NOx Sensor Cover Angled Openings Water Ingress
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Solution Overview
Problem
NOx sensors in internal combustion engines are exposed to weather conditions, such as rain, which can lead to water droplets entering the turbine casing and potentially causing degradation of the sensor element, especially when it is heated, affecting the accuracy and longevity of emissions data.
Innovation Solution
A cover is designed for the NOx sensor with angled openings to admit exhaust gases, including a first opening normal to gravity and a second opening angled to gravity, which disrupts water droplet flow while maintaining a desired exhaust gas flow rate, thereby protecting the sensor from water ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensor is exposed to exhaust gases for accurate sensing, then measurement precision is improved, but water droplets can enter and cause degradation
Solution Approach 1:
The cover is divided into multiple openings with different orientations (first opening normal to gravity, second opening angled to gravity). Each opening serves a specific function: the first allows exhaust gas flow while the second is specifically designed to disrupt water droplet flow paths, preventing them from reaching the sensor element.
Solution Approach 2:
The cover acts as an intermediary component between the exhaust gas stream and the sensor element. It selectively admits exhaust gases while blocking water droplets, mediating the interaction between the harsh environment and the sensitive sensor to protect it from harmful factors.
2Reliability
If the cover blocks water droplets completely, then reliability is improved, but exhaust gas flow may be restricted
Solution Approach 1:
Different regions of the cover have different functional qualities. The first opening is optimized for exhaust gas admission with a orientation normal to gravity, while the second opening is specifically designed with an angle to gravity to disrupt water droplet flow. This local differentiation allows the cover to selectively admit gases while blocking liquids without restricting overall exhaust flow.
Solution Approach 2:
The solution addresses the water blocking function by changing the dimensional orientation of the second opening relative to gravity, rather than simply reducing opening size. By angling the second opening, water droplets following gravity-driven paths are disrupted, while exhaust gases can still pass through, maintaining flow rates while improving protection.
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
The cover effectively reduces the exposure of the NOx sensor to water droplets, ensuring the sensor's integrity and maintaining accurate emissions data by directing exhaust gases while preventing large water droplets from reaching the sensor.
Implementation Method 1
a first opening configured to admit exhaust gases in a first direction normal to gravity and a second opening configured to admit exhaust gases in a second direction angled to gravity
Implementation Method 2
disrupts water droplet flow while maintaining a desired exhaust gas flow rate
Data Source
AI summary
Systems are provided for a sensor. In one example, a system includes a cover for a sensor mounted in a turbine casing, wherein the cover comprises a first opening configured to admit exhaust gases in a first direction normal to gravity and a second opening configured to admit exhaust gases in a second direction opposite gravity.