DEF Injector Thermal Management via Auxiliary Power Purge
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Solution Overview
Problem
SCR systems face challenges such as injector component overheating due to proximity to hot exhaust, potential freezing of urea solutions, and corrosion issues, which can lead to component damage and system inefficiencies.
Innovation Solution
A power management system that includes a diesel exhaust fluid (DEF) injector with a coolant passage, a DEF pump, and an auxiliary power unit to maintain power after engine shutdown, enabling thermal management and purging of the injector, using stored electrical energy to activate cooling systems and purge the DEF fluid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the DEF injector is positioned close to the exhaust system for continuous DEF supply, then the injection efficiency is improved, but the injector components are exposed to overheating risks
Solution Approach 1:
A coolant passage is integrated into the DEF injector housing, serving as an intermediary cooling channel that allows coolant to flow through and absorb heat from the injector components, thereby protecting them from overheating while maintaining close proximity to the exhaust system for efficient DEF injection
2Loss of energy
If the engine electrical system is deactivated during shutdown to save energy, then the energy consumption is reduced, but the ability to perform cooling and purging operations is lost
Solution Approach 1:
The auxiliary power unit is charged with electrical energy during engine operation, storing energy in advance so that it can power the coolant pump and fan for cooling and purging operations after the engine shutdown when the main electrical system is deactivated
Solution Approach 2:
The system transitions from using the main engine electrical system during operation to using the auxiliary power unit after shutdown, changing the power source parameter to maintain essential cooling and purging functions while reducing overall energy consumption
3Temperature
If active cooling systems are used during engine operation, then the injector temperature is controlled, but the system complexity increases
Solution Approach 1:
The coolant passage integrated into the DEF injector housing serves multiple functions: it cools the injector during engine operation and enables purging of residual DEF after shutdown, reducing the need for separate dedicated cooling and purging systems
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 system effectively prevents overheating and freezing issues by maintaining power for cooling and purging operations after engine shutdown, ensuring the longevity and functionality of SCR system components.
Implementation Method 1
The coolant passage is adapted to accommodate a flow of coolant for cooling the DEF injector
Implementation Method 2
storing electrical energy in an auxiliary power unit from the electrical system during engine operation
Data Source
AI summary
A machine includes an engine having a coolant system, an electrical system, and an exhaust system. A diesel exhaust fluid (DEF) injector provides DEF into the exhaust system. The DEF injector includes a housing that forms a coolant passage therethrough. The coolant passage is adapted to accommodate a flow of coolant through the coolant passage for cooling the DEF injector. A DEF pump is arranged to provide DEF to the DEF injector from a reservoir during operation of the engine. A power management module is associated with the electrical system, the DEF injector and the DEF pump. An auxiliary power unit is associated with the power management module and is configured to remain active after the engine electrical system has been deactivated. The power management module is configured to cause a purge of the DEF from the DEF injector when the engine is shut down.