The Motor Vehicle The MotorVehicle Thirteenth Edition T.K. GARRETT CEng, FIMechE, MRAeS Sometime Editor of Automobile Engineer K. NEWTON MC, BSc, ACGI, AMInstCE, MIMechE Late Assistant Professor, Mechanical and Electrical Engineering Department, The Royal Military College of Science W. STEEDS OBE, BSc, ACGI, FIMechE Late Professor of Mechanical Engineering, The Royal Military College of Science OXFORD AUCKLAND BOSTON JOHANNESBURG MELBOURNE NEW DELHI Butterworth-Heinemann Linacre House, Jordan Hill, Oxford OX2 8DP 225 Wildwood Avenue, Woburn, MA 08101-2041 A division of Reed Educational and Professional Publishing Ltd First published by Iliffe & Sons 1929 Eighth edition 1966 Ninth edition 1972 Tenth edition published by Butterworths 1983 Eleventh edition 1989 Twelfth edition 1996 Reprinted 1997 Thirteenth edition 2001 © Reed Educational and Professional Publishing Ltd 2001 All rights reserved. No part of this publication may be reproduced in any material form (including photocopying or storing in any medium by electronic means and whether or not transiently or incidentally to some other use of this publication) without the written permission of the copyright holder except in accordance with the provisions of the Copyright, Designs and Patents Act 1988 or under the terms of a licence issued by the Copyright Licensing Agency Ltd, 90 Tottenham Court Rd, London, England W1P 9HE. Applications for the copyright holder s written permission to reproduce any part of this publication should be addressed to the publishers. British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library. Library of Congress Cataloging in Publication Data A catalogue record for this book is available from the Library ISBN 07506 4449 4 Typeset by Replika Press Pvt Ltd, Delhi 110 040 (India) Printed Great Britain by Clays Ltd, St. Ives plc Contents Preface to the thirteenth edition vii Units and abbreviations ix Part 1 The Engine 1 General principles of heat engines 3 2 Engine balance 25 3 Constructional details of the engine 47 4 Six-, eight- and twelve-cylinder engines 137 5 Sleeve valve and special engines 177 6 Diesel injection equipment and systems 186 7 Distributor type pumps 252 8 Some representative diesel engines 311 9 The two-stroke engine 326 10 Fundamentals of carburation 349 11 Some representative carburettors 385 12 Petrol injection systems 424 13 Induction manifold design 479 14 Emission control 516 15 Fuel pumps and engine intake air conditioning 549 16 Turbocharging and supercharging 556 17 Fuels and their combustion 590 18 Friction, lubricants and lubrication 619 19 Engine cooling 641 20 Electric propulsion 655 21 Alternative power units 669 22 Bearings, gearing, chains and belt drives 698 Part 2 Transmission 23 Transmission requirements 709 24 Clutches 720 25 Why is a gearbox necessary? 750 26 Constructional arrangements of gearboxes 760 27 Epicyclic and pre-selector gearboxes 792 28 Torque converters and automatic gearboxes 806 v vi Contents 29 Semi-automatic gearboxes and continuously variable transmissions 841 30 Universal joints and driving steered wheels 864 31 The differential 876 32 The back axle 892 33 Axle constructions 900 34 The double reduction axle 907 Part 3 The Carriage Unit 35 The basic structure 915 36 Vehicle safety 924 37 Brakes 956 38 Servo- and power-operated, and regenerative braking systems 983 39 Anti-lock brakes and traction control 1015 40 Front axle and steering mechanism 1043 41 Wheels and tyres 1085 42 Suspension principles 1109 43 Suspension systems 1144 44 Six-wheel vehicles 1177 Index 1191 Preface to the thirteenth edition Because of the continuing phenomenally rapid rate of progress in automotive t echnology, the revision for this the thirteenth edition of The Motor Vehicle has been on a major scale. No fewer than seven new chapters have been created. Of these, three are entirely new, while the remaining four comprise mainly new material that could not have been accommodated in existing chapters without making them too long and cumbersome. Of the entirely new chapters, one is on electric propulsion which, owing to pressure of legislation is now beginning to be taken seriously by the industry. It covers all the alternatives, from conventional lead-acid, and other, battery-powered vehicles to fuel cells and hybrid power units. A second covers both static and dynamic safety which, again because of pressure of legislation, is a field in which enormous progress has been made. This progress, which embraces almost all aspects of automotive design, has become possible largely because of the development of computer aided control. The third of these entirely new chapters deals with wheels and tyres. Over the past few decades, wheels and especially tyres have moved on, from being simply components that the designer chose largely on the basis of dimensional and commercial considerations, to becoming an integral part of the tuned suspension system. I n the twelfth edition, only one chapter was devoted to the compression ignition engine. Now, owing to a major extent to the widespread application of diesel power to cars and light commercial vehicles, so much new equipment has been developed that it has now been expanded into three chapters. One of these comprises mainly the original subject matter, while the other two contain a considerable amount of new information on aspects such as common rail injection, recently developed distributor type pumps, and electronic control of injection. Two chapters now cover automatic, semi-automatic and continuously variable transmissions. These contain some of the original material but also information on the Porsche Tiptronic and Alfa Romeo Selespeed semi-automatic transmissions, the latter being basically the Magneti Marelli system. Chapter 39 has been added to contain much of the original material on anti-lock brakes together with new information on some of the latest developments for improving stability by means of computer aided control over both braking and traction. In the next chapter, a significant amount of space is devoted to both the basic considerations and the practice of electrically actuated power- assisted steering, which now looks set ultimately to render hydraulic power assistance systems redundant. In addition to the introduction of new chapters, many of the original ones have new sections covering recent developments such as hydraulically damped vii viii Preface to the 13th edition engine mountings, which are desirable refinements for some vehicles, especially diesel powered cars. New material has been added on the subject of fuel filtration. Particularly interesting are the latest developments of the Merritt engine. By virtue of its recently developed novel ignition system, it can fire consistently from a b.m.e.p of 10 bar right down to idling speed on air : fuel ratios ranging from 30 : 1 to 137 : 1 respectively. Moreover, it might be possible even to dispense altogether with catalytic conversion of the exhaust gases, while still keeping within the stringent emission limits under consideration at the time of writing. Most of the remarkable advances made, especially those over the past ten to fifteen years, have been rendered practicable by virtue of the application of electronic and computer technology to all aspects of automotive engineering, from design, through development, to production and actual operation of the vehicle. Many have been driven by new legislation aimed at increasing safety and reducing atmospheric and other pollution. In general, the two original aims of the book have been maintained. In short, it remains, as the authors originally intended. First, it was intended to be a book that the student could buy that will furnish him or her with all they need to know, as regards automotive engineering; secondly, it will then serve as an invaluable a work of reference throughout the rest of their career. Granted, many students will require knowledge of other peripheral, though no less essential, subjects such as electronics, metallurgy, and production engineering, but these are aspects of general engineering that fall outside the sphere of pure automotive technology. Some details of, for example, electronic systems are given in this book, but it has had to be assumed that readers who are interested in them already have some knowledge of the relevant basic principles. T.K. Garrett Units and abbreviations Calorific value kilojoules per kilogram kJ/kg megajoules per litre MJ/l Specific fuel kilograms per kilowatt hour kg/kWh consumption Length millimetres, metres, kilometres mm, m, km Mass kilograms, grams kg, g Time seconds, minutes, hours s, min, h Speed centimetres per second, metres per second cm/s, m/s kilometres per hour, miles per hour km/h, mph Acceleration metres-per-second per second m/s 2 Force newtons, kilonewtons N, kN Moment newton-metres Nm Work joules J Power horsepower, watts, kilowatts hp, W, kW Pressure newtons per square metre N/m 2 kilonewtons per square metre kN/m 2 Angles radians rad Angular speed radians per second rad/s radians-per-second per second rad/s 2 revolutions per minute rev/min revolutions per second rev/s SI units and the old British units: Length 1 m = 3.281 ft 1 ft = 0.3048 m 1 km = 0.621 mile 1 mile = 1.609 km Speed 1 m/s = 3.281 ft/s 1 ft/s = 0.305 m/s 1 km/h = 0.621 mph 1 mph = 1.61 km/h Acceleration 1 m/s 2 = 3.281 ft/s 2 1 ft/s 2 = 0.305 m/s 2 Mass 1 kg = 2.205 lb 1 lb = 0.454 kg Force 1 N = 1 kg m/s 2 = 0.225 lbf 1 lbf = 4.448 N Torque 1 Nm = 0.738 lbf ft 1 lbf ft = 1.356 Nm ix x Units and abbreviations Pressure 1 N/m 2 = 0.000145 lbf/in 2 1 lbf/in 2 = 6.895 kN/m 2 1 Pa = 1 N/m 2 = 0.000001 bar 1 bar = 14.5038 lbf/in 2 1 lbf/in 2 = 0.068947 bar Energy, work 1 J = 0.738 ft lbf 1 ft lbf = 1.3558 J 1 J = 0.239 calorie 1 calorie = 4.186 J 1 kJ = 0.9478 Btu 1 Btu = 1.05506 kJ (1 therm = 100 000 Btu) 1 kJ = 0.526 CHU 1 CHU = 1.9 kJ Power 1 kW = 1.34 bhp = 1.36 PS 1 hp = 0.7457 kW Fuel cons. 1 mpg = 0.003541/100 km 11/100 km = 282.48 mpg Specific fuel 1 kg/kWh = 1.645 lb/bhp h 1 lb/bhp h = 0.6088 kg/kWh consumption 1 litre/kWh = 1.316 pt/bhp h 1 pt/bhp h = 0.76 litre/kWh Calorific value 1 kJ/kg = 0.4303 Btu/lb 1 Btu/lb = 2.324 kJ/kg Standard gravity 1 kJ/kg = 0.239 CHU/lb 9.80665 m/s 2 = 32.1740 ft/s 2 1 CHU/lb = 4.1868 kJ/kg Part 1 The Engine [...]... turned in the upper part of the piston The pressure of the gases is transmitted to the upper end of the connecting rod through the ‘gudgeon pin’on which the ‘small end’ of the connecting rod is free to swing Fig 1.1 Fig 1.2 8 The Motor Vehicle Connecting rod The connecting rod transmits the piston load to the crank, causing the latter to turn, thus converting the reciprocating motion of the piston... The heat required to raise the temperature of 1 lb of water through 1 °C (1 CHU = 1.9 kJ.) The Kilogram Calorie: The heat required to raise the temperature of 1 kg of water through 1 °C (1 calorie = 4.186 J.) 3 4 The Motor Vehicle The first and second of these units are clearly in the ratio of the Fahrenheit degree to the Centigrade degree, or 5 : 9, while the second and third are in the ratio of the. .. of the engine Flywheel At one end the crankshaft carries a heavy flywheel, the function of which is to absorb the variations in impulse transmitted to the shaft by the gas and inertia loads and to drive the pistons over the dead points and idle strokes In motor vehicles the flywheel usually forms one member of the clutch through which the power is transmitted to the road wheels The foregoing are the. .. below 10 The Motor Vehicle atmospheric pressure by an amount which depends upon the speed of the engine and the throttle opening (b) Compression stroke – both valves closed The piston returns, still driven by the momentum of the flywheel, and compresses the charge into the combustion head of the cylinder The pressure rises to an amount which depends on the ‘compression ratio’, that is, the ratio of the. .. holding an object in the hand and moving it rapidly backwards and forwards in front of the body The speed of the piston is changing most rapidly (that is, the acceleration is greatest) at the ends of the stroke, and it follows that the force required to change the motion is greatest there also At the middle of the stroke the speed is not changing at all, so no force is required The necessary force is... or compression in the connecting rod If the connecting rod were to break when the piston was approaching the top of the cylinder, the engine running at a high speed, the piston would tend to fly through the top of the cylinder just as, if the cord broke, the mass referred to earlier would fly off at a tangent Now the reaction of this force, which is required to slow the piston at the top of its stroke... pressure, and these make it numerically 3% lower than the DIN rating The French CV (chevaux) and the German PS (pferdestarke), both meaning ‘horse power’, must be replaced by the SI unit, the kilowatt, 1 kW being 1.36 PS 1.16 Piston speed and the RAC rating The total distance travelled per minute by the piston is 2LN Therefore, by multiplying by two the top and bottom of the fraction in the last equation... the crankshaft thus propelling the car against the external resistances and restoring to the flywheel the momentum lost during the idle strokes The pressure falls as the volume increases (d) Exhaust stroke – inlet valve closed: exhaust valve open The piston returns, again driven by the momentum of the flywheel, and discharges the spent gases through the exhaust valve The pressure will be slightly above... representing the total heat input, in the form of the potential chemical energy content of the fuel supplied, assuming it is all totally burned in air Then, on the opposite side, place the figures representing the energy output, in the form of useful work done by the engine, and all the losses such as those due to friction, heat passing out through the exhaust system, and heat dissipated in the coolant... of the piston The cylinder is then double-ended and the piston takes the form of a symmetrical disc The force acting on the piston is transmitted through a ‘piston rod’ to an external ‘cross-head’ which carries the gudgeon pin The piston rod passes through one end of the cylinder in a ‘stuffing-box’ which prevents the escape of steam or gas 1.11 Method of working It is now necessary to describe the . rod. The connecting rod transmits the piston load to the crank, causing the latter to turn, thus converting the reciprocating motion of the piston into a rotary motion of the crankshaft. The. British thermal units (Btu). 1.2 Work If work is done by rotating a shaft, the quantity of work is the product of the torque or turning moment applied to the shaft in newton metres, multiplied. drives the piston forward and turns the crankshaft thus propelling the car against the external resistances and restoring to the flywheel the momentum lost during the idle strokes. The pressure