Seat Heater Impedance Sweep for Occupancy Detection
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Solution Overview
Problem
Existing heating systems in trains require excessive energy consumption to heat the entire interior, and there is a need for cost-effective seat occupancy detection to optimize passenger flow and stop times.
Innovation Solution
A method using a seat heater with elongated heating elements applies an alternating voltage frequency sweep between 10 MHz to 40 MHz to determine seat occupancy by comparing the amplitude curve with a reference curve, distinguishing between human presence and luggage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If decentralized heating coils with air flow are used to heat the interior, then the entire interior can be heated, but excessive energy is consumed
Solution Approach 1:
The patent implements local heating by equipping individual seats with heating elements instead of heating the entire train interior. Each seat heater provides thermal energy only to its specific location, eliminating the waste of heating empty areas. This localized approach directly reduces overall energy consumption while maintaining passenger comfort.
Solution Approach 2:
The heating system is segmented into multiple independent seat heaters, each capable of operating autonomously. This segmentation allows the system to activate only the seats that are occupied, rather than heating the entire interior space uniformly. The modular structure enables precise control of thermal energy distribution.
2Ease of manufacture
If seat heating is implemented without additional cabling, then installation cost is reduced, but occupancy detection capability is lost
Solution Approach 1:
The seat heater's electrical connections serve dual purposes: providing power for heating and enabling occupancy detection through impedance measurement. The same wiring harness that supplies heating current also carries the detection signals, eliminating the need for separate cabling while maintaining full functionality. This multi-use approach reduces installation complexity and cost.
Solution Approach 2:
The heating function and occupancy detection function are merged into a single integrated system. The electrical connections and control circuitry for both functions are combined, allowing the system to perform both heating and detection tasks through shared components. This integration eliminates redundant cabling and reduces overall system complexity.
3Ease of operation
If a single frequency alternating voltage is applied to the heating device, then the system is simple to operate, but occupancy detection precision is insufficient
Solution Approach 1:
The system transitions from using a single static frequency to dynamically sweeping through a range of frequencies (10 MHz to 40 MHz). This frequency sweep allows the system to capture the impedance characteristics of the seat across multiple frequency points, providing more data for accurate occupancy detection while maintaining relatively simple operation through automated frequency modulation.
Solution Approach 2:
The system changes the frequency parameter of the applied voltage across a defined range rather than maintaining a fixed frequency. By measuring impedance at multiple frequency points during the sweep, the system gathers more information about the seat's electrical characteristics, improving occupancy detection precision. The automated frequency variation is managed by control circuitry, keeping operation simple.
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
Efficiently determines seat occupancy with minimal additional cabling, allowing for precise detection and reduced energy consumption, and optimizing train operations by providing real-time occupancy data.
Implementation Method 1
a heating device with a plurality of, in particular elongated, heating elements and with a first and a second connection... a power supply and control device for supplying the heating device with heating energy by applying a heating current
Implementation Method 2
The detection device is designed and configured to apply an alternating voltage in order to determine the occupancy status of the seat
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
Method for determining the occupancy status of a seat (5) by means of a seat heater (10) provided in the seat, which has a heating device (20) with several heating elements (25) and a first (21) and a second connection (22). The method is further developed in that an alternating voltage with a frequency range of 10 MHz to 40 MHz or a subrange thereof is applied to the heating device (20) to determine the occupancy status. The amplitude profile of the voltage (51) is then determined via the two connections (21, 22) over the frequency sweep and compared with a reference profile (50).