Reciprocating Pump Back-Suction Noise Reduction
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Solution Overview
Problem
Current reagent metering systems for internal combustion engines, particularly those using reciprocating pumps, generate excessive noise during back-suction operations due to the absence of reagent, leading to increased wear and manufacturing costs, and are prone to damage from freezing urea-water solutions.
Innovation Solution
A method that reduces the activation power of the reciprocating pump by determining the flight time of the piston and comparing it to a threshold value, thereby lowering the noise generation during back-suction by reducing the magnetic force and adjusting the pulse-width-modulated signal to maintain efficient reagent suction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a reciprocating pump is used for back-suction operations, then reagent can be effectively suctioned back into the tank, but excessive noise is generated due to the absence of reagent during back-suction
Solution Approach 1:
The pump activation power is dynamically adjusted based on the detected flight time of the reciprocating piston. When flight time indicates low reagent levels, the activation power is reduced to minimize noise from armature impacts, while still maintaining sufficient pumping action for effective back-suction
Solution Approach 2:
The activation power parameter of the reciprocating pump is changed based on the flight time measurement. By comparing flight time to threshold values, the system adjusts the pump's activation power to optimize the balance between back-suction efficiency and noise reduction
2Productivity
If the reciprocating pump operates with high activation power, then back-suction is more effective, but wear on the pump components increases
Solution Approach 1:
The activation power is dynamically adapted based on real-time flight time detection. During back-suction operations, the pump operates at reduced power levels when flight time indicates low reagent conditions, reducing mechanical wear on the armature and piston while maintaining adequate back-suction performance
Solution Approach 2:
The system proactively reduces activation power before severe wear can occur by detecting flight time patterns that indicate low reagent levels. This preventive approach cushions against excessive mechanical stress and extends pump component lifespan
3Ease of operation
If the urea-water solution is left in the reagent metering system after shutdown, then the system remains ready for quick restart, but damage occurs due to freezing expansion
Solution Approach 1:
The system performs back-suction of the urea-water solution before shutdown or in cold conditions as a preliminary protective action. This prevents freezing expansion damage by removing the reagent from vulnerable components like lines and the metering valve before the system stops operating
Solution Approach 2:
The system converts the potential harm of leftover reagent freezing into a benefit by implementing automatic back-suction. The same reciprocating pump that performs metering also sucks back the reagent, turning a protective function into an integrated operation that eliminates freezing risks
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
Significantly reduces noise during back-suction operations and extends the lifespan of the reciprocating pump by minimizing wear, while preventing damage from freezing reagents through controlled reagent back-suction.
Implementation Method 1
a solenoid actuator, specifically a reciprocating pump, in which an armature surrounded by a solenoid carries out a reciprocating movement
Implementation Method 2
The urea-water solution which is customarily used and is defined in DIN standards has the property of freezing at approximately −11° C. The volumetric expansion of the urea-water solution that is associated with the freezing
Data Source
AI summary
A method for operating a reagent metering system which meters a reagent into an exhaust duct of an internal combustion engine upstream of an SCR catalytic converter, in which, after the metering operation is ended, at least part of the reagent metering system is emptied by back-suction by means of a reciprocating pump. The procedure according to the invention is distinguished in that during the back-suction, a stop determination determines the flight time of a reciprocating piston of the reciprocating pump from a starting time as far as the stop time, in that a comparator compares the flight time determined with a flight time threshold value, and in that the activation power of the reciprocating pump is reduced if the flight time determined is less than the flight time threshold value.