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:
determining a temperature of a nozzle in a diesel exhaust fluid delivery system, the diesel exhaust fluid delivery system including a storage tank for storing a source of diesel exhaust fluid and a doser operable to pump a measured quantity of the diesel exhaust fluid from the storage tank through the nozzle into an exhaust system of an internal combustion engine; when the temperature of exhaust gas in the exhaust system exceeds a predetermined temperature threshold, initiating a nozzle cooling cycle of operation of the doser in which the diesel exhaust fluid from the storage tank is injected through the nozzle in one or more pulses to cool the nozzle with the diesel exhaust fluid; terminating the nozzle cooling cycle of operation of the doser when the temperature of the nozzle is less than the predetermined temperature threshold; delaying pumping of diesel exhaust fluid from the storage tank with the doser for a predetermined time period after terminating the nozzle cooling cycle of operation; and after the predetermined time period elapses, initiating an emissions reduction cycle of operation of the doser in which diesel exhaust fluid from the storage tank is pumped by the doser through the nozzle in an amount determined to reduce emissions from the exhaust gas.