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The scope of this recommended practice is to establish definitions and recommended methods for the measurement of lateral run-out and disc thickness variation in the laboratory and vehicle for passenger cars and light duty trucks up to 4546 kg gross vehicle weight. This recommended practice will breakdown the instrumentation (sensors and sizes), test setup, and data processing.

Develop a test methodology to measure the damping performance of a composite or other bar from the frequency response function obtained from the excitation force and the corresponding acceleration level, both measured at the same point.

The component level EPB actuation NVH task force should review existing specifications and measurement methods used in the industry to find any commonalities and propose a recommended method for measuring and evaluating component level EPB actuation NVH to be used as a common standard throughout the industry. The task force should acknowledge the following objectives: 1. Task force should review existing industry specifications and further define the scope for creating the new standalone component level EPB actuation NVH standard a. The common standard should be universally recognized and accepted by the automotive industry b. Provide confidence that acceptable vehicle related NVH results will be achieved if vehicle level testing is completed c. Provide clear verifiable acceptance criteria 2. Task force must lay out steps and timing to complete the development of the new common standard. 3.

The papers in this collection reflect the recent advances on the research, development and practices of Powertrain NVH treatment. The technical papers are of interest to powertrain system designers, testing specialists, NVH experts, and other individuals who evaluate and develop technologies to control powertrain NVH. The coverage includes: engine, engine subsystem and components noise and vibration; powertrain systems noise measurement and instrumentation; powertrain systems noise analysis.

“Spotlight on Design: Insight” features an in-depth look at the latest technology breakthroughs impacting mobility. Viewers are virtually taken to labs and research centers to learn how design engineers are enhancing product performance/reliability, reducing cost, improving quality, safety or environmental impact, and achieving regulatory compliance. Extreme environment sensors require extreme environment cables that can reliably perform in temperatures up to 2300° F, withstand intense vibration, and have extraordinary strength. In the episode “Sensors: Noise Avoidance and Cable Manufacturing” (8:53), an engineer at Meggitt Sensing Systems demonstrates the intricate process of developing cable for sensors used in these situations.

In this article the author presents analytical methods for determining the unbalanced inertia force and the tangential effort in a line engine. These methods are thought to be of interest for investigation of the effects of various engine design-features on its vibration characteristics. An equation for the resultant reciprocating force is set forth and methods of expressing the inertia and fluid-pressure torque are given. The determination of minimum and maximum resultants and the balance of inertia and fluid-pressure torques are other topics dealt with. The results of a series of analyses are incorporated in tabular form.

REFERENCES are given to many articles and books on crankshaft vibration, written in both English and German. As published experimental data on deflections are lacking, the authors obtained an engine with four crankshafts, having crank-arms with different cross-sections, and measured the deflections under static load. Deflections in various parts of the shafts are analyzed and compared, and a formula is developed for the deflection in the long crank-arms of the shaft.

THE primary purpose of this paper is to discuss some of the most pressing problems involved in choosing the propeller that is most suitable for use on a particular airplane. Propeller design is not dealt with, the discussion being limited to the selection of metal propellers of established design. Questions of noise, efficiency and diameter limitation are merely mentioned, and the emphasis is placed upon the choosing of propellers which will transmit the most engine power for the most needed condition of airplane performance; maximum and cruising speeds at altitude, or take-off and climb. Airplane performance enters only inasmuch as it is used to illustrate a case of power absorption. The proper choice of a propeller is becoming increasingly difficult to determine because of the current design trends of both airplanes and engines. Especially important is the fact that many of the supercharged engines now in use cannot be operated at full throttle below their critical altitudes.

THIS paper presents the solution of the factors in tires and wheels that cause a particular type of front-end vibration termed “tramp,” which is a vertical vibration of the front axle accompanied by a small degree of simultaneous oscillation of the wheel assembly about the king pin. This vibration in turn sets up the disturbance of the body and chassis. The front-axle vibration is caused by the unbalance and variation in rolling radius of the rotating front-wheel assemblies. The theoretical action of these two factors is developed in detail and supported by experimental results. The foregoing two factors act independently. The resultant of the two periodic forces which they set up depends on their phase relationship.

Irritated by statements of some alleged economists to the effect that, except for changes in the appearance of motor-cars, the automobile industry has stood still for the last five years, the author of this paper, who is affectionately regarded as the dean of automobile engineering in this Country, spoke at meetings of the Philadelphia and Metropolitan Sections of the Society on the many car and engine improvements made in recent years. Mr. Crane's remarks, as reported stenographically and embodied in this paper, deal chiefly with engines. He points out that extensive highway improvement and the consequent public demand for higher car speed have forced engineers to design more powerful and more versatile engines without increasing the weight. High-speed engines were of necessity the answer, and these brought the problem of eliminating roughness of operation and preventing transmission of vibration to the chassis.

GENERAL DESIGN and detail mechanical developments that have been made in the last year and incorporated in automobile, truck and motorcoach models for 1932 are reviewed by the author, who also points out noticeable trends in a number of directions. He deals in order with the cars as a whole and with each major component, from the powerplant to the tires and body, as found in many leading makes. Decision of the industry not to announce the details of new models until the end of the year, at or immediately before the opening of the New York Automobile Show in January, interfered with the presentation at this time of a complete picture of all the improvements made in American motor-vehicles, but enough information is believed to be given to show the more important developments and the ways in which the automotive engineers have responded to the desire of the times for greater refinement and efficiency in automobiles.

INSULATING of automobile bodies against noise and heat has been made more complicated by the trend toward lower and more compact bodies and larger and more powerful engines, as more noise and heat are created and must be excluded from the body. Development of the all-steel body also has presented a new problem that calls for different treatment than the composite steel and wood body. Elimination of noise and heat from the body is the mutual problem of the chassis and the body engineers and must be attacked jointly, correction of the trouble being made at the most logical and practical places. Much successful work has been done in the last few years to eliminate noise and heat, but much more can be accomplished by further concentrated effort. After listing the more objectionable chassis noises which have received most attention, the author considers the remaining noise and the heat against which the body must be insulated.

EARLY troubles experienced with torsional vibration in the shafting of marine and Diesel engines are mentioned, following which the various types of torsional-vibration damper are listed. Comments on the different ones are presented with particular reference to a damper with hydraulic coupling for a 3000-hp. 10-cylinder Diesel engine. The operation of this damper is described at some length, the text being supplemented by illustrations. Results of tests with this device are presented graphically, and the conclusion is drawn that the damping flywheel with hydrostatic coupling permits (a) damping of vibration of shafting even when running in the most dangerous speed-ranges of the largest engines and (b) running at all speeds without regard to vibration and without resorting to hand operation of the damping device.

Previous efforts to obtain comfortable riding-qualities for passenger-carrying automobiles are mentioned, and a device that combines a recording seismograph and a spring-action recorder is illustrated and described, since such a device is essential in conducting investigations of this character. Methods governing the use of the device when studying spring action and chassis vibration are outlined, and the results obtained are presented graphically and discussed. Several unique features characterize these tests and are worthy of consideration, not only because of the results obtained thereby but as being good illustrations of what can be accomplished by substituting unusual and perhaps spectacular methods in special instances for ordinary practice that has failed to produce some desired result.

Disc wheels are the answer to a demand for something better at a more reasonable price. The art of making wood wheels has been established, the machinery has become standardized and further reduction in cost is improbable; whereas the cost of suitable wood is steadily advancing and the trend, consequently, is upward. When the wire wheel was first introduced its use was a mark of distinction and to it can be traced the origin of the sport model, but its price cannot be reduced and it cannot compete, therefore, with the disc wheel on a price basis. The development of the disc wheel brought an equal distinctiveness of design and of pleasing appearance, but its progress has been different. The initial expenditure involved in the production of disc wheels is large; but the output also is large, and, as the volume increases, the prices become lower.

Annual Meeting and Detroit Section Paper - As the success or failure of the finish of an automobile depends largely on the finishing-varnish, a plea is made for more scientific analyses of the problems of automobile finishing and more care in selecting and applying a suitable varnish. The qualities to be desired in a finishing-varnish are divided into two classes: the shop qualities and the service qualities. The shop qualities include color, body or viscosity, working, flowing, setting, hardening, fullness and the safety of working. The service qualities, or those that enable the varnish to withstand the various conditions of use, include resistance to break-down under the chemical action of the actinic rays of sunlight, to the destructive action of moisture and the alkalis in mud and soap, to expansion and contraction, to vibration and to abrasion.

Smooth operation of motor cars becomes increasingly important as average driving-speeds become higher and as the public demands greater luxury and freedom from vibration. An analysis of vibration shows that it is caused by forces which can be calculated with considerable accuracy. Vibration itself is very complex, due to the inter-relation of forces, deflection and periodicity in the parts of the engine. In this paper a number of indicating and recording instruments devised for recording the actual resultant vibration and determining its exact character are described and their operation explained. Vibration due to unbalance of rotating parts, piston unbalance inherent in four-cylinder engines, bending of the crankshaft, centrifugal force, and torsional periods are discussed. Indicator-diagrams of the various kinds of vibration are shown. Unbalanced force and elastic reaction are the two general causes of vibration.

Although wheel wabble, even with high-pressure tires, is of ancient origin and the general methods of controlling it have been well understood, its importance among present-day problems is due to the fact that the recognized specific for its treatment, namely, increasing the air-pressure in the tires, has been denied. Shimmying, as generally applied, includes wabble, or the sidewise vibration of the front wheels about the knuckle-pin, and tramping, or the bouncing of the wheels vertically, alternately on the two sides. In addition to discussing the advantages and disadvantages of the low-pressure tire, the author has enumerated the results of tests, some of which have been obtained from original research work by himself, others from the literature on the subject, with a view to determining whether shimmying is caused by defects in design, and what are the effects when certain modifications are introduced.

The balloon tire has run the gauntlet of skepticism and credulity and has received scientific and popular approval from engineers and car-owners. The reasons for its acceptance are satisfactory appearance, practicability and transportation comfort. Tire and rim sizes, masquerading for years under wrong dimensional markings, have caused immeasurable inconvenience. This condition resulted from poor standards or entire lack of standards supervision. A committee with backbone is needed to fix and to maintain standards. Rapid balloon-tire tread-wear depends on tread profile, pressure and movement. Increased inflation-pressure and a scientifically designed tread will reduce the rapidity of this wear. Tread-contact areas and pressures are pictured to explain the advantages of a properly designed tread, and to demonstrate that the casing carries an appreciable part of the tire load.

General considerations that affect the attainment of adequate lighting are mentioned, it being stated that proper lighting of the interior of a motorbus is influenced by limitations peculiar to the service, such as vibration, scant headroom, a restricted energy supply and relatively large voltage-variations. Available types of bus-lighting equipment are analyzed as to their suitability, from six different standpoints that are stated. “Glare” is defined and means of obviating it are suggested, inclusive of a discussion of desirable types of finish for the interior with regard to reflecting surfaces. The severe vibration produced by many motorbuses demands head-lamps of more rugged construction than that used for the headlighting of private cars. Eight essentials for motorbus head-lamps are specified. A very large percentage of the glare and poor illumination of the motor vehicles on the roads results from improper adjustment or the lack of any means for adjustment of the head-lamps.