Air Flow Sensor Integrating Multi-Sensor Module for Humidity
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Solution Overview
Problem
Conventional air flow rate measuring devices require additional temperature sensors to accurately measure intake air temperature, leading to increased complexity and measurement errors due to indirect contact and heat transfer issues, which affect the calculation of absolute humidity.
Innovation Solution
An air flow rate measuring device with a multi-sensor unit protruding from the casing, integrating relative humidity and temperature sensors, positioned directly within the intake air passage to avoid heat transfer from the casing, allowing direct detection of intake air temperature and relative humidity, eliminating the need for a dedicated temperature sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a humidity sensor with relative humidity detector and first temperature detector is provided to calculate absolute humidity, then the absolute humidity calculation function is achieved, but the number of components increases and device complexity increases
Solution Approach 1:
The patent combines the first temperature detector (for absolute humidity calculation) and the second temperature detector (for direct intake air temperature measurement) into a single integrated sensor module. This merging reduces the number of separate components and connections while maintaining both measurement functions, directly resolving the contradiction between measurement capability and device complexity
Solution Approach 2:
The integrated sensor module serves multiple functions: it provides both the first temperature signal and second temperature signal, and also includes the relative humidity detector. This multi-functional design eliminates the need for separate dedicated temperature sensors and reduces the overall component count while achieving comprehensive measurement capabilities
2Device complexity
If the first temperature detector is arranged where intake air is not directly contacted, then the device structure is simplified, but the temperature detection accuracy deteriorates
Solution Approach 1:
The patent uses the bypass passage as an intermediary structure that allows intake air to flow close to the first temperature detector without direct contact, while still enabling accurate temperature measurement. The bypass passage mediates between the need for simplified structure and accurate temperature detection by creating a controlled thermal environment
3Device complexity
If the relative humidity detector is arranged where intake air is not directly contacted, then the device structure is simplified, but the relative humidity detection accuracy deteriorates
Solution Approach 1:
The bypass passage serves as an intermediary that allows the relative humidity detector to be positioned in a simplified structural location while still exposing it to intake air conditions. The bypass passage mediates the thermal and humidity environment to the detector without requiring direct intake air contact
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 configuration enables accurate measurement of intake air temperature and calculation of absolute humidity without additional sensors, reducing device complexity and improving measurement accuracy, while maintaining advanced engine control capabilities.
Implementation Method 1
a flow rate sensor that detects a flow rate of the intake air by heat transfer with the intake air
Implementation Method 2
The multi-sensor unit is exposed to the inside of the intake air passage... allowing direct detection of intake air temperature
Implementation Method 3
The air flow rate measuring device includes a multi-sensor unit that detects a relative humidity and a temperature of an intake air flowing through the intake air passage
Data Source
AI summary
The present disclosure provides an air flow rate measuring device disposed in an intake air passage. The air flow rate measuring device measures a flow rate of the intake air flowing through the intake air passage. The air flow rate measuring device includes a casing, a flow rate sensor, and a sensor module. The casing defines a bypass passage to take in a portion of the intake air. The flow rate sensor is disposed in the bypass passage. The flow rate sensor generates an output signal according to a flow rate of the intake air. The sensor module protrudes from an outer wall of the casing. The sensor module includes a multi-sensor unit that has a relative humidity sensor and a temperature sensor. The relative humidity sensor is exposed to an inside of the intake air passage to detect a relative humidity of the intake air flowing through the intake air passage. The temperature sensor detects a temperature of the intake air flowing through the intake air passage.