Method for thermal control of exhaust aftertreatment

Patent metadata

Field	Value
Publication number	US-9611793-B2
Application number	US-201414451025-A
Country	US
Kind code	B2
Filing date	Aug 4, 2014
Priority date	Aug 4, 2014
Publication date	Apr 4, 2017
Grant date	Apr 4, 2017

Abstract

There is disclosed a method of regenerating at least one aftertreatment device in an exhaust system of an internal combustion engine by changing a calibration of the exhaust gas recirculation system with the engine to increase temperature of exhaust gas provided to the at least one aftertreatment device, and further incrementally changing the calibration to obtain an exhaust gas temperature within a target regeneration temperature range.

First claim

We claim:

1. A method of regenerating at least one aftertreatment device in an exhaust system of an internal combustion engine including an exhaust gas recirculation system, the method comprising:
determining if regeneration of the at least one aftertreatment device is needed;
changing a calibration of the exhaust gas recirculation system with the engine to increase temperature of exhaust gas provided to the at least one aftertreatment device;
determining if the temperature of the exhaust gas provided to the aftertreatment device is above a regeneration target temperature;
if the temperature of the exhaust gas provided to the aftertreatment device is above the regeneration target temperature, determining if a target regeneration has occurred after a regeneration period;
if the target regeneration has occurred, then ending regeneration;
if the target regeneration has not occurred, then determining if the calibration of the exhaust gas recirculation system with the engine is at a maximum level;
if the calibration of the exhaust gas recirculation system with the engine is not at the maximum level, then incrementally changing the calibration of the exhaust gas recirculation system with the engine to increase the temperature of the exhaust gas provided to the at least one aftertreatment device until such time as the target regeneration occurred or the calibration of the exhaust gas recirculation system with the engine is at the maximum level;
if the temperature of the exhaust gas provided to the aftertreatment device is not above the regeneration target temperature, then determining if the calibration of the exhaust gas recirculation system with the engine is at the maximum level;
if the calibration of the exhaust gas recirculation system with the engine is not at the maximum level, then incrementally changing the calibration of the exhaust gas recirculation system with the engine to increase the temperature of the exhaust gas provided to the at least one aftertreatment device until such time as the temperature of the exhaust gas provided to the aftertreatment device is above the regeneration target temperature and target regeneration has occurred, or until the calibration of the exhaust gas recirculation system with the engine is at the maximum level; and
if the target regeneration of the at least one aftertreatment device has not occurred, then adjusting a boost recirculation valve associate with an inlet air supply system to divert some compressed air from downstream a compressor in the inlet air supply system to upstream the compressor prior to determining if the calibration exhaust gas recirculation system with the engine is at the maximum level.

2. The method of claim 1 further including if the calibration of the exhaust gas recirculation system with the engine is at the maximum level, then adjusting the boost recirculation valve associated with the inlet air supply system to divert some compressed air from downstream the compressor in the inlet air supply system to upstream the compressor.

3. The method of claim 2 wherein the at least one aftertreatment device is a selective catalytic reduction device.

4. The method of claim 1 further including if the target regeneration has not occurred, then increasing the target regeneration temperature.

5. The method of claim 1 further including if the target regeneration has not occurred, then determining if an increase in the target regeneration temperature would be within a target regeneration temperature range, and, if so, then determining if the calibration of the exhaust gas recirculation system with the engine is at its maximum level.

6. The method of claim 1 further including, if the target regeneration of the at least one aftertreatment device has not occurred following adjustment of the boost recirculation valve associated with the inlet air supply system, then determining if the calibration of the exhaust gas recirculation system with the engine is at the maximum level.

7. The method of claim 1 wherein the at least one aftertreatment device is a selective catalytic reduction device.

8. A system for regenerating at least one aftertreatment device in an exhaust system of an internal combustion engine including an exhaust gas recirculation system, the system comprising:
at least one sensor adapted to determine and provide a signal indicative of a temperature of exhaust gas reaching the at least one aftertreatment device;
at least one of
at least one sensor associated with the at least one aftertreatment device and adapted to determine and provide a signal indicative of a level of regeneration of the aftertreatment device, and
at least one timer adapted to provide a signal indicative of a time period for which the at least one aftertreatment device has received exhaust gas at a regeneration target temperature;

an inlet air supply system including a compressor;
a boost recirculation valve associated with the inlet air supply system; and
a controller including computer-readable instructions for calibrating the exhaust gas recirculation system with the engine, the instructions including:
instructions for determining if regeneration of the at least one aftertreatment device is needed;
instructions for changing a calibration of the exhaust gas recirculation system with the engine to increase temperature of exhaust gas provided to the at least one aftertreatment device;
instructions for determining if the temperature of the exhaust gas provided to the aftertreatment device is above a regeneration target temperature based upon the signal indicative of the temperature of exhaust gas reaching the at least one aftertreatment device;
if the temperature of the exhaust gas provided to the aftertreatment device is above the regeneration target temperature, instructions for determining if a target regeneration has occurred after a regeneration period based upon the signal indicative of the level of regeneration of the aftertreatment device or the signal indicative of the time period;
if the target regeneration has occurred, then instructions for ending regeneration;
if the target regeneration has not occurred, then instructions for determining if the calibration of the exhaust gas recirculation system with the engine is at a maximum level;
if the calibration of the exhaust gas recirculation system with the engine is not at the maximum level, then instructions for incrementally changing the calibration of the exhaust gas recirculation system with the engine to increase the temperature of the exhaust gas provided to the at least one aftertreatment device until such time as the target regeneration occurred or the calibration of the exhaust gas recirculation system with the engine is at the maximum level;
if the temperature of the exhaust gas provided to the aftertreatment device is not above the regeneration target temperature, then instructions for determining if the calibration of the exhaust gas recirculation system with the engine is at the maximum level;
if the calibration of the exhaust gas recirculation system with the engine is not at the maximum level, then instructions for incrementally changing the calibration of the exhaust gas recirculation system with the engine to increase the temperature of the exhaust gas provided to the at least one aftertreatment device until such time as the temperature of the exhaust gas provided to the aftertreatment device is above the regeneration target temperature and target regeneration has occurred, or until the calibration of the exhaust gas recirculation system with the engine is at the maximum level; and
wherein the instructions further include instructions for adjusting the boost recirculation valve associated with the inlet air supply system to divert so

Assignees

• Caterpillar Inc

Inventors

• Sunley Ryan T
• Charbonnel Sylvain
• Huhn Spencer

Classifications

• F02D41/0007

  for control of turbo-charged or super-charged engines (control of the pumps per se F02B37/12) · CPC title

• Y02T10/26

  Cross-Sectional Technologies · mapped topic

• F02M26/47

  the characteristics being temperatures, pressures or flow rates · CPC title

• F01N2610/02

  the substance being ammonia or urea · CPC title

• F02M2026/004

  EGR valve controlled by a temperature signal or an air/fuel ratio (lambda) signal · CPC title