Gasoline/ILSAC GF-3 Procedures
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The Sequence VIB test measures the effects of automotive engine oils on the fuel economy
of passenger cars and light-duty trucks equipped with a low-friction
engine. |
The Sequence VIB (ASTM D 6837)
procedure measures the
effects of automotive engine oils on the fuel economy of
passenger cars and light-duty (3,856 kg, 8,500 lb or less
gross vehicle weight) trucks equipped with a low-friction
engine.
Specifications include:
-
ILSAC GF-3
-
ILSAC GF-4
-
API Category SL
-
API Category SM
Sequence VIB Test Equipment and Procedure
The Sequence VIB test uses a 1993
4.6-liter Ford modular V-8 gasoline engine equipped with an
external oil heating/cooling system and a flying flush
system for changing oil without an engine shutdown.
Fuel consumption is measured at each of 5 speed, load, and
temperature test conditions for an SAE 5W-30 baseline oil
(BC). The candidate oil is introduced and aged for 16 hours
at Aging Phase I conditions, and fuel consumption is
measured for each of the five test conditions.
For Aging Phase II conditions, the candidate oil remains in
the engine and is aged for 80 hours. Fuel consumption is
measured for each of the five test conditions, followed by a
repeat of the BC oil at the five test conditions.
|
Conditions |
Aging
Stages |
Test Stages |
Phase
I |
Phase
II |
1 |
2 |
3 |
4 |
5 |
Speed,
rpm |
1,500 |
2,250 |
1,500 |
800 |
800 |
1,500 |
1,500 |
Normal
power, kW |
15.39 |
23.10 |
15.39 |
2.18 |
2.18 |
15.39 |
15.39 |
Oil
temp, °C |
125 |
135 |
125 |
105 |
70 |
70 |
45 |
Coolant
temp, °C |
105 |
105 |
105 |
95 |
60 |
60 |
45 |
Sequence VIB Test Results
At the end of the test, results are
expressed as a percentage of change in kg of fuel consumed
for the candidate oil after Aging Phase I and Aging Phase II
compared to the BC before and after candidate oil. New oil
and oil after Aging Phase II viscosity at 40 °C and 100 °C
are required.
Fuel economy improvement, which equates to the fuel economy
results obtained from vehicles representative of current
production vehicles running under the current U.S.
Environmental Protection Agency (EPA) testing cycles, is
calculated by the following formula where units for BSFC are
kg/kWh:
|
Stage |
Actual
(kg/kWh) |
|
Normal
Power
(kW) |
|
Time
Factor (H) |
|
Fuel
Consumed
(kg) |
|
1 |
BSFC |
x |
15.39 |
x |
0.0802 |
= |
|
|
2 |
BSFC |
x |
2.18 |
x |
0.0787 |
= |
|
|
3 |
BSFC |
x |
5.81 |
x |
0.0848 |
= |
|
|
4 |
BSFC |
x |
15.39 |
x |
0.0864 |
= |
|
|
5 |
BSFC |
x |
15.39 |
x |
0.0699 |
= |
|
|
Total mass fuel
consumption for all five stages =
|
The following results are computed:
-
Total fuel consumed, as shown above
for the BC oil
-
Candidate oil test stages after
aging Phase I
-
Candidate oil test stages after
aging Phase II
-
BC oil after candidate
The test oil fuel economy improvement
(%FEI) is computed as follows:
|
%FEI Test Oil Phase I = |
{[(BC before × 80%)
+ (BC after × 20%)
– Test oil phase I]/[(BC before × 80%)
+ (BC after × 20%)]} × 100 |
|
%FEI Test Oil Phase II = |
{[(BC before × 10%)
+ (BC after × 90%)
– Test oil phase II]/[(BC before × 10%)
+ (BC after × 90%)]} × 100
|
Sequence VIB Pass / Fail Criteria
Pass/fail criteria for ILSAC GF-3 and
API SL (minimum %FEI versus ASTM BC):
-
SAE 0W-20 and 5W-20 viscosity
grades:
-
SAE 0W-30 and 5W-30 viscosity
grades:
-
All other SAE multiviscosity grades:
Pass/fail criteria for ILSAC GF-4 and
API SM (minimum %FEI versus ASTM BC)
-
SAE 0W-20 and 5W-20 viscosity
grades:
-
SAE 0W-30 and 5W-30 viscosity
grades:
-
All other SAE viscosity grades:
For more information about the
Sequence VIB (ASTM D 6837) procedure, or how you can contract with
Southwest Research Institute (SwRI),
please contact
Guy Stubbs at
gstubbs@swri.org or (210) 522-5039.
sequencevib.swri.org
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Southwest Research Institute® (SwRI®), headquartered
in San Antonio, Texas, is a multidisciplinary, independent, nonprofit, applied
engineering and physical sciences research and development organization with
11
technical divisions.
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