NOx Emissions Reduction of a Natural Gas SI Engine under Lean Conditions: Comparison of the EGR and RGR Concepts

1. N Ox Emissions Reduction of a Natural Gas SI Engine under Lean Conditions: Comparison of the EGR and RGR concepts Olivier LE CORRE Frédéric PIROTAIS E.M.N. - FRANCE I.N.P.G. - FRANCE Spring Technical Conference, May 8 – 10, 2006, Aachen, Germany

2. INTRODUCTION CHP fuelled by NG - good thermal efficiency - smaller impact on global warning high H/C ratio limits CO2 emission Nevertheless - high emission level of UHC Sogaard et al. Main advantages of a hydrocarbon and hydrogen blend - increases thermal efficiency - reduces UHC, CO, CO2 emissions Tsolakis et Megaritis Nevertheless - NOx emissions raising Spring Technical Conference, May 8 – 10, 2006, Aachen, Germany

3. INTRODUCTION Hydrogen: fuel for the future? Unfortunately Hydrogen production and storage are difficult Hoekstra Idea : in-situ fuels reforming Zheng et al. Spring Technical Conference, May 8 – 10, 2006, Aachen, Germany

4. RGR Concept Spring Technical Conference, May 8 – 10, 2006, Aachen, Germany

5. Table of contents 1/ SI engine Thermodynamic model Test bench 2/ Reformer Model Bibliography 3/ Feedback loop 4/ Conclusion and perspectives Spring Technical Conference, May 8 – 10, 2006, Aachen, Germany

6. Table of contents 1/ SI engine Thermodynamic model Test bench 2/ Reformer Model Bibliography 3/ Feedback loop 4/ Conclusion and perspectives Spring Technical Conference, May 8 – 10, 2006, Aachen, Germany

7. Two-zone thermodynamic model - fresh and burnt gases - an uniform in-cylinder pressure - both leakage and blow-by are neglected - burnt mass fraction, see Chelma - laminar speed of blend, see Shahad Al-Janabi and Sadi Al-Baghadi - wall heat transfer, see Hohenberg Spring Technical Conference, May 8 – 10, 2006, Aachen, Germany

8. Test Bench Spring Technical Conference, May 8 – 10, 2006, Aachen, Germany

9. Spring Technical Conference, May 8 – 10, 2006, Aachen, Germany

10. S.I. engine Good agreements between numeric simulations and experimental tests Spring Technical Conference, May 8 – 10, 2006, Aachen, Germany

11. Table of contents 1/ SI engine Thermodynamic model Test bench 2/ Reformer Model Bibliography 3/ Feedback loop 4/ Conclusion and perspectives Spring Technical Conference, May 8 – 10, 2006, Aachen, Germany

12. Reformer : model at equilibrium See Xu and Froment Spring Technical Conference, May 8 – 10, 2006, Aachen, Germany

13. Reformer : plug flow Spring Technical Conference, May 8 – 10, 2006, Aachen, Germany

14. Reformer results comparison with bibliography Allenby Spring Technical Conference, May 8 – 10, 2006, Aachen, Germany

15. Table of contents 1/ SI engine Thermodynamic model Test bench 2/ Reformer Model Bibliography 3/ Feedback loop 4/ Conclusion and perspectives Spring Technical Conference, May 8 – 10, 2006, Aachen, Germany

16. Feedback loop Spring Technical Conference, May 8 – 10, 2006, Aachen, Germany

17. Table of contents 1/ SI engine Thermodynamic model Test bench 2/ Reformer Model Bibliography 3/ Feedback loop 4/ Conclusion and perspectives Spring Technical Conference, May 8 – 10, 2006, Aachen, Germany

18. Conclusion and Perspectives Blend of Reformed Gas Recirculation and Natural Gas : an opportunity to optimise the CHP engines Nevertheless, under very lean conditions, misfire occures and leads cycle to cycle dispersions. On one hand, hydrogen improves flame propagation BUT, on the other hand very lean conditions reduce it. Spring Technical Conference, May 8 – 10, 2006, Aachen, Germany