Oxygen Sensor Exhaust Gas Temperature Detection
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Solution Overview
Problem
Existing methods for diagnosing the presence and operation of exhaust gas depollution devices in motor vehicles are costly due to the need for multiple temperature sensors and cannot detect the operating phases of particulate filters effectively.
Innovation Solution
A method using upstream and downstream oxygen sensors to determine the temperature of exhaust gases, detecting the presence of the depollution device by measuring the time interval between temperature changes and identifying regeneration phases through exothermic phenomena, reducing the number of necessary elements and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature sensors are installed upstream and downstream of the particulate filter to detect its presence, then the detection accuracy is improved, but the device complexity and manufacturing costs increase
Solution Approach 1:
The oxygen sensors perform multiple functions: they measure oxygen concentration in exhaust gases and simultaneously detect temperature variations to identify the particulate filter's presence and regeneration phases. This multi-functionality eliminates the need for dedicated temperature sensors while maintaining detection accuracy.
Solution Approach 2:
The patent uses oxygen sensors as intermediary devices that indirectly measure temperature through their electrical characteristics (Nernst resistance) rather than directly measuring temperature with dedicated sensors. This intermediary approach allows temperature detection using existing oxygen sensing infrastructure.
2Reliability
If multiple temperature sensors are installed to monitor exhaust gas temperature for depollution device diagnosis, then the diagnostic capability is improved, but the manufacturing costs increase
Solution Approach 1:
Existing oxygen sensors are utilized for dual purposes: oxygen concentration measurement and temperature detection through Nernst resistance measurement. This eliminates the need for additional temperature sensing hardware, reducing manufacturing costs while maintaining diagnostic capability.
Solution Approach 2:
The oxygen sensors serve themselves by using their own electrical characteristics (Nernst resistance) to detect temperature. This self-service approach eliminates the need for separate temperature measurement systems, reducing overall system complexity and cost.
3Measurement precision
If temperature sensors are used to detect particulate filter presence, then the detection accuracy is improved, but the ability to detect regeneration phases is limited
Solution Approach 1:
The system continuously monitors the Nernst resistance of oxygen sensors and uses this feedback to detect temperature variations that indicate different operational phases (normal operation, passive regeneration, active regeneration). This feedback mechanism enables comprehensive phase detection using existing oxygen sensor infrastructure.
Solution Approach 2:
The oxygen sensors detect multiple operational phases (filter presence, passive regeneration, active regeneration) through temperature variations, making the detection system versatile enough to identify all significant states of the depollution device without requiring different sensor types for each phase.
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
Enables the detection of the depollution device's presence and operation, including regeneration phases, while minimizing hardware requirements and costs, effectively ensuring compliance with emission standards.
Implementation Method 1
Each step for determining the temperature includes a sub-step for measuring the value of the Nernst resistance of the oxygen sensor during said current peak
Implementation Method 2
a step of determining the regeneration of the depollution device if the determined temperatures result in the detection of an exothermic phenomenon between said upstream oxygen sensor and said downstream sensor
Data Source
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AI summary
The invention relates to a diagnostic method for a depollution device (21) of a motor vehicle (1) comprising a gasoline-operated internal combustion engine (10) and a device (21) for depolluting the exhaust gases of said internal combustion engine, said exhaust gases being designed to pass through said depollution device (21) from upstream to downstream, said vehicle (1) comprising an upstream oxygen probe (22) located upstream of the depollution device (21) and a downstream oxygen probe (23) located downstream of the depollution device (21), said method comprising a step of determining the temperature of the exhaust gases by means of each of the oxygen probes (22, 23), a step of detecting the presence of the depollution device (21) between the oxygen probes (22, 23) and a step of determining the regeneration of the depollution device (21) if the determined temperatures detect an exothermic phenomenon between said upstream oxygen probe (22) and said downstream probe (23).