Engine Oil Analysis John C. Hildreth John.Hildreth@uncc.edu July 25, 217
1. Purpose and Objective Purpose Understand how (fast) engine oil changes over time to investigate the potential for extending drain intervals. Objective Push the drain interval limit while maintaining sufficient oil quality to NOT endanger the engine.
2. What happens as oil ages? 1. Physical Change Viscosity increase/decrease and density changes 2. Chemical Change Oxidation reaction of base oil with oxygen Additive Depletion decomposition or mass transfer 3. Contamination Water, glycol, fuel Dirt, soot Wear metals Changes are not independent One source if left long enough may have a domino effect
3. Analysis Equipment Benchtop analysis to avoid time delay in results OSA4 TruckCheck ($5k) and Spectro Scientific MicroLab 3 ($k) Chemical analysis by infrared spectrometer TBN, oxidation, nitration, water, soot, glycol Viscosity (4 and C) by Kinematic Viscometer Metals analysis by Optical Emission Spectrometer Perform ~3 analyses per hour Consumables CheckFlush fluid Standardization fluids
3. Threshold Oil Parameters Full list of thresholds in project report Key Parameters 1. TBN: 4 mg KOH/g 2. Viscosity: 12.5 1.3 cst (4 wt oil) 3. Silicon: 4 ppm ( ppm if dirt) 4. Aluminum: 15 ppm (with Si) 5. Iron: ppm. Potassium and Sodium (glycol): 5 ppm both
4. Baseline Oil Analyses Viscosity, 4C (cst) Viscosity, C (cst) Conoco HD Fleet Supreme Conventional 15W-4 Published Avg. Measured Xtreme Fleet Synthetic Blend 15W-4 Published Avg. Measured Published Div Bulk Tank Shell Rotella T Full Synthetic 5W-4 Avg. Measured Div 3 Bulk Tank Retail A Retail B 115 N/A 11.4.2 7 N/A 1 N/A N/A 15.2 14.99 15. 13.9 14.2 12.4 13.2 12.9 13.1 Viscosity Index 135 N/A 144 141 19* N/A 15 N/A N/A TBN (mg KOH/g) * Value not published, calculated value 9.5 9.33.1.1. 9.53 9.53 9.45 9.3
5. Analysis Program 214-1 Charlotte Area All machines in 4 classes 47 total machines Selected machines on extended drain intervals Ultimately put all IMAP trucks on extended intervals Conventional & synthetic oils 21-1 Wilmington Area Select machines in 4 equipment classes on extended drain intervals 13 total machines Included Navistar DT4 engine to continue study 3 additional engines to extend previous study Blend & synthetic oils
. Analysis Results Collected 3 samples (15 ml) at pre-determined intervals and averaged the results Oil Equipment No. of Samples Analyzed No. of Machines Sampled Conv 29 Crew Cab Chassis (DT4) 17 13 Syn 2 IMAP Truck 35 12 Conv 33 Mowing Tractor 12 Conv 311 Sideboom Mowing Tractor 252 14 Blend/Syn 25 Single-Axle Dump (DT4) 3 1 Blend 212 Tandem-Axle Dump 3 Blend 314 Backhoe Loader 24 3 Blend 154 Excavator 27 3 Total 1,7 57
. TBN Conventional Oil Total Base Number (mg KOH/g) 12 4 2 33 & 311 Mowing Tractors Tractors performed similarly TBN decrease.4 per hrs Threshold at 135 hrs y = -.39x + 9.37 R² =.423 2 3 4 5 Oil Age (hrs) 311 33 Total Base Number (mg KOH/g) 12 4 2 29 Crew Cab Chassis TBN is not use dependent y = -.2x + 9.22 R² =.171 2, 4,,,, 12, Oil Age (miles) TBN remained unchanged to 11k miles 29 215-377
. Viscosity Conventional Oil 1 33 & 311 Mowing Tractors 1 29 Crew Cab Chassis 1 1 Vicosity at C (cst) 14 12 311 33 Vicosity at C (cst) 14 12 29 215-377 2 3 4 5 Oil Age (hrs) 311 might trend upward All results within specification 2, 4,,,, 12, Oil Age (miles) Some low viscosity Not time (use) dependent
. TBN Synthetic Total Base Number (mg KOH/g) 12 4 2 2 IMAP Trucks -.4 L More variable Faster (?) to threshold y = -.4x + 9.1 R² =.57 2, 4,,,, 12, 14, Oil Age (miles) Total Base Number (mg KOH/g) 12 4 2 2 IMAP Trucks -.7 L Fairly consistent / predictable 12k miles to TBN of 4 y = -.4x + 9. R² =.24 2, 4,,,, 12, 14, Oil Age (miles)
. Viscosity Synthetic 1 2 IMAP Trucks -.4 L 1 2 IMAP Trucks -.7 L Viscosity at C (cst) 1 14 12 Viscosity at C (cst) 1 14 12 2, 4,,,, 12, 14, Oil Age (miles) Low viscosity at 1k miles Fuel dilution (known to the.4l engine) 2, 4,,,, 12, 14, Oil Age (miles) At the SAE min for 4 wt oil Very consistent
. TBN Conv. vs Synthetic One oil drain in two IMAP trucks with.7l engine Total Base Number (mg KOH/g) 12 4 2 Conventional Synthetic 2, 4,,,, 12, 14, Oil Age (miles)
. TBN Synthetic Blend TBN (mg KOH/g) 212 Tandem Axle Dump Trucks - Preliminary Results TBN (mg KOH/g) 9 7 5 4 3 2 1 9 7 5 4 3 2 1 y = -.4x + 9.72 R² =.7121 2, 4,,,, 12, 14, Oil Age (miles) y = -.24x +.71 R² =.93 5 1, 1,5 2, 2,5 3, Oil Age (gals) TBN (mg KOH/g) 9 7 5 4 3 2 1 y = -.71x + 9.45 R² =.93 2 4 1, Oil Age (hrs)
. Oil Contamination Contaminant Content (%) 1..9..7..5.4.3.2.1. 311 Sideboom Mowing Tractors Soot (3% max) Water (.5% max) Glycol (% max) 2 3 4 5 Oil Age (hrs)
. Wear Metals 33 Tractors 2 7 Aluminum (ppm) 15 5 Copper (ppm) 5 4 3 2 5 15 2 25 3 Oil Age (hrs) 5 15 2 25 3 Oil Age (hrs) 12 12 Iron (ppm) 4 2 Chromium (ppm) 4 2 5 15 2 25 3 Oil Age (hrs) 5 15 2 25 3 Oil Age (hrs)
. Analysis Results TBN key to chemical change Time (use) dependent Viscosity decrease due to fuel dilution Specific to engine type Contamination was not an issue (water, glycol, soot) Very little wear metals produced Copper passivation Isolated engine issues
7. Recommendations Class Opportunity to extend drain intervals without significant danger of unacceptable oil quality Engine Recommended Drain Interval Comments 29 Navistar DT4, miles Likely longer, need additional data 2 33 311.4L 5, miles Viscosity / Fuel Dilution.7L, miles Consider conventional oil All 5 hrs Likely longer, need additional data
7. Estimated Annual Savings Class Engine (Sump) Count Avg Ann. Use Est. Cost per Oil Change Estimated Annual Savings Oil Changes per Machine Annual Cost Annual Oil (gals) 29 Navistar DT4 (3) 14,17 mi $ 25 1 per yr $ 41, 1,23 2 33 PwrStrk.4L (15) 22 2,4 mi $ 17 None $ PwrStrk.7L (13) 55 33,14 mi $ 17 3 per yr $ 2,5 53 NH.7L (22) 4 21 hrs $ 3 None $ Deere 4.5L (1) 54 32 hrs $ 3 1 per yr $ 1,2 21 Deere.L (24) 43 42 hrs $ 3 1 per yr $ 12,9 25 311 Deere 4.5L (1) 2 54 hrs $ 3 1 per yr $, NH.7L (22) 55 37 hrs $ 3 1 per yr $ 1,5 32 Estimated Annual Savings $ 12,5 2,22
Engine Oil Analysis John C. Hildreth John.Hildreth@uncc.edu July 25, 217