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Partially premixed low temperature combustion (LTC) in diesel engines is a strategy for reducing soot and NOX formation, though it is accompanied by higher unburned hydrocarbon (UHC) emissions compared to conventional mixing-controlled diesel combustion. In this work, two independent methods of quantifying light UHC species from a diesel engine operating in early LTC (ELTC) modes were compared: Fourier transform infrared (FT-IR) spectroscopy and gas chromatography-mass spectroscopy (GC-MS). A sampling system was designed to capture and transfer exhaust samples for off-line GC-MS analysis, while the FT-IR sampled and quantified engine exhaust in real time. Three different ELTC modes with varying levels of exhaust gas recirculation (EGR) were implemented on a modern light-duty diesel engine. GC-MS and FT-IR concentrations were within 10 % for C2H2, C2H4, C2H6, and C2H4O. While C3H8 was identified and quantified by the FT-IR, it was not detected by the GCMS.

The shortened liquid cooling/warming garment (SLCWG) developed by the University of Minnesota group was compared with the standard NASA liquid cooling/ventilating garment (LCVG) garment during physical exertion in comfort (24°C) and hot (35°C) chamber environments. In both environmental conditions, the SLCWG was just as effective as the LCVG in maintaining rectal temperature (Tre) in a thermal comfort range; sweat production on the face was less; and subjective perception of overall and local body comfort was higher. The findings indicate that the SLCWG produces the same or greater comfort level as that achieved with the LCVG's total coverage of the body surface.

Control of vehicular platoons has been a problem of interest in the controls domain for the past 40 years. This problem gained a lot of popularity when the California PATH (Partners for Advanced Transportation Technology) program was operational. String stability is an important design criterion in this problem and it has been shown that lead vehicle information is essential to achieve it. This work builds upon the existing framework and presents a controller form for each follower in the string where the lead vehicle information is used explicitly to analytically demonstrate string stability. The discussion is focused on using information from immediate neighbors to achieve string stability. Recent developments in distributed control are an attractive framework for control design where each agent has access to states of the neighbors and not all agents in the network. In this work, the aim is to design sparse H2 controllers and then perform a check on string stability.

A series of demonstration studies were conducted with the aim of better understanding how to regulate body heat and thus enhance thermal comfort of astronauts during EVA requiring intensive physical exertion. The first study evaluated body zone heat transfer under different cooling temperatures in a liquid cooling garment (LCG), confirming the effectiveness of areas with high density tissue. The second study evaluated different configurations of hoods and neck scarves to maximize heat extraction from these key areas for heat release. The third study explored the possibility of regulating body heat by control of the water temperature circulating through selected body zones in the LCG, or blocking heat dissipation from particular body areas. The potential of heat insertion/removal from the head, hands, and feet to stabilize body comfort was evaluated in terms of the ability to advance this heat current “highway” from the core.

The correlations between the physical properties and autoignition parameters of several alternate fuels have been examined. The fuels are DF-2 and its blends with petroleum derived fuels, coal derived fuels, shale derived fuels, high aromatic naphtha sun-flower oils, methanol and ethanol. A total of eighteen existing correlations are discussed. An emphasis is made on the suitability of each of the correlations for the development of electronic controls for diesel engines when run on alternate fuels. A new correlation has been developed between the cetane number of the fuels and its kinematic viscosity and specific gravity.

Extended range electric vehicles (EREVs) are a potential solution for fossil fuel usage mitigation and on-road emissions reduction. The use of EREVs can be shown to yield significant fuel economy improvements when proper energy management strategies (EMSs) are employed. However, many in-use EREVs achieve only moderate fuel reduction compared to conventional vehicles due to the fact that their EMS is far from optimal. This paper focuses on in-use rule-based EMSs to improve the fuel efficiency of EREV last-mile delivery vehicles equipped with two-way Vehicle-to-Could (V2C) connectivity. The method uses previous vehicle data collected on actual delivery routes and machine learning methods to improve the fuel economy of future routes. The paper first introduces the main challenges of the project, such as inherent uncertainty in human driver behavior and in the roadway environment. Then, the framework of our practical physics-model guided data-driven approach is introduced.

A key challenge for the practical introduction of dual-fuel reactivity controlled compression ignition (RCCI) combustion modes in diesel engines is the requirement to store two fuels on-board. This work demonstrates that partially reforming diesel fuel into less reactive products is a promising method to allow RCCI to be implemented with a single stored fuel. Experiments were conducted using a thermally integrated reforming reactor in a reformed exhaust gas recirculation (R-EGR) configuration to achieve RCCI combustion using a light-duty diesel engine. The engine was operated at a low engine load and two reformed fuel percentages over ranges of exhaust gas recirculation (EGR) rate and main diesel fuel injection timing. Results show that RCCI-like emissions of NOx and soot were achieved load using the R-EGR configuration. It was also shown that complete fuel conversion in the reforming reactor is not necessary to achieve sufficiently low fuel reactivity for RCCI combustion.

The basis for performance and physical goals set for vehicular gas turbine air cleaners is followed by a discussion of laboratory and field test results obtained on air cleaners designed to meet the set goals. Test results indicate that: 1.) one level of protection, specifically one type of air cleaner, will probably not meet the needs of all types of gas turbines in various environments and applications; 2.) regenerative turbines may require a higher level of efficiency than non-regenerative turbines; 3.) a properly designed cyclone air cleaner will provide adequate protection for non-regenerative turbines and possibly some regenerative turbines; and 4.) properly designed extended area filters meet the air cleaner requirements of gas turbines in certain applications and environments. To obtain full benefit of an air cleaner design, the total induction system of the gas turbine must be planned early in vehicle design.

Exhaust particle number concentrations and size distributions were measured from the exhaust of a 1995 direct injection, Diesel engine. Number concentrations ranged from 1 to 7.5×107 particles/cm3. The number size distributions were bimodal and log-normal in form with a nuclei mode in the 7-15 nm diameter range and an accumulation mode in the 30-40 nm range. For nearly all operating conditions, more than 50% of the particle number, but less than 1% of the particle mass were found in the nuclei mode. Preliminary indications are that the nuclei mode particles are solid and formed from volatilization and subsequent nucleation of metallic ash from lubricating oil additives. Modern low emission engines produce low concentrations of soot agglomerates. The absence of these agglomerates to act as sites for adsorption or condensation of volatile materials makes nucleation and high number emissions more likely.

Particle concentrations and size distributions were measured in the exhaust of a turbocharged, aftercooled, direct-injection, Diesel engine equipped with a ceramic filter (trap). Measurements were performed both upstream and downstream of the filter using a two-stage, variable residence time, micro-dilution system, a condensation particle counter and a scanning mobility particle sizer set up to count and size particles in the 7-320 nm diameter range. Engine operating conditions of the ISO 11 Mode test were used. The engine out (upstream of filter) size distribution has a bimodal, log normal structure, consisting of a nuclei mode with a geometric number mean diameter, DGN, in the 10-30 nm range and an accumulation mode with DGN in the 50-80 nm range. The modal structure of the size distribution is less distinct downstream of the filter. Nearly all the particle number emissions come from the nuclei mode, are nanoparticles (Dp < 50nm), and are volatile.

The purpose of this study is to compare the dust loading behavior of ten filter media. The filters are used in engine air filtration, self-cleaning industrial air cleaners, building heating ventilation and cooling (HVAC), automotive cabin air filtration, air respirators, and general purpose air cleaning. Several types of filter media are tested. The filters include cellulose, synthetic (felt), glass, dual-layered glass/cellulose, mixed synthetic/glass, gradient packing glass, and electrically charged fibers. The initial pressure drops and fractional collection efficiencies as a function of particle size are reported. The filters were evaluated with two test dusts to investigate the size-dependent dust loading behavior. The two test dusts are SAE fine and submicron alumina powder (median diameter 0.25 μm). The results are analyzed and compared. It was found that the cellulose filters exhibited surface loading behavior and have the fastest growth of pressure drops.

This paper focuses on modeling of torque-biasing devices of a four-wheel-drive system used for improving vehicle stability and handling performance. The proposed driveline system is based on nominal front-wheel-drive operation with on-demand transfer of torque to the rear. The torque biasing components of the system are an electronically controlled center coupler and a rear electronically controlled limited slip differential. Kinematic modeling of the torque biasing devices is introduced including stage transitions during the locking stage and the unlocking/slipping stage. Analytical proofs of how torque biasing could be used to influence vehicle yaw dynamics are also included in the paper. A yaw control methodology utilizing the biasing devices is proposed. Finally, co-simulation results with Matlab®/Simulink® and CarSim® show the effectiveness of the torque biasing system in achieving yaw stability control.

Alcohols are examined as supplemental carbureted fuels for highspeed turbocharged diesels as typified by the White Motor/Waukesha F310 DBLT (6 cylinder, 310 cu. in.). Most of the work was with methanol; ethanol and isopropanol were compared at a few points. Fumigation (dual-fueling) with alcohol significantly reduced smoke and intake manifold temperature. These effects were largest at high load. Efficiency and HC emissions were essentially unchanged. Cylinder pressures and rise rates were examined for possible adverse effects on engine structure. The range of speed and load favorable to alcohol dual-fueling are such that, should alcohols become economically competitive as fuels, a practical duel-fuel system could be applied to existing diesel engines.

Introduction: There are contradictory opinions regarding the contribution of local hand thermal insulation to support local and total comfort during extravehicular activity (EVA). Instead of a local correction by means of thermal insulation on the periphery of the body to prevent heat dissipation, it may be optimal to prevent heat dissipation from the body core. To examine such a concept, the effects of different insulation levels on the left and right hands on the heat flux and temperature mosaic on the hands was measured. These variables were assessed in relation to the level of heat deficit forming in the core organs and tissues. Methods: Six subjects (4 males, 2 females) were donned in a liquid cooling/warming garment (LCWG) that totally covered the body surface except for the face. Participants wore the Phase VI space gloves including the entire micrometeoroid garment (TMG) on the left hand, and the glove without the TMG on the right hand.

The impact of compression ratio on engine efficiency is well known. A plethora of mechanical concepts have been proposed for altering engine compression ratio in real time. Some of these, like free-piston configurations or complex crank-slider mechanisms have the added ability to alter piston trajectory along with compression ratio. This secondary modality raises the question: Is there a more optimal piston position versus crank-angle profile for spark-ignition (SI) engines than the near-sinusoidal motion produced by a traditional four-bar crank-slider mechanism? Very little published literature directly addresses this question. This work presents the results of a quasi-dimensional SI engine model using piston trajectory as an input. Specific trajectory traits including increased dwell at top dead center and asymmetric compression and expansion strokes were swept. The trajectory also was optimized using a single objective genetic algorithm with 60 individuals and 40 generations.

Diesel particulate filter (DPF) technology has proven performance and reliability. However, the addition of a DPF adds significant cost and packaging constraints leading some manufacturers to design engines that reduce particulate matter in-cylinder. Such engines utilize high fuel injection pressure, moderate exhaust gas recirculation and modified injection timing to mitigate soot formation. This study examines such an engine designed to meet US EPA Interim Tier 4 standards for off-highway applications without a DPF. The engine was operated at four steady state modes and aerosol measurements were made using a two-stage, ejector dilution system with a scanning mobility particle sizer (SMPS) equipped with a catalytic stripper (CS) to differentiate semi-volatile versus solid components in the exhaust. Gaseous emissions were measured using an FTIR analyzer and particulate matter mass emissions were estimated using SMPS data and an assumed particle density function.

As part of an ongoing program to control the emissions of diesel-powered equipment used in underground mines, the U. S. Bureau of Mines evaluated exhaust emissions from a compression ignition engine using oxygenated diesel fuels and a diesel oxidation catalyst (DOC). The fuels include neat (100%) soy methyl ester (SME), and a blend of 30% SME (by volume) with 70% petroleum diesel fuel. A Caterpillar 3304 PCNA engine was tested for approximately 50 hours on each fuel. Compared with commercial low-sulfur diesel fuel (D2), neat SME increased volatile organic diesel particulate matter (DPM) but greatly decreased non-volatile DPM, for a net decrease in total DPM. The DOC further reduced volatile and total DPM NOx emissions were slightly reduced for the case of neat SME, but otherwise were not significantly affected. Peak brake power decreased 9% and brake specific fuel consumption increased 13 to 14% for the neat methyl soyate because of its lower energy content compared with D2.

A 1.9 liter Volkswagen TDI engine has been modified to accomodate the addition of hydrogen into the intake manifold via timed port fuel injection. Engine out particulate matter and the emissions of oxides of nitrogen were investigated. Two fuels,low sulfur diesel fuel (BP50) and soy methyl ester (SME) biodiesel (B99), were tested with supplemental hydrogen fueling. Three test conditions were selected to represent a range of engine operating modes. The tests were executed at 20, 40, and 60 % rated load with a constant engine speed o 1700 RPM. At each test condition the percentage of power from hydrogen energy was varied from 0 to 40 %. This corresponds to hydrogen flow rates ranging from 7 to 85 liters per minute. Particulate matter (PM) emissions were measured using a scaning mobility particle sizer (SMPS) and a two stage micro dilution system. Oxides of nitrogen were also monitored.

In-cylinder reforming of injected fuel during an auxiliary negative valve overlap (NVO) period can be used to optimize main-cycle auto-ignition phasing for low-load Low-Temperature Gasoline Combustion (LTGC), where highly dilute mixtures can lead to poor combustion stability. When mixed with fresh intake charge and fuel, these reformate streams can alter overall charge reactivity characteristics. The central issue remains large parasitic heat losses from the retention and compression of hot exhaust gases along with modest pumping losses that result from mixing hot NVO-period gases with the cooler intake charge. Accurate determination of total cycle energy utilization is complicated by the fact that NVO-period retained fuel energy is consumed during the subsequent main combustion period. For the present study, a full-cycle energy analysis was performed for a single-cylinder research engine undergoing LTGC with varying NVO auxiliary fueling rates and injection timing.

Previously, the authors have proposed a novel strategy called trajectory based combustion control for the free piston engine (FPE) where the shape of the piston trajectory between top and bottom dead centers is used as a control input to modulate the chemical kinetics of the fuel-air mixture inside the combustion chamber. It has been shown that in case of a hydraulic free piston engine (HFPE), using active motion control, the piston inside the combustion chamber can be forced to track any desired trajectory, despite the absence of a crankshaft, providing reliable starting and stable operation. This allows the use of optimized piston trajectory for every operating point which minimizes fuel consumption and emissions. In this work, this concept is extended to an electrical free piston engine (EFPE) as a modular power source.