bluuebunny/crossref_metadata_2025_split huggingface dataset:
Contribution to the Study of Deterioration in Automobile Engine Cams and Tappets
Authors: Cazaud R. , Renout M. , Daubertes C. 
Published: June 2010

During the last few years the cam-tappet problem has become very important because of the continuous increase in the maximum rotational speed of engines for the purpose of increasing power. This necessitates the overloading of the springs in order to offset the inertia effects of the distribution system as a whole; the result of this is to increase the specific pressures of the cam-tappet unit. As the present tendency is to make engines revolve at ever greater speed, it is to be expected that the problem of the behaviour of these components in service will be more and more difficult to solve. There is no doubt that the ideal solution lies in decreasing the inertia forces by giving up the rocker system, and using the arrangement of the overhead camshaft acting directly on the valve stem. For engines with the traditional system of valve action by rockers, the problem of the deterioration of cams and tappets has been studied by Simca on a specially designed testing machine. The laboratory tests thus made have been followed by tests carried out by the Shell Company on engines on the test bench. The present paper sums up the results obtained.
Second Paper: Catalytic Purification of Car Exhausts
Authors: De Rycke D. 
Published: June 2010

So far no less than 150 chemical components have been isolated in car exhaust gases and may be grouped as follows: (1) Oxides of carbon; (2) Unburned fuel; (3) Oxides of nitrogen; (4) Oxides of sulphur; (5) Lower hydrocarbons. Smog formation is a complex photochemical reaction, and this has been reproduced in the laboratory. The catalyst device attempts to complete combustion by initiating and maintaining a medium temperature zone which, with additional air but no more fuel, will convert hydrocarbons and carbon monoxide into carbon dioxide and water. The composition of petroleum must be considered in relation to other factors. Tests with cars have shown operating problems, and results are given in the paper. Research continues on this complex problem, and development of the catalyst is well advanced.
Tyre and Vehicle Vibration
Authors: Barson C. W. , Gough V. E. , Hutchinson J. C. , James D. H. 
Published: June 2010

An installation specifically designed for the measurement and analysis of vibrations generated at the tyre to road contact, of vibration through tyre, vehicle suspension and body structure is described. Results of tests on rolling drums, including tests on drums with special test surfaces and tests on hydraulic and electromagnetic vibrators designed to feed vibrations into the tyre at ground contact are given. As the hydraulic vibrator is capable of vibrations in the three directions, vertical, longitudinal and lateral, examples of the attenuation during transmission through tyre and suspension are given. Road test recording equipment is available and it uses the analysis equipment installed for the laboratory installation of vibrators and drums: elimination of long delays in analysis is given attention.
First Paper: Tyre to Wet Road Friction at High Speeds
Authors: Allbert B. J. , Walker J. C. 
Published: June 2010

The general problem of loss of tyre grip on wet road surfaces is discussed. The initial section of the paper covers a description of the testing techniques employed for the investigations reported. These include both road and indoor rig techniques developed to study limiting tyre braking and cornering properties under a wide range of operating conditions. The level of friction between a tyre and a wet road is primarily related to the ability to remove a water film from the ground contact area. The contact area is considered to be separated into three effective zones. Initially the ‘bulk’ of the film is displaced leaving a thin residual film to be penetrated at, or absorbed from, the interface before substantially dry contact can be established. The size of this dry area, at the rear of the contact zone, has an overriding control on the level of available friction and is dependent upon the time occupied in displacing the water film in the frontal zones. An increase in the peripheral speed of the tyre reduces the time available for water displacement and effectively shortens the area of actual ground contact. In the limiting condition the vertical load on the tyre becomes entirely supported on the water film and the condition of aquaplaning exists. The requirements for this condition to occur are briefly discussed. Tread pattern and road surface design are shown to exert a considerable influence upon the rate of water displacement from the contact area and hence upon the relative sizes of the water-supported zones. The forces developed in the dry zone at the rear of the ground contact are dependent upon the frictional characteristics of the tread material. A section of the paper considers the wide scale effects of tread pattern, tread material and road surface characteristics and discusses the nature of the interactions between these three variables. Some results of recent studies related to different types of tread pattern, specific pattern design features and the effect of tyre casing construction are included. Future potential development of the tyre contribution is reviewed.
An Abrasion Test for Use in Agricultural Engineering
Authors: Davies G. R. 
Published: June 2010

An abrasion test has been developed and used to compare the resistance to abrasion of a range of plastics and metals. The test is primarily intended for use in agricultural engineering and has been designed to cover a wide range of conditions such as occur in this industry. One of the main features of the test where it differs from most others is that it uses loose, and not bonded, abrasives. The results obtained so far, on about fifty plastics and metals, emphasize the importance of the resilience of the material in reducing abrasive wear. They also show that the resilience, or, more specifically, the vibration characteristics, of the support for the specimen, can. affect the rate of abrasion. Plastics test specimens appear to wear into two distinct final shapes and this shape seems to depend on both the material and the test conditions; it could possibly result from the two forms of abrasive wear already described in the literature. The possibilities of further work are discussed.
Characteristics of New Ignition Systems to Improve Engine Performance
Authors: Teasel By R. C. , Miller R. D. 
Published: June 2010

The increasing use of spark ignition engines throughout the world has confronted the engine designer with new problems such as air pollution, world-wide temperature extremes, as well as legislative, economic, and human considerations. To meet these situations and improve the competitive position of the spark ignition engine requires considerable research and development effort. This paper reports on work conducted by Champion Spark Plug Company in attempting to evaluate the potential contribution that ignition system and spark plug designs can make towards improving spark ignition engine operation. Almost all the work reported here covers investigations in current large displacement United States passenger car engines. The three main characteristics of the overall ignition systems that are investigated are (1) the available output voltage characteristics of the ignition systems; (2) the effect of the ignition system spark discharge characteristics on engine performance; and (3) the effect of several spark plug design features on engine performance. This investigation shows that the inter-relationship of the ignition system spark discharge characteristics and the spark plug design requires that the overall evaluation must consider the dependence of both items. It also suggests that significant improvements can result in other United States and European engines, through the careful evaluation of ignition system and spark plug designs. The results of this work indicate that a fast rise time, short arc duration system results in reduced spark plug gap growth and better resistance to spark plug fouling. However, the arc duration must not be shorter than a minimum value, or a loss in engine performance may result. High output systems are desirable as they provide a higher voltage reserve to provide longer spark plug life, but the higher voltages that occur with the larger spark plug gaps can stress other ignition system components. The spark plug designs which incorporate a projection of the spark plug gap result in better performance in the engines tested, and possibly even reduce exhaust emissions. Certainly other features which engine manufacturers must consider, which are not discussed in detail here, are costs, durability, and maintenance of the new systems. At least one other important related problem is that of interference.
First Paper: Some Considerations on Detecting and Preventing Spark Knock in the Car Engine
Authors: Addicott J. L. 
Published: June 2010

Spark knock is defined. Reasons are advanced for the continuing need to prevent knock but the claim that loss of power and engine damage will necessarily occur when operating at low engine speeds under knocking conditions is challenged. An outline is given of the types of gasolines that are available on the market for the car engine. The necessity to have available in engine development work reference fuels which broadly represent the possible alternatives that will be met in the market is shown. Suggestions are advanced for suitable reference fuels. Test bed, road and vehicle dynamometer work for engine development related to gasoline knock is discussed. The effects of engine component temperatures, of carbon deposits and distributor drive lash is given. The use of octane requirement survey data to the designer is shown. The importance of the minimum advance for best torque curve, the choice of an ignition advance curve and recommended ignition settings related to knock-free performance are discussed. The place for aural methods and instruments for the detection of knock is given.
Third Paper: The Influence of Engine Design on Spark Knock at High Speeds
Authors: Perrett J. B. 
Published: June 2010

Modern motor roads permit cars to be driven at high speeds for many miles. In these circumstances it is possible for engines to be operating in a condition of spark knock for a considerable time. Such knock might not be detected by the driver, but could initiate a chain of events leading to damage to the engine. A realistic procedure has been devised for carrying out tests for spark knock at high speeds, employing cars mounted on vehicle dynamometers. Tests on 30 European car models, all having manual transmissions, led to the critical knock speed concept for making comparisons between the high speed knock susceptibilities of various designs of engine. These comparisons have shown that, in service, over-advanced spark timing is frequently the prime reason for the occurrence of high speed knock. With spark timing set at the minimum advance required for the engine to develop its best torque, octane requirement is influenced by compression ratio, brake horsepower per litre, cylinder swept volume and disposition of the exhaust valves. Also to a small extent, by combustion chamber design and the amount of induction heating employed. Given attention to the above factors, it is felt that the high speed anti-knock requirements of the present generation of engines can be met by currently marketed gasolines of 98/99 Research octane number (ON).
The Relationship between Gasoline Composition and Spark Knock at High Engine Speeds
Authors: Grevett By S. P. , Tharby R. D. 
Published: June 2010

Since spark knock at high engine speeds is becoming an increasing problem with modern Western European cars, the relationship between this phenomenon and gasoline composition has been investigated. The engines prone to high speed knock are generally those of relatively high specific output (high bhp/litre) compared to the general car population. In such engines, spark knock at high speeds was found to be more closely related to Research ON and olefin content than to either Research ON and sensitivity or Motor ON alone.
Second Paper: The Design of Ambulances
Authors: London P. S. 
Published: June 2010

Although only about 5 per cent of the work of ambulance services concerns emergency cases, it is the seriously ill or injured patients that pose the most difficult problems in design. Much of this difficulty springs from the fact that only a few hundred ambulances are required each year, which means that vehicles produced as a result of special research and design would be very expensive. The following objectives should be accepted. (1) To eliminate jolts without causing nauseating swaying. (2) To provide a vehicle in which a stretcher trolley can be firmly fixed either in the centre of the vehicle or along each side, where trolleys could, if necessary, be used as seats. (3) To provide the stowage space for necessary medical and some light rescue equipment. (4) Easy entry for stretcher trolleys at the rear and easy passage between the crew and patient compartments. (5) Ideally, the suspension should be appropriate for a load of two crew, two stretcher patients and necessary equipment but in many cases economic considerations make it desirable to design ambulances that can carry up to ten seated persons. The only justification that a surgeon with very little mechanical knowledge can have for addressing this Institution on the subject of the design of ambulances is an interest in the subject born of the awareness of its importance, combined with detailed knowledge of what facilities seriously ill or seriously injured persons need while being taken to hospital.
First Paper: Emission Control by Exhaust Manifold Reactor—An Initial Study for Small Engines
Authors: Lawrence G. 
Published: June 2010

This paper describes the experience gained in a first exercise to investigate the potential ability of exhaust thermal reactors to reduce specific exhaust pollutants from European sized engines below the control levels likely to be legislated in the longer term. It concludes that such systems are both efficient and viable, subject to adequate development, and may become essential if the political trends towards increasingly stringent depollution standards continue.
Paper 1: The B.M.C. ‘A’ Series Engine
Authors: Appleby W. V. 
Published: June 2010

This engine was first introduced in 800 cm3 form in 1952, and the paper traces its subsequent design history, culminating in the 1098 cm3 version for transverse installation. Originally designed for the post-war Austin 7 saloon, this engine was reclassified as the ‘A’ series unit at the time of the formation of the British Motor Corporation. It was then decided that this unit and its derivatives would power all the smaller range of B.M.C. cars. After a logical development to 950 cm3 a new design situation was created by the concept of the ADO.15 which subsequently evolved into the Mini 7 and Mini Minor. During this period both two-stroke engines and a two-cylinder version of the ‘A’ series were developed, but were discarded in favour of the 850 cm3 four-cylinder unit. The reasons for this decision, which include both economic and technical considerations, are discussed in detail. The modifications required to suit the transverse installations are also considered. A further design challenge was presented by the power requirement for the ADO.16, especially as the relatively high power/weight ratio of the Minis had set a high standard in this respect. The decision was complicated by the existence of an alternative engine in the design stage, and the rigid limitations imposed by existing production plant on the basic dimensions of the ‘A’ series. Previous design criteria had to be discarded in order to make the 1098 cm3 possible, and to establish it as a reliable high-performance unit. The situation was complicated by the need for still greater performance in sports car installations. Apart from specific details of changes in component design which included the adoption of new materials when required, the paper emphasizes the importance of close liaison between design and development.
Paper 10: Stresses in the Contact Zone
Authors: Ollerton E. 
Published: June 2010

The paper deals with the contact-stress problem with particular reference to adhesion in the rail-wheel contact situation. The methods of calculation of the size, shape and orientation of the contact area are described, and confirmed by the results of frozen-stress photoelastic tests. The test results are confined to the contact surface, since sub-surface stresses are not directly relevant in the adhesion problem. The distributions of surface shear stress resulting from the application of tangential forces to different shapes of contact area are described for static and rolling conditions. Methods of calculating the creep of rolling bodies are also considered. The problem of bodies rolling and spinning about an axis normal to the contact area is not so well understood, but a brief description is given. The effects of bending stresses in rails and of the size of the contact area in relation to the railhead are discussed briefly.
Paper 6: Complete Characteristics for a Single-Stage Axial-Flow Fan
Authors: Turner R. C. , Sparkes D. W. 
Published: June 2010

The characteristics of an axial-flow fan, pump or compressor stage are usually established by prediction or test for the normal directions of rotation and flow only, the flow range being restricted to fairly narrow limits. There are occasions, however, when it is desirable to know the performance over a wider range of conditions. Fans in certain types of aircraft jet engines may have to work in reverse through flow or may be required to windmill freely. Fans in high-pressure closed-circuits, or in parallel with other fans, may also have unusual conditions imposed on them if some part of the system fails. This paper presents the characteristics of a single-stage axial-flow fan for normal and reverse rotation and for a wide range of normal and reverse through flow. Several methods of presentation are employed. Published data on the subject is scarce, and it is thought that these characteristics will give a general picture of the trends to be expected with other designs of fan operating under comparable conditions.
Paper 10: Unsteady Flow in Simple Branch Systems
Authors: Benson R. S. , Woollatt D. , Woods W. A. 
Published: June 2010

The paper describes a theoretical and experimental investigation into unsteady flows in simple branch systems. In order to simplify the analysis one-dimensional unsteady flow theory is used to analyse the wave action in the pipes. The method of characteristics is used for this purpose, and both homentropic and non-homentropic flows are investigated. The boundary conditions at the branch are represented by quasi-steady flow theories. Two such theories are examined, the first called the constant pressure theory assumed no pressure change across the branch at the junction. A full graphical treatment is given elsewhere (4). In the paper the assumptions and the formulation of the equations for an electronic computer are briefly discussed. The second method assumes a pressure drop across the branch at the junction. An approximate theoretical method of estimating the pressure drop with certain types of flow is given. Using experimentally determined steady flow loss coefficients at the junction the expressions used in the second method are formulated for direct computation using a digital computer. The results are given of an extensive experimental investigation to test the validity and limits of the theories described above. Steady flow experiments to evaluate the loss coefficients at the junction over the range of pressure and flow directions covered by the unsteady tests are described. The unsteady flow tests on a special multi-cylinder pulse generator are discussed in detail. The results show that under certain conditions the calculated pressure diagrams using constant pressure theory do not agree with the experimental diagrams, both the pulse shape and amplitude being incorrect. Using the pressure drop theory together with experimentally determined steady flow loss coefficients there is considerable improvement in the theoretical diagrams. Agreement is obtained over a wide range of flows.
Paper 12: Turbulent Flow and Heat Transfer in Concentric and Eccentric Annuli
Authors: Lee Yung , Barrow H. 
Published: June 2010

Fluid flow and heat transfer in non-circular passages, with peripheral variation of heat flux around their boundaries, is of particular interest in the nuclear engineering field. This paper deals with heat transfer to air (Prandtl number ⋍ 0.7) in fully-developed turbulent flow in an annular passage, the outer boundary of which is insulated. Experiments have been conducted on annuii whose radius ratios are 1.632, 2.583, and 3.875 over a Reynolds number range 10 000–50 000. Pressure drop, velocity and temperature distributions in the cross-section have been measured over the whole range of eccentricity of the annulus geometry. The effect of eccentricity on average friction, average heat-transfer coefficient, and wall temperature distribution for uniform heat generation within the heated boundary has been studied. The results of the experimental programme are compared with the semi-theoretical predictions and experimental data of other workers in this field. For completeness, a theoretical equation for the heat-transfer coefficient in an internally heated concentric annulus has been derived.
Paper 15: Performance of Extended-Surface Tube Matrices for Gas-Liquid Heat Exchangers
Authors: Rounthwaite C. , Nicholson V. 
Published: June 2010

Heat-transfer experiments have been undertaken, using two different test facilities, on a wide variety of tube bundles arranged with warm gas flowing either across, or parallel to, the outside of the tubes and with cool water flowing inside them. The cross-flow tube bundles include radial-finned tubing in various ‘in-line’ formations, as well as a staggered arrangement of elliptical-section finned tubing. Of the two axial-flow tube bundles considered one is of radial-finned tubes and the other of longitudinal-finned tubes. The gas-side heat-transfer and pressure-drop performance of all these tube arrangements are presented firstly in the form of the customary non-dimensional relations. The performances of the tube matrices are then compared using a number of utilization parameters, based on theoretical expressions of Colburn, covering not only the main factors involved in the cost of heat exchangers, but also the return of heat transfer for the gas-side pressure drop expended. By plotting graphs connecting these parameters, the relative merits of the various tube configurations in actual heat-exchanger applications can be assessed, and conclusions drawn as to the most suitable one to adopt for a particular purpose. A most useful graph is one connecting the parameters expressing the compactness of the tube matrix and the gas-side fluid resistance (see Fig. 15.8). Such a relation shows that the staggered cross-flow arrangement of elliptical tubes gives rise to reasonably compact matrices with only a moderate gas-side pressure drop. The cross-flow bundles of circular-section tubing, however, can result in extremely compact matrices having a high pressure loss, whilst the axial-flow configurations have exactly the opposite characteristics.