SCR Reductant Dosing Control via Fluid State Detection
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Solution Overview
Problem
Existing exhaust systems face challenges in accurately monitoring and managing the reductant levels in selective catalytic reduction (SCR) devices, which are crucial for reducing NOx emissions, due to variations in reductant state (frozen/thawed) affecting injection rates and efficiency.
Innovation Solution
A control method and system that determines the fluid state of the reductant supply based on temperature, estimates the average consumption rate, and adjusts reductant dosing to prevent cavity formation and optimize NOx reduction, using a control module with state determination and consumption rate estimation sub-modules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If reductant injection is performed without considering fluid state, then injection rate may be maintained, but cavity formation occurs and injection efficiency deteriorates
Solution Approach 1:
The control method changes the injection rate parameter based on the fluid state (frozen/thawed) of the reductant. When frozen reductant is detected, the injection rate is reduced to prevent cavity formation and ensure reliable injection operation, while maintaining adequate dosing when thawed
Solution Approach 2:
The system uses temperature sensor feedback to determine the fluid state of the reductant and adjusts the injection rate accordingly. The control module continuously monitors temperature and modifies injection parameters based on this feedback to maintain optimal injection efficiency and reliability
2Quantity of substance
If reductant dosing is increased to ensure adequate supply, then NOx reduction is optimized, but cavity formation risk increases during frozen states
Solution Approach 1:
The injection rate parameter is dynamically changed based on fluid state. During frozen conditions, the rate is reduced to prevent cavity formation, while during thawed conditions, the rate can be increased to ensure adequate reductant supply for optimized NOx reduction
3Measurement precision
If temperature monitoring is implemented to determine fluid state, then injection control is improved, but system complexity increases
Solution Approach 1:
The system uses the existing temperature sensor in the reductant supply system to determine fluid state, allowing the system to self-diagnose and self-adjust injection parameters without requiring additional complex monitoring equipment or external intervention
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
Effectively monitors and manages reductant levels, preventing reductant injection issues during frozen states and optimizing NOx reduction by adjusting dosing strategies based on fluid state, ensuring efficient operation of SCR devices.
Implementation Method 1
selectively determining a fluid state from a plurality of fluid states based on a temperature of a fluid supply source
Implementation Method 2
The SCR devices make use of ammonia (NH3) or other reductant to reduce the NOx. For example, when the proper amount of NH3 is available at the SCR device under the proper conditions, the NH3 reacts with the NOx in the presence of an SCR catalyst to reduce the NOx emissions
Data Source
AI summary
A control method for an exhaust treatment system is provided. The method includes: selectively determining a fluid state from a plurality of fluid states based on a temperature of a fluid supply source; estimating an average consumption rate based on the fluid state; and evaluating a fluid supply within the fluid supply source based on the average consumption rate.