UNCLAS: Dist A. Approved for public release

IMPACT OF FRICTION REDUCTION 

TECHNOLOGIES ON FUEL ECONOMY FOR 

GROUND VEHICLES

G. R. Fenske, R. A. Erck, O. O. Ajayi, A. Masoner, 

and A. S. Comfort

13 August 2009 UNCLAS: Dist A. Approved for public release
Report Documentation Page Form Approved

OMB No. 0704-0188

Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and

maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information,

including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington

VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it

does not display a currently valid OMB control number.

1. REPORT DATE

08 AUG 2009

2. REPORT TYPE

N/A

3. DATES COVERED

 - 

4. TITLE AND SUBTITLE

Impact of Friction Reduction Technologies on Fuel Economy for

Ground Vehicles

5a. CONTRACT NUMBER

5b. GRANT NUMBER

5c. PROGRAM ELEMENT NUMBER

6. AUTHOR(S)

G.R. Fenske; R.A. Erck; O.O. Ajayi; A. Masoner’ A.S. Confort

5d. PROJECT NUMBER

5e. TASK NUMBER

5f. WORK UNIT NUMBER

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)

US Army RDECOM-TARDEC 6501 E 11 Mile Rd Warren, MI 

48397-5000

8. PERFORMING ORGANIZATION REPORT 

NUMBER

20144 RC

9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR’S ACRONYM(S)

TACOM/TARDEC

11. SPONSOR/MONITOR’S REPORT 

NUMBER(S)

20144 RC

12. DISTRIBUTION/AVAILABILITY STATEMENT

Approved for public release, distribution unlimited

13. SUPPLEMENTARY NOTES

Presented at NDIAs Ground Vehicle Systems Engineering and Technology Symposium (GVSETS), 17 22

August 2009,Troy, Michigan, USA, The original document contains color images.

14. ABSTRACT

15. SUBJECT TERMS

16. SECURITY CLASSIFICATION OF: 17. LIMITATION

OF ABSTRACT

SAR

18. NUMBER

OF PAGES

21

19a. NAME OF

RESPONSIBLE PERSON

a. REPORT

unclassified

b. ABSTRACT

unclassified

c. THIS PAGE

unclassified

Standard Form 298 (Rev. 8-98)

Prescribed by ANSI Std Z39-18 
UNCLAS: Dist A. Approved for public release

Outline of Presentation

• Overview of Petroleum Consumption - How Much Do We 

Actually Use

• How Does Tribology (Friction and Wear) Fit Into the 

Equation

– If we get rid of all friction, how big of an impact will a ‘frictionless’ 

engine have on petroleum consumption

– If We reduce friction by x%, how much petroleum can we save?

• What’s the Difference Between Commercial and Military 

Applications

– Driving/Operational Driving Schedules

• What’s Being Done (Research) to Reduce Petroleum 

Consumption, or, Improve Energy Security?

13 August 2009 2
UNCLAS: Dist A. Approved for public release

World Energy Production & Consumption 

1 QUAD/yr ~ 0.5 MBBL/day

• World Energy Production (All Sources) 460 Quads (2005)

• US Energy Production (All Sources) 72 Quads (2007)

– 16% of World Production

• World Energy Consumption (all sectors) 463 Quads (2005)

• US Energy Consumption (all sectors) 101 Quads (2007)

– 22% of World Consumption

• World Petroleum Production 81 MBBL/day (2007)

• US Petroleum Production 6.9 MBBL/day (2007)

– <9% of World Production

• World Petroleum Consumption (all uses) 85 MBBL/day (2006)

• US Petroleum Consumption 21 MBBL/day (2006)

– 25% of World Consumption

http://www.eia.doe.gov/emeu/aer/pdf/aer.pdf
UNCLAS: Dist A. Approved for public release

US Energy Flow (2007)

102 QUADs

• QUADrillion (1015) BTUs per year

• 1 QUAD equivalent to 0.47 million bbl crude oil/day

– 39.82 QUAD Petroleum - 18 million bbl/day

http://www.eia.doe.gov/emeu/aer/pdf/pages/sec1_3.pdf

13.7 Mbbl/day
UNCLAS: Dist A. Approved for public release

Majority of Oil Consumed by ON-ROAD 

Vehicles - 10 to 11 MBBL/Day for Cars, Light 

Trucks, and Heavy Trucks
UNCLAS: Dist A. Approved for public release

Federal Government is Largest 

Single Consumer of Petroleum

• In FY 2004; federal agencies accounted for 1.9 % of US 

petroleum consumption 

– DoD - 93% of US Government Consumption

– DoD - equivalent to 360,000 bbl/day

• Cost of Petroleum 

– Commercial/civilian (large volume/low price)

• $50 to $ 150/bbl

• $2.00-$4.50/gal at pump

– Military (lower volume / high price)

• $50 to $150/bbl

• $20-$30/gal delivered (aircraft)

• $100-$600/gal delivered in field (ground vehicles)

13 August 2009 6
UNCLAS: Dist A. Approved for public release

How Much of the 10-11 MBBL/day of Petroleum Used 

for On-Road Vehicles is Lost to Friction? - More 

Energy is Lost to Friction Than is Delivered to the 

Wheels

• Energy Map- Passenger Vehicle EPA Cycle

– Roughly 10% of energy input consumed by 

friction

– ≈1 million barrels/day lost to friction in 

transportation

Energy In

100%

Indicated HP

35%

Brake HP

23%

At Wheels

9.5%

Exhaust

35%

Engine Cooling

30%

Other Engine Friction

0.4%

Piston Assembly

2.8%

Valve Train

1.3%

Bearings

1.0%

Seals

0.5%

Air Pumping

6%

Others

1.6%

Transmission

2.0%

Braking

2.0%

Coast/Idle

4.0%

Axle

1.6%

Accessories

Oil Pump - 0.5%

Air Pump – 0.1%

Water Pump - 0.1%

Fuel Pump - 0.1%

Power Steering – 0.5%

Cooling Fan – 0.5%

Alternator – 0.5%

Viscous Loss – 1.35%

Friction Forces – 0.95%

Blowby – 0.5% Aero Drag

4.0%

Tires

5.5%

15% of IMEP

(Indicated Mean Effective 

Pressure – HP normalized 

to engine displacement)
UNCLAS: Dist A. Approved for public release

500

700

900

1100

1300

1500

1700

1900

0 500 1000 1500 2000

Load/IMEP (kPa)

Speed (rpm)

1 (52%)

2 (3%)

3 (4%)

4 (15%) 5 (8%)

6 (6%) 7 (8%) 8 (5%)

Weighting factor

Detailed Studies of Heavy-Truck Friction Losses Based 

on Mechanistic Models of Boundary and Hydrodynamic 

Friction Predicted Impact of Lowering Boundary 

Friction and Lubricant Viscosity on Fuel Economy 

Rocker bushing *

Rocker tip to valve *

Pushrod to rocker interface *

Piston pin bearing *

Rings *

Piston Skirt *

Cam - follower interface *

Cam bearings *

Follower - pushrod interface *

Timing drive

Journal bearings

Crankshaft windage

Oil Pump

Fuel injection system

Crankshaft main bearings

Main seals *

* interface considered in current study

• FMEP calculated at 8 different modes and 

weighted to predict effect on fuel consumption 

for a HD driving cycle

FCSF = 

(Fuel Consumption Scaling Factor)

IMEP + ΔFMEP

IMEP
UNCLAS: Dist A. Approved for public release

Role of Boundary and Hydrodynamic 

Lubrication Regimes

- Tribological System

• Different regimes of 

lubrication depending on the 

degree of contact between 

sliding surfaces

• Boundary lubrication 

characterized by solid-solid 

contact – asperities of mating 

surfaces in contact with one 

another

• Contrast boundary lubrication 

with full-film lubrication in 

which mating surfaces are 

separated by a film.

• In between, mixed lubrication 

occurs.

Boundary Lubrication

Mixed

Lubrication

Full Film

Lubrication

Viscosity * Speed/Load

Friction Coefficient
UNCLAS: Dist A. Approved for public release

Boundary and Hydrodynamic Friction: 

Model Impact on FMEP and Wear 

Severity

• Total FMEP is the sum of the Asperity friction and the hydrodynamic friction

– Boundary FMEP decreases with increasing lubricant viscosity – shifting from BL to ML regime

– Hydrodynamic FMEP increases with increasing viscosity

Piston FMEP versus Viscosity Grade

0

5

10

15

20

25

10 20 30 40 50

SAE Viscosity Grade

FMEP (kPa)

No Treatment Total

Est 30% Reduction Total

Est 60% Reduction Total

90% Reduction Total

Hydrodynamic

Asperity / No Treatment

Asperity / Est 30%

Asperity / Est 60%

Asperity / 90%

Normalized Piston - Liner Contact Severity 

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

0 10 20 30 40 50

SAE Viscosity Grade

Relative Wear Load

Viscous

FMEP

Asperity

FMEP
UNCLAS: Dist A. Approved for public release

Modeling the Impact of Friction on Fuel 

Efficiency and Identifying Critical 

Components - HD Diesel

• Prediction/Modeling of Fuel 

Savings

– Systematic studies on the effect of 

boundary friction and oil viscosity on fuel 

efficiency

– Up to 1.3 % fuel economy improvement 

by low friction additives and/or coatings

– 3-4% fuel economy improvement by 

reducing boundary friction and reducing oil 

viscosity

– Additional 2-4% fuel economy gains in 

transmission and differential/axle

Piston Rings and Skirt: Impact of Reduced Asperity Friction on Fuel Savings (gals) 

@ 1000 hrs Operation

-100

-50

0

50

100

150

200

250

300

0 10 20 30 40 50 60

SAE Lubricant Grade

Gallons of Fuel Saved per 1000 

Hours Operation

Baseline Friction - 0% Reduction

30% Asperity Friction Reduction

60% Asperity Friction Reduction

90% Asperity Friction Reduction

SAE Viscosity Grade

-6%

-4%

-2%

0%

2%

4%

0 10 20 30 40 50

Predicted Change in Fuel Consumption

0% Reduction

30% Reduction

60% Reduction

90% Reduction

Baseline

SAE 40
UNCLAS: Dist A. Approved for public release

‘HOWEVER, ... Your mileage 

may vary...’

• Standard disclaimer ‘Your mileage may vary’ on EPA mileage 

estimates is used for a very valid reason, and this is especially true 

for estimating the impact of friction on the fuel efficiency of military 

vehicles

– Parasitic frictional losses depend strongly on engine conditions 

(load and speed). Highest losses (percentage of IMEP) occur at 

low speed, low load conditions

13 August 2009 12

• There are significant differences between 

civilian on-road driving cycles and military 

driving cycles

• High percentage of time spent near 

idle

• Off-road (high load) and low speed 

conditions
UNCLAS: Dist A. Approved for public release

Military Driving Cycle Significantly 

Different from On-Road Civilian Cycle

• Wheeled Ground Vehicle (80-85 % idle; 25 mph avg.)

13 August 2009 13

Patterns of Use M998 Baseline M998 w Armor; w A/C

Time 

(hr)

Distance 

(mi)

<speed> 

mph

Burn Rate 

(gal/hr)

mpg Consumed 

(gal)

Burn Rate 

(gal/hr)

mpg Consumed 

(gal)

Total Mission 24 100 25/0 1.4 6.8 32.6 1.9 5.3 46.0

Primary Rds 0.6 20 33 3.3 10.6 1.9 4.2 8.4 2.4

Secondary Rds 1.7 50 30 3.4 8.8 5.7 4.2 7.2 7.0

Trails 0.8 20 25 4.8 5.2 3.9 6.5 3.8 5.2

Cross-Country 1 10 10 3.2 3.1 3.2 4.2 2.4 4.2

Idle 20 - - 0.9 - 18.0 1.4 - 27.2

2 (3%)

3 (4%)

4 (15%) 5 (8%)

6 (6%) 7 (8%) 8 (5%)

500

900

1300

1700

2100

0 500 1000 1500 2000

Speed (rpm)

Load/IMEP (kPa)

Mode 1 (52%)

MITRE Corporation, Report No. JSR-06-135

• On-Road FTP

• Low idle

• High speed

• On-road (low load)
UNCLAS: Dist A. Approved for public release

Impact of Driving Cycle on the 

Effectiveness of Low-Friction 

Technologies to Improve Fuel 

Efficiency

• Low friction technologies at high Idle, low speed, high 

load conditions (lower right) have greater impact on fuel 

consumption

13 August 2009 14

On-Road FTP 70 % Idle, Mode 2 & 3
UNCLAS: Dist A. Approved for public release

Friction Reduction Technologies Have 

Greater Impact on Fuel Economy at 

High Idle Conditions

• Impact of Idle on the fuel consumption for a 90 % 

reduction in boundary friction

13 August 2009 15
UNCLAS: Dist A. Approved for public release

Fuel Efficiency - Summary

• 13-14 Mbbl/day consumed for transportation

• US military consumes 2% - approx 360,000 bbl/day

– Cost of fuel delivered to theatre is high ($100-$600/gal)

• Rule-of-Thumb

– Approx 10% of fuel consumed (on-road) is lost to engine friction

– Another 5% lost to driveline friction

• Driving cycle significantly impacts the efficacy of lowfriction technologies to improve fuel economy

– High idle modes are impacted more by low-friction technologies 

13 August 2009 16
UNCLAS: Dist A. Approved for public release

Additional Comments – Viscosity 

& Durability

• Use of low-viscosity lubricants, while effective in reducing 

fuel consumption, will increase contact severity

– Need for improved wear-resistant materials, coatings and antiwear additives

13 August 2009 17
UNCLAS: Dist A. Approved for public release

Additional Comment – Low Friction 

Technologies – Can We Achieve 30, 

60, or 90 % Reduction in Friction?

• Multiple approaches to reduce friction – materials, 

coatings, additives – requires lab, component, and 

system testing.

13 August 2009 18

ring/liner

skirt/liner
UNCLAS: Dist A. Approved for public release

Reliability Under Severe Tribological 

Environments Critical to Accomplishing 

Military Missions

• Application of advanced lab techniques to characterize 

scuffing phenomena and investigate the impact of 

additives on delaying the onset of scuffing.

13 August 2009 19

Ring

Block

Oil Chamber
UNCLAS: Dist A. Approved for public release

Impact of Additives on Scuffing

• Impact of additives and additive concentration on the 

scuffing load of formulated mil-spec 15W/40 oil, and 

unformulated basefluid

13 August 2009 20
UNCLAS: Dist A. Approved for public release

Conclusions

• Parasitic friction mechanisms (oil shearing and metal-to-metal asperity friction) consume 

approximately 10% of fuel used in transportation. Another 5% is consumed by drivetrain friction.

• The losses can be significantly greater for vehicle operating cycles that involve long periods of 

idle, where power is required for hotel power.

• Application of low-friction boundary-film technologies will lower fuel consumption by 1% for an onhighway commercial truck. Greater fuel savings (up to 2%) can be realized for high-idle driving 

cycles that involve off-road conditions.

• The application of low-friction technologies that lower friction in the boundary-lubrication regime 

(Stribeck curve) enables the use of low-viscosity fluids resulting in potential fuel savings up to 3-

4% for commercial driving cycles – provided suitable low-friction technologies are available.

• While low-viscosity lubricants are beneficial in reducing parasitic friction losses, caution must be 

exercised to offset the increased contact severity and potential durability/reliability issues 

associated with increased contact loads that occur with low-viscosity fluids.

• Potential solutions to improve fuel economy, such as lubricant additives and low-friction 

materials/coatings, have been identified in lab studies, and need further effort to implement them 

industrially.

• The use of advanced additives in formulated mil-spec lubricants has been observed to increase 

the scuffing resistance in lab-based tests and may represent a potential solution to enhancing the 

survivability of ground vehicles under extreme tribological environments.

• High idle drive cycles incur the greatest amount of parasitic friction losses and are 

influenced more by low-friction technologies

13 August 2009 21