bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental Work on Exhaust Valve Life at Thornton Research Centre
Authors: Bedale P. W. , Graham R. 
Published: June 2010

Experience gained during the development of a bench test for assessing exhaust valve life has shown that the operating conditions of the engine are important in deciding not only the absolute valve life, but also the relative effect of fuel and lubricant combinations. It is concluded that short cuts in the estimation of exhaust valve life can give misleading results. The preparation of the engine for test and the test procedure are described, together with some details of the equipment used to observe the movement of the exhaust valves of a running engine. The stress gradient due to temperature variation across an exhaust valve head is estimated. The temperatures from which the estimate was made were obtained by measuring the hardness of a specially heat-treated valve after it had been in service. The shape of the temperature contours agreed with those found by others, and using published stress rupture data it was found that calculated valve life periods, based on the thermo mechanical stresses set up due to temperature variations, were of the same order as those found in practice
A Comparative Analysis of Various Methods of Engine Braking
Authors: Webb C. R. , Lavender J. G. 
Published: June 2010

The braking effect afforded by the engine of a road vehicle is normally regarded as a valuable addition to the wheel brakes. The degree of braking effort of an internal-combustion engine working on the overrun depends largely on how breathing is restricted, both at induction and exhaust. The paper clearly reveals the marked advantage of the compression-ignition engine compared with the conventional petrol engine so far as braking is concerned, largely on account of the difference in compression ratio. Out of the various methods of restricting the breathing, that of applying an ‘exhaust brake’ has a distinct advantage, particularly so in the case of a compression-ignition engine, where a resistance horsepower may be realized of about 85 per cent of the power output of the engine. An analysis of cylinder and manifold indicator diagrams taken from a multi-cylinder compression-ignition engine, using an exhaust brake, shows the interaction of the cylinder conditions, giving an advantage when a common manifold is used. It was concluded from the complete investigation that maximum braking effort is obtained with an exhaust brake operated with an unrestricted induction manifold. While the volume of air contained between the exhaust brake and the cylinders is required to be as small as possible, the interaction between the cylinders by using a common exhaust manifold increases the braking effect.
Transmission Wind-Up in Vehicles Having Several Driven Wheels
Authors: Steeds W. , Ellis J. R. , Thomson J. L. 
Published: June 2010

By wind-up is meant the twist that occurs in the transmission of a vehicle having several driven wheels but which is not provided with sufficient differentials to ensure equal distribution of the driving torque between the wheels, and which is due to inequalities in the effective rolling radii of the wheels. The first part of the paper discusses the importance of the wind-up phenomena and describes some experiments made on a rig in which wind-up could be developed and the wind-up torque be measured. The results show clearly that wind-up quickly reaches a steady state and that during this phase the effective rolling radii of the wheels change until they become equal. The second part of the paper describes some experiments, made on another rig, in which the effects of speed of rotation, radial load, inflation pressure, and torque transmitted on the effective rolling radius of a pneumatic tyre, could be determined. A selection of the results obtained is given in a series of graphs. The most important result is the establishment of the fact that the effective rolling radius of a tyre is a function of the torque transmitted by it and that if this function is known then the wind-up torque can be calculated. The paper concludes with a summary of the results obtained and some suggestions for ameliorating the harmful effects of wind-up.
Gudgeon-Pin Location
Authors: Cross R. C. 
Published: June 2010

The gudgeon-pin must be located relative to the piston so that it does not rub against or damage the cylinder. Many methods of location have been used but the circlip at each end of the pinhole in the piston and the pinch bolt on the connecting-rod small end are currently the two most popular designs. Another design which has met with much favour in the past is the use of a pad firmly fixed in each end of the pin. These pads are of suitable design and material so that, when they touch the cylinder bore, no damage is done. Some older designs included the fastening of the pin by a setscrew in the gudgeon-pin boss or by a washer on each end of the pin joined by a tie bolt. A pin can also be located by a piston ring on the centre line of the gudgeon-pin boss. First of all considerations is reliability, as failure of the locating means can cause very expensive damage. Cost and ease of assembly, light weight and simplicity are of importance. The pinch bolt is a sound design but is slightly heavier than the circlip location and the pinch bolt itself requires to be locked by tab washer or other means. Circlips must be correctly designed and made to prevent heat forming under working conditions.
An Approach to the Problem of Pressure Charging the Compression-Ignition Engine
Authors: Tryhorn D. W. 
Published: June 2010

It is shown from curves illustrating the effect of pressure ratio on charge density for various compressor adiabatic efficiencies that the efficiency of the pressure-charging system has a great influence on engine output. The Roots blower has been the accepted component for pressure charging for many years, but because of its low efficiency attractive engine outputs have not been obtainable. It is also very noisy and not easy to drive, so its use has been unpopular. To eliminate the shortcomings of the Roots machine the ‘Bicera’ compressor was designed, and the operation of this novel form of pressure charger is described. Test results are given which prove the performance to be superior to that of the Roots type, and when fitted to an engine showed that a pressure-charged four-cylinder engine can give the output of a six-cylinder, naturally aspirated engine, and can be as economical in fuel consumption.
General Introduction to a Programme of Dynamic Research
Authors: Milliken William F. , Whitcomb David W. 
Published: June 2010

This paper is a general introduction to a series of progress reports on an experimental and analytical investigation of the fixed-control directional characteristics of automobiles, and those mechanical properties of tyres used in the analysis of car stability and control. The programme under consideration utilizes aeronautical and control-theory techniques in deriving and substantiating equations of motion for the automobile. In addition, a six-component tyre-testing machine for static and dynamic tests on flat-road surfaces is described, and tyre data for a wide range of slip and camber angles are presented. In this initial paper an historical background of technological progress in automobile handling is given in a framework of vehicle handling in general, with particular reference to the science of aeroplane stability and control. This presentation enables a relative evaluation of automotive progress. The specific research objectives of the programme are then examined. A summary of dynamic concepts and methods is given in Appendix II. The paper also summarizes the results from the overall research programme, and concludes that the work has led to a better physical understanding of automobile behaviour, as well as to a mathematical model suitable for computing the fixed-control automobile motions. Significant comparisons are made between tyre data obtained in the programme and simple tyre theory.
A Device for Measuring Mechanical Characteristics of Tyres on the Road
Authors: Close William , Muzzey Clifford L. 
Published: June 2010

This paper describes a machine which measures the mechanical force and moment characteristics of pneumatic tyres moving over flat road surfaces. Development of interest in tyre force measurements is briefly reviewed, and the unique relationship of the Air Force-Cornell tyre tester to other tyre force-measuring equipment is indicated. The design evolution is discussed and the final configuration of mechanical, hydraulic, pneumatic, and electrical components is described in detail. The axle carrying the test tyre is supported at its ends by units which measure five forces. A sixth measurement, braking torque, is made simultaneously. These six measurements are used to compute total road reaction forces and moments, referred to any desired axes. The supporting mechanism permits the test tyre to be steered 30 deg. to either left or right, tilted (cambered) 30 deg. from the vertical to left or right, and vertically loaded with a force variable from zero to 3,000 lb. A braking torque of 13,000 in.-lb. can also be be applied. Electrical resistance strain gauges sense the forces and produce time histories on a recording oscillograph. The entire equipment is mounted on a 2 1/2-ton 6-wheel truck which can attain speeds up to 60 m.p.h. while testing tyres.
Suspension of Internal-Combustion Engines in Vehicles
Authors: Horovitz M. 
Published: June 2010

For a clear understanding of this problem a basic knowledge of theoretical aspects is essential. An analysis of the vibrating system is therefore given, together with the effects of out-of-balance and torque harmonics. Following a description of some forms of mounting unit, the author deals with incidental vibrations which are often caused by the flexibility of the vehicle structure. The elimination of these vibrations has been a major problem in recent years. Besides some orthodox designs described in detail, reference is made to a three-cylinder in-line, a three-cylinder opposed-piston engine mounting arrangement and the steel spring mountings used by an Italian car manufacturer. An appendix gives the formulae for calculating the various modes of vibrations and their frequencies. A further section shows the properties of two rubber sandwich mountings arranged in V-formation.
Corrosion Prevention in Automobile Bodies
Authors: Hoar T. P. 
Published: June 2010

The prevention of corrosion in car bodies has reached a high degree of excellence, or still leaves much to be desired, according to the point of view adopted. The organic finishing of the main part of car bodywork, utilizing heavy undercoats and durable top-coats on steel often prepared by phosphating, has reached a very satisfactory degree of excellence on flat or nearly flat surfaces. Difficulties still arise at edges, corners, crevices and re-entrants. These are discussed in relation to general principles of design and of testing. The finishing of trim is in a more fluid condition. Nickel/chromium plating of steel, zinc-base alloys and brass has long been the general bright finish adopted. The relative advantages and disadvantages of such trim and that made from bright anodized aluminium and from stainless steel are discussed. Newer finishes such as electrodeposited nickel-tin alloy coatings are also considered. Temporary corrosion prevention, such as can be applied to finished bodies for the period after manufacture but before service, is described. The contribution to corrosion prevention that can and should be made by the user is outlined. Storage methods vary widely, but are a very important factor in the life of a car. Cleaning and polishing methods are discussed. The general principles of corrosion testing appropriate to car bodies are considered, in the light of the very varied corrosive environments that are experienced in service.
Inspection of Vehicles for Road Worthiness, with Special Reference to Methods and Equipment
Authors: Grime G. , Lister R. D. 
Published: June 2010

An important section of the Road Traffic Act 1956 makes provision for the compulsory periodic inspection of road vehicles. In this paper are discussed some of the considerations involved, with special reference to the need for inspection, the items to be inspected, and the frequency of inspection. Descriptions are given of apparatus for measuring braking and lighting performance and, although for steering there is no commercial equipment with which a rapid assessment of the effects of wear and deterioration can be made, an experimental arrangement is described. Several other items which it is important to inspect can only be assessed in terms of individual judgement which may nevertheless give valuable results. The accuracy and consistency of an assessment made by means of test equipment is affected by variability due to uncontrolled factors and by the accuracy with which the various parts of the operation can be performed. The equipment has been examined from this standpoint and the results are given. Some of the facts which have to be considered in arriving at standards and test procedures are indicated and discussed.
Status of Automotive Petrol Injection in the United States of America
Authors: Gay Errol J. 
Published: June 2010

The author of this paper gives the present status of petrol injection in the United States of America and some of the problems which have been experienced in adopting the various systems to engines for passenger cars. Three vehicle manufacturers are currently offering petrol injection on option at extra cost. Not many systems have been sold, probably owing to the very high retail price of the various systems. A de-emphasis on horsepower has tended to reduce interest in fuel injection. Several American systems are shown and briefly described. The problem of reducing the cost of a system is discussed in terms of volume per day. Engineers are finding it difficult to match the performance of the carburettor. It has become necessary to provide ancillary equipment to the petrol injector so that carburettor performance is equal in regard to cold starting, warm-up and acceleration. Some systems have shown problems of high temperature operation. The author is of the opinion that there is a future for petrol injection. It may take three to five years before volume production is seen. Engines may have to be designed to take full advantage of petrol injection, with less emphasis being placed on power output and more emphasis on best fuel economy.
Influence of the Lubricating Oil on some Operating Problems of the Two-Stroke Gasoline Engine
Authors: Golothan D. W. 
Published: June 2010

The small two-stroke gasoline engine has recently become very popular owing to improvements in design and performance, and because of its general cheapness and simplicity of construction. Most of these engines are lubricated by the ‘Petroil’ system, that is, the oil and gasoline are mixed together before they are put into the fuel tank. This system, together with the characteristic design features of the engine, leads to various problems, the commonest of which are sparking plug fouling, exhaust port blocking, piston seizure, bearing corrosion, and general piston deposits. Various engine tests were used to study these problems, and it was found that their overall solution demanded conflicting properties of the lubricating oil. By a suitable compromise, however, it is possible to formulate an oil which gives satisfactory results in all aspects of performance.
Improving the Design and Performance of Road Tank Vehicles for Oil Marketing
Authors: Austin J. E. , Brear N. H. 
Published: June 2010

In this paper the authors have set out to show how changed concepts in the design and construction of bulk liquid carrying road vehicles can assist towards more efficient and economical transportation. Avenues for increasing tank truck efficiency are outlined, and consideration is given to some of the factors involved. An indication is provided of the kind of savings that could accrue from achieving a higher load factor and better average speed over the road. Comparison of these savings suggests that improved load factor should be given the greater emphasis. Possibilities for securing higher payload capacity and more effective vehicle layout by using newer materials and new techniques in construction are illustrated by reference to recent prototype vehicle development in the United Kingdom and Germany. Some details are given of strain-gauging undertaken on the prototypes to prove the tank design and to ascertain the feasibility of further structural refinements and weight-saving in this assembly. The need for a reorientation of thinking on chassis component weights as a further prerequisite for higher vehicle efficiency is emphasized, and future trends of development having component weight reduction as a major consideration are suggested.
Air Swirl in a Road-Vehicle Diesel Engine
Authors: Fitzgeorge D. , Allison J. L. 
Published: June 2010

The paper relates to the influence of port and piston shape on the dynamics of the air induced by a four-stroke oil engine of the type used for propulsion of commercial and passenger-carrying road vehicles. Consideration is given to the induction and compression strokes. A rig was constructed and used for the study of an existing design of port and for the development of new designs. The results of tests on the rig were used to estimate the performance of the various ports (on the basis of volumetric efficiency and swirl production) when used in an engine, as the rig tests did not directly supply this information. The squish process was also investigated by calculation, and the effects of variations in piston crown design considered.
Dynamics of a Four Wheeled Vehicle and the Effects of Suspension Geometry
Authors: Sethna P. R. 
Published: June 2010

An analysis of the dynamics of a four wheeled vehicle is made with a view to determining the design requirements that will eliminate sprung mass motions during acceleration, braking and on curves. No restriction is put on the values of the spring rates of the suspension system in this analysis and thus the results are valid for vehicles with very low suspension spring rates. The results of the analysis show that it is possible to eliminate sprung mass motions under these conditions: (1) if the four wheels move in certain prescribed paths with respect to the sprung mass; (2) if the braking and acceleration forces are distributed between the front and rear wheels in a prescribed ratio; (3) if the sprung mass distribution is such that it makes a certain product of inertia of this mass zero.
Factors Affecting the Performance of High-Speed Track Layers
Authors: Cleare G. V. 
Published: June 2010

The aim of the paper is to present some fundamental data from which the performance of high-speed track-laying vehicles can be estimated and on which preliminary design calculations can be based. The percentage of the gross engine horsepower that may be available at the driving sprocket is indicated and this must be equated to the resistance to motion that is likely to be encountered. Losses in the track and suspension system are discussed and reference is made to the effect of track tension. Some indication is given of the order of the horsepower required per ton of vehicle weight to achieve a unit of speed on various broad types of terrain. The effort required to climb gradients is also considered and it is shown that operation on cross-country terrain may be treated as an equivalent gradient resistance. Mention is made of the horsepower expended in steering a tracked vehicle and the manner in which the track forces have been found to decrease with increase in turning-circle radius. Since cross-country mobility also involves ability to cross water obstacles, some idea is given of the water resistance of the hulls of these ‘un-shipshape’ forms when afloat, and the overall efficiency that may be expected from the various means of propulsion that can be employed.
Possibilities for the Fuel Cell in the Passenger Car
Authors: Poulston B. V. , Kirtley J. G. 
Published: June 2010

The fuel cell is naturally attractive as a potential power source because of its direct production of electricity from fuel, quiet operation, and relatively high efficiency. Coupled with an electric traction motor, the fuel-cell battery may be a suitable power plant for passenger cars. This study indicates that with fuel cells having such outputs as are at present considered possible and with modern traction motors, fuel battery/electric cars could not match the performances of modern gasoline-engine cars unless they were very heavy. It is apparent that developments must continue in the direction of lightweight cells with higher outputs, lightweight traction motors, and possibly high-speed transmissions (including hydro-mechanical transmissions) if fuel battery/ electric cars are to become a practical possibility. These developments appear to be possible and could result in a fuel battery car with several advantages, including reduced fuel consumption. (The reduction could be appreciable if hydrocarbon fuels were used.) This appears to be the picture today, though further improvements to gasoline engines could whittle away the expected advantages of fuel cells.
Effect of Engine Structure on Noise of Diesel Engines
Authors: Priede T. , Austen A. E. W. , Grover E. C. 
Published: June 2010

The objectionable noise of a diesel engine or ‘diesel knock’ is produced by the abrupt rise of cylinder pressure resulting from initial inflammation of the injected fuel. Worth-while reductions of this noise have been achieved by the control of the fuel injection characteristics producing a smoother pressure rise, but these are limited by performance considerations. Further reductions can only be obtained by structural changes of the engine and these are considered here. This has led to the construction of a number of structure research engines using two basically different principles for controlling vibration of the outer surfaces, namely, control by damping and control by stiffness. In each case conventional cylinder heads, pistons, connecting rods and crankshafts are used but with different crankcase cylinder-block constructions. The first principle, employing control by damping, entails a skeleton load carrying structure arranged so that it exposes to the sides of the engine only narrow edges which do not radiate much noise because of their small exposed surface area. Highly damped panels, which cannot be set into resonant vibrations, are attached to this load carrying framework. Using the second principle, i.e. control by increased stiffness, an engine with a cast magnesium crankcase having a wall thickness of about 1 1/4 in was constructed. Magnesium was chosen so that the thickness of the crankcase walls could be increased to 5 or 6 times that of a normal cast-iron crankcase of the same weight. In subjective units these engines are about half as noisy as a normal engine using the same working parts. There are distinct differences in the characteristics of the noise of the two engines. The magnesium engine shows a tendency to be less noisy in the low and middle frequency range and is a little noisier from about 4000 c/s upwards.