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/bore- valve/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
3 . TRIBOFLEX Structure
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
3 . TRIBOFLEX Structure
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
3 . TRIBOFLEX Structure
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
2. Selected topics on engine tribology
- 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
2. Selected topics on engine tribology
26
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)
2.1 CHARACTERIZATION – RING - BORE
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
Dinécio Santos Filho / Hélio Goldenstein
2.1 CHARACTERIZATION – RING - BORE
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.
Dinécio Santos Filho / Hélio Goldenstein
TDC BDCMidSummit and core wear 28
2.1 CHARACTERIZATION – RING - BORENew E 20 E 100
Ring wear more intense in the ethanol engine test
Dinécio Santos Filho / Hélio Goldenstein
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 !
2.2.1 How are we measuring?
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)
2.2.1 How are we measuring?
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
2.2.2 Effect of TOPOGRAPHY Anisotropy
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
2.2.2 Effect of TOPOGRAPHY Anisotropy
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)
2.2.2 Effect of TOPOGRAPHY Anisotropy
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
42
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
45
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
46
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
48
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
49
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