Afton Chemical presents Influence of Film Structure on Vane Pump Protection

Influence of Film Structure on Vane Pump Protection

STLE May 21, 2019 Xinggao Fang, Mark Devlin, Philippe Ezanno

AftonChemical.com

Outline Basics of vane pump test: ASTM D7043 Bench screener and mechanism of vane pump wear Performance of and tribo-films from simplified fluids

Experimental fluid examples

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Advancement in transmission technologies Hardwares are exposed to more severe stress Viscosity of transmission oils trends down Additives are required to provide balanced protection Gear scuffing resistance: failure load stage (A10/16.6R/90) ≥ 8  Vane pump protection (V104C): weight loss < 10mg  Superior copper protection against leaching 

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Vane pump test ASTM D7043, fluid wear characteristics in constant volume vane pump Complicated in comparison to bench tools such high frequency reciprocating rig (HFRR)

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Modified D7043 (V104C) V104C is required by major OEMs 

Pressure: 6.9 MPa (1000 psi)  Speed: 1200 rpm  Oil temperature: 80 C  100 hours unless specified  Weight loss(vanes + cam) <10 mg

This work uses 15 hour version of the test

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HFRR wear as a screener for V104C? HFRR condition: 4N, 50Hz, 2mm, 80C, 60min Wear scar is the worn area at the center of the wear track

Tribology

V104C

HFRR-wear

Sliding speed (m/s)

3.6-4.2

0-0.4

Temperature ( oC)

80

80

Contact stress (GPa)

1.1

1.03

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HFRR wear scar is not predictive for V104C 800

700

694

V104C weight loss, mg

600

500

400

300

200

179

100

0 0

200

1.3

400

600

0.6

800

33.7 1000

HFRR wear scar,

1200

1400

1600

1800

Âľm2

Single component oils, KV100=4.7 AftonChemical.com Confidential and Proprietary - not to be copied, shared, or reproduced in any media without the express written permission of Afton Chemical Corporation. 2019 Š Afton Chemical Corporation, All Rights Reserved

HFRR friction not predictive for V104C 65.3

70

60

V104C weight loss, mg

50

40

34 28.5

30

20

10

1.4

0.8 0 0.080 -10

0.100

0.120

-1.1

0.140

-0.9 0.160

0.180

0.200

HFRR coefficient of friction

HFRR friction (4N, 20Hz, 1mm, 3 minutes) at 100C Single component oils AftonChemical.com Confidential and Proprietary - not to be copied, shared, or reproduced in any media without the express written permission of Afton Chemical Corporation. 2019 Š Afton Chemical Corporation, All Rights Reserved

Mechanism of V104C failure Fluids

weight loss, mg Calculated Fe ppm*

measured Fe ppm

A

515

47

44

B

462

42

41

C

781

72

73

D

443

41

45

* Calculated Fe (ppm) = weight loss/(3.5gal*3.78L/gal*0.82kg/L)

Fluids contain typical ATF anti-wear components The data suggest a “molecular corrosion” mechanism AftonChemical.com Confidential and Proprietary - not to be copied, shared, or reproduced in any media without the express written permission of Afton Chemical Corporation. 2019 © Afton Chemical Corporation, All Rights Reserved

Effect of organic friction modifiers Fluids

KV100, cSt

Weight loss, mg

High viscosity base oil

8.34

59.1

Base oil + GMO, 1%

4.66

65.3

Base oil + FM1, 1%

4.72

1.4

Base oil + FM2, 1%

4.57

0.0

GMO: glycerol mono oleate

High viscosity alone is not sufficient to provide pump protection Experimental friction modifiers could provide pump protection without the need of conventional P and S anti-wear additives AftonChemical.com Confidential and Proprietary - not to be copied, shared, or reproduced in any media without the express written permission of Afton Chemical Corporation. 2019 Š Afton Chemical Corporation, All Rights Reserved

Effect of components on vane pump protection Both Fluids E and F contain same active sulfur. E contains dispersant capped phosphorus component, F with additional common phosphorus component Fluid-E

Fluid-F

P, ppm in oil

306

591

S, ppm in oil

1960

2203

KV100, cSt

5.08

5.37

V104C loss, mg

544

0.5

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Effect of components on vane pump protection Fluids G and H have similar elemental compositions.

Additives are from commonly used commercial components Fluid G

Fluid H

P, ppm in oil

259

278

S, ppm in oil

1803

1747

KV100, cSt

4.87

5.11

V104C loss, mg

267

1.2

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SEM pictures of end of test vanes SEM pictures of vanes, top view

267mg loss

1.2mg loss

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Tribofilm on vane surface from Fluid G EDX analysis in the contact zone (average of 5 spots)

Top of vane contact zone

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Effect of tribofilm on vane pump protection Fluid G

Fluid H

P, ppm in oil

259

278

S, ppm in oil

1803

1747

V104C loss, mg

267

1.2

P, wt% on vane

0.37

0.59

S, wt% on vane

9.07

<0.1

Proper phosphorus in tribofilm prevents the attack of vanes by active sulfur, thus gives protection to vane pump

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Balanced hardware protection Vane pump protection (V104C): <10 mg loss Gear scuffing resistance: failure load stage (A10/16.6R/90) â&#x2030;Ľ 8 Yellow metal compatibility: ASTM D130 durability

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Formulated experimental fluids Additives

C1

C2

Fluid-1

Fluid-2

P, ppm in oil

286

380

181

278

S, ppm in oil

1200

725

542

1747

KV100, cSt

7.44

5.63

5.3

5.11

V104C loss, mg

0.5

0.6

0

1.2

FLS (A10/16.6R/90)

5

5

8

10

Cu(D130 14days 150C) ppm

178

2646

90

33

Conventional transmission fluids C1 and C2 compromise between the trade-off of gear and vane pump protection Experimental fluids break the trade-off paradigm and provide overall balanced protection AftonChemical.com Confidential and Proprietary - not to be copied, shared, or reproduced in any media without the express written permission of Afton Chemical Corporation. 2019 Š Afton Chemical Corporation, All Rights Reserved

Summary Experimental organic friction modifiers can protect vane pump in low viscosity oil without traditional anti-wear additives Vane pump fails in ATFs by molecular level corrosive wear Phosphorus in the tribofilm not in the oil provides pump protection Experimental fluids are able to provide balanced hardware protection Gear scuffing resistance: failure load stage (A10/16.6R/90) ≥ 8  Vane pump protection (V104C): weight loss < 10mg  Superior copper protection against leaching 

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Acknowledgment Richard White of University of Virginia for SEM and EDX measurement

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