2009 DEER Conference - Department of Energy · 2009 DEER Conference Novel Approach to Determine Oil Dilution 1. A Novel Approach in Determining Oil Dilution ... Blowby separator with

2009 DEER ConferenceNovel Approach to Determine Oil Dilution

1

A Novel Approach in Determining Oil Dilution Level on a DPF Equipped Vehicle as a Result of

Regeneration

DEER August 6th

2009, Dearborn, MI USA

Harsha

Nanjundaswamy, Marek

Tatur, Dean TomazicFEV

Inc., Auburn Hills, MI USA

Andreas Wiartalla, Matthias Lamping, Thomas KoerferFEV

Motorentechnik

GmbH, Aachen, Germany


2

Introduction

Fundamentals of novel approach

Results

Test setup

Test plans

Test data analysis

Conclusion

Table of Contents


3

Oil dilution is detrimental to engine durability

More DPF and NAC equipped medium and light duty vehicles

In-cylinder late cycle diesel injection for regeneration and more

Critical for oil dilution

Challenge on positioning post injection strategy vs. oil dilution

Estimating in-use oil dilution not well understood other than expensive laboratory tests

Lambda based in-use oil dilution estimation

Conrod bearing wear

Visc

osity

Temperature

Visc

osity

Temperature

Visc

osity

Temperature

Visc

osity

Temperature

Oil dilution

Conrod bearing wear

Visc

osity

Temperature

Visc

osity

Temperature

Visc

osity

Temperature

Visc

osity

Temperature

Oil dilution

Introduction

Air

Fuel

HC

Fuel impingement or fuel vapor absorption.

This process is enhanced by late post

injection

Oil layer on the cylinder

walls

Blow by

Fuel diluted oil

Oil + Fuel

Air

Fuel

HC

Fuel impingement or fuel vapor absorption.

This process is enhanced by late post

injection

Oil layer on the cylinder

walls

Blow by

Fuel diluted oil

Oil + Fuel


4

Lambda balance Fuel balance

Diesel-Loss [ DL

] is estimated as

POSITIVE diesel loss = Oil dilution

NEGATIVE diesel loss = Fuel evaporation

Mass of fuel loss to oil sump : mFL

= mF

* DL

S = Spindt = f(Exhaust Composition)

and / orS = Sensor

mFuel

V = mAir

mFuel * AFR

mAir mExhaust

Diesel FuelEngine Oil

Balance Border Line

Blow-By

EGR

DieselLoss (DL)

S = Spindt = f(Exhaust Composition)

and / orS = Sensor

mFuel

V = mAir

mFuel * AFR

mAir mExhaust

Diesel FuelEngine Oil

Balance Border Line

Blow-By

EGR

DieselLoss (DL)

DL =S - V

S* 100 %DL =

S - V

S* 100 %

Fundamentals : Novel approach methodology

mFL

mE

mF

mFL

mE

mF


5

Post injection

DPF regeneration

NAC regeneration

NAC desulfurization

In-cylinder soot reduction Fuel in oil

Fuel vapor absorption

Fuel injection wall wetting

Late cycle injection

Cylinder charge leak and condensation

Fuel evaporation

Diffusion off the oil layer in cylinder

Blow by

Engine speed

BMEP

Post injection strategiesFundamentals : Oil dilution phenomenon

1

2

3

4

5

6

7

8

1 Fuel absorption by oil film

2 Blow-by transports fuel

3 Oil feed from sump to liner film

4 Oil drain back into the crankcasecarrying absorbed fuel

5 Breather gases leave the crankcase carrying vaporized fuel

6 Part of the liner film is burnt during combustion stroke

7 Desorbtion of fuel components

8 Fuel desorbtion into the breather gases

1

2

3

4

5

6

7

8

11

22

333

444

555

66

77

88

1 Fuel absorption by oil film

2 Blow-by transports fuel

3 Oil feed from sump to liner film

4 Oil drain back into the crankcasecarrying absorbed fuel

5 Breather gases leave the crankcase carrying vaporized fuel

6 Part of the liner film is burnt during combustion stroke

7 Desorbtion of fuel components

8 Fuel desorbtion into the breather gases


6

Data analysis

Vehicle setup for oil dilution estimation

ECU

Engine Aftertreatment system

Lambda OUT

Lambda IN

Results : Test setupTEST CELL

Coriolis

type fuel mass flow measurement

Dynamic high accurate air mass flow measurement

Blowby

separator with bypass

Complete exhaust instrumentation

Lambda sensor

Emissions measurement and Lambda exhaust

Smoke and PM measurement

Temperature and pressure

VEHICLE

Air and fuel measurement through ECU

Vehicle instrumentation to gather temperature and pressure signals

Exhaust Lambda sensors

Test cell setup for oil dilution estimation

EngineBlow by separator with bypass

INTAKE

Air mass flow measurement

Fuel mass flow

measurement

EXHAUST

DOC and NAC

DPF Tailpipe

LambdaGaseous EmissionsSmokePMTemperature Pressure

Combustion analyzer

EngineBlow by separator with bypass

INTAKE

Air mass flow measurement

Fuel mass flow

measurement

EXHAUST

DOC and NAC

DPF Tailpipe

LambdaGaseous EmissionsSmokePMTemperature Pressure

Combustion analyzer


7

Results : Test plan

Test cell Oil dilution estimation

Oil change interval simulation through vehicle test correlation

ECU executed in-cylinder post injection based regenerations

Extended study

Extended oil change interval

Blow by effect

Oil ageing study over time

Vehicle tests

Statistics of diesel loss for regeneration of DPF & NAC as well as normal engine operation in both city and highway driving

Correlation of the vehicle tests to test cell for controlled engine testing to study the diesel loss method

Regular operationCool down

DPFRegeneration

Cool downRegular operation

Engine speed

Torque

Soot load in DPF

Pressure drop

DPF temperature

Regular operationCool down

DPFRegeneration

Cool downRegular operation

Engine speed

Torque

Soot load in DPF

Pressure drop

DPF temperature

Time

Regeneration

Fuel in 5537 gmFuel out 5017 gmDiesel loss 9.39 %

Fuel IN Fuel OUT

NO RegenerationFuel in 2003.45 gmFuel out 2087.12 gmDiesel loss -4.17 %

Die

sel l

oss

[%]

-20

-10

0

10

20

30

40

50

Calculated diesel loss


8

Results : Test data analysis

Regeneration mode Non Regeneration mode

Time

Lam

bda

[-]

1.01.52.02.53.03.54.0

Lambda - IN Lambda - OUT

Acc

umul

ated

fuel

[g]

-500

50100150200250

Lambda IN < Lambda OUT

Lambda IN > Lambda OUT

Fuel

loss

[g/s

]

-0.5

-0.3

-0.1

0.1

0.3

0.5

Zero line

Negative

Positive ∆

= 0.08

∆

= 0.03

Regeneration mode has dominant diesel loss

Regular engine operation mode is dominated by fuel evaporation


9

Results : Test data analysisFu

elev

apor

atio

n [%

]

-10-8-6-4-202

Time [hr]0 2 4 6 8 10 12 14 16 18

Fuel

loss

[%]

05

101520253035

Time [hr]0 2 4 6 8 10 12

Fuel loss during regeneration andsimilar aggressive oil dilution events

Fuel evaporation during normalengine operation

Net

Oil

dilu

tion

[%]

0

5

10

15

20

25

Time [hr]0 5 10 15 20 25 30

Net oil dilution

Aggressive oildilution rates

Dominant fuel evaporationminimizing the dilution rateReduced oil dilution rates

due to dominant fuelevaporation rates

Weak fuelevaporation rates

Aggressive fuelevaporation rates


10

Test data analysis boundaries

Tight control on evaluating oil and fuel consumptions

Correlation between vehicle and test cell engine was established also on miles vs. fuel consumption

Steady state engine operating points chosen based on vehicle test results to meet fuel evaporation rates

Focus on worst case scenario

Actual analysis of the oil done through gas chromatography

Good correlation between estimation vs. actual60

70

80

90

100

110

120

1

Perc

ent v

alue

[%]

Gas chromatographyFEV oil dilution estimation

∆ of 2%

Results : Test data analysis


11

More aggressive oil dilution is seen with fresh oil

As the oil dilution increases so does the fuel evaporation rates

As the dilution progress the negative fuel loss or fuel evaporation balances the dilution levels

Blowby

plays a role in fuel evaporation

Zero line

Acc

umul

ated

fuel

in o

il [g

]

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

Time [sec]0 50 100 150 200 250

Fresh Oil 10 % diluted oil

Over time this fuelevaporation tunrs

into fuel loss into oil

Time

Acc

umul

ated

Fue

l Los

s [g

]

-25

-20

-15

-10

-5

0

5

10

15

At higher oil dilution levels thefuel evaporation overrides the

fuel oil dilution

8 % Oil dilution 18 % Oil dilution 23 % Oil dilution

Results : Test data analysis -

Study findings


12

Acc

umul

ated

Fue

l Los

s [g

]

-30

-25

-20

-15

-10

-5

0

Time [sec]0 200 400 600 800 1000 1200

Base - SETUP 1 Filtered Blow-By - SETUP 2

Blow byfiltering

1 2

2

1

With blowby and no fuel fume separation [1] it is clear that there is more fuel evaporation is observed

With blowby with fuel fumes separation the net fuel evaporation is greatly reduced

This proves the fact that fuel evaporation from oil is present and greatly influenced by blowby


Study findings


13

With increase in oil dilution the fuel loss rate also reduces due to saturation effects

As observed earlier the fuel evaporation rates dominate with increase in oil dilution

Over certain oil dilution level there was no significant increase in oil dilution as the fuel evaporation rates balance out the dilution levels

However these trends are subject to engine operation and thermodynamic boundaries in which it operates


Study findingsFu

el lo

ss ra

te [

g/m

ile]

1.0

1.1

1.2

1.3

1.4

1.5

Fuel

eva

pora

tion

rate

[g/m

ile]

-0.4-0.3-0.2-0.1-0.00.10.20.30.4

Baseline operation

Regeneration operation

Oil

dilu

tion

[%]

2

6

10

14

18

22

Miles [x 1000]0 2 4 6 8 10 12 14 16 18 20


14

Findings

Oil dilution rate is a function of dilution effects such as late

post injection and evaporation rates during regular operation

Fuel evaporation of the oil layer is subject to blowby rates and

oil temperatures

The oil dilution rate varies with respect to dilution level, so does the evaporation rates

Oil dilution estimation is subject to accuracy of the measurement

0.0

5.0

10.0

15.0

20.0

25.0

30.0

1 hr operation 2 hr operation 2000 5000 10000 17500

Miles

Oil

dilu

tion

[%]

Gas chromatographyFEV oil dilution estimation

DPF regeneration only


Statistics


15

Conclusion

The novel approach determines the oil dilution within 2 –

20% accuracy

This approach can be easily adopted for developing optimum engine calibration meeting performance, emissions and oil dilution

This novel approach of oil dilution estimation would help avoid issues that may arise with fixed oil change intervals

Oil dilution degradation as a result of varying drive cycle

Avoid severe degradation of oil quality before specified oil change interval

At many instances increase the oil change interval beyond specific miles limit

Implementation of this methodology does not demand new sensors but a new strategy

Accuracy of the measurement signals and noise elimination is crucial for the quality of estimation

Documents

2009 DEER Conference - Department of Energy · 2009 DEER Conference Novel Approach to Determine Oil Dilution 1. A Novel Approach in Determining Oil Dilution ... Blowby separator with