The Car Engine and Structure The Car Engine and Structure Roy H. Bacon, C.ENG., M.I.MECH.E. SECOND EDITION Macmillan Education ISBN 978-0-333-17322-0 ISBN 978-1-349-15459-3 (eBook) DOI 10.1007/978-1-349-15459-3 ©Roy H. Bacon 1968, 1972 Reprint of the original edition 1972 All rights reserved. No part of this publication may be reproduced or transmitted, in any form or by any means, without permission. First edition 1968 Second edition 1972 Reprinted 1972, 1974 Published by THE MACMILLAN PRESS LTD London and Basingstoke Associated companies in New York Dublin Melbourne Johannesburg and Madras SBN 333 13713 2 (printed cased edition) 333 17322 8 (limp-cover edition) The paperback edition of this book is sold subject to the condition that it shall not, by way of trade or otherwise, be lent, resold, hired out, or otherwise circulated without the publisher's prior consent, in any form of binding or cover other than that in which it is published and without a similar condition including this condition being imposed on the subsequent purchaser. Preface This book is intended for the use of engineers, fitters, maintenance mechanics and students whose careers are concerned with the motor car, particularly for students taking the Associate Membership examinations of the Institute of the Motor Industry, or the City and Guilds Motor Vehicle Mechanics', or Motor Vehicles Technicians', examinations. It may well appeal also to the keen driver who wishes to obtain fuller information, not only on how a car works but also the reasons why certain features of design are used in preference to others. The basic principles of car design and construction are covered fully, with the accent on principles of operation and suitable illustra­ tions of modern practice. Although there is continual development in the industry, the basic principles remain the same and with this knowledge the newest developments can easily be followed. In accordance with the policy of teaching basic principles, the great majority of the illustrations are diagrammatic only, and illustra­ tions of the whole or of part of particular cars and engines are used only occasionally, as examples. In this second edition, the opportunity has been taken to include a table allowing conversion of Imperial units to metric equivalents, and at the same time minor corrections and amendments to the text have been incorporated. The author, a professional design engineer, was Chairman of the Bantam Racing Club from 1963 to 1969 and is the author of seven books on cars and motor cycles. The jacket design illustrates the Rover 2000 TC engine and is here reproduced by kind permission of the Rover Company of Solihull. Contents Preface v Conversion Factors X 1 Engine Types and Cycles 1 The Use of Energy - The Basic I.C. Engine Cycle - The Four- stroke Cycle-The Four-stroke Engine- The Two-stroke Cycle - The Two-stroke Engine 2 Fuel into Power 10 Introduction - Volatile Fuels - Combustion - Detonation - Octane Values- Pre-ignition- Compression Ratio- Anti-knock Fuels - Special Fuels - The Heat Value of Fuels -Thermo- dynamics- Cylinder Pressures- Horsepower- Tor(:ue-Thermal Efficiency- Volumetric Efficiency- Horsepower omparison- Heat Losses 3 Practical Engine Layouts 22 Introduction - The Induction System - Valve Systems - The Ignition System - The Cooling System - The Lubrication System - The Single-cylinder Engine - Twin-cylinder Engines - Three Cylinders in Line- Four-cylinder Engines- Six-cylinder Engines - Eight-cylinder Engines - Twelve-cylinder Engines 4 The Cylinder Head, Valves and Valve Gear 35 Combustion Chamber Design - The Cylinder Head - The Side Valve Engine- The Overhead Inlet, Side Exhaust Valve Engine- The Overhead Valve Engine- Valves- Valve Guides- Valve Springs- Rotating Valves- Valve Rockers and Shafts- Tapgets and Pushrods- Desmodromic Valve Operation- The Cams aft and its Drive- Four-valve Engines- Sleeve and Rotary Valve Engines- Valve Timings- The Manifolds- The Silencer s The Cylinder Block, Crankcase and Connecting Rods 60 The Cylinder Block and Crankcase - Flat-four Construction - Aluminium Cylinders- Cylinder Head Gasket-The Sump-The Crankshaft - The Connecting Rod - Main and Big End Bearings -The Flywheel 6 Pistons and Rings 72 The Piston - The Gudgeon Pin - Piston Rings viii CONTENTS 7 Carburation and Petrol Systems 79 The Problem- The Fixed Choke Carburettor - The Variable Choke Carburettor- Float Chamber- Multiple Carburettors- Multiple Choke Carburettors - Carburettor Trouble - Car- burettor Icing - Air Cleaner and Silencer - Petrol Pump - Petrol Filters-Petrol Tank - Petrol Injection- Supercharging- Pollution 8 Cooling the Engine 104 Introduction- Air Cooling- Water Cooling- Comparison of Systems 9 Lubrication 113 The Purpose of Lubrication - Lubricating Oils - Additives - Splash Lubrication - Low-pressure Lubrication - High-pressure Lubrication - The Oil Pump - The Filter - The Pressure Gauge - The Breather - Oil Capacity 10 Engine Electrics 123 Introduction - Coil Ignition - Ignition Timing - Automatic Advance and Retard -The Sparking Plug-Suppression of Radio Interference - Alternative Ignition Systems - The Battery - The Dynamo- Voltage Control- The Cut-out Unit- The Alternator - The Starting System 11 Examples of Modem Engines 145 Introduction- The Hillman Imp - The Vauxhall Viva - The Jaguar 4·2 Litre- The Ford Cortina 12 'The Two-stroke Engine 154 The Two-stroke Cycle - Two-stroke Engine Design - Alternative Engine Forms- Two-stroke Crankcase- Two-stroke Cylinders- Two-stroke Pistons - Two-stroke Cylinder Heads - Two-stroke Lubrication - Two-stroke Ignition - A Two-stroke Car Engine; The Saab 13 Alternative Types of Power Unit 161 The Compression Ignition Engine - Combustion Chambers - Fuel Injection System - Two-stroke Compression Ignition Engines - Improving the Reciprocating Engine - The Free Piston Engine- The Gas Turbine - The Wankel Engine 14 The Complete Car and Basic Structure 170 Types of Car- The Typical Layout- Layout Variations- The Chassis Frame - Semi-unit Construction - Unit Construction -Unit Mounting 15 Suspension Systems 178 Introduction - Suspension Factors - Front Suspension - Rear Suspension - Springs - Coupled Suspension Systems - Hydro- lastic Suspension - Fully Coupled Suspension - Additional Sus- pension Control Springs - Dampers CONTENTS ix 16 Steering 199 Steering Principles - The Steering Linkage- The Steering Box­ Types of Steering Boxes - The Steering Wheel and Column - Power-assisted Steering 17 Wheels, Tyres and Brakes 210 Wheel Requirements - Pressed Steel Wheels - Wire Wheels - Cast Wheels - Wheel Bearings - The Purpose of Tyres - Tyre Construction - Radial-ply Tyres - Special Purpose Tyres - High Hysteresis Rubber- The Tyre Valve- Tyre Sections and Pressures - Tyre Wear - Wheel and Tyre Balancing - Spare Wheels - Braking Requirements - Types of Brakes - Drum Brakes- Disc Brakes- The Hydraulic System- Brake Shoes and Linings - Brake Testing - Power Brakes 18 The Clutch 236 The Purpose of the Clutch - The Principle of the Single Plate Clutch - The Modern Single Plate Clutch - The Clutch Plate - Clutch Operation - Multiplate Clutches - The Centrifugal Clutch - The Magnetic Clutch - The Fluid Coupling - The Torque Converter 19 The Gearbox 245 The Need for the Gearbox - Traction Principles - Gearing - Gearwheels - Gear Engagement - The Three-speed 'Crash' Gearbox - The Constant Mesh Gearbox - Synchromesh - Selecting and Holding Gears -The Gearbox Casting- Epicyclic Gearing - The Epicyclic Gearbox - The Electromagnetic Gear­ box - Overdrive - Automatic Gearboxes 20 The Drive from Gearbox to Road Wheels 267 Introduction - The Propeller Shaft - Universal Joints - The Final Drive Unit- The Rear Axle- The Differential Unit- Rear­ engined Cars - Front Wheel Drive - Four Wheel Drive - The Variable Pulley Belt Drive 21 The Body Structure 277 Modern Body Style - Body Construction - The Doors - Win- dows and Winders - Door Locks - The Roof- Anti-corrosion Treatment - Visibility - Windscreen Wipers - Windscreen Washers - Driving Mirrors - Seats - Stowage -Heating and Ventilation - Comfort and Safety- Driving Position and Con- trols - Instruments - Controls - Lamps - Direction Indicators - The Horn - Accessories - Wiring 22 Testing the Car 313 The Purpose of Tests - Laboratory Tests - Indicators - Measur­ ing Brake Horsepower - Flowmeters - Field Tests - Road Tests Index 319 Conversion Factors (Imperial to Metric Units) Length I inch = 25·4 mm I mm = 0·03937 in I foot = 0·3048 m 1m = 3·281 ft I yard = 0·9I44 m 1m = 1·094yd I mile = I·609 km 1 km = 0·6215 mile Area I in• = 6·452 em• 1 em• = 0·155 in' Volume and Capacity I in3 = 16·387 ems 1 ems = 0·06102 in8 1 gallon = 4·546 I 1 litre = 0·220 gal Mass 1 lb = 0·4536 kg 1 kg = 2·2046 lb 1 ton= 1016 kg I kg = 0·00098 ton Torque 1 lb ft = 0·138 kg m 1 kg m = 7-233 lbf ft Pressure 1 lb/in' = 703·07 kg/m' I kg/m2 = 0·00142 lb/in• 1 lbf/in2 = 68·95 m bar 1 m bar = 0·0145 lbf/in' Speed 1 m.p.h. = 1·609 km/h 1 km/h = 0·6215 m.p.h. I ft/min = 0·3048 m/min 1 m/min = 3·281 ft/min 1 ft/min = 0·00508 m/sec 1m/sec = I96·85 ft/min Acceleration I ft/sec• = 0·3048 m/sec• 1 m/sec' = 3·281 ft/sec• Consumption 1 m.p.g. = 0·354 km/1 1 km/1 = 2-825 m.p.g. 1 m.p.g.= 282/(1/100 km) 11/100 km = 282/m.p.g. Energy 1 Btu= 1·055 kJ 1 kJ = 0·948 Btu Power I horsepower = 745·7 W (i.e. J/sec) 1 kW = 1·341 h.p. = 0·7457kW Specific Energy I Btu/lb = 2326 J/kg 1 J/kg = 0·00043 Btu/lb .