SYSTEMS AND TECHNIQUES FOR NOZZLE COOLING OF DIESEL EXHAUST FLUID INJECTION SYSTEMS

摘要

A system is provided for delivery of diesel exhaust fluid or other reductant to an injector for release into an engine exhaust aftertreatment system. The injector includes a nozzle assembly that thermally shields the diesel exhaust fluid from the exhaust gas temperatures. A diesel exhaust fluid delivery procedure is also disclosed for nozzle cooling prior to operation of the injector for emissions reduction.

主权项

1. A method, comprising:
cooling a nozzle that is directly connected to an exhaust system that receives exhaust gas from an engine by completing a nozzle cooling cycle of operation of a reductant delivery system that provides reductant to the nozzle for injection into the exhaust system, wherein completing the nozzle cooling cycle includes injecting one or more pulses of the reductant through the nozzle in a first amount that substantially phase transforms the reductant to cool the nozzle to less than a threshold temperature prior to initiating an emissions reduction cycle of operation in which the reductant is injected through the nozzle in a second amount that is greater than the first amount to reduce emissions in the exhaust gas.