Method and system for controlling an electrically heated particulate filter
A method and system for controlling a diesel particulate filter includes a particulate matter load determination module determining a particulate matter load in a diesel particulate filter (DPF), a desired oxygen level determination module determining a desired exhaust gas oxygen level based on the particulate matter load, an oxygen comparison module comparing the desired exhaust gas oxygen level and a measured exhaust gas oxygen level and generating a comparison signal and an electric DPF control module controlling an electrically heated catalyst in response to the comparison signal.
1. A control system comprising:
a particulate matter load determination module determining a particulate matter load in a diesel particulate filter;
a desired oxygen level determination module determining a desired exhaust gas oxygen level based on the particulate matter load;
an oxygen comparison module comparing the desired exhaust gas oxygen level and a measured exhaust gas oxygen level and generating a comparison signal; and
an electric DPF control module controlling an electrically heated catalyst in response to the comparison signal.
2. A control system as recited in claim 1 wherein the electrically heated catalyst comprises an electrically heated diesel particulate filter.
3. A control system as recited in claim 1 wherein the desired oxygen level determination module determines the desired exhaust gas oxygen level based on the particulate matter load and a maximum desired catalyst temperature.
4. A control system as recited in claim 3 wherein the maximum desired temperature corresponds to a lowest diesel particulate filter temperature for removing soot from the diesel particulate filter.
5. A control system as recited in claim 3 wherein the maximum desired temperature corresponds to a lowest diesel particulate filter temperature for removing soot from the diesel particulate filter a predetermined axial direction into the diesel particulate filter.
6. A control system as recited in claim 1 further comprising an engine control module controlling the exhaust gas oxygen level.
7. A control system as recited in claim 6 wherein the engine control module controls the exhaust gas oxygen level by controlling at least one of air fuel ratio, exhaust gas recirculation and a post exhaust injector.
8. A control system as recited in claim 6 wherein the engine control module controls the exhaust gas oxygen level by controlling at least two of air fuel ratio, exhaust gas recirculation and a post exhaust injector.
9. A control system as recited in claim 1 further comprising a diesel engine.
10. A control system as recited in claim 9 wherein the diesel engine generates an exhaust stream and further comprising an oxygen sensor sensing the exhaust oxygen level.
11. A method comprising:
determining a particulate matter load in a diesel particulate filter;
determining a desired exhaust gas oxygen level based on the particulate matter load;
measuring an exhaust gas oxygen level to form a measured exhaust gas oxygen level;
comparing the desired exhaust gas oxygen level and the measured exhaust gas oxygen level; and
controlling an electrically heated catalyst in response to comparing.
12. A method as recited in claim 11 further comprising controlling the exhaust gas oxygen level.
13. A method as recited in claim 11 wherein controlling an electrically heated catalyst comprises electrically heating the diesel particulate filter.
14. A method as recited in claim 11 wherein determining a particulate matter load in a diesel particulate filter comprises determining the particulate matter load in the diesel particulate filter in an exhaust stream of a diesel engine.
15. A method as recited in claim 11 wherein determining a desired exhaust oxygen level comprises determining the desired exhaust gas oxygen level based on the particulate matter load and a maximum desired catalyst temperature.
16. A method as recited in claim 15 wherein the maximum desired temperature corresponds to a lowest diesel particulate filter temperature for removing soot from the diesel particulate filter.
17. A method as recited in claim 15 wherein the maximum desired temperature corresponds to a lowest diesel particulate filter temperature for removing soot from the diesel particulate filter a predetermined axial direction into the diesel particulate filter.
18. A method as recited in claim 12 wherein controlling the exhaust gas oxygen level comprises controlling at least one of air fuel ratio, exhaust gas recirculation and a post exhaust injector.
19. A method as recited in claim 18 wherein controlling the post exhaust injector comprises injecting urea through an injector.
20. A method as recited in claim 12 wherein controlling the exhaust gas oxygen level comprises controlling at least two of air fuel ratio, exhaust gas recirculation and a post exhaust injector.