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This paper presents 3D finite element analysis performed for a composite cylindrical tank made of 6061-aluminum liner overwrapped with carbon fibers subjected to a burst internal pressure of 1610 bars. As the service pressure expected in these tanks is 700 bars, a factor of safety of 2.3 is kept the same for all designs. The optimal design configuration of such high pressure storage tanks includes an inner liner used as a gas permeation barrier, geometrically optimized domes, inlet/outlet valves with minimum stress concentrations, and directionally tailored exterior reinforcement for high strength and stiffness. Filament winding of pressure vessels made of fiber composite materials is the most efficient manufacturing method for such high pressure hydrogen storage tanks. The complexity of the filament winding process in the dome region is characterized by continually changing the fiber orientation angle and the local thickness of the wall.

The need for a cleaner and less expensive alternative energy source to conventional petroleum fuels for powering the transportation sector has gained increasing attention during the past decade. Special attention has been directed towards natural gas (NG) which has proven to be a viable option due to its clean-burning properties, reduced cost and abundant availability, and therefore, lead to a steady increase in the worldwide vehicle population operated with NG. The heavy-duty vehicle sector has seen the introduction of natural gas first in larger, locally operated fleets, such as transit buses or refuse-haulers. However, with increasing expansion of the NG distribution network more drayage and long-haul fleets are beginning to adopt natural gas as a fuel.

Currently, the chassis assembly contributes about 73 percent of the overall weight of a 14.63 m long haul trailer. This paper presents alternative design concepts for the structural floor of a van trailer utilizing sandwich panels with various material and geometric characteristics of the core layer in order to reduce its weight significantly below that of the current design configuration. The main objective of the new designs is to achieve optimal tradeoffs between the overall structural weight and the flexural stiffness of the floor. Various preliminary design concepts of the core designs were compared on the basis of a single section of the core structure. Six different designs were analyzed by weight, maximum displacement and maximum stress under bending and torsion loads. Each concept was kept uniform by length, thickness, loading and boundary conditions. Each design concept was examined through testing of scaled model for floor assemblies.

Recent advances in Metal Matrix Composites have made them ready for transition to large-volume production and commercialization. Such new materials seem to allow the fabrication of higher quality parts at less than 50 percent of the weight as compared to steel. The increasing requirements of weight savings and extended durability motivated the potential application of MMC technology into the heavy vehicle market. However, significant technical barriers such as joining are likely to hinder the broad applications of MMC materials in heavy vehicles. The focus of this paper is to examine the feasibility of manufacturing and the behavior of bolted joint connections made from aluminum matrix reinforced with Silicon Carbide (SiC) particles. Two reinforcement ratios: 20% and 45% were considered in this study. The first part of the paper concentrates on experimental evaluation of bolted MMC joints.

Incidents in which a piece of construction equipment backed into a worker resulted in an average of 17 deaths per year at road construction sites and 15 deaths per year at building construction sites from 1997 through 2001. This trend continues and researchers at the National Institute for Occupational Safety and Health are evaluating methods to decrease these incidents. A new technology based on the detection of electronic identification tags worn by workers has been developed and evaluated at a road construction site. The tag-based proximity warning system consists of a magnetic field generator and communications system that mounts on the back of a piece of construction equipment such as a dump truck, road grader, or loader. Workers at a construction site wear a small tag that detects the magnetic marker field.

Carbon Monoxide (CO) has become a pressing issue for the recreational marine industry. An increasing number of boating incidents have been linked to CO poisoning caused by emissions from gasoline-powered marine engines. Measurements by the National Institute for Occupational Safety and Health (NIOSH) and the U.S. Coast Guard have confirmed potentially hazardous CO concentrations near many of these engines. The measurements have also shown much lower CO concentrations for Evinrude® two-stroke direct-injected engines. This paper reviews national and international CO emission regulations for marine engines and discusses CO formation and reduction mechanisms. The differences between homogeneous- and stratified-charge combustion systems on CO formation, resulting from design and calibration criteria, are analyzed.

Further growth of diesel engines in the light-duty and heavy-duty vehicular market is closely linked to the potential health risks of diesel exhaust. The California Air Resources Board and the Office of Environmental Health Hazard Assessment have identified diesel exhaust as a toxic air contaminant. The International Agency for Research on Cancer concluded that diesel particulate is a probable human carcinogen [1]. Cleaner burning liquid fuels, such as those derived from natural gas via the Fischer-Tropsch (FT) process, offer a potentially economically viable alternative to standard diesel fuel while providing reduced particulate emissions. Further understanding of FT operation may be realized by investigating the differences in toxicity and potential health effects between particulate matter(PM) derived from FT fuel and that derived from standard Federal diesel No. 2 (DF).

The emissions reduction of Fischer-Tropsch (FT) diesel fuel has been demonstrated in several recent publications in both laboratory engine testing and in-use vehicle testing. Reduced emission levels have been attributed to several chemical and physical characteristics of the FT fuels including reduced density, ultra-low sulfur levels, low aromatic content and high cetane rating. Some of the effects of these attributes on the combustion characteristics in diesel engines have only recently been documented. In this study, a Ricardo Proteous, single-cylinder, 4-stroke DI engine is instrumented for in-cylinder pressure measurements. The engine was run at several steady engine states at multiple timing conditions using both federal low sulfur and natural gas derived FT fuels. The emissions and performance data for each fuel at each steady state operating conditions were compared.

Specific aspects of a study aimed at developing a microwave assisted regeneration system for diesel particulate traps are discussed. Results from thermal and microwave characteristic studies carried out in the initial phase of the study are reported. The critical parameters that need to be optimized, for achieving controlled regeneration, are microwave preheating time period, regenerative air supply, regenerative air temperature, and soot deposition. Using a 1000 W magnetron, power measurements were made to select the best waveguide configuration for optimized transmission. A six cylinder naturally aspirated, indirect injection diesel engine was retrofitted with a customized exhaust system that included a Corning EX80 (5.66″ × 6.00″) type ceramic particulate trap. An automated exhaust bypass system enabled trap loading and subsequent regeneration with a customized microwave regeneration system. The paper discusses the salient details of both on-line and off-line regeneration setups.

Diesel soot interacts with the engine oil and leads to wear of engine parts. Engine oil additives play a crucial role in preventing wear by forming the anti-wear film between the wearing surfaces. The current study was aimed at investigating the interactions between engine soot and oil properties in order to develop high performance oils for diesel engines equipped with exhaust gas re-circulation (EGR). The effect of soot contaminated oil on wear of engine components was examined using a statistically designed experiment. To quantitatively analyze and simulate the extent of wear a three-body wear machine was designed and developed. The qualitative wear analysis was performed by examining the wear scars on an AISI 52100 stainless steel ball worn in the presence of oil test samples on a ball-on-flat disc setup. The three oil properties studied were base stock, dispersant level and zinc dithiophosphate level.

Natural Gas engines are viewed as an alternative to diesel power in the quest to reduce heavy duty vehicle emissions in polluted urban areas. In particular, it is acknowledged that natural gas has the potential to reduce the inventory of particulate matter, and this has encouraged the use of natural gas engines in transit bus applications. Extensive data on natural gas and diesel bus emissions have been gathered using two Transportable Heavy Duty Vehicle Emissions Testing Laboratories, that employ chassis dynamometers to simulate bus inertia and road load. Most of the natural gas buses tested prior to 1997 were powered by Cummins L-10 engines, which were lean-burn and employed a mechanical mixer for fuel introduction. The Central Business District (CBD) cycle was used as the test schedule.

This paper presents results from a study on speciation of the emission profiles and on the ozone forming potential of heavy-duty diesel exhaust under steady state engine operation. Very limited attempts have been made at determining the ozone forming potential of heavy duty diesel exhaust emissions. In this study a proportional sample of the dilute exhaust was drawn from a CFV-CVS system using a temperature controlled sampling line. The particulate matter was collected on a 70 mm Teflon coated glass fiber filter (TX40HI20WW), the semi-volatiles on XAD-2 copolymer resin and volatiles in Tedlar bags. The samples were analyzed by gas chromatography after conditioning and chemical extractions. The initial phase of the study was directed towards developing techniques and establishing protocols to determine the ozone forming potential of heavy-duty diesel exhaust. A pre-chamber naturally aspirated engine was tested on steady-state modes 1, 3, 5, 7 and 8 of the ISO 8 mode cycle.

A novel engine concept, currently under study, addresses many of the problems commonly associated with conventional internal combustion engines. In its simplest form the novel engine consists of a single crankshaft operating both a piston compressor and a piston expander which are connected by a continuous flame combustion chamber. One might regard this as a Brayton piston engine which is similar to a previous engine investigated by Warren. Also, due to the use of piston cylinders as the compression and expansion devices, this engine varies little mechanically from current engine technology thus allowing for easy implementation. The main improvement from conventional engine design is that the expansion cylinder can have a larger displacement than that of the compression cylinder. This allows more power to be extracted by lowering the loss due to blowdown and this will increase the thermal efficiency.

With the implementation of a closed loop fuel control system, operation of lean-burn natural gas engines can be optimized in terms of reducing emissions while maximizing efficiency. Such a system would compensate for variations in fuel composition, but also would correct for variations in volumetric efficiency due to immediate engine history and long-term engine component wear. Present day engine controllers perform well when they are operated with the same gas composition for which they were calibrated, but because fuel composition varies geographically as well as seasonally, some method of compensation is required. A closed loop control system on a medium-duty lean-burn engine will enhance performance by maintaining the desired air-fuel ratio to eliminate any unwanted rich or lean excursions (relative to the desired air-fuel ratio) that produce excess engine-out emissions. Such a system can also guard against internal engine damage due to overheating and/or engine knock.

In this paper, a new method for the hydro-dynamic analysis of a sliding cylinder in a fully lubricated parallel track is presented. The method is an extension of Booker's “Mobility Method” (developed for cylindrical journal bearings) to the case of sliding cylinders, in which the clearance between the track and the cylinder, the viscosity of the lubricant, the radius and length of the pin, the sliding velocity and the applied transverse load determine the hydrodynamic behavior of the cylinder. In the Rand Cam™ Engine [1]*, the axicycloidal motion of vanes is driven by a rotor and a cylindrical cam, and one of the alternative designs to provide this function is based on a cylindrical pin sliding within a track which follows the profile of the motion of the main cams of the engine. This function is very important for the engine, since it separates the load bearing function from the sealing function left to the apex-like seals.

Techniques have been developed to sample and speciate dilute heavy duty diesel exhaust to determine the specific reactivities and the ozone forming potential. While the Auto/Oil Air Quality Improvement Research Program (AQIRP) has conducted a comprehensive investigation to develop data on potential improvements in vehicle emissions and air quality from reformulated gasoline and various other alternative fuels. However, the development of sampling protocols and speciation of heavy duty diesel exhaust is still in its infancy [1, 2, 3, 4, 5 and 6]. This paper focuses on the first phase of the heavy duty diesel speciation program, that involves the development of a unique set of sampling protocols for the gas phase, semi-volatile and particulate matter from the exhaust of engines operating on different types of diesel fuel. Effects of sampling trains, sampling temperatures, semi-volatile adsorbents and driving cycles are being investigated.

A bi-fuel engine with the ability to run optimally on both compressed natural gas (CNG) and gasoline is being developed. Such bi-fuel automotive engines are necessary to bridge the gap between gasoline and natural gas as an alternative fuel while natural gas fueling stations are not yet common enough to make a dedicated natural gas vehicle practical. As an example of modern progressive engine design, a Saturn 1.9 liter 4-cylinder dual overhead cam (DOHC) engine has been selected as a base powerplant for this development. Many previous natural gas conversions have made compromises in engine control strategies, including mapped open-loop methods, or resorting to translating the signals to or from the original controller. The engine control system described here, however, employs adaptive closed-loop control, optimizing fuel delivery and spark timing for both fuels.

The Rand-Cam engine is a positive displacement machine, operating on a four stroke cycle, which consists of a rotor with multiple axial vanes forming combustion chambers as the rotor and vanes rotate in a cam shaped housing. The cam housing, consisting of two “half-housings” or stators, contains a toroidal trough of varying depth machined into each stator. The two stators are phased so that the shallowest point on one trough corresponds to the deepest on the other. A set of six vanes, able to move axially through machined holes in the rotor, traverses the troughs creating six captured zones per side. These zones vary in volume with rotor rotation. Since each trough has two deep sections and two shallow sections with ramps in between, full four stroke operation is obtained between each pair of vanes in each trough, corresponding to twelve power “strokes” per revolution.

The Rand Cam engine is a novel design which avoids the use of pistons in favor of a cavity of varying size and shape. A set of vanes protrudes from a rotor into a circular trough in a stator. The vanes seal to the walls and base of the trough, which is of varying depth, and progress around the trough with rotation of the rotor. These vanes therefore pass through the rotor and are constrained to move parallel to the rotational axis. Intake and exhaust processes occur through ports in the stator wall which are revealed by the passing vanes. Advantages of the basic design include an absence of valves, reduction in reciprocating masses, presence of an integral flywheel in the rotor and strong fluid movement akin a swirl induced by the relative velocity between the rotor and stator.

A set of experiments were conducted to evaluate the performance differences between a Low Heat Rejection Engine (LHRE) which is ceramic-insulated and a conventional baseline metal diesel engine which is water-cooled. Both engines were single cylinder, direct injection, and turbocharged. The objective of the study was to investigate the rate of heat release of these engines so that performance improvement procedures could be obtained. In this paper, the difference of the ignition delay between the two engines was determined. Two methods for improving the combustion process of the LHRE were studied: use of mixture fuels and increase the fuel injection rate. Both methods proved effective and reduced the fuel consumption rate of the LHRE.