update on ammonia engine combustion using direct fuel ......• fuel mixing and storage at high...

Department of Mechanical Engineering, Iowa State University 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

Department of Mechanical Engineering, Iowa State University 2

Thermodynamics/Chemistry

• Stoichiometric chemical reaction

3 2 2 2 20.75 ( 3.76 ) 1.5 3.32NH O N H O N+ ⋅ + ⋅ → ⋅ + ⋅

Fuel Molecule Boiling Point (°C) (Air/Fuel)s

Latent Heat

(kJ/kg)

Energy Content

(MJ/kg-fuel)

Energy Content (MJ/kg-

stoichiometric mixture)

Methanol CH3OH 64.7 6.435 1203 20 2.6900

Ethanol C2H5OH 78.4 8.953 850 26.9 2.7027

Gasoline C7H17 --- 15.291 310 44 2.5781

Diesel C14.4H24.9 --- 14.3217 230 42.38 2.7660

Ammonia NH3 –33.5 6.0456 1371 18.6103 2.6414

Department of Mechanical Engineering, Iowa State University 3

Approaches

• CI engine operation • 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)

Department of Mechanical Engineering, Iowa State University

NH3/DME

• Use direct liquid fuel injection • Confine combustion mixture near the center • To reduce exhaust ammonia emissions

• Dimethyl ether (CH3-O-CH3) as ignition source • Fuel mixing and storage at high pressure • New fuel injection system – without fuel return

• Injection pump, injector, electronic control

• Various NH3/DME ratios

4

Fuel injector

Department of Mechanical Engineering, Iowa State University

Engine Setup

• Yanmar diesel engine (L70V, 320 c.c.) • Rated power at 6.26 hp at 3,480 rpm

• Developed new fuel injection and engine control systems • Bosch GDI type injector (up to 200 bar injection pressure)

Department of Mechanical Engineering, Iowa State University

Setup • Mixing and storage of ammonia/DME at high pressure • Exhaust emissions measurements

• Horiba MEXA-7100DEGR (CO2, CO, O2, HC) • Horiba 1170NX (NOx, NH3) • AVL Smoke Meter (PM)

Fuel mixing system

Emissions analyzers

Department of Mechanical Engineering, Iowa State University

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2200 2400 2600 2800 3000 3200 3400 3600

Pow

er [H

P]

Engine Speed [RPM]

Maximum Power Output utilizing different Fuels

Diesel (baseline)

100% DME

20%NH3-80%DME

40%NH3-60%DME

• Challenges • Latent heat • Flame speed

• Low to medium loads at various speeds

Hea

t of

Vapo

riza

tion

Flame Speed

Diesel Fuel

Operating Range

Department of Mechanical Engineering, Iowa State University

Mode Engine Speed (rpm) Engine Power (kW) Engine Torque (Nm) 5 2548 1.74 6.61

7 2548 0.87 3.31

9 2895 1.05 3.52

11 3243 1.12 3.34

20 2200 1.47 6.47

21 2200 0.74 3.24

Test Conditions

Fuel SOI (btdc) P_inj T_intake air 100%DME 0 ~ 30 150 bar 30 C 20%NH3-80%DME 5 ~ 35 150 bar 60 C 40%NH3-60%DME 15 ~ 40 180 bar 80 C 60%NH3-40%DME 140 ~ 180 205 bar 90 C

Results will be presented first

Department of Mechanical Engineering, Iowa State University

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5

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15

20

25

-10

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-75 -60 -45 -30 -15 0 15 30 45 60 75

HR

R (J

/deg

)

Cyl

inde

r Pre

ssur

e (b

ar)

Crank Angle (deg)

100%DME20%NH3-80%DME40%NH3-60%DME

Mode 5 SOI = 20 BTDC

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-75 -60 -45 -30 -15 0 15 30 45 60 75

HR

R (J

/deg

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Cyl

inde

r Pre

ssur

e (b

ar)

Crank Angle (deg)

100%DME20%NH3-80%DME40%NH3-60%DME

Mode 7 SOI = 15 BTDC

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-75 -60 -45 -30 -15 0 15 30 45 60 75

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R (J

/deg

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Cyl

inde

r Pre

ssur

e (b

ar)

Crank Angle (deg)

100%DME20%NH3-80%DME40%NH3-60%DME

Mode 9 SOI = 25 BTDC

Sample Results (P & HRR)

Department of Mechanical Engineering, Iowa State University

• 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 reference: @ 3,250 rpm and 4.3kW running on diesel fuel

• BSEC is 13.656 MJ/kWh, corresponding to a BSFC of 304.8 g/kWh for the current engine.

Results

Department of Mechanical Engineering, Iowa State University

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NO

x (g

/kW

h)

BSEC (MJ/kWh)

Single Injection, 100% DME Mode 5Mode 7Mode 9Mode 11Mode 20Mode 21

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20 30 40 50 60 70 80

NO

x (g

/kW

h)

BSEC (MJ/kWh)

Single Injection, 20%NH3 - 80%DME Mode 5Mode 7Mode 9Mode 11Mode 20Mode 21

0

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0 10 20 30 40 50 60 70 80

NO

x (g

/kW

h)

BSEC (MJ/kWh)

Single Injection, 40%NH3 - 60%DME Mode 3Mode 5Mode 7Mode 9Mode 11Mode 20Mode 21

NOx Emissions

Reference data using diesel fuel

Department of Mechanical Engineering, Iowa State University

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5

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20 30 40 50 60 70 80

NH

3 (g

/kW

h)

BSEC (MJ/kWh)

Single Injection, 20%NH3 - 80%DME Mode 5Mode 7Mode 9Mode 11Mode 20Mode 21

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0 10 20 30 40 50 60 70 80

NH

3 (g

/kW

h)

BSEC (MJ/kWh)

Single Injection, 40%NH3 - 60%DME Mode 3Mode 5Mode 7Mode 9Mode 11Mode 20Mode 21

NH3 Emissions

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NH3 Emissions

0

200

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1400

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20 30 40 50 60 70 80

NH

3 (p

pm)

BSEC (MJ/kWh)

20%NH3 - 80%DME Mode 5Mode 7Mode 9Mode 11Mode 20Mode 21

0

200

400

600

800

1000

1200

1400

1600

1800

0 10 20 30 40 50 60 70 80

NH

3 (p

pm)

BSEC (MJ/kWh)

40%NH3 - 60%DME Mode 3Mode 5Mode 7Mode 9Mode 11Mode 20Mode 21

Department of Mechanical Engineering, Iowa State University

0.000

0.025

0.050

0.075

0.100

20 30 40 50 60 70 80

Soot

(g/k

Wh)

BSEC (MJ/kWh)

Single Injection, 100% DME Mode 5Mode 7Mode 9Mode 11Mode 20Mode 21

0.000

0.005

0.010

0.015

0.020

0.025

0.030

0 20 40 60 80

Soot

(g/k

Wh)

BSEC (MJ/kWh)

Single Injection, 20%NH3 - 80%DME Mode 5Mode 7Mode 9Mode 11Mode 20Mode 21

0.000

0.005

0.010

0.015

0.020

0.025

0.030

10 20 30 40 50 60 70 80

Soot

(g/k

Wh)

BSEC (MJ/kWh)

Single Injection, 40%NH3 - 60%DME Mode 3Mode 5Mode 7Mode 9Mode 11Mode 20Mode 21

Soot Emissions

• Extremely low soot emissions

• HC and CO levels comparable among different fuel mixtures

Department of Mechanical Engineering, Iowa State University

• Injection pressure – positive effects on combustion • To enable combustion of 60%NH3-40%DME

• P_inj=205 bar, SOI= 180 btdc, T_intake= 90 C • Achieved higher load and speed operation

60%NH3-40%DME

2500 rpm & 3.6 hp.

Department of Mechanical Engineering, Iowa State University

NOx and NH3 Emissions

0

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80 100 120 140 160 180 200

NO

x [g

/kW

h]

Start of injection [oCA BTDC]

60%NH3 - 40%DME

60NH3_19_180_160NH3_19_180_260NH3_25_180_3

0

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80 100 120 140 160 180 200N

H 3[g

/kW

h]

Start of injection [oCA BTDC]

60%NH3 - 40%DME

60NH3_19_180_1

60NH3_19_180_2

60NH3_25_180_3

Higher load benefits NH3 combustion; More stable operation; Flexibility in injection timing.

Department of Mechanical Engineering, Iowa State University

• Current test engine • 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)

Perspectives

Diesel fuel 40%ammonia/60% diesel

40%ammonia/60% DME

Ammonia

BSEC (MJ/kWh) 10.3 10.3 10.3 10.3

LHV (MJ/kg) 42 32.6 24.5 18.6

Fuel rate (kg/kWh) 0.245 0.316 0.420 0.554

Fuel price ($/kg) $1.180 $0.950 $0.704 $0.605 Fuel energy cost ($/kWh)

$0.29 $0.30 $0.30 $0.34

Fuel cost based on $3.7/gal diesel, $550/ton ammonia, $700/ton DME

Department of Mechanical Engineering, Iowa State University

DISI NH3 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

Department of Mechanical Engineering, Iowa State University

Gaseous NH3 Injection

• Fuel pump and storage operate on liquid basis • Injection line pressure approx.

35 bar

• Injection line heated to achieve gaseous fuel • Temperature required 60°C • Heat provided by heat tape • Expansion chamber to

compensate for dramatic volumetric change upon vaporization

Pump

Ammonia Bottle

Pressurization Tank

Surge Tank

Pressure release Valve

Pressure Reducing Regulator

Fuel Scale

Department of Mechanical Engineering, Iowa State University

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

Department of Mechanical Engineering, Iowa State University 21

Summary • CI engines using ammonia

• 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