Humidity Sensor Self-Diagnosis via Adaptive Heating
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The humidity measurement device attached to an internal combustion engine's intake system faces challenges due to high temperatures causing self-destruction of the measurement element during diagnosis, and the accuracy is degraded due to contaminants and environmental changes, lacking reliable self-diagnosis and safety measures.
Innovation Solution
A humidity measurement device with a configuration that includes a measurement element of relative humidity placed in a sub-passage to prevent contaminant adhesion, a control system for reliable self-diagnosis, and a method to determine if changes are due to diagnosis or environmental factors, ensuring accurate temperature and humidity measurements by interposing an intermediate state between steady and diagnostic states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the measurement element of relative humidity is heated for self-diagnosis in a high-temperature environment, then the diagnosis function is activated, but self-destruction of the measurement element may occur
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the heating temperature and duration of the measurement element based on the ambient temperature detected by the temperature measurement element. When the ambient temperature is high, the heating temperature and/or duration are reduced to prevent self-destruction while still enabling diagnosis. This adaptive parameter adjustment resolves the contradiction between enabling self-diagnosis and preventing measurement element damage.
2Reliability
If the measurement element of relative humidity is heated in a high-temperature environment, then the diagnosis is performed, but the change in relative humidity is small and diagnosis accuracy is degraded
Solution Approach 1:
The patent uses parameter changes to optimize the heating conditions based on ambient temperature. By adjusting the heating parameters (temperature and duration) according to the detected ambient temperature, the system ensures that sufficient relative humidity change occurs even in high-temperature environments, thereby maintaining diagnosis accuracy while preventing measurement element damage.
3Adaptability or versatility
If the measurement element of relative humidity is exposed to contaminants in the air intake system, then the device can be attached to the intake system for fuel economy improvement, but measurement accuracy is degraded due to contaminant adhesion
Solution Approach 1:
The patent implements self-service through automatic self-diagnosis and self-cleaning functions. The system periodically performs self-diagnosis by heating the measurement element and detecting relative humidity changes. When contamination is detected, the system automatically cleans the measurement element surface, restoring measurement accuracy without requiring manual intervention. This enables the device to maintain long-term operational accuracy in the contaminant-prone intake system environment.
4Reliability
If an unexpected diagnosis is performed during steady state, then the diagnosis function is activated, but measurement accuracy of temperature and relative humidity is degraded
Solution Approach 1:
The patent applies dynamics by implementing dynamic state management that distinguishes between steady state and diagnostic state. The system uses an intermediate transition state to smoothly switch between normal measurement mode and self-diagnosis mode. During the transition, the system prepares for diagnosis by gradually adjusting conditions, ensuring that when diagnosis is performed, it does not abruptly degrade the accuracy of temperature and relative humidity measurements. This dynamic state management allows the system to maintain measurement accuracy while enabling diagnostic functionality.
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 highly reliable self-diagnosis even with contaminants or deteriorated elements, preventing measurement accuracy degradation and ensuring safe diagnosis by distinguishing between environmental changes and element failures, thus maintaining accurate temperature and humidity readings.
Implementation Method 1
a measurement element of relative humidity... to calculate a specific humidity
Implementation Method 2
a heating element provided near the measurement element of relative humidity... when the measurement element of relative humidity is heated
Implementation Method 3
a measurement element of temperature provided near the measurement element of relative humidity
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3
AI summary
The present invention obtains a humidity measuring device capable of performing self-diagnosis with high reliability. This humidity measuring device 20 has a diagnosis processing unit 25 for performing self-diagnosis by using gas temperatures and gas humidities before and after a gas in an ambient atmosphere to be measured is heat-controlled. The diagnosis processing unit has a diagnosis start determining unit 26 for determining whether the self-diagnosis can be started on the basis of an exchange state in the ambient atmosphere to be measured and the gas temperature and the gas humidity before the gas in the ambient atmosphere to be measured is heat-controlled, and a diagnosis continuation determining unit 28 for determining whether the self-diagnosis can be continued on the basis of the gas temperature and the gas humidity that are heat-controlled during the self-diagnosis.