Refine Your Search




Search Results


Technical Breakthroughs in Development of a Single Motor Full Hybrid System

Nissan has released our original HEV system in Japan on November 2010, and will release it in US market on March 2011. The 1 motor 2 clutch parallel type using conventional 7 speed automatic transmission has been employed without torque converter and with a manganese cathode and laminated type Li-ion Battery. This system is well recognized its higher efficiency but lower weight and cost, however, has never realized due to technical difficulties of smoothness. At this session, performance achievements and hinged breakthrough technologies will be presented. Presenter Tetsuya Takahashi, Nissan Motor Co., Ltd.

Global Market Developments

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

Powertrain Innovation Requires Infrastructure Innovation!

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

The deLavaud Automatic Transmission

MENTIONING the various attempts that have been made to secure continuous progressive changes of gear in the automobile, the author states that nothing of this sort is of value unless it is automatic. He has designed a transmission consisting of a wabble-plate which actuates six connecting-rods that operate as many roller clutches on the rear axle. Changes in speed result from varying the inclination of the wabble-plate, and this is controlled automatically through the combined effects of inertia and the reaction of resistance. This transmission has been applied to a number of cars of different weights, some of which have seen much service. The action of the various elements of the transmission is analyzed with the aid of drawings, diagrams and formulas, and the proportions that have been found most successful are stated. This transmission is combined with a gearless differential and a planetary reverse-gear.
Technical Paper

Future Clutch Progress Charted from Design A-B-C's

FIRST consideration is given by the author to basic improvements in clutches of the lever-release single-plate and to those of the two-plate types. He emphasizes that the severity of clutch service has increased very materially in the last few years and that the increased clutch duty of today is further augmented by the car manufacturer in providing cars having greater acceleration and higher torque, particularly at the higher speeds and usually without a proportionate increase in clutch size. Developments along logical lines which have resulted in improvements in design are cited as being (a) the design of the driven disc and the selection of facings, to produce improved engagement and greater life; (b) design of the cover-plate assembly to permit higher spring pressure with less retracting movement of the pressure plate; and better selection of facing and pressure-plate materials to reduce facing wear and pressure-plate distortion or scoring.
Technical Paper

Recent Progress Rapid in Design of Automatic Transmissions

THE TERM “automatic transmission” is defined as meaning an automatically shifting sliding-gear or sliding-dog-clutch transmission with certain fixed gear-trains, or any type of mechanism which will produce automatically an infinite number of ratios between engine speeds and driving-wheel speeds. Various types of drive are considered, as well as typical automatic gearshifts, emphasis being given to the operation of the Tyler transmission clutch and to the Mono-Drive transmission. Other subjects are the reactions of operators to automatic gearshifting and the future of automatic transmission. The desirable features of an automatic transmission are stated as being reliability; quiet operation; reasonable cost, weight, simplicity and efficiency; and correct functioning, which means that it must do the right thing at the right time.
Technical Paper


A brief description of the work required of the motorcoaches maintained by his company is given by the author, who states that the constant and ultimate aim of the department head who handles repairs and replacements is to keep down the cost per mile of operation. In compiling statistics of this cost, all charges against maintenance are divided into 30 distinct classes. As statements are made up, each item of the 30 classes can be compared directly with previous statements and a finger put directly on those items showing undue rise and serving to keep the total-cost-per-mile figure high. The author then describes certain special maintenance shortcuts and methods peculiar to the company's system which are followed in the three main service shops and greatly aid in retarding any advance in costs.
Technical Paper

Free-Wheeling Devices and Their Control

DEVOTED to the mechanism of free-wheeling devices, this paper contains detailed descriptions of the devices now in use on American cars and a résumé of the experiences of the Studebaker Corp., which pioneered the device in this Country, and other prominent manufacturers, showing how present designs of roller clutch have evolved from those first developed, in which several rollers of graduated sizes were used in each pocket. Lubrication of free-wheeling transmissions is discussed. Coil-spring clutches and one English design in which frictional contact is obtained through wedge-shaped shoes are also described. The author concludes with the suggestion of a combination unit to include free-wheeling, service brake and sprag.
Technical Paper


ONE-DIRECTION clutches have been applied to motor-cars to prevent the engine from being driven by the car when coasting and to facilitate gear-shifting. A number of representative designs are described in detail and in relation to their location in the transmission line. Following this is a detailed description of the construction and operation of the free-wheel device as applied to the Studebaker transmission, in which it takes the form of a single overrunning-clutch placed between the clutch gear and the splined shaft of the transmission in such a way that it serves to clutch either direct drive or second gear in either free-wheeling or positive engagement. Twelve rollers of graduated sizes are arranged in three groups in contact with three cam surfaces in the clutch. Sizes of rollers and dimensions of the cam surfaces are given. Tests were made for durability of the device, for savings in fuel and oil, and for any increase in demands on the brakes and generator.
Technical Paper


References to previous theoretical discussions of engine balance are cited prior to consideration of vibrations in four, six or eight-cylinder engines that may either be felt or heard in the car and result from lack of balance. Dynamic arrangement of the engine, unequal forces set up by the unequal weights of moving parts and vibration arising from elasticity or yielding of the parts themselves are the major causes of unbalance, of which the unequal weights of the parts are within the manufacturer's control. Unbalance of the conventional four-cylinder engine is of considerable magnitude, due to the angularity of the connecting-rod that produces unequal piston motion at the upper and lower parts of the stroke, the unbalanced force reversing itself twice per revolution and acting in a vertical direction. The actual magnitude of this force varies directly with the weight of the reciprocating masses and as the square of the speed.
Technical Paper


Remarking upon the progress made by the builders of machine-tools in providing equipment for locating and correcting the unbalance of rotating parts, the author divides into three major groups the units of a motor car that require particular attention and treatment to assure a smooth-running mechanism and gives details of the actual methods employed by the company he represents to balance the parts that constitute each group in the vehicles it produces. Representatives of the engineering and the manufacturing departments of this company studied the subject intensively and determined the types of balancing-machine and the methods to be employed, and special balancing equipment was devised also. Details of the balancing practice for crankshafts, flywheels, connecting-rods, clutches and propeller-shafts are presented and the subjects of impulse balance and the maintenance of balance for assemblies of parts are discussed.
Technical Paper


The magnitude of the business of the American Railway Express Co. requires that careful consideration be given to the details necessary for economical operation. The equipment comprises 12,755 vehicles, of which approximately one-third are motor-driven and have a carrying capacity of more than one-half the total. On July 1, 1918, when all the express companies were merged into one organization, it was found that the motor-vehicle equipment included 59 different makes and 131 different models. Among the 377 trucks built by one company were 21 different models. Diversity of equipment, of course, complicates the maintenance problem and adds to the cost. Additional expense is incurred frequently by purchasing and experimenting with parts offered by makers of accessories such as carbureters, spark-plugs, wheels and the like. Careful inspection, adequate lubrication and the adoption of “stitch-in-time” methods will save needless expense.
Technical Paper


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


Referring to the McKeen gasoline-driven car and one of the gasoline-electric type that were introduced in the early part of the present century and were the pioneers among self-propelled cars for railroad use, the author ascribes their limited success to their excessive weight and to engine and transmission troubles. Both these types, he thinks, might have been developed successfully had the gasoline engine been in its present state of efficiency and reliability. The early attempts having been more or less unsuccessful, the construction of all types was discontinued during the war. More recently the progress in the design and construction of highway motor-trucks has caused them to be adapted to railroad service by applying flanged tires to the rear wheels, pivotal pony-trucks forward and a motorbus body for the carrying of passengers and a limited amount of baggage.
Technical Paper


This paper contains a brief description of the Entz electric transmission. Wiring connections are given of the several speeds, for electric braking, for starting the engine and for charging the battery. The statement is made that the electric transmission eliminates and does the work of the friction clutch, the clutch pedal, the transmission gears, the flywheel and separate starting and lighting systems.
Technical Paper

The Constantinesco Torque-Converter

THE purpose of the mechanism described is to produce an instant and automatically variable torque that is always equal to the resistance encountered while the primary driving engine maintains its speed and torque nearly constant. The principle of operation is illustrated by reference to the action of a stick weighted with a ball at one end and suspended freely by a string at the other so that it can swing as a pendulum. Interference with the swing of the pendulum at any point on the stick results in a transference of part of the inertia force of the ball to other parts of the stick and also alters the amplitude and rate of vibration of all parts. At the same time, pressure is set up at the point of interference. The pressure varies in magnitude with the inertia and is proportional to the change of speed in a unit of time.
Technical Paper

The English Light-Car and Why

ECONOMIC and other conditions that favored and practically forced the development of the light car in England, and the history of that development, are dealt with at length by the author. He recalls the light cars of the pioneer days of the automobile and then the putting on of weight about 1898 to increase reliability and riding comfort. He comments on the reaction that resulted in the advent of the cyclecar in 1911 and its quick demise because of its failure to perform satisfactorily. The keen interest of the public, however, indicated that a big business could be done in a light, efficient, cheap motor-car if it could be produced in a practical form. Genuinely light cars minus the crudities of the cyclecar began making their appearance and quickly “caught on,” due to the tax on gasoline, low selling prices, and automobile-club competitions giving the public confidence in these vehicles.
Technical Paper

Timing-Gear Development

AFTER outlining the present status of the forms of drive for timing-gear trains, the author describes modifications of gear design made by the company he represents to overcome noise that involve lengthening gear-teeth for a given pitch. Various modifications in this regard were made and one having 16-pitch teeth with 12-pitch length had 10,000 miles of use in fourth speed without developing excessive wear. A further development resulting from experiments was the use of case-hardened timing-gears for motorcoach engines, such usage being thought to provide the most extreme conditions. Characteristics of so-called anti-stub gears are stated and predictions are made as to the future of timing-gear practice.
Technical Paper

Axle Ratios and Transmission Steps

STATING that improvements can be made in the smoothness, flexibility and economy of motor-cars by the provision of axle ratios and transmission steps that will make high road-speeds possible with lower engine-speeds than at present, and without increasing the size of the engine, the author presents arguments for the provision of two quiet and efficient gear-ratios. He asserts that the desired result can be obtained with either a two-speed rear-axle or a four-speed transmission having a quiet geared third speed, and a discussion is given of the considerations that determined the ratios actually selected in an experimental car fitted with a four-speed transmission having an internal-gear train for obtaining the third speed. Charts are included which show the car speeds at various engine-speeds and the grades that can be climbed with the several gear-ratios. The beginning of a tendency toward the use of transmissions of this type in Europe is reported at the conclusion of the paper.