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The general problem of ground simulation in wind tunnel testing of automobile models is reviewed. Detailed studies using a fixed and a moving belt ground plane are described and the influences of model bottom detail, cooling system air flow, and ground clearance are evaluated. The final evaluation compares wind tunnel model results with the full scale vehicle on the road.

The theory presented here allows forecasting of nitric oxide emissions in spark ignition engines. Following preliminary review of possibilities of obtaining the equilibrium state, as well as the basic concept of medium temperatures, the authors suggest using kinetic calculations for estimating the NO content of both unburned and burned mixtures. After good correlation is obtained, particularly for lean mixtures, the calculation is used to determine the best combustion process by simulation on a computer. Since experiments show an important effect of the fuel-air heterogeneity, complementary simulating work is conducted in order to define the best fuel stratification laws.

The combination of lean mixtures to provide oxygen in the exhaust and of exhaust heat conservation to enhance exhaust reactions yields significant exhaust reaction and lower hydrocarbon emissions. It requires adequately uniform mixtures, but does not require injection of additional air into the exhaust. A vehicle with this combination exhibits low emissions and good performance and fuel economy. Full evaluation of this approach must await general application. The results of this experimental exploration are presented as a contribution to the multi- industry effort to provide the public with acceptable atmospheric cleanliness at minimum vehicle and fuel cost.

The need for synthetic life testing as an aid to early decisions in new product design and development is discussed. Means of collating vehicle usage and operating regime data and the statistical determination of population parameters from a small number of test vehicles are shown and used as a basis for the formulation of synthetic life test schedules. Special-purpose and multienvironmental laboratory facilities designed to operate over a range of up-rated test levels are illustrated and the need is shown for obtaining correlation between the results of synthetic life testing and the predictions of service failure patterns obtained by road testing.

A sealed plastic enclosure was proposed in February 1967 by HEW as a technique for measurement of fuel system evaporative emissions from an automobile. Early work with this technique uncovered problems such as car background emissions. Subsequent experimental work, however, has solved these problems and has shown the sealed enclosure capable of correctly measuring total vehicle evaporative emissions. Fuel vapors that actually reach the atmosphere can be measured in a simple, direct way without the necessity for vehicle modification. A complete description of the enclosure is given and its use by GM is described.

The use of boron to increase the hardenability of steel (including low carbon steel) is an old concept widely used during the war years. Also it has been generally known that boron does not materially affect the hot or cold working properties of the steel. However, no one capitalized on these features to produce ductile high strength fasteners until U. S. Steel recently introduced a family of low carbon boron quench tempering steels. High strength fasteners and special parts produced from these steels offer such a fine combination of strength and ductility that they are, in most ways, superior to the highest strength fasteners and parts made from commonly used medium carbon alloy steels. In addition, the use of these steels will result in substantial manufacturing economies and broaden the possibilities for difficult cold forming of high strength heat treated parts.

The metallurgical effects of boron additions to carbon steel are reviewed. Mechanical property data for low carbon-boron steel fasteners is presented and is compared with similar properties for higher carbon steel fasteners. Mechanical property comparisons include data on tensile strength, ductility, toughness, fatigue strength and heat resistance. Mechanical properties of low carbon-boron steel fasteners are shown to be generally equivalent to mechanical properties of higher carbon steel fasteners with two notable exceptions: The ductility of the low carbon steel fasteners is higher than that of the higher carbon steel fasteners at all strength levels, and the heat resistance of the low carbon-boron steels is considerably lower than that of the higher carbon steels.

A complete gas turbine test and development facility was designed with sole reliance for steady state test work on a comprehensive, computer controlled, data acquisition system. The system was also designed to replace all standard instrumentation in six diesel engine dynamometer rooms. For the sake of those undertaking or considering this approach, the experiences of more than a year of operation are told to show the amount and kind of effort needed to make such a test service a practical reality.

The Dynamometer Laboratories of the Ford Motor Company installed a digital computer to automatically control tests; acquire, convert and store instrument data; monitor, alarm and initiate corrective action; and compute, and produce test results as punched cards, formated reports, and machine plotted graphs. The evolution of this application; the selection and implementation of a suitable system; the development of hardware and software features; and the technical and economic evaluation aspects are discussed. The system has been on-line since September, 1966, and has been performing engine and transmission tests under computer control. Examples of the resultant reports and graphs are presented.

This paper describes a study made to evaluate improved methods of collecting, recording, and reducing test data for increased test cell utilization in an engine test laboratory. The evaluation of five different approaches resulted in the selection of a process control digital computer system for direct data acquisition and closed loop control for engine test cells. This system provides better data, faster, and at a lower cost. A discussion is presented on the hardware, software, operating characteristics, and cost of the proposed system.

The development of a high speed, multichannel data acquisition system is described. A precision magnetic tape recorder is used to record analog data from highly transient phenomena. Analog-to-digital data conversion is performed on a hybrid computer and the digitized data is processed using large, high speed digital computers. A detailed example of the application of the system to the measurement of rates-of-injection, rates-of-heat release, and instantaneous rates-of-heat transfer from the cylinder gases to the cylinder walls in a high speed open-chamber diesel engine is presented.

The effects of physical factors on ignition delay have been studied on a motored research engine using a single injection technique. The fuels used included a high cetane number reference fuel, gas oil and M. T. 80 petrol. The primary factors investigated are those pertaining to the fuel spray, such as injection timing, quantity, and pressure (affecting drop size, velocity and injection rate); hole diameter (affecting drop size and injection rate) and spray form (nozzle type); and those pertaining to the engine, such as temperature, pressure and air velocity. Engine operating variables such as speed and load affect the ignition delay because they change the primary factors such as injection pressure, compression temperature, pressure and air velocity. It has been found that under normal running conditions, compression temperature and pressure are the major factors. All other factors have only secondary effects.

The unaided starting behaviour of seven diesel engines of different sizes and designs has been studied in some detail. It has been established that the cranking time required to achieve an ignition (the first fire) depends on (a) the compression temperature available for a given ambient temperature and cranking speed, (b) the increase in compression temperature per cycle when the engine is cranked and fuelled and (c) the temperature required for ignition which can be obtained from ignition delay data. The time taken from first fire to starter-off depends on a number of factors, and these are discussed and the differences in this respect between the direct injection (D.I.) and the indirect injection (I.D.I.) engines pointed out. Based on the above facts, the starting behaviours of the seven engines are shown to be predictable from the respective three sets of data described above and obtained experimentally.

Since the motor vehicle is controlled by the driver, dynamic consideration of the driver-vehicle system is necessary. In this sytem, eye sight is the most important sense with which the driver gets information from the course. In the present research, first, sighting distance in steady straight running was measured by the “slit method”. Next, sighting distance and sighting angle in various curvilinear runnings were measured by use of a “sight point camera” devised by the authors. Introducing the conception of sighting distance and sighting angle, dynamics of the driver-vehicle system is contrived. Theoretical calculation showed that sighting distance should be longer than a certain critical value to make the system stable.

The effect of pillar size on vision obscuration in the forward field of view is discussed. The SAE J941a Eyellipse has become an accepted design tool and is one of the first of its kind to be used in automotive driver work space design. A review of this recommended practice will include a brief reminder of its value and also of its limitations. An expansion of the tools limitations covering a driver head turned consideration is included. A review of a study in process for developing an Eyellipse for use in truck packaging is also included.

A new method, which enlists the aid of a digital computer, has been perfected to quickly and accurately determine the performance of a proposed rearview mirror while still early in the design stage. Because of the Federal Motor Vehicle Safety Standards (FMVSS) require a minimum viewing performance for both inside and outside left rearview mirrors, and since a common method — by which an intended design can be judged for compliance — would benefit both the Industry and the Federal Government, this method and the appropriate computer programs are being made available to all interested groups. Use of the computer programs results in a tremendous time savings over any manual drafting technique. This paper is intended to serve as a design guide to be followed when packaging rearview mirrors. A general introduction on the subject of rear viewing is followed by a discussion of the approach to the problem of evaluating the performance of a rear viewing device.

To the average truck or bus driver the critical problem of the “blind spot” has existed ever since flat mirrors were first applied to vehicles. With large vehicles and the single plane mirror it is entirely possible for a car to be hidden under the driver’s lower line of vision. This problem of “blind spot” is compounded, depending on the size of the vehicle, driver’s eye level above the ground, and the distance and position of his eyes from the mirrors. The mathematically designed mirrors discussed in this paper permit the driver to utilize the upper flat mirror for rearward vision; the reflected view of the blind area is in the bottom prepositioned mirror. It is believed that the next area of optics improvement will be with the noncommercial driver.

Wide variations in exhaust hydrocarbon concentration have been traced to the angular position of the top compression ring gap. Furthermore, with a fixed gap position, equally large changes in exhaust hydrocarbon concentration have been correlated with blowby flow rate, which was chiefly determined by the smallest of the two compression ring gap areas. Enlarging gap area increases blowby volume, which lowers exhaust hydrocarbon output. It is believed that the air-fuel mixture in the piston-bore-ring crevices escapes combustion and that both gap location and blowby flow influence the amount of this hydrocarbon-laden gas which makes its way into the exhaust gas. A modification of the piston and top ring, called the sealed ring-orifice design, has demonstrated the technical feasibility of reducing exhaust hydrocarbon concentrations by minimizing the crevice effect, while cutting blowby flow below that possible with production rings.

The Volvo Exhaust Emission Control System is an engine modification system employing the dual manifold principle, lean mixtures, idle spark retard, deceleration bypass valves, and increased idle speed. The design and performance of the system are described, including the influence on the Federal cycle results of various factors such as idle speed and idle mixture adjustment. Fuel economy, octane requirement, etc, is also discussed. Results of durability test are reported.

Requirements of federal and state agencies to control the exhaust emissions of motor vehicles defined performance standards for 1968. Consideration of economics and practicality motivated a full scale design and development program to meet this required performance without the use of a secondary control system. An analysis of new low quench type combustion chambers compared with the standard chambers used on two displacements of a 6-cylinder engine family in prior model years is presented in terms of parameters related to exhaust emission and to conventional engine design. The engine induction system, with special emphasis on carburetor characteristics, is contrasted for application to non-emission controlled engines with application to emission controlled engines.