Evaluation and Qualification of Gasoline and Diesel Engine
Meeting the Future
For more than 65 years, lubricant, additive, and equipment
manufacturers have been striving to improve automotive engine oil performance. Southwest
Research Institute (SwRI) serves as a technical partner to help clients develop engine
oils that meet modern engine requirements and future lubricant performance challenges.
Lubricants for spark-ignited engines are updated as the
performance needs of new engines change and as new regulations, such as the 100,000-mile
emissions durability requirement for passenger cars, are imposed. Lubricants must not only
protect the engine, they must also be compatible with the exhaust oxygen sensor and
catalyst. To help vehicle manufacturers meet corporate-average fuel economy standards,
industry is developing advanced engine oils that improve fuel efficiency by reducing
Diesel engine designs are evolving to meet future emissions and
fuel economy requirements. New engines exhibit lower exhaust emissions and greater
efficiencies as a result of improved combustion systems, design, and materials, although
they challenge fuels, lubricants, and traditional engine oil test procedures.
Diesel Engine Lubricants
To ensure long engine service, lubricants are compared to a
series of specifications, such as MIL-L-2104H and API service classifications CI-4 and CJ-4.
SwRI analyzes lubricants through engine test procedures to determine factory fill, factory
branding as genuine oils, and service fill. The Institute performs all recognized test
- Mack T-8
- Mack T-11
- Mack T-12
- Cummins ISM & ISB
- GM RFWT
- Caterpillar IM-PC
- Caterpillar 1K
- Caterpillar 1N
- Caterpillar 1P
- Caterpillar 1R
- Caterpillar C13
SwRI has 38 test stands available for the diesel
lubricant test procedures, which utilize engines representative of heavy-duty diesel
engines operating in modern commercial fleets and off-highway applications.
SwRI simulates heavy-duty diesel engine commercial
fleet operations in single-cylinder test stands.
As diesel engines are modified to achieve low exhaust
emissions, new and improved fuels and lubricants evaluation methods are necessary. Changes
such as higher fuel injection pressures, electronic engine controls, and higher top ring
placement on the piston will help achieve lower emissions. Requirements for low oil
consumption and for lubricants that are compatible with oxidation catalysts and capable of
maintaining long engine life will result in new or revised additive-treated lubricants.
Changes in diesel fuel mandated by the U.S. Environmental
Protection Agency and the California Air Resources Board may require changes in lubricants
and additives to improve combustion and to control injector deposits.
abound for advanced product technology. SwRI offers extensive capabilities in diesel
engine lubricants research, including:
- Crankcase oil soot loading
- Diesel fuel additives
- Combustion improvers
- Injector deposit control
- Component wear and life
- New procedures and development of lubricants for alcohol- and
natural gas-fueled heavy-duty engines
- Lubricant-emissions relationship studies
- New and revised multi-cylinder and single-cylinder procedures
- Detroit Diesel
- John Deere
- General Motors
- Lubricants for advanced technology engines
- Low-friction engine lubricants
In addition to standardized testing, the Institute offers
screening tests and other specialized or focused laboratory test procedures.
Gasoline Engine Lubricants
The 288-hour VE engine oil performance test simulates
stop-and-go urban and moderate freeway driving.
The Institute offers complete testing services for a
variety of four-stroke cycle lubricant specifications, including SAE, ASTM,
ILSAC GF-3, GF-4 and GF-5 as well as API
service classification SL, SM and SN engine oils.
Standardized testing includes:
The Ball Rust Test
evaluates the anti-rust ability of fluid lubricants. The procedure is
particularly suitable for the evaluation of automotive engine oils under
low-temperature, acidic service conditions.
The Sequence IIIF procedure measures oil
thickening and piston deposits under high-temperature conditions and
provides information about valve train wear. The test simulates high-speed
service under relatively high ambient conditions. A 1996/1997 231 CID
(3,800 cc) Series II General Motors V-6 fuel-injected gasoline engine is
used. Using unleaded gasoline, the engine runs a 10-minute initial
oil-leveling procedure followed by a 15-minute slow ramp up to speed and
load conditions. It then operates at 100 bhp, 3,600 rpm, and 155 degrees C
oil temperature for 80 hours, interrupted at 10-hour intervals for oil level
The Sequence IIIG test
evaluates engine oils for its ability to protect against oil thickening and
engine wear during moderately high-speed, high-temperature service. A
1996/1997 231 C.I.D. (3800 CC) Series II General Motors V-6 fuel-injected
gasoline engine is used for this procedure.
Sequence IVA test evaluates an automotive lubricant’s ability to protect
against cam lobe wear for overhead valve train equipped engines with sliding
cam followers. The test is conducted on a Nissan KA24E engine with 24L
displacement, water-cooled, fuel-injected, four-cylinder in-line overhead
camshaft. Camshaft lobe wear is measured at seven locations around 12
lobes. Secondary results include cam lobe nose wear and measurement of iron
wear metal concentration in the used engine oil.
The Sequence VG test evaluates an engine oil’s control of deposits under
operating conditions selected to accelerate deposit formation. The test
engine is a Ford 4.6L, spark ignition, four-stroke, eight-cylinder V
configuration. Features of this engine include an overhead camshaft, a
cross-flow fast-burn cylinder head design, two valves per cylinder and
electronic port fuel injection. It is based on the Ford 4.6L EFI Crown
Victoria passenger can engine.
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. 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.
Sequence VID test measures the effects of automotive engine oils on the fuel
economy of passenger cars and light-duty trucks. A 2008 3.6L V6 General
Motors gasoline engine equipped with an external oil heating/cooling system
and a “flying flush” system for changing oils without an engine shutdown is
used for this test. Test results are expressed as a percent change in kg of
fuel consumed for the candidate oil after aging phase I and after aging
phase II relative to the baseline oil before and after candidate oil.
Sequence VIII test evaluates automotive engine oils for protection of
engines against bearing weight loss. This method covers SAE grades 5W, 10W,
20, 30, 40 and 50, as well as multi-viscosity grades, used in spark-ignition
engines. An oil is evaluated for its ability to protect the engine and oil
from deterioration under high-temp and severe service conditions.
Correlation of test results with those obtained in automotive service has
not been established. This procedure uses a carbureted, spark-ignition
Cooperative Lubricant Research Oil test engine run on unleaded fuel. The
test length is 40 hours and test speed is 3150 r/min. Test oil temperature
is 143 degrees C or 290 degrees F. At the end of the test, the connecting
rod bearing weight loss is measured.
SwRI evaluates bearing weight loss using L-38 standard
lubricant test stands.
Gasoline Two-Stroke Cycle Lubricants
Concern over energy conservation and environmental pollution
has led to leaner oil-to-fuel ratios, which, in turn, have affected lubricant
requirements. Exhaust emission reduction could contribute to the two-stroke cycle engine's
viability in the near future. The two-stroke cycle engine provides better power-to-weight
ratio, higher specific power output, and less frictional loss than the four-stroke engine.
Many major automobile manufacturers have already built experimental fuel-injected,
two-stroke cycle engines for automotive applications.
The Institute evaluates lubricants used in two-stroke cycle,
air-cooled engines using the ASTM-TC test sequence, which evaluates the lubricant's
- Resist combustion chamber deposit-induced preignition
- Prevent ring sticking
- Inhibit deposit formation
- Reduce scuffing
- Resist spark plug fouling
SwRI also offers all engine and chemical tests required to
evaluate lubricants for two-stroke, water-cooled engines, including the National Marine
Manufacturers Association TC-W3TM specification tests. These requirements have led to
improved lubricants that exhibit higher levels of resistance to ring sticking and loss of
cylinder compression. In the future, biodegradability of lubricants may become a
significant factor for lubricants formulated for the boating industry.
For two-stroke, air-cooled engines, the International Standards
Organization (ISO) has recently adopted worldwide test procedures to evaluate lubricants
for exhaust smoke, exhaust system deposits, lubricity, and piston cleanliness. These test
methods, conducted by SwRI, have supplemented the ASTM-TC specification tests previously
used by industry.
With trained personnel and modern laboratory facilities, SwRI
helps the petroleum industry monitor future trends and develop lubricants that meet
current requirements. In addition, SwRI engineering and technical staff members are
available to develop and operate special two-stroke cycle laboratory tests or to design
and coordinate custom field tests to meet unique requirements.
Advanced spark-ignited, two- and four-stroke cycle engines
operating on gasoline, alcohol, natural gas, or mixed fuels sometimes require improved or
specialized lubricants. Test services are usually customized and frequently incorporate
modification of existing test methods.
Following testing, specially trained gasoline and
diesel engine lubricants personnel visually rate parts for sludge, rust, varnish, carbon,
and wear. SwRI staff members lead industry workshops and help develop new rating aids and
Institute staff members have expertise in many areas,
- European CEC test methods
- Modified Sequence VI: evaluation of fuel/additive effects on
- Fuel-efficient engine oil performance in reduced-friction
- Alcohol fuels/alternative fuels
- Engine durability
- Ring and bore wear
- Lubricant evaluation
- Fuel additives
- Engine/component durability testing
- SAE J1312 engine power mapping
- SAE J1349 engine power test
- Modified sequence tests
- Piston aircraft lubricant tests
- Exhaust valve seat recession
- Induction system deposits
- Port fuel injector deposits/injector flow loss
- Oil-foaming tendency and aeration
- Low-temperature evaluation
- Turbocharger durability and lubrication
- Real-time kinematic viscosity
The Institute's experienced staff members provide
special assistance in experimental projects to develop customized test procedures and
precise test equipment for measurement and control.
In addition to having received several departmental audit
approvals, all departments in the Fuels and Lubricants Research Division have
achieved certification to ISO 9002, the "Model for Quality Assurance in Production
and Installation" and accreditation to ISO/IEC Guide 25 (EN 45001), "General
Requirements for the Competence of Calibration and Testing Laboratories."
For more information about diesel or gasoline engine lubricants,
contact Michael Lochte,
director, Engine Lubricants Research Department, Phone (210) 522-5430, Fax
(210) 522-6858, Office of Automotive Engineering, Southwest Research Institute, P.O. Drawer 28510, San Antonio, Texas
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