Improvements in predicting the freezing behavior of SCR dosing systems

Abstract

Many SCR dosing systems are used in regions of the world that experience temperatures below that at which the “Diesel Exhaust Fluid” used in the SCR chemical reaction freezes. During freezing, expansion of the fluid can cause damaging pressures in confined cavities. Some dosing system designs require a “purge” cycle when the system is shut down to prevent this. The Cummins EcoFit™ design eliminates the need for a purge with low-stiffness internal expansion elements. Placement of the expansion elements is nontrivial. Transient thermal and quasistatic structural analyses are used to shorten the design cycle and produce a product robust under varied application conditions. This paper provides a simple example of the use of a mesh free discretization method, the “Finite Point Method” to reduce the time required to set up and execute the thermal and structural analyses used in design of a passively freeze-robust component.