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In comparison to drivers exposed to steering-wheel airbag deployments in frontal crashes, there have been fewer front-seat passengers exposed to airbag deployments for 1) many of the cars in crashes did not have dual airbags and 2) the front passenger seat is less often occupied. Of the 826 airbag crashes detailed by UMTRI crash investigators at the time of this manuscript preparation, there were 145 front-seat passengers, exposed to instrument panel mounted airbags. Most of these front-seat passengers 124 were involved in the frontal crashes. There were 92 who were 16 years of age or older, 24 were under 12 years of age and 11 young teenagers, 13-15 years of age. Of those who were 16 years or older in frontal crashes 70% had an MAIS-1 injury. None of the MAIS-2 injuries were directly related to airbag deployments. Of the AIS-3+ level injuries, about two-thirds were not airbag related.

The primary function of the Occupant Classification System is to provide reliable passenger seat occupancy information to the automobile’s central processing unit to control airbag deployment. Our Occupant Classification (OC) sensor system is based on analysis of the seat occupancy pressure profile, which discerns human like from human unlike profiles. If the occupancy is identified as a person, an allocation into one of four morphologic ranges is made. Accordingly, children, light adults, heavy children, medium adults, heavy adults, etc. can be discerned (Figure 1).

The CVT offers high fuel economy, presumably because it ensures a low BSFC driving condition with its continuously variable ratio characteristics. Focusing solely on BSFC values, i.e., indices that represent the engine's thermal efficiency, is not enough, as substantial work loss occurs in the drivetrain, including the transmission and engine accessories, from the engine to wheels. Therefore, attention needs to be paid to the efficiency of the entire powerplant, including engine and transmission, rather than just focusing on engine thermal efficiency, as has been conventionally done. Engine and CVT controls should be integrated as in addition to the stoichiometric operation, an engine may be operated in modes of lean burn and exhaust-gas recirculation. This paper describes a newly developed algorithm for the calculation of the combinations between the engine torque and CVT ratio in order to achieve the highest overall efficiency for the engine and transmission system.

The 45RFE is a new generation electronically controlled rear wheel drive transmission. It employs real-time feedback, closed-loop modulation of shift functions to achieve excellence in shift quality and to meet severe durability goals. The 45RFE uses no shift valves; all friction element applications are effected with high-flow electro-hydraulic solenoid valves. A unique gear train arrangement of three planetary carriers allows all sun and annulus gears to have identical numbers of teeth and to use common pinion gears in all carriers. This results in substantial manufacturing simplification. The three-planetary system is designed for four forward ratios of 3.00, 1.67, 1.00 and 0.75 and one reverse gear ratio equal to the low gear ratio. A fifth ratio of 1.50 is used mainly in certain kick-down shift sequences for highway passing. A sixth forward ratio, an additional overdrive ratio of 0.67, is available in the hardware.

For side airbag systems it is necessary to measure the acceleration within a time of less than 3 ms in order to inflate the side airbag in time. A new generation of side airbag sensors that uses a linear accelerometer is presented. The evaluation circuit includes amplification, temperature coefficient compensation, two wire unidirectional current interface, and a zero-offset compensation. The sensing element for the measurement of acceleration is a surface micromachined accelerometer. In order to minimise the production costs the surface micromachined sensor element and the corresponding evaluation ASIC are packaged into a standard PLCC28 housing. For the entire function only few external components are necessary. During the power-on cycle an internal selftest is carried out and the result is transmitted to the airbag control unit. Most important results of the characterisation are presented.

MANN+HUMMEL has developed a centrifugal oil cleaner focused on the separation of soot from oil. The basic setup and operation principle of a free jet driven centrifugal oil cleaner and its integration into an engine oil system will be explained. The development was supported by a new simulation tool, which predicts the centrifugal cleaner performance using computer analysis. This includes both the prediction of rotor speed and particle separation. Additionally, MANN+HUMMEL performed a detailed rotor design analysis in order to reduce torque resistance, to improve environmental protection and reduce cost.

The correct timing of the diesel injection pump on engine is of major importance for all functions of the engine and for its exhaust emissions, during production pass off as well as in the field. Within the diesel service workshops a variety of devices exist to test the timing of the injection pump on engine. Most of them operate by clamp-on transducer being fitted to the injection pipe. A large uncertainty exists concerning the accuracy of such timing systems. Most diesel engine manufacturers do not have confidence in the timing devices capability and, therefore, do not recommend their usage. A working group within the International Organization for Standardization (ISO) adopted a method for the validation of these measurement systems, which usually is used to judge the capability of measurement gauges for industrial production processes.

Current crash avoidance systems combine vehicle speed with knowledge of position (and change in position) of potential obstacles in front of the vehicle to trigger alarms warning of impending collisions. The various alarm levels are triggered using a simple set of minimum time delays. Although knowledge of on-board vehicle braking capability is not currently incorporated into these systems, such knowledge can improve the effectiveness of crash avoidance systems. A round robin test series of performance based brake testers (PBBTs) was conducted in which the brake forces on several configurations of control vehicles were measured. Using the PBBT-reported brake forces and vehicle weights, combined with knowledge of limiting tire/road coefficient of friction, the maximum deceleration potential can be determined and incorporated into on-board crash avoidance systems.

Extensive modeling and simulation studies have been carried out to evaluate the performance of systems for avoiding run-off-road crashes. Results show that the effectiveness of in-vehicle crash avoidance systems depends on how well they can be tailored to specific vehicle, driver, and roadway characteristics. To this end, a major focus of these studies is the development of improved driver lane-keeping models based on statistical analyses of data collected in driving experiments conducted on highways, rural roads, and test tracks. In recent simulation studies using improved driver models, the performance of crash avoidance systems in tractor-trailers and passenger cars has been compared over a wide range of incipient run-off-road crash conditions. Heavy trucks present a greater challenge for run-off-road crash avoidance systems, because they slightly but frequently leave the lane even under controlled driving, and because they are less stable during recovery maneuvers.

This paper deals with the steering system with conventional round steering-wheel from the view point of Steer-by-Wire system design. Steering gear ratio and control force characteristics are selected as interface variables of the steering system. The concept of ideal steering gear ratio which is derived on the basis of mapping of steering wheel angle and vehicle path angle is proposed to determine steering gear ratio. Simulator experiments are conducted to investigate the effects of interface variables on system and driver’s control performance. Validity of proposed ideal steering gear ratio would be confirmed. Candidates for objective task performance measure to define desirable control force characteristics would be determined from the test results.

This paper describes the concept of using state space boundaries to evaluate the safety effects of longitudinal collision avoidance systems from data produced in field operational tests. The boundaries are represented in terms of the relative range and range rate between a lead vehicle and the vehicle hosting the collision avoidance system. Phase plane diagrams are used to illustrate the state space boundaries. Parameters of curves representing the boundaries were selected such that the boundaries would be fairly well distributed over the range vs. range-rate space with the ones closer to the horizontal axis (range = 0) being indicative of a relatively higher hazard potential. The application of these state space boundaries is examined with data available from a recently completed field operational test sponsored by the National Highway Traffic Safety Administration.

Dynamically-distinct precrash scenarios in rear-end collisions were identified in a recent study conducted by the Volpe National Transportation Systems Center, of the United States Department of Transportation, Research and Special Programs Administration, in conjunction with the National Highway Traffic Safety Administration (NHTSA) using NHTSA's General Estimates System (GES) crash database from 1992 through 1996. Precrash scenarios represent vehicle dynamics immediately prior to a collision. This paper provides a statistical description of the five most frequently-occurring rear-end precrash scenarios in terms of vehicle and driver characteristics, using the 1996 GES database.

Veridian, Calspan Operations is currently developing an on-vehicle threat detection system for intersection collision avoidance (ICA) as part of its ICA program with the National Highway Traffic Safety Administration. This paper briefly reviews the system design and describes recent efforts that include the development of a multi-radar collision avoidance (C/A) system. Results from in-traffic experiments utilizing two radars to simultaneously observe crossroads traffic from both directions will be presented for the first time. Warning functions were applied to the data in real time and for non-real-time signal processing. These functions warn the ICA vehicle against entering the intersection when targets are predicted to be present. This research demonstrates the feasibility of preventing many intersection collisions.

This paper summarizes the activities and results of a preliminary human factors review for the Intelligent Vehicle Initiative (IVI) Program. The objective of the project was to identify human factors work that needs to be done early in the life cycle of the IVI program to ensure safe and well-engineered vehicles. This project was comprised of two major subtasks. Subtask 1 provided for a “Preliminary IVI Human Factors Technology Workshop” to draw together the stakeholders in the IVI program and define the technologies and the human factors issues that should be considered in developing an IVI. Subtask 2 investigated the preliminary infrastructure and human factors in-vehicle requirements for alternative candidate configurations of an IVI.

The unsteady near wake of a ground vehicle body was investigated using hot wire anemometry and an unsteady pressure measurement system. A three dimensional bluff body model was used to simulate the time dependent, three dimensional near wake flow field generated by trucks, buses, and automobiles. Coherence and coherence phase were effective methods to analyze the unsteady pressure field and to relate different pressure signals. Spectral analysis of the velocity and pressure signals was used to identify periodic wake flow structures. The time averaged near wake contains a ring vortex enclosed by shear layers which start where the model boundary layer separates from the body. At the start of the shear layer, vortex shedding was measured at a dimensionless frequency, StH(shed) = 1.157. As these vortices convected along the shear layer, vortex pairing was observed which approximately halves the characteristic frequency.

Avoiding low-frequency pressure pulsations and establishing a good axial static pressure distribution are primary concerns for open jet wind tunnels. The current research was conducted to ensure the full scale Chrysler Aero-Acoustic Wind Tunnel (AAWT) design is consistent with good performance in these two areas. Experiments were conducted in two tunnels: a 1/3.6-scale closed-circuit tunnel and a 1/12-scale open-loop tunnel. Results from both are consistent, and a configuration that exhibits i) minimal pulsations for both empty test section and 15% vehicle blockage and ii) a good axial static pressure distribution has been identified for the AAWT. The results illustrate the effect of open jet length, collector geometry, and plenum geometry on pulsation levels and highlight the spatial variation of the pulsation levels within the plenum chamber. Pulsation levels were observed to increase with increasing open jet length and decreasing collector throat area.

This paper describes a system for measuring unsteady pressure at up to 256 spatial points and at frequencies up to 300 Hz. The system consists of commercially available equipment for measuring steady pressures. It is based on the use of electronically scanned pressure (ESP) sensors, 16 A/D converters, and a personal computer to control the whole system and acquire data. The signal outputs through the tubes connecting the pressure taps and the ESP sensors are compensated, as are the phase delays between the scanned signals and the gain variation. A 1/5 scale model of a sedan was used in this experiment. The passenger car model was placed in a wind tunnel equipped with a moving belt, which was operated at the same speed as the uniform flow in the wind tunnel. Pressure measurements were obtained at 252 points in a plane behind the model perpendicular to the uniform flow. Measurements were made with the belt turned on and off.

An improved technique is described for the experimental modeling of transient cross wind gust influences on passenger vehicles. The new configuration uses a set of vertical axis shutters which open and close in a ‘Mexican wave’ fashion to scan the cross wind jet along the working section of the wind tunnel. The new arrangement dramatically increases the rate at which experiments can be performed and offers the opportunity to apply phase-averaging techniques to multiple data sets in order to reduce noise. This is a significant development as most previous test methods have suffered from poor signal to noise ratios. Experimental results are presented for transient surface pressure measurements on a simplified vehicle model which clearly demonstrate the benefits of the new technique.

A new method for processing data from time-accurate point measurements has been developed in order to investigate periodic elements of unsteady flow fields. The technique synchronizes the phase of measurements taken at different locations using a reference signal and collapses the spectral peak of interest onto a single frequency. The technique has been applied to data gathered using a time-accurate 5-hole probe behind a two dimensional body exhibiting vortex shedding. It has been possible to generate a sequence of instantaneous pressure and velocity fields which show the shedding of vorticity and total pressure loss to form a vortex street.