Pump-Nozzle Unit for Reducing Agent Injection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing injection devices for reducing nitrogen oxides in motor vehicle exhaust gases face challenges in precise dosing due to high temperatures and long intake lines, leading to throttling losses and boiling of the reducing agent, which complicates accurate delivery without additional pump means.
Innovation Solution
A pump-nozzle unit with a non-return valve acting as a pressure accumulator and armature bores for rapid fluid exchange, combined with a check valve and an umbrella valve, ensures accurate and reliable dosing of the reducing agent near the exhaust gas tract without additional pumps, using a piston and magnetic coil for fluid management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a long intake line is used to supply reducing agent from storage tank to exhaust pipe, then the pump can be positioned away from exhaust gas tract, but throttling losses increase and dosing precision deteriorates
Solution Approach 1:
The patent combines the pump and nozzle into a single integrated pump-nozzle unit positioned at the exhaust pipe. This merging eliminates the need for a long intake line and intermediate throttling elements, thereby reducing throttling losses while maintaining precise dosing capability through the integrated design.
2Loss of energy
If pump-nozzle unit is positioned near exhaust gas tract, then throttling losses are reduced, but high temperatures cause reducing agent to boil and dosing precision deteriorates
Solution Approach 1:
The patent implements preliminary cooling of the reducing agent before it enters the high-temperature zone at the exhaust pipe. The intake line is designed with cooling measures to maintain the reducing agent temperature below its boiling point, ensuring reliable dosing precision even when the pump-nozzle unit is positioned near the exhaust gas tract.
3Measurement precision
If additional pre-supply pump is added to pressurize reducing agent, then dosing precision is improved, but device complexity increases
Solution Approach 1:
The patent merges the dosing pump and injection nozzle into a single integrated unit, eliminating the need for separate pre-supply pumps. The pump-nozzle unit achieves precise dosing through its internal piston mechanism and nozzle design, thereby maintaining dosing precision while reducing device complexity.
4Device complexity
If pump-nozzle unit operates without pre-supply pressurization, then device complexity is reduced, but boiling of reducing agent occurs and dosing reliability deteriorates
Solution Approach 1:
The patent implements preliminary cooling measures in the intake line to prevent boiling of the reducing agent before it reaches the pump-nozzle unit. This preliminary action ensures that the reducing agent remains in liquid form and can be reliably dosed, even without additional pre-supply pressurization devices.
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 configuration enables precise and reliable dosing of the reducing agent, minimizing throttling losses and preventing boiling, ensuring effective reduction of nitrogen oxides in the exhaust gas while maintaining efficient operation.
Implementation Method 1
The housing 4 houses a magnetic coil 3 for the electrically controlled movement of a piston 2 connected to an armature 1
Implementation Method 2
a check valve 7, in particular a non-return valve with an elastic closing element 28, which opens with very small pressure differences
Implementation Method 3
an atomizing element 14 which discharges pressurized fluid originating from the expansion chamber 20 in the form of an injection jet 18 into the exhaust pipe
Data Source
Figure 1
Figure 2
AI summary
The invention relates to an injecting device (25) for injecting a reductant into an exhaust-gas system of an internal combustion engine, comprising a compression chamber (16), the volume of which can be varied by moving a piston (2), which has a compression-chamber-side region (21) facing the compression chamber (16) and an armature-side region (22) facing away from the compression chamber, and an inlet valve (13, 19), which has at least one open position, in which the inlet valve creates a fluid connection between the compression chamber (16) and an external fluid source that can be connected to a fluid inlet (17) of the injection device, and at least one closed position, in which the inlet valve closes the fluid connection between the compression chamber (16) and the external fluid source, characterized in that a check valve (7) is arranged between the fluid inlet (17) and the armature-side region (22).