Passive In-Vehicle BrAC Sensing With Tracer Gas Validation
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Solution Overview
Problem
Existing breath alcohol detection technologies require drivers to perform forced expirations, which are inconvenient and can be affected by environmental conditions, making them inaccurate in various situations, such as high winds or hot weather, and can be defeated by drivers attempting to evade measurement.
Innovation Solution
A passive breath alcohol detection system that measures breath alcohol concentration from the air within a vehicle using a tracer gas and sensors, switching to an active test if conditions are not met, ensuring accuracy and convenience by continuously monitoring environmental and driver behavior parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a passive breath test is used to improve driver convenience, then ease of operation is improved, but measurement precision deteriorates under certain environmental conditions
Solution Approach 1:
The system dynamically switches between passive and active breath test modes based on real-time environmental condition monitoring. When conditions are favorable, passive mode provides convenience; when conditions deteriorate (high wind, hot weather), the system automatically transitions to active mode to maintain measurement precision.
Solution Approach 2:
Environmental sensors continuously monitor conditions and provide feedback to the control system. This feedback loop enables the system to detect when environmental factors compromise measurement accuracy and automatically adjust the testing mode accordingly, ensuring both convenience and precision are optimized based on current conditions.
2Measurement precision
If environmental monitoring parameters are increased to improve measurement accuracy, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The system employs a multi-functional sensor array where each sensor serves multiple purposes. For example, temperature sensors monitor both environmental conditions and sensor operating temperature, while pressure sensors detect both wind conditions and vehicle cabin pressure changes. This multi-functionality reduces the need for dedicated sensors for each parameter, thereby limiting complexity increase.
Solution Approach 2:
The system monitors changes in environmental parameters (temperature, pressure, humidity, wind speed) to detect conditions that affect measurement accuracy. By focusing on parameter changes rather than absolute values, the system can identify problematic conditions with simpler sensing requirements, reducing overall device complexity while maintaining precision.
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 convenient and accurate breath alcohol detection without requiring drivers to take directed breath samples, maintaining accuracy under various conditions and preventing system evasion, thereby ensuring safe vehicle operation.
Implementation Method 1
A sensor system measures a concentration of a tracer gas in a passively obtained air sample
Data Source
AI summary
Methods and apparatus allow for passive determination of a driver's Breath Alcohol Concentration (BrAC). Alcohol concentrations can be determined from exhaled breath, however inconvenience to a driver is often a barrier for incorporation of BrAC sensors into vehicles. The methods and apparatus allow for passive determination of a driver's BrAC, while detecting and accounting for a wide range of environmental conditions that may reduce the accuracy of a passive BrAC reading.