SCR Dosing Unit Intermittent Cooling Control
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Solution Overview
Problem
Current SCR systems face issues with overheating of the dosing unit after vehicle shutdown, leading to energy inefficiency, noise disturbance, and potential damage to electrical components due to continuous cooling by the pump after the engine is turned off.
Innovation Solution
Implementing a method where the feed device for the SCR system operates intermittently at reduced power after the exhaust flow cessation, using a predetermined interval configuration to maintain cooling while minimizing energy consumption and noise, and preventing overheating by deactivating and reactivating the pump as needed to maintain a desirable temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the pump continues to operate continuously after vehicle shutdown to cool the dosing unit, then the dosing unit temperature is maintained below critical levels, but energy consumption increases and battery charge depletes
Solution Approach 1:
The pump operates intermittently with predetermined interval configurations rather than continuously. The control unit activates the pump for specific durations after vehicle shutdown based on stored cooling requirements, then deactivates it, creating periodic cooling cycles that reduce energy consumption while maintaining adequate cooling of the dosing unit.
Solution Approach 2:
The system performs cooling action in advance during vehicle operation and immediately after shutdown before thermal damage can occur. The control unit monitors temperature and activates the pump preemptively to remove excess heat from the dosing unit before it reaches critical levels, preventing damage rather than reacting to it.
2Temperature
If the pump operates continuously after vehicle shutdown to cool the dosing unit, then overheating is prevented, but noise disturbance increases
Solution Approach 1:
The pump operates intermittently with predetermined interval configurations rather than continuously. The control unit activates the pump for specific durations after vehicle shutdown based on stored cooling requirements, then deactivates it, creating periodic cooling cycles that reduce energy consumption while maintaining adequate cooling of the dosing unit.
3Temperature
If the dosing unit is cooled continuously during vehicle operation, then the dosing unit temperature remains controlled, but reductant crystallization risk increases at high temperatures
Solution Approach 1:
The control unit monitors the temperature of the dosing unit and adjusts pump operation accordingly. When temperature reaches thresholds that could cause reductant crystallization, the control unit activates or reactivates the pump to remove excess heat, creating a feedback loop that prevents crystallization while minimizing unnecessary cooling 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 approach reduces energy consumption by 10-50% compared to traditional methods, minimizes noise, and prevents overheating and crystallization of the reductant, thereby extending the lifespan of the dosing unit's electrical components.
Implementation Method 1
cooling the dosing unit by means of reductant which, during cooling, flows from the container via the pump and the dosing unit and back to the container
Implementation Method 2
After operation of the vehicle a large amount of thermal energy caused by its operation is stored in primarily the exhaust system. This thermal energy may be led to the dosing unit from, for example, a silencer and the SCR catalyst
Data Source
Figure 1~2
Figure 3a~3b
Figure 4a~4b
AI summary
The invention relates to a method for cooling a dosing unit (250) pertaining to SCR systems for exhaust cleaning, comprising the steps, after cessation of exhaust flow, of cooling a reducing agent dosing unit (250) by means of reducing agent supplied to it, and of intermittently running a feed device (230) to supply said coolant reducing agent, and running said feed device (230) at reduced power compared with ordinary operation. The invention relates also to a computer programme product containing programme code (P) for a computer (200; 210) for implementing a method according to the invention. The invention relates also to an SCR system and a motor vehicle (100; 110) which is equipped with the SCR system.