Capacitive Sensor Pulse Evaluation for Low-EMI Vehicle Activation
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Solution Overview
Problem
Capacitive sensor devices in vehicles face challenges with high energy consumption and susceptibility to electromagnetic interference, making them complex and expensive to improve.
Innovation Solution
The solution involves a circuit arrangement that uses repeated charge transfers with a predetermined number of pulses to determine the state of charge, which is proportional to the sensor capacitance, reducing interference and allowing flexible adjustment of evaluation frequency and energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional charge transfer methods are used to detect capacitance changes, then the sensor can detect activation actions, but the energy consumption becomes problematic and electromagnetic interference increases
Solution Approach 1:
The patent implements periodic charge transfer cycles where the sensor electrode is repeatedly charged and discharged through controlled switching. This periodic operation allows capacitance measurement to be performed in discrete time intervals rather than continuously, significantly reducing energy consumption while maintaining detection capability. The evaluation unit performs multiple charge transfers in sequence, evaluating the state of charge after each cycle to determine capacitance changes.
2Reliability
If conventional charge transfer methods are used to detect capacitance changes, then the sensor can detect activation actions, but electromagnetic interference (immission and emission) increases
Solution Approach 1:
By using periodic charge transfer cycles with controlled duration and frequency, the patent limits electromagnetic interference to specific time intervals rather than continuous operation. This allows other vehicle systems to operate without interference and reduces the overall electromagnetic burden on the vehicle's electrical environment.
Solution Approach 2:
The evaluation unit acts as an intermediary between the sensor electrode and the vehicle's control systems. It processes the charge transfer signals in a controlled manner, filtering and evaluating the capacitance changes before triggering any vehicle functions. This intermediary processing reduces the direct electromagnetic impact on the vehicle's electrical systems.
3Measurement precision
If the number of charge transfers is increased to improve measurement accuracy, then detection reliability improves, but energy consumption and evaluation time increase
Solution Approach 1:
The evaluation unit performs a predetermined number of charge transfer cycles in sequence, evaluating the state of charge after each cycle. This periodic evaluation approach allows the system to achieve measurement precision through multiple samples while maintaining control over the total evaluation time. The process can be interrupted or adjusted based on the detected state, optimizing the balance between precision and time.
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 significantly reduces interference and emission, while also enhancing the reliability of detection and reducing energy consumption, allowing for cost-effective implementation.
Implementation Method 1
a variable capacitance can be generated by means of a sensor element such as a sensor electrode, which is specific to changes in the environment of the sensor electrode
Implementation Method 2
an electrical holding arrangement which is connected to the sensor element for charge transfer
Data Source
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AI summary
The invention relates to an arrangement (10) for evaluation in a capacitive sensor device (20) of a vehicle (1), in particular for detecting an activation action in the vehicle (1), comprising: - at least one sensor element (20.1) for detecting a change in the environment of the sensor element (20.1), - an electrical holding arrangement (50.4) which is connected to the sensor element (20.1) for charge transfer, - a control device (50) for repeatedly determining (100) at least one parameter of the sensor element (20.1) specific for detection in order to carry out the evaluation, - at least one control means (50.6) of the control device (50) in order to repeatedly carry out the charge transfer as pulses (P) with a predetermined number (N) for the respective determination (100) of the parameter, so that a charge state of the holding arrangement (50.4) is successively changed.