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Masaaki KATO

Hisaharu TAKEUCHI, Yuuji SAKURAI (DENSO CORP. )

Shuichi KAJITANI, Yuko SHIBASAKI (Ibaraki University)

Masahiro TAMAKI (TOYOTSU CHEMIPLAS CORP.)

The seventh Asian DME Conference,

Niigata Japan, 16-18 November 2011

A Study of Diesel Nozzle Tip Wear

in the Fuel DME

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Outline of presentation

1. What is DME? DME (Dimethyl Ether) properties and

concern for diesel fuel injection system

2. Compare the nozzle wear test rigs with the real engine conditions

3. Evaluate the effect of several lubricant additives on decrease the wear of nozzle by the new Rig

4. Evaluate the corrosion effect of impurity water in DME on nozzle

Aim: To study and overcome the nozzle wear

in use of engine fueled DME

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1. What is DME?

4/21

Characteristics

① Gaseous fuel easy to liquefｙ

② High cetan number suits for Diesel engine

③ Contain no sulphur →Creates no SOx

④ NOx is less than Diesel fuel

⑤ PM≒0 （Oxygenated fuel no C-C bond)

⑥ Can be manufactured various sources

( NG, coal, biomass ･･･)

DME（Dimethylether）?

Promising alternative fuel for Diesel engine

CH3OCH3

5/21

DME Physical Properties and Concerns for FIS

Lots of Subjects for fuel injection system

Property

Viscosity@25-80℃

Diesel oil DME

Bulk modulus of elasticity

Vapor pressure @25°C

Density@20°C

Calorific value

0.25-0.15cSt 3cSt

100MPa～1000MPa Depend on Temp. & Pressure

610kPa (3MPa@90℃） Depend on Temp.

1400MPa

840kg/m3 667kg/m3

42.7(MJ/kg) 28.8(MJ/kg)

－

Critical point 127℃, 5.3MPa ー

Specific heat @80°C 2090J/kg/K 2247

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2. Nozzle wear test rigs

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Diesel Fuel Injection System(FIS)

and Nozzle Tip

Fuel spray and

flame

Combustion

chamber Engine piston

Nozzle Tip

High Pressure

Supply Pump

Fuel Tank

Leak line

Injector

Common Rail & high pressure line

Leak line

Common Rail FIS

8/21

Fuel Temperature in Nozzle Sac on Engine

DME shows higher temperature and larger drop in sac than diesel fuel

Injector

Thermocouples’

leading wires

0

100

200

300

400

500

-40 -20 0 20 40 600

0.2

0.4

0.6

0.8

1

1.2

Crank angle [deg.]

Pme=0.6[MPa]

Injection pressure=20[MPa]

Static injection timing=-10[deg.]

Sac temp.

Tip temp.

DME

DME 50%,

Diesel fuel 50%

Diesel Fuel

DME

DME 50%,

Diesel fuel 50%

Diesel Fuel

Diesel Fuel

Tem

per

atu

re[℃

]

Nee

dle

lif

t [m

m]

Needle lift

TDC

Critical temp.

Nozzle

Sac thermocouple

150μm

Tip thermocouple

250μm

Body

Needle

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Nozzle temperature with

Diesel Fuel Operation

Nozzle temperature with

DME Operation

Test Engine： Yanmer NFD13-K

Single cylinder

BoreｘStroke:φ92x96

Swept volume:638cm3

Nozzle hole dia.xNo.：φ0.175x4

Test condition：

Ne=960rpm

BMEP=0.6MPa

Numbers in figures show

Temperature [degree Celsius]．

Temperature of Nozzle Body during

Engine Test

200℃<seat temp. & Diesel fuel≒ DME

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FIE Wear Test Rig with Diesel Fuel

Motor

Injector

Supply pump

Argon Gas

(against ignition)

Injector Holder

w/heater

Common

rail

Fuel tank

:atoms. press. Mist filter

Oil cooler

Release to air

Heated up nozzle to engine condition with diesel fuel

Temperature of nozzle：up to 240℃

Source:[3]

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HFRR：High Frequency Reciprocating Rig

Examination on actual nozzle is necessary

Outline of equipment Result of test

HFRR cannot predict real wear

Wear comparison: HFRR vs FIE rig

WSD＜460〔μm〕・・・Japan&EU

Test Fuel

x

y

Lubricity evaluation equipment

decided by ISO

Consider

from wear of

ball 0

0.5

1

1.5

2

2.5

3

0 100 200 300 400 500 600 N

ozzle

seat

wear

on

FIE

rig

Wd (

μm

)

Lubricity improvement additive

No additive

Fuel ： Diesel fuel

Prediction

Result

WSD by HFRR(μm)

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NEW DME Nozzle Wear TEST RIG

3600[ rpm] 1000[ N]

Impact load=1kN

3600[ rpm]

Motor

Pump

Nozzle

1000[ N] Stepper

motor

DME circulate

3600[rpm]

Nozzle Inlet

pressure

RIG Fuel circulation part

Revolution speed

Fuel tank

Control Unit

Load control part

Concept

Patented: Japan, China , USA

・Circulation of Liquefied DME

・Use actual nozzle ・Improve experiments accuracy, small and compact

13/21 Test Area of Pressure & Temperature of Engine

& Wear Test Rigs, and DME phase

Temperature [degree Celsius]

Pre

ssu

re

[MP

a]

0

127

5

DME

Critical point

127C,5MPa

DME Super critical phase DME

liquid phase

DME in nozzle sac in eng.

Temp.=100~200C

Press.<100MPa

DME upstream nozzle seat in eng.

Temp.=40~100C

Press.<100MPa

HFRR

60C,1bar

FIE wear test rig

Temp.:Fuel(diesel) 40~60C

Nozzle120～240C

Press.:Inj.180MPa, back1bar

DME Nozzle

wear test rig

<40C,<1MPa

DME gaseous phase

300

Temp. of nozzle

body seat in engine

200~300C

10

-25

MPT-HFRR

60~100C

<10MPa

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3. Effect of lubricant additives

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Wear on Nozzle Wear Test Rig & Engine

Fuel：DME Impact number：1X107

Needle

seat

Shape before & after test Photo x50

Test condition

Wear

depth：2.4μm

5μm/div

0.2mm/div

After

Before

5μm/div

0.2mm/div

Wear

depth:

3.4μm

After

Before

Test time

46hr (1×107 )

1kN

93hr (1×107 )

Measuring path D

ME

No

zzle

Wea

r te

st r

ig

En

gin

e

Test rig simulates the wear of nozzle on engine

Ne=960rpm

BMEP=0.6MPa

A

C

B

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Fuel Additive Effect of Wear Reduction

on Nozzle Seat

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

0 50 100 150 200 250 300

Fuel additive concentration（ppm）

Sea

t w

ear

dep

th(B

od

y+

nee

dle

)[μ

m] Diesel

Neat DME

DA03P

DA03P+H2O 200+1%

DA04F

DA04F+H2O 30+1%

DA04F+H2O 300+1%

Impact number10^7, Load1kN

Additive

ppm

+water%

Include H2O

No H2O

200~300ppm of additive is enough for wear reduction

Additive

DAxxP: Polymer type

DAyyF: Fatty acid type

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4. Influence of water

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Oxygen concentration on wear tested needle

02468

1012141618

DIESEL DA02F DA02F+H2O DA04F+H2O DA03P+H2O

（300ｐｐｍ） （300ｐｐｍ+1％） （30ｐｐｍ+1％） （200ｐｐｍ+1％）

10＾7 10＾7 10＾7 10＾7 10＾7

Ox

yg

en c

on

cen

trat

ion（

％）

DA02F+H2O

(300ppm+1%)

Analyzer:EDX(Energy

Dispersive X-ray analyzer)

DIESEL fuel DA02F

(300ppm)

DA03P+H2O

(200ppm+1%)

DA04F+H2O

(30ppm+1%)

Impact number 10^7, Load

1kN

DME

Corrosion by water was shown even under low temperature

Needle seat portion Needle tip

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0

1

2

3

4

5

6

7

0 0.5 1 1.5 2 2.5 3 3.5 4

Wear depth of needle[μm]

Wear

depth

of

body [

μm

]

Diesel

NeatDME

DA03P 200

DA03P+H2O 200+200

DA03P+H2O 200+0.03%

DA03P+H2O 200ppm+500ppm

DA03P+H2O 200ppm+1%

DA03P+H2O 300ppm+1%

DA04F 30ppm

DA04F+H2O 30+1%

DA04F+H2O 300+1%

DA04F 200ppm

DA04F+H2O 200+1%

DA03P 300ppm

DA03P 500ppm

Impurity & Temperature Effect on

Nozzle Seat Wear Symbol

②NEAT DME

④=③+water

① Diesel fuel (rig)

③=②+additives

Diesel fuel (FIE rig)

200℃

120℃

Test should be on Engine, high temperature condition

Water 300ppm

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Conclusion

1) There is the large wear at the needle seat in case of fuel DME. Although HFRR cannot evaluate the wear at the seat, newly developed prototype wear test Rig can evaluate the seat wear.

2) Results of the new rig are some of the fatty and the polymer type additives is effective on wear resistance for nozzle seat.

3) The concentration of each additive is 300ppm enough to decrease the wear.

4) Impurity such as water brings nozzle more oxidized corrosion. The ratio of impurity water should be less than 300ppm

5) The effect of additives and impurities on engine should be studied, because the temperature of nozzle on engine is higher than the rig.

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