US 9,810,120 B2
Exhaust gas purifying system
Hiroshi Akama, Zushi (JP); and Hitoshi Onodera, Yokosuka (JP)
Assigned to NISSAN MOTOR CO., LTD., Yokohama-shi (JP)
Appl. No. 12/671,056
Filed by Hiroshi Akama, Zushi (JP); and Hitoshi Onodera, Yokosuka (JP)
PCT Filed Jul. 29, 2008, PCT No. PCT/JP2008/002015
§ 371(c)(1), (2), (4) Date Jan. 28, 2010,
PCT Pub. No. WO2009/016822, PCT Pub. Date Feb. 5, 2009.
Claims priority of application No. 2007-201016 (JP), filed on Aug. 1, 2007; and application No. 2008-103684 (JP), filed on Apr. 11, 2008.
Prior Publication US 2010/0199635 A1, Aug. 12, 2010
Int. Cl. F01N 3/00 (2006.01); F01N 3/20 (2006.01); F01N 3/08 (2006.01); F01N 9/00 (2006.01); F01N 11/00 (2006.01); F02D 41/02 (2006.01); F01N 13/00 (2010.01)
CPC F01N 3/2013 (2013.01) [F01N 3/0807 (2013.01); F01N 3/0814 (2013.01); F01N 3/0835 (2013.01); F01N 3/0842 (2013.01); F01N 3/0871 (2013.01); F01N 9/00 (2013.01); F01N 11/007 (2013.01); F01N 13/009 (2014.06); F02D 41/0275 (2013.01); F01N 2240/16 (2013.01); F01N 2370/04 (2013.01); F01N 2430/06 (2013.01); F01N 2510/06 (2013.01); F01N 2510/063 (2013.01); F01N 2510/0682 (2013.01); F01N 2560/023 (2013.01); F01N 2560/026 (2013.01); F01N 2570/12 (2013.01); F01N 2570/14 (2013.01); F02D 2200/0806 (2013.01); Y02T 10/24 (2013.01); Y02T 10/26 (2013.01); Y02T 10/47 (2013.01)] 7 Claims
OG exemplary drawing
 
1. An exhaust gas purifying system for an internal combustion engine, the system comprising: a NOx trapping agent which adsorbs nitrogen oxide when an excess air ratio of exhaust gas is more than 1, and releases nitrogen oxide when the excess air ratio is 1 or less; a NOx purifying catalyst which reduces nitrogen oxide to nitrogen; a HC trapping agent which adsorbs and releases hydrocarbons; and a CPU comprising instructions such that the CPU: controls oxygen concentration in the exhaust gas, controls the excess air ratio of the exhaust gas to be between 0.75 to 0.83 and when the excess air ratio of the exhaust gas is between 0.75 and 0.83, controls the oxygen concentration of the exhaust gas at an inlet of the NOx purifying catalyst between 1.1 and 1.2% by volume to enhance a partially-oxidized reaction of hydrocarbons in the exhaust gas, wherein a HC trapping agent layer containing the HC trapping agent is formed on a monolithic substrate, and a NOx trap-purifying catalyst layer containing the NOx trapping agent and the NOx purifying catalyst is formed on the HC trapping agent layer.