Vehicle Heating Electrode Duty Cycle for Proximity Sensing
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Solution Overview
Problem
Existing occupant sensor systems face challenges in reliably detecting the presence of a vehicle occupant near heating elements due to electrical coupling issues between electrodes and heating elements, leading to inaccurate proximity sensing.
Innovation Solution
A vehicle component heating system that incorporates a computer, electrode, and processor to control a duty cycle for an electrical power signal, which includes heating, sensing, and idle periods, allowing the electrode to both generate heat and sense proximity while minimizing parasitic capacitance through strategic signal management and shielding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an electrode is positioned close to a heating element to sense occupant proximity, then sensing sensitivity is improved, but electrical coupling between the electrode and heating element increases causing unreliable detection
Solution Approach 1:
The system applies periodic heating signals and sensing signals alternately through the electrode. The heating signal activates the heating element during heating periods, while the sensing signal is applied during sensing periods to measure capacitance changes. This periodic alternation prevents continuous electrical coupling interference while maintaining both heating and sensing functions.
Solution Approach 2:
The system performs preliminary sensing to detect occupant presence before activating heating. The controller first applies a sensing signal to detect capacitance changes indicating occupant proximity, and only after confirming occupancy does it activate the heating signal. This preliminary detection prevents false heating activation and improves sensing reliability.
2Device complexity
If the electrode serves both heating and sensing functions, then device complexity is reduced, but the ability to reliably perform both functions simultaneously becomes compromised
Solution Approach 1:
The electrode alternates between heating mode and sensing mode through periodic signal application. During heating periods, the heating signal is applied to warm the occupant; during sensing periods, the sensing signal is applied to detect capacitance changes. This time-division multiplexing allows a single electrode to reliably perform both functions without continuous interference.
Solution Approach 2:
The system dynamically switches the electrode's function based on real-time conditions. The controller adjusts whether the electrode is in heating mode or sensing mode based on occupancy detection, temperature requirements, and system state. This dynamic switching enables the single electrode to adaptively perform the most appropriate function at each moment.
3Temperature
If continuous heating is applied to maintain occupant comfort, then occupant warmth is improved, but energy consumption increases and sensing capability is reduced
Solution Approach 1:
The system continuously monitors temperature and occupancy conditions and adjusts heating accordingly. When an occupant is detected and the component temperature is below the comfort threshold, heating is activated. When the temperature reaches the threshold or no occupant is present, heating is reduced or stopped. This feedback control maintains comfort while minimizing energy consumption.
Solution Approach 2:
The system maintains continuous temperature monitoring and adjusts heating in real-time to ensure continuous occupant comfort. Rather than applying fixed continuous heating, the system continuously adapts the heating level based on current temperature and occupancy conditions, ensuring useful heating action only when needed.
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 system effectively heats vehicle components while accurately sensing occupant proximity, improving reliability and reducing costs by integrating heating and sensing functions into a single electrode, thus enhancing the occupant's comfort and the vehicle's operational efficiency.
Implementation Method 1
The electrode is for generating heat for a surface of the vehicle component within the sensing zone in response to receiving the heating signal
Implementation Method 2
the electrical coupling between the electrode and the heating element may be greater than the electrical coupling between a vehicle occupant and the electrode
Data Source
AI summary
Various implementations include a vehicle component heating system that includes an electrode disposed within a sensing zone, and a processor. The electrode generates heat for a surface of a vehicle component within the sensing zone and senses proximity of an occupant to the sensing zone. The processor selects a heating percentage of a duty cycle for generating a heating signal, a sensing percentage of the duty cycle for generating and measuring a sensing signal and reporting the measured sensing signal, and an idle percentage of the duty cycle during which neither the heating nor the sensing signal is generated, wherein the sum of the heating, sensing, and idle percentages is 100%. The processor generates the heating signal and/or generates and measures the sensing signal and reports the measurement of the sensing signal based on the selected percentages.