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The primary purpose of this paper is to suggest basic crash sensor requirements which will form the basis for discussion of this subject. No attempt has been made in the body of this paper to suggest a particular crash sensor scheme or to recommend specific detectors or devices. However, an Appendix is provided in which is described the current General Motors sensor scheme. As air cushion systems are developed and evaluated, it becomes more apparent that the crash sensor is, perhaps, the most vital system component. In view of the criticality of this system component, a suggested comparative analysis of crash sensors has been included.

Several IORS crash sensors are compared with respect to operating principle, performance, and potential vehicular use. Desirable characteristics of the sensor mount are described. Forward mounted crash sensors are discussed as a means of providing early crash discrimination. Rough road and barrier test results with crash sensors are reviewed.

Inflatable occupant restraint systems (IORS) are categorized according to high, medium, and low momentum air bag deployment energies. Theoretical flow curves for these categories are presented which minimize deployment accelerations imparted to out-of-position occupants, in particular the standing child. Practical techniques to achieve these flow curves for stored gas, augmented gas, and solid inflators are presented. Aspirating systems are described, and their superiority over direct fill systems is indicated.

An anticipatory crash sensor for actuation of deployable passive restraint systems has been developed. The system consists of a 10 GHz continuous wave (CW) doppler radar. In operation, position discrimination is achieved through use of separate receiving and transmitting antennas, located on opposite sides of the front of the vehicle. An object is detected only when within the region of overlap of the two antenna patterns. Velocity discrimination has been achieved very simply in both digital and linear realizations. A threshold circuit permits adjustment of the minimum target size to which the sensor will respond. A variety of circuit and antenna configurations has been examined and constructed to obtain optimal system performance. These include hybrid systems which make use of mechanical confirmation of impact in an intermediate speed range, and more elaborate antenna configurations. Characteristics of typical targets have been determined experimentally.

Within the past several years many crash detector concepts have been evaluated for use in automobiles. The experience gained in the process of detector development has lead to several useful new design techniques. In this paper, under the general categories of design methods and design verification procedures, special applications of failure mode analysis, design perturbation analysis and inadvertent actuation prediction techniques are discussed. The design of rolamite acceleration-time detectors and the concept of fail safe and self-diagnostic design are presented as applications of specific methods.

A general discussion of crash sensor requirements is provided, with emphasis on the advantages of long inflation times. An explanation of the basic radar system is offered, and various designs, broken down both by antenna configuration and carrier modulation, are investigated. After careful study it is found that all radar sensors suffer from the same inadequacy-the inability to correctly classify obstacles into hazardous and nonhazardous categories. Several approaches to solving this problem are discussed. The conclusion is reached that radar crash sensors will be unavailable for MY 1976 air cushion requirements.

This paper describes a radar sensor which is being developed as an adequate sensor for an inflatable occupant restraint system. The important characteristic of this radar sensor is that an optimum highly sensitive sensing zone is formed by the combination of two transmission antennas and two reception antennas in order to improve the collision judgment accuracy, minimize the difference of precollision time for various obstacles, and suppress the received signal level due to rain and snow, etc.

Consumers' acceptance of and attitude toward a passive three-point belt system have been studied and evaluated in a personal interview investigation of 325 people. These participants were provided with the opportunity to try out the belt system in two demonstration cars-2-door and 4-door sedans. The method of selecting the respondents complied very well with the requirements of public representation. The results of the inquiry are presented in the full survey as related to driver, passenger, age, sex, etc. The main question in the study-the convenience when entering or leaving the demonstration car-was very positively judged. The most frequent opinion on a 7-point evaluation scale was as high as 7 (most positive); the average value of 6.2-5.9 was given for wide- and half-open doors, respectively.

Impositions placed on vehicle occupants by safety belts and safety belt use are substantial and will increase as systems to encourage or force belt usage are incorporated. By comparison, the known impositions of air bags are minor, but to these must be added other requirements, the extent of which are not yet well-known. Substantial fleet testing of air bags will clarify most of these inconveniences. Automobile manufacturers and the National Highway Traffic Safety Administration have failed to generate public support for the air bag. Lack of consumer support will continue unless greater resources are allocated to equip fleet vehicles with air bag systems so that a reliable record of air-bag efficacy can be compiled.

Crash sensor interfacing with the automobile must be approached from the occupant protection standpoint. Generation of the crash pulse, which determines occupant response, is affected by complex vehicle variables that often preclude discrimination from noncrash signals. Synthesis of the design solution is approached on a systems basis to match sensor capability to vehicle variables. Reliability is provided for with appropriate design of experiments and statistical analysis.

A mathematical simulation of the operation of a compressed-gas airbag system is developed. A system was built and tested, and the analysis is evaluated on the basis of these tests. Included in the study are nonideal gas effects, manifold and diffuser effects, bag stretch, bag leakage, and overpressurization of the passenger compartment. Interaction between a single rigid object and the bag is also considered. A correlation between bag pressure and the force it generates is obtained. This allows the development of an analytic model for determining the motion of a single rigid mass interacting with a dynamically inflating airbag mounted in a moving vehicle. An application of the model to study rebound of the occupant from the airbag is presented.

The air bag is ready and installation in front seat positions is essential at the earliest possible date. There has been almost a conspiracy of silence and a supression of favorable data-thus the media and through it the public are almost completely uninformed, or even worse, misinformed about air bags. An informed public will accept and should demand an air bag system. Minimal utilization of active restraints (lap and shoulder belts) mandates passive restraints (air bags). This group (S.A.E.) has a duty to cause a speed-up in the present rate of availability of air bags. The ultimate savings in lives and reduction in serious injuries as well as automobile insurance costs will be gratifying and substantial.

In this paper you will find problems posed by threatened lawsuits arising out of potential defects in passive restraint systems. For many years, it was recognized that the manufacturer of an automobile was liable for defects in manufacture or design which produce injuries. Now the question is should part of the cost of claims and verdicts be shifted to the government-this might make the government more responsive to the feasibility of adopting particular safety systems.

Lap-shoulder belts became standard with very little, very inneffective explanation of why they should be used. National effort is needed to persuade all to use them, and auto industry to improve them, and see the effect of buzzers and interlocks before mandating airbags or equivalent. This paper looks at the past history of restraints, forecasts the future if airbags are to be mandated without explaining them. AAA of Michigan motorist survey shows strong dislike of airbags, a preference for seatbelt-shoulder harness if choice must be made, a strong feeling that it is not the business of government to mandate airbag or seatbelt use. Question is raised about claims of number of lives that airbags will save. Are they too high?

Interest in fuel injection is spurred on by the promise of lower emissions. The problem of NOx will require better control of fuel metering to comply with the emission standards set by the federal government. Fuel injection and other basic engine changes can provide the emission levels by operating in a lean air/fuel (A/F) ratio to reduce NOx.

An External Combustion Engine (ECE) was designed, tested, and retrofitted to a 40 ft, 46-passenger city bus. The bus was tested and demonstrated comparable acceleration and lower external noise, odor, and air pollution emissions than a diesel bus. Presently, ECE bus fuel consumption is considerably higher than that of a diesel bus. It is shown in this paper how ECE fuel consumption can be improved with further development, although not to lower levels than the diesel. More time in service is needed to determine the ECE bus operating costs, which depend largely on the costs of powerplant maintenance.

The need for new mass transit vehicle alternatives has been spurred by the growing concern in our cities over photochemical smog, noise, smoke, odor, and transit system operating deficits, which are to a large degree the products of present rolling equipment. A project planned in conjunction with the San Francisco Municipal Railway is intended to demonstrate a practical kinetic energy (flywheel) propulsion system providing optimized electric transit with route flexibility and increased quality of service. The dual-mode trolley coaches used for the demonstration will be capable of providing scaled operational data that can be extrapolated to new classes of ecologically and socially acceptable vehicles.

In order to determine the operational characteristics of human pedal force, a driving simulator consisting of a driver's seat, pedals, analog computer, double gun synchroscope, etc., was developed. The driver was asked to guide the spot representing the controlled variable using the spot as a target. A simple transfer function to match the test results was derived and the effect of parameters on the constants in this function was analyzed. This experiment established that a pedal force of 200 daN seemed best for control.