Exhaust Aftertreatment Filter Diagnostics Using Pressure and Temperature
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Solution Overview
Problem
Existing diagnostic methods for exhaust gas aftertreatment devices, such as particulate filters, face inaccuracies due to changes in output caused by large particle adhesion and the need for additional capacitors, making precise malfunction detection challenging.
Innovation Solution
A diagnostic device utilizing temperature, differential pressure, and intake air pressure sensors to determine malfunctions in exhaust gas aftertreatment devices by calculating an index based on the ratios of these parameters, avoiding significant output changes and enabling accurate detection before damage occurs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a PM sensor is used to detect particulate matter deposition, then the deposition amount can be measured, but the output changes significantly due to adhesion of large particle size PM
Solution Approach 1:
The patent replaces the PM sensor (electrical resistance-based mechanical/electrical system) with a differential pressure sensor system that measures pressure differences across the filter. This substitution eliminates the adhesion problem affecting PM sensors while maintaining the ability to detect deposition amounts through pressure differential measurements.
Solution Approach 2:
The patent changes the measurement parameter from electrical resistance (PM sensor) to pressure differential (differential pressure sensor). This parameter change allows accurate detection of particulate matter deposition without the output instability caused by large particle adhesion to electrodes.
2Measurement precision
If a capacitor is added to detect electrostatic capacitance for DPF malfunction diagnosis, then the diagnostic capability is improved, but the device complexity increases
Solution Approach 1:
The patent extracts and eliminates the capacitor component from the diagnostic system. Instead of adding a capacitor to measure electrostatic capacitance, the invention uses only the differential pressure sensor to detect DPF malfunction, thereby reducing device complexity while maintaining diagnostic capability.
3Duration of action of stationary object
If the filter operates until damage by melting occurs, then the service life is maximized, but the reliability is compromised
Solution Approach 1:
The patent implements preliminary detection of filter degradation through differential pressure measurement. By detecting increased deposition amounts before the filter reaches its melting point, the system enables preventive maintenance actions, extending the safe service life while maintaining reliability through early warning of potential failures.
Solution Approach 2:
The patent establishes a feedback mechanism where differential pressure sensor data is continuously monitored to assess filter condition. This feedback loop allows the system to detect degradation trends and alert operators before catastrophic failure occurs, balancing service life extension with reliability maintenance.
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 high-accuracy detection of malfunctions in exhaust gas aftertreatment devices by using temperature, differential pressure, and intake air pressure sensors, preventing damage by melting and ensuring device safety.
Implementation Method 1
a temperature detection device that detects a filter inlet-side temperature and a filter outlet-side temperature
Implementation Method 2
a differential pressure detection device that detects a differential pressure between a filter inlet-side pressure and a filter outlet-side pressure
Implementation Method 3
an intake air pressure detection device that detects an intake air pressure of the engine
Data Source
AI summary
A diagnostic device for an exhaust gas aftertreatment device includes a temperature detection device that detects a filter inlet-side temperature and a filter outlet-side temperature, a differential pressure detection device that detects a differential pressure between a filter inlet-side pressure and a filter outlet-side pressure, an intake air pressure detection device that detects an intake air pressure of an engine, and a controller that determines a malfunction in an exhaust gas aftertreatment device based on values detected by the temperature detection device, the differential pressure detection device, and the intake air pressure detection device.