Switchable Vehicle Pane Temperature Sensing via Discharge Curve
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Solution Overview
Problem
Existing methods for determining the temperature of switchable glass panes in vehicles are costly and disruptive to operation, and temperature sensors installed on the glass panes do not accurately represent the temperature of the variable-transparency layer, leading to incorrect light transmission.
Innovation Solution
A method involving applying a reference voltage to the contact layers of the switchable pane, disconnecting one layer, and measuring the discharge curve through the variable-transparency layer to determine the temperature, using the time constant of the discharge as a parameter for temperature calculation, potentially aided by an existing vehicle temperature sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature sensors are installed in the switchable pane to measure temperature, then temperature measurement capability is improved, but material costs and cabling expenses increase
Solution Approach 1:
The switchable pane uses its own contact layers and variable-transparency layer to perform temperature measurement through electrical property characterization, eliminating the need for separate temperature sensors and their associated cabling. The system measures temperature by applying a test voltage and analyzing the discharge curve of the inherent capacitance, making the pane self-diagnostic for temperature.
Solution Approach 2:
The contact layers and variable-transparency layer serve dual functions: they control light transmission as the primary function and simultaneously enable temperature measurement as a secondary function. This multi-functionality eliminates the need for dedicated temperature sensing components.
2Ease of operation
If temperature sensors are placed at the edge of the glass pane, then installation is simplified, but temperature representation accuracy deteriorates
Solution Approach 1:
The measurement function is extracted from external sensors and integrated directly into the variable-transparency layer itself. By measuring the electrical discharge characteristics of the layer's inherent capacitance, the system obtains temperature data directly from the active material rather than inferring it from edge-mounted sensors.
Solution Approach 2:
The electrical discharge curve serves as an intermediary that links the physical temperature of the variable-transparency layer to measurable electrical parameters. The discharge time constant provides indirect but accurate temperature information without requiring direct thermal contact with external sensors.
3Measurement precision
If multiple independent temperature sensors are installed to improve temperature measurement accuracy, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The switchable pane's inherent electrical components (contact layers and variable-transparency layer forming a capacitor) perform temperature measurement without requiring external sensing devices. The system uses its own operational characteristics to self-diagnose temperature, eliminating the need for multiple independent sensors.
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
Enables precise, cost-effective, and non-disruptive temperature determination in situ, allowing for accurate control of light transmission across varying temperatures and vehicle conditions.
Implementation Method 1
Such materials change their optical properties, e.g. change from transparent to opaque and vice versa, when a voltage is applied to them.
Implementation Method 2
measuring a discharge curve, during which a first value for a temperature of the switchable pane is ascertained from a determined value for a parameter representing the discharge
Data Source
AI summary
Method for ascertaining a temperature of a variable-transparency, switchable pane which has a variable-transparency layer which, in order to switch said pane, is arranged between two transparent electrically conductive contact layers, comprising: applying an electrical reference voltage to the two contact layers; disconnecting one of the contact layers from the provided reference voltage at a predetermined first time; measuring a value of the residual voltage still remaining between the two contact layers during a discharge of the two contact layers through the variable-transparency layer during at least one second time which follows the predetermined first time and is temporally spaced apart from said first time; determining from the measurement a value of a parameter representing the discharge; and ascertaining a first value of the temperature of the switchable pane from the determined value for the parameter on the basis of an association rule between the parameter and the temperature by means of a control unit.