Motor Vehicle Science Part 1

Transcription

1 Motor Vehicle Science Part 1

2 Motor Vehicle Science Part 1 P. W. Kett LONDON NEW YORK CHAPMAN AND HALL

3 First published 1982 by Chapman and Hall Ud 11 New Fetter Lane, London EC4P 4EE Published in the USA by Chapman and Hall in association with Methuen, Ine. 733 Third Avenue, New York NY P. W. Kett Softcover reprint of the hardcover 1 st edition 1982 ISBN (cased) ISBN (paperback) This title is available in both hardbound and paperback editions. The paperback edition is sold subject to the condition that it shall not, by way of trade or otherwise, be lent, re-sold, 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. All rights reserved. No part of this book may be reprinted, or reproduced or utilized in any form or by any electronic, mechanical or other means, now known or hereafter invented, including photocopying and recording, or in any information storage and retrieval system, without permission in writing from the Publisher. British Library Cataloguing in Publication Data Library of Congress Cataloging in Publication Data Ket!, P. W. Ket!, P. W. Motor vehicle seienee. Motor vehicle seienee. Part 1 I. Automobiles - Design and eonstruetion Includes index. l. Tide I. Motor vehieles. l. Title TLl45 TLl46.K ISBN DOI / ISBN (ebook)

4 To my wife I dedicate this book. Her forbearance, help and understanding over the past two years made the book possible.

5 Contents Preface Nomenclature 1. Materials (AI) 1.1 Stress and strain 1.2 Hooke's Law and Young's Modulus 1.3 Testing of materials: load-extension graphs Exercises Heat 2.1 linear and cubical expansion (B2) Exercises Sensible heat and latent heat (B3) 2.3 Specific heat capacity 2.4 Boiling point of liquids Exercises Elementary thermodynamics (B4) Exercises Compression ratios (B5) Exercises Engine power and efficiency (B6) Exercises Internal combustion engine cycles 2.9 Imep, bmep and mechanical efficiency Exercises Engine torque and brake power 2.11 Fuel consumption and thermal efficiency Exercises Engine testing and characteristic curves 2.13 Conservation of energy 2.14 Indicated power and mechanical efficiency Exercises 2.8 Exercises 2.9 xi xiii

6 viii Contents 2.15 Fuel consumption and thermal efficiency 2.16 Ignition tests 2.17 Heat balance tests Exercises Fuels used in IC engines (B7) 3. Dynamics 3.1 Velocity and acceleration (C8) Exercises Free falling and projected bodies Exercises Angular and linear motion (C9) Exercises Friction and bearings (CI0) Exercises Clutches Exercises Brakes Exercises Lllbrication (011) 4.1 Principles of bearings and their uses 4.2 Ball and roller bearings 4.3 Properties of lubricating oils 5. Statics 5.1 Triangle and polygon offorces (E13) 5.2 Piston, connecting rod and cylinder wall forces 5.3 Torque at the crankshaft 5.4 Piston displacement 5.5 Wheel balance Exercises Principle of moments (EI4) 5.7 Centre of gravity Exercises Reaction of beam supports (EI5) 5.9 Bending moments and shearing forces Exercises Springs and torsion bars (EI6) Exercises Transmission and steering components (EI7) Exercises

7 Contents ix 6. Electricity (FI8) 6.1 The secondary cell 6.2 Battery developments Exercises Miscellaneous exercises 7.1 Materials 7.2 Heat 7.3 Dynamics 7.4 Statics Answers to Exercises Index The alpha-numeric code which appears after the entries refers to the TEe U77/413 and 415 Motor Vehicle Science II and III Model Programmes of Study.

8 Preface A motor vehicle technician has to attain high technological skills to enable him or her to diagnose faults and service modern transport vehicles and their components. Science is a branch of study concerned with the systematic investigation of observed facts, and forms an important foundation on which to build sound engineering practice. Such a background will stimulate personal development by increasing confidence and intellectual ability. This is the first of two books planned to cover the TEe U77/413 and 415 Motor Vehicle Science II and III Model programmes of study. Part 1 is intended to cover the requirements of Motor Vehicle Science II. The fundamental principles of engineering science have been applied to the motor vehicle in a systematic and progressive manner to enable the reader to follow most of the work on his or her initiative. The book is aimed mainly at the student who is attending a recognized college course leading to a Technician qualification. The importance of the college lecturer and his individual method of teaching the subject remains of prime importance to the student. The book is designed to become a valid source of information to assist the student both in and out of the classroom environment to attain his or her objective. Numerous fully worked and exercise examples are given. Plenty of practice in solving problems is an excellent way to gain knowledge of the subject, and improve confidence in preparation for an examination. The signs and symbols used in this book will be repeated where applicable in Part 2, thus the reader can become conversant with them and recognize their meaning immediately. All the SI symbols and abbreviations used are the official ones. Filby Norfolk P.W.K.

9 Nomenclature The following is a list of abbreviations and symbols used in the book. A a ACW BDC bhp BM bmep c CF CG CI CP CSA CV CW D d DOM DOR DP DVN DVR E e F f FR g GR h area (m2) acceleration (m/s2) anti-clockwise bottom dead centre brake horse power bending moment (N m) break mean effective pressure (N/m2) specific heat capacity (J/(kg 0C» or (J/(kg K» centrifugal force (N) centre of gravity compression ignition circular pitch cross-sectional area (m2) calorific or heat value (J/kg) clockwise diameter (m) diameter (m) or relative density (no units) direction of motion direction of rotation diametrical pitch driven driver Young's Modulus (Modulus of Elasticity) (N/m2) or equilibrant force (N) tensile or compressive strain, or transmission efficiency force (N) stress (N/m2) or final drive ratio force ratio (or mechanical advantage) acceleration due to gravity (usually taken as 9.81 m/s2) gear ratio height (m) or hub reduction ratio

10 xiv Nomenclature hp ihp imep L I LofP LCV m mc ME MP MR N n NTP(or STP) p p PC PCD R r S SF SFC STP TE T t TDC u V v wc W(orw) x Greek letters a 11 p. horse power indicated horse power indicated mean effective pressure (Pm) (N/m2, Pa) length (m) latent heat (J/kg) limit of proportionality lower calorific value mass (kg) master cylinder mechanical efficiency (%) module pitch movement ratio revolutions per minute (rev/min) number (e.g. pistons) or reduction ratio normal (or standard) temperature and pressure power(w) pressure (Pa, N/m2) pitch circle pitch circle diameter (m) reaction (or resultant force) (N) or radius (m) compression ratio (CR) distance or displacement (m) or piston speed (m/s) shearing force (N) specific fuel consuniption (kg/(kw h) or l/(kw h)) see NTP tractive effort temperature (OC, K) or torque (N m) or number of gear teeth time (s, h) top dead centre initial velocity (m/s) volume (m3) or velocity (m/s) velocity or fmal velocity (m/s) wheel cylinder (hydraulic) weight or load (kg) extension (m) coefficient of linear expansion (per C) efficiency (%) coefficient of friction

11 Nomenclature xv p density </>,8 angles (rad, 0) angular velocity (rad/s) w Subscripts B big end b bearing or braking c connecting rod or clearance or crown D drag d drum e expanded F front f fusion or friction I inlet indicated or inner L leading m mean or mechancial N normal or nearside 0 outlet or offside 0 outer p piston R road or rear r radial s swept or servo or shoe T trailing t total or tangential w cylinder wall