Engine Oil Requirements for Volkswagen s Light Duty Diesel Engines Dr.-Ing. Sven-Oliver Kossmehl, VOLKSWAGEN AG

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1 Engine Oil Requirements for Volkswagen s Light Duty Diesel Engines Dr.-Ing. Sven-Oliver Kossmehl, VOLKSWAGEN AG

2 Clean Diesel Engines for the North American Market Motivation/Targets: Very low fuel consumption Lowest Exhaust Emissions i Preserve Ressources Increase Comfort Increase Performance Reduce Cost Seite 2

3 Examples of Diesel Engine Features driving the Requirements for the Engine Oil High Engine Efficiency very low Fuel Consumption - Direct Injection - Turbo Charged - High Power Density (~65 kw/l, 150Nm/L typical) Lowest Exhaust Emissions Blue TDI - Particulate Trap - Exhaust Gas Recirculation Seite 3

4 Diesel Power Density against Engine Oil Volume Most powerful 4 Cylinder Diesel Engines for VW Golf for each Model Year shown Seite 4

5 Different Diesel Fuels Different Drain Intervals Major Differences of US Diesel fuel compared to Diesel fuel in the EU: - Cetane number is lower - Higher content of aromatic components - Higher density - Different Biodiesel components used: primarily Soymethylester - Higher Biodiesel content in some places -Oxidation stability bl lower - Risk of more engine oil contamination by fuel & combustion components - Risk of quicker oil degradationd Seite 5

6 Oil Drain Intervals of Volkswagen Diesel Engines LongLife Service in Europe: flexibel up to km/2 years Standard Service in USA: m/1 year Oil Drain Length in Month and km - All samples from Germany 25 Oil Drain Len ngth [Month] Oil Drain Length [km] Seite 6

7 What are the main performance criteria for a Diesel engine oil for Volkswagen passenger cars? Criteria Piston cleanliness Ring sticking DPF blocking Main Driver Piston temperature (310 C and more) High specific load Oil consumption Wear Oil contamination by fuel Critical fuel components, high sulfur fuels Acidification df & Corrosion High ash content of the oil Long drain interval Seite 7

8 High Piston Cleanliness and prevent Ring Sticking Test method: VW PV 1452 (TDI test) 1,9 liter 81 kw TDI engine used - Piston cleanliness measured acc. to DIN has to be equal or better than the reference oil - Ring sticking acc. to CEC M-02-A-93, ASF max = 1 Very short test very severe conditions - 54 hrs full load - Diesel fuel with ~3000 ppm sulfur Seite 8 Source: Volkswagen AG, I.S.P., 2012

9 High Piston Cleanliness and prevent Ring Sticking Test severity driven by high Temperature & low Fuel Quality Pass Result To obtain passing results oil formulations must be strong in several criteria: - Detergency - Dispersancy - Oxidation Stability - Alcalic Reserve Fail Result Seite 9

10 Prevent Blocking of the Diesel Particulate Trap Ash from combusted engine oil may block the particulate trap. This process is not reversible, while Diesel soot can be removed by a regeneration process. Entrance of used Particulte Trap Therefor, ash containing components of the engine oil should give as little as possible blocking of the particulate trap. Failure Mode that has to be prevented: Oil Ash blocking filter channels Sources: Volkswagen Group, 2011

11 Prevent Blocking of the Diesel Particulate Trap Test Rig Installation according to PV 1492 Seite 11 TT.MM.JJJJ Source: Volkswagen, 2012

12 Prevent Blocking of the Diesel Particulate Trap Engine Oil Test Procedure: VW PV 1485 Effect of ash giving additives measured as backpressure increase. Engine Dynamometer Test: 1,9L 96 kw PD TDI Engine Test procedure: without DPF DPF installed Phase 1/5 hrs: Engine run in ref oil Phase 2/2 hrs: Flush run - candidate Phase 3/0,75 hrs: DPF conditioning - candidate Phase 4/24 hrs: Oil consumption run - candidate Phase 5/0,75 hrs: DPF conditioning - candidate 1 Exhaust Temperature 4. Exhaust Backpressure 2. Exhaust Pressure 5. Exhaust Flow Direction 3. Exhaust Pressure Phase 6/144 hrs: Ash loading full load measurement of backpressure Result: increase of backpressure/oil consumption after 144 hrs ash loading phase Seite 12 Source: VW PV 1485, 2008

13 Prevent Blocking of the Diesel Particulate Trap Results of the Test with a Pass Pass Candidate Oil Procedure PV 1485 Test length: 144 hrs Oil type VW LowSAPS SAE 5W-30 Limit is: max. 6mbar/kg -Very little l increase of backpressure allowed Seite 13

14 Wear Testing on TDI Diesel Engines RNT (Radionuclid Wear Measurement) Test VW PV cyl. 1,9 L 77 kw TDI with unit injectors Wear is continously measured Several different dynamic cycles 250 hrs & 650 hrs depending on specification Doted Parts rated: cams & tappets Plus: main & con rod bearing shells, piston rings Wear limits for all parts defined Seite 14

15 Elastomer Compatibility for Diesel Engine Oils Diesel Engine Cleanliness asks for strong Detergency Elastomer materials must be protected. Measures: 1. Elastomer compatibility Test PV 3344: FPM, AEM, ACM criteria: Tensile strength, elongation rupture, hardness Shore A, weight variation 2. Severe elastomer test oil was defined to develop elastomer materials TL Seite 15

16 Approved Engine Oils for Use in Diesel Engines Criteria For all Diesel engines with For all Diesel engines without Particulate traps particulate traps Viscosity Class SAE 5W-30 SAE 5W-40 Specifcation VW VW HTHS-Viscosity 3,5 3,5 mpa*s Sulfated Ash 0.6 to 0.8 Max. 0.8 M% Total base number 6.0 to to 8.0 mgkoh/g Phosphor Content 600 to 800 ~ 800 ppm Additive Package Concentration 15.0 to > to >15.0 M% Types of base Oils Gp III, Gp IV, Gp V Gp III Seite 16 TT.MM.JJJJ

17 Development of Volkswagen Engine Oil Standards Main Steps to Develop Oil Test Methods Engine Test Experiences Meeting of Precision Criteria Inhouse Oil Test Development Volkswagen Engine Oil Standard Test Installation in Independant Labs CEC Oil Test Development Referencing of external Labs Seite 17

18 Service Engine Oil Quality Levels for VOLKSWAGEN Group Cars VW VW VW VW VW VW medium quality level standard drain w/o unit inj. w unit injector 0W-x, 5W-x, 10W-x (x=30, 40) high quality level long drain low Ash for DPF w unit injector FE-properties For FSI SAE 5W-30 only

19 The Volkswagen Engine Oil Approval System - Open for every engine oil manufacturer Volkswagen Engine Oil Standards and all test procedures are public - Original-, Reblend- and Rebrand-Approvals possible - Validity of engine oil approvals is limited to max. 3 years, Rebrand s validities depend on validity at the time of approval. - Validity of test data is limited to 5 years. - Tests accepted from independent labs only - Official approval letter will be issued after succesful approval process - Current status: several hundred engine oils of many different oil companies around the world are approved. Seite 19 Volkswagen Engine Oil Approval Letter

20 Engine Oil Requirements for Volkswagen s Light Duty Diesel Engines - Summary - Latest Diesel Engines are highly efficient and fulfill all emission regulations - This engine technology requests high performance engine oils. - Volkswagen has developed own Diesel engine oil standards. Tests for engine cleanliness, protection of the particulate trap, wear protection, elastomer compatibility were defined. Volkswagen plays an active role in the design of the ACEA Oil Sequences and CEC test developments - Volkswagen is running an own engine oil approval system approved engine oils are available world wide Seite 20