|The Army’s Impact
on the Fuel and Lubricant Industry
|by Maurice E. Le Pera
The author takes a historical look at the Army’s fuel and lubricant program and its effect on commercial lubricants.
Few people may realize that a significant number of advances in fuels and lubricants in the past 50 years are the direct result of Army research, development, and testing. The fuel and lubricant-related problems that occurred in Army ground vehicles and equipment during World War II and the Korean War surfaced a need for sustained funding of petroleum, oils, and lubricants (POL) research and development. These problems included severe vapor locking in tanks and vehicles operating in hot environments, engine malfunctions because of insoluble gum and deposits that formed when gasoline was stored in drums, and the inability of gear lubricants to provide needed wear and moisture corrosion protection for vehicle differential systems.
The importance of fuels and lubricants for the U.S. military’s many types of wheeled and tracked vehicles and stationary equipment became evident during World War II and the Korean War. Since the Army had the greatest quantity and diversity of vehicles and equipment systems, its problem was the most critical in the Department of Defense.
For example, when the Army’s Ordnance Lubrication Program began in 1941, no standard lubricants existed for military vehicles and equipment. At that time, the Army used 2 types of engine oil, 2 types of gear lubricants, and 3 types of grease, resulting in a total of 22 different grades of lubricant for automotive equipment alone, not including those intended for special purposes. These commercial products were found to be inadequate for meeting the Army’s stringent operational requirements. So, the Ordnance Corps and industry began cooperating to develop bench tests, engine dynamometer tests, and rating procedures needed to uniformly define the performance requirements needed for military fuels and lubricants.
Early in 1942, Harry Mougey of General Motors Research and Lew Blanc of Caterpillar Tractor Company realized that the superior quality of engine oils used by the German Army could lead to the Allied Forces losing the war. Armed with this information, they went to the Department of War and strongly recommended that the Army develop improved engine and gear oils for wheeled and tracked vehicles. This resulted in the initial involvement of the Illinois Institute of Technology Armour Research Foundation to develop the test methods needed to better define the performance of military automotive lubricants. The Army also requested the Coordinating Research Council’s (CRC’s) assistance in the study. [The CRC is a nonprofit organization that manages engineering and environmental studies on the effects of petroleum products on vehicles.]
Establishing the SwRI Research Facility
Because of the many fuel and lubrication problems that surfaced during World War II and the Korean War, the Army realized that it needed a central activity that could address them and conduct research and development on future fuel and lubricant requirements. Norman L. Klein of the Ordnance Corps was responsible for the Army establishing a dedicated, contractor-operated, Government-owned research laboratory at Southwest Research Institute (SwRI) in San Antonio, Texas, in May 1957.
Klein had been directly involved with addressing many of the operational problems that the Army had experienced with its vehicles and equipment and had actively participated in many of the CRC cooperative projects. While participating in these CRC activities, he met the SwRI vice president responsible for initiating much of the work being conducted by CRC and the Society of Automotive Engineers (SAE) in selecting and standardizing engine dynamometer tests for defining lubricant performance. When Ordnance Corps leaders discussed the idea of having a dedicated activity established specifically to address the requirements for military automotive fuels and lubricants, Klein saw the obvious advantages of such a laboratory.
SwRI had the available space, was very connected with the automotive and petroleum additive industries, and had field-testing capabilities, engine dynamometer stands, and laboratories available. After obtaining concurrence from industry, Klein went to the senior Army management and convinced them of the need to establish such a facility.
When the Army officially opened the Army Ordnance Corps Fuels and Lubricants Research Facility at SwRI, it represented a new approach in Government-sponsored research. Although it was Government-owned, the facility was built on institute land and was completely staffed and operated by SwRI under contract with the Ordnance Corps.
The facility at SwRI has undergone several name changes in the past 50 years: Army Fuels and Lubricants Research Laboratory, Belvoir Fuels and Lubricants Research Facility, and now Tank Automotive Research, Development and Engineering Center Fuels and Lubricants Research Facility. For purpose of simplification, it will be referred to as the Army Fuels and Lubricants Research Laboratory (AFLRL) for the remainder of this article.
Since the spark-ignition engine powered most of the Army’s ground vehicles and equipment during World War II, operational problems with using the commercial gasoline available at that time surfaced early. The two types of major problems affecting the ground forces were related to volatility (such as vapor locking and hard starting) and storage instability (such as gum formation causing valves to stick and abnormally heavy deposits in fuel intake systems). These problems seriously reduced readiness and maintainability. To combat these problems, the Ordnance Corps requested assistance from industry through the CRC. The CRC conducted a number of vehicle tests from 1942 through 1946 at Army locations in southern California to study the volatility and storage instability problems that had been encountered in North Africa and Italy. Much, if not all, of the information that was generated by these test programs eventually became incorporated into the industry standard for gasoline.
A report published in 1953 stated that, without more information on the behavior of gasoline and its components in storage, no method could be developed to predict storage stability accurately. In response to this report, in 1955, the U.S. Bureau of Mines and the Stanford Research Institute began long-range programs of basic research into the mechanisms of gum formation in gasoline. Much of this Army-sponsored research was later used by the petroleum industry to improve the stability of the commercial gasoline being marketed. One example of this was the Army’s development of a gum preventive compound (Federal Specification VV–G–800) in 1962, which was intended to be used for stabilizing gasoline in power generation units and for keeping vehicles operational during standby storage. This gum-preventive compound subsequently found a home in the commercial marketplace when several companies began to market it under a variety of different names.
|This engine-liner test rig was used in the research exploring the tribology needed for low heat rejection engine technology.
Automotive Engine and Gear Oils
One of the more significant accomplishments initiated in the early 1940s was the establishment of a process for reviewing, approving, and certifying automotive engine and gear oils. Initially, the qualification of oils under the early Army specifications involved a commercial practice in which suppliers obtained approvals, independently from both Caterpillar Tractor Company and General Motors Corporation, using their separate engine-testing procedures. These test results were then used to develop the qualification list maintained by the Ordnance Corps. Situations arose, however, in which changes to both base stocks and additives were necessary, resulting in formula modifications and subsequent requalfications. Because of this, it became evident that direct supervision by the Ordnance Corps was needed to effect changes as quickly as possible so that adequate supplies of qualified oils were available to meet the wartime requirements.
In 1943, the Ordnance Corps assumed responsibility for the qualification program and established the Ordnance reviewing committee composed of representatives from Caterpillar Tractor Company, General Motors Corporation, the Armour Research Foundation, and the Ordnance Corps. This committee, which initially addressed engine oils, convened its first meeting in May 1943. Later that year, a parallel committee using a different group of industry representatives was established to cover the qualification of gear lubricants. The two Ordnance reviewing committees became known as the Army’s engine and gear oil reviewing committees. In July 1959, the meeting location moved from the Armour Research Foundation to the recently established AutoResearch Laboratories, Inc. The Army’s engine and gear oil reviewing committees continued to function until 1977, when the Army relinquished its direct sponsorship and contracted the SAE to perform this function. These functions then became part of the SAE Lubricants Review Institute and remain so today.
The military approval process satisfied a need for engine and vehicle manufacturers, other Government agencies, commercial fleet operators, and others for a methodology that both described the performance level of lubricating oils for their vehicles and equipment and provided a means for ensuring or certifying the quality for each approved formulation.
By introducing new combinations of requirements, the Army forced major changes in how engine oils were formulated. These changes included incorporating requirements for both gasoline- and diesel-fueled engines into one specification, adding transmission power-shift requirements to engine oil specifications, and allowing for the use of recycled components. Oil companies that marketed worldwide required their products to be approved and qualified under the military engine and gear oil specifications. Unfortunately, few of these approvals were ever used for their intended purpose—responding to Government bid solicitations—which led to the Army’s decision to relinquish its responsibilities to SAE. A significant amount of the procedural methodology used in the past military approval process has since been incorporated into the current American Petroleum Institute (API) Engine Oil Licensing and Certification System. Another contribution somewhat aligned with the military approval process involved using military specifications as a basis for establishing industry’s performance standards for automotive engine and gear lubricants. In many cases, the military specifications helped to set the performance requirements for the different API categories.
During the early 1950s, the Army had observed that its multipurpose gear lubricant was not providing satisfactory lubrication for some of its vehicles, nor was it providing adequate protection against moisture corrosion. These deficiencies prompted the Army to contract the Armour Research Foundation (and later AutoResearch Laboratories) to develop qualification tests for the Army’s multipurpose gear lubricants. This effort, initiated in 1952 and completed in 1960, involved a multiphase project to develop test procedures for the evaluation of hypoid gear lubricants and to study the loading, temperature, and sliding velocity conditions of automotive hypoid gears. [Hypoid gears are gear wheels connecting nonparallel, nonintersecting shafts, usually at right angles.]
The project generated the basic data needed for the CRC’s gear lubricants group, which was developing test procedures that eventually became known as the L–37 (evaluation of load-carrying capacity of lubricants under conditions of high speed and low torque, followed by low speed and high torque), the L–42 (evaluation of load-carrying properties of lubricants under conditions of high speed and shock loading), the L–33 (evaluation of moisture corrosion resistance of automotive gear lubricants), and the L–60 (evaluation of the thermal and oxidative stability of lubricating oils used for manual transmission and final drive areas). These four test methods remain the principal “tools” for defining performance of automotive multipurpose gear lubricants used by the military and industry and are generally accepted worldwide.
|This apparatus was used for conducting the L–33 corrosion test for hypoid gear oils.
Many of the major contributions involving automotive lubricants originated from AFLRL. Those accomplishments include—
- Developing a blow-by diversion piston for cleaner crankcases.
- Developing approaches for extended oil drain intervals.
- Introducing and demonstrating synthetic-based oils for fleet-wide applications.
- Introducing powershift transmission requirements into engine oils.
- Defining lubrication requirements for two-stroke, heavy-duty diesel engines.
- Developing a basic understanding of low temperature sludge deposit formation.
- Establishing acceptability of military engine and gear oils using recycled stocks.
- Defining mechanisms for cylinder bore and piston ring wear in methanol-fueled, spark-ignition engines.
- Demonstrating the usability of military engine oils as power-transmission and hydraulic fluids.
SwRI was granted a patent for the blow-by diversion approach. The research revealed that diverting the combustion blow-by from the crankcase reduced the rate of sludge formation, which resulted in cleaner engines, less wear, and extended oil drain intervals. The methodology involved using one or a combination of the four different means for diverting the blow-by, resulting in subsequent modifications to piston and ring configurations. The work on blow-by diversion added to the knowledge of engine oil degradation, which in turn led to the development of improved detergent and dispersant formulations, giving a great understanding of extended oil drains and, ultimately, better long-life engine oils.
This concept was subsequently implemented in a study conducted several years later in which the Army was pursuing approaches for extending oil drain intervals for tactical equipment. In concert with this, AFLRL had proposed a sealed crankcase concept that embodied reduced blow-by diversion and improved engine oil quality. This concept is used in the Caterpillar I6 7-liter C7 engine for the Stryker vehicle, which is fitted with a special metering device that automatically withdraws used oil to be fed into the combustion chamber while simultaneously adding new oil into the crankcase so the amount of oil in the crankcase remains constant.
Synthetic-based engine oils were introduced in 1967 for all Army vehicles and equipment operating in Alaska using the Aberdeen Proving Ground Purchased Description Number 1 that later was converted into MIL–L–46167, commonly referred to as Arctic Engine Oil (OEA). This engine oil was essentially SAE 0W–20, which was quickly adopted by commercial operators building the Alaska pipeline system during the 1970s. Because of the successful performance of OEA in a variety of engine and powertrain systems, the Army subsequently field-tested this oil at several locations in Army tactical and combat vehicles and equipment to assess its applicability in moderate-to-hot temperatures. These tests were conducted at Fort Carson, Colorado; Fort Lewis, Washington; and Fort Bliss, Texas. In each case, OEA performance was satisfactory and no adverse effects were observed even while operating in the high-temperature environments. Although the Army did not pursue a fleet-wide conversion at that time, the successful performance of OEA both in different engine and powertrain systems and in various operating environments demonstrated its feasibility. This success attracted many commercial fleet operators to consider, and later adopt, synthetic-based engine oils.
In the late 1960s, an industry task force and Army personnel joint meeting was convened to resolve differences between two gasoline standards: industry’s American Society for Testing and Materials (ASTM) gasoline standard, ASTM D439, and the military’s post-camp-station automotive gasoline, Federal Specification VV–G–76. The major differences involved the manner in which gasoline volatility classes were established. This and subsequent meetings revealed the need for a more comprehensive temperature study that would provide the information needed to realistically predict meaningful minimum and maximum temperatures suitable for procurement specifications.
The Army subsequently funded a study in 1972 involving the processing of hourly temperature data from 340 first-order weather stations covering the past 20 to 30 years. These data were then processed by computer, ranked into monthly maximum and minimum percentiles, and presented in tabular form as well as using isothermal maps for defining geographical regions. The Army selected the 10th percentile for predicting the prevailing low temperatures and the 90th percentile for predicting the prevailing high temperatures. This approach was accepted by industry and became the standard methodology for use in specifications covering a wide range of petroleum and related products. For example, the current industry standard for diesel fuel, ASTM D975, references this methodology for selecting cloud point requirements. [The cloud point is the temperature at which the solids in the oil begin to separate, causing a cloudy appearance.]
Starting in the late 1970s, the Army did a considerable amount of fleet testing to demonstrate the acceptability of using alternative fuels, beginning with gasohol (10 percent ethyl alcohol in gasoline) and then M85 methanol and JP–8, an aviation kerosene fuel that became the single fuel for the battlefield. Because of the success of the Army’s field demonstrations, many commercial operators subsequently adopted these practices.
The initial use of aviation kerosene fuels in diesel engines resulted in the Army’s pioneering work to study fuel lubricity requirements, which led to SwRI developing the Scuffing Load Ball-on-Cylinder Lubricity Evaluator in 1991. This procedure was adopted with the introduction of low-sulfur diesel fuels in the United States and became one of the two ASTM methods currently in use for measuring diesel fuel lubricity.
|This heavy-duty Army truck was powered by the experimental adiabatic engine.
The Army continues to contribute a significant amount of research to further the high-temperature tribology for future diesel engines. [Tribology is the study of the effects of friction on moving machine parts and how to eliminate them using lubrication.] Since 1975 when the Army’s Tank-Automotive Command (TACOM) and Cummins Engine Company initiated an adiabatic [without loss or gain of heat] engine program, research has continued to promote the tribology needed for low-heat-rejection engine technology. Significant efforts have resulted in formulating several types of high-temperature synthetic engine oils capable of withstanding top ring reversal temperatures that exceed 310 degrees Celsius. Under these severe high-temperature conditions, a liquid lubricant by itself does not fully provide all the lubrication needed.
Other approaches have involved the application of thermal barrier coatings to piston surfaces and the cylinder bore areas. One of the materials showing promise for this application is low-temperature iron titanate (LTIT), which has provided the best performance. Current efforts have focused on bringing this LTIT technology into the commercial marketplace.
Research at the Army Research Laboratory (co-located with the National Aeronautics and Space Administration’s Glenn Research Center in Cleveland, Ohio) is underway to develop oil-free turbocharger technology that will improve both the performance and reliability of the Army’s diesel-powered vehicles. The turbochargers used on most diesel engines are oil lubricated and prone to maintenance and reliability problems resulting from oil coking, leakage, and consumption. [Oil coking refers to the oil changing into carbon.] This collaborative technology, now under development, involves the use of foil air bearings and tribological coatings that have been developed by industry and Government. As an example of this ongoing work, an oil-free turbocharger is scheduled to be engine-tested for possible future application to the Stryker vehicle.
The Army recently initiated a feasibility study to consider developing a common powertrain lubricant for combat and tactical vehicles and equipment that would reduce life-cycle costs. Since the Army currently has three engine oil specifications (resulting in nine grades), the intent is to reduce these to a single powertrain lubricant that will have only one grade, provide preservative properties, and be capable of operating in arctic to desert environments. This approach involves one oil for use with engines, powershift transmissions, some hydraulics, and nonhypoid final drives. The obvious benefits would be reduced logistics and a significantly reduced potential for misapplication.
Other intended improvements include increased lubricant life and a 2- to 4-percent increase in fuel efficiency. A military-industry working group has been established to assist in this development, with the Army now conducting transmission and wet-brake tests on several current and experimental formulations.
The Army also has been actively contributing in the area of fuels technology. One example is the constant volume combustion bomb apparatus developed by SwRI for measuring the ignition qualities of fuels used in diesel engines. This recently approved technique has become ASTM D7170. The use of this new technology permits more rapid and accurate measuring of the cetane number than can be obtained with any of the existing cetane indexing methods.
The Army also has been actively involved in testing and validating alternative fuels. Although the Army has been using alternative fuels in its non-tactical fleets, it is currently participating in the Secretary of Defense’s Assured Fuels Initiative, which is designed to catalyze the industry to produce fuels for the military from domestic sources. Under this initiative, called the Joint Battlespace Use Fuel of the Future, the Army, Navy, and Air Force are working to develop fuel specifications; qualify the use of these fuels for all tactical vehicles and equipment, aircraft, and ships; and eventually provide a transition plan for Department of Defense-wide use of these unconventional fuels. The fuel currently being developed and evaluated is one produced from the gas-to-liquid process.
Many Army fuel initiatives created changes or new directions that were eventually assimilated by industry. One past member of the Engine Oil Reviewing Committee felt that the reviewing committee concept was the Army’s biggest contribution because it provided a stability factor that kept the performance levels of commercial automotive lubricants on an even playing field. The Army has contributed significantly in furthering the many technologies associated with automotive fuels and lubricants that have most certainly benefited industry.
Maurice E. Le Pera is a consultant for Le Pera and Associates of Harrisonburg, Virginia. He is a graduate of the University of Delaware and had 36 years of Government service. He is a member of the Society of Automotive Engineers, the Society of Tribologists and Lubrication Engineers, and the American Society for Testing and Materials.
The author wishes to acknowledge the contributions of Colonel Joseph John Volpe (1930–1995) during his tenure at the Army Quartermaster Center and School at Fort Lee, Virginia, from 1977 until his retirement in 1983. While at Fort Lee as a combat developer, Colonel Volpe was instrumental in promoting and actively supporting the needed funding for many of the research, development, test, and evaluation programs in fuels and lubricants that were subsequently conducted and mentioned in this article.