Coolant Temperature Sensor Diagnostics via Segmented Heat Models
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Solution Overview
Problem
Existing diagnostic methods for engine coolant temperature sensors in exhaust gas heat recovery systems are inaccurate due to the inability to model coolant temperature at distinct locations within the system, leading to reduced accuracy in energy loss quantification and potential false detection of component degradation.
Innovation Solution
Implementing separate temperature models for coolant temperature computation at different locations in the exhaust gas heat recovery system, comparing measured temperatures to modeled temperatures to detect degradation of coolant temperature sensors, and incorporating heat loss calculations between vehicle components to improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single temperature model is used for computing coolant temperature at all locations in the EGHR system, then the device complexity is reduced, but the measurement precision and reliability of sensor degradation detection deteriorate
Solution Approach 1:
The patent divides the EGHR system into multiple distinct locations (upstream of heat exchanger, downstream of heat exchanger, and engine coolant inlet) and implements separate temperature models for each location. Each model accounts for local heat transfer characteristics and operating conditions, enabling precise temperature prediction at each specific point while maintaining manageable system complexity through modular modeling approach.
2Manufacturing precision
If energy loss during heat transfer is not quantified in the temperature model, then the manufacturing precision and model accuracy are reduced, but the ease of manufacture and implementation is improved
Solution Approach 1:
The patent incorporates energy loss quantification into the temperature models by comparing predicted temperatures with actual sensor measurements. The model uses feedback from temperature differences and heat transfer efficiency calculations to adjust and refine temperature predictions, thereby improving model accuracy while maintaining reasonable implementation complexity through iterative calibration.
3Reliability
If separate temperature models are implemented for different locations in the EGHR system, then the reliability of sensor degradation detection is improved, but the device complexity increases
Solution Approach 1:
The patent implements separate temperature models for each critical location in the EGHR system, allowing independent monitoring and degradation detection for each sensor. This segmentation enables the system to reliably identify which specific sensor may be degrading by comparing actual readings against location-specific predicted temperatures, while the modular structure keeps the overall diagnostic system manageable.
4Loss of information
If a single model is used for coolant temperature computation, then the loss of information about location-specific temperature variations is minimized, but the measurement precision at distinct locations deteriorates
Solution Approach 1:
The patent creates separate temperature models for each location (upstream of heat exchanger, downstream of heat exchanger, engine coolant inlet) to capture location-specific temperature variations. This segmentation preserves information about the temperature distribution throughout the EGHR system while providing precise temperature predictions at each distinct location, enabling accurate sensor performance evaluation.
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 allows for reliable and accurate diagnostics of coolant temperature sensors, reducing the propensity of coolant overheating and enhancing the robustness of the HVAC system by differentiating sensor degradation and reducing false detection of system components.
Implementation Method 1
exhaust heat may be recovered by coolant flowing through a heat exchanger of the EGHR system
Implementation Method 2
Coolant with the recovered exhaust heat may be circulated via the engine and/or the heater core
Data Source
AI summary
Methods and systems are provided for on-board diagnostics of components of an exhaust gas heat recovery (EGHR) system including engine coolant temperature sensors coupled to the system. Degradation of one or more of a first coolant temperature sensor coupled upstream of a heat exchanger of the EGHR system and a second coolant temperature sensor coupled downstream of the heat exchanger may be indicated based on a difference between a modeled coolant temperature and a measured coolant temperature, the modeled coolant temperature based on one or more of heat transfer between a heater core and vehicle cabin, and heat transfer between exhaust flowing via the heat exchanger and coolant flowing through the heat exchanger.