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A state of the art proprietary method for aluminum-to-aluminum joining in the automotive industry is Resistance Spot Welding. However, with spot welding (1) structural performance of the joint may be degraded through heat-affected zones created by the high temperature thermal joining process, (2) achieving the double-sided access necessary for the spot welding electrodes may limit design flexibility, and (3) variability with welds leads to production inconsistencies. Self-piercing rivets have been used before; however they require different rivet/die combinations depending on the material being joined, which adds to process complexity. In recent years the introductions of screw products that combine the technologies of friction drilling and thread forming have entered the market. These types of screw products do not have these access limitations as through-part connections are formed by one-sided access using a thermo-mechanical flow screwdriving process with minimal heat.

This manuscript provides a review of different types and categorization of the chassis dynamometer systems. The review classifies the chassis dynamometers based on the configuration, type of rollers and the application type. Additionally the manuscript discusses several application examples of the chassis dynamometer including: performance and endurance mileage accumulation tests, fuel efficiency and exhaust emissions, noise, vibration and harshness testing (NVH). Different types of the vehicle attachment system in the dynamometer cell and its influences on the driving force characteristics and the vehicle acoustic signature is also discussed. The text also highlights the impact of the use of the chassis dynamometer as a development platform and its impact on the development process. Examples of using chassis dynamometer as a development platform using Vehicle Hardware In-the-Loop (VHiL) approach including drivability assessment and transmission calibrations are presented.

NASA's proposed lunar lander, Altair, will be exposed to vastly different external temperatures following launch till its final destination on the moon. In addition, the heat rejection is lowest at the lowest environmental temperatures (0.5 kW @ 4K) and highest at the highest environmental temperature (4.5 kW @ 215K). This places a severe demand on the radiator design to handle these extreme turn-down requirements. A radiator with digital turn-down capability is currently under study at JPL as a robust means to meet the heat rejection demands and provide freeze protection while minimizing mass and power consumption. Turndown is achieved by independent control of flow branches with isolating latch valves and a gear pump to evacuate the isolated branches. A bench-top test was conducted to characterize the digital radiator concept. Testing focused on the demonstration of proper valve sequencing to achieve turn-down and recharge of flow legs.

The use of Low Pressure - Exhaust Gas Recirculation (EGR) is intended to allow displacement reduction in turbocharged gasoline engines and improve fuel economy. Low Pressure EGR designs have an advantage over High Pressure configurations since they interfere less with turbocharger efficiency and improve the uniformity of air-EGR mixing in the engine. In this research, Low Pressure (LP) cooled EGR is evaluated on a turbocharged direct injection gasoline engine with variable valve timing using both simulation and experimental results. First, a model-based calibration study is conducted using simulation tools to identify fuel efficiency gains of LP EGR over the base calibration. The main sources of the efficiency improvement are then quantified individually, focusing on part-load de-throttling of the engine, heat loss reduction, knock mitigation as well as decreased high-load fuel enrichment through exhaust temperature reduction.

The pursuit of greater fuel economy in internal combustion engines requires the optimization of all subsystems including thermal management. The reduction of cooling power required by the electromechanical coolant pump, radiator fan(s), and thermal valve demands real time control strategies. To maintain the engine temperature within prescribed limits for different operating conditions, the continual estimation of the heat removal needs and the synergistic operation of the cooling system components must be accomplished. The reductions in thermal management power consumption can be achieved by avoiding unnecessary overcooling efforts which are often accommodated by extreme thermostat valve positions. In this paper, an optimal nonlinear controller for a military M-ATV engine cooling system will be presented. The prescribed engine coolant temperature will be tracked while minimizing the pump, fan(s), and valve power usage.

Hybrid vehicle embedded systems and payloads require progressively more accurate and versatile thermal control mechanisms and strategies capable of withstanding harsh environments and increasing power density. The division of the cargo and passenger compartments into convective thermal zones which are independently managed can lead to a manageable temperature control problem. This study investigates the performance of a Peltier-effect thermoelectric zone cooling system to regulate the temperature of target objects (e.g., electronic controllers, auxiliary computer equipment, etc) within ground vehicles. Multiple thermoelectric cooling modules (TEC) are integrated with convective cooling fans to provide chilled air for convective heat transfer from a robust, compact, and solid state device. A series of control strategies have been designed and evaluated to track a prescribed time-varying temperature profile while minimizing power consumption.

The automotive cooling system configuration has remained fixed for many decades with a large radiator plus fan, coolant pump, and bypass valve. To reduce cooling system power consumption, the introduction of multiple computer-controlled heat exchangers may offer some benefits. A paradigm shift from a single large radiator, sized for maximum load, to n-small radiators with individual flow control valves should allow fine tuning of the heat rejection needs to minimize power. In this project, a series of experimental scenarios featuring two identical parallel radiators have been studied for low thermal load engine cooling (e.g., idling) in ground transportation applications. For high thermal load scenarios using two radiators, the fans required between 1120 - 3600 W to maintain the system about the coolant reference temperature of 85oC.

Providing water necessary to maintain life support has been accomplished in spacecraft vehicles for over forty years. This paper will investigate how previous U.S. space vehicles provided potable water. The water source for the spacecraft, biocide used to preserve the water on-orbit, water stowage methodology, materials, pumping mechanisms, on-orbit water requirements, and water temperature requirements will be discussed. Where available, the hardware used to provide the water and the general function of that hardware will also be detailed. The Crew Exploration Vehicle (CEV or Orion) water systems will be generically discussed to provide a glimpse of how similar they are to water systems in previous vehicles. Conclusions, questions, and recommendations on strategies that could be applied to CEV based on previous spacecraft water system lessons learned will be made.

The emphasis on vehicle fuel economy and tailpipe emissions, coupled with a trend toward greater system functionally, has prompted automotive engineers to develop on-board control systems with increased requirements and complexity. Mainstream engine controllers regulate fuel, spark, and other subsystems using custom solutions that incorporate off-the-shelf hardware components. Although the digital processor core and the peripheral electronics may be similar, these controllers are targeted to fixed engine architectures which limit their flexibility across vehicle platforms. Moreover, additional software needs are emerging as electronics continue to permeate the ground transportation sector. Thus, automotive controllers will be required to assume increased responsibility while effectively communicating with distributed hardware modules.

ILC Dover Inc. was awarded a three-year NRA grant for the development of innovative spacesuit pressure garment technology that will enable safer, more reliable, and effective human exploration of the space frontier. The research focused on the development of a high performance mobility/sizing actuation system for a spacesuit soft upper torso (SUT) pressure garment. This technology has application in two areas (1) repositioning the scye bearings to improve specific joint motion i.e. hammering (Figure 1), hand over hand translation (Figure 2), etc., and (2) as a suit sizing mechanism to allow easier suit entry and more accurate suit fit with fewer torso sizes than the existing EMU. This research was divided into three phases. In phases 1 and 2 SUT actuation technologies were developed and evaluated.

When a permanent human outpost is established on the Moon, various methods may be used to reject the heat generated by the base. One proposed concept is the use of a heat pump operating with a vertical, flow-through thermal radiator mounted on a Space Station type habitation module [1]. Since the temperature of the lunar surface varies over the day, the vertical radiator sink temperatures can reach much higher levels than the comfort and even survivability requirements of a habitation module. A high temperature lift heat pump will not only maintain a comfortable habitation module temperature, but will also decrease the size of the radiators needed to reject the waste heat. Thus, the heat pump will also decrease the mass of the entire thermal system. Engineers at the Johnson Space Center (JSC) have tested a High Lift Heat Pump design and are developing the next generation heat pump based on information and experience gained from this testing.

An energy balance was performed on the life support equipment used during the Phase III, 90-day, human Lunar-Mars Life Support Test Project at the Johnson Space Center. The purpose of the analysis was to account for all the energy sources, uses, and losses in the test-bed. Knowledge from this task may allow more energy efficient designs to be developed. Control volumes were defined and energy balance equations were generated for major systems. The analyses succeeded in balancing the energy fairly well for several systems. Further, the data showed that inefficiencies existed, and means of design optimization were subsequently suggested.

A new and advanced portable life support system (PLSS) for space suit surface exploration will require a durable, compact, and energy efficient system to transport the ventilation stream through the space suit. Current space suits used by NASA circulate the ventilation stream via a ball-bearing supported centrifugal fan. As NASA enters the design phase for the next generation PLSS, it is necessary to evaluate available technologies to determine what improvements can be made in mass, volume, power, and reliability for a ventilation transport system. Several air movement devices already designed for commercial, military, and space applications are optimized in these areas and could be adapted for EVA use. This paper summarizes the efforts to identify and compare the latest fan and bearing technologies to determine candidates for the next generation PLSS.

We have completed preliminary tests that show the feasibility of an innovative concept for a spacesuit thermal control system using a lightweight, flexible heat pump/radiator. The heat pump/radiator is part of a regenerable LiCI/water absorption cooling device that absorbs an astronaut's metabolic heat and rejects it to the environment via thermal radiation at a relatively high temperature. We identified key design specifications for the system, demonstrated that it is feasible to fabricate the flexible radiator, measured the heat rejection capability of the radiator, and assessed the effects on overall mass of the PLSS. We specified system design features that will enable the flexible absorber/radiator to operate in a wide range of space exploration environments. The materials used to fabricate the flexible absorber/radiator samples were all found to be low off-gassing and many have already been qualified for use in space.

In a crewed spacecraft environment, atmospheric carbon dioxide (CO2) and moisture control are crucial. Hamilton Sundstrand has developed a stable and efficient amine-based CO2 and water vapor sorbent, SA9T, that is well suited for use in a spacecraft environment. The sorbent is efficiently packaged in pressure-swing regenerable beds that are thermally linked to improve removal efficiency and minimize vehicle thermal loads. Flows are controlled with a single spool valve. This technology has been baselined for the new Orion spacecraft, but additional data was needed on the operational characteristics of the package in a simulated spacecraft environment. One unit was tested with simulated metabolic loads in a closed chamber at Johnson Space Center during the latter part of 2006. Those test results were reported in a 2007 ICES paper.

The Sublimator Driven Coldplate (SDC) is a unique piece of thermal control hardware that has several advantages over a more traditional thermal control system. The principal advantage is the possible elimination of a pumped fluid loop, potentially saving mass, power, and complexity. Because this concept relies on evaporative heat rejection techniques, it is primarily useful for short mission durations. Additionally, the concept requires a conductive path between the heat-generating component and the heat rejection device. Therefore, it is mostly a relevant solution for a vehicle with a relatively low heat rejection requirement and/or short transport distances. Tests were performed on coupons and an Engineering Development Unit (EDU) at NASA's Johnson Space Center to better understand the basic operational principles and to validate the analytical methods being used for the SDC development.

The aim of this study was to explore if fingernail delamination injury following EMU glove use may be caused by compression-induced blood flow occlusion in the finger. During compression tests, finger blood flow decreased more than 60%, however this occurred more rapidly for finger pad compression (4 N) than for fingertips (10 N). A pressure bulb compression test resulted in 50% and 45% decreased blood flow at 100 mmHg and 200 mmHg, respectively. These results indicate that the finger pad pressure required to articulate stiff gloves is more likely to contribute to injury than the fingertip pressure associated with tight fitting gloves.

In the design of a new space suit it is necessary to have requirements that define what mobility space suit joints should be capable of achieving in both a system and at the component level. NASA elected to divide mobility into its constituent parts -- range of motion (ROM) and torque -- in an effort to develop clean design requirements that limit subject performance bias and are easily verified. Unfortunately, the measurement of mobility can be difficult to obtain. Current technologies, such as the Vicon motion capture system, allow for the relatively easy benchmarking of range of motion (ROM) for a wide array of space suit systems. The ROM evaluations require subjects in the suit to accurately evaluate the ranges humans can achieve in the suit. However, when it comes to torque, there are significant challenges for both benchmarking current performance and writing requirements for future suits.

The first concept and early experiments of a mechanical counter pressure (MCP) spacesuit were published by Webb in the late 1960's. MCP provides an alternative approach to the conventional full pressure suit that bears some significant advantages, such as increased mobility, dexterity, and tactility. The presented ongoing research provides a thorough investigation of the physiological effect of mechanical counter pressure applied onto the human skin. In this study, we investigated local microcirculatory effects produced with negative and positive ambient pressure on the lower body as a preliminary study for a lower body garment. The data indicates that the positive pressure was less tolerable than negative pressure. Lower body negative and positive pressure cause various responses in skin blood flow due to not only blood shifts but also direct exposure to pressure differentials.

Engineers at the Johnson Space Center (JSC) are using innovative strategies to design the TCS for the Bio-regenerative Planetary Life Support Systems Test Complex (BIO-Plex), a regenerative advanced life support system ground test bed. This paper provides a current description of the BIO-Plex TCS design, testing objectives, analyses, descriptions of the TCS test articles expected to be tested in the BIO-Plex, and forward work regarding TCS. The TCS has been divided into some subsystems identified as permanent “infrastructure” for the BIO-Plex and others that are “test articles” that may change from one test to the next. The infrastructure subsystems are the Heating, Ventilation and Air-Conditioning (HVAC), the Crew Chambers Internal Thermal Control Subsystem (CC ITCS), the Biomass Production Chamber Internal Thermal Control Subsystem (BPC ITCS), the Waste Heat Distribution Subsystem (WHDS) and the External Thermal Control Subsystem (ETCS).