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Powertrain NVH, 2017

2017-03-28
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.
Video

Spotlight on Design Insight: Sensors: Noise Avoidance and Cable Manufacturing

2015-05-07
“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.
Video

Global Market Developments

2012-05-16
The traction motor is key to the �synergy of the electric powertrain�, the overall functionality of the battery, e-motor, power control electronics, and charging system. Therefore some automakers have decided to design, develop, and produce their traction motors in house while some others are working with suppliers for their electric power train motors. Off-the-shelf motors, no matter how extensively they are adapted for a specific application, can compromise the efficiencies of the propulsion system. Presenter Marc Winterhoff, Roland Berger Strategy Consultants
Video

Powertrain Innovation Requires Infrastructure Innovation!

2012-04-10
Who are the people who know the most about the buses in your fleet? They are most likely the operators and the servicing technicians. They are also the key people whose knowledge, level of training and attitude can determine the success or failure of new powertrain technologies. Training and recruitment of both need to be held to a higher standard than we have seen in the past. I will argue that even the culture of those involved in fleet operations needs to be changed. The bar for technical competence and product knowledge needs to be raised for operators and technicians. In return managers should find ways to include them as stakeholders, investing them with both additional responsibility and accountability. This will require greater access to training and recognition of achievement. Where are the busses stored and serviced? Most likely in an all-purpose state/county/municipal service facility servicing a variety of equipment.
Technical Paper

Vibration in Automobile Engines

1928-01-01
280048
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.
Technical Paper

The Angular Distortion of Crankshafts

1928-01-01
280049
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.
Technical Paper

An Analysis of Tires and Wheels as Causes of “Tramp”

1933-01-01
330042
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.
Technical Paper

Airplane Vibrations and Flutter Controllable by Design

1933-01-01
330030
THE purpose of this paper is to pass on to airplane designers the things that have been learned in the last year about flutter and vibration of structures to which control surfaces are attached in order that, benefiting by all experience available, this great source of danger in new designs may be controlled. Test pilots also should be interested in this subject because it may help them in deciding proper action when a case of flutter is encountered and to recognize vibrations which may lead to destructive flutter. The present-day methods of stress analyses, imperfect though they are in certain respects, and the design load-factors in current use are adequate to provide all the strength needed in airplane structures for flight in rough air, and for all necessary maneuvers. A review of structural failures in the air reveals the fact that a resonant vibration was in nearly all cases responsible.
Technical Paper

HOW VERSATILE ENGINEERING MEETS PUBLIC DEMAND

1933-01-01
330032
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.
Technical Paper

Vibration of Instrument-Boards and Airplane Structures

1932-01-01
320010
THIS paper supplements one on the same subject by the same author, published in October, 1931, and describes a new and improved three-component vibrograph with which separate vibrograms of the three components can be obtained simultaneously and with considerable magnification. A short mathematical analysis is given to show the fundamental difference between vibrographs and accelerometers. Effects of vibration on different instruments are discussed and the approximate maximum permissible amplitude of vibration at cruising-speed frequency for various instruments is presented in a table. Consideration is given to correct design of instrument-boards and their suspension in an airplane, and the theory of forced vibration with damping is reviewed to show that, if not rightly chosen, shock-absorbing materials can do as much harm as good.
Technical Paper

Late Developments in Airplane Stress-Analysis Methods and Their Effect on Airplane Structures

1932-01-01
320011
RECENT developments disclose the existence of a well-defined tendency toward greater accuracy and thoroughness in airplane stress-analysis methods, which serve only as a link between applied loads and allowable loads. This trend has just begun. “Although we may justly look with pride on the aeronautical achievements thus far accomplished,” the author says, “our knowledge and ability are far from being complete or entirely satisfactory.” Hence, he analyzes several recurrent stress-analysis problems and indicates methods leading to their solution, because these seem to be outstanding in their ability to cause trouble for airplane designers. Better understanding is needed of the peculiarities of aircraft structure; such as lack of rigidity, the nature of inertia loads, the effects of flutter and of engine vibration, and the dangers of stress concentration.
Technical Paper

Noise and Heat Control in the Automobile Body

1932-01-01
320050
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.
Technical Paper

Practical Experiences with Devices for Damping Torsional Vibrations

1931-01-01
310006
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.
Technical Paper

A Study of Airplane and Instrument- Board Vibration

1931-01-01
310036
AIRPLANE vibration produces many undesirable conditions during flight, such as fatigue of structural members, a bad effect on the nervous systems of the occupants and the like. Excessive vibration leads to premature deterioration or to erroneous indications of instruments. Vibrations can be analyzed from a mathematical viewpoint with gratifying results, but such analysis is sometimes difficult and often is applicable only to selected conditions. A serious mathematical analysis was carried out in the investigation of resonance conditions between engine and engine mount. Then the problem was approached from a rather empirical viewpoint to give vibration relations, not, as heretofore, to bodily sensation, but to such terms as amplitude, frequency, the relation between the two, form and the like.
Technical Paper

SPRING-MOVEMENT AND VIBRATION STUDY OF CARS IN ACTION

1923-01-01
230042
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.
Technical Paper

AUTOMOBILE FINISHING-VARNISH

1923-01-01
230016
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.
Technical Paper

MEASUREMENT OF ENGINE VIBRATION PHENOMENA

1925-01-01
250005
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.
Technical Paper

FRONT-WHEEL SHIMMYING1

1925-01-01
250017
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.
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