Exhaust gas control apparatus for internal combustion engine

Patent metadata

Field	Value
Publication number	US-9221017-B2
Application number	US-201114110895-A
Country	US
Kind code	B2
Filing date	Jul 4, 2011
Priority date	Jul 4, 2011
Publication date	Dec 29, 2015
Grant date	Dec 29, 2015

Abstract

The purpose of the present invention is to suppress degradation of a PM sensor and a decrease in detection accuracy of the amount of PM in a configuration in which a urea addition unit and a selective reduction-type NOx catalyst (NOx catalyst) are provided downstream of a particulate filter (filter) in an internal combustion engine exhaust passage, the PM sensor being disposed downstream of the filter. According to the present invention, in an exhaust passage ( 2 ) of an internal combustion engine ( 1 ), a first NOx catalyst ( 4 ) and a second NOx catalyst ( 5 ) are disposed downstream of a filter ( 3 ) successively from the upstream side along the flow of exhaust. A urea addition unit ( 6 ) is disposed between the filter ( 3 ) and the first NOx catalyst ( 4 ). A PM sensor ( 7 ) is disposed between the first NOx catalyst ( 4 ) and the second NOx catalyst ( 5 ).

First claim

The invention claimed is:

1. An exhaust gas control apparatus for an internal combustion engine, comprising:
a particulate filter that is provided in an exhaust passage of the internal combustion engine;
a first selective reduction-type NOx catalyst that is provided in the exhaust passage downstream of the particulate filter;
a second selective reduction-type NOx catalyst that is provided in the exhaust passage downstream of the first selective reduction-type NOx catalyst;
a urea addition unit that is provided in the exhaust passage between the particulate filter and the first selective reduction-type NOx catalyst to add urea into exhaust gas; and
a PM sensor that is provided in the exhaust passage between the first selective reduction-type NOx catalyst and the second selective reduction-type NOx catalyst to detect an amount of a particulate matter in exhaust gas.

2. The exhaust gas control apparatus for the internal combustion engine according to claim 1 , wherein a heat capacity of the first selective reduction-type NOx catalyst is smaller than a heat capacity of the second selective reduction-type NOx catalyst.

Assignees

• Nakano Takanori
• Katayama Haruyuki
• Hirota Shinya
• Toshioka Shunsuke
• Fukuda Koichiro
• Toyota Motor Co Ltd

Inventors

• Nakano Takanori
• Katayama Haruyuki
• Hirota Shinya
• Toshioka Shunsuke
• Fukuda Koichiro

Classifications

• F01N13/0093

  the purifying devices are of the same type · CPC title

• B01D2255/904

  Multiple catalysts · CPC title

• B01D53/9495

  Controlling the catalytic process · CPC title

• F01N3/035 Primary

  with catalytic reactors · CPC title

• B01D53/9431 Primary

  Processes characterised by a specific device · CPC title