Internal Combustion Engines Fundamentals

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McGraw-Hill Series in Mechanical EngineeringJack P. Holman, Southern Methodist University Consulting Editor Anderson: Modern Compressible Flow: With Historical Perspective Dieter: Engineering Design: A Materials and Processing Approach Eckert and Drake: Analysis of Heat and Mars Transfer Heywood: Internal Combwtion Engine Fundamentals H i m : Turbulence,2/e Hutton: Applied Mechanical Vibrations Juvinall: Engineering Considerations of Stress, Strain, and Strength Kane and Levinson: Dynamics: Theory and Applications Kays and Crawford: Convective Heat and Mass Transfr Mutin: Kinematics and Dynamics of Machines Pklan: Dynamics of Machinery Pbelan: Fundamentals of Mechanical Design, 3/e Pierce: Acoustics: An Introduction to Its Physical Principles and Applications Raven: Automatic Control Engineering, 4/e Rosenberg aod Karnopp: Introduction to Physics Schlichting: Boundary-Layer Theory, 7/e Shames: Mechanics of Fluiak, 2/e Shigley: Kinematic Analysis of Mechanisms, 2/e Sbigley and Mitchell: Mechanical Engineering Design, 4/e Sbigley and Uicker: Theory of Machines and Mechanisms Stoecker and Jones: Refrigeration and Air Conditioning, 2/e Vanderplaats: Numerical Optimization Techniquesfor Engineering Design: With Applications

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INTERNAL COMBUSTION ENGINEJohn B.LHeywoodProfessor of Mechanical Engineering Director, Sloan Automotive Laboratory Massachusetts Institute of Technology

Xnderung nur iiberFechbibliothek BFV21 (S!V

McGraw-Hill, Inc. New York St. Louis San Francisco Auckland Bogoti Caracas Lisbon London Madrid Mexico City Milan Montreal New Delhi San Juan Singapore Sydney Tokyo Toronto

INTERNAL COMBUSTION ENGINE FUNDAMENTALSThis book was set in Times Roman. The editors were Anne Duffy and John M. M o m s ; the designer was Joan E. O'Connor; the production supervisor was Denise L. Puryear. New drawings were done by ANCO. Project Supervision was done by Santype International Ltd. R. R. Donnelley & Sons Company was printer and binder.See acknowledgements on page xxi.

ABOUT THE AUTHOR

Copyright 0 1988 by McGraw-Hill, Inc. All rights rese~ed. Printed in the United States of America. Except as permitted under the United States Copyright Act of 1976, no part of this publication may be reproduced or distributed in any form or by any means, or stored in a data base or retrieval system, without the prior written permission of the publisher.

ISBN

0-07-028637-X

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Library o fC o n g r e s s Cataloging-iP.PublicationDataHeywood, John B. Internal combustion engine fundamentals. (McGraw-Hill series in mechanical engineering) Bibliography: p. Includes index. I. Internal combustion engines. I. Title. 11. Series. TJ755.H45 1988 621.43 87-15251

This book is printed on acid-free paper.

Dr. John B. Heywood received the Ph.D. degree in mechanical engineering from the Massachusetts Institute of Technology in 1965. Following an additional postdoctoral year of research at MIT, he worked as a research officer at the Central Electricity Generating Board's Research Laboratory in England on magnetohydrodynamic power generation. In 1968 he joined the faculty at MIT where he is Professor of Mechanical Engineering. At MIT he is Director of the Sloan Automotive Laboratory. He is currently Head of the Fluid and Thermal Science Division of the Mechanical Engineering Department, and the Transportation Energy Program Director in the MIT Energy Laboratory. He is faculty advisor to the MIT Sports Car Club. Professor Heywood's teaching and research interests lie in the areas of thermodynamics, combustion, energy, power, and propulsion. During the past two decades, his research activities have centered on the operating characteristics and fuels requirements of automotive and aircraft engines. A major emphasis has been on computer models which predict the performance, efficiency, and emissions of spark-ignition, diesel, and gas turbine engines; and in carrying out experiments to develop and validate these models. He is also actively involved in technology assessments and policy studies related to automotive engines, automobile fuel utilization, and the control of air pollution. He consults frequently in &he automotive and petroleum industries, and for the U.S. Government. . S . His extensive research in the field of eogines has been supported by the U Army, Department of Energy, Environmental Protection Agency, NASA, National Science Foundation, automobile and diesel engine manufacturers, and petroleum companies. He has presented or published over a hundred papers on

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ABOUT THE A U T H O R

his research in technical conferences and journals. He has co-authored two previous books: Open-Cycle MHD Power Generation published by Pergamon Press in 1969 and The Automobile and the Regulation of Its Impact on the Environment published by University of Oklahoma Press in 1975. He is a member of the American Society of Mechanical Engineers, an associf ate fellow of the American Institute of Aeronautics and Astronautics, a fellow o the British Institution of Mechanical Engineers, and in 1982 was elected a Fellow of the U.S. Society of Automotive Engineers for his technical contributions to automotive engineering. He is a member of the editorial boards of the journals Progress in Energy and Combustion Science and the International Journal of Vehicle Design. His research publications on internal combustion engines, power generation, and gas turbine combustion have won numerous awards. He was awarded the Ayreton Premium in 1969 by the British Institution of Electrical Engineers. Professor Heywood received a Ralph R. Teetor Award as an outstanding young engineering educator from the Society of Automotive Engineers in 1971. He has twice been the recipient of an SAE Arch T. Colwell Merit Award for an outstanding technical publication (1973 and 1981). He received SAE's Horning Memorial Award for the best paper on engines and fuels in 1984. In 1984 he received the Sc.D. degree from Cambridge University for his published contributions to engineering research. He was selected as the 1986 American Society of Mechanical Engineers Freeman Scholar for a major review of "Fluid Motion within the Cylinder of Internal Combustion Engines."

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THISBooK IS DEDICATED TO MY FATHER, Harold Heywood :.

I have followed many of the paths he took.

vii

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CONTENTS

Preface-

xvii xxiii

Commonly Used Symbols, Subscripts, and AbbreviationsIntroduction and Historical Perspective Engine Classifiytions Engine Operating Cycles Engine Components Spark-Ignition Engine Operation Examples of Spark-Ignition Engines Compression-Ignition Engine Operation Examples of Diesel Engines Stratified-ChargeEngines

Chapter 1 Engine Types and Their Operation1.1 1.2

1.31.4

1.51.6 1.7

1.81.9

Chapter 2 Engine Design and Operating Parameters2.1 2.2

232.4 2.5 2.6 2.7 2.8 2.9

Important Engine Characteristics Geometrical Properties of Reciprocating Engines Brake Torque and Power Indicated Work Per Cycle Mechanical Efficiency Road-Load Power Mean Effective Pressure Specific Fuel Consumption and Efficiency Air/Fuel and Fuel/Air Ratios

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CONTENTS

2.10 2.11 2.12 2.13 2.14 2.15

Volumetric Efficiency Engine Specific Weight and Specific Volume Correction Factors for Power and Volumetric Efficiency Specific Emissions and Emissions Index Relationships between Performance Parameters Engine Design and Performance Data

Chapter 5 Ideal Models of Engine Cycles5.1 5.2 5.3 5.4

Chapter 3 Thermochemistry of Fuel-Air Mixtures3.1 3.2 3.3 3.4 3.5

Characterization of Flames Ideal Gas Model Composition of Air and Fuels Combustion Stoichiometry The First Law of Thermodynamics and Combustion 3.5.1 Energy and Enthalpy Balances 3.5.2 Enthalpies of Formation 3.5.3 Heating Values 3.5.4 Adiabatic Combustion Processes 3.5.5 Combustion Efiency of an Internal Combustion Engine The Second Law of Thermodynamics Applied to Combustion 3.6.1 Entropy 3.6.2 Maximum Work from an Internal Combustion Engine and Efficiency Chemically Reacting Gas Mixtures 3.7.1 Chemical Equilibrium 3.7.2 Chemical Reaction Rates

5.8

Introduction Ideal Models of Engine Processes Thermodynamic Relations for Engine Processes Cycle Analysis with Ideal Gas Working Fluid with c, and Constant 5.4.1 Constant-Volume Cycle 5.4.2 Limited- and Constant-Pressure Cycles 5.4.3 Cycle Comparison Fuel-Air Cycle Analysis 5.5.1 SI Engine Cycle Simulation 5.5.2 CI Engine Cycle Simulation 5.5.3 Results of Cycle Calculations Overexpanded Engine Cycles Availability Analysis of Engine Processes 5.7.1 Availability Relationships 5.7.2 Entropy Changes in Ideal Cycles 5.7.3 Availability Analysis of Ideal Cycles 5.7.4 Effect of Equivalence Ratio Comparison with Real Engine Cycles

Chapter 6 Gas Exchange Processes6.1 6.2

Chapter 4 Properties of Working Fluids4.1 4.2 4.3 4.4 4.5

Introduction Unburned Mixture Composition Gas Property Relationships A Simple Analytic Ideal Gas Model Thermodynamic Charts 4.5.1 Unburned Mixture Charts 4.5.2 Burned Mixture Charts 4.5.3 Relation between Unburned and Burned Mixture Charts Tables of Properties and Composition Computer Routines for Property and Composition Calculations 4.7.1 Unburned Mixtures 4.7.2 Burned Mixtures Transport Properties Exhaust Gas Composition 4.9.1 Species Concentration Data 4.9.2 Equivalence Ratio Determination from Exhaust Gas Constituents 4.9.3 Effects of Fuel/Air Ratio Nonuniformity 4.9.4 Combustion Inefficiency

6.4 6.5 6.6

6.7 6.8

Inlet and Exhaust Processes in the Four-Stroke Cycle Volumetric Efficiency 6.2.1 Quasi-Static Effects 6.2.2 Combined Quasi-Static and Dynamic Ekects 'iming 6.2.3 Variation with Speed. and Valve Area, Lift, and ' I Flow Through Valves 6.3.1 Poppet Valve Ge