Particulate Matter Sensor Regeneration Control
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Solution Overview
Problem
Particulate matter detection systems face challenges in accurately detecting the amount of particulate matter and reliably identifying sensor failures, particularly due to unburned particulate matter remaining after the burning process and incomplete connection of electrodes to the current detection part.
Innovation Solution
A particulate matter detection system with a control circuit that switches between detection and burning modes, using a pair of current detection parts to accurately measure currents and leak currents, ensuring thorough regeneration and failure detection by continuously monitoring and adjusting for unburned particulate matter and electrode connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the burning mode is used to remove accumulated particulate matter from the electrodes, then the sensor is regenerated, but unburned particulate matter may remain on the accumulation part, leading to inaccurate detection in subsequent detection modes
Solution Approach 1:
The control circuit performs a preliminary check by detecting current immediately after switching from burning mode to detection mode. If the current exceeds a threshold indicating unburned particulate matter remains, the control circuit executes another burning cycle before proceeding with normal detection, ensuring complete regeneration
Solution Approach 2:
The system uses feedback from current detection to monitor the regeneration status. The control circuit continuously monitors the current value after burning mode and uses this feedback to determine whether additional burning is needed, creating a closed-loop control system that ensures complete particulate matter removal
2Device complexity
If only one current detection part is connected to one electrode, then the device complexity is reduced, but the ability to detect sensor failures and line disconnections is compromised
Solution Approach 1:
The system divides the current detection function into two separate detection parts, each connected to a different electrode. This segmentation allows independent monitoring of each electrode's connection status and failure modes
Solution Approach 2:
Each current detection part is specifically assigned to monitor its connected electrode's local status. The first current detection part monitors the second electrode, and the second current detection part monitors the first electrode, enabling localized failure detection
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 system achieves accurate detection of particulate matter and reliable sensor failure identification, ensuring precise measurement and timely regeneration, thereby improving the reliability and accuracy of particulate matter detection.
Implementation Method 1
the heater part heats the accumulation part to burn particulate matter accumulated between the pair of electrodes
Implementation Method 2
when a voltage is supplied between the pair of electrodes in the particulate matter detection sensor, particulate matter is collected on the pair of electrodes by electrostatic force
Data Source
AI summary
A PM detection system has a PM sensor, current detector, and control circuit. The circuit switches of a detection mode and a burning mode. In the detection mode, the control circuit prohibits supply of power to a heater and supplies a voltage between electrodes, and instructs the current detector to detect a current flowing between the electrodes. In the burning mode, the control circuit instructs the heater to generate heat energy to burn PM accumulated on an accumulation part. The control circuit judges PM has remained on the accumulation part when the detected current exceeds a threshold value, and performs the burning mode again. The system further has a pair of current detectors. Each current detector detects a leak current flowing from the heater to the electrodes through an insulation member when the heater generates heat energy. The circuit detects a sensor failure based on the detected leak current.