Tribological challenges in flex fuel engines.

TRIBOLOGICAL CHALLENGES IN FLEX FUEL ENGINES

1

Amilton Sinatora29/09/2014

Topics

2

1. The TRIBOFLEX consortium

2. Selected topics on engine tribology

São Paulo

Ribeirão PretoPirassununga

São Carlos

Piracicaba

Bauru Lorena

State University

São Paulo State

Soutwest Brazil

Created in 1934

72 unities: including

• 37 colleges

• 4 museums

• 4 hospitals

São Paulo University

São Paulo University

Item 1989 2012 %

Students

Under. 31 897 58 303 + 83

MsC 8 486 13 836 + 63

Dr. 4 428 14 662 + 231

Total 44 811 86 801 + 100

Academic 5 626 5 860 + 4

Stu/acad 8:1 15:1

Staf 17 735 16 839 - 5

Feb. 2016!

~1986

in numbers Created in 1893 Absorved by USP in 1934 24 buildings with 152.500 m2

15 Engineering departments 447 Scholar (-2,5% 2009) 103 laboratories 4.700 undergraduated students 791 master degree students (2013) 761 doctoral students (2013) 5% increase total students 2009 -2013

Polytechnic School - 1893

In numbers 51 Scholars 13 laboratories 70 undergrad.

Mechanical Engineering Department

The Surface Phenomena Laboratory

in numbers

Created in 1994 07 Scholars 04 Pós doc fellows 14 doctoral students 09 master degree students 06 Senior reseachers 08 undergraduated students 03 technicians 02 administrative support

Doctoral Students

Ana Júlia, Vanessa, Pablo, Guilherme, Gil, Eduardo, Eleir, Felipe, Juan, Roberto, Alexander, Franco, Jimmy e Paulo

Master Degree Students

Marcio Silva, Andre, Luigi, Marcio, Renata, Tiago, Arthur, Gustavo e Iramar

Senior Researches

Marcos, Philip, Cristiano, Luiz, Manuel, Newton

Pós Doc Fellows

Erika, Tiago, André, Tomanik

Undergraduated Students

Felipe, Vinicius Campos, Fernando, Henrique, Vinicius, Lucas, Edemar e Arthur

Technicians

Raquel, Fabio e Francisco

Administrative Support

Silene e Sidney Academic

Tanaka, Izabel, Roberto, Amilton, Mario, André, Rodrigo

1. Project history and scope

2. TRIBOFLEX starts

3. Project structure

4. Project status

5. Project outcomes

6. Project chalenges9

1. The TRIBOFLEX consortium

Ago 2009 – Workshop at MAHLE

The project joining competitors has pre-competitive scope and a strong focus to education on combustion engine tribology. Such human resources should be able to support the R&D on engines using bio-fuels, both in the industry and the P&D centers. 10

Rings: Premature wear spalling Gustavo Volci ME 2007 UFPR

Valves: Leakage

power loss.

1 .Scope /History - 2009

There was a perception that the Brazilian Flex fuel engines had relevant tribological challenges.

Such challenges are peculiar and important both to the industry and academy.

11

Erdermir, 2012

1 .Scope /History

Erdermir 2012

Worldwide trend to reduce fuel consumption. Brazil INOVARAUTO

Large part of the engine energy is lost to overcome friction

The Project scope was defined through several workshops with both automotive companies, suppliers and universities. The project content was also defined by the companies interests, participants expertise, budget and rules to be partially funded by the Government funding agency (FAPESP). The project wasexpect to last 3 years, 1.2 Mi R$/year, about 100 k R$ per company participant per year

1 .Scope /History - 2009 – 2012 Legal/bureaucratic PARKOUR

Workshps. Scope - focus - expertise - interess- funding

Technical workshops. Companies - universities

- suppliers - invited speakers

FAPES. Projec evaluation /aproval /

signature

USP Legal procedure / revision of the project /

adjust budget

Companies - USP inovation agency -

FAPESP

2009 2010 2011

2012

12

1 .Scope /History - 2009 – 2012 Legal/bureaucratic PARKOUR

UniversitiesInexperienced to deal with complex projects considering the legal, technical and management aspects (First USP consortium)

Legal/ bureaucratic. It was necessary to adapt the procedures to the paperwork. Inexperienced to fulfill the FAPESP formal requirements of the FAPESP support program portfolio;

Technical. Fundamental knowledge however, lack of experience and technical expertise in the field;

Management. Previous experience with one-to-one project, academic network projects. No experience with supplier-costumer nor competitor-competitor projects.

FAPESPThe same …(First FAPESP consortium)

Legal/ bureaucratic. The routine to evaluate the consortium was the same used to evaluate one-to-one-partner projects. Reviewers complained on the percentage of FAPESP X companies financial contribution. Some suggested that the project should be fully supported by the companies.

Technical. Reviewers complained: Must include senior person from automotive field. The deliverables of the project were ill defined. There are no clear technical benefit to the companies nor to the market….

Consortium scope and organization did not adjust to any of FAPESP or USP previous procedure

Approval was only achieved due to the commitment of the companies, FAPESP and USP.

13

2 . TRIBOFLEX Starts....and then,... Tupy joins the consortium!!Legal/bureaucratic PARKOUR

Universities - FAPESPInexperienced to deal with complex projects considering the legal, technical and management aspects (First time that a newcomer (new partner) joins the first USP / FAPESP consortium!)

14

3 . TRIBOFLEX Structure

Structured knowledge on tribology focused in:

- tribological coatings (films and oxides)

- texturing / topography on engine components

- affinity between lubricants and components (films and materials)

Structured knowledge in the modelling and experimental analysis of the tribo-systems

- ring/lube/borevalve/interfacial media / valve seat

Project contribution if successful

Multi scale (centimeter to nanometer). Multidisciplinar (chemistry, material science,

metallurgy, mechanical engineering). Multi skill

(mathematical, computational, experimental).

15


Four macro-projects

00- Tribological Characterization of flex-fuel engine components0.01 – Wear mechanism on worn parts

01- Ring-Lube-Bore Tribo system (sl 17)1.01 – Graphite and bore wear mechanisms

1.02 – Physicochemical interaction of oxides and lube film1.03 – Lubricity of degraded oils and the ring materials

1.04 – Low friction films for piston rings

02- Valve-interfacial media-valve seat tribology2.01 – Topography and tribological performance of valves

2.02 – Influence of temperature and frequency on wear2.03 – Valve bench tests for valves and valve seats

2.04 – Metal and ceramic materials for valves03- Modeling of materials and loadings

3.01 – Modeling of materials / films under thermal /mechanical loads3.02 – Modeling ring/bore friction under lubrication

04 – Education of specialized human resources4.01 - Road Show to attract talents for the project

4.02 – Courses for basic formation on engine tribology4.03 – Graduate studies for regular employees from companies

4.04 – Doctor thesis on topics related to the macro-projects4.05 – International experts

Expresses broad companies interests. Themes were set after 2009 workshops

Expresses mostly the academic expertise and/or on going research X 16

3 . TRIBOFLEX Structure – Engine systems

Ring – Lube - BoreValve - Seat

Supplier commitment and expertise Relevant to the auto companies


Four macro-projects

00- Tribological Characterization of flex-fuel engine components0.01 – Wear mechanism on worn parts

01- Ring-Lube-Bore Tribo system (sl 17)1.01 – Graphite and bore wear mechanisms

1.02 – Physicochemical interaction of oxides and lube film1.03 – Lubricity of degraded oils and the ring materials

1.04 – Low friction films for piston rings

02- Valve-interfacial media-valve seat tribology2.01 – Topography and tribological performance of valves

2.02 – Influence of temperature and frequency on wear2.03 – Valve bench tests for valves and valve seats

2.04 – Metal and ceramic materials for valves03- Modeling of materials and loadings (sl 18)

3.01 – Modeling of materials / films under thermal /mechanical loads3.02 – Modeling ring/bore friction under lubrication

04 – Education of specialized human resources4.01 - Road Show to attract talents for the project

4.02 – Courses for basic formation on engine tribology4.03 – Graduate studies for regular employees from companies

4.04 – Doctor thesis on topics related to the macro-projects4.05 – International experts

Expresses broad companies interests. Themes were set after 2009 workshops

Expresses mostly the academic expertise and/or on going research X 18

2 Tribo tests3 Topography analysis

4 Surface chemistry and properties1 Characterization

3 . TRIBOFLEX Structure – Modeling + Experimental


Industry x academySupplyer x customerCompetitor - competitor

MultiscaleMultidisciplinarTheoretical x experimental

5th Steering comitee USP 27/03/2014

12th Tech. Meeting USP 27/03/2014

2nd Int. Course USP 02-03/10/2013

Background courses to the participants

20

4. Project Status

First Master in Engineering Dissertation fully developed in the TRIBOFLEX consortium. 13-03-2014. Eduardo Trindade PETROBRAS

First Doctor Engineering Thesis fully developed in the TRIBOFLEX consortium. 11-06-2014. Ane Cheila Rovani (now at UFPR)

Project plan 2009

Project submission dec. 2009

Contract final version: dec. 2012

First report sept 2013

Second report sept 2014

Next steps

Final report sept 2015

21

Such human resources should be able to support the R & D on engines using bio-fuels, both in the industry and the P&D centers.

Industry R & D staff education

1 ME sudent1 Dr student

1 ME sudent1 Dr student

1 Engineer1 Tecnician1 Dr studentTwo years research project

1 Pos Doc Fellow1 Dr Student

TRIBOFLEX

5 . Outcomes

22

The project has pre-competitive scope and a strong focus to education of human resources on combustion engine tribology

1st Course on Tribology of Automotive Components. Recife 14 -18th july 2014

1 Undergraduate student 1 Dr student1 Academic

1 Academic

TRIBOFLEX

5 . Outcomes

23

6. Project Chalenges / future

Complex projects demands time consuming management and control: Provide resources to hire specialists (chief engineer, administrative staff)

Legal – bureaucratic issues: Help to build new procedures

Companies x University mindset: work together and solve.

24

http://www.eusci.org.uk/

articles/what-happens-when-scientist-

becomes-manager)

Knowledge gap (university and companies) is large: Intensify and improve the international cooperation

A lot of information and knowledge is produced: Provide resources to knowledge management. Communicate the project to the members and the society

Find nice themes to TRIBOFLEX II

Daily topics

Long term topics


- On going research -

2 Tribo tests3 Topography analysis 4 Surface chemistry and

properties1 Characterization

2.1 Bore characterization

2.2 Bore wear measurement

2.3 Friction and wear tests


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Ring and Bore afterGlobal Engine Durability450 h Wide Open Throttle

2.1 CHARACTERIZATION – RING - BORE

New E 100E 20

Dinécio Santos Filho / Hélio Goldenstein

Carbonaceous deposits E85BorePiston (ring pack + pin region)

Brigheter regions (both motors) Top dead center (TDC)


Honned bore

surfaceTop and side view

E 85 / E100 Top dead center. Vertical scratches. Residual honning grooves, folded metals

Grooves

Folded metal

E 100E 20

Vertical grooves – abrasion marks top

dead center



TDC

BDC

Mid strokeVertical grooves abrasion marks along the bore height

TDC transverse section. Squeeze graphite and cracks. Metallic wear debris due to fatigue process.


TDC BDCMidSummit and core wear 28

2.1 CHARACTERIZATION – RING - BORENew E 20 E 100

Ring wear more intense in the ethanol engine test


Expand the characterization (check)

Quantify the wear (in a easy way)

Estimate the energy loss due to vertical scratches

Evaluate ring and cylinder material microstructure and properties

Improve the computer model

piston

piston ring

Cylinder wall

Combustion chamber

lubricant

lubricant

30

2.2 Cylinder bore wear measurement

Rafael Obara

TDC

BDC

Mid Stroke

Literature: Superpose the Abbot Firestone curves using the maximum height frequency as criteriumCabanettes 2012

Cast iron cylinder liner

31

TD

C

BD

C

UnwornWorn

Rafael Obara 2014

1. Obtain a 3D profile (9h work!)

2.Obtain a 2D profile (height profile)

3. Remove 10% summits

4. Calculate average value from each 1024 measurements

5. Calculate relative height = (hunworn

– hworn

) ! 2D wear estimative! (Blue)

6. Find a literature model (Green)

7. Build your own statistic Vmc model (Red)

8. Compare both with the relative height

2.2 CHARACTERIZATION Quantify the wear

R2 = 0,6

R2 = 0,4

2.2 CHARACTERIZATION

Ring x bore and valve x valve seat characterization33

Mixed Lubrication

2.2 Friction and wear measurements- Mixed lubrication -

2.2.1 How are we measuring2.2.2 Effect of anisotropy2.23 Material – base line2.2.4 Material - maleable2.2.5 Material – deep etching2.2.6 Additives + nano 34

Ball on plateOil dropletesASTM D 6425. 52100 ball x 52100 disc Polished2 h, 50 Hz, 300 N. tests50, 80, 120, 15°C

2.2.1 How are we measuring?

Eduardo D. Trindade Alexander Zuleta D.

Optimol SRV Tribometer Round robin test – 2013

40 labs duplicated results,ASTM D6425-05 (friction and wear)

Repeatability – r Reproducibility - R

35

LFS results plotted vs normalizad average friction coefficient round robin results

Our COF results < 2σ !


36

Repeatability r = 0,01 Reproducibility R = 0,03

3 Oils COF ~ 0,13 r 0,12 to 0,14 R 0,10 to 0,16

A better oil (surface treatment, material, roughness) should result in COF max 0, 10!

COF (group average)


37

2.2.2 Effect of TOPOGRAPHY Anisotropy

Ball (SAE 52100 700HV30

) on disc (H13 610 HV

30)

Ball Roughness < 0,050 µmBall radius 5 mmReciprocating 10Hz, 35NMax speed 90mm/sSAE 5W30K viscosity @40C 60,1cStK viscosity @100C 10,5cSt

Parameter Average 8 spots

'Sa' 0,345

'Sq' 0,450

'Ssk' 0,491

'Sku' 4,754

'Sp' 2,233

'Sv' 1,334

'Sz' 3,567

'Vm' 0,030

'Vv' 0,569

'Vmc 0,377

'Vvc' 0,521

'Vvv' 0,048Strong effec of topograpy orientation on avg COF besides the roughness parameter are the same.Vinicius Campos Tiago Cosseau


COF along a stroke and ball displacement with time. Speed is zero at the broken lines (end of stroke) and it is maximum at the mid point. COF scale is not centered on zero

COF is almost constant – blue line Boundary lubrication behaviour.

39


600,05 600,15

Green and blue COF measured paralel to the milling grooves. Straight lines (boundary lubrication)

Red and light blue COF measured perpendicular to the milling groves – The COF increases at the edges of the wear scar (boundary lubrication). Minimum COF (mixed lubrication)

t(s)


Experimental x calculated COF both orientation.

Calculated: Deterministic model (hidrodinamic and asperity pressures) to calculate lubricant and asperity shear stresses). µ boundary from measurement

COF

4- Mixed regime model (deterministic)

Build a 2D model

Consider topographic change with time

Test with plain oil (at the same viscosity) to check boundary COF contribution

Better boundary COF to the model

41

piston

bore

ring

2.2.3 Bore and ring materials friction and wear base line

Marcos Ara

Nitreded stainles steel ringRing x bore sample asemblyGray cast iron bore

64 samples extracted from engine block + ring pa

F: 50N , 20HzStroke: 2.5 mmT: 25 COil: PAOFully flodedSurface: Milledt: 6, 60, 600 min

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t (min)

log t (min)

COF

~ 50% COF reduction Δ = 0,05 > R – smoother surface?Steady satate friction after 10 h?

Wear rate each test period.Wear steady state after 60 min in advance to COF steady state

Overal wear rate

Main texture changes within 6 min test

ParamNew 6

min60 min 600 min

Sa (m)

0.23 0.029

0.19 0.039

0.17 0.021

0.16 0.024

Sq (m)

0.30 0.039

0.24 0.053

0.22 0.027

0.22 0.057

Ssk (m)

-0.95 0.400

-1.23 1.756

-0.60 0.573

-1.17 1.329

Sku (m)

5.73 2.580

17.59 28.89

7.62 4.419

11.48 11.06

Sp (m)

1.25 0.306

1.14 (.075

1.03 0.333

1.22 0.488

Sv (m)

2.55 1.036

3.08 1.818

2.57 0.675

2.94 1.432

Sz (m)

3.79 1.093

4.27 2.351

3.60 0.674

4.14 1.451

g/m

g/m

log t (min)

log t (min)

COF controlled by a tribofilm or by the ring wear

2.2.3 Bore and ring materials friction and wear base line

2.2.4 Bore and ring materials friction and wearGraphite morphology + (residual carbide, martensite)

COF

t (s)

Paulo Ogata

Shorter running in periodCOF maleable iron in the boton range

Lower wear after 1hr.Same avg COF after 1 hr

COF Ring x (grey or) maleable iron – 5 tests each.

F: 50N , 20HzStroke: 2.5 mmT: 25 COil: PAOFully flodedSurface: Milled

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2.2.5 Bore and ring materials friction and wearDeep etched cast iron

Deep etch after milling

Deep etch after polishing

Lazer interferomety. Deep etched after polishing gray cast iron.

COF

t (s)

Raquel Camponucci

Shorter running in periodCOF values milled + deep etch in the boton rangeCOF polished + deep etched lower than COF range in the running in period

F: 50N , 20HzStroke: 2.5 mmT: 25 COil: PAOSurface: Milledt: 6, 60, 600 min

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2.2.6 additives + nano particles

A MoDTC + PAO + EsterCOF increases with F

B Stearic acid + PAO + EsterCOF decreases with F

C NanoMag – Stearic + PAOCOF decreases with F

D Frunkim Isotherm ~ A & B

Boundary lubrication COF models

47Eduardo Trindade - Ane Rovani - André Zuin

Some remarks 1/4

- MINIMIZE RUNNING IN (LESS DEBRIS)- RESIST TO PRESSURE AND TEMPERATURES

Mixed Lubrication

2014 Results. Running in reduction

2014 Results. COF decreases with F

New engine more boudary and mixed lube regimes

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Some remarks 2/4

- LOWER THE COF ALL LUBRICATION REGIMES

2014 Results. PAO, PAO Nano MAG, 5W30, maleable iron. COF 0,15 – 0,10

Mixed Lubrication

2014 Results. Texture, deep etch

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Some remarks – Chalenges 3/4 - COF 0,05 – 0,02-COF lower than 0,01

Mixed Lubrication

Tribl Int. 65 (2013) 28-36 50

Some remarks – Chalenges 4/4- COF 0,05 – 0,02-COF lower than 0,01

Mixed Lubrication

v incresev decrease

COF

COF

t min 51

+ water

Tribological challenges in flex fuel engines.

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Transcript of Tribological challenges in flex fuel engines.