Pump Speed Control for Urea Injector Pressure Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing conveying devices for aqueous urea solutions in motor vehicles face durability issues due to increased load on injectors from high injection frequencies and ammonia demand, leading to pressure fluctuations and potential damage.
Innovation Solution
The method involves controlling the pump speed based on injector opening and closing operations and pressure conditions, using a PID controller with adapted I and D components, and maintaining system pressure by continuous pumping, even when the injector is closed, to minimize pressure fluctuations and ensure stable pressure conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the injection frequency is increased to meet higher reducing agent demand, then the exhaust gas treatment effectiveness is improved, but the injector durability deteriorates due to increased load
Solution Approach 1:
The pump speed is dynamically adjusted based on the injector opening/closing operations and pressure conditions, transitioning from a static operating mode to a dynamic one that responds to real-time system needs, thereby reducing injector load while maintaining treatment effectiveness
Solution Approach 2:
The conveying speed parameter of the pump is changed and controlled depending on pressure conditions and injector operations, allowing optimization of the balance between reducing agent delivery and injector protection
2Quantity of substance
If the pump conveying speed is increased to compensate for pressure drops, then the volume flow to injector is improved, but pressure fluctuations increase causing harmful effects
Solution Approach 1:
The control system uses feedback from pressure conditions and injector operations to continuously adjust the pump conveying speed, creating a closed-loop control that maintains stable pressure while ensuring adequate volume flow to the injector
Solution Approach 2:
The pump speed is adjusted in advance based on predicted pressure conditions and injector operations, preventing harmful pressure fluctuations before they occur rather than reacting to them after they occur
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 extends injector durability by reducing pressure fluctuations, maintaining constant system pressure, and improving metering accuracy, preventing damage and ensuring effective exhaust gas treatment.
Implementation Method 1
having a pump (104) for conveying the aqueous urea solution
Implementation Method 2
the injector (106) is arranged on an exhaust gas line (112) and is designed to inject the aqueous urea solution into the exhaust gas line
Implementation Method 3
the conveying speed of the pump (104) is controlled depending on the opening operations and closing operations of the injector (106) and/or the pressure conditions resulting therefrom
Data Source
AI summary
A method for operating a conveying device for an aqueous urea solution in a motor vehicle, having a pump for conveying the aqueous urea solution, wherein the aqueous urea solution is conveyed from a tank along a pressure line to an injector, wherein the injector is arranged on an exhaust gas line and is designed to inject the aqueous urea solution into the exhaust gas line. The conveying speed of the pump is controlled depending on the opening operations and closing operations of the injector and/or the pressure conditions resulting therefrom in the conveying section between the pump and the injector.