Gas Sensor Deflector Accelerates Flow for Sensitivity
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Solution Overview
Problem
Existing gas sensors in internal combustion engines, particularly nitrogen oxide sensors, face reduced sensitivity due to low gas flow velocity, affecting their ability to accurately measure gas properties and trigger necessary processes like trap regeneration.
Innovation Solution
The implementation of a sensor design featuring deflectors arranged around the sensor body to accelerate gas flow, reducing the flow area and guiding gases through the space between the body and deflectors, thereby increasing gas flow velocity and sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sensor is placed in the exhaust circuit to measure gas properties, then the sensor can detect gas concentration, but the gas flow velocity around the sensor is too low which reduces sensitivity
Solution Approach 1:
The patent employs curved deflector surfaces that guide the gas flow around the sensor body. The curved geometry of the deflectors creates a streamlined flow path that accelerates the gas toward the sensor while maintaining smooth flow conditions, thereby increasing the gas flow velocity at the sensor location without causing turbulence or flow separation.
Solution Approach 2:
The patent introduces deflectors positioned perpendicular to the main gas flow direction, effectively adding a dimensional element to the flow control. These deflectors, extending in the radial direction, create a three-dimensional flow acceleration zone that channels gas from multiple directions toward the sensor, increasing the effective flow velocity at the measurement point.
2Device complexity
If the sensor body is mounted perpendicular to the gas flow direction, then the sensor structure is simplified, but the flow area is not reduced which limits flow acceleration
Solution Approach 1:
The patent divides the sensor assembly into distinct functional components: the sensor body mounted perpendicular to the flow for structural simplicity, and separate deflector elements positioned around the sensor. This segmentation allows the deflectors to independently control the flow area and accelerate the gas, while the sensor body maintains its simplified perpendicular mounting configuration.
Solution Approach 2:
The deflectors serve as intermediary elements between the main gas flow and the sensor body. These intermediaries reduce the effective flow area in a controlled manner, accelerating the gas before it reaches the sensor, while allowing the sensor body to maintain its simple perpendicular mounting without directly interfering with the flow path.
3Measurement precision
If deflectors are added to accelerate gas flow, then sensitivity increases, but device complexity increases
Solution Approach 1:
The patent merges the deflectors with the sensor housing or mounting structure, creating an integrated assembly. This combining of elements reduces the number of separate components and simplifies the overall device structure, while still providing the necessary flow acceleration function. The deflectors are positioned and configured to work in conjunction with the sensor body as a unified system.
Solution Approach 2:
The deflectors are designed to perform multiple functions: they accelerate the gas flow toward the sensor, guide the flow in a controlled path, and potentially protect the sensor from direct exposure to high-velocity or particulate-laden gas. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device 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
This design significantly enhances the sensitivity and precision of gas property measurements, achieving a gas flow velocity gain of over 40% and improving measurement accuracy and uniformity, while maintaining low manufacturing costs.
Implementation Method 1
the at least one deflector being formed by a wall adapted to induce an acceleration of a gas flow at the level of the sensor... capable of reducing the flow area of a gas at the sensor to increase the gas flow rate at the sensor
Data Source
Figure 1
Figure 2~3
Figure 4a~4b
AI summary
A gas property measurement sensor, comprising a body (10) extending along a principal axis (z), intended for mounting perpendicular, or substantially perpendicular, to a direction of gas flow (x), characterized in that the sensor comprises at least one deflector (31, 32) disposed near the body (10) and surrounding at least part of the body, the at least one deflector being formed by a wall adapted to induce an acceleration of a gas flow at the level of the sensor.