Falex Tribology Case Study 4 Friction Modifiers

Falex Tribology Case Study 4
Quality
Knowledge
Partner Solutions
Friction Modifiers
MUST Precision Testing
•
Detecting efficiency of friction
modifiers with < 5%
•
CoF with 0.01 level precision
• Quantify efficiency of additives
Organic friction modifiers are becoming more important for reducing friction in boundary
lubrication regime. Even 3—5 % reduction in friction can have a significant impact on the
overall efficiency of the engine and on the environment. As new formulations are made, the
quantification of the improvement requires extremely precise friction measurements that
are not possible with conventional high load tribometers. Falex MUST microtribometer with
a force resolution of 0.2 µN is used to measure the friction reduction offered by organic
friction modifiers when added to Base oil and Diesel fuel.
Effect of modifiers on lubricity of Diesel
0.5
Diesel
GMO
Modifier A
Modifier B
0.4
Average CoF
New formulations have the potential
to reduce friction more than the
reference Glycerol mono-oleate
(GMO).
0.3
0.2
0.1
v/L=0.0033
v/L=0.01
v/L=0.05
v/L=0.0167
0.0
Rotating or reciprocating tests
possible.
Effect of modifiers on lubricity of Base oil
0.15
Baseoil
GMO
Modofier A
Modifier B
v/L=0.05
v/L=0.0167
0.14
0.13
0.12
Average CoF
Falex MUST microtribometer offers
precise friction measurements ideal
for friction modifier, organic films
etc.
0.11
0.10
0.09
0.08
0.07
0.06
v/L=0.01
v/L=0.0033
0.05
Falex Tribology nv
Wingepark 23b | 3110 Rotselaar – Belgium
T +32 (0)16 40 79 65 | F +32 (0)16 40 51 28 | [email protected] | www.falex.eu
Falex Tribology Case Study 4
Quality
Knowledge
Partner Solutions
Most conventional tribometers are
constructed to perform wear and extreme
pressure tests, with friction measurement
as an add-on.
HFRR Test Rig
1 N load
But the friction measurement is not
precise enough (see figures).
HFRR Test Rig
1 N load
2 N load
400
W e a r s c a r (µ m )
Conventional tribotesters lack the
precision and sensitivity to detect small
frictional differences with confidence.
300
200
100
0
GMO
2 N load
Modifier A
C o e ffic ie n t o f fric tio n
1.5
1.2
0.9
0.6
0.3
0
GMO
Modifier A
Even specialised equipment such as the
HFRR (High Frequency Reciprocating Rig)
for lubricity of diesel fuels and the Falex
Four Ball Wear test for lubricants, relatively
high contact pressures are used to obtain
measurable wear.
Falex Four Ball Wear Tester
Average Coefficient of friction
0.16
0.14
The mechanical construction needed
for a friction tester must allow at
least 0.1% resolution if we want to
distinguish 1% differences in friction
coefficient for a typical boundary
lubrication coefficient of 0.1.
The Falex MUST microtribometer
uses a displacement measurement of
a bending element. This
measurement’s resolution is 0.02 µm.
When tests are done in the range of
50 mN normal load, the force
resolution is 0.02 mN. This is
sufficient to distinguish 1% variation
in friction coefficient.
0.12
The MUST Tester
0.10
0.08
0.06
0.04
No
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Falex Tribology nv
Wingepark 23b | 3110 Rotselaar – Belgium
T +32 (0)16 40 79 65 | F +32 (0)16 40 51 28 | [email protected] | www.falex.eu