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Technical Paper

Measuring Diesel Emissions with a Split Exhaust Configuration

2001-05-07
2001-01-1949
West Virginia University evaluated diesel oxidation catalysts (DOC) and lean-NOX catalysts as part of Diesel Emissions Control-Sulfur Effects (DECSE) project. In order to perform thermal aging of the DOC and lean-NOX catalysts simultaneously and economically, each catalyst was sized to accommodate half of the engine exhaust flow. Simultaneous catalyst aging was then achieved by splitting the engine exhaust into two streams such that approximately half of the total exhaust flowed through the DOC and half through the lean-NOX catalyst. This necessitated splitting the engine exhaust into two streams during emissions measurements. Throttling valves installed in each branch of the split exhaust were adjusted so that approximately half the engine exhaust passed though the active catalyst under evaluation and into a full flow dilution tunnel for emissions measurement.
Technical Paper

The Development of a Fourth Generation Hybrid Electric Vehicle at West Virginia University

2001-03-05
2001-01-0682
As a part of the FutureTruck 2000 advanced technology student vehicle competition sponsored by the US Department of Energy and General Motors, West Virginia University has converted a full-size sport utility vehicle into a high fuel efficiency, low emissions vehicle. The environmental impact of the Chevrolet Suburban SUV, in terms of both greenhouse gas emissions and exhaust emissions, was reduced through hybridization without losing any of the functionality and utility of the base vehicle. The approach taken was one of using a high efficiency, state-of-the-art direct injection, turbocharged diesel engine coupled to a high output electric traction motor for power assist and to recover regenerative braking energy. The vehicle employs a state-of-the-art combination lean NOx catalyst, oxidation catalyst and particulate filter to ensure low exhaust emissions.
Technical Paper

2000 University of Maryland FutureTruck Design Description

2001-03-05
2001-01-0681
The University of Maryland team converted a model year 2000 Chevrolet Suburban to an ethanol-fueled hybrid-electric vehicle (HEV) and tied for first place overall in the 2000 FutureTruck competition. Competition goals include a two-thirds reduction of greenhouse gas (GHG) emissions, a reduction of exhaust emissions to meet California ultra-low emissions vehicle (ULEV) Tier II standards, and an increase in fuel economy. These goals must be met without compromising the performance, amenities, safety, or ease of manufacture of the stock Suburban. The University of Maryland FutureTruck, Proteus, addresses the competition goals with a powertrain consisting of a General Motors 3.8-L V6 engine, a 75-kW (100 hp) SatCon electric motor, and a 336-V battery pack. Additionally, Proteus incorporates several emissions-reducing and energy-saving modifications; an advanced control strategy that is implemented through use of an on-board computer and an innovative hybrid-electric drive train.
Technical Paper

The Coaxial Cavity Resonator as a RF IC Engine Ignition Source

2001-03-05
2001-01-0987
The Quarter Wave Coaxial Cavity Resonator (QWCCR) plasma igniter is designed, from previous theoretical work, as an ignition source for an internal combustion engine. The present research has explored the implementation of the QWCCR into an internal combustion (IC) engine. The QWCCR design parameters of inner conductor length, loop geometry, and loop position were varied for two igniters of differing operating frequency. Variations of the QWCCR radio frequency (RF) parameters, as a function of engine geometry, were studied by placing the igniter in a combustion chamber and manually varying the crank position. Three identical igniters were fitted with dielectric inserts and the parameters were studied before and after ignition was sustained in a twin-cylinder engine. Optimal resonator geometries were determined. Radio frequency parameter invariance was found with respect to crank angle and piston distance. The first successful IC engine ignition using a QWCCR was achieved.
Technical Paper

Knock Prediction in Reciprocating Gas-Engines Using Detailed Chemical Kinetics

2001-03-05
2001-01-1012
Two and three-dimensional test cases were simulated using a detailed kinetic mechanism for di-methyl ether to represent methane combustion. A piston-bowl assembly for the compression and expansion strokes with combustion has been simulated at 1500 RPM. A fine grid was used for the 2-D simulations and a rather coarse grid was used for the 3-D calculations together with a k-ε subgrid-scale turbulence model and a partially stirred reactor model with three time scales. Ignition was simulated artificially by increasing the temperature at one point inside the cylinder. The results of these simulations were compared with experimental results. The simulation involved an engine with a homogeneous charge of methane as fuel. Results indicate that pressure fluctuations were captured some time after the ignition started, which indicates knock conditions.
Technical Paper

Towards Optimization of Automotive Waste Heat Recovery Using Thermoelectrics

2001-03-05
2001-01-1021
The potential for thermoelectric power generation via waste heat recovery onboard automobiles to displace alternators and/or provide additional charging to a hybrid vehicle battery pack has increased with recent advances in thermoelectric materials processing. A preliminary design/modeling study was performed to optimize waste heat recovery for power generation using a modified radiator incorporating thermoelectric modules. The optimization incorporates not only thermoelectric performance but also critical systems issues such as accessory power consumption, vehicle drag, and added system weight. Results indicate the effectiveness of the thermoelectric module is extremely sensitive to ambient heat rejection and to the operating temperature range of the thermoelectric device.
Technical Paper

Quantification of Muscle Fatigue and Joint Position of the Hand During EVA Simulation Operations

1997-07-01
972322
Task-based intensity and fatigue metrics were developed and applied to neutral buoyancy simulations of extravehicular activities (EVA). Surface electromyographic (EMG) signals from hand flexor and extensor musculature were recorded during neutral buoyancy EVA simulations at Marshall Space Flgiht Center (MSFC) in August-September 1996. A task intensity index, based on the cumulative histogram of EMG amplitude, was developed and used to determine relative physical difficulty of handgripping, knob turning, bolt manipulation, and j-hook release tasks. A fatigue index, based on the task intensity metric and task duration, was used to provide a measure of task-related fatigue.
Technical Paper

Development of a Power-Assisted Space Suit Glove Joint

1997-07-01
972323
The need for improvement of EVA gloves has been identified by NASA and the user community. Particularly important, especially for near to long term goals in the space program, is the need to reduce the fatigue associated with manual tasks. The University of Maryland Space Systems Laboratory (SSL), together with ILC Dover are currently developing an unobtrusive, power-assisted EVA glove that will attempt to provide a suited crewperson with as close to nude-body hand dexterity as possible. The power-assisted joint is designed to provide sufficient force to offset the resistance of the pressurized glove itself, thus alleviating manual fatigue, but provides no additional strength augmentation. This paper describes the initial prototype power-assist mechanism which has been developed, reviewing the relevant design issues and discussing the initial test results from the prototype.
Technical Paper

Modularity in Spark Ignition Engines: A Review of its Benefits, Implementation and Limitations

1998-10-19
982688
A conceptual understanding of modularity in internal combustion engines (defined as design, operation, and sensing on an individual cylinder basis) is presented. Three fundamental modular concepts are identified. These are dissimilar component sizing and operation, component deactivation, and direct sensing. The implementation of these concepts in spark ignition internal combustion engines is presented. Several modular approaches are reviewed with respect to breathing, fueling, power generation, and sensing. These include dissimilar orientation, geometry, and activation of multiple induction runners, partial or total disablement of valves through direct or indirect means, dissimilar fueling of individual cylinders, skipping the combustion event of one or more cylinders, deactivation of dissimilar individual cylinders or a group of cylinders, and individual cylinder gas pressure and mixture strength sensing.
Technical Paper

Design and Preliminary Test Results from a Second Generation Power-Assisted Space Suit Glove Joint

1998-07-13
981674
Near to long term goals in the nation's space program would benefit from a significant reduction of the fatigue associated with manual tasks performed by suited astronauts, and the corresponding increase in the comfort, safety, and productivity of EVA operations this would enable. To this end, the University of Maryland Space Systems Laboratory and ILC Dover Inc. have developed an electromechanical, power-assisted EVA glove which has demonstrated the ability to substantially reduce manual fatigue while simultaneously increasing range of motion. The lessons learned from the construction and testing of this initial prototype have been used to guide a second generation design for this power-assist concept, which achieves comparable or superior performance with significantly less hardware and power consumption. This paper describes the new, second generation power-assist mechanism, reviewing the relevant design issues and comparing its performance with the initial design.
Technical Paper

Exhaust Gas Recirculation in a Lean-Burn Natural Gas Engine

1998-05-04
981395
Lean-burn natural gas engines offer attractively low particulate matter emissions and enjoy higher efficiencies than their stoichiometric counterparts. However, even though oxides of nitrogen emissions can be reduced through operation at lambda ratios of greater than 1.3, catalysts cannot reduce the oxides of nitrogen emissions in the oxidizing exhaust environment. Exhaust Gas Recirculation (EGR) offers the potential to reduce engine out oxides of nitrogen emissions by reducing the flame temperature and oxygen partial pressure that encourages their formation during the combustion process. A comparative study involving a change in the nature of primary diluent (air replaced by EGR) in the intake of a Hercules, 3.7 liter, lean-burn natural gas engine has been undertaken in this research. The Hercules engine was equipped with a General Motors electronically controlled EGR valve for low EGR rates, and a slide valve, constructed in house, for high EGR rates.
Technical Paper

Emissions from Trucks and Buses Powered by Cummins L-10 Natural Gas Engines

1998-05-04
981393
Both field research and certification data show that the lean burn natural gas powered spark ignition engines offer particulate matter (PM) reduction with respect to equivalent diesel power plants. Concerns over PM inventory make these engines attractive despite the loss of fuel economy associated with throttled operation. Early versions of the Cummins L-10 natural gas engines employed a mixer to establish air/fuel ratio. Emissions measurements by the West Virginia University Transportable Heavy Duty Emissions Testing Laboratories on Cummins L-10 powered transit buses revealed the potential to offer low emissions of PM and oxides of nitrogen, (NOx) but variations in the mixture could cause emissions of NOx, carbon monoxide and hydrocarbons to rise. This was readily corrected through mixer repair or readjustment. Newer versions of the L-10 engine employ a more sophisticated fueling scheme with feedback control from a wide range oxygen sensor.
Technical Paper

Alternative Fuel Truck Evaluation Project - Design and Preliminary Results

1998-05-04
981392
The objective of this project, which is supported by the U.S. Department of Energy (DOE) through the National Renewable Energy Laboratory (NREL), is to provide a comprehensive comparison of heavy-duty trucks operating on alternative fuels and diesel fuel. Data collection from up to eight sites is planned. This paper summarizes the design of the project and early results from the first two sites. Data collection is planned for operations, maintenance, truck system descriptions, emissions, duty cycle, safety incidents, and capital costs and operating costs associated with the use of alternative fuels in trucking.
Technical Paper

Numerical Prediction of Knock in a Bi-Fuel Engine

1998-10-19
982533
Dedicated natural gas engines suffer the disadvantages of limited vehicle range and relatively few refueling stations. A vehicle capable of operating on either gasoline or natural gas allows alternative fuel usage without sacrificing vehicle range and mobility. However, the bi-fuel engine must be made to provide equal performance on both fuels. Although bi-fuel conversions have existed for a number of years, historically natural gas performance is degraded relative to gasoline due to reduced volumetric efficiency and lower power density of CNG. Much of the performance losses associated with CNG can be overcome by increasing the compression ratio. However, in a bi-fuel application, high compression ratios can result in severe engine knock during gasoline operation. Variable intake valve timing, increased exhaust gas recirculation and retarded ignition timing were explored as a means of controlling knock during gasoline operation of a bi-fuel engine.
Technical Paper

A Long Term Field Emissions Study of Natural Gas Fueled Refuse Haulers in New York City

1998-10-19
982456
New York City Department of Sanitation has operated natural gas fueled refuse haulers in a pilot study: a major goal of this study was to compare the emissions from these natural gas vehicles with their diesel counterparts. The vehicles were tandem axle trucks with GVW (gross vehicle weight) rating of 69,897 pounds. The primary use of these vehicles was for street collection and transporting the collected refuse to a landfill. West Virginia University Transportable Heavy Duty Emissions Testing Laboratories have been engaged in monitoring the tailpipe emissions from these trucks for seven-years. In the later years of testing the hydrocarbons were speciated for non-methane and methane components. Six of these vehicles employed the older technology (mechanical mixer) Cummins L-10 lean burn natural gas engines.
Technical Paper

Interface Design Issues of the Ranger Telerobotics Flight Experiment

1995-07-01
951522
While robotics have been employed in many environments, their use in space has been limited by high development costs and reliability issues. Using new management strategies and reduced mission life, the University of Maryland and NASA are developing the Ranger Telerobotic Flight Experiment (TFX), scheduled for flight in early 1997. This mission poses unique requirements on the design and implementation of the ground control station and it's interfaces. Two of the most important design issues are the need for high bandwidth command data, and cost constraints on the operator interface. This paper is intended to briefly outline the Ranger TFX mission, related theory on human perception, capabilities the control station must supply to vehicle designers sot that they can design effective control station interfaces, results from a preliminary study, and suggestions for future research.
Technical Paper

Enumeration of Epicyclic-Type Automatic Transmission Gear Trains

1994-03-01
941012
An automotive transmission maintains a proper equilibrium between the power and torque produced by an engine and those demanded by the drive wheels. Most automatic, transmissions employ some kind of epicyclic gear mechanisms to achieve the above purpose. The first step in the design process of such a mechanism involves finding a configuration that provides a set of desired speed ratios, and meets other dynamic, and kinematic requirements. In this work, the kinematic structural characteristics of epicyclic gear mechanisms have been identified, and a methodology is formulated to systematically enumerate all possible configurations of such mechanisms. This is achieved by defining a canonical graph to represent the mechanisms. Graphs of mechanisms with up to ten links have been generated using this methodology.
Technical Paper

A Methodology for Enumeration of Clutching Sequences Associated with Epicyclic-Type Automatic Transmission Mechanisms

1996-02-01
960719
This paper presents a systematic methodology for the enumeration of clutching sequences associated with epicyclic-gear-type automatic transmission mechanisms. The methodology is based on the concept that an epicyclic gear mechanism can be decomposed into several fundamental geared entities and that the overall speed ratio of an epicyclic gear mechanism can be symbolically expressed in terms of its fundamental geared entities. First, a procedure for estimating the overall speed ratio of an epicyclic gear mechanism, without specifying the exact gear dimensions, is outlined. Then, an algorithm for comparing various possible speed ratios of an epicyclic gear mechanism is described. Finally, a methodology for systematically enumerating all possible clutching sequences of an epicyclic gear mechanism is established.
Technical Paper

Effect of Exit Plane Boundary Conditions on Time Accurate Computations

1997-02-24
970140
Effects of boundary conditions on the computational simulation of time dependent flows is studied. In particular, the effect of various boundary conditions for the flow over a half circular cylinder which is known to exhibit periodic shedding under certain conditions is investigated. A type of convection boundary condition called the radiation boundary condition is demonstrated to eliminate the secondary frequency which contaminates the solution due to the partial reflection of the fluid structures at the exit plane. However, the boundary condition implementation comes at the additional cost of storing results corresponding to three time levels.
Technical Paper

A Parametric Study of Knock Control Strategies for a Bi-Fuel Engine

1998-02-23
980895
Until a proper fueling infrastructure is established, vehicles powered by natural gas must have bi-fuel capability in order to avoid a limited vehicle range. Although bi-fuel conversions of existing gasoline engines have existed for a number of years, these engines do not fully exploit the combustion and knock properties of both fuels. Much of the power loss resulting from operation of an existing gasoline engine on compressed natural gas (CNG) can be recovered by increasing the compression ratio, thereby exploiting the high knock resistance of natural gas. However, gasoline operation at elevated compression ratios results in severe engine knock. The use of variable intake valve timing in conjunction with ignition timing modulation and electronically controlled exhaust gas recirculation (EGR) was investigated as a means of controlling knock when operating a bi-fuel engine on gasoline at elevated compression ratios.
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