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RADIATION can produce almost instantaneous failure of modern aircraft lubricants, tests at Southwest Research Institute show. Two types of failures demonstrated are rapid viscosity rise and loss of heat conductivity. Furthermore, it was found that lubricants can become excessively corrosive under high-level radiation. Generally speaking, the better lubricants appeared to improve in performance while marginal ones deteriorated to a greater extent under radiation. When the better lubricants were subjected to static irradiation prior to the deposition test, there was a minor increase in deposition number as the total dose was increased.

The use of alcohol as a supplemental fuel for a medium-speed diesel engine was investigated using a two-cylinder, two-stroke test engine. Both stabilized and unstabilized emulsions of methanol-in-diesel fuel and ethanol-in-diesel fuel were tested. Also, anhydrous ethanol/diesel fuel solutions were evaluated. Maximum alcohol content of the emulsions and solutions was limited by engine knocking due to a reduction in fuel cetane number. Engine power and thermal efficiency were slightly below baseline diesel fuel levels in the high and mid-speed ranges, but were somewhat improved at low speeds during tests of the unstabilized emulsions and the ethanol solutions. However, thermal efficiency of the stabilized emulsions fell below baseline levels at virtually all conditions.

Comparative emission measurements were made in two dynamometer-based diesel engines using protocol specified by the U.S. Environmental Protection Agency (EPA) and the California Air Resources Board (CARB). A single JP-8 fuel with a sulfur level of 0.06 weight percent (wt%) was adjusted to sulfur levels of 0.11 and 0.26 wt%. The emission characteristics of the three fuels were compared to the 1994 EPA certification low-sulfur diesel fuel (sulfur level equal to 0.035 wt%) in the Detroit Diesel Corporation (DDC) 1991 prototype Series 60 diesel engine and in the General Motors (GM) 6.2L diesel engine. Comparisons were made using the hot-start transient portion of the heavy-duty diesel engine Federal Test Procedure. Results from the Army study show that the gaseous emissions for the DDC Series 60 engine using kerosene-based JP-8 fuel are equivalent to values obtained with the 0.035 wt% sulfur EPA certification diesel fuel.

The use of compressed natural gas as an alternative to conventional fuels has received a great deal of attention as a strategy for reducing air pollution from motor vehicles. In many cases, regulatory action has been taken to displace diesel fuel with natural gas in truck and bus applications. Emissions results of heavy-duty transient FTP testing of two Cummins L10-240G natural gas engines are presented. Regulated emissions of non-methane hydrocarbons, total hydrocarbons, CO, NOx, and particulate were characterized, along with emissions of formaldehyde. The effects of air/fuel ratio adjustments on these emissions were explored, as well as the effectiveness of catalytic aftertreatment in reducing exhaust emissions. Compared to typical heavy-duty diesel engine emissions, CNG-fueled engines using exhaust aftertreatment have great potential for meeting future exhaust emission standards, although in-use durability is unproven.

A project was conducted by Southwest Research Institute on behalf of the California Air Resources Board and the South Coast Air Quality Management District to demonstrate the technical feasibility of utilizing closed-loop three-way catalyst technology in off-road equipment applications. Five representative engines were selected, and baseline emission-tested using both gasoline and LPG. Emission reduction systems, employing three-way catalyst technology with electronic fuel control, were designed and installed on two of the engines. The engines were then installed in a fork lift and a pump system, and limited durability testing was performed. Results showed that low emission levels, easily meeting CARB's newly adopted large spark-ignited engine emission standards, could be achieved.

A new approach to reclaiming the spoil areas produced by area-type mining operations has been developed. This system uses a machine known as a winch-dozer, consisting of a pair of large back-to-back buckets which are drawn by cable across spoil piles, moving back and forth between a “tailblock” anchor and a “drawworks” winch unit developed as an attachment to a large crawler tractor. The system is expected to reduce the cost of reclamation leveling by 40-50%. The system permits more effective power utilization due to the blade system's light weight, induces caving of spoil banks, and permits moving spoil in both directions of blade travel.

Radioactive tracer technology is an important tool for measuring component wear on a real-time basis and is especially useful in measuring engine wear as it is affected by combustion system operation and lubricant performance. Combustion system operation including the use of early and/or late fuel injection and EGR for emissions control can have a profound effect on aftertreatment contamination and engine reliability due to wear. Liner wear caused by localized fuel impingement can lead to excessive oil consumption and fuel dilution can cause excessive wear of rings and bearings. To facilitate typical wear measurement, the engine's compression rings and connecting rod bearings are initially exposed to thermal neutrons in a nuclear reactor to produce artificial radioisotopes that are separately characteristic of the ring and bearing wear surfaces.

Radioactive tracer technology (RAT) is an important tool in measuring component wear in an operating engine on a real-time basis. This paper will discuss the use of RAT to study and evaluate boundary lubricant and surfactant chemistries aimed at providing benefits in wear control. In particular, RAT was employed to study ring and bearing wear as a function of engine operating condition (speed, load, and temperature) and lubricant characteristics. Prior to testing, the engine's compression rings and connecting rod bearings were subjected to bulk thermal neutron bombardment in a nuclear reactor to produce artificial radioisotopes that were separately characteristic of the ring and bearing wear surfaces. The irradiated parts were installed in the test engine, after which testing to a specific test matrix was accomplished.

The Texas Department of Transportation (TxDOT) began using an ultra-low-sulfur, low aromatic, high cetane number diesel fuel (TxLED, Texas Low Emission Diesel) in June 2003. They initiated a simultaneous study of the effectiveness to reduce emissions and influence fuel economy of this fuel in comparison to 2D on-road diesel fuel used in both their on-road and off-road equipment. The study incorporated analyses for the fleet operated by the Association of General Contractors (AGC) in the Houston area. Some members of AGC use 2D off-road diesel in their equipment. One off-road engine, two single-axle dump trucks, and two tandem-axle dump trucks were tested. The equipment tested included newer electronically-controlled diesels. The off-road engine was tested over the TxDOT Telescoping Boom Excavator Cycle. The dump trucks were tested using the “route” technique over the TxDOT Single-Axle Dump Truck Cycle or the TxDOT Tandem-Axle Dump Truck Cycle.

The Texas Department of Transportation began using an emulsified diesel fuel in 2002. They initiated a simultaneous study of the effectiveness of this fuel in comparison to 2D on-road diesel fuel and 2D off-road diesel. The study included comparisons of fuel economy and emissions for the emulsion, Lubrizol PuriNOx®, relative to conventional diesel fuels. Two engines and eight trucks, four single-axle dump trucks, and four tandem-axle dump trucks were tested. The equipment tested included both older mechanically-controlled diesels and newer electronically-controlled diesels. The two engines were tested over two different cycles that were developed specifically for this project. The dump trucks were tested using the “route” technique over one or the other of two chassis dynamometer cycles that were developed for this project In addition to fuel efficiency, emissions of NOx, PM, CO, and HCs were measured. Additionally, second-by-second results were obtained for NOx and HCs.

The Texas Department of Transportation (TxDOT) began using an emulsified diesel fuel in July 2002. They initiated a simultaneous study of the effectiveness of this fuel in comparison to 2D on-road diesel fuel, which they use in both their on-road and off-road equipment. The study also incorporated analyses for the fleet operated by the Associated General Contractors (AGC) in the Houston area. Some members of AGC use 2D off-road diesel fuel in their equipment. The study included comparisons of fuel economy and emissions for the emulsified fuel relative to the conventional diesel fuels. Cycles that are known to be representative of the typical operations for TxDOT and AGC equipment were required for use in this study. Four test cycles were developed from data logged on equipment during normal service: 1) the TxDOT Telescoping Boom Excavator Cycle, 2) the AGC Wheeled Loader Cycle, 3) the TxDOT Single-Axle Dump Truck Cycle, and 4) the TxDOT Tandem-Axle Dump Truck Cycle.

SwRI has developed a new technology concept involving the use of high EGR rates coupled with a high-energy ignition system in a gasoline engine to improve fuel economy and emissions. Based on a single-cylinder study [1], this study extends the concept of a high compression ratio gasoline engine with EGR rates > 30% and a high-energy ignition system to a multi-cylinder engine. A 2000 MY Isuzu Duramax 6.6 L 8-cylinder engine was converted to run on gasoline with a diesel pilot ignition system. The engine was run at two compression ratios, 17.5:1 and 12.5:1 and with two different EGR systems - a low-pressure loop and a high pressure loop. A high cetane number (CN) diesel fuel (CN=76) was used as the ignition source and two different octane number (ON) gasolines were investigated - a pump grade 91 ON ((R+M)/2) and a 103 ON ((R+M)/2) racing fuel.

The engine selected for this work was a Caterpillar 3176 engine. Engine exhaust emissions, performance, and heat release rates were measured as functions of engine configuration, engine speed and load. Two engine configurations were used, a standard 1994 design and a 1994 configuration with EGR designed to achieve a NOx emissions level of 2.5 gm/hp-hr. Measurements were performed at 7 different steady-state, speed-load conditions on thirteen different test fuels. The fuel matrix was statistically designed to independently examine the effects of the targeted fuel properties. Cetane number was varied from 40 to 55, using both natural cetane number and cetane percent improver additives. Aromatic content ranged from 10 to 30 percent in two different forms, one in which the aromatics were predominantly mono-aromatic species and the other, where a significant fraction of the aromatics were either di- or tri-aromatics.

Fuel additives are being used more frequently to meet “premium diesel fuel” requirements. Although these additives improve performance, they also affect the water separation characteristics. This program was designed to determine the effects of various additives on fuel/water separation in low- and ultra-low sulfur diesel fuel. The additives studied include detergents and lubricity additives. A soy-based biofuel is also considered. The fuel/water separation tests conducted with coalescer filter technology generally produced higher efficiencies while the addition of a detergent additive package at 175-ppm generally produced lower water separation efficiencies.

The use of biodiesel fuels derived from vegetable oils or animal fats as a substitute for conventional petroleum fuel in diesel engines has received increased attention. This interest is based on a number of properties of biodiesel including the fact that it is produced from a renewable resource, its biodegradability, and its potential beneficial effects on exhaust emissions. As part of Tier 1 compliance requirements for EPA's Fuel Registration Program, a detailed chemical characterization of the transient exhaust emissions from three modern diesel engines was performed, both with and without an oxidation catalyst. This characterization included several forms of hydrocarbon speciation, as well as measurement of aldehydes, ketones, and alcohols. In addition, both particle-phase and semivolatile-phase PAH and nitro-PAH compounds were measured. Unregulated emissions were characterized with neat biodiesel and with a blend of biodiesel and conventional diesel fuel.

The use of biodiesel fuels derived from vegetable oils or animal fats as a substitute for conventional petroleum fuel in diesel engines has received increased attention. This interest is based on a number of properties of biodiesel including the fact that it is produced from a renewable resource, its biodegradability, and its potential beneficial effects on exhaust emissions. Transient exhaust emissions from three modern diesel engines were measured during this study, both with and without an oxidation catalyst. Emissions were characterized with neat biodiesel and with a blend of biodiesel and conventional diesel fuel. Regulated emissions and performance data are presented in this paper, while the results of a detailed chemical characterization of exhaust emissions are presented in a companion paper. The use of biodiesel resulted in lower emissions of unburned hydrocarbons, carbon monoxide, and particulate matter, with some increase in emissions of oxides of nitrogen on some engines.

Several techniques have been developed to measure the relative amount of splash and spray produced by vehicles when driven on wet roads at highway speeds under controlled conditions. This paper discusses considerations in the development of measurement techniques such as those utilizing photographs, a photometer, densitometer, spraymeter, and spray collector. The development of each technique is described. Some test data utilizing the photometer and densitometer techniques are presented in a comparison of two different trucks run on two different road surfaces with new and worn tires, fully loaded and unloaded, and under light and heavy road moisture conditions.

A technology demonstration program was conducted by the U.S. Army to verify the feasibility of using aviation turbine fuel JP-8 in all military diesel fuel-consuming ground vehicles and equipment (V/E). Over 2,800 pieces of military equipment participated in a two and one-half year program accumulating over 2,621,000 total miles (4,219,810 km) using JP-8 in combat/tracked, tactical/wheeled, and transportation motor pool vehicles. Over 71,000 hours of operation were accumulated in diesel/turbine engine-driven generator sets using JP-8 fuel. Comparisons of various performance areas with baseline diesel fuel (DF-2) operation were made.

A heavy duty (150 kW) diesel engine was tested to determine operational problems while running on minimally processed synthetic fuels. A reference No. 2 diesel fuel was compared with liquid products derived from shale, tar sands, and coal. Information on the engine setup and test procedure is presented. The test results include engine power, thermal efficiency, ignition delay, gaseous and particulate emissions, smoke opacity, cylinder pressure, and heat release data. Cold start data at 0°C and −20° C and idle deposit test results are also presented. These data should help to determine future engine modifications to enhance synfuel engine performance.

In support of the Department of Defense goal to streamline procurements, the Army recently decided to discontinue use of VV-F-800D as the purchase specification for diesel fuel being supplied to continental United States military installations. The Army will instead issue a commercial item description for direct fuel deliveries under the Post-Camp-Station (PCS) contract bulletin program. In parallel, the Defense Fuel Supply Center and the U.S. Army Mobility Technology Center-Belvoir (at Ft. Belvoir, VA) initiated a fuel survey with the primary objective to assess the general quality and lubricity characteristics of low sulfur diesel fuels being supplied to military installations under the PCS system. Under this project, diesel fuel delivery samples were obtained from selected military installations and analyzed according to a predetermined protocol.