PM Sensor Mounted Condition Diagnosis via Engine-Dependent Threshold
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Solution Overview
Problem
Existing particulate matter detecting apparatuses for internal combustion engines face challenges in reliably diagnosing the mounted condition of particulate matter sensors, often requiring temperature measurements and profiles that can lead to errors and prolonged diagnosis times.
Innovation Solution
A particulate matter detecting apparatus with a sensor body, a sensor temperature determining unit, and a mounted condition diagnosis unit that sets a diagnosis threshold based on the engine's operating conditions, allowing for accurate diagnosis without direct temperature measurement of exhaust gas, by comparing the sensor temperature with a threshold value derived from the engine's operating parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If temperature profile comparison method is used to diagnose PM sensor mounted condition, then diagnosis can be performed, but diagnosis time increases and errors may occur
Solution Approach 1:
The patent extracts only the essential diagnostic parameter (sensor temperature) from the complex temperature profile comparison method. Instead of comparing entire temperature profiles over time, the invention isolates and monitors only the current sensor temperature against a predetermined threshold, eliminating the time-consuming profile analysis while maintaining diagnostic capability.
Solution Approach 2:
The patent performs preliminary action by pre-establishing the diagnosis threshold temperature value based on engine operating conditions and sensor characteristics. This predetermined threshold is stored in advance, allowing immediate comparison with current sensor temperature without requiring real-time profile analysis, thus reducing diagnosis time while maintaining reliability.
2Reliability
If temperature measurement and profile comparison is performed, then mounted condition can be diagnosed, but system complexity increases
Solution Approach 1:
The invention extracts only the critical element (sensor temperature value) from the complex temperature profile comparison system. By focusing solely on comparing current sensor temperature against a predetermined threshold, the system eliminates the complexity of continuous profile measurement, storage, and comparison while maintaining diagnostic accuracy.
Solution Approach 2:
The patent changes the diagnostic parameter from a complex temperature profile (multiple data points over time) to a single temperature threshold value. This parameter simplification reduces system complexity by eliminating the need for continuous profile measurement and comparison infrastructure, while the threshold is dynamically adjusted based on engine operating conditions to maintain accuracy.
3Measurement precision
If direct temperature measurement of exhaust gas is performed, then accurate diagnosis can be achieved, but additional sensors and measurement means are required
Solution Approach 1:
The patent applies self-service by utilizing the PM sensor's own temperature measurement capability for mounted condition diagnosis. The sensor already contains temperature measurement functionality for its operation, and this existing capability is repurposed for diagnostic purposes. No additional temperature sensors or measurement infrastructure are required, as the sensor serves both its detection function and self-diagnosis function.
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 approach enables rapid and reliable diagnosis of the mounted condition of the sensor, reducing errors and improving the overall reliability of the exhaust emission control system by eliminating the need for temperature profile comparisons.
Implementation Method 1
a sensor device which is retained in a housing configured to be secured to an exhaust pipe of an internal combustion engine and detects particulate matter contained in exhaust gas
Implementation Method 2
a sensor temperature determining unit which works to determine a temperature of the sensor device
Data Source
AI summary
A particulate matter detecting apparatus (S) comprises a sensor body (S1) which has a sensor device (1) which is retained in a housing (H) secured to an exhaust pipe (101) of an internal combustion engine (ENG) and detects particulate matter contained in exhaust gas, a sensor temperature determining unit (2) which works to determine a temperature of the sensor device, and a mounted condition diagnosis unit (3) which diagnoses a mounted condition where the sensor body is mounted in the exhaust pipe. The mounted condition diagnosis unit includes a diagnosis threshold setting unit (31) and a mount error determining unit (32). The diagnosis threshold setting unit determines a diagnosis threshold (Tth), as used in a diagnosis of the mounted condition, as a function of an operating condition of the internal combustion engine to have a temperature value lower than a temperature of the sensor device when the sensor body is normally mounted in the exhaust pipe. When a sensor temperature (T), as determined by the sensor temperature determining unit, is lower than the diagnosis threshold, the mount error determining unit determines that an error in the mounted condition is occurring.