1) The document describes a new test method called OILPAS that measures engine oil aeration through optical imaging of bubbles in a test cell. 2) The OILPAS method dynamically aerates oil samples through agitation and measures the amount of dispersed gas as well as the time required for gas release. 3) Test results on various engine oils showed correlations between OILPAS measurements of aeration and deaeration to results from engine tests, demonstrating its effectiveness as an evaluation method.

1. Engine Oil Aeration
Lab Simulation and Correlation to Engine Testing
Ricardo Hein
Conexo Inc.
Atlanta, GA
+1 678-792-4692
rhein@oilpas.com

2. Aeration properties of lubricating oils
Terms: Air entrainment, Microfoaming, dispersed gas
DEFINITION: Aeration is a characteristic of an oil for
its tendency to retain free air above the absorption
limit at a given pressure and temperature.
• Oil aeration is important for good mechanical operation.
Free air impairs mechanical performance because of:Free air impairs mechanical performance because of:
1. Cavitation in components by absorption and release
2. Wear by irregular (potholed) oil film
3. Oil compressibility (“sponginess”) affects response in
hydraulically driven component operation
4. Oxidation reactions in a larger area of contact with
oxygen and pressure cycles affects drain cycle and
deposit/varnish formation

3. Aeration, Air Release, Foaming
• Previous test methods for aeration testing:
– ASTM D-8047 Engine oil aeration resistance in CAT
C13 heavy-duty diesel engine. COAT replaces D6894
as part of the PC-11
– Air release test ASTM D-3427 and foaming test ASTM
D-892 are insufficient to characterize air/oil interaction
in performance drivetrain components
– ISO 12152 Flender foaming test, stops test to
measure increased volume in a ruler

4. Diagram of Testing Device
Motor
Variable Speed
Controller
Input Tubing
LEDFlashlight
FlowCell
MagnifyingLens
CCDSensor
Circulating pump
USB
Computer Software for
Online Air Measurement
by bubble recognition,
counting, and measuring
Air Impeller
Heating Jacket
Beaker with
Sample of Liquid
Temperature
Measurement
Temperature
Controller
Output Tubing
Online Imaging of Liquids for Particles
and Aeration Scan (OILPAS) instrumentTubing sampling
from beaker
Return tubing
to beaker
Circulating pump

5. New test method to measure Oil Aeration
• Measures dynamic gas holdup in lubricating oils
• Principle of operation/test description
– Aeration by simulation of a air vortex into the oil
• Aeration measured in steady agitation
– 700 ml test fluid; Sample heating (25°C - 120°C temperature control), time– 700 ml test fluid; Sample heating (25°C - 120°C temperature control), time
30 minutes
– Turbine mixer develops vortex action to entrain air, Peristaltic pump moves
a slipstream to test cell
– OILPAS Optical imaging device measures bubbles in the test cell
– The OILPAS algorithm evaluates online the dispersed gas ratio % in oil
– Deaeration measured in time to release and speed of release
• Repeatability demonstrated

6. Set-up – Bench Test 2
Calculation the aeration %
based on bubble
measurement
Pump/Test Cell/
Microscope/Ima
ging
Aerator, conditions
control Speed,
Temperature, Gas
can be simulated in
a dynamic cycle

7. Fluid Aeration Live Testing
Aerated Sample
Samples can be easily changed,
Adjustable frame for
different sample sizes up
to 5 liter
Samples can be easily changed,
allowing for scanning a large
number of samples and
formulations
Speed and Temperature can be
adjusted to simulate a dynamic
driving cycle

8. Measurement System
8

9. Measurement with OILPAS
9

10. Image Device
LED
Flow Cell
CCD Chip
Volume per Image:
1 mm³
Image
Frequency
1 Hz
10
Image Window
2000 μm x 1500 μm
50-500 μm Thickness
5,6 mm
Image Resolution
4416 x 3312 Pixel ca. 14,6 Mega Pixel
Used with 3456 x 2592 Pixel

11. Aeration measurement
Gas content measurement
resolution of
Folie 11
resolution of
Original Images:
3456 x 2592 px

12. CCD Sensor
Pixel layout and count on the CCD-Sensor
CCD Field x : approx. 1.200 μm
CCDFieldy:approx.1μm
Pixel approx. 300 x 300 nm
12
CCDFieldy:approx.
Total Pixel Count: 4.416 x 3.312 = 14,6 Mega Pixel
Particle: Size approx. 1 μm
Consits of approx. 3 x 3 = 9 Pixel

13. Software – Evaluation
Algorithm
Live
Camera
Feed
Algorithm
evaluates
images
Bubble
Histogram
from
Image
Data

14. Time-Resolved measured data
schematic representation based on the volume of bubbles
time
Picture n Pic. n+1 Pic. n+2 Pic. n+3 Pic. n+4
bubbles:
evaluation n
bubbles:
evaluation n+1
bubbles:
evaluation n+2
bubbles:
evaluation n+3
bubbles:
evaluation n+4
OILPAS Measurement System 14
bubbles:
number = 10
surf. = 33203µm²
Volume = 1546 pl
bubbles:
number = 3
surf. = 15924 µm²
Volume = 891 pl
bubbles:
number = 6
surf. = 19615 µm²
Volume = 858 pl
bubbles:
number = 5
surf. = 22718 µm²
Volume = 1196 pl
bubbles:
number = 4
surf. = 12370 µm²
Volume = 524 pl
n-1 n n+1 n+2 n+3 n+4
0
500
1000
1500
2000
Blasenvolumen[pl]
From the bubble volume by a constant factor, a concentration can be calculated
and correlated to headspace methods FEV.

15. Software – Data Diagrams
Gas in oil % is
displayed onlineLife displayed online
Instrument Settings
Life
Feed
Avg. number
of bubbles

16. 4
5
6
Aeration Over Lifetime
Aeration %
Fresh Engine Oil 0.55
Same oil Used 2.45
End of Life, same oil 3.4
Aeration Study of New and Used Oils
-1
0
1
2
3
0 500 1000 1500 2000 2500 3000
GasRatio(%)
Time (Seconds)
New Used End of Life6/20/16
End of Life, same oil 3.4

17. Aeration Comparison 10 Engine Oils
All Samples are engine oil API SN grade 5W-30
20
Aeration Comparison 10 Engine Oils% Air in
RESULTS
Oil Code AD-FS BD-FS GN-FS HN-SB JN-MIN CD-FS DD-SYN ED-FS KN-MIN FD-FS
Description Dexos 2
Full
Synthetic
Dexos 2
Full
Synthetic
Dexos 2
Full
Synthetic
Non Dexos,
Synthetic
Blend
Non Dexos,
Mineral
Dexos 2
Full
Synthetic
Dexos 2,
Synthetic
Dexos 2
Full
Synthetic
Non Dexos,
Mineral
Dexos 2
Full
Synthetic
Aeration (%)
AVG Tested 5.50 3.86 4.30 5.61 9.87 5.54 4.25 3.30 11.08 4.23
Deaeration
Speed (Min) 2.5 3.3 4.1 2.2 3.3 4.3 2.3 3.6 5.0 3.7
8/11/2018
0
4
8
12
16
20
0 300 600 900 1200 1500 1800 2100
AD-FS BD-FS GN-FS HN-SB JN-MIN
CD-FS DD-SYN ED-FS KN-MIN FD-FS
Time in Seconds

18. Correlation to Engine Testing
Oil Sample A: 0W-20 Engine Test WOT Aeration Bench Comments
Mean Aeration During Test (%) 10% 9.1% ~ 10% correlation margin
Time for Deaeration (minutes) Not reported 3:05 Time to release 99.8% of air
Oil Sample B: 5W-40 Engine Test WOT Aeration Bench CommentsOil Sample B: 5W-40 Engine Test WOT Aeration Bench Comments
Mean Aeration During Test (%) 19% 20% ~ 5% correlation margin !!!
Time for Deaeration (minutes) Not reported 2:45 Time to release 99.8% of air
A direct correlation could be found between the bench test rig
and the engine test at WOT regime

19. Conclusions
• Aeration screening in the lab can quickly benchmark the natural
characteristic of an oil to retain free air
• Method was verified at testing a large number of different
lubricating oils, additives and other fluids
• Measures both dynamic gas entrained and air release time
• Air release shows correlation with ASTM D3427 test method• Air release shows correlation with ASTM D3427 test method
• Provides a measure of dynamic gas holdup and bubble size
distribution (not provided by Coriolis sensor), thus adding further
insight into the aeration characteristics of an oil.
• Provides OEMs/Equipment Builders and End Users an alternative
method to test candidate fluids for aeration properties
• Test Method Guides OEM to design components considering the
aeration characteristic of for the oil that is recommended for the
specific application

20. Thank you for your attention.
Any Questions?
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Acworth, GA 30101
USA
678 792 4692