Dual Fuel Combustion an Applicable Technology for Mobile Application?

Transcription

1 1 S C I E N C E P A S S I O N T E C H N O L O G Y Dual Fuel Combustion an Applicable Technology for Mobile Application? 10 th Conference Eco Mobility 2025plus Univ.Prof. Dr. Helmut Eichlseder Institute of Internal Combustion Engines and Thermodynamics Graz University of Technology

2 Experimental Investigation of CNG-Diesel Combustion Processes 2 Dual Fuel Definition and Possibilities Dual Fuel Compression Ignition Combustion Concept for Gasoline and Diesel Hepp et al. SAE Paper Dual Fuel Hydrogen/Gasoline Concept for Aston Martin Hepp et al. A3PS Conference 2013

3 Experimental Investigation of CNG-Diesel Combustion Processes 3 Dual Fuel Definition and Possibilities H 2 /Diesel Dual-Fuel Engine for Use in Public Transport Barnstedt et al. Gasfahrzeugtagung 2015 Natural Gas/Diesel Dual Fuel System Principle

4 Experimental Investigation of CNG-Diesel Combustion Processes 4 CNG-Diesel A new combustion concept? Ship engines Large engines Truck engines? Passenger cars?

5 5 Experimental Investigation of CNG-Diesel Combustion Processes CNG-Diesel Motivation Reduction of CO 2 -Emissions Economy - Reduced Fuel Costs Improvement of Soot/NO x -trade off Improved knocking behaviour Proven technology

6 6 Experimental Investigation of CNG-Diesel Combustion Processes CNG-Diesel Motivation Diesel CNG-Diesel Dual-Fuel combustion process Diesel Natural Gas CO 2 reduction potential compared to diesel operation CNG-Diesel Micro-Pilot combustion process Natural Gas CO 2 -Emissions / % x m H m H at 50% substitution -12.5% at 90% substitution -23% Substituted energy content x CNG / %

7 7 Results presented at A3PS 2012 n=2000/pe=6 bar High potential from medium-load upward; CH 4 emission! Operation above CH = 2 not meaningful 4 Content of CH 4 at low-load range limited ( e ) Possible fields of application of this combustion process Light-/Heavy Duty: long-distance traffic with LNG Off-road sector: construction machines, tractors e.g. Biogas Eichlseder H., Grabner P. Vienna, Dec. 11, 2012

8 8 Experimental Investigation of CNG-Diesel Combustion Processes Passenger Car - Operation conditions Full load diesel BMEP / bar High load operating point n=1750min -1 / BMEP=15bar Low load operating point n=1500min -1 / BMEP=3bar Operating points NEDC Examined load points n / min -1

9 Experimental Investigation of CNG-Diesel Combustion Processes 9 Experimental results at low load operation with external mixture formation n=1500min -1 / BMEP=3bar Diesel (reference) CNG-Diesel with external mixture formation, x CNG =50% Unburned constituents IC / % Engine efficiency e / % CO 2 Emissions / g/kwh Quelle: Sprenger, Fasching, Kammerstätter; Arbeitsprozeßtagung Graz, 2015

10 10 Experimental Investigation of CNG-Diesel Combustion Processes Experimental results at low load operation with external mixture formation Air fuel equivalence ratio / Intake upper flammable limit UFL lower flammable limit LFL (x) *(x) Distance x Aim: Combustion process within the ignition limits Reduction of the intake manifold pressure (throttling) Exhaust gas recirculation (EGR) Quelle: Sprenger, Fasching, Kammerstätter; Arbeitsprozeßtagung Graz, 2015

11 Experimental Investigation of CNG-Diesel Combustion Processes 11 CNG-Diesel Concept CNG-Diesel External mixture formation CNG-Diesel Internal mixture formation

12 12 Experimental Investigation of CNG-Diesel Combustion Processes Experimental setups and operating conditions DIESEL (Reference) Engine type B47C20O0 Displacement 1995 cm³ Bore 84 mm Stroke 90 mm Compression ratio 16.5 CNG-Diesel External Mixture Formation Engine type Injector Quantity Rail pressure gas Layout B47C20O0 BOSCH NGI2 2 per Cylinder 8 bar Intake manifold CNG-Diesel Internal Mixture Formation Engine type Injector Quantity Rail pressure gas Layout B47C20O0 DELPHI CNG 1 per Cylinder 16 bar Cylinder head Diesel injector Quelle: Sprenger, Fasching, Kammerstätter; Arbeitsprozeßtagung Graz, 2015

13 13 Experimental Investigation of CNG-Diesel Combustion Processes Numerical flow simulation at low load operation External Mixture Formation Parameter Value BMEP / bar 3 n/ min EGR / % 0 Piston shape Omega Displayed / CA BTDC 10 Internal Mixture Formation λ/ Injector BOSCH NGI2 Injector DELPHI CNG Position Rail pressure gas Start of injection Tangential port 8 bar 340 CA BTDC Position Rail pressure gas Start of injection Central 16 bar 80 CA BTDC Homogeneous mixture Stratified mixture Quelle: Sprenger, Fasching, Kammerstätter; Arbeitsprozeßtagung Graz, 2015

14 Experimental Investigation of CNG-Diesel Combustion Processes 14 Comparison between external and internal mixture formation at low load operation n=1500min -1 / BMEP=3bar Diesel (reference) CNG-Diesel with external mixture formation, x CNG =50% CNG-Diesel with internal mixture formation, x CNG =80% Unburned constituents IC / % Engine efficiency e / % CO 2 Emissions / g/kwh Quelle: Sprenger, Fasching, Kammerstätter; Arbeitsprozeßtagung Graz, 2015

15 Experimental Investigation of CNG-Diesel Combustion Processes 15 Summary With external mixture preparation PC required functionality (CH 4 emission!) not achievable Transition from homogeneous to stratified charge at low load operation required) Reduction of the HC-emissions by more than 60% feasible Increased efficiency CO 2 reduction potential from combustion also at low load operation, but: With todays exhaust aftertreatment future emission limits not achievable (Light off temperature for CH 4 conversion)

16 Experimental Investigation of CNG-Diesel Combustion Processes 16 Outlook Further development of CNG-Diesel Micro-Pilot combustion process with internal mixture formation Optimisation of application and hardware parameters Operating strategy Full load operation (knocking behaviour) Exhaust gas aftertreatment progress? Comparison to conventional spark ignition