Exhaust emission control system and purification control device

Patent metadata

Field	Value
Publication number	US-10378406-B2
Application number	US-201615150911-A
Country	US
Kind code	B2
Filing date	May 10, 2016
Priority date	May 12, 2015
Publication date	Aug 13, 2019
Grant date	Aug 13, 2019

Abstract

An exhaust emission control apparatus is provided with a supply device, a catalyst, and a gas pressure reduction part. The supply device supplies a reducing agent to an exhaust passage. The catalyst purifies an exhaust gas by the use of the reducing agent. The gas pressure reduction part can make a gas pressure near the supply port lower than the gas pressure on the inside of a supply device body. A NOx catalyst adsorbs nitrogen oxide contained in the exhaust. NOx adsorbed by the NOx catalyst is desorbed from the NOx catalyst when the exhaust gas is purified. An ECU estimates an adsorption amount of NOx. Then, the ECU estimates a desorption amount of NOx desorbed from the NOx catalyst on the basis of the estimated adsorption amount of NOx.

First claim

What is claimed is:

1. An exhaust emission control system comprising:
a fuel reformation device that generates a reducing agent to reduce nitrogen oxide contained in an exhaust gas emitted from an engine by reforming fuel used for the engine;
a catalyst that purifies the nitrogen oxide in the exhaust gas by the use of the reducing agent supplied by the fuel reformation device;
a plurality of degradation sensing parts that are arranged in the catalyst along a flow direction of the exhaust gas and that sense a physical quantity relating to degradation of the catalyst;
a degradation estimation part that produces a degradation distribution of the catalyst in the flow direction on the basis of sensed values of the plurality of degradation sensing parts and that estimates a portion which is less degraded of the catalyst from the degradation distribution; and
a reformation control part that controls reformation of the fuel by the fuel reformation device to have the reducing agent to reach the portion of the catalyst, which is estimated to be less degraded by the degradation estimation part, in an active state,
wherein the reformation control part controls the reformation of the fuel to control, as a portion, in which degradation progresses, of the catalyst expands to a downstream side along the flow direction, activity of the reducing agent supplied from the fuel reformation device to be reduced.

2. The exhaust emission control system according to claim 1 ,
wherein the fuel reformation device has a fuel injection part that injects the fuel, and
wherein the reformation control part reduces the activity of the reducing agent by a control to increase a fuel amount injected per unit time from the fuel injection part.

3. The exhaust emission control system according to claim 1 ,
wherein the fuel reformation device has a temperature elevation part that elevates a temperature of the fuel, and
wherein the reformation control part reduces the activity of the reducing agent by a control to decrease the temperature of the fuel by the temperature elevation part.

4. The exhaust emission control system according to claim 1 ,
wherein the plurality of degradation sensing parts sense temperatures of a plurality of portions of the catalyst, respectively, and
wherein the degradation estimation part compares catalyst temperatures sensed by the respective degradation sensing parts with base temperatures indicated by the catalyst which is not yet degraded and estimates a portion in which the sensed catalyst temperature is low as a portion in which degradation progresses.

5. The exhaust emission control system according to claim 4 ,
wherein in the case where the reformation control part corrects a reforming state of the fuel in accordance with a degree of degradation of the catalyst which is estimated by the degradation estimation part, the reformation control part adjusts the reforming state of the fuel supplied to the catalyst by the use of the catalyst temperatures sensed by the respective degradation sensing parts.

6. The exhaust emission control system according to claim 1 ,
wherein in the case where a previously set diagnosis start condition is established, the reformation control part makes the fuel reformation device start a supply of the reducing agent so as to estimate degradation of the catalyst.

7. The exhaust emission control system according to claim 1 , further comprising:
an information acquisition part that acquires driving information to indicate a driving state of the engine in time series; and
a steadiness determination part that determines whether or not the engine is in a steady state on the basis of a transition of the driving information acquired by the information acquisition part,
wherein in the case where the steadiness determination part determines that the engine is in the steady state, the degradation estimation part starts to estimate degradation of the catalyst.

8. The exhaust emission control system according to claim 1 , further comprising:
a fresh air introduction part that introduces air into the fuel reformation device,
wherein the reformation control part controls an introduction of the air by the fresh air introduction part in such a way that the reducing agent in an active state reaches a portion which is less degraded of the catalyst.

9. An exhaust emission control system comprising:
a fuel reformation device that generates a reducing agent to reduce nitrogen oxide contained in an exhaust gas emitted from an engine by reforming fuel used for the engine;
a catalyst that purifies the nitrogen oxide in the exhaust gas by the use of the reducing agent supplied by the fuel reformation device;
a plurality of degradation sensing parts that are arranged in the catalyst along a flow direction of the exhaust gas and that sense a physical quantity relating to degradation of the catalyst;
a degradation estimation part that produces a degradation distribution of the catalyst in the flow direction on the basis of sensed values of the plurality of degradation sensing parts and that estimates a portion which is less degraded of the catalyst from the degradation distribution; and
a reformation control part that controls reformation of the fuel by the fuel reformation device to have the reducing agent to reach the portion of the catalyst, which is estimated to be less degraded by the degradation estimation part, in an active state;
wherein when the degradation estimation part estimates that a portion on a downstream side in the flow direction of the catalyst degrades, the reformation control part controls the reformation of the fuel to increase the activity of the reducing agent supplied from the fuel reformation device.

10. The exhaust emission control system according to claim 9 ,
wherein the fuel reformation device has a fuel injection part that injects the fuel, and
wherein the reformation control part increases the activity of the reducing agent by a control to decrease a fuel amount injected per unit time from the fuel injection part.

11. The exhaust emission control system according to claim 9 ,
wherein the fuel reformation device has a temperature elevation part that elevates a temperature of the fuel, and
wherein the reformation control part increases the activity of the reducing agent by a control to increase the temperature of the fuel by the temperature elevation part.

12. An exhaust emission control system comprising:
a fuel reformation device that generates a reducing agent to reduce nitrogen oxide contained in an exhaust gas emitted from an engine by reforming fuel used for the engine;
a catalyst that purifies the nitrogen oxide in the exhaust gas by the use of the reducing agent supplied by the fuel reformation device;
a plurality of degradation sensing parts that are arranged in the catalyst along a flow direction of the exhaust gas and that sense a physical quantity relating to degradation of the catalyst;
a degradation estimation part that produces a degradation distribution of the catalyst in the flow direction on the basis of sensed values of the plurality of degradation sensing parts and that estimates a portion which is less degraded of the catalyst from the degradation distribution;
a reformation control part that controls reformation of the fuel by the fuel reformation device to have the reducing agent to reach the portion of the catalyst, which is estimated to be less degraded by the degradation estimation part, in an active state; and
a reducing agent sensing part that is positioned between the fuel reformation device and the catalyst and that senses a state of the reducing agent supplied from the fuel reformati

Assignees

• Denso Corp

Inventors

• Furukawa Kengo
• Hongo Yusuke
• Osaka Jun
• Uchiyama Yoshiho
• Itou Takamasa
• Kondoh Wakichi
• Takeyama Masaki
• Motoo Kohei

Classifications

• F01N2610/1453

  Sprayers or atomisers; Arrangement thereof in the exhaust apparatus · CPC title

• F01N2240/20

  a flow director or deflector · CPC title

• Y02T10/24

  Cross-Sectional Technologies · mapped topic

• F01N3/2066 Primary

  Selective catalytic reduction [SCR] · CPC title

• F01N2610/03

  the substance being hydrocarbons, e.g. engine fuel · CPC title