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Video

Performance of Particle Oxidation Catalyst and Particle Formation Studies with Sulphur Containing Fuels

2012-06-18
The aim of this paper is to analyse the quantitative impact of fuel sulphur content on particulate oxidation catalyst (POC) functionality, focusing on soot emission reduction and the ability to regenerate. Studies were conducted on fuels containing three different levels of sulphur, covering the range of 6 to 340 parts per million, for a light-duty application. The data presented in this paper provide further insights into the specific issues associated with usage of a POC with fuels of higher sulphur content. A 48-hour loading phase was performed for each fuel, during which filter smoke number, temperature and back-pressure were all observed to vary depending on the fuel sulphur level. The Fuel Sulphur Content (FSC) affected also soot particle size distributions (particle number and size) so that with FSC 6 ppm the soot particle concentration was lower than with FSC 65 and 340, both upstream and downstream of the POC.
Video

Vertical Picture-Frame Wing Jig Structure Design with an Eye to Foundation Loading

2012-03-14
The foundation of many production aircraft assembly facilities is a more dynamic and unpredictable quantity than we would sometimes care to admit. Any tooling structures constructed on these floors, no matter how thoroughly analyzed or well understood, are at the mercy of settling and shifting concrete, which can cause very lengthy and costly periodic re-certification and adjustment procedures. It is with this in mind, then, that we explore the design possibilities for one such structure to be built in Belfast, North Ireland for the assembly of the Shorts C-Series aircraft wings. We evaluate the peak floor pressure, weight, gravity deflection, drilling deflection, and thermal deflection of four promising structures and discover that carefully designed pivot points and tension members can offer significant benefits in some areas.
Video

Ionic Liquids as Novel Lubricants or Lubricant Additives

2012-05-10
For internal combustion engines and industrial machinery, it is well recognized that the most cost-effective way of reducing energy consumption and extending service life is through lubricant development. This presentation summarizes our recent R&D achievements on developing a new class of candidate lubricants or oil additives ionic liquids (ILs). Features of ILs making them attractive for lubrication include high thermal stability, low vapor pressure, non-flammability, and intrinsic high polarity. When used as neat lubricants, selected ILs demonstrated lower friction under elastohydrodynamic lubrication and less wear at boundary lubrication benchmarked against fully-formulated engine oils in our bench tests. More encouragingly, a group of non-corrosive, oil-miscible ILs has recently been developed and demonstrated multiple additive functionalities including anti-wear and friction modifier when blended into hydrocarbon base oils.
Video

A Methodology to Assess the Capabilities of a Cluster of Companies: The Case of "Torino Piemonte Aerospace"

2012-03-21
The increasing complexity of aerospace products and programs and the growing competitive pressure is facilitating the aggregation of small, medium and large enterprises of certain geographical regions into more integrated and collaborative entities (clusters). Clusters are by their same nature formed by heterogeneous companies, with huge differences not only in size but also for their core competences: such a diversity is a strength of the cluster, but it also increases its complexity. The purpose of this paper is to describe a benchmarking methodology that can be adopted to assess the performances of companies belonging to a cluster from different perspectives: economics and financials, competitive differentiators, specific know how, business strategies, production and logistic effectiveness, quality of core and supporting processes.
Technical Paper

A Generic Testbody for Low-Frequency Aeroacoustic Buffeting

2020-09-30
2020-01-1515
Raising demands towards lightweight design paired with a loss of originally predominant engine noise pose significant challenges for NVH engineers in the automotive industry. From an aeroacoustic point of view, low frequency buffeting ranks among the most frequently encountered issues. The phenomenon typically arises due to structural transmission of aerodynamic wall pressure fluctuations and/or, as indicated in this work, through rear vent excitation. A possible workflow to simulate structure-excited buffeting contains a strongly coupled vibro-acoustic model for structure and interior cavity excited by a spatial pressure distribution obtained from a CFD simulation. In the case of rear vent buffeting no validated workflow has been published yet. While approaches have been made to simulate the problem for a real-car geometry such attempts suffer from tremendous computation costs, meshing effort and lack of flexibility.
Technical Paper

Dynamic Behavior of In-Cylinder Pressure Causing Fatigue Failure of Reed Valves

2020-08-18
2020-28-0031
Numerous studies considering interaction between refrigerant and reed valve motion in positive displacement compressors have been cited in literature. CFD and FEA simulation tools have allowed modeling of fully coupled interaction of fluids and moving parts [1]. The present paper describes a simplified model of a multi-cylinder reciprocating piston compressor and estimation of pressure surge at high compressor speeds. The results show that the delayed discharge valve opening and closing causes surge in pressures due to formation of pressure waves. For the chosen geometry and operating conditions in the present paper, the characteristic travel time of such waves is much shorter (~ 0.2ms) as compared to longer response time of reed valves (> 1ms) owing to stiffness and exhibit delayed opening due to others factors too like stiction effect. These pressure surges may exceed the fatigue limit of reed valves and cause failures.
Technical Paper

Power Brakes for Passenger-Cars

1928-01-01
280017
THE use of a power medium in brake control points at once to the possibility of simplifying the brake system so that its characteristics, once established, can be expected to remain uniformly effective throughout extended periods without adjusting, with correspondingly long life of brake-linings. The author says also that, if the greater retarding effect possible with mechanically operated four-wheel brakes is to be fully realized, it is necessary to do one of three things: increase the pedal pressure, increase the brake leverage and consequently the pedal movement, or increase the “self-energizing” effect. The vacuum-type brake described is stated to be an amplifier which provides power to supplement muscular strength and assists the driver to apply the service brake, thereby reducing the required pedal stroke and pedal pressure without interfering with the regular service-brake hook-up.
Technical Paper

Automobile Induction-Systems and Air-Cleaners

1928-01-01
280051
AFTER indicating the trend of requirements in induction systems, the author discusses air-cleaners, carbureters and inlet manifolds. Particular attention is paid to improvements in centrifugal air-cleaners, that result in only slight pressure loss and in high cleaning efficiency. These improvements have been made by changing the body outline; by the addition of a diffuser, to make the resistance as small as possible; and by proportioning the vanes, as to angle and number, to increase the cleaning efficiency with only slight loss in pressure. Carbureters are considered briefly, only because of their interrelation with air-cleaners and manifolds. Inlet manifolding for four, six, and eight-cylinder-inline engines is studied, with variations in port arrangement. Recommendations are made as to the cross-sectional areas and form to secure best distribution of the mixture and adequate vaporization.
Technical Paper

Variable-Pitch Propellers

1929-01-01
290060
WHILE much experimental work has been done on the controllable-pitch propeller, complexity of existing devices has prevented their being placed on the market. After reviewing briefly the difficulties encountered, due to propeller and engine characteristics, the author discusses the effect of camber ratio and of angle of attack on the speed at which burble occurs, following this with comments on the efficiency of propellers as static-thrust producers, the use of the method of momentum to compute thrust and the application of adjustable-pitch propellers to supercharged engines. The causes of the forces required to operate the control adjustments are given as (a) friction, (b) twisting moments produced by centrifugal force and (c) twisting moments produced by air pressure.
Technical Paper

Manufacturing and Testing Rubber-Coated Automobile Fabrics

1927-01-01
270060
MORE than 13,000,000 yd. of rubber-coated top-material was produced in this Country in 1926, and, in addition, approximately 6,000,000 yd. of other types of material, including pyroxylin and oil-coated fabrics, was used for automobile tops. Principal ingredients entering into the manufacture of rubber-coated top and deck material are base fabrics, crude and reclaimed rubber, naphtha, sulphur, accelerators, antioxidants, inert fillers, softeners, and varnishes. Methods of manufacture are much like those used in the production of cellulose-nitrate or pyroxylin-coated fabrics, and the types of fabric used and their preparation are similar. Processes of preparing the rubber compound, applying it to the fabric, varnishing the surface and embossing the material are described briefly.
Technical Paper

Effect of a Centrifugal Supercharger on Fuel Vaporization

1929-01-01
290077
SUPPLEMENTING the results of an investigation at the Massachusetts Institute of Technology on supercharging a single-cylinder automobile engine which were presented at the 1928 Annual Meeting, this paper reports a study that was made to determine whether the mechanical action of a high-speed centrifugal supercharger improves engine performance by increasing the degree of atomization and vaporization of the fuel in the inlet manifold. While changes in the degree of fuel atomization and vaporization might be measured directly by sampling the gases as they pass to each cylinder, an indirect evaluation of these changes by measuring their effect on engine performance was considered more practicable. Tests were made on a six-cylinder automobile engine connected to an electric cradle-dynamometer.
Technical Paper

Combustion-Chamber Progress Correlated

1930-01-01
300005
PREVIOUS papers on Combustion-Chamber Design by three leading authorities on the subject showed enough points of real or apparent disagreement to leave the designing engineer in doubt on many of the details of design which they discussed. The author of this paper was asked to make a study of the works of these three authorities to discover points of agreement and clarify the subject for the benefit of engineers in general. Requests were made that each of the three authors in question furnish a list of his writings to be considered in this connection. Such lists were received from Mr. Ricardo and Mr. Janeway, but not from Mr. Whatmough in time for use in preparing the original paper. After the paper was delivered, a letter was received from Mr. Whatmough, and revisions in the paper have been made on the basis of that letter. Credit is given to Mr. Ricardo for initiating the study of combustion-chambers and inspiring other workers.
Technical Paper

High-Speed Oil-Engines

1930-01-01
300013
THIS paper, which was presented at meetings of the Buffalo and Pennsylvania Sections, begins with a statement of the advantages sought in adapting the Diesel cycle and developing oil engines to operate at high rotative speeds. Oil engines are classified according to their means for injecting and burning the fuel, and disadvantages attributed to the various systems are listed. Then follow descriptions of a number of engines of the different classes, selected according to the contribution their designs have made to the art. Particular attention is given to provisions for metering the fuel and for supercharging, which latter is said to have the same object as increasing the speed. Discussion* at the Buffalo meeting was on general problems of lubrication and fuel, on other methods for securing power from fuel oil, and on economic comparison of gasoline and oil engines.
Technical Paper

Diesel Engines for Automobiles

1930-01-01
300014
EXPERIENCE with a large sedan and a roadster in which the original eight-cylinder engine had been replaced by a four-cylinder Diesel engine is recounted in the first part of this paper, including road driving and establishing an official speed record of 80.389 m.p.h. at Daytona Beach, Fla. Then follows a description of the metering, injection and combustion processes of the Cummins engine, which are distinguished principally by the separation of the metering and injection operations so that the former is done at low pressure and the fuel is preheated and aerated before injection. Turbulence is caused and sooting of the injector orifices is prevented by the action of an air bottle in the piston-head. Discussion of this paper and H. D. Hill's paper on Small Diesel Engines will be found beginning on p. 290 of the September, 1930, issue of the S.A.E. JOURNAL.
Technical Paper

Vapor-Handling Capacity of Automobile Fuel Systems

1933-01-01
330014
THIS report covers information obtained on vapor lock, fuel-line temperatures and vapor-handling capacity as the result of road tests with 46 cars. The investigation was conducted under the auspices of the Cooperative Fuel Research Steering Committee in cooperation with the Natural Gasoline Association of America. The general procedure consisted in operating the car with samples of gasoline of increasing vapor pressure until vapor lock occurred. The development of a method for the evaluation of the vapor-handling capacity of fuel systems under various operating conditions has been of material assistance in analyzing the vapor-lock problem. The present work indicates that changes both in fuel-line temperatures and in vapor-handling capacity affect the permissible vapor pressures. It is still believed that lowering of fuel-line temperatures by changes in design of the fuel system is the most effective method of insuring freedom from vapor lock.
Technical Paper

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

1933-01-01
330011
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

Future for Low Pressure Tires Gradually Grows Brighter

1933-01-01
330008
DEFINITE change is occurring in the attitude of car engineers toward low pressure tires, Mr. Denham states. Asked whether even larger cross sections than those now proposed might improve riding qualities, “44 per cent of the engineers questioned said ‘No’; 22 per cent said ‘Perhaps’; and 34 per cent voted ‘Yes’. A year ago the vote would have been virtually 100 per cent in the negative.” Analyzing the reasons for this change in sentiment, Mr. Denham discusses the factors of appearance, riding qualities, traction, mileage steering, blow outs, and costs as related to the low pressure tire problem. He cites specific experiences recorded by individual companies and engineers during the past year and summarizes current engineering opinion on each phase of the problem.
Technical Paper

Correlation of Propeller and Engine Power with Supercharging

1933-01-01
330005
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.
Technical Paper

The Automotive Engine and Its Fuel

1932-01-01
320020
INCREASING realization by automotive engineers and by oil refiners that the nature of the fuel available largely determines engine-performance possibilities has resulted in valuable cooperative research, important progress and the preparation of a firm groundwork for future progress. The author outlines the more important characteristics that automotive-engine fuel should possess and indicates some of the relations existing between possible engine efficiency and fuel characteristics. Heat of combustion of a fuel, volatility, tendency to detonate and freedom from impurities are discussed. Actual data from two commercial cars for which optional cylinder-heads were available are presented.
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