Post injection control method during exhaust brake operation

A post injection control method during exhaust brake operation of a system, wherein the system includes a vehicle operation detector that detects operation statuses of a vehicle, an exhaust brake valve that controls an exhaust gas flow of an engine, a diesel oxidation catalyst, a diesel particulate filter disposed downstream of the diesel oxidation catalyst, an injector for injecting fuel, and a controller for controlling an operation of the injector and the exhaust brake valve based on the detected operation statuses of the vehicle, the post injection control method comprising:

• determining, by the controller, whether a predetermined regeneration condition of the diesel particulate filter based on output signals corresponding to the detected operation statuses from the vehicle operation detector is satisfied;
• when the predetermined regeneration condition is satisfied, performing, by the controller, regeneration by controlling the operation of the injector;
• during the regeneration, determining, by the controller, whether an exhaust brake operation condition is satisfied based on the output signals from the vehicle operation detector;
• and
• when the exhaust brake operation condition is satisfied during the regeneration, controlling, by the controller, the operation of the injector to perform post-injection with a predetermined amount of fuel,
• wherein the predetermined amount of fuel for the post injection is determined by the controller by applying a target temperature upstream of the diesel particulate filter, an actual temperature upstream of the diesel particulate filter, and a current engine revolutions per minute (RPM) into a predetermined post injection amount control map, and
• wherein the predetermined post injection amount control map is preset based on the target temperature upstream of the diesel particulate filter, the actual temperature upstream of the diesel particulate filter, and a temperature change of the diesel oxidation catalyst according to an engine RPM during regeneration.