Exhaust Nozzle Clogging Detection Logic
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Solution Overview
Problem
Existing exhaust gas purification systems for engines erroneously detect clogging in injection nozzles due to temperature-induced melting of deposited reducing agents, leading to false positives in pressure-based detection methods.
Innovation Solution
A clogging detection unit that combines pressure and temperature sensors with a logic circuit to determine clogging by performing a logical AND operation on outputs exceeding predetermined threshold values, ensuring accurate detection of major clogging while excluding minor, temperature-induced issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure-based detection method is used to detect injection nozzle clogging, then clogging detection capability is improved, but erroneous detection occurs due to temperature-induced melting of deposited reducing agents
Solution Approach 1:
The patent combines pressure-based detection and temperature-based detection into a unified clogging detection system. The determination unit integrates both detection signals to make a final clogging determination, merging the advantages of both methods while compensating for their individual limitations.
Solution Approach 2:
The temperature detection acts as an intermediary that provides context information about the injection nozzle state. By introducing temperature as a mediating parameter, the system can distinguish between pressure changes caused by actual clogging versus those caused by temperature-induced melting of deposits.
2Device complexity
If only pressure detection is used, then device complexity is reduced, but detection accuracy deteriorates due to false positives from temperature effects
Solution Approach 1:
The patent merges pressure detection and temperature detection into a single integrated determination system. This combination improves measurement precision by using multiple parameters to make a more accurate clogging determination, while the integration is designed to minimize additional device complexity.
Solution Approach 2:
The determination unit is designed to handle multiple detection functions - both pressure-based clogging detection and temperature-based state assessment - within a single component. This multi-functionality approach improves accuracy without proportionally increasing overall system complexity.
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
Prevents erroneous detection of clogging by accurately distinguishing between significant and minor blockages, ensuring reliable reducing agent supply to the exhaust gas purification system.
Implementation Method 1
detecting the pressure change in the high-pressure air
Implementation Method 2
detecting a temperature of the injection nozzle
Implementation Method 3
performing a logical AND operation on outputs exceeding predetermined threshold values
Data Source
AI summary
An exhaust gas purification apparatus of an engine, capable of preventing erroneous detection of an injection nozzle clogging, and having a reducing catalytic converter disposed in an exhaust system, for reducing and purifying nitrogen oxide in the exhaust gas using urea water; a urea water tank storing the urea water; a urea water supply unit sucking up the urea water from the urea water tank and mixes it with high-pressure air for delivery; and an injection nozzle injecting the urea water mixed with the high-pressure air, into an exhaust gas moving upstream side of the reducing catalytic converter in an exhaust gas passage, and further having a clogging detection unit capable of detecting clogging of the injection nozzle based on each detection output of a pressure of the air introduced into the urea water supply unit, and a temperature of the injection nozzle.