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In order to reduce wind noise, it is important to minimize the intensity of the noise source itself as well as to insulate the noise. The effect of body shapes on wind noise was investigated. The results are as follows: (1) Concerning wind noise, one of the fundamental causes is flow separation. The most critical areas are the windshield and the A-pillar. (2) A certain relationship between rain gutter height and side window recess depth produces the most wind noise. (3) Wind noise is suppressed if the airflow velocity is reduced around the A-pillar by an object such as the wind deflector.

Aerodynamic drag is one of the principal factors influencing fuel economy of passenger cars. Techniques are discussed which enable the effect of aerodynamic improvements to be evaluated utilizing computer simulation. Methods are also presented which enable such improvements to be realized. An acceptable drag coefficient of cD = 0.42 can be readily achieved within conventional styling concepts by refining and optimizing body details. “Detail Optimization” can enable gasoline (Diesel) powered vehicles to achieve maximum fuel economy improvements ranging between 4 % (5 %) and 7 % (9 %) above 1977 averages for subcompacts and full sized passenger cars respectively. Contemporary styling concepts placing great emphasis upon aerodynamics enable minimum drag coefficients of cD = 0.32 to be achieved. Application of such concepts and techniques can enable fuel economy improvements of 14 % (20 %) for full sized passenger cars and 11 % (14 %) for subcompacts to be realized.

This paper describes a BAseband Radar (BAR) sensor for radar braking application; an early version of the BAR concept was reported previously as a precollision sensor for air bag activation. In this paper we show how the normally wide effective beamwidth of the BAR is narrowed by using interferometry in conjunction with a novel delay line digital processor scheme. The beamwidth of the breadboard system spans a traffic lane width at 45 meters. The paper describes the details of the BAR sensor front-end and preliminary test results sponsored by the U.S. Department of Transportation and the Institute for Telecommunication Sciences.

We believe today that collision avoidance systems can appreciably reduce the number and seriousness of rear-end collisions. The mode of operation of a non - cooperative collision avoidance system is shown. Demands on the radar distance measurement system are described, e. g. questions of radar pulse mode, antenna diagram and choice of frequency. The decisive problem as regards evaluation of the radar echo is the reliable separation of desired and undesired signals. The presented technique uses a time magnification process followed by discrimination according to amplitude, pattern and echo jumps. In addition, there is a radar range limitation which is dependent on speed and steering angle. With experimental vehicles - equipped with the collision avoidance system - over 100 000 km have been covered. The results were very encouraging.

Generally in electric vehicles regenerative braking is incorporated to increase urban driving range on a single charge and to get the same brake torque as engine brake. In this paper analysis of the regenerative operation by thyristor chopper control is described. Firstly to clarify regenerative efficiency, the calculation of various losses such as commutation loss and thyristor loss which arises at braking mode is discussed, and it is described that the regenerative efficiency calculated from above losses agrees closely with test results. Secondly newly developed A.F.C. (Automatic Field Control) regenerative braking system is introduced. As in this A.F.C. regenerative control system, using shunt motor, field current is controlled inversely proportional to motor speed and regenerative operation is obtainable by low motor speed, this system is very suitable for electric vehicles.

The Electric and Hybrid Research, Development and Demonstration Act of 1976 required ERDA to develop data to determine the state-of-the-art of electric and hybrid vehicles. NASA, in response to ERDA's request, tested 18 electric vehicles. The U.S. Army's MERADCOM tested four electric vehicles and the Canadian Government tested one. Eleven of the electric vehicles were passenger cars and 12 were commercial vans. Tests were conducted in accordance with an ERDA test procedure which is based on the SAE J227a Test Procedure. Tests included range, acceleration, coast-down, and braking. The paper presents the results of the tests and comments on reliability.

Numerical models are described which simulate the wide-open throttle performance of vehicles equipped with either automatic or manual transmissions. Special consideration is given to the initial stages of the simulation including the buildup of engine speed and torque from the idle condition for automatic transmission vehicles and the clutch engagement process for manual transmission vehicles. Tire slip and wheel spin are treated by utilizing a semi-analytical tire model which relates tire slip to tractive force. Lateral weight shifts and effects of tractive effort on road load are also considered.

Multivariate least-squares regression techniques have been developed to screen, smooth and interpolate pollutant flows, fuel flow and other parameters of engine performance required for engine control strategy optimization. These methods have been applied to mapping data accumulated at constant speed and load, that is, regression has been performed as a function of air/fuel ratio, EGR and spark timing. In addition, the method has been extended to include engine RPM and torque as additional independent variables, allowing interpolation in the speed/load plane. Concurrently, procedures related to occupancy check for valid interpolation, determination of appropriate order of fit, data set overdetermination and graphical display have been devised. Examples of practical application of regression to engine mapping data are presented. The relative simplicity and accuracy of the regression method make it a valuable tool in the engine control optimization sequence.

Tests performed on three different configurations of hybrid vehicles establish that significant quantities of on-board petroleum fuel can be conserved by allowing the batteries to be discharged during the driving mission. The depleted batteries are then charged when the vehicle is not in use. Savings of as much as 50% of the on-board petroleum have been experienced with tests on the FDC. On SAE J227a, gasoline FE greater than 50 mpg was measured. Part of the energy for driving is thus transferred from on-board petroleum to off-board electricity generated from coal, hydro-electric or nuclear power plants, with no sacrifice in vehicle performance. The total energy used, when considering the replacement of energy to recharge the batteries, is analyzed. The results are favorable for the hybrid. A recommended new driving cycle for testing hybrids is discussed briefly.

Internal Combustion and Electric Buses have been in service world wide since 1913, and new circumstances and developments guarantee the expanding use of electrics on environmental, energy and economic grounds in the future. Present large Battery and Trolley Buses in Germany, Switzerland, Britain, Japan, North America and Australia are reviewed as to function, design and operational experience, and compared with diesel buses, trams and fixed rail city public transport. The Townobile Battery, Dual-mode and Trolley Systems can provide fixed rail system benefits at surface level, with much reduced capital and operating costs, and inherent flexibility to meet changing travel needs.

IN AUTOMOTIVE PACKAGING the utility of the design is of prime importance. The end product - the automobile - must not only be usable by all shapes and sizes of people, it must be so designed that it encourages correct use of its controls and devices. The driver should experience no obstructions, distractions or surprises in operating his car. The purpose of this paper is to show how computer methods can assist in solving problems of automotive packaging design in a 3D environment - prior to the construction of full-size mockups.

The characteristics of series and shunt d-c motors are reviewed, and the use of such motors as propulsion units in vehicular systems is discussed. Consideration is given to forward driving, reverse driving, forward regenerative braking, reverse regenerative braking, forward plugging, and reverse plugging. Both saturated and unsaturated modes of operation are described. Various types of controller for use in conjunction with d-c motors in vehicular propulsion are described also. Both electromechanical and electronic types are included. The relative merits of plugging and regenerative braking are then discussed.

The increasing importance of fuel economy causes cars to become smaller while passenger size requires certain minimum interior dimensions, especially to meet the requirements of passive safety. This has become an extreme challenge to automotive engineering. Providing the highest amount of interior space out of given weight limits while using conventional, cheap and easy to-handle materials stimulates new design philosophies. Various possibilities of increasing the passive safety of passenger cars by optimizing the structure and restraint systems while retaining the vehicle size, or, while maintaining the same degree of passenger protection, reducing the vehicle size will be described.

The human body has been increasing in size in many world-wide populations over at least the past century, according to documented reports. Such increases clearly have implications for the design of automotive equipment. This “secular increase” involves the body as a whole, applies to both men and women, and seems to affect the short-statured more than the tall. Summary estimates for this increase in stature have averaged around 1.0 cm per decade although there may be considerable variability between studies. The most likely explanations for this increase involve improved environmental conditions, specifically better nutrition, health care, and sanitation. Some groups currently show no secular increase in size. These include those who a) live in environments with less than adequate diets and medical care, or b) have already achieved their maximum body size potential as a result of living in optimal environments for growth. The secular increase in size is likely coming to an end.

A simulation of the exhaust emission testing system including a vehicle, dynamometer and driver on General Motors' analog-digital hybrid computer is described. The simulation predicts instantaneous and average results for hydrocarbons (HC), carbon monoxide (CO), oxides of nitrogen (NOx), carbon dioxide (CO2), and fuel economy over a predefined speed schedule such as the Environmental Protection Agency's (EPA's) city and highway schedules. The simulation facilitates the study of sensitivity of several parameters which influence emissions and fuel economy. The usefulness of the simulation to study the effect of test parameters, test operating conditions and product changes such as the engine, transmission, axle, etc., on emissions and fuel economy is outlined. Results from some of these sensitivity studies are also presented.

Serviceability has become a major design criteria at General Motors so that product standards parallel the rising level of consumer expectations. Eight areas of design consideration are explored: Replaceability, repairability, accessibility, diagnosability, maintainability, washability, towability, and liftability. This paper gives rationale for serviceability standards among auto manufacturers and suppliers alike.

With the fuel economy and emission requirements more demanding than ever and passenger-car engine control systems more sophisticated than ever, there exists a need for a methodical procedure to optimize the fuel economy subject to emission limits of the entire engine-vehicle-aftertreatment system over the federal fuel economy and emission tests. The optimal feedback control functions should account for: 1) transient system interactions; 2) cold start engine-catalytic converter warm-up dynamics; 3) exhaust aftertreatment; 4) driveability; and 5) any repeatable unknown phenomena which affect end-of-test fuel consumption or emissions. This paper presents an experimental Transient System Optimization (TSO) procedure which meets these requirements.

A cooling system design for a gasoline engine powered portable air compressor designed to meet EPA noise standards is evaluated. This paper covers the development that took place in order to devise an adequate cooling system for a silenced compressor with noise reduced by shrouding of the machine with a sound attenuating housing. The successful cooling system consisted of resolving maximum engine coolant temperature and maximum compressor discharge temperature while maintaining a compressor noise level of 76 dBA at 7 m. The cooling system design procedure involved is outlined. Noise evaluation at Sullair Corporation, and cooling system testing at McCord Corporation are reported.

A diesel-electric hybrid bus has been developed at the University of Florida. The drive system is a series hybrid with two lead-acid batteries and a diesel-driven three phase alternator. It was designed with the aid of a computer simulation program, and has undergone three evaluation phases since the initial construction phase. All results to date have confirmed the feasibility of the system including apparent significant advantages in the areas of exhaust emissions and fuel consumption.

Castor oscillations are of prime importance in many situations, from the simple tea-trolley to towed vehicles, the landing wheels of aircraft, and the motorcycle instability problem of ‘speed wobbles’. This paper sets out a mechanism of castor instability based on the lateral flexibility in the wheel support. In the case of a motorcycle this is the flexibility in the front fork/wheel system. For small amplitude oscillations the equations of motion are shown to be coupled ordinary differential equations which contain terms representing a relay switching function. These equations are solved numerically for many parameter variations. Close agreement is obtained with observed amplitudes and frequencies, and with the oscillation characteristics. For certain sets of parameters the numerical solutions are also found to agree well with the predicted solutions obtained using an analytic technique.