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Current state-of-the-art vehicles implement pedestrian protection features that rely on pedestrian detection sensors and algorithms to trigger when impacting a pedestrian. During the development phase, the vehicle must “learn” to discriminate pedestrians from the rest of potential impacting objects. Part of the training data used in this process is often obtained in physical tests utilizing legform impactors whose external biofidelity is still to be evaluated. This study uses THUMS as a reference to assess the external biofidelity of the most commonly used impactors (Flex-PLI, PDI-1 and PDI-2). This biofidelity assessment was performed by finite element simulation measuring the bumper beam forces exerted by each surrogate on a sedan and a SUV. The bumper beam was divided in 50 mm sections to capture the force distribution in both vehicles. This study, unlike most of the pedestrian-related literature, examines different impact locations and velocities.

Power steering systems provide significant design challenges. They are detrimental to fuel economy since most require the continuous operation of a hydraulic pump. This generates heat that must be dissipated by fluid lines and heat exchangers. This paper presents a simple one-dimensional transient model for power steering components. The model accounts for the pump power, heat dissipation from fluid lines, the power steering cooler, and the influence of radiation heat from exhaust system components. The paper also shows how to use a transient thermal model of the entire system to simulate the temperatures during cyclic operation of the system. The implications to design, drive cycle simulation, and selection of components are highlighted.

In 1972, the first SAE paper describing the use of computer simulation as a design tool for automotive air conditioning was written by these authors. Since then, many such simulations have been used and new tools such as CFD have been applied to this problem. This paper reviews the work over that past 35 years and presents several of the improvements in the basic component and system models that have occurred. The areas where “empirical” information is required for model support and the value of CFD cabin and external air flow modeling are also discussed.

Recently there has been a greater awareness of the increased risk of certain injuries associated with air bag deployment, especially the risks to small occupants, often women. These injuries include serious eye and upper extremity injuries and even fatalities. This study investigates the interaction of a deploying air bag with cadaveric upper extremities in a typical driving posture; testing concentrates on female occupants. The goals of this investigation are to determine the risk of upper extremity injury caused by primary contact with a deploying air bag and to elucidate the mechanisms of these upper extremity injuries. Five air bags were used that are representative of a wide range of air bag ‘aggressivities’ in the current automobile fleet. This air bag ‘aggressivity’ was quantified using the response of a dummy forearm under air bag deployment.

The poisoning of three way catalysts (TWC) by the phosphorus contained in oil formulations containing zinc dialkyldithiophosphate (ZDDP) is examined. Catalysts were exposed to various types of ZDDP and detergents under conditions that were known to reduce performance through phosphorus poisoning without the blocking of sites by formation of glazing. The presence of phosphorus was detected with energy dispersive x-ray spectroscopy (EDX). In addition to analyzing the surface concentration of the phosphorus on the washcoat, the catalyst was cross cut so phosphorus that diffused into the washcoat could be mapped. The total phosphorus in the catalyst could then be calculated. The amount of total phosphorus detected correlated well with the reduced activity of the catalyst as measured by the temperature of 50% conversion.

This paper evaluates the biofidelity of the Hybrid III 5th percentile female dummy relative to seven small female cadavers tested as out-of-position drivers in static air bag deployment tests. In the out-of-position tests, the chest was positioned against the air bag module in an effort to recreate a worst-case loading environment for the thorax. Two pre-depowered production air bags and a prototype dual-stage air bag were evaluated. Thoracic accelerometers and chestbands were used to compare chest compression, velocity, acceleration, and Viscous Criteria. A statistical comparison of dummy and cadaver results indicate acceptable biofidelity of the Hybrid III dummy with significant differences observed only in the Viscous Criteria.

The Cummins M-11 high soot diesel engine test is a key tool in evaluating lubricants for the new PC-7 (CH-4) performance category. M-11 rocker arms and crossheads from tests with a wide range of lubricant performance were studied by surface analytical techniques. Abrasive wear by primary soot particles is supported by the predominant appearance of parallel grooves on the worn parts with their widths matching closely the primary soot particle sizes. Soot abrasive action appears to be responsible for removing the protective antiwear film and, thus, abrades against metal parts as well. Subsequent to the removal of the antiwear film, carbide particles, graphite nodules, and other wear debris are abraded, either by soot particles or sliding metal-metal contact, from the crosshead and rocker arm metal surfaces. These particles further accelerate abrasive wear. In addition to abrasive wear, fatigue wear was evident on the engine parts.

One Dimensional models for front end air flows through the cooling system package are very useful for evaluating the effects of component and front end geometry changes. To solve such models for the air flow requires a robust iterative process that involves a number of non-linear sub-models. The cooling fan (s) constitute a major part of the difficulty, especially when they employ a viscous or “thermal” fan drive. This drive varies the torque coupling between the input and output shafts based on the radiator outlet air temperature. The coupling is achieved by viscous shear between two grooved disks and is regulated by a bimetal strip valve that varies the amount of fluid between the disks. This paper presents a mathematical model by which the input/output speed ratio may be determined as a function of the air temperature and input speed. Coefficients in the model are estimated from standard supplier performance information.

Simple component models are advantageous when simulating vehicle AC systems so that overall model complexity and computation time can be minimized. These models must be robust enough to avoid instability in the iteration method used for determining the AC system operating or “balance” point. Simplicity and stability are especially important when the AC system model is coupled with a vehicle interior model for studies of transient performance because these are more computationally intensive. This paper presents a semi-empirical modeling method for compressors based on dimensionless parameters. Application to some sample compressor data is illustrated. The model equations are simple to employ and will not introduce significant stability problems when used as part of a system simulation.

Pediatric Anthropomorphic Test Devices (ATDs) are valuable tools for assessing the injury mitigation capability of automotive safety systems. The neck pendulum test is widely used in biofidelity assessment and calibration of the ATD neck, and neck moment vs. angle response requirements are the metrics typically derived from the test. Herein, we describe the basis and methods for modifying the neck pendulum such that it more closely reflects base of the neck accelerations observed by a restrained three-year old ATD in a frontal crash. As a measure of base of the neck acceleration, the x-direction chest acceleration from thirty-one restrained Hybrid III three-year-old ATDs in vehicle frontal crash tests were analyzed. The standard neck pendulum yielded a mean peak acceleration that is 1.2x the peak of vehicle base of the neck accelerations, 1.6x the average, and 0.24x the duration.

The Icing Branch at NASA Glenn Research Center has funded an exploratory effort to identify requirements for developing a flight dispatcher-centered web-based icing training program that would be available for all airspace users. Through research and discussions with personnel at airlines, target areas were identified as influences on the requirements for the training system: 1 Flight dispatchers' icing related judgments and decision-making; 2 Certification, new hire and recurrent flight dispatcher training with respect to icing; 3 Icing related weather sources and the problems that flight dispatchers may have in their interpretation; 4 Pedagogical strategies (such as flight dispatcher-centered scenario-based approaches) for delivering flight dispatcher training content; and 5 Concerns/constraints with respect to web-based training for flight dispatchers.

A biaxial test procedure is used to assess the constitutive properties of polymers in tension. The constitutive constants are derived for high strain rate applications such as those associated with crashworthiness studies. The test procedure is used in conjunction with a time- and strain-dependent quasi-linear viscoelastic constitutive law consisting of a Mooney-Rivlin formulation combined with Maxwell elements. The procedure is demonstrated by describing the stress vs. strain relationship of a rubber specimen subjected to a step-relaxation input. The constitutive equation is transformed from a nonlinear convolution integral to a set of first order differential equations. These equations, with the appropriate boundary conditions, are solved numerically to obtain transient stresses in two principal directions. Material constants for use in the explicit LS-Dyna non-linear finite element code are provided.

Biomechanical data are often assumed to be doubly censored. In this paper, this assumption is evaluated critically for several previously published sets of data. Injury risk functions are compared using simple logistic regression and using survival analysis with 1) the assumption of doubly censored data and 2) the assumption of right-censored (uninjured specimens) and uncensored (injured) data. It is shown that the injury risk functions that result from these differing assumptions are not similar and that some experiments will require a preliminary assessment of data censoring prior to finalizing the experimental design. Some types of data are obviously doubly censored (e.g., chest deflection as a predictor of rib fracture risk), but many types are not left censored since injury is a force-limiting phenomenon (e.g., axial force as a predictor of tibia fracture). Guidelines for determining the censoring for various types of experiment are presented.

This paper presents a technique for developing corridors from individual subject responses contained in experimental biomechanical data sets. Force-deflection response is used as an illustrative example. The technique begins with a method for averaging human subject force-deflection responses in which curve shape characteristics are maintained and discontinuities are avoided. Individual responses sharing a common characteristic shape are averaged based upon normalized deflection values. The normalized average response is then scaled to represent the given data set using the mean peak deflection value associated with the set of experimental data. Finally, a procedure for developing a corridor around the scaled normalized average response is presented using standard deviation calculations for both force and deflection.

Heavy Duty Diesel Truck (HDDT) drivers are required by law to rest 8 hours for every 10 driving hours. As a consequence, the trucks are idled for long periods of time to heat or cool the cabin, to keep the engine warm, to run electrical appliances, and to refrigerate or heat truck cargo. This idling results in gaseous and particulate emissions, wasted fuel and is costly. Various technologies can be used to replace truck idling, including heaters, auxiliary power units, parking space electrification, and heating and air conditioning units in the parking space. In this paper the results of a life cycle analysis are reported giving the associated emissions savings and ecological burdens of these four technologies compared to truck idling. In this analysis the savings related to reduced engine maintenance and increased engine life are included. The fuel consumed and emissions produced by a truck engine at idle was obtained from experiments performed at Aberdeen Test Center (ATC).

This paper describes the development of a non-linear finite element model of a commuter category aircraft seat designed to explore the issue of energy absorption in severe, but survivable, crashes. Using a reference seat, the paper presents a description of the model and the results of finite element modeling of the seat at increasingly severe impact velocities. The paper presents the results of a parallel experimental program, conducted to validate the model, in which instrumented crash dummies were drop tested in the reference seat at the same impact velocities as the simulation. Experimental results are reported for passenger lower lumbar loading, peak pelvic acceleration, and seat structural loading.

This paper describes the development of an Enhanced Emergency Locator Transmitter (E2LT) for general aviation craft. The E2LT will supplement existing Emergency Locator Transmitter systems which broadcast a simple radio beacon in the event of an aircraft crash. Unlike existing devices, however, the E2LT device will transmit the crash site location and crash severity directly to Emergency Response Teams. The paper describes the design, development, and testing of an advanced emergency location system that combines inexpensive crash sensors, Web-enabled wireless communications and Global Positioning Systems to transmit crash site location to an Emergency Base Station. The purpose of the system is not only to shorten the time it takes for authorities to respond to the crash site, but to improve the quality of the response.

The New Jersey Department of Transportation (NJDOT) is currently sponsoring a research study at Rowan University to develop strategies for reducing diesel emissions from mobile sources such as school buses and class 8 trucks. One such source of diesel emissions results from unnecessary idling of school buses, which is a typical practice that occurs in the mornings to warm up engines and in the afternoon while bus drivers wait to pick up children for their afternoon routes. To quantify emissions and fuel consumption during idling, three school buses equipped with an International T444E, an International DT466E, and a Cummins 5.9L B series engine were instrumented and tested in an environmental chamber. To simulate a wide variety of idling situations, tests were conducted at four different ambient temperatures (20°F, 40°F, 65°F and 85°F) and relative humidity ranging from 37 to 90%.

A steady state mobile test was developed to measure the concentration of breathable particles that can enter the cabin of a school bus. The principles of experimental design were used to identify the experimental conditions for the test and to analyze the data. The design consisted of a series of steady-state tests using a 1992 International school bus. The testing was performed on a closed three mile track at the Army Test Center in Aberdeen, MD. The mass concentrations of particles smaller than 2.5 microns were measured at three locations inside the bus and at the air intake into the engine. The number concentration of particles was measured at the tailpipe. Three factors were varied at three levels in a Box-Benhken design. The steady state speed was set at 5, 30, and 55 mph. A load was applied to the engine with a mobile dynamometer to simulate a 0, 0.67% and 1.33% road grade.

This paper presents an analysis of the displacement measurement of the Hybrid III 50th percentile male dummy chest in quasistatic and dynamic loading environments. In this dummy, the sternal chest deformation is typically characterized using a sliding chest potentiometer, originally designed to measure inward deflection in the central axis of the dummy chest. Loading environments that include other modes of deformation, such as lateral translations or rotations, can create a displacement vector that is not aligned with this sensitive axis. To demonstrate this, the dummy chest was loaded quasistatically and dynamically in a series of tests. A string potentiometer array, with the capability to monitor additional deflection modes, was used to supplement the measurement of the chest slider.