Exhaust purification system

Patent metadata

Field	Value
Publication number	US-10675587-B2
Application number	US-201615558180-A
Country	US
Kind code	B2
Filing date	Mar 8, 2016
Priority date	Mar 13, 2015
Publication date	Jun 9, 2020
Grant date	Jun 9, 2020

Abstract

An exhaust purification system including a NOx catalyst 32 provided in an exhaust passage of an internal combustion engine 10 and purifying NOx in exhaust; a MAF sensor 40 for acquiring an air flow-rate of the internal-combustion engine 10; a control unit 60, 70 that execute catalyst regeneration treatment of recovering a NOx purification ability of the NOx catalyst 32 by performing, in combination, air-based control of reducing air flow-rate of the internal-combustion engine 10 to a predetermined target air flow-rate and injection-based control of increasing a fuel injection amount, wherein, in a case of executing the catalyst regeneration treatment, the control unit 60, 70 starts with the air-based control and starts the injection-based control when the air flow-rate acquired by the MAF sensor 40 is reduced to the target air flow-rate.

First claim

The invention claimed is:

1. An exhaust purification system comprising:
a NOx catalyst provided in an exhaust passage of an internal combustion engine and configured to purify NOx in exhaust;
acquisition means for acquiring an air flow-rate of the internal combustion engine; and
catalyst regeneration means for executing catalyst regeneration treatment of recovering a NOx purification capacity of the NOx catalyst by performing, in combination, air-based control of reducing the air flow-rate of the internal combustion engine to a predetermined target air flow-rate and injection-based control of increasing a fuel injection amount,
wherein, in a case of executing the catalyst regeneration treatment, the catalyst regeneration means starts with the air-based control so as to lower an air excess ratio from a value upon normal operation to a first target air excess ratio, and starts the injection-based control so as to lower the air excess ratio from the first target air excess ratio to a second target air excess ratio after the air flow-rate acquired by the acquisition means is reduced to the predetermined target air flow-rate, and
wherein after starting the injection-based control, the catalyst regeneration means continues the injection-based control in a case when an increased amount of the air flow-rate acquired by the acquisition means relative to the target air flow-rate is equal to or smaller than a predetermined threshold value, and forcibly ends the injection-based control in a case where the increased amount of the air flow-rate acquired by the acquisition means relative to the target air flow-rate exceeds the predetermined threshold value.

2. An exhaust purification system comprising:
a NOx catalyst provided in an exhaust passage of an internal combustion engine and configured to purify NOx in exhaust;
an air flow sensor configured to acquire an air flow-rate of the internal combustion engine; and
a controller,
wherein the controller is operated to execute catalyst regeneration treatment of recovering a NOx purification capacity of the NOx catalyst by performing, in combination, air-based control of reducing the air flow-rate of the internal combustion engine to a predetermined target air flow-rate and injection-based control of increasing a fuel injection amount,
wherein, in a case of executing the catalyst regeneration treatment, the controller starts with the air-based control so as to lower an air excess ratio from a value upon normal operation to a first target air excess ratio, and starts the injection-based control so as to lower the air excess ratio from the first target air excess ratio to a second target air excess ratio after the air flow-rate acquired by the air flow sensor is reduced to the predetermined target air flow-rate, and
wherein after starting the injection-based control, the controller continues the injection-based control in a case where an increased amount of the air flow-rate acquired by the air flow sensor relative to the target air flow-rate is equal to or smaller than a predetermined threshold value, and forcibly ends the injection-based control in a case where the increased amount of the air flow-rate acquired by the air flow sensor relative to the target air flow-rate exceeds the predetermined threshold value.

3. An exhaust purification system comprising:
a NOx catalyst provided in an exhaust passage of an internal combustion engine and configured to purify NOx in exhaust;
an air flow sensor configured to acquire an air flow-rate of the internal combustion engine; and
a controller,
wherein the controller is operated to execute catalyst regeneration treatment of recovering a NOx purification capacity of the NOx catalyst by performing, in combination, air-based control of reducing the air flow-rate of the internal combustion engine to a predetermined target air flow-rate and injection-based control of increasing a fuel injection amount,
wherein, in a case of executing the catalyst regeneration treatment, the controller starts with the air-based control and starts the injection-based control when the air flow-rate acquired by the air flow sensor is reduced to the predetermined target air flow-rate, and
wherein after starting the injection-based control, the controller continues the injection-based control in a case where an increased amount of the air flow-rate acquired by the air flow sensor relative to the target air flow-rate is equal to or smaller than a predetermined threshold value, and forcibly ends the injection-based control in a case where the increased amount of the air flow-rate acquired by the air flow sensor relative to the target air flow-rate exceeds the predetermined threshold value.

Assignees

• Isuzu Motors Ltd

Inventors

• Nakada Teruo
• Sakamoto Takayuki
• Nagaoka Daiji
• Yuza Hiroyuki

Classifications

• F02D41/405

  with post injections · CPC title

• F02D41/0275

  the exhaust gas treating apparatus being a NOx trap or adsorbent · CPC title

• F02D2200/602

  Pedal position · CPC title

• F02D41/3064

  with special control during transition between modes · CPC title

• F01N3/0871

  using means for controlling, e.g. purging, the absorbents or adsorbents · CPC title