action prevents boiling damage while optimizing engine warm-up by timing the bypass activation at the most appropriate moment, rather than relying on delayed thermal expansion response
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 prevents boiling damage in the exhaust heat recovery system while rapidly warming up the powertrain, improving fuel efficiency and reducing the need for additional heating systems, thus decreasing harmful emissions and installation costs.
Implementation Method 1
The exhaust heat recovery system is configured such that the coolant and exhaust gas can exchange heat, allowing the coolant to absorb heat from the exhaust gas and heat the coolant
Implementation Method 2
a drive motor actuator, which regulates coolant distribution
Data Source
AI summary
A system for controlling coolant of a vehicle can include an integrated flow control valve configured to open and close branch lines for supplying coolant discharged from an engine of the vehicle to an automatic transmission fluid (ATF) warmer, a heater, and a radiator, respectively, an exhaust heat recovery system configured to exchange heat between exhaust gas discharged from the engine and the coolant discharged from the engine, and a controller configured to control the integrated flow control valve to open and close the branch lines to supply coolant to the ATF warmer, heater, and radiator, respectively, depending on the temperature of the outside air, the coolant temperature discharged from the engine, and the coolant temperature discharged from the exhaust heat recovery system, and control the exhaust heat recovery system to allow heat exchange between the exhaust gas and the coolant.