1. Heavy Duty Fuel Economy
Thakor Kikabhai, Tim Fletcher,
April 2010
A Review of Laboratory Based Fuel Economy Studies
BP Confidential
The following presentation describes some of the work undertaken by HD during recent years to understand FE effects and the influence on FE from the lubricant.

2. Heavy Duty Fuel Economy
The Effect of Lubricants

3. Heavy Duty Fuel Economy – Drivers for Change
Heavy Fuel Economy
Legislation is driving emission standards
No enforced constraint on CO2 emissions (currently)
No fuel economy test within HD specifications (currently)
Fleet operators are motivated to reduce costs
Industry moving to lower viscosity oils
Gareth’s presentation focuses on the legislation in force around the world to ensure compliance to emission standards. Unlike the passenger car area, HD applications are not (currently) constrained by CO2 targets.
Some OEM’s have introduced FE testing (eg/. Volvo D12D FE test for their factory fill oils and MB for their RACE 2012 programme – again a FF oil) but no FE test exists as part of an industry-wide specification.
Consider 1 truck averaging miles per year at 10mpg. A 1% saving in FE equates to 100 gallons diesel (or £500 per truck per year).

4. Heavy Duty Fuel Economy – Effect of Lubricants
Fuel Economy Improvement
Significant testing undertaken by GLT during recent years
Fuel economy improvement mainly explained by viscometrics
Viscosity grade
HTHS (High temperature high shear)
Base oil viscosity
Other factors can influence FE such as DI, polymer type and use of friction modifying components
Internal work has involved the use of a variety of engines including TELCO, MAN, Cummins, Caterpillar, HINO and others specific to OEM’s and proprietary developments.

5. Heavy Duty Fuel Economy – Pangbourne Experience (1)
MAN D20 Engine
MAN D20 (six cylinder HD, 11 litre, Euro IV diesel engine)
Modified European Transient Cycle (ETC) used to evaluate current and new formulations
HTHS and BOV explains majority of FE behaviour
Significant work has been undertaken on a MAN HD engine to evaluate the performance of our top-tier HD oils (namely Elixion) and experimental low viscosity oils. The testing involved the development of a bespoke engine test (centered around a modified ETC protocol at reduced load) that is able to differentiate the performance of oils.

6. Fuel economy - MAN D20 Studies
MAN D20 Engine
Strong correlation with HTHS and weaker correlation with BOV
In general, FE can be predicted from knowledge of the HTHS and BOV of the oil.

7. Fuel economy - MAN D20 Studies
MAN D20 Engine
The influence of viscosity grade on fuel economy:
High FE can be expected from non-typical oils (xW-20’s) that would also involve a departure from the industry standard 3.5cP HTHS limit.

8. Heavy Duty Fuel Economy – Pangbourne Experience (2)
TATA 697TC Engine
Tata 697TC (six cylinder HD, 6 litre, Euro II diesel engine)
In house method based on a nine point speed-load map
Objective is to show 1.5% FEI compared to RX Viscus 15W-40
Work undertaken by Asha Bhaskaran (and later by Simon Edwards) aimed to develop a fuel efficient oil for the Indian HD market.

9. Fuel economy - Tata Studies
TATA 697TC
The influence of viscosity grade on fuel economy:
Two candidates have been identified from the screening work and will be evaluated in further testing (in dynamometer tests in India) and possibly in fleet trials (and in track testing if a suitable fleet cannot be identified).
Again HTHS and BOV are seen as the key parameters and can be used to predict the FE behaviour of these oils.

10. Heavy Duty Fuel Economy – Pangbourne Experience (3)
OM 501 LA
OM 501 LA (six cylinder HD, 11.9 litre, Euro V engine)
Engine used to measure FEI (1% cf 10W-40 reference) – ‘RACE 2012’
Demonstrate benefits of fuel efficient first fill oils for Daimler
HTHS fixed at 3.5cP
Testing at ISP and APL using Daimler protocol
Evaluate effect of components (base oils, friction modifiers, VMs)
Test cycle is WHTC with reference before and after candidate (B5 fuel)
Work by Liz Gupta involved testing oils for MB first fill oils (RACE 2012). New specification is MB and is based on MB performance (E6 – low SAPS limits) and includes two new tests – an oxidation test and an engine test BR 926.

11. Fuel economy - Daimler RACE 2012
OM 501 LA
BOV is a key factor (HTHS constrained at 3.5cP)
Component effects also observed
Formulation 1 2 3 4 5 6 7 8 VM
SV151
H5777
BOV
Mid
High
Low
Yubase 
Yubase + 
PAO
30%
45% FM
FEI% vs 10W-40
0.51
0.52
0.41
0.44
0.71
0.63
0.85
BOV is the key factor. Comparing oils 1 and 3, Yubase + did not give any FE benefit. Comparing 2 and 4, going to high BOV and compensating with PAO also gives no benefit. Comparing 4 and 6, going to low BOV gives significant FE benefit, and FM (oil 7) also improves FE. Final candidate selected was Oil 8, a low BOV oil with H5777 but no FM. Full RACE 2012 testing was completed on this oil. Eventually, we added 5% PAO to get it to pass the OM501LA (same engine, different test) and now have submitted the final formulation to Daimler.

12. Heavy Duty Fuel Economy – Pangbourne Experience (4)
HINO S05C-TI
Hino S05C-TI (four cylinder HD, 5 litre, diesel engine)
Japanese mode transient fuel economy drive cycle used to evaluate current and new formulations
HTHS fixed at 3.00cP
Tests run at 60oC and 90oC, both low and high power
Major influence on FEI is BOV
Polymer choice and friction modifiers seen to affect FEI
Work undertaken by Gareth with HINO as part of ‘strategic accounts project’ aimed to develop a new FE oil for the Japanese market (meeting the DH-2 specification and additional HINO criteria). The requirement was to demonstrate 1% FE benefit cf to a 10W-30 reference oil under specific conditions.

13. Fuel economy - Hino Studies
HINO S05C-TI
Fuel economy as function of power:
Japanese mode test cycle
As HTHS was constrained, experimental work identified BOV as a major influence on the overall FE.
The most effective oil was formulated using Yubase Group III baseoil and included a dispersant polymethacrylate (DPMA) friction modifier.
Average of the results at 60°C and 90°C
gives fuel consumption benefit of 1.76%

14. Heavy Duty Fuel Economy – Pangbourne Experience (5)
Cummins ISB Engine
Cummins ISB (six cylinder HD, 6.7 litre, US 07 diesel engine)
Cummins cycle including motoring, steady state and transient phases
Quantify lubricant effect on engine friction and fuel economy
Lubricants based on CJ-4 technology
HTHS range from 4.2cP – 2.6cP
Component testing of VMs, FMs, BOs
2.9cP, 4.0cSt BOV (5W-30)
Work undertaken by Chris O’Mahony has aimed to develop FE oils using the Cummins ISB engine. (Motoring & Transient) Test cycle proposed by Castrol and adopted, Cummins proposed SS datapoints.

15. Fuel economy - Cummins Studies
Cummins ISB
FE highly dependent on load (and temperature)
BOV and HTHS important factors
BOV = 5.3cSt
BOV = 4.1cSt
Easier to differentiate performance at low loads and lower temperature (see next graph). In this engine, with these oils, BOV appears to be more influential than HTHS for overall FE benefit but both parameters are important.

16. Fuel economy - Cummins Studies
Cummins ISB
FE highly dependent on load (and temperature)
BOV and HTHS important factors
BOV = 5.3cSt
BOV = 4.1cSt
This testing is at the higher temperature (110C cf 50C).

17. Fuel economy - Cummins Studies
Cummins ISB
Results modelled by Cummins (‘Cyber Apps Simulation’)
These slides provide a comparison between data generated on the Cummins ISB engine test bed at BP Pangbourne and data generated using Cummins Cyber Apps simulation software.
The results focus mainly on a 5W-30, 2.9cP, low BOV candidate oil (E0095C/001E) and it’s performance vs. the BP 15W-40, 4.0cP reference oil at low and high temperature.
Engine test bed data is also provided for the current factory fill – Valvoline Premium Blue 15W-40, 4.2cP.

18. Fuel economy - Cummins Studies
Cummins ISB
Formulation has significant influence of FE within the same viscosity profile
SV261 effective at high temp and can be boosted by GMO
SV261
SV261 + GMO
Some components can further improve the FE when HTHS and BOV are constrained.

19. Heavy Duty Fuel Economy – Pangbourne Experience (6)
Caterpillar C13
Caterpillar C13 (six cylinder HD, 12.5 litre, US 07 diesel engine)
Demonstrate benefits of low viscosity oils to Caterpillar
Caterpillar Tier 3 (off highway specification)
Testing at AVL (Graz)
HTHS range from 4.2cP – 2.5cP
Evaluate effect of HTHS and BOV
Test cycle combined 3 transient cycles
World Harmonised Transient Cycle (WHTC) – on highway
Non Road Transient Cycle (NRTC) – off highway
Jwaneng Cycle – in house cycle developed at mine in Botswana
Chris O’Mahony has also examined FE effects in a Caterpillar engine using on-road and off-road test cycles.

20. Fuel economy - Caterpillar Studies
Caterpillar C13
Load (again) the critical influencing factor on lubricant FE
HTHS is dominant compared to BOV (at 90°C)
Again load is important – largest differentiation and improvement (from the reference) is at low loads. In this case HTHS appears to be more dominant cf BOV in the ability to improve an oils FE benefit.

21. Heavy Duty Fuel Economy – Pangbourne Experience (7)
Scania DC13
Scania DC13 engine (six cylinder HD, XPI Euro V diesel engine)
Test method jointly developed between Castrol and Scania
Fuel consumption measured at 8 points in engine map, at 80°C and 100°C
Data is modelled by Scania to produce estimates of FEI in different driving conditions
Objectives are:
0.3% FEI in motorway driving
2% FEI in city driving
vs 15W-40 reference
Work undertaken by May Turner (started by Simon Renouf) to develop a low viscosity fuel economy oil for Scania Euro V XPI engines. XPI is a high pressure common rail injector system offering high performance due to highly controlled injection strategy. Project is a three-way collaboration between Castrol, Scania and Infineum.

22. Fuel economy - Scania studies
Over 40 candidates tested covering:
Viscosity effects (2.0 – 3.5 cP)
VM effects
Friction modifier effects
Chemistry effects
HTHS is dominant influence in this engine
Data at 80°C showed better discrimination and less variability
Greatest discrimination between oils seen at lower speed and load
Scania DC13
Candidate testing very recently completed. Data analysis still being reviewed internally. Clear message already is that HTHS is strongest driver for FE in this engine test. VM change had no effect (engine test v short therefore no opportunity to distinguish between shear stability of VMs). Likely inorganic FM has a positive effect – still being checked. Other formulation effects not discriminated.

23. Fuel economy - Scania studies
Scania DC13
Fuel consumption from each speed-load point was analysed in Scania in-house model
Predictions of FE given for differing drive cycles and vehicle configurations
Excellent correlation seen between Pangbourne fuel consumption measurements and Scania modelled fuel savings

24. Heavy Duty Fuel Economy – Effect of Lubricants
Fuel Economy Improvement can be Predicted
Fuel economy improvement mainly explained by viscometrics
HTHS (High temperature high shear)
Base oil viscosity
Other factors can influence FE such as polymer type and use of friction modifying components
Significant work has been undertaken at Pangbourne by the HD team. HTHS and BOV are important parameters in determining the overall FE performance of an oil.
Customers still have a strong preference for on-road data demonstrating FE benefits under actual driving conditions. This is often difficult to demonstrate because of the need to have large fleets (ideally 30 trucks) to ensure statistically significant effects (that allow for the large variability observed during actual conditions due to driver effects, whether effects, differences in trucks, differences in loads, differences in routes etc). Tim Fletcher has worked to develop protocols and improving the measurement of fuel consumption / engine torque using the proprietary ‘fuel economy meter, FEM’ device.

25. Acknowledgements: Gordon Lamb Angela Keeney Gareth Bracchi Tim Fletcher Asha Bhaskaran Andrew Smith Simon Edwards Chris O’Mahony Liz Gupta May Turner Thank you for your attention

26. Fuel Economy Measurement – Pangbourne Experience
1980
1990
2000
2010
Cummins M11 HD
Full transient cycle – ETC (Hill/Bus/Urban)
HD OEM
Japanese 10&15 mode cycles
FE retention
Chassis Dynamometer and Field Trial Evaluation
HD, PC and MC
Friction Rig: HD&PC
Component and Full Engine
Developed with Torque Flange
Volvo D12A HD
Willans Line
Steady State
MB M111 PC
Gasoline
Simple CEC cycles
Honda CBR600RR MC
Telemetry data of Brands Hatch – perfect reproduction of reality
PC OEM Diesel
Full transient duty cycles
64Hz PC controlled test beds
A/C dyno with Invertor control
ETC cycles
Load mapping
Sequence VIB PC
ASTM Phase 2
Telco 697TC HD
Pseudo transient cycle – dynamic measurements on an absorption dyno
Cummins 5.9L HD
Transient cycles
Regional
Key:
HD: Heavy Duty
PC: Passenger Car
MC: Motorcycle
Internal work has involved the use of a variety of engines including TELCO, MAN, Cummins, Caterpillar, HINO and others specific to OEM’s and proprietary developments.