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 releaseReport 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 r eviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden es timate 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 pen alty 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 Z39-18UNCLAS: 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 2UNCLAS: 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.pdfUNCLAS: Dist A. Approved for public release 

# US Energy Flow (2007) 102 QUADs



# • QUADrillion (10 15 

# ) 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/dayUNCLAS: 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 TrucksUNCLAS: 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 6UNCLAS: 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 + Δ FMEP IMEPUNCLAS: 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/LoadFriction CoefficientUNCLAS: 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 GradeFMEP (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 GradeRelative Wear Load

Viscous

FMEP Asperity

FMEPUNCLAS: 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 GradeGallons of Fuel Saved per 1000Hours 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 50Predicted Change in Fuel Consumption 0% Reduction 30% Reduction 60% Reduction 90% Reduction 

## Baseline SAE 40UNCLAS: 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 conditionsUNCLAS: 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 2000Speed (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 & 3UNCLAS: 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 15UNCLAS: 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 low friction technologies to improve fuel economy

– High idle modes are impacted more by low - friction technologies 13 August 2009 16UNCLAS: 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 anti wear additives

13 August 2009 17UNCLAS: 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/linerUNCLAS: 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 C hamberUNCLAS: 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 20UNCLAS: 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 on highway 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