Session 34 Per Stålhammar


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Session 34 Per Stålhammar

  1. 1. Dual-fuel-tekniken– hur fungerar den och vad har den att ge?Per Stålhammar
  2. 2. What is AVL? AVL Powertrain Engineering n ts me passenger cars 2-wheelers racing eg rS AVL me Advanced sto Engineering Simulation cu Technologies al l construction agriculture commercial vehicle e rs c ov AVL Testing AVL Instrumentation and Test Systems locomotive marine power plants 2
  3. 3. What is AVL Sweden? MTC - Founded 1988 Independent Company 1998 In the AVL-group 2002 Acquired GMPT Södertälje 2008 Situated in Haninge, Södertälje and Gothenburg Center Of Expertice for alternative fuels Notified Technical Service Accreditations Japan TRIAS (2000) ISO 17025 (2001) ISO 9001 2000 (2001) ~ 200 Persons Employed 3
  4. 4. Methane Engine Technologies Different Technologies for different applications SI (Spark Ignited) CI (Compression Ignited) Stoichiometric Lean Burn Bi-fuel Dedicated gas (mono-fuel) 4
  5. 5. Why Dual Fuel?Possible to convert Diesel engine to Duel Fuelwithout major changes to base engine.Possible to continue running on Diesel if gas isnot available.Higher efficiency compared to spark ignited gasengines.Possible to convert the engine back to originalDieselNo spark plugs
  6. 6. Dual Fuel - Diesel or Otto combustion?Diesel OttoNo throttle Throttle to control A/FCompression ignited Spark ignitedHigh compression ratio Knock limited compression ratioDiffusion controlled Flame propagating controlledcombustion combustion Dual Fuel (except DI gas) Throttle to control A/F Compression ignited Knock limited compression ratio Flame propagating controlled 6
  7. 7. Dual Fuel converted Diesel engine(Typical retrofit solution) Throttle Gas supply 7
  8. 8. Dual Fuel converted Diesel engine(Typical OEM solution for large engines)Inlet manifold: Turbocharger:Throttle - Compressor Bypass /Gas piping Waste-Gate / VTGCylinder head: - Re-specify- Cylinder-individual gas admission valves Piston:- Pilot fuel injectors - Reduced- Increased turbulence compression ratio- Valve seat material - Bore increaseCR Pilot Diesel Injection: Liner:- Electrically-driven HP Bore increasePumps- Piping Camshaft: Int. & exh. cam profileCrank case:- Safety relief valves for Engine Control System: intake receiver - Gas operation- Crankcase ventilation - Knock control with gas detection - Wiring sensor 8
  9. 9. Technical challenges with Dual FuelCombustion chamber is not optimized for Ottocombustion leading to high levels of Methane slip Throttle is needed, leading to decreased efficiency atpart load. (increased pumping losses)Not possible/suitable to run gas at idle and low loadsNot possible to run gas at full load (knock limitations) 9
  10. 10. Damages from knocking combustionin a retrofit Dual Fuel engine Before knocking After 10
  11. 11. Dual Fuel Technologies Premixed gas system DI gas system (Micro pilot ignition) Picture Wärtsilä 11
  12. 12. Dual Fuel Technologies Premixed gas with DI gas with diesel ignition diesel ignitionGenerally higher levels of HC Generally higher NOx than premixed(Methane) from crevices and flame depending on diffusion controlledquenching. combustion.Knock limited performance on gas. Better knock tolerance than premixedPossible to run 100% Diesel mode Less HC from creviceswhen gas is not available. Limited performance on DieselDemand throttle which leads to poor Generally more expensive thanpart load efficiency Premixed systemsMore system suppliers than DI 12
  13. 13. Dual Fuel Technologies AVL pre-chamber system for large engines-ultra lean burn 13
  14. 14. Aftertreatment systems for Dual FuelChallanges High levels of unburnt methane Low exhaust temperature Cold start demands from EURO VIAfter treatment system Methane oxidation catalyst with high efficiency and durability is needed from EURO III SCR or DPF/POC is probably needed for EURO VI (maybe also for EURO V) 14
  15. 15. Dual Fuel CombustionDual fuel combustion propertiesfrom R&D project in Sweden Later pilot injection Earlier pilot injection 15
  16. 16. Dual Fuel system suppliersExamples of Duel Fuel System Suppliers Bosch Clean Air Power Hardstaff Westport 16
  17. 17. Dual Fuel system suppliers Clean Air Power Secondary intercooler to enable higher power without knock Picture CAP
  18. 18. Dual Fuel system suppliersHardstaff OIGI Dual Fuel Technology (Oil Ignition Gas Injection) 2 injectors per cylinder –reduced duty cycle Injector layout to achievesequential operation Point of injection close to eachinlet valve Picture Hardstaff
  19. 19. Dual Fuel system suppliersHardstaff Dual Fuel Technology (aftertreatment ) Picture Hardstaff
  20. 20. Dual Fuel system suppliersWestport HPDI Dual fuel system (High Pressure Direct gas Injection) Picture Westport
  21. 21. Dual Fuel system suppliersWestport HPDI Dual fuel system Picture Hardstaff
  22. 22. Dual Fuel TechnologiesConclusions Dual Fuel combustion is more complex than conventional. Dual Fuel enables new combustion strategies Dual Fuel has not yet shown its full potential in truck applications Lack of legislation hamper further 22