Dosing Module Urea Crystal Melting via Solenoid Heating
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Solution Overview
Problem
Existing dosing modules for emission abatement systems face challenges in melting urea crystals due to the presence of a cooling jacket, which hinders the effective supply of urea to the exhaust passage, especially at lower temperatures, leading to blockages and reduced efficiency in NOx reduction.
Innovation Solution
A method is introduced where the dosing module is heated using an increased electrical current, specifically at least 400 milliamps, to raise the temperature to 100°C, ensuring the melting of urea crystals even with a cooling jacket, by utilizing a solenoid coil and armature mechanism to maintain the dosing module in an unblocked condition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the dosing module is equipped with a cooling jacket to prevent overheating, then the reliability of the dosing module is improved, but the ability to heat the dosing module to melt urea crystals is worsened
Solution Approach 1:
The patent changes the electrical parameters (current and voltage) supplied to the heating element. By increasing the electrical current to at least 400mA and adjusting the voltage, the system can generate sufficient heat to melt urea crystals despite the cooling jacket's heat dissipation effect. This parameter adjustment allows the heating function to overcome the cooling jacket's thermal resistance.
2Temperature
If the electrical current is increased to heat the dosing module and melt urea crystals, then the temperature of the dosing module is improved, but the energy consumption is worsened
Solution Approach 1:
The patent implements periodic heating cycles rather than continuous high-power heating. The controller activates the heating element in cycles, supplying high current (at least 400mA) only when needed to melt crystals or maintain temperature, and reduces or stops heating when the temperature is sufficient. This periodic action reduces overall energy consumption while maintaining the ability to melt urea crystals when required.
3Ease of operation
If the dosing module is designed without a cooling jacket to facilitate heating, then the ease of heating the dosing module is improved, but the reliability of the dosing module under normal operating conditions is worsened
Solution Approach 1:
The patent makes the cooling jacket's thermal characteristics dynamic by controlling coolant flow rate and temperature based on operational requirements. During heating phases, the system reduces coolant flow or increases coolant temperature to minimize heat extraction, facilitating easier heating. During normal dosing operations, the cooling jacket resumes its full cooling function to prevent overheating. This dynamic adjustment allows the same cooling jacket structure to serve both cooling and heating facilitation purposes.
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 effectively melts urea crystals within the dosing module, ensuring uninterrupted urea supply to the exhaust passage, thereby enhancing the operation of the emission abatement system and maintaining compliance with stringent NOx emission standards.
Implementation Method 1
The means for heating the dosing module may be the coil. Application of electricity to the coil at the second level of energy causes the dosing module to change to the unblocked condition by heating the coil.
Implementation Method 2
The means for moving the armature may be a coil device. The coil device includes a coil. Application of electricity to the coil at the first level of energy may cause the armature to move from the first position to the second position.
Data Source
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AI summary
A dosing module (24) for an emissions abatement system (10), the dosing module (24) including an armature (46), means (50) for moving the armature (46) and a valve body (42) having an outlet (71); the dosing module (24) having an unblocked condition, in which the armature (46) is moveable between a first position, in which the outlet (71) is closed by the armature (46), and a second position, in which the armature (46) is spaced apart from the outlet (71), and wherein, in use, application of electricity to the means (50) for moving the armature (46) at a first level of energy causes the armature to move from the first position to the second position; the dosing module (24) further having a blocked (by urea crystallisation) condition, in which flow of a liquid through the outlet (71) is prevented, wherein, in use, application of electricity to the means (50) for moving the armature (46) at a second level of energy causes the dosing module to change to the unblocked condition by melting the urea crystals to a temperature of at least 100°C. The heating device can be the solenoid coil of the actuator or a separate heating coil.