Urea Concentration Identification Device Using Single-Pulse Heating
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Solution Overview
Problem
Existing methods for identifying urea concentration in urea solutions used for exhaust purification in internal-combustion engines are inefficient, as they require significant time and lack sensitivity, making it difficult to maintain the desired concentration for effective NOx decomposition.
Innovation Solution
A urea concentration identification device with an indirectly-heated concentration detector and liquid temperature detector, using a single-pulse voltage to generate heat and calculate the difference in voltage values between initial and peak temperatures to accurately and promptly determine urea concentration, with a microcomputer-based identification operation unit and calibration curves for precise measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If periodic multi-pulse current is applied to the heating element for fluid identification, then the fluid identification can be carried out, but the identification time becomes considerable and instant identification is difficult
Solution Approach 1:
The patent applies periodic action by using multi-pulse current applied to the heating element at predetermined time intervals. This periodic heating pattern enables the temperature sensing element to detect temperature changes caused by heat transfer from the heating element to the fluid, allowing for accurate fluid identification while managing the time required for measurement through controlled pulsing cycles.
2Measurement precision
If periodic multi-pulse current is applied to the heating element, then fluid identification can be carried out, but it is difficult to identify urea concentration correctly and promptly
Solution Approach 1:
The patent applies parameter changes by measuring the temperature of the temperature sensing element at specific time points (initial temperature before pulsing and peak temperature during/after pulsing) and using the temperature difference to calculate urea concentration. This approach enables prompt and accurate urea concentration identification by transforming the periodic heating pattern into a measurable parameter that correlates with concentration levels.
3Measurement precision
If NOx sensors are arranged at upstream and downstream sides of catalyst device to measure NOx concentration difference, then the effect of NOx decomposition can be measured, but the method cannot identify urea concentration before spraying or at the beginning of spraying
Solution Approach 1:
The patent introduces an intermediary approach by using a temperature sensing element as a mediator to indirectly measure urea concentration. Instead of directly measuring NOx or urea, the system uses temperature changes in the sensing element caused by heat transfer from the heating element to infer urea concentration levels, enabling measurement before and during the spraying process.
4Adaptability or versatility
If conventional fluid identification method with periodic heating is used, then fluid identification can be achieved, but the method requires considerable time and lacks sensitivity for urea concentration
Solution Approach 1:
The patent applies mechanics substitution by replacing the conventional periodic heating approach with a single-pulse voltage application to the heating element. This substitution maintains the ability to identify fluids and measure urea concentration while improving sensitivity and reducing measurement time through the more efficient single-pulse heating pattern that creates sufficient temperature differential for accurate measurement.
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 stable and precise urea concentration identification within the tank, unaffected by external conditions, allowing for prompt and correct urea concentration measurement, enhancing the efficiency of NOx decomposition in exhaust purification systems.
Implementation Method 1
a single-pulse voltage is applied to the heating element of the indirectly-heated concentration detector to make the heating element generate heat
Implementation Method 2
the indirectly-heated concentration detector has a heat transfer member for concentration detector for exchanging heat with the urea solution
Implementation Method 3
exerting a thermal influence on heat transfer from the heating element to the temperature sensing element by means of fluid to be identified
Data Source
AI summary
A urea concentration identification device comprising a concentration identification sensor unit (2) and a support unit (4) attached at the bottom end thereof with this sensor unit and provided at the top end thereof with a mounting unit (4a) to a urea solution tank opening. The concentration identification sensor unit (2) has an indirectly-heated concentration detector and liquid temperature detector provided with metal fins (21c),(22c), respectively, for heat-exchanging with urea solution. The concentration identification sensor unit (2) is provided with a cover member (2d) that forms an opposite-ends-opened urea solution induction passage so as to surround the metal fins (21c), (22c). A single-pulse voltage is applied to the heating element of the indirectly-heated concentration detector to heat it, and a urea concentration is identified at an identification operation unit based on an output from a concentration detection circuit including the temperature sensing element of the indirectly-heated concentration detector and the liquid temperature detector.