The control method of an exhaust gas aftertreatment apparatus

Japanese Patent JP6135198

B2

Provided is a method of controlling an exhaust gas aftertreatment device, which can properly control timing for returning to a rich state after S purge, and timing for spraying urea water after particulate matter (PM) regeneration. A DOC (25), a NOx occlusion reduction catalyst (26), and a DPF (27) are connected to an exhaust pipe (20) of an engine (E), downstream of an exhaust pipe injector (23) provided on the exhaust pipe (20). NOx in the exhaust gas is stored by the NOx occlusion reduction catalyst (26) when an air-fuel ratio is lean. The stored NOx is reduced and purified when the air-fuel ratio is rich. When a prescribed amount of PM has accumulated in the DPF (27), the exhaust gas temperature is raised to perform PM regeneration. The exhaust gas temperature is further raised to perform S purge to purge sulfur stored in the NOx occlusion reduction catalyst (26). The rich condition is prohibited during the PM regeneration period and the S purge period. When the S purge is completed, the rich condition prohibition continues until the difference between the inlet temperature of the DOC (25) and the outlet temperature of the NOx occlusion reduction catalyst (26) becomes equal to or less than a predetermined threshold.

Daiji Nagaoka
Teruo Nakata
Hiroyuki Yuza

JP2013045265A

May 31, 2017

March 07, 2013

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Isuzu Motors Limited

F01N3/36; F01N3/025; F01N3/08; F01N3/20

JP2006342735A
JP2002213232A
JP2004270470A
JP2004251177A
JP2008138619A
JP2008121629A
JP2006152947A

Nobuo Kinutani

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