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Honda has succeeded in developing the new fuel cell (FC) vehicle designed into a dynamic, full-cabin sedan, the FCX Clarity, originating from the new V Flow FC platform. The key technology is V Flow FC Stack, featuring V Flow cell structure in which the fuel gases run from top to bottom vertically through the wave flow-channels. According to this unique structure, the fuel cell stack sits longitudinally along the center tunnel, and a Vertebral layout has emerged. The Vertebral layout results in Volume efficient package and low-floor platform. The V Flow FC stack has achieved a high output of 100kW and improved the output density with 50% by volume and 67% by mass, compared to the previous 2005 model. The V Flow cell structure utilizes gravity for water drainage and reduces the channel depth creating thinner cells. The wave-shaped vertical gas flow channel provides horizontal and more efficient coolant flow distribution allowing the reduction of the number of cooling layer.

This paper reports an active heat sink (AHS) that allows high-density electronic components to operate at a stable temperature over a broad range of ambient conditions. AHS receives heat at high flux and transfers it at reduced flux to environment, coolant fluid (e.g., air or engine coolant), or structures. Temperature of the heat load can be controlled electronically. Target applications for AHS include thermal management of the new class of high-power electronics being developed for electric hybrid vehicles. AHS also enables precise control over junction temperature (and, thus, light color) of high-power light-emitting diodes (LED) used for solid-state headlights and allows for compact air-cooled heat sinks. Depending on the configuration, AHS thermal resistance can be as low as 0.1 degC/W. AHS physics, engineering design, and performance simulations are presented.

The acoustic impedance of a circular, confined, side branch orifice subjected to grazing flow is studied. Two geometries are tested. In both geometries, the side branch dimension is of the same order as that of the main duct. The system is viewed as an acoustic three-port, whose passive properties are described by a system matrix. The impedance is studied with the acoustic field incident at different ports, which is shown to influence the results significantly. When excited from the leading edge or from the side branch, an interaction of the hydrodynamic and acoustic fields is triggered, while excitation from the trailing edge does not trigger such an interaction. For both the resistance and the reactance (here expressed as an end correction) the results vary in the three possible excitation cases. In the quasi-stationary limit the resistance is given by a loss coefficient times the Mach number, and the end correction collapses to a single value.

The Space Suit Water Membrane Evaporator (SWME) is a baseline heat rejection technology that was selected to develop the Constellation Program lunar suit. The Hollow Fiber (HoFi) SWME is being considered for service in the Constellation Space Suit Element Portable Life Support Subsystem to provide cooling to the thermal loop via water evaporation to the vacuum of space. Previous work [1] described the test methodology and planning that are entailed in comparing the test performance of three commercially available HoFi materials as alternatives to the sheet membrane prototype for SWME: (1) porous hydrophobic polypropylene, (2) porous hydrophobic polysulfone, and (3) ion exchange through nonporous hydrophilic-modified Nafion®.

The Mars Science Laboratory (MSL) mission to land a large rover on Mars is being prepared for Launch in 2011. A Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) on the rover provides an electrical power of 110 W for use in the rover and the science payload. Unlike the solar arrays, MMRTG provides a constant electrical power during both day and night for all seasons (year around) and latitudes. The MMRTG dissipates about 2000 W of waste heat to produce the desired electrical power. One of the challenges for MSL Rover is the thermal management of the large amount of MMRTG waste heat. During operations on the surface of Mars this heat can be harnessed to maintain the rover and the science payload within their allowable limits during nights and winters without the use of electrical survival heaters. A mechanically pumped fluid loop heat rejection and recovery system (HRS) is used to pick up some of this waste heat and supply it to the rover and payload.

A heavy truck wind tunnel test program is currently underway at the Langley Full Scale Tunnel (LFST). Seven passive drag reducing device configurations have been evaluated on a heavy truck model with the objective of understanding the practical limits to drag reduction achievable on a modern tractor trailer through add-on devices. The configurations tested include side skirts of varying length, a full gap seal, and tapered rear panels. All configurations were evaluated over a nominal 15 degree yaw sweep to establish wind averaged drag coefficients over a broad speed range using SAE J1252. The tests were conducted by first quantifying the benefit of each individual treatment and finally looking at the combined benefit of an ideal fully treated vehicle. Results show a maximum achievable gain in wind averaged drag coefficient (65 mph) of about 31 percent for the modern conventional-cab tractor-trailer.

The commercial turbofan trend of increasing bypass ratio and decreasing fan pressure ratio has seen its latest market entry in Pratt & Whitney's PurePower™ product line, which will power regional aircraft for the Bombardier and Mitsubishi corporations, starting in 2013. The high-bypass-ratio, low-fan-pressure-ratio trend, which is aimed at diminishing noise while increasing propulsive efficiency, combines with contemporary business factors including the escalating cost of testing and limited availability of simulated altitude test sites to pose formidable challenges for engine certification and performance validation. Most fundamentally, high bypass ratio and low fan pressure ratio drive increased gross-to-net thrust ratio and decreased fan temperature rise, magnifying by a factor of two or more the sensitivity of in-flight thrust and low spool efficiency to errors of measurement and assumption, i.e., physical modeling.

The volatile organic compounds (VOC) from diesel engines, including formaldehyde and benzene, are concerned and remain as unregulated harmful substances. The substances are positively correlated with THC emissions, but the VOC and aldehyde compounds at light load or idling conditions are more significant than THC. When coolant temperatures are low at light loads, there are notable increases in formaldehyde and acetaldehyde, and with lower coolant temperatures the increase in aldehydes is more significant than the increase in THC. When using ultra high EGR so that the intake oxygen content decreases below 10%, formaldehyde, acetaldehyde, benzene, and 1,3-butadiene increase significantly while smokeless and ultra low Nox combustion is possible.

Scuffing is a common source of failure for many mechanical components in automobiles. 8625 alloy steel is commonly used in camshafts, gears, piston pins, shafts, and splines. The purpose of the research is to study the scuffing resistance of non-treated, carburized, nitrocarburized, and carbonitrided 8625 alloy steels. The scuffing resistance of the 8625 alloy steels was determined through pin-on-disk tests. The hardness and microstructure of the disks were analyzed using electron microscopy to determine wear mechanisms for each surface treated steel. The wear mechanisms were then related to the scuff resistance of the various materials.

In cold climatic regions (25°C below zero) thermal comfort inside vehicle cabin plays a vital role for safety of driver and crew members. This comfortable and safe environment can be achieved either by utilizing available heat of engine coolant in conjunction with optimized in cab air circulation or by deploying more costly options such as auxiliary heaters, e.g., Fuel Fired, Positive Temperature Coefficient heaters. The typical vehicle cabin heating system effectiveness depends on optimized warm/hot air discharge through instrument panel and foot vents, air directivity to occupant's chest and foot zones and overall air flow distribution inside the vehicle cabin. On engine side it depends on engine coolant warm up and flow rate, coolant pipe routing, coolant leakage through engine thermostat and heater core construction and capacity.

Al383/SiO₂ metal matrix composites (MMC) were designed to increase the wear properties of the Al alloy. However, the soft Al matrix was subject to large plastic deformation under high normal load during lubricated sliding wear tests, causing detachment of the reinforced particles. To further increase the wear resistance of the MMC, in this research, Plasma Electrolytic Oxidation (PEO) process was used to form oxide coatings on the MMC. The hard and wear-resistant oxide coatings protected the metal matrix during the wear tests, reducing the wear rate of MMC. The effect of both oxide coating thickness and volume content of SiO₂ particles on the wear behavior of MMC was investigated. It was found that with a proper combination of the volume content of SiO₂ and coating thickness, the MMC exhibited high wear resistance and low friction coefficient.

During the automotive brake system design and development process, a large number of performance characteristics must be comprehended, assessed, and balanced against each other and, at times, competing performance objectives for the vehicle under development. One area in brake development that is critical to customer acceptance due to its impact on a vehicle's perceived quality is brake pedal feel. While a number of papers have focused on the specification, quantification and modeling of brake pedal feel and the various subsystem characteristics that affect it, few papers have focused specifically on brake corner hoses and their effect on pedal feel, in particular, during race-track conditions. Specifically, the effects of brake hose fluid consumption pedal travel and brake system response is not well comprehended during the brake development process.

This paper presents a new approach to analyzing and developing low-drag cooling systems. A relation is derived which describes cooling drag by a number of contributions. Interference drag clearly can be identified as one of them. Cooling system parameters can be assigned to different terms of the relation, so that differences due to parameter variations of the individual drag contributions can be estimated. In order to predict the interference-drag dependency on the outlet location and the local outlet mass flow, an extensive study on a standard BMW sedan has been carried out, both experimentally and by CFD. The results show the importance of providing consistent outflow conditions which take into account the outlet location and flow direction, in order to minimize cooling drag.

A new liquid surface conditioner has been developed to improve phosphate coating quality and enable a low-temperature phosphating system designed to reduce CO₂ emissions during the pretreatment processes of automobile production. Phosphate film is formed by a phosphating treatment that provides corrosion resistance for the steel plates that make up auto bodies. In the vehicle body, pocket-shaped structures such as side sills and wheel arches are likely to collect muddy water and form rust. Regarding anticorrosion quality assurance, particular attention must be paid to these pocket structures, in which phosphating solution flows slowly, and a lower solution-volume-to-surface-area ratio contributes less to the phosphating reaction. For this reason, with the conventional liquid surface conditioner, a low-temperature phosphating system cannot coat substrate surfaces sufficiently, which would result in lower corrosion resistance.

Structural adhesive joints are expected to retain integrity in their entire service-life that normally involves cyclic loading concurrent with environmental exposure. Under such a severe working condition, effective determination of fatigue life at different temperatures is crucial for reliable joint design. The main goal of this work was thus defined as evaluation of fatigue performance of adhesive joints at their extreme working temperatures in order to be compared with their fracture properties under static loading. A series of standard double-cantilever-beam (DCB) specimens have been bonded by three structural 3M epoxy adhesives selected from different applications. The specimens were tested under monotonic and cyclic opening loads (mode-I) in order to evaluate the quasi-static and fatigue performances of selected adhesives at room temperature, 80°C and -40°C.

Friction Stir Spot Welding (FSSW) is a relatively new solid state joining technology that has the potential to be a replacement for single point joining processes like Resistance Spot Welding and rivet technology in certain applications. Since the material flow around the pin plays an important role in determining the quality of the weld, understanding how the material moves is important to optimize process parameters and to validate the results of numerical simulations of the process. In this paper, an experimental study aimed at visualizing the material flow during the plunge phase of refill FSSW of an aluminum alloy is presented. Different marker materials were placed at a certain depth from the plate surface and metallographic samples in three mutually perpendicular directions were prepared and examined to identify the final location of the marker material after the plunge of the pin.

The technology concerning thermo and fluid dynamics is one of the important fields which have made great progress along with rapid advance in computational resources. Especially, the CFD technology has been proved as successful contribution to the development of the engine cooling system. Therefore, this technology is widely used at early phase of the vehicle development. However, a serious problem has been remained that it does not always give practical precision. Particularly, the cooling fan is one of the primary components in the cooling system to determine the performance, while practical calculation method without depending on large resources has not established.

Automobile engine compartments are exposed to much wider temperature and moisture-level changes than passenger compartments. Therefore, for electrical components housed in the engine compartment, protection of printed circuit boards is extremely important in order to prevent open or short circuits caused by electrochemical reactions. It is well known that silicon oxide accumulates on electromagnetic relay contacts, and may cause degraded circuits once volatile low-mass cyclic polydimetylsiloxane from a commonly used silicone gel waterproofing material reacts in a direct-current arc that occurs when the contacts open and close. Material selection for relay modules is critical in order to avoid this phenomenon. We used a gel material jointly developed with a supplier, and evaluated its reliability compared to silicone in terms of relay operation. This material is a polymer resin that consists of poly(n-butyl acrylate) as the main component, linked through silicon.

Various payloads, such as electronic systems, have become an integral part of modern military ground vehicles. These payloads often feature high thermal density that need to be effectively managed, especially under demanding operating conditions, to maintain system reliability. This paper describes the modeling and analysis of a nanofluid augmented coolant rail combined with thermoelectric devices to address the cooling challenges posed by these payloads. A sensitivity analysis has been performed to investigate the nanoparticle enhancement model. Numerical results obtained show that the convective heat transfer coefficient can be enhanced by up to 16% with the augmentation of nanoparticles into the base fluid. The results also show that the peak computer temperature is rather insensitive to the complexity of the model used and that the proposed system provides cooling performance which would not be possible with traditional air-cooled heat sinks.

Cell balancing is a key function of battery management system (BMS) that is implemented to maximize the battery's available capacity and service life. The increasing demand of larger and better performance pack has raised the need to investigate the various cell balancing techniques so that the energy of the battery can be fully realized. In this work we develop a phenomenological model in order to quantify the benefits of passive balancing and active balancing. The electrical response of a model pack consisting of serially connected lithium ion cells is simulated with Matlab. The effects of the variance of cell capacity, internal resistance, self-discharge rates, pack configuration and size are studied. The possible optimization rooms for implementing passive and active balancing are suggested.