Thermostatic Valve Control for Engine Sensor Failure
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Solution Overview
Problem
Existing methods for automatically controlling charge air and coolant temperatures in internal combustion engines do not adequately address sensor failures, which can lead to inadequate cooling and potential engine overheating.
Innovation Solution
A method where the charge air temperature controller is dominant in normal operation, switching to the coolant temperature limit controller if the charge air temperature sensor fails, and vice versa, with a complete opening of the thermostatic valve if both sensors fail to ensure maximum cooling capacity is maintained.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a map-controlled thermostatic valve is used to automatically control charge air temperature, then charge air temperature control is improved, but the system becomes vulnerable to sensor failures leading to inadequate cooling
Solution Approach 1:
The patent implements a backup control strategy that is prepared in advance for sensor failure scenarios. When the charge air temperature sensor fails, the system automatically switches to using the coolant temperature sensor as a substitute measurement basis, and when both sensors fail, it enters an emergency mode with fully open thermostatic valve. This beforehand cushioning ensures continuous cooling functionality despite sensor failures.
Solution Approach 2:
The control unit acts as an intermediary that monitors the functionality of temperature sensors and mediates between different control modes. It determines whether sensors are functional and switches between normal control mode (using charge air temperature), backup control mode (using coolant temperature), and emergency control mode (both sensors failed), ensuring seamless transition and maintaining system reliability.
2Reliability
If the thermostatic valve is completely opened to ensure maximum cooling capacity, then cooling reliability is improved, but the charge air temperature control precision deteriorates
Solution Approach 1:
The system dynamically adjusts the thermostatic valve opening based on sensor availability and operational mode. In normal mode, the valve is precisely controlled to maintain optimal charge air temperature. In emergency mode with both sensors failed, the valve is completely opened to ensure minimum cooling functionality. This dynamic adaptation balances precision and reliability based on actual system conditions.
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 approach effectively protects the engine from overheating by ensuring continuous cooling even in emergency situations, such as sensor failures, by adjusting the thermostatic valve's operation based on the operational mode and sensor availability.
Implementation Method 1
The switching state of the thermostatic valve is determined by a thermostatic operating element, for example, an expanding material element, which expands with increasing temperature of the coolant flow, so that the thermostatic valve opens, or contracts with decreasing temperature of the coolant flow, so that the thermostatic valve closes under spring tension.
Implementation Method 2
The temperature of the charge air cooler coolant flow in turn defines, via the temperature difference from the charge air temperature, the amount of heat extracted from the charge air in the charge air cooler.
Implementation Method 3
the amount of heat extracted from the charge air in the charge air cooler
Data Source
AI summary
A method for automatically controlling an internal combustion engine, where, during normal operation in a first controller mode, a charge air temperature controller is set as dominant for a map-controlled thermostatic valve for automatically controlling the charge air temperature (TLL), or, during normal operation in a second controller mode, a coolant temperature limit controller is set as dominant for the map-controlled thermostatic valve for automatically controlling the coolant temperature (TKM). If a charge air temperature sensor fails, the second controller mode is set with the coolant temperature limit controller dominant, and if a coolant temperature sensor fails, the first controller mode is set with the charge air temperature controller dominant.