Reagent Dosing Pump Cooling Jacket for SCR Systems
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Solution Overview
Problem
Reagent dosing pumps in selective catalytic reduction systems face overheating issues due to exposure to high exhaust gas temperatures, leading to urea precipitation and inefficient NOx emission reduction, especially when mounted closer to the engine where cooling is more challenging.
Innovation Solution
A pump assembly with a cooling jacket arrangement that includes a flow guide to optimize cooling fluid flow around the pump housing and nozzle, ensuring efficient heat transfer and preventing reagent overheating, while also bracing the pump housing against reagent expansion risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the reagent dosing pump is mounted close to the exhaust system to reduce NOx emissions, then the efficiency of NOx reduction is improved, but the reagent is exposed to high temperatures causing urea precipitation and system blockages
Solution Approach 1:
A cooling jacket is introduced as an intermediary component between the reagent dosing pump and the hot exhaust environment. The cooling jacket circulates coolant to absorb heat from the pump housing, preventing thermal transfer to the reagent. This mediator protects the reagent from high temperatures while allowing the pump to remain positioned for effective NOx reduction.
2Device complexity
If the reagent dosing pump is located in the engine compartment for compact installation, then the device complexity is reduced, but the reagent is exposed to higher temperatures making cooling more difficult
Solution Approach 1:
The cooling jacket serves as a thermal barrier that enables the pump to be installed in the engine compartment without direct thermal exposure. The coolant circulating through the jacket absorbs heat from the pump housing, acting as a mediator that decouples the pump's physical location from its thermal environment, allowing compact installation while maintaining reagent temperature control.
3Temperature
If cooling means are added to prevent reagent overheating, then the reagent temperature is controlled, but the device complexity increases
Solution Approach 1:
The cooling jacket is merged with the pump housing to form an integrated assembly. The jacket is formed as a single piece that encapsulates the pump housing, combining the pumping function with the cooling function in one unified structure. This integration reduces the number of separate components and simplifies assembly, offsetting the added complexity of the cooling system.
Solution Approach 2:
The cooling jacket serves multiple functions simultaneously: it provides thermal protection to the reagent, structurally braces the pump housing against expansion, and acts as a mounting interface. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in overall device complexity while achieving temperature control.
4Strength
If the pump housing is braced against expansion, then the structural integrity is improved, but the device complexity increases
Solution Approach 1:
The bracing function is merged into the cooling jacket structure itself. The jacket is designed with rigid walls that mechanically constrain the pump housing, preventing thermal expansion. By combining the cooling and bracing functions in a single component, the structural support feature is added without requiring separate bracing elements, thus minimizing the increase in device complexity.
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 cooling jacket arrangement effectively prevents reagent overheating and urea precipitation, maintaining the reagent's concentration and ensuring efficient NOx emission reduction, while also protecting the pump from reagent freezing-induced damage.
Implementation Method 1
cooling fluid is caused to flow through the first compartment in a first direction generally parallel to the pump axis, and through the second compartment in a second direction generally opposite to the first direction
Data Source
Figure 1
Figure 2
Figure 3~4(b)
AI summary
A pump assembly (100) having improved cooling for use in a selective catalytic reduction system is disclosed. The pump assembly comprises a pump housing (104) having a body portion (106) and a nozzle portion (108) extending from the body portion (106), a jacket (130) including a cavity (132) for receiving the pump housing (104), first and second ports (232, 230) for cooling fluid, and a flow guide (200) disposed between the jacket (130) and the pump housing (104). The cavity (132) includes a first compartment (220) for cooling fluid defined in part by the flow guide(200) and in part by the pump housing (104) and being in fluid communication with the first port (230); and a second compartment (224) for cooling fluid defined in part by the flow guide (200) and in part by the jacket (130). The first compartment (220) is in fluid communication with the second port (232) by way of the second compartment (224).