Water Ingress Detection via Dew Point Monitoring
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for detecting water ingress into sealed housings, such as those in electric bicycles, are inadequate for rapid and reliable detection, especially in environments prone to mechanical damage and humidity changes, which can lead to condensation and damage to electronic components.
Innovation Solution
A method utilizing temperature and humidity sensors to detect water ingress by calculating the difference between the detected temperature and dew point, and monitoring the change rate of this difference, allowing for early detection of even small water quantities and triggering adaptive responses like current adjustments and service alerts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polymer seals are used to seal the housing against water ingress, then the housing is protected from water, but the seals are susceptible to mechanical damage and material fatigue over time
Solution Approach 1:
The patent applies preliminary action by detecting water ingress at an early stage through humidity and temperature sensors before the seals fail completely. The system monitors the interior environment continuously and triggers alerts or protective measures when water penetration is detected, allowing for timely intervention before mechanical damage or material fatigue progresses to seal failure.
2Ease of operation
If the housing is installed at the crankshaft for better weight distribution, then the electric bicycle has improved weight distribution and riding experience, but the housing becomes more exposed to water spray and mechanical damage
Solution Approach 1:
The patent implements feedback by continuously monitoring the interior environment of the housing with humidity and temperature sensors. When water ingress is detected through changes in humidity levels or dew point calculations, the system provides immediate feedback via alerts to the user or activation of protective measures, enabling real-time response to water exposure without compromising the optimal crankshaft installation position.
3Device complexity
If simple humidity detection is used, then the detection system is simple, but it cannot reliably distinguish between normal humidity changes and actual water ingress
Solution Approach 1:
The patent applies parameter changes by using both humidity and temperature measurements to calculate dew point and analyze the relationship between these parameters. Instead of relying on a single humidity threshold, the system evaluates multiple parameters (relative humidity, temperature, dew point temperature) and their interrelationships to distinguish between normal humidity variations and actual water ingress, significantly improving detection accuracy while maintaining reasonable system complexity.
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 rapid and reliable detection of water ingress, preventing damage to electrical components and facilitating timely maintenance and repair, thereby reducing long-term damage and ensuring the integrity of the housing.
Implementation Method 1
A relative air humidity φ is a ratio of absolute air humidity ρ to maximally possible mass of water vapor ρmax in the air or the ratio of the partial pressure of water vapor ew to its saturation vapor pressure esat according to equation (2). Relative air humidity φ may be detected or measured with the aid of a humidity sensor, for example by absorbing water within a porous polymer matrix, thus changing a dielectric constant.
Implementation Method 2
The method according to the present invention includes a detection of a temperature in the interior of the housing. The temperature detection preferably takes place with the aid of a temperature sensor, which is situated in the interior.
Implementation Method 3
Dew point τ is a function of the partial pressure of water vapor ew according to equation (4), C1, C2, and C3 being the temperature-sensitive constants.
Data Source
AI summary
A method for detecting a water ingress into an interior of a housing, which is sealed against the surroundings, including the following steps: detecting a temperature of the air in the interior; detecting a relative air humidity in the interior; and detecting a water ingress as a function of the detected temperature and of the detected relative air humidity.