Low-Friction Engine Surface Finishing: Insights from ... · Prof. EL MANSORI Monday, May 4th, 2015...

Prof. EL MANSORI Monday, May 4th, 2015

Low-Friction Engine Surface Finishing: Insights from Tribology and Manufacturing

Prof. Mohamed EL MANSORI

[email protected]

Mechanics, Surfaces & Material Processing Laboratory

www.msmp.eu

Arts et Métiers ParisTech

France

http://www.msmp.eu/


CONTENTS

Introduction

Process-Surface-Functionality (PSF) methodology

Industrial surface textures

Low friction innovative textures

Conclusion & perspectives


Materials

Material behavior, Damage Mechanics,

Tribological behavior, etc.

Products

Residual stress, Surface finish,

Microstructures, Fatigue, etc.

Processes

Micro-joining Machining, Additive

manufacturing, Coating etc.

☄ Approach : Through-process Modeling Vision

☄ Methodology :

Concept of Multiscale Process Signature:

Manufacture by function

EL Mansori et al., On concept of process signature analysis of multistage

surface formation, Surface Engineering 26 (3), 2010, pp.216-223

We are seeking the links between :

Philosophy in Current Multiscale Manufacturing Research


Nano- scale

< 1µm

Macro

>10 mm WAVELENGTHS RANGE

Wide range of measurement lengths scale

Atomic Force Microscope

Dimension Edge (Bruker)

Interferometer

Wyko NT3300 (Veeco)

Tactile profilometer

(SurfaScan)

Form measurement

MarForm (Mahr)

Nanosignature : Surface features at the resolution of the atomic scale (0,1-

100nm)

Scale of surface features


Manufactured surfaces in Functionalised Auto Engine Bores

METHODOLOGY INDUSTRIAL TEXTURES INNOVATIVE TEXTURES CONCLUSIONS INTRODUCTION

6

Sao Paulo - Brazil 04/05/2015

Euro 6b, Sept. 1st 2015

Honed surface

texture

Cylinder liner

Piston

Top compression ring

Intermediate ring

Oil control ring

Ecological and economic

context

Mechanical losses in a combustion

engine

Holmberg et al., 2011

INTRODUCTION

General trends of engine functional

performances

Years

Fu

ncti

on

nali

ty

Industrial context


7

Ring Cylinder surface

Communicating grooves

Piston motion

Valve Stems

Re-aspiration / Decantation

Pistons / Rings / Cylinder

Rings

Cylinder

Piston Oil film

Honed surface

The main source of oil consumption

The running-in duration (wear resistance)

The lubrication between the piston rings

The oil retention capacity (HL & BL)

The friction losses

…

Functions of Cylinder Surface of A Combustion Engine ??


8


Abrasive honing

Schmid et al, 2009

Tomanik et al, 2008

Dobrica, Fillon, 2008

Goeldel et al, 2012

Sabri et al, 2011 Plateau-honed surface Slide-honed surface

Groove width/depth ratio :

λD ~ 9-27

Which process generates a surface with the best functional performances ?

1mm 1mm

Laser texturing

Tomanik, 2008

Etsion, Sher, 2009

Schmid et al, 2009

Laser surface texturing


λD ~ 5 – 300 (generally around 20)

Laser honing

Mechanical honing is more interesting in terms of manufacturing costs

INTRODUCTION

Thermal spray coating

Bobzin et al., 2008

Howell-Smith, 2014


λD ~ 2

Other techniques

UV Laser

• UV Laser

• Etching

• Brush honing, etc.

Schmid et al, 2009

Petterson, Jacobson, 2007

Suh et al., 2010


λD ~ 20-80 for UV laser

λD ~ 10-200 for etching


9


Which process generates a surface with the best functional performances ?

Industrial abrasive honing processes for lamellar cast-iron liner

INTRODUCTION

3D topography

2D roughness profile θ Ra Rpk/Rvk λD

Slide Honing (SH) Dimkowski et al, 2012 Tomanik, 2008 Haasis, Weigmann, 1999

40-50 ~0,2 0,75 ~ 17-27

Plateau Honing (PH) Goeldel et al, 2012 Sabri et al, 2011 Pawlus et al,, 2009

40-50 ~0,4 0,55 ~ 9-19

Helical Slide Honing (HSH) Schmid et al, 2009 Mezghani et al, 2012 Haasis, Weigmann, 1999

120-140 ~0,25 ~0,7 ~ 11-18

(µm)

(mm)

(µm)

(mm)

(µm)

(mm)


10


Problem ?

Which honing process generates the cross-hatch texture of

cylinder surface with the best functional performances ?

INTRODUCTION

Plateau-honed

Slide-honed

Helical-slide-honed

Surfaces textures Honing process

Process variables

Axial velocity

Rotation speed

Expansion speed

Contact pressure

Honing duration, etc.

Honing Head

Functional performances

Friction losses

Oil consumption

Wear

Sealing

Load admission, etc.

Functionality

Engine cycle


11


The methodology is based on:

Honed surface production at the industrial scale

Advanced surface characterization methods

Numerical and experimental RPC contact analysis


METHODOLOGY

Instrumented

honing experiments

RPC contact

analysis

Um

h

Ring P

Honed surface

of cylinder liner

Fu

nctio

nal p

erfo

rman

ces

Numerical simulation

Experimental validation

(tribometer)

3D analysis

Multiscale approach

Morphological approach

Surface

characterization

Op

era

tin

g c

on

dit

ion

s

INTRODUCTION


12


Va Va

Vr tan(α/2)=Va/Vr

Vr α

Vexp

Honed surface generation on the

industrial scale

Honing process

METHODOLOGY

Rough honing

Finish honing

Plateau honing

Plateau honing

Slide honing

Turning operation

Rough honing

Finish honing

Superfinish honing

Helical slide

honing

Turning operation


13


Honed surface production at the industrial scale

METHODOLOGY

Grit size

Expansion pressure

Honing kinematics

3rd stage honing cycle

Groove width

Groove depth

Groove cross hatch-angle

Smoothness

Plateauness

Honing process Process variables Surface characteristics

Description of honing process variables in terms of pattern characteristics


14


Advanced surface characterization methods

Surface texture

characteristics

Groove depth : Svq

Plateau amplitude:

Spq

Smoothness :

Spq+Svq

Plateauness : Spq/Svq

Anisotropy: Ө°

METHODOLOGY

Functionality

Friction

Lubrication

Morphological decomposition

into plateau and valley

Plateau

component Valley

component

Spq Svq


15



TDC MC

rings

Pis

ton

𝐒 =𝛍𝐃 × 𝐯

𝐅𝐍𝐥𝐲

• 𝝁𝑫 : dynamic viscosity

• 𝒗 : sliding velocity

• 𝑭𝑵 : normal load

• 𝒍𝒚 : contact width

METHODOLOGY

Co

eff

icie

nt

of

fric

tio

n

Toward BDC

𝐒

TDC MC

Co

eff

icie

nt

of

fric

tio

n

Toward BDC

rings

Pis

ton


16


Inputs

METHODOLOGY

Sliding speed, U

Normal load, W

3D surface

topography

Viscosity

Contact geometry

Ring-liner numerical transient deterministic model

Reynolds equation

Film thickness equation

),,(),,(2

),,(2

0 TYXZTYXX

HTYXH h

Load balance equation

C

dXdYYXPW ),(

Equations

T

H

X

H

Y

PH

YX

PH

XYX

33

where (Eyring model) )sinh(111

m

m

Ring

W

Surface

u2

u1

P1 P2

P(x,y) h(x,y)


Outputs

Oil film thickness, H

Hydrodynamic

pressure, P

Friction coefficient

W

dxdydxdyC C

ec

f


17


Liner holder

METHODOLOGY

Parameters Values

Engine rotating velocity 50 – 300 rpm

Sliding average velocity 0.14 – 0.8 m/s

Lubricant PW40, viscosity of 0.075 Pa.s at 40°C

Normal force 50 – 200 N

Ring-liner reciprocating tribometer

Ring and ring holder

and liner specimen

Lift table with strain

gauges

Rotating slider crank

mechanism

Electrical motor

Normal force clamping

system

Ring-liner system



18


Liner surface texture

Normal load FN

Engine rotation

velocity

Lubricant

Temperature

Ring

Inputs

Friction coefficient

Worn surface

Outputs

METHODOLOGY

Sommerfeld number :

1.0x10-6 < S < 1.0x10-4 𝑆 =𝜇𝐷 × 𝑣

𝐹𝑁𝑙𝑦

Experimental RPC contact analysis



19


Numerical validation Experimental validation

N. Ren, D. Zhu, W.W. Chen, Y. Liu, Q.J. Wang, A Three-Dimensional Deterministic Model for Rough Surface Line-

Contact EHL Problems, J. Tribol. 131 (2009) 011501

Y. Hu, D. Zhu, A Full Numerical Solution to the Mixed Lubrication in Point Contacts, Trans. of the ASME 122 (2000) 1–9

METHODOLOGY

Numerical and experimental RPC contact analysis : model validation

0

0,05

0,1

0,15

0,2

4E-06 4E-05C

oe

ffic

ien

t o

f fr

icti

on

S

Numerical model

Poly. (Tribometer)Essais tribomètre


20



METHODOLOGY

Instrumented

honing experiments

RPC contact

analysis

Um

h

Ring P

Honed surface

of cylinder liner

Fu

nc

tion

al p

erfo

rman

ces

Numerical simulation

Experimental

(tribometer)

Op

era

tin

g c

on

dit

ion

s

3D analysis

Multiscale approach

Morphological approach

Surface

characterization


Honed surface generation on the industrial scale

Advanced surface characterization



21


PSF Methodology

Surface texture

Process scales Functional scales

Groove width

Groove depth

Anisotropy

Plateauness

Smoothness

Honing Process

METHODOLOGY

Functionality


22


Effect of groove depth and width

INDUSTRIAL TEXTURES

180µm

Vexp

Honing Head

Pc(plateau)

40µm

At finish step

Expansion velocity

Gri

t s

ize

Process variables

Gro

ove

wid

th

Groove depth

Surface topography Friction performances

0.0244

0.0245

0.0245

0.0245

0.0246

0.02

46

0.0247

0.0247

0.0247

0.0248

0.0248

0.025

0.025

0.0252 0.0252

0.0252

0.0254

0.0254

Vexp(µm/s)

d(µ

m)

Coefficient de frottement

2 3 4 5 6 7 840

60

80

100

120

140

160

180

0.0244

0.0246

0.0248

0.025

0.0252

0.0254

Coefficient of friction

Process variables coupling enable to obtain the optimal friction coefficient range

Groove width contributes more on friction reduction than groove depth

METHODOLOGY


23


Mutual effect of groove size and anisotropy

Groove size

Gro

ove

orie

nta

tion

(θ2

)

• Grit size

• Expansion pressure

Kin

em

ati

cs

: V

a a

nd

Vr

Cro

ss

-hatc

h a

ng

le (

°)

Groove depth (µm)

Process variables Surface topography Friction performances

Grit size

Va Va

Vr tan(α/2)=Va/Vr

Vr α

Vexp

θ2

θ1

Direction de glissement

θ2

θ1

Direction de glissement

Sliding direction

θ2

θ1

Sliding direction

θ2

θ1

INDUSTRIAL TEXTURES

Texture with lower groove size (generated with lower expansion pressure)

contributes to reduce friction

θ2 = [30 - 50°] and [120 - 130°] are the best groove orientations

θ2 = [120 - 130°] is less sensitive to groove depth


24


PSF Methodology

Surface texture

Process scales Functional scales

Groove width

Groove depth

Anisotropy

Plateauness

Smoothness

Honing Process

METHODOLOGY

Functionality


25


Effect of plateauness and smoothness

3rd step honing

duration

Expansion pressure

Process variables Surface topography Friction performances

Number of strokes

Pla

tea

u h

on

ing

pre

ss

ure

(B

ar)

5 10 15

3

4

5

6

7

8

9

10

0.02

0.04

0.06

0.08

0.1

0.12

0.14

Zone (2)

Zone (1)

INDUSTRIAL TEXTURES

Zone (2)

Zone (1)

Spq/Svq

Smoothing mechanism (compared to plateauing mechanism) contributes the most

to improve frictional performances


26


Effect of plateauness and smoothness : PH/SH and HSH comparison

3rd step honing

duration

Kinematics

Process variables Friction performances

0,04

0,06

0,08

0,1

0,12

0,14

0,16

1,00E-06 1,00E-05

Co

eff

icie

nt

of

fric

tio

n

S

0 honing strokes5 honing strokes14 honing strokes18 honing strokes

PH

0,04

0,06

0,08

0,1

0,12

0,14

0,16

1,00E-06 1,00E-05

Co

eff

icie

nt

of

fric

tio

n

S

0 honing strokes5 honing strokes10 honing strokes15 honing strokes18 honing strokes

HSH

Fri

cti

on

co

eff

icie

nt Sz=5µm

Film

th

ickn

ess

Sz=5µm

INDUSTRIAL TEXTURES

The final honing step (particularly plateauness) has a lower influence on surface

functionality for HSH surfaces

Lower film thickness obtained with HSH anisotropy

Surface topography

PH/SH

HSH

Sliding direction


27


SPF methodology enabled to define both optimal process variables and

surface patterns for functional improvement

Summary

INDUSTRIAL TEXTURES

It highlighted the most influent surface characteristic on functionality:

o smooth texture with lower groove size; not necessarily plateaued surface

o 130° cross-hatched textures : lower contribution of roughness on friction

reduction

Honing industrial processes :

o set-up tool for the choice of process parameters

o 3rd honing step can be avoided for HSH process


28


Strategy for low-friction textures generation

INNOVATIVE TEXTURES

Generate innovative textures

Circles

Ellipses

Undulatory textures

Sliding direction

Yu et al, 2010

Ren et al., 2007

Wang et al., 2005

Optimize existing textures Dir

ection

de gli

sseme

nt

TDC

BDC

MC

rings

Piston

- Inversion grooves at TDC and BDC

- Homogeneous texture at MC

Optimized trajectory

Mixed textures

Kovalchenko et al, 2011

INDUSTRIAL TEXTURES


29


Innovative textures generation

Designed at Pôle Process Eco², PhD CIFRE thesis, B. Goeldel, 2013

INNOVATIVE TEXTURES

Flexible honing

generator

Work-head carriage (translation)

Rotation motor

Linear engine

Electro-mechanical actuator

Force sensor

Honing tool (rotation only)

Liner part

Honing head

Innovative texture geometry (straight, curvilinear, mixed grooves …)

Open machine for programming (linear, circular interpolations)

« Helical interpolation » (for trajectory optimized textures)


30


Honing experiments

Fu

nctio

nal p

erfo

rman

ces

O

pe

rati

ng

co

nd

itio

ns

Innovative textures: PSF methodology

Friction trials

INNOVATIVE TEXTURES


Honed surface generation

Advanced surface characterization

Experimental RPC contact analysis

Similar 3D roughness (Sk, Spk,Svk)

Different anisotropy

Surface texture


31


Trajectory optimized textures

Conventional Helical Slide Honing (HSH)

Trajectory assisted Helical Slide Honing (HSHAT)

Dir

ect

ion

de

glis

sem

en

tS

lidin

g d

irection

HSH

Dir

ecti

on d

e gl

isse

men

tS

lidin

g d

irection

HSHAT

Direction de glissementSliding direction

BDC


MC


TDC


BDC


MC


TDC

INNOVATIVE TEXTURES Lin

er

heig

ht

(mm

)

80

160

Liner circumference (°) 180 360 0

Lin

er

heig

ht (m

m)

80

160

Liner circumference (°) 180 360 0

Honing trajectory Texture aspect Groove observations

Honing trajectory Texture aspect Groove observations

Deletion of inversion grooves with HSHAT


32


a = 0,24 mm

a = 0,48 mm

Trajectory assisted Helical Slide Honing (HSHAT) D

irec

tio

n d

e gl

isse

men

tS

lidin

g d

irection

HSH

Dir

ecti

on d

e gl

isse

men

tS

lidin

g d

irection

HSHAT

0

0,02

0,04

0,06

0,08

0,1

0,12

0,14

0,16

1,00E-06 1,00E-05

Fric

tio

n c

oef

fici

ent

S

HSH

HSHAT

INNOVATIVE TEXTURES

Friction improvement with HSHAT textures in all the studied lubrication

conditions

Compared textures Comparative Stribeck curves


33



INNOVATIVE TEXTURES


Circles

Ellipses

Undulatory textures

Sliding direction

Yu et al, 2010

Ren et al., 2007

Wang et al., 2005


ection

de gli

sseme

nt

TDC

BDC

MC

rings

Piston




Mixed textures



34



INNOVATIVE TEXTURES


Circles

Ellipses

Undulatory textures

Sliding direction

Yu et al, 2010

Ren et al., 2007

Wang et al., 2005


ection

de gli

sseme

nt

TDC

BDC

MC

rings

Piston




Mixed textures



35


Conclusions

PSF INNOVATIVE METHODOLOGY

Robust link between process and functionality through surface characterization.

CONCLUSIONS INNOVATIVE TEXTURES

Different process optimizations were proposed for HSH process concerning

particularly kinematics and manufacturing costs

SURFACE PATTERNS IMPROVING FRICTIONAL PERFORMANCES

o Lower groove size (abrasive grit size and expansion pressure)

o Smoothness (3rd honing step cycle and expansion pressure)

o Anisotropy (kinematics)

Plateauness has a low contribution on friction reduction compared to smoothness

o A plateau step using a hydraulic expansion for peak clipping is not necessary

Kinematics honing improvements (HSHAT or mixed honing) can be solutions for low

emission engine manufacturing


36


Perspectives

Low-friction innovative textures:

o Mixed 45-130-45 improvements : texturation zones and transition zones

o Circular – elliptical textures : use of longitudinal ellipses

CONCLUSIONS

Fire engine experiments : confirm friction reduction and evaluate oil

consumption, seizure , wear…

Combination of best topography patterns and low-friction anisotropies to

look for the « ideal surface »

Potential transfert to other abrasive process : belt finishing, grinding …


THANK YOU FOR YOUR ATTENTION

Low-Friction Engine Surface Finishing: Insights from ... · Prof. EL MANSORI Monday, May 4th, 2015...

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Transcript of Low-Friction Engine Surface Finishing: Insights from ... · Prof. EL MANSORI Monday, May 4th, 2015...