DEVELOPMENT OF COOLING CHARACTERISTICS OF UREA-WATER SOLUTION DOSING MODULES FOR AUTOMOTIVE SCR SYSTEMS

International regulations are challenging automotive industry to develop more efficient systems for reducing diesel engines NOx emissions. Selective Catalytic Reduction systems may be a concrete solution, in fact SCR systems are already on the market, firstly developed for heavy duty diesel engine applications, and now it is beginning the spreading to light automotive applications.

The urea-water solution dosing module may be subjected to strong heat transfer, so an efficient heat dissipation is crucial step to avoid injector's severe damages, as deformations of internal components or solenoid's fault. To have a system less complex and consequently less expensive, the dosing module air cooling should be preferred to liquid cooling. Obtain an efficient heat dissipation from the injector holder unit can represent a hard task: consequently dosing module design must be careful.

In this paper is presented an experimental and numerical analysis for different possible solutions to be implemented in order to ensure in all conditions an efficient heat dissipation. Particular attention is paid to thermal characteristics of materials and to peculiar heat transfer paths that can be set-up and exploited to fulfill the task. In this paper are discussed the different design solutions considered and respective performance.