Low emission diesel particulate filter (DPF) regeneration

1. A method of operating a diesel engine, comprising:

dividing exhaust gas generated by said diesel engine into first and second exhaust segments that respectively channel exhaust gas from first and second cylinder banks;

redirecting at least a portion of said first exhaust segment into cylinders of said diesel engine and inhibiting re-circulation of exhaust from said second exhaust segment during a first mode;

redirecting a portion of exhaust from each of said first and second exhaust segments back into said diesel engine during a second mode;

injecting fuel into said second exhaust segment during a first mode;

directing said second exhaust segment and a remainder of said first exhaust segment to a particulate filter during said first mode; and

combusting said fuel to burn particulates trapped within a particulate filter.

2. The method of claim 1 further comprising cooling said portion of said first exhaust segment.

3. The method of claim 1 further comprising driving a turbo unit using said second exhaust segment and said remainder of said first exhaust segment.

4. The method of claim 1 further comprising initiating combustion of said fuel using a catalyst.

5. The method of claim 1 further comprising calculating an engine load, wherein a volume of said portion of said first exhaust segment is determined based on said engine load.

6. The method of claim 5 further comprising detecting a fueling rate, wherein said engine load is based on said fueling rate.

7. The method of claim 5 further comprising detecting an engine speed, wherein said engine load is based on said engine speed.

8. A method of operating a diesel engine, comprising:

calculating an exhaust re-circulation value;

redirecting at least a portion of a first exhaust segment generated by said diesel engine into cylinders of said diesel engine to achieve said exhaust re-circulation value and inhibiting re-circulation of said second exhaust segment when said exhaust re-circulation value is below a threshold value during a first mode;

redirecting a portion of each of said first and second exhaust segments back into said diesel engine during a second mode;

injecting fuel into a second exhaust segment generated by said diesel engine when said exhaust re-circulation value is below said threshold value during said first mode;

directing said second exhaust segment and a remainder of said first exhaust segment to a particulate filter during said first mode; and

combusting said fuel to burn particulates trapped within a particulate filter.

9. The method of claim 8 wherein said threshold value is equal to 50% of a total amount of exhaust generated by said diesel engine.

10. The method of claim 8 further comprising prohibiting said step of injecting fuel when said exhaust re-circulation value is above said threshold value.

11. The method of claim 8 further comprising cooling said portion of said first exhaust segment.

12. The method of claim 8 further comprising driving a turbo unit using said second exhaust segment and said remainder of said first exhaust segment.

13. The method of claim 8 further comprising initiating combustion of said fuel using a catalyst.

14. The method of claim 8 further comprising calculating an engine load, wherein said exhaust re-circulation value is determined based on said engine load.

15. The method of claim 14 further comprising detecting a fueling rate, wherein said engine load is based on said fueling rate.

16. The method of claim 14 further comprising detecting an engine speed, wherein said engine load is based on said engine speed.

17. A diesel engine system, comprising:

a diesel engine having a first exhaust segment that channels exhaust gas from a first cylinder bank and a second exhaust segment that channels exhaust gas from a second cylinder bank;

a filter that filters exhaust gas from said first and second exhaust segments;

a flow control valve that selectively re-circulates a portion of exhaust from said first exhaust segment back into said diesel engine and inhibits re-circulation of exhaust from said second exhaust segment during a first mode and that re-circulates a portion of exhaust from each of said first and second exhaust segments back into said diesel engine during a second mode; and

an injector system that injects fuel into exhaust flowing through said second exhaust segment during said first mode, wherein said fuel is combusted to regenerate said filter.

18. The diesel engine system of claim 17 further comprising a catalyst that promotes combustion of said fuel.

19. The diesel engine system of claim 17 further comprising a turbo that is driven by said exhaust and that compresses air for combustion in said diesel engine.

20. The diesel engine system of claim 17 further comprising a cooler that cools said re-circulated portion of said exhaust.

21. The diesel engine system of claim 17 wherein said flow control valve is controlled based on an engine load.

22. The diesel engine system of claim 21 further comprising an engine speed sensor that generates an engine speed signal, wherein said engine load is determined based on said engine speed signal.

23. The diesel engine system of claim 21 wherein said engine load is based on a fueling rate of said diesel engine.