Exhaust purification system and method for controlling exhaust purification system

Patent metadata

Field	Value
Publication number	US-9255511-B2
Application number	US-201113997608-A
Country	US
Kind code	B2
Filing date	Dec 21, 2011
Priority date	Dec 27, 2010
Publication date	Feb 9, 2016
Grant date	Feb 9, 2016

Abstract

Provided is an exhaust purification system capable of clearing a blockage of a reducing agent injection valve caused by solidification of an aqueous urea solution soon after starting an engine and preventing degradation in exhaust purification efficiency when starting an internal combustion engine. An exhaust purification system with a DPF, a reducing agent injection valve, and an SCR catalyst in order from the exhaust upstream side includes: an operation state detecting unit capable of detecting starting and stopping of the internal combustion engine; a forced regeneration control unit which performs forced regeneration of the DPF; a condition establishment determining unit which determines whether there is a possibility of solidification of the aqueous urea solution when the operation state detecting unit detects that the internal combustion engine is stopped; a data storage unit which stores the determination result of the condition establishment determining unit as data; and a blockage-clearing control unit which controls a temperature raising unit for raising the temperature of the reducing agent injection valve so as to raise the temperature of the reducing agent injection valve based on the data when starting the internal combustion engine.

First claim

The invention claimed is:

1. An exhaust purification system with a DPF which collects exhaust particulates in an exhaust gas, a reducing agent injection valve which injects an aqueous urea solution as a reducing agent into the exhaust gas, and an SCR catalyst which purifies a NOx in the exhaust gas by using the aqueous urea solution, the DPF, the reducing agent injection valve and the SCR catalyst being provided in sequence from the exhaust upstream side, the exhaust purification system comprising:
an operation state detecting unit configured to detect starting and stopping of an internal combustion engine;
a condition establishment determining unit which determines whether there is a possibility of solidification of the aqueous urea solution when the operation state detecting unit detects the stopping of the internal combustion engine;
a data storage unit which stores a determination result of the condition establishment determining unit as data; and
a blockage-clearing control unit which activates a forced regeneration unit of the DPF for raising a temperature of the reducing agent injection valve based on the determination result from the data storage unit when starting the internal combustion engine so as to raise the temperature of the reducing agent injection valve.

2. The exhaust purification system according to claim 1 ,
wherein the condition establishment determining unit determines that there is a possibility of solidification of the aqueous urea solution when the stopping of the internal combustion engine is detected while forced regeneration of the DPF is started and ended or within a predetermined period after the forced regeneration is ended.

3. The exhaust purification system according to claim 1 ,
wherein the condition establishment determining unit determines whether there is a possibility of solidification of the aqueous urea solution based on at least one of a temperature of the reducing agent injection valve, a temperature gradient, and an external air temperature when the stopping of the internal combustion engine is detected.

4. A method for controlling an exhaust purification system with a DPF which collects exhaust particulates in an exhaust gas, a reducing agent injection valve which injects an aqueous urea solution as a reducing agent into the exhaust gas, and an SCR catalyst which purifies a NOx in the exhaust gas by using the aqueous urea solution, the DPF, the reducing agent injection valve and the SCR catalyst being provided in order from the exhaust upstream side, the method comprising:
determining whether there is a possibility of solidification of the aqueous urea solution when stopping of an internal combustion engine is detected and storing a determination result as data; and
activating a forced regeneration unit of the DPF for raising the temperature of the reducing agent injection valve so as to raise the temperature of the reducing agent injection valve when stored is the data representing the determination result in which there is a possibility of solidification of the aqueous urea solution when starting the internal combustion engine.

5. An exhaust purification system with a DPF which collects exhaust particulates in an exhaust gas, a reducing agent injection valve which injects an aqueous urea solution as a reducing agent into the exhaust gas, and an SCR catalyst which purifies a NOx in the exhaust gas by using the aqueous urea solution, the DPF, the reducing agent injection valve and the SCR catalyst being provided in sequence from the exhaust upstream side, the exhaust purification system comprising:
a computer configured to
detect starting and stopping of an internal combustion engine, and
determine a likelihood of solidification of the aqueous urea solution when stopping of the internal combustion engine is detected and generate a determination result of the likelihood of solidification; and

a data storage unit connected to the computer and which stores the determination result as data;
wherein the computer is further configured to activate a fuel injection valve to supply fuel into an exhaust pipe positioned upstream of the DPF to raise a temperature of the reducing agent injection valve based on the data stored in the data storage unit when starting the internal combustion engine.

Assignees

• Watanabe Masanori
• Miyamoto Takeshi
• Kurogi Fumiyasu
• Bosch Corp

Inventors

• Watanabe Masanori
• Miyamoto Takeshi
• Kurogi Fumiyasu

Classifications

• F01N3/023

  using means for regenerating the filters, e.g. by burning trapped particles · CPC title

• F01N2900/0402

  using adaptive learning · CPC title

• F01N2900/1811

  Temperature · CPC title

• F01N2430/00

  Influencing exhaust purification, e.g. starting of catalytic reaction, filter regeneration, or the like, by controlling engine operating characteristics · CPC title

• F01N2610/105

  Control thereof · CPC title