Adjustable A/D Input Low-Pass Filter for Multi-Sensor Vehicle Control
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Solution Overview
Problem
Existing vehicle controllers face challenges in processing input signals with different frequency ranges at a single input terminal, requiring different cut-off frequencies for various vehicle systems, which is not effectively addressed by current technologies.
Innovation Solution
An engine control module with an adjustable low-pass filter is introduced, featuring a resistor, capacitors, and controllable switches that allow for multiple cut-off frequencies, enabling the module to be configured for different sensors with varying dynamic ranges by selectively activating capacitors to filter input signals before they are processed by an analog-to-digital converter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single fixed cut-off frequency filter is used at the input terminal, then the circuit design is simple, but the controller cannot process input signals with different frequency ranges from different sensors
Solution Approach 1:
The patent implements a dynamic filter by making the cut-off frequency adjustable through capacitor switching. The filter transitions from a static fixed-frequency design to a dynamic multi-frequency design where capacitors can be selectively connected or disconnected to change the filter characteristics in real-time, allowing adaptation to different sensor frequency ranges.
Solution Approach 2:
The patent creates a universal filter circuit that can handle multiple frequency ranges by incorporating multiple capacitors (C1, C2, C3) that can be selectively activated. This single filter circuit serves multiple functions by adapting its cut-off frequency to match different sensor requirements, eliminating the need for separate filters for each sensor type.
2Measurement precision
If multiple fixed cut-off frequency filters are provided for different sensors, then each sensor can be optimized, but the device complexity and number of components increase
Solution Approach 1:
The patent implements a universal filter circuit that can serve multiple sensor types by incorporating capacitor switching functionality. Instead of providing separate dedicated filters for each sensor, a single multi-functional filter circuit is created that can be configured to optimize filtering for different sensor frequency ranges through selective capacitor activation.
Solution Approach 2:
The patent transforms multiple static filter circuits into a single dynamic filter circuit. By using controllable switches to dynamically connect or disconnect capacitors C1, C2, and C3, the system achieves multiple filtering characteristics from one circuit, reducing component count while maintaining the ability to optimize signal filtering for different sensors.
3Measurement precision
If the cut-off frequency is adjusted to match sensor dynamic range, then signal processing accuracy is improved, but the filter configuration becomes more complex
Solution Approach 1:
The patent implements a self-service filter configuration system where the control circuitry automatically selects and activates the appropriate capacitors based on the sensor type and required frequency range. Instead of requiring manual configuration, the system self-adjusts by having the controller identify the needed cut-off frequency and automatically switch the corresponding capacitors into the circuit.
Solution Approach 2:
The patent incorporates feedback mechanisms where the control circuitry monitors the input signal characteristics and sensor requirements, then automatically adjusts the filter configuration by switching capacitors accordingly. This closed-loop approach ensures the filter is always optimally configured for the current operating conditions without manual intervention.
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 solution allows the engine control module to efficiently process input signals across different frequency ranges, ensuring accurate control of vehicle systems by adjusting cut-off frequencies based on the sensor dynamic range, thereby enhancing the module's versatility and performance.
Implementation Method 1
The adjustable low-pass filter includes a resistor, a first capacitor, a second capacitor, and a first controllable switch coupled to the first capacitor
Implementation Method 2
The first controllable switch is selectively turned on to conduct the first capacitor to cause the adjustable low-pass filter to provide either the first cut-off frequency or the second cut-off frequency
Data Source
AI summary
An engine control module comprises an input terminal configured to receive an input signal, an analog-to-digital converter configured to receive the input signal from the input terminal, control circuitry configured to receive the input signal from the analog-to-digital converter and to control at least one engine output based on the input signal, and an adjustable low-pass filter. The adjustable low-pass filter is coupled between the input terminal and the analog-to-digital converter such that the analog-to-digital converter receives the input signal from the input terminal via the adjustable low-pass filter. The adjustable low-pass filter is configured to filter the input signal from the input terminal prior to the input signal being applied to the analog-to-digital converter. The adjustable low-pass filter has a first setting in which the adjustable low-pass filter has a first cut-off frequency and a second setting in which the adjustable low-pass filter has a second cut-off frequency, wherein the first setting configures the engine control module to be used with a first sensor having a first dynamic range and the second setting configures the engine control module to be used with a second sensor having a second dynamic range.