Automotive lubricants reference book

Automotive Lubricants

Reference Book

Second Edition

First Edition by

Arthur J. Caines

and

Roger F. Haycock

Revised and Updated by

Roger F. Haycock

and

John E. Hillier

-=International" EAlC

Warrendale, Pa.

All rights reserved. No part of this publication may be reproduced, stored in a retrieval sys￾tem, or transmitted, in any form or by any means, electronic, mechanical, photocopying,

recording, or otherwise, without the prior written permission of SAE.

For permission and licensing requests, contact:

SAE Permissions

400 Commonwealth Drive

Warrendale, PA 15096-000 1 USA

E-mail: [email protected]

Tel: 724-772-4028

Fax: 724-772-4891

Library of Congress Cataloging-in-Publication Data

Caines, A. J. (Arthur J.), 1932-

Automotive lubricants reference book / Arthur J. Caines,

Roger F. Haycock-2nd ed. I revised and updated by Roger F.

Haycock and John E. Hillier.

p. cm.

Includes bibliographical references and index.

1. Lubricating oils. 2. Automobiles-Lubrication. I.

Haycock, R. F. (Roger F.) 11. Hillier, John E. 111. Title.

ISBN 0-7680-1251-1

TL153.5.C35 2004

629.25’5-dc22 2004048248

SAE

400 Commonwealth Drive

Warrendale, PA 15096-0001 USA

E-mail: [email protected]

Tel:

Fax: 724-776- 16 15

877-606-7323 (inside USA and Canada)

724-776-4970 (outside USA)

Copyright 0 1996,2004 SAE International

SAE Order No. R-354

ISBN 0-7680-125 1-1

Printed in the United States of America.

About the Authors

Arthur Caines, Roger Haycock, and John Hillier together have about 100 years of

combined experience in the automotive lubricants field.

Arthur Caines spent 30 years with Esso (Exxon) in Europe, mainly in formulating

crankcase oils. He worked as EuropeanlAfrican business coordinator for Esso's

Paramins Additive Division, coordinated technical services for the Middle East and

central Europe, and was responsible for quality control specification and customer

information for Paramins products.

Roger Haycock spent more than 35 years working for the Exxon group of compa￾nies, 30 of which were with Paramins in a variety of management positions. For the

past five years, he has been an independent consultant on fuel and lubricant topics.

Haycock has served as chairman of the British Technical Council of the Motor and

Petroleum Industries and represented British interests on the Coordinating European

Council (CEC). He was also an active representative of the European petroleum

additives industry.

John Hillier spent more than 30 years working for British Petroleum at the BP Research

Center. He was responsible for crankcase oil development and associated research

programs, with an active role on several key CEC Technical Committees. In addition

to lecturing, Hillier was the external consultant to Ricardo Consulting Engineers for

10 years, providing advice on specialist fuel and lubricant evaluations for oil industry

clients and resolving lubricant-related issues in support of new engine technologies.

Preface to the

First Edition

When asked by SAE to write a companion volume on lubricants to its Automotive

Fuels Handbook, we asked ourselves a series of questions:

Who are the expected readers?

What depth of coverage is needed for each topic?

Do we have the experience and knowledge to author such a book?

Discussion with the SAE Publishing Division enabled satisfactory answers to be made

to these and other questions, and we hope the resulting volume will be a useful con￾tribution to the rather limited literature on the topic.

Firstly, the book is not intended for those who are already experts in the field of

automotive lubrication. Prospective readers will be automotive engineers who may

want to understand more about the properties and composition of lubricants used in

the machinery with which they are concerned, or possibly scientists or engineers in

the petroleum industry, who have worked in another field and need a primer on lubri￾cants for the specialized area of automotive applications.

The depth of coverage is limited by the number of topics we felt needed to be included

in the one volume and is broadly in line with that of Automotive Fuels Handbook.

Our treatment of the subject matter is essentially qualitative, and the use of math￾ematics is minimal. As we have found in the initial reviews of the text, those who are

expert in any of the topics we cover will feel our coverage is too simplistic for their

own areas, but may well feel other areas are dealt with adequately. Our advice to

them is not to linger over the areas they already know.

There may be surprise at the authorship by two Englishmen with similar career paths

within one corporation, albeit a major international one. We hope that we can high￾light complexities that may be difficult to appreciate from a North American view￾point. Also, through our U.S. connections, we have had very strong links with North

American lubricant activities, while being able to relate directly to European atti￾tudes and developments. Colleagues in the Asia-Pacific region have helped with

Japanese and other developments from that area.

vii

Automotive Lubricants Reference Book

Both of us have worked in both the petroleum and chemical sectors of Exxon

Corporation, mainly in areas where lubricant testing was an important factor. How￾ever, the views expressed are our own and not necessarily those of our past or present

employer. A.J.C. had close contacts with the U.S. military, particularly in the 1970s

when they were key actors in the improvements of oil quality, and later worked closely

with the national petroleum companies ofAfrica, the Middle East, and Eastern (now

called Central) Europe. R.F.H. has had close contacts with European approval orga￾nizations, spent ten years in liaison with the motor industry, acquiring a good under￾standing of lubricant problems as seen by that industry, and is currently the chairman

of the British Technical Council of the Motor and Petroleum Industries. Both of us

have seen motor oils develop from uncompounded monograde oils to the sophisti￾cated part or wholly synthetic wide energy-conserving multigrades of today.

Readers will notice that we have frequently taken a historical approach in our presen￾tation of the various topics. This is deliberate, because oil qualities have evolved

steadily over the last half century, with no major discontinuities, and we believe an

understanding of how this evolution took place is necessary to understand oil quality

today.

We give considerable attention to specifications and oil approval systems. The desire

for products to have the widest coverage of equipment and geographical areas usu￾ally conflicts with the ever more complex needs of specific markets. Specifications

often have short lives, but the organizations that develop them last much longer and

are key actors in the lubricants business.

Few existing books give much discussion of the relationship between test methods

and formulation technology, and we have tried to cover this adequately. While the

fundamentals of formulation are presented, detailed formulations to meet specific

quality levels precisely cannot be given. Such formulations are proprietary to formu￾lating companies, whether oil company or additive supplier, and each formulator has

different components and expertise to utilize in producing an oil to meet a given

quality. Furthermore, the optimum means of meeting a given quality level can change

quite rapidly, requiring running changes within the life of a specification, and so a

precise formulation often has a short life.

Much of the book is given over to engine oils, but other automotive lubricants such as

transmission oils and greases are considered. We have also included a brief section

on the key features of the industrial oils that may be used in the production of auto￾motive equipment, in the belief that this will be of interest and useful to those work￾ing in the automotive industry. Our coverage of the blending, handling, and use of

... Vlll

Preface to the First Edition

lubricants is probably unique in a book of this type, and our attention to health and

environmental aspects of lubricants reflects the growing concerns in these areas.

We have collected in the appendices some of the less readily digestible material that

we felt should be included to make the book a work of reference, and we hope we

have succeeded in keeping the main sections both interesting and easily readable.

We have also included a glossary, a list of relevant acronyms, and, for those who

studied chemistry a long time ago, a primer in organic chemistry.

A.J. Caines

R.F. Haycock

May 1996

ix

Preface to the

Second Edition

Having reviewed the style and structure of the first edition, we felt that although both

could no doubt be improved, there was no obvious pressing need for major changes.

Our objective, therefore, when writing the second edition, was to make changes only

where necessary because technology or markets had changed. But both have indeed

changed considerably and continue to change rapidly in many areas.

Two forces have had major impacts on the automotive lubricants industry since the

first edition of this book was published in 1996. The first has been the continuing

drive for improvements in the environment, particularly air quality. This has forced

reduction in vehicle exhaust emissions, which in turn has driven changes in engine

design and exhaust aftertreatment. This in turn has led to changes in lubricant speci￾fications and quality.

Existing pressures to reduce chlorine have been complemented by pressures to reduce

phosphorus, sulfur, and all ash-forming metals in automotive crankcase lubricants.

The impact of the reduction or elimination of zinc dialkyl dithiophosphate (ZDDP)

from most crankcase oils cannot be overestimated. Most engines over the last 50 years

have been designed and run on ZDDP-containing oils, and there must be a real con￾cern that some of them will suffer problems with “new technology” lubricants.

Again, driven primarily by emissions concerns, the move away from “conventional”

to “unconventional” base stocks for mainstream crankcase lubricants is growing rap￾idly. Already significant for several years in Europe, the trend is probably now

unstoppable in the United States.

The question whether crankcase oil technologies in the major world markets will

converge or diverge continues to be unanswerable. In principle, one should expect

worldwide environmental pressures to force convergence. But fine details in legisla￾tion may have great significance, leading toward or against, for example, the use of

exhaust gas recirculation (EGR), which has a huge impact on lubricant formulation.

Oil-change periods around the world continue to differ with little technical justifica￾tion. Why should passenger-car oil-change intervals be little more than 5000 km

(3000 mi) in the United States, when in Europe the leading OEM is encouraging an

oil-change period of 30,000 km (1 8,000 mi) with recommended lubricants?

V

Automotive Lubricants Reference Book

Air quality requirements have almost eliminated the two-stroke motorcycle market

and driven it to four-stroke. Environmentally driven fuel changes have also in turn

impacted on the lubricant. Concerns for water quality have had an impact on out￾board motor lubricants. Concerns for fuel economy (driven partly by global warming

concerns) have influenced lubricant viscosities downward and have encouraged the

move to unconventional base stocks. Fuel economy is also the driving force for

alternative transmission technologies such as continuously variable transmissions

(CVT), traction systems, and dual-clutch transmission (DCT) technology-all requir￾ing modified transmission fluids for optimum performance.

Environmental issues feature directly as well as indirectly-tighter controls on the

manufacturing and marketing of new chemicals and formulations, tighter controls on

product labeling, and tighter controls on the disposal of used lubricants. These issues

are addressed in Chapter 10.

The second major influence has been the consolidation within the oil and petroleum

additive industries. There are now far fewer companies in these industries than there

were six years ago. There are fewer people to develop new test methods or attend

technical society meetings. The full impact of this change is yet to be felt, but it has

already forced some change in technical society structure, and more will surely fol￾low. The motor industry’s need for rapid changes in specifications may be opposed

more strongly by an oil industry needing a better return on its investment in new

lubricant technology.

All of these influences have seen changes throughout this second edition of the book,

but particularly in Chapters 4,6,7,8, and 11. We have also taken the opportunity to

make significant changes to the sections on greases, industrial lubricants, and rail￾road oils.

R.F. Haycock

J.E. Hillier

August 2003

vi

CHAPTER 1

Introduction and

Fundamentals

1.1 Lubricants in History

A lubricant can be defined as a substance introduced between two surfaces in relative

motion in order to reduce the fiction between them. It is not known precisely when

lubricants were first deliberately and consciously used, but various forms of primi￾tive bearing were known in the Middle East several thousands of years B.C. It is

reasonable to assume that if the concept of a bearing had been developed, then the

use of a lubricant with that bearing was highly likely, even if only water. A

Mesopotamian potter's wheel dating from 4000 B.C. contained a primitive bearing

with traces of a bituminous substance adhering to it. This suggests the use of a lubri￾cant originating from surface petroleum deposits in the area. By 3000 B.C., wheeled

chariots were in extensive use in the Middle East, although few traces of lubricant

materials have been found associated with remnants of such vehicles. A notable

exception of a somewhat later period is a well-preserved Egyptian chariot of 1400 B.C.

with definite traces of both chalk and animal fat in the wheel hub, suggesting that a

primitive grease had been in use.

Egyptian murals dating to about 2000 B.C. show statues being dragged along the

ground, with liquids being poured ahead of a transporting sledge, presumably as a

lubricant. There has been much speculation as to whether these liquids were water,

natural oils, a type of liquid grease, or even blood. Dowson in his excellent book

History ofTribology' suggests these statues were, in fact, pulled along balks of tim￾ber lubricated by water, and he actually reconciles the expected hctional resistance

for such a system against the magnitude of the slave power depicted in the hieroglyphs.

The Greek and Roman civilizations produced many devices based on the wheel,

including lathes, pulleys, gears, and crane mechanisms. From the remains of a Roman

ship that was recovered in the 1930s,* we know that the principle of ball and roller

bearings was understood at this time. Pliny in the first century A.D. listed the known

lubricants that could be used in machinery of the era, these being principally animal

Automotive Lubricants Reference Book

fats and vegetable oils. This remained the situation until the industrial revolution,

with olive oil being common in southern Europe, and oil derived from various seeds

such as rape (colza) and linseed being more commonly applied in the north and west

of Europe. Petroleum would have been used in those places where it was available as

surface seepages, notably in Russia and the Middle East.

The industrial revolution started in Britain around 1760 and lasted for about 80 years.

During that time, the development of large-scale machinery based on iron and steel

was achieved, the steam engine was invented, and the concept of the railway devel￾oped with self-propelled steam locomotives. To lubricate all this machinery, animal

oils such as sperm oil (from the sperm whale) and neatsfoot oil (from animal hooves)

were added to the existing lubricants, while palm oil and groundnut oil were imported

to supplement the locally available vegetable oils. During the period, mineral oils

obtained from the distillation of coal or shales also became available as the residue

when a light-illuminating grade of petroleum had been distilled off. Graphite (black

lead) and talc also came into use as solid lubricants for sliding surfaces.

Greases were developed originally by combining soda and animal oils. Later, lime

was also used, and solid lubricants added to the greases provided further anti-friction

properties.

Early use of mineral oils involved distilled coal or shale residues, as previously

described. However, in the 185Os, small quantities of petroleum oil began to be

produced in the United States, Canada, Russia, and Romania. From the 1 88Os, petro￾leum was produced in quantity from wells in the United States, and the modem petro￾leum industry was born. Liquid petroleum must be distilled and “fractionated” into a

range of products in order to be fully exploited, and the heavier of these can find use

as lubricating oils. It was soon discovered that by distilling under reduced pres￾sure-so-called vacuum distillation-fractions could be separated without the heavier

products oxidizing and deteriorating. This is because the boiling point of the frac￾tions is reduced as the pressure is lowered, and lower temperatures are sufficient to

separate the mixture. By the 1920s, superior lubricants were being produced by

vacuum distillation, and some of these fractions were being combined with soaps to

form greases.

Additives to improve performance of petroleum-based oils were developed and saw

increasing use in the 1930s. Initially seen as ways to improve the physical properties

of the lubricants, the ability to control the deterioration of the oil itself became more

and more important as the use of the internal combustion engine grew. This led to the

development of the so-called “detergent” lubricant additives, which both reduced

the oil oxidation and reduced the formation of deposits in engines. These were

2

lnfroducfion and Fundamentals

increasingly used in diesel engines from the 1940s, but began to be used significantly

in gasoline engines only a decade later. Sludge-reducing additives were developed

around this time and saw increasing use in gasoline engines from the 1960s and in

diesel engines from 1970. Modern lubricants are now highly specialized and com￾plex products. Later in this book, we will discuss their technical requirements and

how these are met by combinations of base stocks and additives. Additives of vari￾ous types now form a considerable proportion of the more sophisticated oils, of which

crankcase lubricants are the largest and best-known example. A discussion of the

principal additive types and their modes of operation will be included in Chapter 2.

In Chapters 4,7, and 8, we will discuss how base stocks and additives are combined

to meet the technical requirements of modern lubricants.

Conventional petroleum base stocks have become less able to satisfy the most severe

modem demands, particularly for high-temperature performance, and significant addi￾tions of synthetic or specially refined petroleum stocks are now common in passenger￾car oils. In the fiture, for the most demanding applications, conventionally fractionated

and refined base stocks may have to be replaced almost entirely by synthetic stocks

or base stocks produced from petroleum in new ways. The arrangement of base

stocks into “groups” is discussed in Section 2.1.2 of Chapter 2.

1.2 Functions of a Lubricant

The basic functions of a lubricant are, of course, to reduce friction and prevent wear.

In practice, lubricants are called upon to fulfill other functions, some of which are

equally vital to the operation of the equipment in which they are employed. The

automobile and engine manufacturer Mercedes-Benz (now DaimlerChrysler) has listed

more than 40 properties required from engine Specialized lubricants such as

hydraulic or transmission oils will add other properties for our consideration, whereas

solid and semi-solid products such as greases have more restricted functions and

properties measured in special ways.

The desired properties can have positive aspects (e.g., the oil shall prevent wear) or

negative aspects (e.g., the oil shall not corrode the engine parts). The ability of an oil

to meet any particular requirement is usually a matter of degree, rather than an abso￾lute fact. Therefore, questions of testing and test limits and the acceptance of limita￾tions of both lubricants and machine must be taken into account.

A simplified list of the positive properties particularly applicable to a motor oil can

be given as follows:

3

Automotive Lubricants Reference Book

1.

2.

3.

4.

5.

6.

Friction reduction. This reduces the energy requirements to operate the mecha￾nism and reduces local heat generation.

Wear reduction. An obvious need for keeping the equipment operating for a

longer period and in an efficient manner.

Cooling. In an engine, the lubricant is an initial heat transfer agent between

some parts heated by combustion (e.g., pistons) and the heat dissipating systems

(e.g., sump, cooling jacket). In addition, and in other systems, the lubricant

dissipates heat generated by friction or the mechanical work performed.

Anti-corrosion. Either from its own degradation or by combustion contamina￾tion (see Section 1.7.2 of this chapter), the oil could become acidic and corrode

metals. Moist environments and lack of use can also cause rusting of ferrous

components. The lubricant should counter all of these effects.

Cleaning action. The oil should prevent fouling of mechanical parts from its

own degradation products or from combustion contamination. Deposits, usually

classified by descriptive terms such as “solid carbon,” “varnish,” or “sludge,”

can interfere with the correct and efficient operation of the equipment. In extreme

cases, piston rings may become stuck and oil passages blocked, if the oil does

not prevent these effects. Deposit prevention and the dispersion of contaminants

are included under this heading.

Sealing. The oil should assist in forming the seals between pistons and cylinders

(pistons to rings, and rings to cylinder walls).

In addition to providing these functions on a continuing and economical basis, a

lubricant must have certain properties that are dictated by the equipment in which it is

used. There are necessary compromises between antagonistic requirements, some

listed as negative limitations, as summarized next.

An oil should not:

1. Have too low a viscosity. This will allow metal-to-metal contact and subse￾quent wear, and can increase oil leakage.

2. Have too high a viscosity. This will waste power and, in the case of engines,

cause starting difficulties.

3. Have too low a viscosity index. This means that it must not thin down too much

when hot (or thicken too much when cold).

4

Introduction and Fundamentals

4.

5.

6.

7.

8.

9.

10.

Be too volatile. High volatility will appear as a loss of oil (i.e., high oil con￾sumption) from the boiling away of the lighter constituents, and it has been said

to also cause deposits.

Foam unduly in service. If an oil foams, this can result in loss of the lubricating

properties of the oil, andor loss of the oil itself from the engine.

Be unstable to oxidation or chemical attack. Engine oils in particular are

subject to high temperatures and contamination by acids and other chemicals.

The oils must be resistant to these to preserve their beneficial properties.

Attack emission systems components, coatings, or seals. Some equipment

contains paints or coatings, and most have elastomeric sealing components. None

of these should be seriously degraded by the oil.

Produce deposits from residues. If an oil decomposes on hot metal compo￾nents (e.g., in the ring zone), it produces oxidation products that polymerize to

form a yellow or brown layer known either as “varnish” or “lacquer.” This can

build up and further carbonize to “solid carbon.” Either type of deposit can

prevent movement of parts that should be free to move (e.g., the piston rings).

Apart from not producing deposits on moving parts in an engine, the lubricant

should also not cause significant deposits in the combustion chamber, which

would lead to pre-ignition.

Be unduly toxic or of unpleasant odor. This requirement is for the comfort

and health of the user.

Be unduly costly. This is often a real restraint, not because expensive oils are

not worthwhile in terms of engine operating economics, but because competition

among suppliers limits the price that can be charged to the user, and hence the

acceptable ingredient cost.

These requirements are studied in greater depth in subsequent chapters.

1.3 Approval of Lubricants for Use

Having discussed in broad terms the properties required in a lubricant, and before we

consider in detail the tests that can be performed to measure such properties, we

would like to consider how a lubricant user can determine if a given lubricant is

suitable for that user’s intended purpose. Of course, in the simplest case, the user can

take the word of the supplier, who might state, “This oil is suitable for all modem

5

Automotive Lubricants Reference Book

automobiles.” Such a bold statement is, in fact, unlikely to be found, and the supplier

will more likely refer to different oil specifications that he claims the oil will meet.

Reference to the vehicle handbook or operator’s manual will indicate the specifica￾tion requirements of suitable oil, and the user can see ifthey match. If so, the user can

proceed on the basis that the supplier’s claims are valid. In effect, he approves of his

own use of the oil.

An easier approach is if the vehicle manufacturer has approved certain oils or types

of oil and lists these in his manual. Practices differ in different countries, and in some

cases, only one brand and grade of oil will be officially approved. In others, several

competing brands of similar qualities will be listed, and in others, lubricants approved

by some official body and carrying a certification mark will be specified. In the

United States and possibly in other countries in the future, the American Petroleum

Institute (API) “doughnut” and the API (formerly the International Lubricant Stan￾dardization and Approval Committee, or ILSAC) “starburst” certification mark rep￾resent such “seals of quality.”

Approvals can therefore be given by the lubricant user, the vehicle (or engine) manu￾facturer, or some independent body. In Chapter 6, we will examine in detail the

organizations and procedures employed, but some historical background at this point

will provide a useful perspective for the next sections.

The approving of lubricants for use initially was done on a very simple empirical or

trial-and-error basis, simply seeing if the equipment would operate for a satisfactory

length of time on the oil being evaluated. However, in the 1930s, there was an

upsurge of studies into friction and lubrication and the development of tests that

could distinguish one lubricant from another in several different ways. The impor￾tance of viscosity was soon realized, as well as the need to be aware of properties

such as solidification or pour point, and acidity or corrosiveness. Gradually, a pattern

of product development arose, which consisted of control of fundamental properties

such as viscosity, pour point, and acidity, together with other properties measured in

laboratory gadgets that tried to simulate operating conditions-in other words, in

“rig tests.” Final approval for use of a lubricant was usually based on practical

experience obtained by testing the lubricant in the equipment and service for which

it was designed. This field service experience would also be used to set oil-change

intervals.

A significant change took place at the end of the 1930s, which introduced the concept

of testing oils in real engines but in the laboratory. In the mid-l930s, the Caterpillar

Tractor Company had produced a range of heavy-duty tractor and earth-moving equip￾ment with sophisticated high-power diesel engines. Under the typical severe service

6

Introduction and Fundamentals

conditions for which they were designed, it was found that the pistons rapidly became

carbonized and the rings stuck, so that efficient operation lasted for only a short

period. It was found that metal soaps dissolved in the oil were effective in alleviating

this carbonization; thus, the first “detergent” additive was developed. This was alu￾minium dinaphthenate. The problems of screening new and differing lubricants for

detergency quality by field testing soon became apparent, and Caterpillar embarked

on the development of a laboratory engine test that would permit rapid screening of

the new oils. It was joined by the U.S. military and U.S. Navy laboratories. The first

engine test was ready for use in 1940 and immediately became part of a lubricant

specification employed for screening oils for both Caterpillar and other severe diesel

engines.

Development of products and means of testing and approving them in the laboratory

proceeded rapidly from this time but was given even greater acceleration during World

War 11. The wartime needs of military and aviation equipment, and the difficulties of

providing adequate servicing routines, rendered it imperative to set at least minimum

standards for the quality of lubricants being purchased for the armed forces. The

U.S. Army introduced its specifications 2- 104 for heavy-duty detergent oils in 194 1,

to be elaborated in 2-104B in 1943. In 1943 also, the U.S. Navy (whose great interest

was in operating diesel-engined submarines without breakdown problems) issued its

14-0-13 specification. The U.S. armed forces and other military bodies around the

world continued to develop specifications and to be leaders in setting standards of

performance until the 1980s. In Europe, for cost reasons, parallel engine tests were

developed in smaller locally available engines, initially to provide approximately equiva￾lent tests to those used in the United States, but later to develop different European

specifications. The large size of today’s lubricant-testing industry, particularly the

part that relates to testing in engines run on laboratory test beds, arose initially from

the boost given in wartime by the need to screen lubricants.

The military approval of lubricants represents a case where the user of the equipment

is setting requirements and standards for quality, rather than that being done by the

manufacturer ofthe equipment. For a long time, military authorities around the world,

and particularly the U.S. military, set the standard by which lubricants were judged.

The underlying philosophies behind these standards were not always uniform. For

example, the U.S. military, using the expertise of equipment manufacturers on its

committees, developed a specification and approval system that was available to oil

companies in most non-Comecon countries and that provided standards and lubricant

approvals to rationalize quality levels around the world. In Europe, the British and

other military authorities worked with the oil companies and developed their own

tests and quality philosophies, and had smaller-scale approval systems in their areas

of influence. During the 1980s, the role of military bodies declined. Today, the

7