Gas Sensor Double Squeezing Structure Clogging Prevention
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Solution Overview
Problem
The fluctuating air flow rate and pulsation in the air intake passage of internal combustion engines affect the detection accuracy of gas concentration sensors, leading to clogging issues and reduced responsiveness due to particles and droplets in the gas intake port.
Innovation Solution
A gas sensor apparatus with a double squeezing structure, featuring a gas intake port and a communicating portion, where the air flow expands in two stages between the intake port, expansion chamber, and measurement chamber, reducing air movement and increasing the intake port capacity to minimize clogging and maintain detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the capacity of the gas intake port is decreased to reduce air flow fluctuations, then the air flow stability improves, but particles or droplets clog the gas intake port causing responsiveness to decrease
Solution Approach 1:
The patent divides the gas intake path into two separate ports: a first gas intake port for introducing air to the expansion chamber, and a second gas intake port for introducing air to the measurement chamber. This segmentation allows each port to be optimized independently - the first port can be larger for better flow stability while the second port remains smaller to prevent clogging, resolving the contradiction between flow stability and responsiveness.
2Productivity
If the capacity of the gas intake port is increased to prevent clogging, then the responsiveness improves, but the air flow fluctuations and pulsation increase deteriorating detection accuracy
Solution Approach 1:
By segmenting the gas intake function into two separate ports, the system can have a larger first gas intake port that prevents clogging and maintains responsiveness, while the smaller second gas intake port limits air flow fluctuations entering the measurement chamber, thereby maintaining detection accuracy despite increased overall intake capacity.
3Measurement precision
If the measurement chamber is disposed closer to the center of the passage to prevent heat transmission, then the temperature measurement accuracy improves, but the gas intake efficiency decreases
Solution Approach 1:
The patent uses two separate gas intake ports positioned at different locations - the first port can be positioned for optimal gas intake efficiency while the second port is positioned to supply the measurement chamber. This allows the measurement chamber to be positioned centrally for temperature accuracy without compromising overall gas intake efficiency, as the first port compensates for the reduced intake efficiency at the second port location.
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 design enhances measurement accuracy and responsiveness by reducing air movement in the measurement chamber and minimizing clogging from particles and droplets, even in contaminated environments.
Implementation Method 1
a second cavity portion provided between the first cavity portion and the gas intake port, wherein a volume of air flowing from the gas intake port to the measurement chamber expands in two stages
Implementation Method 2
The thermal concentration sensor element uses a difference in thermal conductivity of gas according to the concentration of the gas. The thermal concentration sensor element measures the concentration based on variations of a resistance value generated from a difference in heat radiation amount radiated into the atmosphere from a heated resistor
Data Source
AI summary
To provide a gas sensor apparatus capable of preventing clogging of a gas intake port due to particles, droplets, or the like, of a gas and maintaining measurement accuracy for a long time, a gas sensor apparatus 1 includes a housing 3. The housing 3 includes an expansion chamber 6 communicating with an air intake passage 2 via an air intake port 8, and a measurement chamber 5 communicating with the expansion chamber 6 via a communicating portion 7. A double squeezing structure including the gas intake port 8 and the communicating portion 7 is provided, and two stages of regions where the volume expands between the gas intake port 8 and the measurement chamber 5 are provided. As a result, the movement of the air in the measurement chamber 5 is decreased. It is possible to provide a structure in which the capacity of the gas intake port 8 is increased to avoid clogging of the gas intake port due to particles or droplets.