Title:
EXHAUST EMISSION CONTROL DEVICE FOR ENGINE
Document Type and Number:
Japanese Patent JP3885331
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To improve both fuel consumption and operability compared to the case of providing an exhaust passage with only one NOx occluding type catalyst.
SOLUTION: A plurality of NOx occluding type catalysts are series-arranged in an exhaust passage 31. At the time of lean operation, a computing means 34 computes the NOx occlusion quantity of the upper reaches catalyst 32, and the lean operation time NOx occlusion quantity of the lower reaches catalyst 33 in the case of the NOx occlusion quantity of the catalyst 32 becoming the occlusion limit. In the case of coming to timing for specified enrichment processing, a setting means 35 sets the degree of enrichment according to the occluded NOx quantity at the time of only the upper reaches catalyst 32 occluding NOx and according to the sum of the occluded NOx quantity of the upper reaches catalyst 32 and the occluded NOx quantity of the lower reaches catalyst 33 at the time of NOx being occluded by the lower reaches catalyst 33 in addition to the upper reaches catalyst 32.
Inventors:
Koichi Mori
Application Number:
JP1686898A
Publication Date:
February 21, 2007
Filing Date:
January 29, 1998
Export Citation:
Assignee:
Nissan Motor Co., Ltd
International Classes:
F01N3/08; F02D41/14; F01N3/20; F01N3/24; F01N3/28; F02D41/04; (IPC1-7): F02D41/14; F02D41/14; F01N3/08; F01N3/20; F01N3/24; F01N3/24; F01N3/28; F01N3/28; F02D41/04; F02D41/04
Domestic Patent References:
| JP6117221A | ||||
| JP9112308A | ||||
| JP7310534A | ||||
| JP6066185A |
Attorney, Agent or Firm:
Masaki Goto
Yoshio Matsuda
Yoshio Matsuda