A New Performance Level for Hydraulic Fluids providing Energy Savings and Emission Reductions

Dr. Hitoshi HamaguchiDr. Eric Fillod

Degussa, RohMax Oil Additives

• Hydraulic Fluid Trends• Viscosity Impact on Performance• Benefits of High VI Oils

• Low Temperature• High Temperature

• Effects of Viscosity on Pump Efficiency• VI Effect• SSI Effect

• Energy Savings by High VI Hydraulic Fluid

• Conclusions

Presentation Outline

“15 percent better fuel efficiency”

Claims for Improved Efficiencyof Mobile Equipment

“Cut your fuel costs by

Up to 30%.”

Claims for Improved Efficiencyof Mobile Equipment

Cranes2%Road Machines

4%Bulldozer5%

Wheel Loader10%

Mini Excavator37%

Off-Road Carrier1% Hydraulic Excavator

41%

Construction Machinery

Production of Earth Moving Equipment in Japan (2003)

Source: Japan ConstructionMachinery ManufacturersAssociation

3m3 Class Wheel LoaderPump Pressure:42 MPa

20t Class HydraulicExcavator

Pump Pressure:35 MPa

Trends in Mobile Pump Pressure

Hydraulic Fluid Trends•Higher Pressures

• Mobile equipment now at 300 bar, moving to 450 bar

•Smaller, Lighter Equipment• Reduced fluid volumes• Less residence time for cooling

•Higher Fluid Operating Temperatures• 80 °C common for mobile equipment• 100+ °C peak temperatures

Improved Fluids are RequiredImproved Fluids are RequiredImproved Fluids are Required

Viscosity Impact onHydraulic Performance

Cavitation

Reduced productivity, Overheating

Optimum Range

Sluggish Operation

Low Mechanical Efficiency

Optimum Range

Poor Flow to Lubricated Areas

High wear, Reduced equipment life1

510

10050

1,000

10,0005,000

500

Visc

osity

, mm

2 /s

Cavitation Sluggish Operations High Wear

Viscosity

Viscosity Impact onHydraulic Performance

Qa = Qn - Ql

Qactual

Qleakage

VolumetricPump

Qnominal

Actual vs. Nominal Flow Rateof Hydraulic Pumps

Qactual

Optimum OperatingOptimum OperatingRangeRange

Overall Efficiency ηOV

Volumetric Efficiency ηVol.

Mechanical Efficiency ηMech.

Viscosity

Effi

cien

cy ηOverall = ηVol. ⋅ ηMech.

Poor volumetric efficiency

High frictional losses

Effect of Viscosityon Pump Performance

High VI Fluids Expandthe Temp. Operating Window

Max

.Vi

scos

ityM

in.

Visc

osity

40 °C

ViscosityViscosity

TemperatureTemperature

TOWTOW low VI oillow VI oil

TOWTOW high VI oilhigh VI oil

I

“In-Service” ViscositySeen by the Pump

Fresh oil viscosityFresh oil viscosity

Base oil viscosityBase oil viscosity

1 to 10 hours

Viscosity

““InIn--serviceservice”” viscosityviscosity

PermanentPermanent

Test time

TemporaryTemporaryUsed oil viscosityUsed oil viscosity

50

60

70

80

90

100

0 0,2 0,4 0,6 0,8 1 1,2

Pressure / (Nom. Flow · "High Shear" Kin. Viscosity)

Vol

umet

ric E

ffici

ency

ηV,

%

Multigrade (HV) OilsMonograde (HM) Oils

Dependence of Efficiencyon “In-Service” Viscosity

Viscosity""PressureQLeak. ⋅= const.

At high temperatures, overall

efficiency depends mainly on

“in-service” viscosity.!

• The Poiseuille Law predicts Leakage:

• Either HTHS viscosity or viscosity after sonic shear (ASTM D 5621) at 100 °C can be used.

Studies in a Komatsu HPV35+35Dual Piston Pump

• Pump is driven by a 22 kW electric motor at 1700 rpm.

• Both monograde (HM) and multigrade (HV) fluids have been evaluated at pressures of 30, 70, 140, 210, 280 and 350 bars.

• Pump inlet temperature from 60 to 100°C

• Flow rate, pressure, torque and rotational speed are measured continuously in order to calculate overall efficiency.

KomatsuHPV35+35

Piston Pump

RohMax PumpTest Stand

Piston Pump

Fluids Tested in the KomatsuHVP35+35 Dual Piston Pump

• Seven mineral oil based fluids, all falling in the ISO 46 viscosity grade.• One monograde (HM) fluid and six different high VI multigrade fluids (HV)• Four fluids blended with PAMA-VI improvers to a VI of 120, 140, 160 and

200, all having a comparable viscosity loss after sonic shear.• The other fluids were blended to meet the same VI of 160 with PAMA-VI

improvers of different levels of shear stability.

VI Improver KV40 KV100 VI KV100 %KV100 LossesISO 46 VI 100 - 44.98 6.81 105 - -ISO 46 VI 120 A 44.69 7.20 122 6.87 4.7ISO 46 VI 140 B 46.08 7.89 141 7.18 8.9ISO 46 VI 160 C 47.75 8.57 158 7.79 9.0ISO 46 VI 200 D 46.01 9.66 202 9.01 6.7ISO 46 VI 160 E 45.99 8.40 160 7.85 6.5ISO 46 VI 160 F 45.16 8.33 162 7.13 14.5

After 40min Sonic Test(ASTM D 5621)Fresh Oil

Dependence of Efficiencyon Viscosity Index

25

30

35

40

100 120 140 160 180 200 220Viscosity Index

Ove

rall

Effi

cien

cy, %

• Efficiencies delivered by different fluids at 350 bars and 100°C were compared.

• Even shear-stable multigrade fluids suffer from shear-thinning.

• The benefits of high VI fluids over-compensate this effect only at VIs above 140.

VII B

VII A

VII CVII D

Performance Claims at High TemperatureVI EffectEffect of Temperature on Efficiency at 350 bars in Komatsu Piston Pump

10090807060

Temperature, °C

9

6

3

0

-3

-6

% G

ain

in G

loba

l Effi

cien

cy

Reference - ISO 46, VI=100

Fresh VI200160140120

A VI of 160 is neededto obtain significantefficiency gainsat high temperature

Efficiency ImprovementsDepend on Shear Stability

• As shown before, shear-stable HV fluids deliver increased pump efficiency.

• In contrast, the fluid formulated with shear-unstable polymer F does not provide high benefits.

VII E VII C VII F

Proposed Performance Level Definition

MEHF Field Test•Caterpillar 318CL Excavator• 1 m3/~2 ton bucket capacity,

medium size in Cat excavator line• Cat 3066T diesel engine

• 125hp/93kW• 2200 rpm max.• 19-23 l/h fuel consumption

• Dual piston pump feeding 3 piston motors, plus boom, stick, and bucket cylinders (345 bar max.)

• Maximum pump flowrates• 95 l/min per pump• 190 l/min to system

• Hydraulic fluid volume• 255 L total in system• 127 L in tank

MEHF Field Test Details•Test Protocol

• Standard earthmoving work protocol, shifting piles of earth 30 m.

• Mild Fall ambient operating temperatures (7-18°C)

• Equivalent time and work output for each fluid, ~1 minute/work cycle

• Tests conducted with engine at full throttle and 90% throttle

• Test Schedule • Day 1 – REO 10W @ 90% Throttle• Day 2 – REO 10W @ Full Throttle• Day 3 – Oil and Filter Change• Day 4 – MEHF @ Full Throttle• Day 5 – MEHF @ Full Throttle• Day 6 – MEHF @ 90% Throttle• Day 7 – Oil Change• Day 8 – REO 10W @ Full Throttle• Day 9 – REO 10W @ 90% Throttle

Work Cycle

1.1. Take full scoop of dirt

2.2. Rotate 180°,travel 30 m

3.3. Dump load4.4. Rotate 180°,

return to start

MEHF Field Test Details

•Test Fluids• Baseline established with standard 10W monograde hydraulic

fluid (REO 10W)• KV 40 = 38.0 cSt, VI = 104

• Comparison made with MEHF 46, VI fresh = 200

• Used Oil After Shear KV 40 = 45.8 cSt, VI = 179

• MEHF formulated with RohMax Dynavis® additive system• VISCOPLEX® 8-219

MEHF Field Test ResultsFuel

Consumed per work cycle,

kg/cycle

OverallImprovement,

Percent

Fuel Consumed per

Hour,kg/hour

Fuel Consumption Improvement,

Percent

Work Cycles per Hour,

Cycles/hour

Work Cycles Improvement,

Percent

REO 10W@

Full Throttle0.364 --- 19.50

15.20

16.80

13.89

53.5 ---

REO 10W@

90% Throttle0.380 ---

---

---

+ 13.8%

40.0 ---

MEHF 46@

Full Throttle0.297 + 18.4% 56.6 + 5.8%

MEHF 46@

90%Throttle0.280 + 26.3% + 8.6% 49.7 + 24.3%

• Hydraulic Fluid Trends• Hydraulic system plays important role in the construction machinery

• Higher pump pressure is employed in modern equipment

• Laboratory Studies• High VI hydraulic fluids formulated with shear-stable viscosity index

improvers provide higher “in-service” viscosity at high operating temperature and lower viscosity at low start-up temperature.

• We have shown that these fluids will thus help to significantly improve pump efficiency at both low and high temperature.

• Based on our studies, a new performance level definition for hydraulic fluids called “Maximum Efficiency Hydraulic Fluid” (MEHF) has been defined.

Summary and Conclusion

• MEHF Field Test

• Test compared OEM recommended 10W (L46-46) monogradewith highly shear stable MEHF 46 fluid

• MEHF 46 shows exceptional results in field testing

• Significantly lower fuel consumption

• Increased work output

• Results fit with lab bench tests and theoretical models

• Overall Conclusion

• MEHF provides energy savings and emission reductions

Summary and Conclusion (cont.)