Exhaust Gas Sensor Protection and Cleaning System
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Solution Overview
Problem
Internal combustion engine sensors in exhaust gas conduits accumulate particulate matter such as combustion soot, leading to reduced performance and short useful life due to exposure to harsh environments, including high temperatures and corrosive compounds, with current technologies failing to effectively prevent or remove these deposits.
Innovation Solution
A system and method employing soot deflectors, surface acoustic wave-based ultrasonic cleaning, and particle charging systems to prevent soot accumulation and remove existing deposits from sensors, utilizing ceramic materials and Teflon coatings for durability and non-adhesion properties, along with temperature control for regeneration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensors are mounted directly into the exhaust stream to measure exhaust gas parameters, then measurement capability is improved, but sensor performance deteriorates due to soot accumulation and harsh environmental exposure
Solution Approach 1:
The sensor system is divided into separate functional components: a sensing element housed within a protective structure that includes soot deflectors and cleaning mechanisms. This segmentation allows the sensor to remain in the exhaust stream for measurement while the protective structures handle the harsh environment exposure.
Solution Approach 2:
Soot deflectors and protective housings are introduced as intermediary elements between the exhaust stream and the sensor. These intermediaries capture and redirect soot particles away from the sensing element, allowing the sensor to maintain measurement capability without direct soot accumulation.
2Productivity
If sensors operate in harsh exhaust environments with high temperatures and corrosive compounds, then measurement function is maintained, but sensor useful life shortens due to accumulated particulate matter
Solution Approach 1:
The system implements periodic cleaning cycles using ultrasonic vibrations or heated airflow to remove accumulated soot from the sensor surface. This periodic maintenance action restores sensor performance and extends useful life while maintaining continuous operation capability between cleaning cycles.
Solution Approach 2:
The sensor system includes self-cleaning mechanisms such as ultrasonic transducers or heated elements that automatically remove soot accumulation without requiring manual intervention. The sensor serves itself by incorporating cleaning functions directly into its structure, extending operational life while maintaining continuous measurement capability.
3Measurement precision
If soot accumulates on sensors during engine operation and hardens after engine shutdown, then sensor output becomes constantly non-zero, but cleaning complexity increases due to hardened deposits
Solution Approach 1:
The system performs preliminary cleaning actions during engine operation or immediately upon shutdown before soot hardens and becomes difficult to remove. By cleaning while deposits are still soft, the system maintains measurement accuracy without requiring complex high-power cleaning mechanisms that would be needed for hardened soot.
Solution Approach 2:
The cleaning system utilizes parameter changes in the soot deposits themselves - specifically the transition from soft to hard state - to determine optimal cleaning timing. By monitoring temperature and operational state parameters, the system cleans at the optimal moment when soot is most easily removed, minimizing cleaning complexity while maintaining accuracy.
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 solution effectively prevents soot accumulation and removes existing deposits, enhancing sensor accuracy and extending their useful life by withstanding harsh conditions and minimizing downtime for regeneration.
Implementation Method 1
an interdigital transducer positioned on a side of a surface of the sensor that propagates surface acoustic waves across the surface
Implementation Method 2
a sensor heating element disposed near the sensor to increase temperature in the vicinity of the sensor
Implementation Method 3
utilizing ceramic materials and Teflon coatings for durability and non-adhesion properties
Data Source
AI summary
A system, apparatus, and method are provided for preventing the accumulation of particulate matter such as combustion soot on sensors positioned in exhaust gas conduits of internal combustion engines. In an embodiment, the apparatus includes a device for deflecting soot deposits from sensor surfaces. In an embodiment, the apparatus includes a device employing a surface acoustic wave generator for dislodging soot accumulation or measuring soot accumulations to trigger burn-off events. In an embodiment, an injector injects pressurized bursts of gas toward a sensor surface to dislodge particulate matter. In an embodiment, charged electrodes attract charged particles of soot from the exhaust gas flow to form deposits that are then subject to burn-off events.