Engine with emissions control arrangement and method of controlling engine emissions

1. An engine with an emissions control arrangement, comprising:

an engine comprising an intake and an exhaust system;

an EGR system comprising a conduit between the exhaust system and the intake and an EGR controller adapted to control EGR flow from the exhaust system to the intake;

a reduction agent introduction system adapted to introduce a reduction agent into the exhaust system;

a controller programmed to adjust the EGR flow in a non-zero amount while also simultaneously adjusting the reduction agent introduction in a non-zero a as a function of the EGR flow to prevent NOx emissions from exceeding a predetermined maximum value while the engine is operating; and

a compressor arranged to introduce compressed charge air to the intake, wherein the controller is arranged to adjust charge air introduction as a function of the EGR flow and the reduction agent introduction.

2. The engine with an emissions control arrangement as set forth in claim 1 , comprising a sensor arranged to sense at least one operational parameter and to send a signal corresponding to the at least one sensed operational parameter to the controller, the controller being arranged to adjust the EGR flow and the reduction agent introduction as a function of the at least one sensed operational parameter.

3. The engine with an emissions control arrangement as set forth in claim 2 , wherein the at least one operational parameter comprises at least one of ambient temperature, ambient pressure, and exhaust temperature.

4. The engine with an emissions control arrangement as set forth in claim 1 , wherein the controller is arranged to adjust the charge air introduction, the EGR flow, and the reduction agent introduction to prevent NOx emissions from exceeding a predetermined maximum value.

5. The engine with an emissions control arrangement as set forth in claim 1 , wherein the compressor is a component of a turbocharger.

6. The engine with an emissions control arrangement as set forth in claim 5 , wherein the compressor is part of a variable geometry turbocharger.

7. The engine with an emissions control arrangement as set forth in claim 1 , comprising a fuel injector arranged to inject fuel into the engine, the controller being arranged to adjust timing of fuel injection as a function of the EGR flow and the reduction agent introduction.

8. The engine with an emissions control arrangement as set forth in claim 7 , wherein the controller is arranged to adjust the fuel injection timing, the EGR, flow, and the reduction agent introduction to prevent NOx emissions from exceeding a predetermined maximum value.

9. A method of controlling engine emissions, comprising:

adjusting EGR. flow from an exhaust system to an intake of an engine;

adjusting introduction of a reduction agent into the exhaust system, the EGR flow being adjusted in a non-zero amount while also simultaneously adjusting reduction agent introduction non-zerc amount as a function of the EGR flow so that NOx emissions are prevented from exceeding a predetermined maximum value while the engine is operating; and

adjusting charge air introduction as a function of the EGR flow and the reduction agent introduction.

10. The method of controlling engine emissions as set forth in claim 9 , comprising adjusting timing of fuel injection as a function of the EGR flow, the reduction agent introduction, and the charge air introduction.

11. The method of controlling engine emissions as sot forth in claim 10 , comprising sensing at least one operational parameter and adjusting the EGR flow, the reduction agent introduction, the charge air introduction, and the fuel injection timing as a function of the at least e sensed operational parameter.

12. The method of controlling engine emissions as set forth in claim 9 , comprising sensing at least one operational parameter and adjusting the EGR flow, the reduction agent introduction, and the charge air introduction as a function of the at least one sensed operational parameter.

13. The method of controlling engine emissions as set forth in claim 9 , comprising adjusting timing of fuel injection as a function of the EGR flow and the reduction agent introduction.

14. The method of controlling engine emissions as set forth in claim 9 , comprising sensing at least one operational parameter and adjusting the EGR flow and the reduction agent introduction as a function of the at least one sensed operational parameter.

15. The method of controlling engine emissions as set forth in claim 9 , comprising decreasing the EGR flow as a function of increasing ambient temperature.

16. The method of controlling engine emissions as set forth in claim 9 , comprising decreasing the EGR flow as a function of increasing exhaust temperature.

17. The method of controlling engine emissions as set forth in claim 9 , comprising decreasing the EGR flow as a function of decreasing ambient pressure.

18. The method of controlling engine emissions as set forth in claim 9 , wherein the EGR flow and the reduction agent introduction are inversely related.

19. The engine with an emissions control arrangement as set forth in claim 1 , comprising a selective catalytic reduction catalyst downstream of the reduction agent introduction system.

20. The engine with an emissions control arrangement as set forth in claim 16 , comprising a source of urea or an ammonia-based substance, the reduction agent introduction system being connected to the source of urea or the ammonia-based substance for introducing urea or the ammonia-based substance into the exhaust system.

21. The engine with an emissions control arrangement as set forth in claim 1 , comprising a source of urea or an ammonia-based substance, the reduction agent introduction system being connected to the source of urea or the ammonia-based substance for introducing urea or the ammonia-based substance into the exhaust system.

22. The method of controlling engine emissions as set forth in claim 9 , wherein the reduction agent is introduced into the exhaust system upstream from a selective catalytic reduction catalyst.

23. The method of controlling engine emissions as set forth in claim 22 , comprising introducing urea or an ammonia-based substance into the exhaust system as the reduction agent.

24. The method of controlling engine emissions as set forth in claim 9 , comprising introducing urea or an ammonia-based substance into the exhaust system as the reduction agent.