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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.

The U.S. Army currently uses JP-8 for global operations according to the ‘one fuel forward policy’ in order to reduce the logistics burden of supplying a variety of fuels for given Department of Defense ground vehicle applications. One particular challenge with using global JP-8 is the lack of or too broad a range of specified combustion affecting properties including ignition quality, high temperature viscosity, and density. In particular, the ignition quality of JP-8 has dramatically varied throughout the past decade on a global basis covering a range of 29 to 70 cetane index. This key combustion affecting parameter was explored in this study by evaluating a synthesized low ignition quality jet fuel blended in 25% volumetric proportions with JP-8 to effectively cover a cetane number range of 25 to 45 in a single cylinder diesel engine operated at various light, medium, and high load operating conditions.

The US Army is currently seeking to reduce fuel consumption by utilizing fuel efficient lubricants in its ground vehicle fleet. An additional desire is for a lubricant which would consist of an all-season (arctic to desert), fuel efficient, multifunctional Single Common Powertrain Lubricant (SCPL) with extended drain capabilities. To quantify the fuel efficiency impact of a SCPL type fluid in the engine and transmission, current MIL-PRF-46167D arctic engine oil was used in place of MIL-PRF-2104G 15W-40 oil and SAE J1321 Fuel Consumption In-Service testing was conducted. Additionally, synthetic SAE 75W-140 gear oil was evaluated in the axles of the vehicles in place of an SAE J2360 80W-90 oil. The test vehicles used for the study were three M1083A1 5-Ton Cargo vehicles from the Family of Medium Tactical Vehicles (FMTV).

The US Army is currently assessing the feasibility and defining the requirements of a Single Common Powertrain Lubricant (SCPL). This new lubricant would consist of an all-season (arctic to desert), fuel-efficient, multifunctional powertrain fluid with extended drain capabilities. As a developmental starting point, diesel engine testing has been conducted using the current MIL-PRF-46167D arctic engine oil at high temperature conditions representative of desert operation. Testing has been completed using three high density military engines: the General Engine Products 6.5L(T) engine, the Caterpillar C7, and the Detroit Diesel Series 60. Tests were conducted following two standard military testing cycles; the 210 hr Tactical Wheeled Vehicle Cycle, and the 400 hr NATO Hardware Endurance Cycle. Modifications were made to both testing procedures to more closely replicate the operation of the engine in desert-like conditions.

This paper presents a new approach for the development of six different JP-8 surrogates for application in diesel cycle simulation. The approach involves a step-wise formulation of 2-, 3-, and 4-component surrogates from a list of pure compounds which are selected based on several criteria. A MATLAB code is developed and is used in conjunction with the Ignition Quality Tester (IQT) and HYSYS software in order to formulate optimal surrogates. The first part of the results shows a comparison between the calculated and the measured DCNs for six surrogates. The differences in the properties such as the density, volatility, lower heating value, H/C ratio, molecular weight, and threshold sooting index of the surrogates and the JP-8 are also highlighted. This is followed by the evaluation of the surrogates with respect to the target JP-8 fuel. The evaluation is made in terms of ignition delays and the rate of heat release at three different IQT test temperatures.