Exhaust Gas Sensor Inner Sleeve Throttling
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Solution Overview
Problem
Existing exhaust gas sensors face variability in sensitivity and dynamics due to orientation in exhaust gas lines, leading to inconsistent performance, especially when detecting soot particles, as the flow speed and direction affect particle deposition on the sensor element.
Innovation Solution
The design incorporates a sleeve-shaped sensor housing with a protective tube comprising an inner and outer protective sleeve, where the gas inlet of the inner protective sleeve forms the smallest flow cross section, creating a negative pressure that homogenizes exhaust gas flow and accelerates it towards the sensor element, regardless of sensor rotation, enhancing sensitivity and particle detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensor element is oriented perpendicular to the main flow direction in the exhaust pipe, then the sensor can detect particles effectively, but the sensitivity and dynamics vary depending on the rotation orientation of the sensor
Solution Approach 1:
The protective tube is divided into an inner protective sleeve and an outer protective sleeve with an annular space between them. This segmentation allows independent flow control in different zones, enabling the inner sleeve to create a throttling effect that stabilizes flow regardless of sensor rotation orientation.
Solution Approach 2:
The annular space between the inner and outer protective sleeves acts as an intermediary flow channel. Exhaust gas flows through this annular space before entering the inner protective sleeve, allowing flow homogenization and pressure stabilization that reduces the impact of sensor rotation on detection performance.
2Speed
If the gas inlet of the inner protective sleeve forms the smallest flow cross-section, then the exhaust gas flow is homogenized and accelerated towards the sensor element, but this creates a relative negative pressure inside the inner protective sleeve that requires careful pressure management
Solution Approach 1:
The flow cross-section parameters are specifically designed with the gas inlet of the inner protective sleeve being the smallest cross-section. This parameter configuration creates a throttling effect that accelerates flow velocity while generating controlled negative pressure, optimizing particle deposition on the sensor element.
Solution Approach 2:
The system utilizes pneumatic principles by creating a pressure differential through the throttling effect at the gas inlet. The negative pressure inside the inner protective sleeve is harnessed to draw exhaust gas homogeneously through the sensor element, converting pressure differences into useful flow control.
3Productivity
If the exhaust gas flow velocity towards the sensor element is increased, then particle deposition efficiency is improved, but the flow must be carefully controlled to maintain homogeneity and avoid turbulence
Solution Approach 1:
The annular space between the inner and outer protective sleeves serves as a preliminary flow conditioning zone. Exhaust gas is homogenized and stabilized in this annular space before entering the inner protective sleeve, ensuring that high-velocity flow towards the sensor element remains homogeneous and avoids turbulence that would reduce deposition efficiency.
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 configuration increases the sensitivity and accuracy of the exhaust gas sensor by ensuring consistent exhaust gas flow and enhanced particle deposition, regardless of sensor orientation, leading to improved detection of soot particles and overall sensor reliability.
Implementation Method 1
a sufficient throttling effect at the gas inlet of the inner protective sleeve, which is ensured when the gas inlet of the inner protective sleeve forms the smallest flow cross-section during the flow through the protective tube, leads to a relative negative pressure inside the inner protective sleeve
Implementation Method 2
a sufficient throttling effect at the gas inlet of the inner protective sleeve, which is ensured when the gas inlet of the inner protective sleeve forms the smallest flow cross-section during the flow through the protective tube
Implementation Method 3
the deposition of soot particles contained in the exhaust gas on the sensor element is particularly efficient when the exhaust gas is directed towards the sensor element at the highest possible flow velocity
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
The invention relates to an exhaust gas sensor, in particular a particle sensor, comprising a sleeve-shaped sensor housing (12), a sensor element (14), which is fixed in the sensor housing (12) and which protrudes beyond the sensor housing (12) on the exhaust gas side, and a sleeve-shaped protective tube (20), which is fastened to the sensor housing (12) on the exhaust gas side, the protective tube (20) consisting of an inner protective sleeve (21) and an outer protective sleeve (22), the inner protective sleeve (21) surrounding an exhaust-gas-side end region (141) of the sensor element (14), the outer protective sleeve (22) surrounding the inner protective sleeve (21) at least in some regions such that an annular space (30) is formed between the outer protective sleeve (22) and the inner protective sleeve (21), the outer protective sleeve (22) and the inner protective sleeve (21) each having a gas outlet and a gas inlet, and flow through the protective tube (20) occurs from the gas inlet of the outer protective sleeve (22) into the annular space (30), from there through the gas inlet of the inner protective sleeve (21) into the interior of the inner protective sleeve (21) and from there through the gas outlets of the outer and inner protective sleeves (21, 22). According to the invention, the gas inlet of the inner protective sleeve (21) forms the smallest flow cross-section for the flow through the protective tube (20).