Suction-Side Filter Delivery Module for Urea Dosing
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Solution Overview
Problem
Existing dosing systems for reducing agents like aqueous urea solutions in motor vehicles face issues with particle-induced wear and leakage due to reverse flow modes, leading to insufficient pressure build-up and throughflow rates, especially at low temperatures where freezing can cause ice pressure damage.
Innovation Solution
A delivery module with a filter integrated on the suction side of the pump, a compensation volume for deaeration and ice pressure protection, and a 4/2-way valve for mode switching without pump direction reversal, along with a bypass line and check valve to prevent particle detachment and ensure proper flow direction, reduces wear and ensures sufficient pressure and flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a filter is arranged in the delivery line to protect the dosing valve, then particle protection is improved, but particles detached during sucking-back mode cause increased wear at valves and constrictions
Solution Approach 1:
The filter is extracted from its traditional position in the delivery line and relocated to the suction line upstream of the pump. This separation allows the filter to remain in place during dosing mode while preventing particle detachment during sucking-back mode, as the filter is now isolated from the flow reversal that occurs in the delivery line.
Solution Approach 2:
Instead of placing the filter downstream where it protects the dosing valve but causes wear during reverse flow, the filter is placed upstream of the pump. This inversion of the filter's position relative to the pump and delivery line eliminates the problem of particle detachment during sucking-back mode while maintaining filtration effectiveness during normal dosing operation.
2Strength
If the reducing agent is delivered back into the storage tank in sucking-back mode, then ice pressure damage is prevented, but particles previously separated at the filter are detached and pass into function components
Solution Approach 1:
The filter is extracted from the delivery line and positioned in the suction line upstream of the pump. This spatial separation ensures that during sucking-back mode, when flow reverses in the delivery line, particles cannot be detached from the filter and transported to downstream valves and constrictions, as the filter remains upstream of the reversal zone.
Solution Approach 2:
The pump acts as an intermediary element between the filter and the delivery line. By positioning the filter upstream of the pump, the pump serves as a barrier that prevents particles detached in the suction line from reaching the delivery line and subsequent function components during sucking-back mode.
3Reliability
If multiple filters are arranged in the system, then particle protection is improved, but device complexity and installation space increase
Solution Approach 1:
The single filter arranged upstream of the pump performs multiple functions: it filters particles from the reducing agent before it enters the pump during dosing mode, and it prevents particle detachment and transport to downstream components during sucking-back mode. This multi-functional placement eliminates the need for separate filters in the delivery line and return line, reducing overall system complexity.
Solution Approach 2:
The filter function is merged into a single component positioned upstream of the pump, rather than having separate filters distributed throughout the delivery line and return line. This consolidation reduces the total number of filters needed while maintaining comprehensive particle protection during both dosing and sucking-back modes.
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 solution enhances the reliability of the dosing system by protecting critical components from particle damage, maintaining sufficient pressure and flow rates, and improving deaeration, thus preventing leakage and ensuring effective operation over time.
Implementation Method 1
a filter which protects the pump and all following components against particles
Implementation Method 2
a compensation volume for deaeration and ice pressure protection
Implementation Method 3
a pump (2), which is connected to the storage tank (4) and the dosing module (6)
Implementation Method 4
along with a bypass line and check valve to prevent particle detachment and ensure proper flow direction
Data Source
AI summary
The invention relates to a delivery module (1) for a metering system for metering a reducing agent, in particular an aqueous urea solution, into an exhaust gas section of a motor vehicle, comprising a pump (2) which is connected or can be connected to a reducing agent storage tank (4) on the suction side via a suction line (3) and to a metering module (6) on the pressure side via a delivery line (5), wherein a return line (7) which leads back into the storage tank (4) branches off from the delivery line (5). According to the invention, a filter (8) is integrated into the delivery module (1) on the suction side. The invention additionally relates to a metering system comprising such a delivery module (1).