Exhaust Gas Sensor Icing Detection via Thermal Energy Balance
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Solution Overview
Problem
Existing methods for determining the icing condition of components in a motor vehicle's exhaust-gas system not directly in the exhaust-gas mass flow, such as differential pressure sensors, are inadequate as they do not provide precise information about the actual sensor temperature and mass flow, leading to incorrect engine control signals due to ice formation.
Innovation Solution
A method that determines the water quantity and state in components and feed lines, calculates the energy required for deicing and volatilization, and compares it with the energy supplied from radiated heat from components in the exhaust-gas mass flow, allowing for accurate identification of icing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dewpoint detection is performed using exhaust-gas mass flow and exhaust-gas temperature as input parameters, then icing condition can be detected, but the detection is not precise because it does not relate to the actual mass flow to the sensor and does not provide information relating to the actual sensor temperature
Solution Approach 1:
The patent implements feedback by continuously monitoring the actual sensor temperature and actual mass flow to the sensor, then using this feedback information to dynamically adjust the dewpoint detection calculations. This ensures the detection remains precise by constantly comparing actual conditions against the model predictions and correcting for deviations.
Solution Approach 2:
The differential pressure sensor system performs self-service by using its own measured data (actual temperature and actual mass flow) to determine its own icing condition. The sensor's inherent measurements feed into the dewpoint detection algorithm, allowing the system to self-diagnose without requiring external reference measurements.
2Ease of operation
If components connected to the exhaust-gas system via connecting lines are used, then the system can function, but these components can freeze and cannot send valid data
Solution Approach 1:
The patent applies preliminary action by proactively detecting icing conditions before they cause complete sensor failure. The dewpoint detection algorithm identifies when ice formation is occurring, allowing the control system to take corrective actions (such as heating the sensor or flagging data as invalid) before the sensor completely freezes over and loses functionality.
Solution Approach 2:
The patent converts the harmful effect of ice formation into a beneficial diagnostic opportunity. By monitoring the thermal and flow characteristics, the system detects ice formation and uses this information to adjust operations, turning a potential failure mode into a detectable and manageable condition that improves overall system reliability.
3Reliability
If pressure sensors are used to calculate pressure drop and compare with threshold value, then ice formation in tubular elements can be detected, but this method does not provide precise information for components not arranged directly in the exhaust-gas mass flow
Solution Approach 1:
The patent changes the detection parameters from simple pressure drop measurements to a multi-parameter dewpoint detection system that incorporates actual sensor temperature, actual mass flow to the sensor, and calculated dewpoint temperature. This parameter expansion provides the precision needed for components not directly in the exhaust-gas mass flow by capturing the thermal and flow conditions specific to each sensor's location.
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 method provides precise information on icing conditions, enabling the engine control unit to suppress erroneous signals and improve engine performance by ensuring accurate data from differential pressure sensors, enhancing diagnostics and control precision.
Implementation Method 1
determining an energy quantity supplied for deicing and for volatilization by means of the radiated heat from components arranged directly in the exhaust-gas mass flow
Implementation Method 2
determining an energy quantity required for deicing and for volatilizing the water quantity actually present in the component and in the feed line
Implementation Method 3
determining an energy quantity required for deicing and for volatilizing the water quantity actually present in the component and in the feed line
Data Source
AI summary
The disclosure relates to a method for determining the icing condition of a component of the exhaust-gas system of a motor vehicle that is not arranged directly in the exhaust-gas mass flow and/or of the feed line of the component. The method includes: determining a water quantity actually present in the component and in the feed line thereof and the state of aggregation of the water quantity; determining an energy quantity required for deicing and for volatilizing the water quantity; and determining an energy quantity supplied for deicing and for volatilizing the water quantity by radiated heat from components arranged directly in the exhaust-gas mass flow of the exhaust-gas system of the motor vehicle to the surroundings. The method also includes determining the icing condition of the component by comparing the energy quantity supplied for deicing and for volatilization with the energy quantity required for deicing and for volatilization.