Urea Doser Thermal Management via Integrated Heat Exchange Circuit
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Solution Overview
Problem
Selective catalytic reduction (SCR) systems for internal combustion engines face challenges in effectively heating urea solutions in cold weather, leading to inefficiencies and increased complexity in heating delivery systems.
Innovation Solution
A thermal management system with a heat exchange circuit connected to a heat source, featuring a control valve and controller to regulate the flow of heat exchange fluid, ensuring the urea solution in the storage tank and doser is maintained within specific temperature thresholds through controlled heat exchange cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple flow paths and valves are used in the heating distribution system to heat each portion of the SCR system independently, then the heating effectiveness is improved, but the device complexity and cost increase
Solution Approach 1:
The patent combines the heating of multiple SCR system components (storage tank, doser, injector) into a single integrated heat exchange circuit. The heat exchange fluid flows through all components sequentially, allowing one heating system to serve multiple functions that previously required separate heating paths and valves.
Solution Approach 2:
The heat exchange circuit is designed as a universal heating system that can simultaneously heat multiple different components (storage tank, doser, injector) through a single flow path. This multi-functional approach eliminates the need for component-specific heating systems while maintaining effective heating of all parts.
2Reliability
If electric heaters are used to heat the urea solution in the storage tank and doser, then the heating control is improved, but the device complexity and cost increase
Solution Approach 1:
The patent introduces heat exchange fluid as an intermediary medium to transfer thermal energy from a heat source to the urea solution. Instead of using electric heaters that directly contact the urea, the heat exchange fluid circulates through heat exchange circuits in the storage tank and doser, providing indirect but effective heating control.
Solution Approach 2:
The system uses a hydraulic heat exchange approach where a circulating fluid (heat exchange fluid) carries thermal energy through controlled flow paths. This hydraulic thermal transfer system replaces electrical heating elements while maintaining precise temperature control through flow rate management.
3Device complexity
If a simple heating system is used for the urea solution, then the device complexity is reduced, but the heating effectiveness in cold conditions deteriorates
Solution Approach 1:
The heating system is segmented into multiple heat exchange circuits, each serving specific components (storage tank circuit, doser circuit, injector circuit). This segmentation allows the simple single-fluid-flow architecture to effectively heat multiple discrete locations, maintaining heating effectiveness without requiring complex multi-system integration.
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 solution effectively heats the urea solution in the SCR system, ensuring optimal performance in cold conditions without the need for complex and costly heating systems, by efficiently managing temperature across the reductant delivery system.
Implementation Method 1
The flow path is routed from the heat source to a doser and then to a storage tank to provide thermal contact of the heat exchange fluid with the reductant in the doser and the storage tank
Implementation Method 2
a heat exchange circuit connected to a heat source, and the heat exchange circuit defines a flow path that is routed from the heat source to the doser, from the doser to the storage tank, from the storage tank to the doser, and from the doser to the heat source
Data Source
AI summary
A reductant delivery system is provided for delivery of reductant to an engine exhaust aftertreatment system that is heated during cold temperature conditions. A heat exchange fluid flows through a heat exchange circuit that provides a flow path from the heat source to the doser, from the doser to the reductant storage tank, and from the reductant storage tank to the heat source. A control valve controls the flow of the heat exchange fluid in the heat exchange circuit so that at least one heat exchange cycle includes a circulation period that increases the temperature of the reductant in the doser and storage tank and a termination period where circulation is stopped until reductant temperature in the doser reaches a lower limit.