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


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


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


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)


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


0

1

2

3

4

5

6

7

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


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


0

5

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15

20

25

-10

0

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40

50

60

70

-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

0

5

10

15

20

25

-10

0

10

20

30

40

50

60

70

-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


0

5

10

15

20

25

-10

0

10

20

30

40

50

60

70

-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


Sample Results (P & HRR)


• 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


0

5

10

15

20

25

30

20 30 40 50 60 70 80

NO

x (g

/kW

h)

BSEC (MJ/kWh)

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

0

5

10

15

20

25

30

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

5

10

15

20

25

30

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


0

5

10

15

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25

30

20 30 40 50 60 70 80

NH

3 (g

/kW

h)

BSEC (MJ/kWh)


0

5

10

15

20

25

30

0 10 20 30 40 50 60 70 80

NH

3 (g

/kW

h)

BSEC (MJ/kWh)


NH3 Emissions


NH3 Emissions

0

200

400

600

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1400

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1800

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


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)


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)


Soot Emissions

• Extremely low soot emissions

• HC and CO levels comparable among different fuel mixtures


• 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.


NOx and NH3 Emissions

0

5

10

15

20

25

30

35

40

45

50

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

5

10

15

20

25

30

35

40

45

50

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.


• 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


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


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


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


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

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

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