Update on Ammonia Engine Combustion Using Direct Fuel Injection

Transcription

1 Update on Ammonia Engine Combustion Using Direct Fuel Injection Christopher Gross, George Zacharakis-Jutz Song-Charng Kong Department of Mechanical Engineering Iowa State University Acknowledgements: Iowa Energy Center; Norm Olson Robert Bosch; National Instruments 1

2 Thermodynamics/Chemistry Stoichiometric chemical reaction NH +.7 ( O N ) 1. H O N Fuel Molecule Boiling Point ( C) (Air/Fuel) s Latent Heat (kj/kg) Energy Content (MJ/kg-fuel) Energy Content (MJ/kgstoichiometric mixture) Methanol CH 3 OH Ethanol C 2 H OH Gasoline C 7 H Diesel C 14.4 H Ammonia NH

3 CI engine operation Approaches Port induction of gaseous ammonia, ignited by directly injected diesel/biodiesel fuel Achieved a wide range of load and speed conditions Direct injection of liquid ammonia/dme mixtures To be presented SI engine operation Direct injection of gaseous ammonia, enhanced by gasoline combustion On-going (to be presented) 3

4 NH 3 /DME Use direct liquid fuel injection Confine combustion mixture near the center To reduce exhaust ammonia emissions Dimethyl ether (CH 3 -O-CH 3 ) as ignition source Fuel mixing and storage at high pressure New fuel injection system without fuel return Injection pump, injector, electronic control Various NH 3 /DME ratios Fuel injector 4

5 Engine Setup Yanmar diesel engine (L7V, 32 c.c.) Rated power at 6.26 hp at 3,48 rpm Developed new fuel injection and engine control systems Bosch GDI type injector (up to 2 bar injection pressure)

6 Setup Mixing and storage of ammonia/dme at high pressure Exhaust emissions measurements Horiba MEXA-71DEGR (CO 2, CO, O 2, HC) Horiba 117NX (NO x, NH 3 ) Emissions analyzers AVL Smoke Meter (PM) Fuel mixing system

7 Operating Range Challenges Latent heat Flame speed Low to medium loads at various speeds Power [HP] Maximum Power Output utilizing different Fuels Diesel (baseline) 1% DME 2%NH3-8%DME 4%NH3-6%DME Heat of Vaporization Diesel Fuel 2 Flame Speed Engine Speed [RPM]

8 Test Conditions Mode Engine Speed (rpm) Engine Power (kw) Engine Torque (Nm) Fuel SOI (btdc) P_inj T_intake air 1%DME ~ 3 1 bar 3 C 2%NH 3-8%DME ~ 3 1 bar 6 C 4%NH 3-6%DME 1 ~ 4 18 bar 8 C 6%NH 3-4%DME 14 ~ 18 2 bar 9 C Results will be presented first

9 Sample Results (P & HRR) Cylinder Pressure (bar) SOI = 2 BTDC 1%DME 2%NH3-8%DME 4%NH3-6%DME HRR (J/deg) Cylinder Pressure (bar) SOI = 1 BTDC 1%DME 2%NH3-8%DME 4%NH3-6%DME HRR (J/deg) Crank Angle (deg) Crank Angle (deg) Cylinder Pressure (bar) SOI = 2 BTDC 1%DME 2%NH3-8%DME 4%NH3-6%DME HRR (J/deg) Crank Angle (deg)

10 Results Observation on combustion No significant deterioration of combustion More ammonia longer ignition delays, more significant premixed combustion Reporting emissions Reported in BSEC [MJ/kWh] (instead of BSFC [g/kwh]) Imply the fuel energy consumption rate, fuel economy As 3,2 rpm and 4.3kW running on diesel fuel BSEC is MJ/kWh, corresponding to a BSFC of 34.8 g/kwh for the current engine.

11 NOx Emissions NOx (g/kwh) Mode 11 Mode 2 Mode 21 Single Injection, 1% DME NOx (g/kwh) Mode 11 Mode 2 Mode 21 Single Injection, 2%NH3-8%DME BSEC (MJ/kWh) NOx (g/kwh) Mode 3 Mode 11 Mode 2 Mode BSEC (MJ/kWh) BSEC (MJ/kWh) Single Injection, 4%NH3-6%DME Reference data using diesel fuel

12 NH 3 Emissions NH3 (g/kwh) Mode 11 Mode 2 Mode 21 Single Injection, 2%NH3-8%DME BSEC (MJ/kWh) NH3 (g/kwh) Mode 3 Mode 11 Mode 2 Mode 21 Single Injection, 4%NH3-6%DME BSEC (MJ/kWh)

13 NH 3 Emissions NH3 (ppm) Mode 11 Mode 2 Mode 21 2%NH3-8%DME BSEC (MJ/kWh) NH3 (ppm) Mode 3 Mode 11 Mode 2 Mode 21 4%NH3-6%DME BSEC (MJ/kWh)

14 Soot Emissions Soot (g/kwh) Mode 11 Mode 2 Mode 21 Single Injection, 1% DME Soot (g/kwh) Mode 11 Mode 2 Mode 21 Single Injection, 2%NH3-8%DME BSEC (MJ/kWh) Extremely low soot emissions HC and CO levels comparable among different fuel mixtures Soot (g/kwh) BSEC (MJ/kWh) Mode 3 Mode 11 Mode 2 Mode 21 Single Injection, 4%NH3-6%DME BSEC (MJ/kWh)

15 6%NH 3-4%DME Injection pressure positive effects on combustion To enable combustion of 6%NH 3-4%DME P_inj=2 bar, SOI= 18 btdc, T_intake= 9 C Achieved higher load and speed operation 2 rpm & 3.6 hp.

16 NOx and NH 3 Emissions NOx [g/kwh] 6%NH3-4%DME 4 6NH3_19_18_1 6NH3_19_18_2 4 6NH3_2_18_ Start of injection [ o CA BTDC] NH 3 [g/kwh] %NH3-4%DME 6NH3_19_18_1 6NH3_19_18_2 6NH3_2_18_ Start of injection [ o CA BTDC] Higher load benefits NH 3 combustion; More stable operation; Flexibility in injection timing.

17 Current test engine Perspectives Small size, high heat loss, operated at high speed, low injection pressure Application to larger diesel engine Operated at lower speed, high injection pressure Exhaust after-treatment (SCR system without urea injection) Fuel cost based on $3.7/gal diesel, $/ton ammonia, $7/ton DME Diesel fuel 4%ammonia/ 6% diesel 4%ammonia/ 6% DME BSEC (MJ/kWh) LHV (MJ/kg) Ammonia Fuel rate (kg/kwh) Fuel price ($/kg) $1.18 $.9 $.74 $.6 Fuel energy cost $.29 $.3 $.3 $.34 ($/kwh)

18 DISI NH 3 Engine Direct injection of gaseous ammonia Maximize volumetric efficiency, thus maximizing air fuel charge Prevent negative effects of high latent heat of ammonia Solenoid driven pulse valve Withstands corrosive effects of ammonia Designed for gaseous applications Cheap and readily accessible Solenoid Valve Pressure Transducer

19 Gaseous NH 3 Injection Fuel pump and storage operate on liquid basis Injection line pressure approx. 3 bar Injection line heated to achieve gaseous fuel Temperature required 6 C Heat provided by heat tape Expansion chamber to compensate for dramatic volumetric change upon vaporization Pressure Reducing Regulator Pressure release Valve Surge Tank Pump Ammonia Bottle Pressurization Tank Fuel Scale

20 Progress Update Fuel storage, heating, injection systems completed. Initial engine tests conducted Engine operates on gasoline Engine torque increases when ammonia injection is activated Detailed measurements in progress

21 CI engines using ammonia Summary Port induction of vapor ammonia + DI diesel fuel DI ammonia/dme mixtures Large engine will favor operation using ammonia After-treatment using SCR for NOx and ammonia reduction DISI ammonia engine Injection system implemented Detailed measurements in progress 21