Urea Pump Compensation Device for Freezing Damage
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Solution Overview
Problem
Existing Adblue systems for exhaust gas aftertreatment in internal combustion engines are prone to damage due to freezing of aqueous urea solutions, which can cause pump failure and system malfunction, especially during idle times in cold temperatures.
Innovation Solution
A magnetic piston actuator with a compensation device that allows pressure-dependent enlargement of the fluid space, incorporating a flexible coupling and compression spring, along with an electromagnetic device for thawing protection, to prevent damage from volume expansion during freezing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pump is used for metered supply of aqueous urea solution, then precise dosing of the reducing agent is achieved, but the system becomes vulnerable to damage from freezing of the solution
Solution Approach 1:
The patent incorporates a compensation device with a compressible element (such as a spring or elastomeric component) that is pre-installed in the pump housing to absorb the expansion pressure before it can cause damage. This cushioning mechanism is designed to activate specifically when the urea solution freezes and expands, allowing the system to withstand freezing conditions without pump damage while maintaining dosing precision during normal operation.
2Manufacturing precision
If the fluid chamber is made rigid to maintain structural integrity, then manufacturing precision is improved, but the chamber cannot accommodate volume expansion during freezing
Solution Approach 1:
The patent introduces a flexible compensating element (such as a compressible spring, elastomeric diaphragm, or flexible membrane) that is integrated into the rigid pump housing structure. This flexible component allows the fluid chamber to expand when the urea solution freezes, accommodating the volume increase without compromising the overall structural integrity of the pump housing or affecting manufacturing precision.
3Use of energy by moving object
If the pump is kept stationary during idle times to reduce energy consumption, then energy efficiency is improved, but the system becomes more vulnerable to freezing damage
Solution Approach 1:
The compensation device with its compressible element is designed to provide passive protection that activates automatically when freezing occurs, regardless of pump operation status. This eliminates the need for energy-consuming preventive measures during idle times, as the mechanical cushioning structure is always ready to absorb expansion pressure from frozen urea solution without requiring power input.
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
The system effectively minimizes the risk of damage from frost effects while ensuring precise metering of the reducing agent, maintaining operational integrity even in freezing conditions by compensating for volume expansion and providing heat protection to prevent freezing during operation.
Implementation Method 1
the coupling device has a compression spring clamped between the respective pump piston and the actuator, which allows the pump piston to move relative to the actuator against the spring force, thereby increasing the fluid volume
Implementation Method 2
an electromagnetic device for thawing protection
Data Source
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AI summary
A system for exhaust gas treatment for internal combustion engines, having a pump (1) for metered supply of a freezable substance, particularly a urea solution, to a supply device (23) introducing said substance into the exhaust gas flow, is characterised in that a compensation device (25) is provided as protection against damage to the system due to volume expansion when the substance freezes, said compensation device compensating for the volume expansion accompanying an increase of the fluid pressure when the substance freezes.