Reductant Dosing Control for Varying Catalyst Temperatures
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Solution Overview
Problem
Current reductant dosing control systems for internal combustion engines do not adequately account for varying reaction speeds of reductant and NOx at different temperatures, leading to inaccuracies in reductant injection quantities and suboptimal NOx conversion.
Innovation Solution
A method and control system that adjusts reductant dosing based on inlet temperature, using different processes for temperatures below and above a first threshold, with a controller measuring inlet temperature and adjusting dosing accordingly to achieve target NOx conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single reductant dosing process is used for all temperatures, then the control system is simple, but the NOx conversion accuracy deteriorates at varying temperatures
Solution Approach 1:
The patent applies parameter changes by switching between different dosing processes based on temperature parameters. When temperature exceeds a threshold, the system transitions from a first dosing process to a second dosing process, adjusting the reductant dosing amount according to temperature conditions to maintain accurate NOx conversion across varying thermal environments
Solution Approach 2:
The patent implements dynamics by making the dosing process adaptive rather than static. The control system dynamically selects between different dosing strategies based on real-time temperature measurements, allowing the dosing amount and control parameters to change flexibly with operating conditions to optimize NOx conversion at both low and high temperatures
2Reliability
If reductant dosing is increased to ensure adequate conversion at low temperatures, then NOx conversion is improved, but reductant waste increases at high temperatures
Solution Approach 1:
The patent uses parameter changes to adjust reductant dosing based on temperature. At low temperatures, the system applies a dosing strategy that ensures adequate conversion by storing reductant in the catalyst. At high temperatures, it switches to a different dosing process that reduces reductant amount since the reaction proceeds faster, thereby preventing reductant waste while maintaining conversion reliability
Solution Approach 2:
The patent applies partial action by adjusting reductant dosing to match actual conversion needs at different temperatures. Instead of using excessive reductant at all times, the system uses just enough reductant for low-temperature conversion requirements and reduces dosing at high temperatures where less reductant is needed, optimizing both reliability and substance utilization
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 provides a robust closed-loop control that accurately adjusts reductant dosing to achieve target NOx conversions at both low and high temperatures, reducing performance degradation and ensuring appropriate reductant storage in the catalyst.
Implementation Method 1
SCR catalysts, for example, catalyze a reaction of a reductant (e.g., urea, ammonia) with NOx that converts NOx to harmless compounds
Data Source
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AI summary
Systems and methods for controlling a dosing of reductant for an internal combustion engine system (10) including a catalyst (18) are disclosed. The method (300) includes measuring a value indicative of inlet temperature of the catalyst (18). When the inlet temperature is less than or equal to a first threshold, the method includes adjusting the dosing of reductant according to a first process. When the inlet temperature is greater than the first threshold, the method includes adjusting the dosing of reductant according to a second process, the second process being different than the first process.