SCR Thawing Control via Pump Pressure Feedback
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Solution Overview
Problem
Conventional SCR thawing control systems fail to detect thawing failures accurately, leading to potential pump malfunctions and shortened pump lifetime due to insufficient thawing detection in the urea water supply system, especially in cold weather conditions.
Innovation Solution
The proposed SCR thawing control method includes a thawing control unit that monitors pressure changes within the supply module and distinguishes between thawing failure and malfunction by detecting ambient temperature and pressure anomalies, preventing SM pump malfunctions by stopping operation when predetermined pressure values are not maintained.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the tank temperature or SM temperature is used to determine thawing completion, then the control system can operate the SM pump, but urea water may remain frozen in portions spaced apart from temperature sensors causing pump malfunction
Solution Approach 1:
The system uses the SM pump's own operation characteristics (current, pressure, speed) to detect thawing completion and frozen conditions, eliminating the need for additional temperature sensors in the urea pipe. The pump serves both its primary function and as a sensor for detecting system state.
Solution Approach 2:
The patent replaces temperature-based detection (thermal field) with electrical/current-based detection (electrical field) by monitoring pump current and pressure to determine thawing status, avoiding the need for physical temperature sensors in hard-to-reach locations.
2Productivity
If the SM pump operates at maximum power during insufficient thawing, then the pump can attempt to move urea water, but ice grain or unthawable urea water flows into the pump causing load and potential malfunction
Solution Approach 1:
The system continuously monitors pump current, pressure, and rotation speed, and uses this feedback to detect frozen conditions. When freezing is detected through abnormal current or pressure patterns, the control unit stops the pump to prevent damage, creating a closed-loop control system that adapts to real-time conditions.
Solution Approach 2:
The system performs preliminary detection of frozen conditions by monitoring pump operation parameters before actual damage occurs. By detecting abnormal current or pressure patterns early, the system can stop the pump in advance to prevent ice grains from causing malfunction.
3Measurement precision
If the pressure is not maintained at predetermined value during pump operation, then the system can detect potential frozen conditions, but the pump may continue operating causing malfunction
Solution Approach 1:
The system uses pressure feedback from the urea water supply line to detect frozen conditions. When pressure deviates from the predetermined range, the control unit interprets this as a frozen condition signal and stops the pump to prevent damage, ensuring both accurate detection and safe operation.
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 method effectively differentiates between thawing failure and malfunction, preventing SM pump malfunctions and ensuring secure thawing of urea water, thereby extending pump lifetime and maintaining system reliability.
Implementation Method 1
a supply module 106 for supplying the urea water stored in the urea tank 105 to the dosing valve 104
Implementation Method 2
a thawing control unit 128 that detects a pressure inside the supply module 106 when the SM pump 112 is operated
Implementation Method 3
an SCR thawing control system that supplies engine cooling water to a urea water supply system in cold weather and performs a thawing control for thawing frozen urea water
Data Source
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AI summary
Provided is an SCR thawing control system that can distinguish between a thawing failure and a malfunction and can prevent a malfunction of an SM pump. When urea water is frozen in any one of a urea tank 105 for storing urea water, liquid feed, pump and recovery lines 116, 117, 118 between the urea tank 105 and a dosing valve 104 for injecting urea water on an upstream side of an SCR device 103, and a supply module 106 connected to the liquid feed, pump and recovery lines 116, 117, 118, an SCR thawing control system 127 thaws the frozen urea water by engine cooling water and operates an SM pump 112 of the supply module 106 after the thawing to inject the thawed urea water from the dosing valve 104. The thawing control system 127 includes a thawing control unit 128 that detects a pressure inside the supply module 106 when the SM pump 112 is operated, and stops the operation of the SM pump 112 and continues thawing of the urea water when the pressure is less than a predetermined value.