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Exhaust catalyst deactivation in small, handheld, 2-stroke engines is an issue that is faced quite frequently in efforts to improve or maintain catalyst performance but reduce cost. Fresh catalyst performance is rarely an issue, however, sustaining this performance for the specified useful life period of 50, 125, or 300 hours is where challenges start to arise. Our program goal was to develop and demonstrate a commercially viable catalyst which is capable of meeting regulatory and internal requirements with a deterioration factor (DF) near or below 1.0 over a 300 hour useful life period. A secondary objective was to utilize decreased quantities of platinum group metals (PGM) to reduce the cost relative to our reference catalyst. To achieve this, our focus was to reduce poisoning caused by exhaust byproducts and exhaust borne contaminants through a collaboration of catalyst advances and exhaust system design.

Until recently, U.S. government efforts to dramatically reduce emissions, greenhouse gases and vehicle fuel consumption have primarily focused on passenger car applications. Similar aggressive reductions need to be extended to heavy vehicles such as delivery trucks, buses, and motorhomes. However, the wide range of torques, speeds, and powers that such vehicles must operate under makes it difficult for any current powertrain system to provide the desired improvements in emissions and fuel economy. Hybrid electric powertrains provide the most promising, near-term technology that can satisfy these requirements. This paper highlights the configuration and benefits of a hybrid electric powertrain capable of operating in either a parallel or series mode. It describes the hybrid electric components in the system, including the electric motors, power electronics and batteries.

The National Automotive Center (NAC), part of the U.S. Army's Tank-automotive and Armaments Command (TACOM) and General Dynamics Land Systems have designed, fabricated and will demonstrate a series hybrid electric propulsion system integrated into a 20-ton Gross Vehicle Weight (GVW) 8×8 ground vehicle. The technologies of this vehicle, namely the Advanced Hybrid Electric Drive (AHED) Technology Demonstrator, may be candidates for inclusion into the automotive platform of the Future Combat Systems (FCS) ground vehicles. This paper discusses the logistical advantages of hybrid electric propulsion systems. It addresses fuel economy, technology maturity, platform commonality, and automotive performance as it relates to fighting, maintaining and supporting the FCS ground force.

Hybrid electric propulsion has matured to the point that it is in production for small vehicle platforms. Work still needs to be done on adapting the technology for heavier weight classes. The dramatic increase in fuel efficiency, the exhaust emission reductions and the availability of an on-board source of high-power electrical energy for auxiliary systems are important for the commercial and military market. The U.S. Army's National Automotive Center (NAC) in Warren, MI, and United Defense L.P. (UDLP) in San Jose, CA, have developed a series hybrid 20-ton tracked military vehicle to explore this technology. This paper describes this work and its application to the other hybrid programs.

This paper describes the approach taken by the U.S. Army Tank-automotive and Armaments Command (TACOM), Tank-automotive Research, Development and Engineering Center's (TARDEC) National Automotive Center (NAC) to attain practical fuel cell applications for military ground vehicle auxiliary power. This discussion covers the reasons for wanting military vehicle fuel cell Auxiliary Power Units (APUs), their potential role in the Army Transformation, the complications of applying fuel cells in military vehicles, concepts for military vehicle fuel cell APUs, and the NAC's commercial partnership strategy for fuel cell APU development.

This paper provides an overview of the Hybrid Electric Commercially Based Tactical Truck (COMBATT), a collaborative program between the U.S. Army Tank-automotive and Armaments Command's (TACOM) National Automotive Center (NAC) and the DaimlerChrysler Hybrid Electric Vehicle Platform Engineering Group. As part of the 21st Century Truck Initiative, the COMBATT platforms represent the class 2b (light) trucks. The platforms contain all of the utility and enhanced off-road capability features of the baseline COMBATT platform plus the second generation of a hybrid propulsion system incorporating an integral auxiliary power supply. The hybrid feature increases fuel efficiency, expands operational capability by providing a limited range electric propulsion mode, and enables an extended auxiliary electrical power supply capability. The auxiliary power supply provides up to 20kW of continuous electric power and 30kW of peak electric power for on- or off-board applications.

The U.S. Army's National Automotive Center has contracted with Illinois Institute of Technology Research Institute (IITRI), Southwest Research Institute (SwRI), and Advanced Propulsion, LLC, to evaluate the effects on fuel consumption and logistics that would result from hybridizing the powertrains of the Army's tactical wheeled vehicle fleet. This paper will outline the approach taken to perform that evaluation and present a synopsis of results achieved to date.

The study described in this paper covers the development of the Sequence IVB low-temperature valvetrain wear test as a replacement test platform for the existing ASTM D6891 Sequence IVA for the new engine oil category, ILSAC GF-6. The Sequence IVB Test uses a Toyota engine with dual overhead camshafts, direct-acting mechanical lifter valvetrain system. The original intent for the new test was to be a direct replacement for the Sequence IVA. Due to inherent differences in valvetrain system design between the Sequence IVA and IVB engines, it was necessary to alter existing test conditions to ensure adequate wear was produced on the valvetrain components to allow discrimination among the different lubricant formulations. A variety of test conditions and wear parameters were evaluated in the test development. Radioactive tracer technique (RATT) was used to determine the wear response of the test platform to various test conditions.

The effect of engine operating conditions on the formation of combustion chamber deposits has been studied by varying the driving cycle used in a series of vehicle tests aimed at measuring the CCD formation tendencies of different multifunctional fuel detergent additives. It was found that at higher engine temperatures it is not possible to easily differentiate the performance of different additives and that low load and low speed conditions should be chosen when testing additives for CCD control. The data obtained suggest that there is a direct correlation between the decomposition temperature of additive components as measured by thermogravimetric analysis (TGA) and their CCD formation tendencies. Of the various carrier fluids surveyed, materials based on alkyl oxides seem to perform the best in controlling CCD formation.

This paper presents experimental results of a 10.6L, three-cylinder opposed-piston (OP) operating on diesel fuel designed for heavy duty (Class 8) operation. The paper will describe the engine configuration and calibration of both catalyst light-off and high efficiency modes. Analysis based on measured results show the engine can comply with all 2027 California Air Resourced Board (CARB) and Environmental Protection Agency (EPA) requirements for CO2 and criteria emissions. Due to the ability of the OP Engine to combine low oxides of nitrogen (NOX) flux with high exhaust enthalpy for early catalyst light off, the engine can meet all 2027 CARB and EPA NOX standards with a current, state of the art conventional underfloor aftertreatment system. No additional emissions control technology is required.

An investigative group set up under the auspices of the CEC (Coordinating European Council) collected data on combustion chamber deposits (CCD), ASTM unwashed gum (UWG) results and the thermogravimetric analysis (TGA) of these gums for different fuels from many different sources. The analysis of this data shows that UWG cannot and does not predict CCD. It is not possible to use UWG or any aspect of its behaviour in the TGA to assess the CCD-forming tendency of randomly chosen fuels.

Deposits on engine parts, and in particular in combustion chambers of modern engines are causing increasing concern in the automobile industry. Highly sophisticated engine management systems make effects on emissions or performance obvious as outgassing of unburned hydrocarbons or variation of spark advance. Reduced mean heat flux away from the cylinder influences engine thermodynamics. Extreme deposits may cause noise increase by carbon rap. A special form of combustion chamber deposits, well known under the synonym spark plug fouling, is a carbon needle on spark plugs, which can cause the total damage of the catalysts (Japanese Industrial Standard D 1606: Adaptability Test Code of Spark Plug for Automobiles) The Co-ordinating European Council for the development of performance tests for transportation fuels, lubricants, and other fluids (CEC) started the development of a new performance test in 1994.

Hybrid electric propulsion is a viable, realistic, near-term technology that can dramatically increase the fuel efficiency of commercial and military ground vehicles. Hybrid vehicles also benefit from exhaust emission reductions and the availability of an on-board source of mobile high power electrical energy for auxiliary systems.

Modern natural gas-to-liquids (GTL) conversion processes (Fischer-Tropsch liquid fuels (FTL)) offers an attractive means for making synthetic liquid fuels. Military diesel and jet fuels are procured under Commercial Item Description (CID) A-A-52557 (based on ASTM D 975) and MIL-DTL-83133/MIL-DTL-5624 (JP-8/JP-5), respectively. The Single Fuel Forward (single fuel in the battlefield) policy requires the use of JP-8 or JP-5 (JP-8/5). Fuel properties crucial to fuel system/engine performance/operation are identified for both old and new tactical/non-tactical vehicles. The 21st Century Truck program is developing technology for improved safety, reduced harmful exhaust emissions, improved fuel efficiency, and reduced cost of ownership of future military and civilian ground vehicles (in the heavy duty category having gross vehicle weights exceeding 8500 pounds).[1]

To reach its objective of reducing vehicle fuel consumption by 50 percent, the development of the 21st Century Truck (21T) will address all the aspects of truck design contributing to the achievement of that goal. [1] This paper will address one of these aspects, specifically vehicle parasitic loss reduction with special emphasis on drive train losses, concentrating on the potential benefits of replacing mechanical coolant (water) and oil pumps with electrically powered pumps.

This paper will describe the Army's Vehicle Intelligence Program and discuss some of the VI technologies being considered for use within the Army's Tactical Wheeled Vehicle fleet. It will describe some initial modeling efforts that focus on the fuel efficiency impacts of selected VI technologies and will suggest the impacts of an integrated and networked fleet with regard to logistics. Lastly, it will identify several areas of AVIP research that are being considered in the near term. All of these programs impact directly on the 21st Century (21T) Truck program. [1]

Alternative fuels made from materials other than petroleum are available for use in alternative fueled vehicles (AFVs) and some conventional vehicles. Liquid fuels such as biodiesel could be used in U.S. Army or other Military/Federal Government compression ignition (CI) engine powered vehicles. The military combat/tactical fleet is exempt from Federal Government mandates to use alternative fueled vehicles and has adopted JP-8/JP-5 jet fuel as the primary military fuel. The Army non-tactical fleet and other Federal nonexempt CI engine powered vehicles are possible candidates for using biodiesel. Inclusion of biodiesel as an alternative fuel qualifying for alternative fueled vehicle credits for fleets required to meet AFV requirements has allowed for its use at 20 (minimum) percent biodiesel in petroleum diesel fuel. Alternative fuels are being considered for the 21st Century Truck (21T) program. [1]

“Zoning” a catalytic converter involves placing higher concentrations of platinum group metals (PGM) in the inlet portion of the substrate. This is done to optimize the cost-to-performance tradeoff by increasing the reaction rate at lower temperatures while minimizing PGM usage. A potentially useful application of catalyst zoning is to improve performance using a constant PGM mass. A study was performed to assess what the optimum ratio of front to rear palladium zone length is to achieve the highest performance in vehicle emission testing. Varying the zone ratio from 1:1 to 1:9 shows a clear hydrocarbon performance optimum at a 1:5.66 (15%/85%) split. This performance optimum shows as both a minimum in FTP75 non-methane organic gas (NMOG) emissions as well as a minimum in hydrocarbon, carbon monoxide, and nitrogen oxide light-off temperature. Overall, an improvement of 18%, or 11 mg/mi of combined NMOG+NOx emissions was obtained without using additional PGM.

The U.S. Environmental Protection Agency (EPA) certifies gasoline deposit control additives for intake valve deposit (IVD) control utilizing ASTM D5500, a vehicle test using a1985 BMW 318i. Concerns with the age of the test fleet, its relevance in the market today, and the availability of replacement parts led the American Chemistry Council’s (ACC) Fuel Additive Task Group (FATG) to begin a program to develop a replacement. General Motors suggested using a 2.4L LE9 test engine mounted on a dynamometer and committed to support the engine until 2030. Southwest Research Institute (SwRI®) was contracted to run the development program in four Phases. In Phase I, the engine test stand was configured, and a test fuel selected. In Phase II, a series of tests were run to identify a cycle that would build an acceptable level of deposits on un-additized fuel. In Phase III, the resultant test cycle was examined for repeatability.