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More than 44% of all automotive crashes occur in intersections. These incidents in intersections result in more than 8,500 fatalities and approximately 1 million injuries each year in USA. It is also established that roundabouts are safer than junctions. According to a USDOT study, when compared with the junctions they replaced, roundabouts have 40% fewer vehicle collisions, 80% fewer injuries and 90% fewer serious injuries and fatalities. In earlier work, we have proposed a family of vehicular network protocols, which use Dedicated Short Range Communications (DSRC) and Wireless Access in Vehicular Environment (WAVE) technologies to coordinate a vehicle's movement through intersections. We have shown that vehicle-to-vehicle (V2V) communications can be used to avoid collisions at the intersection and also significantly decrease the trip delays introduced by traffic lights and stop signs.

We compare two methods for life cycle analysis: the conventional SETAC-EPA approach and Economic Input-Output Life Cycle Analysis (EIO-LCA). The methods are compared for steel versus plastic fuel tank systems and for the entire life cycle of an automobile, from materials extraction to end of life. The EIO-LCA method gives comparable results for the data common to the two methods. EIO-LCA gives more detailed data, specifies the economy wide implications, and is much quicker and less expensive to implement.

Vehicle inspection in repair shops is often still based on paper forms. Information Technology (IT) does not yet support the entire inspection process. In this paper, we introduce a small wearable IT device that is controlled by speech and enables service technicians to wirelessly access relevant data and to perform on-site communication. Users can carry this device in a pocket and use a small headset to enter speech and receive audio feedback. This system provides a completely speech-enabled functionality and thus offers a hands-free operation. After showing the applicability of wearable computers in this environment, we developed a proprietary hardware system consisting of a thin-client connected via a Digital Enhanced Cordless Telecommunications (DECT) link to a standard Personal Computer (PC) that runs a speech engine and hosts a database. Several field tests in garages helped us during the evolution of our prototypes where service technicians critiqued the prototypes.

Pressure-sensitive paint (PSP) technology is a technique used to experimentally determine surface pressures on models during wind tunnel tests. The key to this technique is a specially formulated pressure-sensitive paint that responds to, and can be correlated with the local air pressure. Wind tunnel models coated with pressure-sensitive paint are able to yield quantitative pressure data on an entire model surface in the form of light intensity values in recorded images. Quantitative results in terms of pressure coefficients (Cp) are obtained by correlating PSP data with conventional pressure tap data. Only a small number of surface taps are needed to be able to obtain quantitative pressure data with the PSP method. This technique is gaining acceptance so that future automotive wind tunnel tests can be done at reduced cost by eliminating most of the expensive pressure taps from wind tunnel models.

Spray penetration for Diesel injectors, where injection pressure varies with time during the injection period, was calculated. In order to carry out this calculation, the discharge coefficients of the needle-seat opening passage and discharge hole in orifice-type Diesel nozzles were investigated separately. Simple empirical correlations were obtained between these coefficients and needle lift. Then, by introducing these correlations, the injection pressure, which is defined as the pressure in the sac chamber just upstream of the discharge hole, was either derived from measured fuel supply line pressure, or predicted by means of an injection system simulation. Finally, based on the transient injection pressure, spray tip penetration was calculated by taking the overall line which covers the trajectories of all fuel elements ejected during the injection period.

Battery life and performance depend strongly on temperature; thus there exists a need for thermal conditioning in plug-in vehicle applications. The effectiveness of thermal management in extending battery life depends on the design of thermal management used as well as the specific battery chemistry, cell and pack design, vehicle system characteristics, and operating conditions. We examine the case of an air cooled plug-in hybrid electric vehicle battery pack with cylindrical LiFePO4/graphite cell design and address the question: How much improvement in battery life can be obtained with passive air cooling? To answer this question, a model is constructed consisting of a thermal model that calculates temperature change in the battery and a degradation model that estimates capacity loss. A driving and storage profile is constructed and simulated in two cities - Miami and Phoenix - which have different seasonal temperatures.

The nitrogen dioxide (NO₂) emissions of compression ignition diesel engines are usually relatively small, especially when operated at medium and high loads. Recent experimental investigations have suggested that adding hydrogen (H₂) into the intake air of a diesel engine leads to a substantial increase in NO₂ emissions. The increase in NO₂ fraction in the total NOx is more pronounced at lower engine load than at medium- and high-load operation, especially when a small amount of H₂ is added. However, the chemistry causing the increased NO₂ formation in H₂-diesel dual-fuel engines has not been fully explored. In the present work, kinetics of NO and NO₂ formation in a H₂-diesel dual-fuel engine are investigated using a CFD model integrated with a reduced hydrocarbon oxidation chemistry and an oxides of nitrogen (NOx) formation mechanism. A low-load and a medium-load operating condition are selected for numerical simulations.

Validating the safety of Highly Automated Vehicles (HAVs) is a significant autonomy challenge. HAV safety validation strategies based solely on brute force on-road testing campaigns are unlikely to be viable. While simulations and exercising edge case scenarios can help reduce validation cost, those techniques alone are unlikely to provide a sufficient level of assurance for full-scale deployment without adopting a more nuanced view of validation data collection and safety analysis. Validation approaches can be improved by using higher fidelity testing to explicitly validate the assumptions and simplifications of lower fidelity testing rather than just obtaining sampled replication of lower fidelity results. Disentangling multiple testing goals can help by separating validation processes for requirements, environmental model sufficiency, autonomy correctness, autonomy robustness, and test scenario sufficiency.

This paper discusses the status of a government and industrially sponsored research and development program on drive train torsional vibration. Phase I of the program was completely sponsored by the U.S. Navy. During Phase I, a computer code was developed at Carnegie Mellon University for calculating the torsional response of small craft and ship drive trains. In addition, the Navy has undertaken an extensive test program to measure the torsional response of drive trains during sea trials of new and re-engined ships and craft. The resulting data base has been utilized to assess the accuracy of current torsional models and provides a basis for assessing possible improvements. Phase II of the program is being pursued through a government, university, and industrial consortium.

This paper summarizes the results to date of an on-going research program being conducted by NASA in conjunction with the FAA vertical flight program office. The goal of the program is to reduce pilot workload and increase safety for rotorcraft category A terminal area procedures. Two piloted simulations were conducted on the NASA Ames Vertical Motion Simulator to examine the benefits of optimal procedures, cockpit displays, and alternate cueing methods. Measures of performance, handling qualities ratings and pilot comments indicate that such enhancements can greatly assist a pilot in handling an engine failure in the terminal area.

Research in Intelligent Transportation Systems (ITS) has been increasingly focussed on the development of Collision Avoidance Systems (CAS). A CAS would reduce the incidence of collisions by providing warnings to the driver to take evasive action. Because single vehicle roadway departures, also known as Run-off-Road (ROR) events, are a cause of a significant portion of vehicle accidents and fatalities, an effective CAS for ROR can potentially improve highway safety dramatically. The development of performance specifications for CAS for ROR events is a part of an ongoing three-phase program for NHTSA (National Highway Traffic Safety Administration). This paper focusses on the development and application of a powerful simulation tool, RORSIM, for CAS assessments over a wide range of environmental, roadway, driver, vehicle and CAS operating conditions. The results of CAS effectiveness studies are presented.

Hover and ground-effect tests were conducted with the Lockheed-Martin Large Scale Powered Model (LSPM) during June-November 1995 at the Outdoor Aerodynamics Research Facility (OARF) located at NASA Ames Research Center. This was done in support of the Joint Strike Fighter (JSF) Program being lead by the Department of Defense. The program was previously referred to as the Joint Advanced Strike Technology (JAST) Program. The tests at the OARF included: engine thrust calibrations out of ground effect, measurements of individual nozzle jet pressure decay characteristics, and jet-induced hover force and moment measurements in and out of ground effect. The engine calibrations provide data correlating propulsion system throttle and nozzle settings with thrust forces and moments for the bare fuselage with the wings, canards, and tails removed. This permits measurement of propulsive forces and moments while minimizing any of the effects due to the presence of the large horizontal surfaces.

We compare the life cycle inventories of near–term fuel–propulsion technologies. We analyze fossil fuels (conventional and reformulated gasolines, low sulfur diesel, and compressed natural gas (CNG)), ethanol from biomass, and electricity, together with internal combustion engines (port and direct injection, spark and compression ignited) and electric vehicles (battery–powered, hybrid electric, and fuel cell). The fuel economy and emissions of conventional internal combustion engines powered by gasoline continue to improve. Unless emissions of pollutants and greenhouse gases (GHG) are stringently regulated or gasoline prices more than double, gasoline powered internal combustion engines will continue to dominate the light duty fleet. Two appealing alternative fuels are CNG and biomass ethanol. CNG cars have low emissions, including GHG and the fuel is less expensive than gasoline. Biomass ethanol can be renewable and have no net carbon dioxide (CO2) emissions.

A structured process for identifying and characterizing gear noise sources, and for reducing them to acceptable levels, is discussed in this paper. The procedure comprises a series of analysis, design, and testing steps that converge to an optimized design from the perspectives of noise and sound quality. The analysis step is used to establish a baseline noise signature and identify the design and operating parameters that offer the most potential for noise reduction. A test program based on the statistical design of experiments method is then used to verify the design and to provide feedback to the designer for further refinements and improvements. The test environment, analysis and measurement methodologies, and a case study with a prototypical gearset, are each presented and discussed.

This paper describes research and development for reducing the aerodynamic drag of heavy vehicles by demonstrating new approaches for the numerical simulation and analysis of aerodynamic flow. In addition, greater use of newly developed computational tools holds promise for reducing the number of prototype tests, for cutting manufacturing costs, and for reducing overall time to market. Experimental verification and validation of new computational fluid dynamics methods are also an important part of this approach. Experiments on a model of an integrated tractor-trailer are underway at NASA Ames Research Center and the University of Southern California. Companion computer simulations are being performed by Sandia National Laboratories, Lawrence Livermore National Laboratory, and California Institute of Technology using state-of- the-art techniques, with the intention of implementing more complex methods in the future.

High demands on advanced safety and driving functions, such as active safety and lane departure warnings, increase a vehicle's dependency on automotive electrical/electronic architectures. Hard real-time requirements and high reliability constraints must be satisfied for the correct functioning of these safety-critical features, which can be achieved by using the AUTOSAR (Automotive Open System Architecture) standard. The AUTOSAR standard was introduced to simplify automotive system design while offering inter-operability, scalability, extensibility, and flexibility. The current version of AUTOSAR does not assist in the replication of tasks for recovering from task failures. Instead, the standard assumes that architecture designers will introduce custom extensions to meet such reliability needs. The introduction of affordable techniques with predictable properties for meeting reliability requirements will prove to be very valuable in future versions of AUTOSAR.

This paper summarizes some of the environmental and economic requirements of providing the infrastructure for alternative fuel vehicles (AFV) at a large scale in the U.S. Major components of the necessary infrastructure are fuel extraction and processing plants, and fuel storage, transportation, distribution and retail systems. The type of fuel, market penetration rates, economies of scale, timely availability, longevity, and refueling mode are key to the assessment of the necessary infrastructure. Some of the infrastructure is already in place, while substantial investments will still be needed. Alcohol fuels could utilize components of the current infrastructure, with modifications, but natural gas and electric vehicles would require substantial new investments into the infrastructure.

Three alternatives to internal combustion vehicles currently being researched, developed, and commercialized are electric, hybrid electric, and fuel-cell vehicles. A total life-cycle inventory for an alternative vehicle must include factors such as the impacts of car body materials, tires, and paints. However, these issues are shared with gasoline-powered vehicles; the most significant difference between these vehicles is the power source. This paper focuses on the most distinct and challenging aspect of alternative-fuel vehicles, the power sources. The life-cycle impacts of battery systems for electric and hybrid vehicles are assessed. Less data is publicly available on the fuel cell; however, we offer a preliminary discussion of the environmental issues unique to fuel cells. For each of these alternative vehicles, a primary environmental hurdle is the consumption of materials specific to the power sources.

The paper analyzes energy use and emissions per GJ of various fuels delivered to the vehicle fuel tank, covering extraction, fuel production, transportation, storage, and distribution phases of the life cycle of alternative fuels. Drawing on a number of existing studies, the modeling issues and approaches, main results and insights are summarized. The range of estimates in various studies is large; however, common patterns can be observed. The analysis indicates, that conventional gasoline fuel cycle has robust advantages with respect to energy efficiency, conventional pollutant emissions, and most importantly, existing infrastructure compared to alternative fuels. Fossil fuel based alternatives like CNG, NG–Methanol, NG–FTL do not result in significant improvement in fuel cycle environmental performance. Biofuels offer the benefits of lower and even negative GHG emissions, sustainability, and domestic fuel production.

This paper describes research and development for reducing the aerodynamic drag of heavy vehicles by demonstrating new approaches for the numerical simulation and analysis of aerodynamic flow. Experimental validation of new computational fluid dynamics methods are also an important part of this approach. Experiments on a model of an integrated tractor-trailer are underway at NASA Ames Research Center and the University of Southern California (USC). Companion computer simulations are being performed by Sandia National Laboratories (SNL), Lawrence Livermore National Laboratory (LLNL), and California Institute of Technology (Caltech) using state-of-the-art techniques.