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Validation was performed on an existing heavy truck vehicle dynamics computer model with roll stability control (RSC). The first stage in this validation was to compare the response of the simulated tractor to that of the experimental tractor. By looking at the steady-state gains of the tractor, adjustments were made to the model to more closely match the experimental results. These adjustments included suspension and steering compliances, as well as auxiliary roll moment modifications. Once the validation of the truck tractor was completed for the current configuration, the existing 53-foot box trailer model was added to the vehicle model. The next stage in experimental validation for the current tractor-trailer model was to incorporate suspension compliances and modify the auxiliary roll stiffness to more closely model the experimental response of the vehicle. The final validation stage was to implement some minor modifications to the existing RSC model.

One obstacle hindering the use of port fuel injection in natural gas engines is poor idle performance due to incomplete mixing of the cylinder charge prior to ignition. Fuel injection timing has a strong influence on the mixing process. The purpose of this work is to determine the impact of fuel injection timing on in-cylinder fuel distribution. Equivalence ratio maps have been acquired by Planar Laser Induced Fluorescence in an optical engine with a production cylinder head. Experimental results have been used to determine the injection timing which produces the most uniform fuel distribution for the given engine.

This paper presents progress, to date, on development and evaluation of three front seat airbag restraint systems for small cars. The subject vehicles were a Chevrolet Chevette, for which a passenger restraint system was developed, and a Dodge Omni, for which both driver and passenger systems were developed. The systems were primarily evolved during a series of sled tests and evaluated in vehicle barrier impacts.

This paper describes the results of a 2 year study into the field accident performances of two basic designs of energy-absorbing steering assemblies. The two basic designs are the axial-collapse type of steering column used in conjunction with a shear capsule and the self-aligning energy-absorbing steering wheel mounted on a nonstroking column. The study identifies major injury causation factors for these two types of steering assemblies. The analysis was performed on 161 accident cases selected for unrestrained drivers in frontal accidents in two vehicle types.

In the last twelve years, the overwhelming effectiveness of restraining children in the United States, Canada and Europe has been proven in reducing death and injury in automobile accidents. Despite the proven benefits of restraining children, one type of injury has not been prevented. This paper is an analysis of stretch injuries to the spinal cord in the upper thoracic or cervical spine. This paper discusses, in general, spinal cord injuries from a biomechanical point of view. The relationship between various loading conditions and the resulting types of spinal cord injuries is discussed. This paper also examines seven real world automobile accidents. Information for each case includes: vehicles involved, type of roadway, crash Delta-V, occupant direction of motion, restraint type, injuries to occupants, and anthropometry of child with spinal cord injury. A description and location of each spinal cord injury that occurred at the time of the accident is discussed.

This paper summarizes the rationale used to specify the geometric, inertial and impact response requirements for a small adult female dummy and a large adult male dummy with impact biofidelity and measurement capacity comparable to the Hybrid III dummy, the most advanced midsize adult male dummy. Body segment lengths and weights for these two dummies were based on the latest anthropometry studies for the extremes of the U.S.A. adult population. Other characteristic body segment dimensions were calculated from geometric and mass scaling relationships that assured that each body segment had the same mass density as the corresponding body segment of the Hybrid III dummy. The biomechanical impact response requirements for the head, neck, chest and knee of the Hybrid III dummy were scaled to give corresponding biomechanical impact response requirements for each dummy.

In 2007, a software model of a Roll Stability Control (RSC) system was developed based on test data for a Volvo tractor at NHTSA's Vehicle Research and Test Center (VRTC). This model was designed to simulate the RSC performance of a commercially available Electronic Stability Control (ESC) system. The RSC model was developed in Simulink and integrated with the available braking model (TruckSim) for the truck. The Simulink models were run in parallel with the vehicle dynamics model of a truck in TruckSim. The complete vehicle model including the RSC system model is used to simulate the behavior of the actual truck and determine the capability of the RSC system in preventing rollovers under different conditions. Several simulations were performed to study the behavior of the model developed and to compare its performance with that of an actual test vehicle equipped with RSC.

The use of vehicle damage measurements has been proven to be an effective technique in the determination of impact energy and pre-collision speeds. However, as with any analytical technique, the quality of the speed estimate is highly dependent on the accuracy of the measurements. This relationship suggests a need to employ intricate and exacting measurement schemes to obtain useable data. This approach is often difficult to implement in a routine accident investigation where a tape measure may be the only available measuring device. In the current study, vehicle damage resulting from collisions with a known speed is measured with techniques of increasing sophistication and the results are compared. These measurements are then used in conjunction with the CRASH III computer program to estimate the pre-impact vehicle speeds. The analysis technique used by CRASH III is also reviewed to provide a summary understanding of how the crush measurements are used in the program.

Pedestrian research and testing at the NHTSA Vehicle Research and Test Center has recently focused on assessment of proposed ISO and EEVC head impact test procedures, and extension of these procedures to additional vehicle frontal surfaces. In addition to test parameter sensitivity evaluation, reconstruction of PCDS (Pedestrian Crash Data Study) cases with laboratory impact tests and computer simulations has been conducted. This paper presents the results of this research.

All fifty states and the District of Columbia have laws requiring children under specified ages to be restrained in an infant restraint system, a toddler restraint system, or an adult seat belt. The child restraint systems are regulated through Federal Motor Vehicle Safety Standard (FMVSS) 2 13 Child Restraint Systems. The adult seat belts are regulated through FMVSS 208, Occupant Crash Protection, FMVSS 209. Seat Belt Assemblies, and FMVSS 210. Seat Belt Assembly Anchorages. The combination of differing laws for the fifty states and the District of Columbia, four “rather ambiguous” federal regulations, and recommendations on child restraint and seat belt usage by various safety-conscious groups in the private sector, as well as various foreign countries leads to total stupefaction. This paper outlines and discusses state laws, federal standards and private sector recommendations. The paper also analyzes the interaction between children and adult 2- and 3-point belts in automobiles.

ORVR (Onboard Refueling Vapor Recovery) canisters trap vapors during normal operations of a vehicle's engine, and during refueling. This study evaluates the relative risks involved should a canister rupture in a crash. A canister impactor was developed to simulate real-world impacts and to evaluate the canisters' rupture characteristics. Numerous performance aspects of canisters were evaluated: the energy required to rupture a canister; the spread of carbon particles following rupture; the ease of ignition of vapor-laden particles; the vapor concentration in the area of ruptured, vapor-laden canisters; and the potential of crashes to rupture and ignite canisters. Results from these five items were combined into a risk analysis.

A technique has been developed to study the effects of the vehicle interior on the performance of child safety seats. Child safety seat sled tests are used to define the kinematics of the seat and child in a crash situation. Computer animation of this motion is superimposed on the motion of the actual vehicle crash tests giving an estimation of the kinematics of the child and child seat in a real crash situation. The significance of the vehicle interior and the interference of the vehicle interior with the child's kinematics is presented within the computer animation. The analysis is conducted using a single child restraint device in multiple seating conditions within a single vehicle.

Crankshaft angular position measurements are fundamental to all modern automotive engines. These measurements are required to control fuel injection timing as well as ignition timing. However, many other functions can be performed from such measurements through the use of advanced signal processing. These additional functions are essentially diagnostic in nature although there is potential for substitution of primary fuel and ignition control functions. This paper illustrates the application of crankshaft angular position measurement to the estimation of individual cylinder indicated and/or brake torque in IC engines from measurement of crankshaft position/velocity.

This paper presents the results of an in-depth study of the measurement of occupant kinematic response on the S-E-A Roll Simulator. This roll simulator was built to provide an accurate and repeatable test procedure for the evaluation of occupant protection and restraint systems during roll events within a variety of occupant compartments. In the present work this roll simulator was utilized for minimum-energy, or threshold type, rollover events of recreational off-highway vehicles (ROVs). Input profiles for these tests were obtained through a separate study involving autonomous full vehicle tests [1]. During simulated roll events anthropomorphic test device (ATD) responses were measured using on-board high speed video, an optical three-dimensional motion capture system (OCMS) and an array of string potentiometers.

Flow fields generated during the intake stroke of a 4-stroke I.C. engine are studied experimentally using water analog simulation. The fluid is seeded by small flow tracer particles and imaged by two digital cameras at BDC. Using a 3-D Particle Tracking Velocimetry technique recently developed, the 3-D motion of these flow tracers is determined in a completely automated way using sophisticated image processing and PTV algorithms. The resulting 3-D velocity fields are ensemble averaged over a large number of successive cycles to determine the mean characteristics of the flow field as well as to estimate the turbulent fluctuations. This novel technique was applied to three different cylinder head configurations. Each configuration was run for conditions simulating idle operation two different ways: first with both inlet ports open and second with only the primary port open.

In order to evaluate a human surrogate, the human and surrogate response must be defined. The purpose of this study was to evaluate the response of cadaver subjects to blunt impacts to the frontal bone, nasal bone and maxilla. Force-displacement corridors were developed based on the impact response of each region. Variation in the force-displacement response of the cadaver subjects due to the occurrence of fracture and fracture severity was demonstrated. Additionally, impacts were performed at matched locations using the Facial and Ocular CountermeasUre Safety (FOCUS) headform. The FOCUS headform is capable of measuring forces imposed onto facial structures using internal load cells. Based on the tests performed in this study, the nasal region of the FOCUS headform was found to be the most sensitive to impact location. Due to a wide range in geometrical characteristics, the nasal impact response varied significantly, resulting in wide corridors for human response.

Objectives. Examination of head injuries in the Pedestrian Crash Data Study (PCDS) indicates that many pedestrian head injuries are induced by a combination of head translation and rotation. The Simulated Injury Monitor (SIMon) is a computer algorithm that calculates both translational and rotational motion parameters relatable head injury. The objective of this study is to examine how effectively HIC and three SIMon correlates predict the presence of either their associated head injury or any serious head injury in pedestrian collisions. Methods. Ten reconstructions of actual pedestrian crashes documented by the PCDS were conducted using a combination of MADYMO simulations and experimental headform impacts. Linear accelerations of the head corresponding to a nine-accelerometer array were calculated within the MADYMO model's head simulation.

One of the greatest challenges faced in the design of realistic occupant protection systems is an accurate statistical model of what is really needed. The paucity of data is this realm hinders designers of standards alike. Ideally, a model of crash statistics would correlate, for significant accident modes, injury level (as measured by AMA Abreviated Injury Scale “AIS”) with some adequate measure of crash intensity. Having this information, not only could the required level of safety design be ascertained, but also the justifiable economic expenditure could be estimated. This paper treats the statistical basis for deployment of a data retrival system. It provides a basis for estimates of the amount of data required, the number of vehicles to be instrumented, the crash severity trigger levels, and the economics of recorder installation, for various levels of injury and fatality.

This paper presents a feedback linearization control technique as applied to a Roll Simulator. The purpose of the Roll Simulator is to reproduce in-field rollovers of ROVs and study occupant kinematics in a laboratory setting. For a system with known parameters, non-linear dynamics and trajectories, the feedback linearization algorithm cancels out the non-linearities such that the closed-loop dynamics behave in a linear fashion. The control inputs are computed values that are needed to attain certain desired motions. The computed values are a form of inverse dynamics or feed-forward calculation. With increasing system eigenvalue, the controller exhibits greater response time. This, however, puts a greater demand on the translational actuator. The controller also demonstrates that it is able to compensate for and reject a disturbance in force level.

There is currently a large effort in industry to make natural gas a viable alternative fuel for internal combustion engines. While the use of natural gas offers several advantages such as reduced emissions and potentially higher efficiency, it also has some inherent difficulties. Among these is the challenge of producing a consistently homogeneous air/fuel mixture while retaining the advantages which accompany modern, multi-point, fuel injection systems. The purpose of the research described here is to investigate the in-cylinder mixture formation process in a port injected natural gas fueled engine. Planar laser-induced fluorescence has been used to produce qualitative air fuel ratio maps in the engine cylinder, in selected planes, throughout the intake and compression strokes. The process consists of impinging a sheet of ultraviolet laser light on various planes parallel to, and normal to, the cylinder axis.