Apparatus for an exhaust aftertreatment system and method of controlling reductant flow in an apparatus for an engine exhaust aftertreatment system

Abstract

A device (100) for an exhaust gas aftertreatment system (102), the device comprising: a tank (104) for storing a reducing agent (106); a pump unit device (108) arranged in the downstream of and in fluid communication with a tank; a nozzle (110) arranged to inject a flow of reductant into the exhaust aftertreatment system (102), the nozzle being disposed downstream of the tank and passing through a reductant conduit (112 ), in fluid communication with the tank via a pump unit device; an air conduit (114), which is arranged in fluid communication with a nozzle (110) to deliver compressed air to the nozzle; and a return conduit (116), which arranged in fluid communication between a reductant conduit and the tank, the return conduit comprising a return conduit valve arrangement (118), wherein an air conduit (114) is arranged in fluid communication with the reductant conduit (112) to Reductant is controllably delivered to the tank via return conduit valve means (118) by providing compressed air from the air conduit to the reductant conduit.

Description

technical field [0001] The invention relates to a device for an exhaust gas aftertreatment system. The invention also relates to a method of controlling the flow of reducing agent in a device for an exhaust gas aftertreatment system. The present invention is applicable to vehicles, particularly light, medium and heavy duty vehicles commonly referred to as trucks, however, other types of vehicles that use a reducing agent on the exhaust may also use the apparatus and method of the present invention. Background technique [0002] With regard to the exhaust gas aftertreatment of the exhaust gas from internal combustion engines, selective catalytic reduction systems (SCR) are generally used. These systems use liquid reducing agents such as ammonia, urea, etc. Thus, reducing agent is injected into the SCR through nozzles or the like. Provides a chemical reaction between the exhaust from the engine and the reductant, which reduces the final NO emitted from the aftertreatment sy...

AI Technical Summary

Problems solved by technology

[0004] One problem with equipment for reducing agents such as ammonia and urea is the relatively high freezing temperature of these reducing agents

Another problem with prior art devices for reductant delivery is that when the system is temporarily out of service, solid deposits can form and remain in all parts of the system, which deposits can interfere with reductant delivery during subsequent operations operate

Images