- Email: [email protected]
The relationship between engine oil viscosity and engine performance
total emerges of about 50% potential improvement". 'The Fuel Economy of the Gasoline Engine', edited by D.R. Blackmore and A. Thomas, is published, price £10.00, by Macmillan Press, 4 Little Essex Street, London WC2R 3LF, UK
Cam mechanisms According to Professor Sandor: "Contemporary design procedures for threedimensional cams and followers are at best crudely approximate and often result in rough, noisy operation and rapid wear". He suggests that the analysis of cams presented in 'Kinematics and Geomety of Planar and Spatial Cam Mechanisms' by Chakraborty and Dhande "....Will be of great benefit to designers who deal with the ever increasing number of such mechanisms". A generalised model is constructed to cover the wide variety of cams: it is suggested that all planar and spatial cams are particular.cases of this model. This approach enables such information as cam coordinates, pressure angles, curvatures, etc., for all types of cams to be expressed in closed analytical form. As the title suggests, the book does not cover metallurgy, lubrication, or wear. Published, price £4.50 or $7.90, by John Wiley and Sons Ltd, Baffins Lane, Chichester, Sussex PO19 1UD, UK
Metal arc spraying Metal spraying was introduced ha the UK as a corrosion protection process in 1922. Since then, the range of applications has widened dramatically.
In 1975, IRD started work on a multiclient sponsored project on wear resistant surfaces. The project has been completed with the production of a 300 page report.
Handy, in an article in the November 1977 issue of Chartered Mechanical Engineer, suggests that "...the development of satisfactory arcspraying equipment and materials is the most significant step that has been made in the process during the last 20 years". The article briefly reviews the basic metal spraying processes and then presents a number of applications examples. The applications considered include reclamation of a pitted steel mill journal running in fabricated bearings, of a crane wire barrel, and of the steam drum in a paper mill.
Data on wear resistant surface coatings and treatments was obtained by: reviewing technical and trade literature; examining curren t practice in a range of industries; and evaluating the commercial potential of recent technological developments. Iridustrial users, commercial process operators, equipment manufacturers, coating material producers, research and development laboratories, trade associations, and professional bodies were consulted. Interviews were conducted mainly in the UK, but also in some cases in Europe and North America.
'Growing applications of metal arc spraying' by V.R. Hardy is published in Chartered Mechanical Engineer, Vol 24 No 10, by Mechanical Engineering Publications Ltd, PO Box 24, Nathgate Avenue, Bury St Edmunds, Suffolk IP32 6BW, UK
Results from the study are presented in 'Wear Resistant Surfaces: a guide to their production, properties, and selection'. The principal sections cover: wear mechanisms; process selection; thermal, theremochemical, ele'ctrochemical, and chemical treatments; welding; spraying; chemical vapour deposition; physical vapour deposition; and applications.
Wear study Estimates of the direct and indirect cost of wear in industry have provoked some debate. There seems little doubt, however, that application of available tribological knowledge could cut this cost.
The Relationship Between Engine Oil Viscosity And Engine Performance The nine papers presented in this 116 page 'booklet' comprise a Symposium which was presented at the 1977 SAE International Automotive Engineering Congress and Exposition Meeting held in Detroit from 28th February to 4th March. Despite fascimile reproduction of the authors' original typed manuscript, a uniform styling and format has been specified and the result is not unacceptable. Trouble has also been taken to include illustrations and tables at the appropriate positions in the two-column text - an agreeable
change from the currently increasing practice of placing them inconveniently at the end of each paper. The soft binding is attractive, although rather flimsy for regular reference. The aim of the Symposium, according to the preface, was primarily to encourage international sharing of information in order to assist the Joint SAE ASTM Viscosity Classification Group in the development of a new classification system based upon engine per° formance and, secondly, to identify
80 TRIBOLOGY international February 1978
For further information contact International Research and Development Co Ltd, Fossway, Newcastle-upon-Tyne Tyne, NE6 2YD, UK
and publicise those areas in which more information and further research is required. The need for a new classification system is made patently clear in the first paper, which is a well presented 80 reference, literature survey on the subject, from which the authors attempt to summarise current knowledge on the effects of oil viscosity on some of the more important engine performance parameters, such as bearhag wear, piston ring and cylinder wear, cam and tappet wear, oil and fuel consumption, hot and cold starting characteristics, low temperature pumpability, noise, and oil shear stability. The main conclusions drawn are that while oil viscosity appears to
have a significant influence upon these performance factors, current oil classifications, based on conventional viscometry techniques, are inadequate, particularly for the high temperatures and high shear rates in modern engines. Moreover, it seems that the solution to this problem is not as straightforward as defining a new high-temperature viscosity classification based upon a suitably selected high shear rate, because the combination of temperature and shear rate which might be satisfactory for classifying oils for engine bearing protection, for example, would probably be unsuitable for piston-ring and cylinder contacts. The shortcomings of current oil classifications are also discussed in the second and third papers, which outline past, present and possible future activity in this area. The first of these papers notes that the current classification system is too complex and, again, it is concluded that the hightemperature viscosity grades are based upon unrealistically low temperatures and shear rates for many of the contact conditions met in engines. The author also advocates the inclusion of a 'low temperature pumpability' characteristic in any new viscosity classification system. In the second of these two papers the efforts of the Co-ordinating European Council in attempting to correlate bench tests and engine performance data for high temperature viscosity measurements are described. A preliminary investigation has resulted in the formulation of nine reference multigrade oils which are due, in the near future, to be subjected to 22 engine and laboratory tests in order to identify further correlations. Most of the remaining papers describe the results of tests carried out with laboratory simulator rigs and test engines. A comparison of the results from two papers, one describing laboratory simulation tests on piston ring and cam-and-tappet wear, and the other discussing the results of engine tests on piston ring wear, bearing wear and fuel consumption, further illustrates the problems of attempting to develop a new classification system. The common link between these two papers is piston ring wear and, while the results from the simulator rig experiments indica-
ted that wear performance was not related to viscosity under either high or low shear conditions, the wear results from the engine tests showed good correlation with high shear rate oil viscosities, if not at low shear rates. It is possible that these differences may be due to the way in which the tests were conducted and the way the resuits have been interpreted, but they are equally likely to be due to the inherent difficulties of trying to reproduce engine contact conditions with a simulator rig. As would be expected with such a publication, discussions are not included, since it was almost certainly printed prior to the meeting. This being the case, the booklet suffers from the same problem as many other publications of its type - a lack of complete-
Marine Gearing J.F. Shannon
Dr. Shannon is an enthusiast. An authority in early fife on marine torsional vibrations and singing propellers, he transferred his affections to gas turbines in their exciting early development years and plunged in at the deep end with gears, in the design of the the Royal Navy's most complicated main propulsion set in the late '50's. His enthusiasm is infectious and shows itself in this book which tries to summarise in a few short chapters the vast field of marine gearing. No one with a love of gears can fail to enjoy it. The book takes the form of a review based on information from many sources throughout the United Kingdom and Europe. ~pecifically intended for sea-going engineers and their superintendents, it is possibly a pity that the simple marine diesel gear, which is the one most often met with, has so little space devoted to it. Be that as it may, the volume is so obviously bulging at the seams with information on gearcutting, loading, materials, configurations, epicycles, reversing clutches, couplings, bearings, meshing kinematics, tooth damage, and noise that it is almost greedy to ask for more. In a review of this sort, the sources most cooperative in supplying information
ness. As it stands, this publication is simply nine related, albeit informative, papers bound together in one cover. However, with a little extra effort immediately prior to printing, a tenth paper, which extracted and summed up the main points presented in the nine main papers, would have been a useful addition, serving to round off the booklet. Despite this one small criticism, it must be concluded that this publication does give a good impression of the somewhat inconclusive state-of-theart. Moreover, it achieves, at least in part, its stated objectives and should be of considerable interest to those involved with viscosity classification. J.S. Woodcock Published by ASTM, 1916 Race St, Philadelphia Pa 19103, USA
tend to have the limelight, and this book is no exception. The author does however make obvious efforts to achieve a balanced presentation with, in general, a minimum of 'unfair advertising' on behalf of specific firms. Obviously this is not a text book. It is meant rather to whet the appetite by a demonstration of how much variety the subject holds, and a whole library of references is given at the end for those desirous of further study. I have one small criticism: for an up-todate review it is regrettable that gear notation and units do not conform with the latest international standards. Much as this is understood by the older generation, the young engineer is brought up on the SI system at college and it will not be long before pounds, feet and inches are as incomprehensible to the average reader as Newtons are to the author. The pubfishers must bear some of the blame for this defect and they would be wise to consider a suitable 'translation' if the book is re-published. Otherwise this book highly recommended and, for a specialist subject like this, it is well worth the purchase price. I. 7". Young Published in the Marine Engineering and Design Series by The Institute of Marine Engineers, 76 Mark Lane, London EC3R 7JN, UK. Price £6.50.
TRIBOLOGY international February 1978
81
Cam mechanisms According to Professor Sandor: "Contemporary design procedures for threedimensional cams and followers are at best crudely approximate and often result in rough, noisy operation and rapid wear". He suggests that the analysis of cams presented in 'Kinematics and Geomety of Planar and Spatial Cam Mechanisms' by Chakraborty and Dhande "....Will be of great benefit to designers who deal with the ever increasing number of such mechanisms". A generalised model is constructed to cover the wide variety of cams: it is suggested that all planar and spatial cams are particular.cases of this model. This approach enables such information as cam coordinates, pressure angles, curvatures, etc., for all types of cams to be expressed in closed analytical form. As the title suggests, the book does not cover metallurgy, lubrication, or wear. Published, price £4.50 or $7.90, by John Wiley and Sons Ltd, Baffins Lane, Chichester, Sussex PO19 1UD, UK
Metal arc spraying Metal spraying was introduced ha the UK as a corrosion protection process in 1922. Since then, the range of applications has widened dramatically.
In 1975, IRD started work on a multiclient sponsored project on wear resistant surfaces. The project has been completed with the production of a 300 page report.
Handy, in an article in the November 1977 issue of Chartered Mechanical Engineer, suggests that "...the development of satisfactory arcspraying equipment and materials is the most significant step that has been made in the process during the last 20 years". The article briefly reviews the basic metal spraying processes and then presents a number of applications examples. The applications considered include reclamation of a pitted steel mill journal running in fabricated bearings, of a crane wire barrel, and of the steam drum in a paper mill.
Data on wear resistant surface coatings and treatments was obtained by: reviewing technical and trade literature; examining curren t practice in a range of industries; and evaluating the commercial potential of recent technological developments. Iridustrial users, commercial process operators, equipment manufacturers, coating material producers, research and development laboratories, trade associations, and professional bodies were consulted. Interviews were conducted mainly in the UK, but also in some cases in Europe and North America.
'Growing applications of metal arc spraying' by V.R. Hardy is published in Chartered Mechanical Engineer, Vol 24 No 10, by Mechanical Engineering Publications Ltd, PO Box 24, Nathgate Avenue, Bury St Edmunds, Suffolk IP32 6BW, UK
Results from the study are presented in 'Wear Resistant Surfaces: a guide to their production, properties, and selection'. The principal sections cover: wear mechanisms; process selection; thermal, theremochemical, ele'ctrochemical, and chemical treatments; welding; spraying; chemical vapour deposition; physical vapour deposition; and applications.
Wear study Estimates of the direct and indirect cost of wear in industry have provoked some debate. There seems little doubt, however, that application of available tribological knowledge could cut this cost.
The Relationship Between Engine Oil Viscosity And Engine Performance The nine papers presented in this 116 page 'booklet' comprise a Symposium which was presented at the 1977 SAE International Automotive Engineering Congress and Exposition Meeting held in Detroit from 28th February to 4th March. Despite fascimile reproduction of the authors' original typed manuscript, a uniform styling and format has been specified and the result is not unacceptable. Trouble has also been taken to include illustrations and tables at the appropriate positions in the two-column text - an agreeable
change from the currently increasing practice of placing them inconveniently at the end of each paper. The soft binding is attractive, although rather flimsy for regular reference. The aim of the Symposium, according to the preface, was primarily to encourage international sharing of information in order to assist the Joint SAE ASTM Viscosity Classification Group in the development of a new classification system based upon engine per° formance and, secondly, to identify
80 TRIBOLOGY international February 1978
For further information contact International Research and Development Co Ltd, Fossway, Newcastle-upon-Tyne Tyne, NE6 2YD, UK
and publicise those areas in which more information and further research is required. The need for a new classification system is made patently clear in the first paper, which is a well presented 80 reference, literature survey on the subject, from which the authors attempt to summarise current knowledge on the effects of oil viscosity on some of the more important engine performance parameters, such as bearhag wear, piston ring and cylinder wear, cam and tappet wear, oil and fuel consumption, hot and cold starting characteristics, low temperature pumpability, noise, and oil shear stability. The main conclusions drawn are that while oil viscosity appears to
have a significant influence upon these performance factors, current oil classifications, based on conventional viscometry techniques, are inadequate, particularly for the high temperatures and high shear rates in modern engines. Moreover, it seems that the solution to this problem is not as straightforward as defining a new high-temperature viscosity classification based upon a suitably selected high shear rate, because the combination of temperature and shear rate which might be satisfactory for classifying oils for engine bearing protection, for example, would probably be unsuitable for piston-ring and cylinder contacts. The shortcomings of current oil classifications are also discussed in the second and third papers, which outline past, present and possible future activity in this area. The first of these papers notes that the current classification system is too complex and, again, it is concluded that the hightemperature viscosity grades are based upon unrealistically low temperatures and shear rates for many of the contact conditions met in engines. The author also advocates the inclusion of a 'low temperature pumpability' characteristic in any new viscosity classification system. In the second of these two papers the efforts of the Co-ordinating European Council in attempting to correlate bench tests and engine performance data for high temperature viscosity measurements are described. A preliminary investigation has resulted in the formulation of nine reference multigrade oils which are due, in the near future, to be subjected to 22 engine and laboratory tests in order to identify further correlations. Most of the remaining papers describe the results of tests carried out with laboratory simulator rigs and test engines. A comparison of the results from two papers, one describing laboratory simulation tests on piston ring and cam-and-tappet wear, and the other discussing the results of engine tests on piston ring wear, bearing wear and fuel consumption, further illustrates the problems of attempting to develop a new classification system. The common link between these two papers is piston ring wear and, while the results from the simulator rig experiments indica-
ted that wear performance was not related to viscosity under either high or low shear conditions, the wear results from the engine tests showed good correlation with high shear rate oil viscosities, if not at low shear rates. It is possible that these differences may be due to the way in which the tests were conducted and the way the resuits have been interpreted, but they are equally likely to be due to the inherent difficulties of trying to reproduce engine contact conditions with a simulator rig. As would be expected with such a publication, discussions are not included, since it was almost certainly printed prior to the meeting. This being the case, the booklet suffers from the same problem as many other publications of its type - a lack of complete-
Marine Gearing J.F. Shannon
Dr. Shannon is an enthusiast. An authority in early fife on marine torsional vibrations and singing propellers, he transferred his affections to gas turbines in their exciting early development years and plunged in at the deep end with gears, in the design of the the Royal Navy's most complicated main propulsion set in the late '50's. His enthusiasm is infectious and shows itself in this book which tries to summarise in a few short chapters the vast field of marine gearing. No one with a love of gears can fail to enjoy it. The book takes the form of a review based on information from many sources throughout the United Kingdom and Europe. ~pecifically intended for sea-going engineers and their superintendents, it is possibly a pity that the simple marine diesel gear, which is the one most often met with, has so little space devoted to it. Be that as it may, the volume is so obviously bulging at the seams with information on gearcutting, loading, materials, configurations, epicycles, reversing clutches, couplings, bearings, meshing kinematics, tooth damage, and noise that it is almost greedy to ask for more. In a review of this sort, the sources most cooperative in supplying information
ness. As it stands, this publication is simply nine related, albeit informative, papers bound together in one cover. However, with a little extra effort immediately prior to printing, a tenth paper, which extracted and summed up the main points presented in the nine main papers, would have been a useful addition, serving to round off the booklet. Despite this one small criticism, it must be concluded that this publication does give a good impression of the somewhat inconclusive state-of-theart. Moreover, it achieves, at least in part, its stated objectives and should be of considerable interest to those involved with viscosity classification. J.S. Woodcock Published by ASTM, 1916 Race St, Philadelphia Pa 19103, USA
tend to have the limelight, and this book is no exception. The author does however make obvious efforts to achieve a balanced presentation with, in general, a minimum of 'unfair advertising' on behalf of specific firms. Obviously this is not a text book. It is meant rather to whet the appetite by a demonstration of how much variety the subject holds, and a whole library of references is given at the end for those desirous of further study. I have one small criticism: for an up-todate review it is regrettable that gear notation and units do not conform with the latest international standards. Much as this is understood by the older generation, the young engineer is brought up on the SI system at college and it will not be long before pounds, feet and inches are as incomprehensible to the average reader as Newtons are to the author. The pubfishers must bear some of the blame for this defect and they would be wise to consider a suitable 'translation' if the book is re-published. Otherwise this book highly recommended and, for a specialist subject like this, it is well worth the purchase price. I. 7". Young Published in the Marine Engineering and Design Series by The Institute of Marine Engineers, 76 Mark Lane, London EC3R 7JN, UK. Price £6.50.
TRIBOLOGY international February 1978
81