bluuebunny/crossref_metadata_2025_split huggingface dataset:
Performance of Vehicle Engines on Heavily Leaded Fuels
Authors: Long R. W. 
Published: June 2010

Production problems on exhaust valves for vehicle engines, created as a result of the introduction of heavily leaded fuels during the 1939–45 war, resulted in the Ministry of Supply commencing research in 1948 to ensure that existing engines in civil and military vehicles would operate satisfactorily on a fuel containing 3.6 cu. cm. tetraethyl lead per Imperial gal. (T.E.L./I.G.) Road tests at the Fighting Vehicles Research and Development Establishment at Chertsey, Surrey, were planned to establish the form of initiation of valve failure, which, in almost every instance, was found to be due to the partial seizure of the valve in its guide through fouling by overheated products of combustion. All modifications were, therefore, directed towards reduction of exhaust valve and guide temperatures, and the dispersal of combustion products. Although fuels containing tetraethyl lead possess lead scavenging agents, nevertheless lead compounds form a large percentage of the deposits which accumulate on the surfaces of the combustion chamber and valves, and it is this increase in bulk, rather than the nature of the deposits, which appears to have the major effect on engine deterioration. Modifications on the various engines differed considerably. Coolant systems were modified wherever possible and valve design amended. Changes involving major components such as cylinder blocks and cylinder heads, although desirable, were inappropriate to the programme. Design features on new engines directed towards reducing operating temperatures where they were highest should ensure much longer exhaust valve life on heavily leaded fuels.
Aero-Engine Exhaust Valve Development
Authors: Morgan J. E. 
Published: June 2010

The chief problem affecting the exhaust valve is cooling, and most causes of failure emerge from it. For best results, therefore, development must extend to associated components such as guide, insert, etc., and all are surveyed in this paper. Development can be divided into three main channels: (1) heat transfer, (2) maintenance of gas seal, and (3) corrosion resistance. Improvements in heat transfer were obtained by the introduction of sodium cooling, firstly in the stem only and secondly in the stem and head. Further advantage was derived from improving the cooling of the seat insert of the exhaust port. The gas seal was improved by modifications to the insert. This was changed from Silcrome steel to Silcrome faced with Stellite, and finally to Nimonic 80. The latter material has good corrosion resistance qualities and yet is sufficiently ductile to be reformed by the valve when temperature gradients in the cylinder head have forced the insert shape out of round. The search for corrosion resistance led to the testing of a variety of hard-coating alloys and valves forged in Nimonic alloys. The latter were unsatisfactory when made up as solid-head valves but, more recently, a similar alloy has given good results with the hollow head and stem design. In this instance, however, a hard-coating alloy was used on the seat and combustion chamber face. Cylinder block life between overhaul is largely controlled by the performance of the exhaust valves, and whereas in 1947 block life at 400 hours was half that of the engine carcase, service testing has now shown that a block life of 1,250 hours is possible.
Exhaust Valve Life: Some Metallurgical and Mechanical Considerations
Authors: Mogford R. D. , Ball F. A. 
Published: June 2010

The factors controlling heat flow into and from the head of an exhaust valve are discussed for the purpose of indicating the means by which temperature, the overriding important factor in exhaust valve failure, can be reduced. This analysis suggests the lines along which the designer and the metallurgist must co-operate. The causes of exhaust valve failure are reviewed, and the conclusion is reached that the majority of these are the result of corrosion fatigue. Even for resistance to burning the two properties inherent in resistance to corrosion fatigue, namely resistance to corrosion and good hot strength, are essential. Laboratory tests for determining resistance to high temperature corrosion fatigue and hot hardness are described, and some results given for exhaust valve materials. Corrosion fatigue resistance is considered to be so significant a factor in exhaust valve failure that it is suggested that laboratory tests to determine this property should form the basis for the development of improved exhaust valve alloys.
Front Suspension and Tyre Wear
Authors: Gough V. E. , Shearer G. R. 
Published: June 2010

Tyre wear depends very largely on the cornering orces which tyres are called upon to develop. A consideration of the effects of front suspensions on tyre wear involves a discussion of the effects of suspension and steering geometry on the slip angles developed at the two front wheels. The paper explains why a tyre, developing a cornering force, wears, and shows that the rate of wear increases rapidly with increase of cornering force. It then proceeds to a brief history of types of suspension. The two types predominantly in use are examined for such effects as changes of alignment and of track, which can cause the tyres to operate under slip angle conditions. The location of the track rod and the rigidity of the steering linkage are shown to be of importance. Such trends in vehicle construction which have improved stability have tended to increase front tyre wear in relation to that of rear tyres. The paper attempts to deal with matters of principle rather than of practical detail of design and construction, but it is shown that quite small changes of practical detail can at times have significant effects on tyre slip angles, and hence tread wear.
Rubber Springs for Vehicle Suspension
Authors: Moulton A. E. , Turner P. W. 
Published: June 2010

The authors believe that rubber is especially suitable as a suspension medium because of its intrinsic properties, and also because of the variety of forms into which it can be made, and that it will therefore take its place alongside steel springs as an accepted vehicle suspension. A research programme of both field and laboratory testing has been carried out to confirm the suitability of rubber for suspension purposes, and to develop some modern forms of rubber springs. Laboratory work included, in addition to the fatigue testing of a wide diversity of spring types, the development of a method of strain measurement for springs of irregular shape, and the determination of a basic parameter of fatigue applicable to any type of rubber spring. Service testing included the investigation of endurance characteristics, optimum values for the static deflexion, damping and low temperature properties, permanent set and noise isolation. As a result the authors consider that their tests have demonstrated the practicability of rubber as an automotive suspension medium, and that it can afford a simplification of the design by providing wheel location, a measure of inherent damping, and so long as the design is studied from the beginning to include rubber suspension, competitive cost in volume production. Rising rate characteristics, a degree of noise isolation and satisfactory fatigue life are readily obtained.
A Review of Hydrokinetic Fluid Drives and Their Possibilities for the British Motor Industry
Authors: Giles J. G. 
Published: June 2010

The history of the development of hydrokinetic fluid transmissions is traced from its origin by Föttinger to the present time, and the important early developments and types of device are recorded. Consideration is given to special design features and current practice for the use of these devices in transmissions for motor vehicles, and the theoretical basis of design is reviewed briefly. Four important aspects of a specification for an automatic transmission for motor vehicles are enumerated, and the hydrokinetic fluid drive is shown to have characteristics specially suited to the fulfilment of this specification. The trend of development after the 1939–45 war of these drives in the United States of America is discussed, and appears to be reaching finality. The application of this American experience to European conditions is considered; some versions of the automatic fluid transmission show possibilities for achieving an acceptable operating performance for lower power/weight ratio applications. The wider range of torque conversion necessary for the more popular cars results in a more complicated and costly transmission, so that it does not yet appear likely that this form of automatic transmission will become universal in the British industry.
Transmission Developments for Public Service and Heavy Goods Vehicles
Authors: Wilson A. Gordon 
Published: June 2010

The author has set out to review the use, development, and history of the transmission system as applied to commercial vehicles and to forecast the future trends. The point is made that the transmission system is to be considered in relation to the vehicle and the service to which the vehicle is put rather than as an end in itself. The characteristics of the various systems at present available are therefore examined from the aspect of their effect on vehicle performance. Since engines of similar characteristics are fitted into an ever-increasing range of vehicles of divergent types, features of the various types of transmission are analysed to give a rough guide as to their suitability for differing service. For this purpose the modern types are grouped under a form of genealogical tree, in which an attempt is made to trace their ancestry. Commercial vehicle usage is broken down into type of vehicle, and the main markets into which they are sold and the various contradictory features exhibited by the behaviour of the transmission system in the vehicles are listed with a suggestion of preference for the type of vehicle in that particular market. Characteristics of different classes of vehicle are examined in relation to driver reaction, and the type of control which would be most likely to appeal to drivers accustomed to them. The Appendix gives diagrammatic drawings of transmission systems developed over the last half-century.
Some Important Problems Concerning the Small Utility Car
Authors: Giacosa D. 
Published: June 2010

This survey on the small utility car is based on the work performed under the supervision of the lecturer as Director of the Design and Engineering Division at S.p.A. Fiat in Italy. The lecture deals with the general principles relating to the design of a small utility car, mass-produced at the rate of at least 350 per day, particularly suitable for the Italian market, but also of technical and commercial interest to other European countries. Taking as his example a four-seater car having a weight ranging from 500 to 600 kg. (1,100 to 1,320 lb.) and with a total piston displacement of from 400 to 600 cc. (24 to 37 cu. in.), the lecturer analyses the most important factors that influence weight and therefore cost, such as general car architecture, dimensions, performance and quality. Some of the problems peculiar to rear-engine installation, which required a larger amount of studies and research during the design and layout work for the Fiat ‘600’ car are then examined. According to the lecturer, the rear-engined car represents the best solution both in regard to smaller outer dimensions required for given passenger accommodation, and as to constructional simplicity. The lecture is concluded with a forecast of future developments in this type of car.
Sealing Rings for Wet Cylinder Liners
Authors: Hepworth J. L. 
Published: June 2010

It is vital to the performance of an engine that sealing rings fitted to wet cylinder liners should effectively prevent the leakage of coolant into the crankcase, prevent lubricating oil entering the coolant circuit and at the same time avoid distortion of the cylinder liner. The sealing effect of the ring is due entirely to the pressure it exerts against the cylinder liner by virtue of its own elasticity. The effect of rubber hardness and compression upon wall pressure is investigated and proposals made for suitable standards. Design recommendations are proposed and a specification is laid down for material which will give satisfactory performance under arduous conditions.
The Supercharging of High-Speed Diesel Engines by Mechanically Driven Compressors
Authors: Millington B. W. 
Published: June 2010

The most useful application of the mechanically driven supercharger is in the field of the smaller Diesel engine which operates over a wide range of speed, and especially where the duty calls for a high torque to be developed at low speed. Road vehicles and earth-moving plant commonly require these characteristics. In the interest of fuel economy a high adiabatic efficiency is of first importance in a supercharger so used. It is also desirable to be able to control the rate of air delivery from the supercharger to match the load on the engine; methods are discussed and test figures from the Fell locomotive propulsion engines are quoted. Where a simple fixed ratio drive to the supercharger is used a good volumetric efficiency at low speed and at the working pressure ratio is important in order that the boost at low engine speeds shall be high. The Ricardo wobble-plate compressor designed to meet these conditions is described and performance data are given. Overall performance figures of an engine when supercharged by this compressor are also included and the methods of applying the engine in vehicle service are discussed.
The Turbo-Charging of High-Speed Diesel Engines, Present Position and Future Prospects
Authors: Bradbury C. H. 
Published: June 2010

Consideration is given to the basic principles of supercharging and the advantages and/or drawbacks of using surplus exhaust energy to drive the supercharger. A review is given of the application of the exhaust turbo-charger to high-speed engines of the road vehicle type. It is shown that there are now in existence units which can be mounted without adding appreciably to the overall bulk and weight of the engine, and which enable the latter to develop brake mean effective pressures of up to 140 lb. per sq. in. without undue smoke. Torque and acceleration characteristics are considered and limitations vis-à-vis positive displacement blowers are briefly surveyed. Lessons to be learnt from large engine practice are then reviewed, particularly from the standpoint of charge cooling. The Miller and Bone systems are briefly described. The trend of development towards higher pressure ratio turbo-chargers is then considered, together with the possibilities of incorporating in the engine design improved pistons and fuel-injection systems. The paper concludes with a brief reference to the present position and practice of turbo-charging two-cycle engines.
Tyre Tests and Interpretation of Experimental Data
Authors: Fonda Albert G. 
Published: June 2010

The test techniques and associated equipment developed for use of the Air Force-Cornell Tire Tester have permitted road tests yielding unique data on the cornering characteristics of pneumatic tyres. Account is given of tests performed for the Dunlop Tire and Rubber Corporation, involving variations of inflation pressure (18 to 45 lb. per sq. in.), camber (±30 deg.), and steer (±30 deg.); these angular ranges are unprecedented. The tyres were nominally 5.00, 6.00, and 7.00 by 16 section, of normal construction but smooth and round to eliminate effects deriving from tread pattern. The ensuing data analysis was based upon familiarity with aircraft derivative notation, the advantages of which are described, and upon simple tyre theory, which is outlined in an appendix. The outstanding conclusions, from a practical standpoint, are (1) that camber thrust strongly affects the static stability of the typical automobile; (2) that the motor cycle operates with negligible slip angle below 35-deg. tilt, whereas above 35-deg. tilt appreciable slip angle must be developed; (3) that a plot of pneumatic trail against side force has great value because of its linearity and ready significance; and (4) that tyre theory should be utilized to permit rational, concise interpretations of empirical data.
Design Implications of a General Theory of Automobile Stability and Control
Authors: Whitcomb David W. , Milliken William F. 
Published: June 2010

The lateral-directional motions of an automobile are studied by means of equations of motion derived for a vehicle assumed to have yawing and side-slip degrees of freedom only, and travelling at a constant forward speed. The equations are presented in terms of the automobile stability derivatives. The stability-derivative concept has its counterpart in aeroplane stability and control research. The automobile transient and steady-state motions following the application of steering control or externally applied side forces and yawing moments are determined from the equations of motion. The responses are discussed with emphasis placed upon their principal characteristics and the identification of the significant vehicle parameters that determine them. Approximate solutions for the steady-state response are also presented. The transient response characteristics are studied, first in terms of ‘single-degree-of-freedom’ approximations, and then in terms of the ‘two-degree-of-freedom’ representation. The transient motion is discussed in terms of the characteristics of a second-order dynamic system, and relations for natural frequency, damping ratio, and response time are derived. Conditions for system stability and oscillatory or non-oscillatory motion are also determined. The results of a series of sample calculations based on the equations of motion are in an appendix. These show the general character and magnitude of the responses of a representative passenger sedan and a high-performance sports car. The general characteristics of the transient and steady-state responses are summarized in chart form, and the influences of static margin, speed, and tyre and vehicle parameters are pointed out. A brief discussion of the desirability of certain response characteristics is presented as a generalized design objective.
Petrol Injection: Some Further Developments
Authors: Downing E. W. 
Published: June 2010

In this paper is described recent developments of a shuttle metering injection system, and details of the construction and operation of high-speed six- and eight-cylinder units are included. Accuracy in mixture control performance is stressed as an essential requirement of any injection system, and a description of a control giving automatic operation from cold starting and through the warm-up stages is given. An account is given of some aspects of the application of the system to a high performance six-cylinder engine, and includes details of air flow measuring technique, and manifold design and development for this class of engine. A description is included of the effect of mixture strength on fuel consumption and power output, where economy in the engine of a racing car is required, and combustion chamber and exhaust temperature variations with mixture strength are shown on graphs. It is concluded that on the engine referred to, injection can offer the advantage of an improved torque curve, or if needed, a worth-while gain of up to 10 per cent in economy over the carburettor at the same output.
Fatigue Testing of Vehicle Components
Authors: Stott T. C. F. 
Published: June 2010

By far the greater part of the vehicle manufacturer's testing programme is carried out on components or assemblies operating under similar conditions to those of specific requirements in service. Accelerated test procedures can produce in a few days results which would otherwise necessitate running many thousands of road miles. This method of testing has resulted in the development of specialized equipment together with the more versatile rigs which can be used for a multitude of purposes. To ensure true comparison and reproducibility of results, test procedures must be concise and based on service experience. Considerable attention must be given to failures which might either be reported from the field or occur during the normal course of the vehicle development so that a service background can be built up thus enabling ‘road miles’ to be closely related to ‘test cycles’. The fatigue testing of a number of components and assemblies is discussed together with the development of test procedures and testing methods. The parts covered are in the main those that are the more highly stressed and therefore more likely to be subject to fatigue failure.
Balancing of High-Speed Four-Stroke Engines
Authors: Clink R. 
Published: June 2010

The problem of balancing the rotating and reciprocating components of high-speed engines has engaged the attention of engineers for many years with the result that a considerable literature is now available on this subject. Generally, the need to minimize external and internal force and couple unbalance is well recognized, since only in this way is it possible to avoid excessive vibration of the engine and its surroundings as well as undesirable fluctuating loads on the engine and its mounting structure. Furthermore, an engine which is dynamically ‘quiet’ is generally more silent and durable than one which is not. Unbalanced rotating forces may be readily dealt with by the addition of counterweights to the crankshaft although extravagant use of these is to be avoided. Not only do they increase engine weight and cost, but the additional rotational inertia which they produce may lead to difficulties in dealing with the problem of torsional vibration. It is pointed out in the paper that where such weights are a necessity from the balance aspect, they may be designed as pendulum vibration absorbers so producing an engine which is smoother in a torsional sense. Unbalanced inertia forces are normally dealt with by selecting an engine assembly which provides collective balance of the forces at the individual cylinders, and in presenting this paper, the author considers that one of the best methods of studying these effects is by means of reverse rotation vectors. This method enables a clear picture to be obtained of the resultant unbalance effect of different engine arrangements and provides a ready means of determining the best solution. The representation of reciprocating forces by means of reverse rotation vectors is not new and, indeed, was the basis of the Lanchester second-order balancer for four-cylinder in-line engines. Some of the engine balancing arrangements in current use in the automobile industry are reviewed and discussed and mention is also made of some of the more important practical problems encountered when carrying out actual balancing operations on crankshafts and their associated components. Variations in the balance of identical engines may be traced to assembly tolerances and hence there is an increase in the practice of assembly balancing. As a logical conclusion it is to be expected that final balancing operations will eventually be made on the complete engine on the test bed.
Standards and Standardization in the Motor Industry
Authors: Woodbridge E. 
Published: June 2010

Reference is made to the I.A.E. standards, S.M.M.T. data sheets, ‘Big Six’ and ‘Heavy Five’ standards, S.A.E. standards, B.S.I., ISO, D.E.F., Company standards and the handbook published by the S.M.M. & T., ‘Standards for the British Automobile Industry’. Standards for purchasing, materials specifications, dimensional standards, production standards, and standard methods are also mentioned. Standards in relation to restrictive trade practices and the relationship between National and International organizations and Government regulations are included. It is stated that the adoption of standards should in most cases be voluntary and that use should be made of research in standards, for instance M.I.R.A. and R.R.L. and industrial research. Abbreviations used throughout are classified in an explanatory footnote†.