Engineering Principles of Agricultural Machines 2nd Edition Ajit K. Srivastava Michigan State University Carroll E. Goering University of Illinois Roger P. Rohrbach North Carolina State University Dennis R. Buckmaster The Pennsylvania State University Copyright  2006 by the American Society of Agricultural and Biological Engineers All rights reserved. ASABE is an educational and scientific organization dedicated to the advancement of engineering applicable to agricultural, food, and biological systems. Editing by Peg McCann Cover design by Melissa Miller Production assistance by Patricia Howard and Marcia Stults McCavit Cover photo of a Massey Ferguson combine courtesy of AGCO Corporation. This book may not be reproduced in whole or in part by any means without the permission of the publisher. For information, contact the American Society of Agricultural and Biological Engineers 2950 Niles Road, St. Joseph, MI 49085-9659 USA Phone: 269-429-0300 Fax: 269-429-3852 E-mail: [email protected] Library of Congress Card Number (LCCN) 2005937948 International Standard Book Number (ISBN) 1-892769-50-6 ASAE Publication 801M0206 The American Society of Agricultural and Biological Engineers is not responsible for the statements and opinions advanced in its meetings or printed in its publications. They represent the views of the individuals to whom they are credited and are not binding on the Society as a whole. PREFACE We are pleased to offer the second edition of the textbook Engineering Principles of Agricultural Machines. To arrive at the revisions in the second edition, we called some instructors of the first edition and conducted lengthy phone interviews to seek their thoughts and suggestions for revisions. We interviewed Dr. Dennis Buckmaster of Penn State University, Dr. Dan Humburg of South Dakota State University, Dr. Lei Tian of the University of Illinois, and Dr. Ranal Taylor of Kansas State University. Based on their input we prepared a survey form listing the many changes suggested. The survey forms were sent to all instructors, in the U.S. and abroad, who were using the textbook. We compiled the responses and rated each suggestion. We also held a user forum during the 2005 ASABE conference in Tampa, Florida to share the results of our survey and to seek additional input. Items receiving a 3 or higher score on a 5- point scale were marked for inclusion in the revised edition. The changes can be divided in four categories. These are: reorganization of chap- ters into shorter modules to allow instructors greater flexibility in selecting topics to match their needs; the addition of a new chapter on agricultural information systems in response to the growth in precision agriculture technology since the first edition; addition of simulation problems; and adding a supplemental CD that includes a spreadsheet and many simulations. We feel the CD will add a new dimension to student learning and give them the opportunity to develop a deeper understanding of the process under study as affected by the various system parameters. We are very pleased that Dr. Dennis Buckmaster has joined the list of authors. Dennis has been an avid user of the textbook and has developed much supplemental simulation material during the course of teaching principles of agricultural machines at Penn State University. We have included much of his material in the accompanying CD. Dennis also revised the chapter on hay and forage harvesting. Finally, we would like to thank the many people who have been helpful in the process of preparing this edition. We thank Monte Dickson for providing a thorough review of the new chapter on agricultural information systems (Chapter 6). We would also like to acknowledge Frank Zoz for letting us include his traction prediction model in the CD, and Al Hanson for letting us use his engine simulator in the CD. As always, we welcome your feedback and suggestions for improvement. Please feel free to contact any of us. Additions and changes will be posted to the ASABE Technical Library at http://asae.frymulti.com/toc.asp (scroll down to the listing of textbooks). For specific questions we ask that you direct your inquiries to Ajit Srivastava for Chapters 1, 4, 8, 10, 12, and 14; to Carroll Goering for Chapters 2, 3, 5, 6, 7, 9, and 15; to Roger Rohrbach for Chapter 13; and to Dennis Buckmaster for Chapter 11 and the accompanying CD. Ajit Srivastava ([email protected]) Carroll Goering ([email protected]) Roger Rohrbach ([email protected]) Dennis Buckmaster ([email protected]) The authors wish to dedicate this edition to their wives Barbara Srivastava, Carol Goering, Jeanette Rohrbach, and Corinne Buckmaster for their unwavering support and encouragement throughout our lives. CONTENTS Chapter 1 Agricultural Mechanization and Some Methods of Study 1 Introduction..............................................................................................................1 1.1 History of Mechanized Agriculture.................................................................1 1.2 Farming Operations and Related Machines...................................................3 1.3 Functional Analysis of Agricultural Machines...............................................4 1.3.1 Basic processes of agricultural machines.................................................5 1.3.2 Process diagrams......................................................................................6 1.4 Dimensional Analysis.....................................................................................7 1.4.1 Scope........................................................................................................7 1.4.2 Physical dimensions.................................................................................7 1.4.3 Units of measurement..............................................................................8 1.4.4 Developing a prediction equation............................................................9 1.4.5 Buckingham’s Theorem.........................................................................10 1.4.6 Systematic calculation of the dimensionless products.............................12 1.4.7 Transformation of dimensionless products............................................13 Problems.................................................................................................................14 Chapter 2 Engine Power for Agricultural Machines 15 Introduction............................................................................................................15 2.1 The power in fuel..........................................................................................15 2.2 Combustion...................................................................................................16 2.2.1 Combustion chemistry...........................................................................16 2.2.2 Energy release in combustion................................................................19 2.3 Thermodynamic limits to Engine Performance............................................21 2.4 Heat Losses and Power at the Pistons..........................................................25 2.5 Mechanical Losses and Power at the Flywheel.............................................26 2.6 Engine Torque and Efficient Engine Loading..............................................28 2.7 Control of Engine Speed...............................................................................29 2.8 Engine performance simulator.....................................................................33 2.9 Turbocharging and Intercooling Engines.....................................................35 2.9.1 Operation of turbochargers....................................................................36 2.9.2 Intercoolers............................................................................................39 2.9.3 Turbocharging and intercooling for versatility......................................39 Problems.................................................................................................................41 Simulation Problems...............................................................................................43 Chapter 3 Electrical Power for Agricultural Machines 45 Introduction............................................................................................................45 3.1 Motor Components........................................................................................45 3.2 Motor Classifications....................................................................................46 3.3 Principles of Operation Of Induction Motors...............................................47 3.4 Types of Single-Phase Induction Motors.....................................................49 3.4.1 Split-phase induction motors..................................................................49 3.4.2 Capacitor-start, induction-run motors....................................................50 3.4.3 Two-value-capacitor, induction-run motors...........................................52 3.4.4 Repulsion-start, induction-run motors....................................................52 3.5 Three-Phase Induction Motors.....................................................................53 3.6 Dual-Voltage Motors....................................................................................54 3.7 Torque-Speed Characteristics of Induction Motors.......................................56 3.8 Motor Nameplate Information.....................................................................57 3.9 Motor Starters...............................................................................................59 3.10 Motor Enclosures..........................................................................................59 3.11 Variable- Speed Electric Motors..................................................................59 3.12 Motor Efficiency...........................................................................................60 Problems.................................................................................................................61 Simulation Problems...............................................................................................63 Chapter 4 Mechanical Power Transmission 65 Introduction............................................................................................................65 4.1 V-Belt Drives................................................................................................65 4.1.1 V-belt types and standardization............................................................66 4.1.2 V-belt drive geometry............................................................................67 4.1.3 Kinematics of V-belt drives...................................................................68 4.1.4 Mechanics of V-belt drives....................................................................69 4.1.5 Stresses and service life.........................................................................72 4.1.6 Variable-speed V-belt drives..................................................................74 4.1.7 V-belt drive design.................................................................................76 4.2 Chain Drives.................................................................................................76 4.2.1 Types of chains and standardization......................................................76 4.2.2 Geometry of chain drives.......................................................................79 4.2.3 Kinematics of chain drives.....................................................................79 4.2.4 Design of chain drives............................................................................82 4.3 Power-Take-Off Drives.................................................................................83 4.4 Overload Safety Devices...............................................................................87 4.4.1 Shear devices.........................................................................................87 4.4.2 Jump clutch devices...............................................................................88 4.4.3 Friction devices......................................................................................89 Problems.................................................................................................................90 Chapter 5 Fluid power, mechatronics, and control 91 Introduction............................................................................................................91 5.1 Basic Principles and Elements Of Fluid Power............................................91 5.2 Pumps............................................................................................................92 5.3 Valves...........................................................................................................96 5.3.1 Pressure control valves...........................................................................96 5.3.2 Volume control valves...........................................................................98 5.3.3 Directional control valves......................................................................99 5.4 Actuators.....................................................................................................102 5.4.1 Hydraulic motors.................................................................................102 5.4.2 Hydraulic cylinders..............................................................................102 5.5 Reservoirs, Fluids, Filters, and Lines.........................................................104 5.6 Types of Fluid Power Systems...................................................................107 5.6.1 Open-center systems............................................................................107 5.6.2 Pressure-compensated systems............................................................109 5.6.3 Load-sensing systems..........................................................................109 5.7 Pressure Transients......................................................................................111 5.8 Hydrostatic Transmissions..........................................................................112 5.9 Mechatronics and System Control.............................................................114 5.9.1 An introduction to mechatronics..........................................................114 5.9.2 System control.....................................................................................115 Problems...............................................................................................................117 Simulation Problems.............................................................................................121 Chapter 6 Precision agriculture 123 Introduction..........................................................................................................123 6.1 Sensors........................................................................................................124 6.1.1 Sensor types.........................................................................................124 6.1.2 Sensor applications..............................................................................124 6.1.3 Advanced sensors.................................................................................124 6.2 Global Positioning System..........................................................................125 6.2.1 GPS for civilian use.............................................................................125 6.2.2 Military GPS........................................................................................125 6.2.3 Differential GPS...................................................................................125 6.2.4 Carrier-phase GPS...............................................................................126 6.2.5 Real-time kinematic GPS.....................................................................126 6.2.6 Accuracy measures..............................................................................126 6.2.7 Coordinate transformation...................................................................127 6.3 Geographic Information System.................................................................130 6.3.1 Data input to a FIS...............................................................................130 6.3.2 Map coordination.................................................................................131 6.3.3 Data analysis in the FIS.......................................................................133 6.3.4 Data persistence...................................................................................133 6.4 Variable Rate Applications.........................................................................133 6.4.1 Approaches..........................................................................................133 6.4.2 Applications.........................................................................................134 6.4.3 Application resolution..........................................................................134 6.4.4 Control systems....................................................................................134 6.4.5 Automatic guidance.............................................................................135 6.5 Controller Area Networks...........................................................................135 Problems...............................................................................................................137 Chapter 7 Tractor Hitching, Traction, and Testing 139 Introduction..........................................................................................................139 7.1 Hitching Systems........................................................................................139 7.1.1 Principles of hitching...........................................................................139 7.1.2 Types of hitches...................................................................................139 7.1.3 Hitching and weight transfer................................................................142 7.1.4 Control of hitches.................................................................................144 7.2 Tires and Traction.......................................................................................144 7.2.1 Basic tire design...................................................................................146 7.2.2 Traction models...................................................................................149 7.2.3 Traction predictor spreadsheet.............................................................153 7.3 Soil Compaction..........................................................................................154 7.4 Traction Aids...............................................................................................155 7.5 Tractor Testing............................................................................................156 7.5.1 Basic principles of tractor testing.........................................................156 7.5.2 Official tractor tests..............................................................................158 Problems...............................................................................................................165 Simulation Problems.............................................................................................166 Chapter 8 Soil Tillage 169 Introduction..........................................................................................................169 8.1 Tillage Methods and Equipment................................................................169 8.1.1 Primary tillage in conventional tillage systems....................................170 8.1.2 Secondary tillage in conventional tillage systems................................179 8.1.3 Tillage in conservation tillage systems................................................184 8.2 Mechanics of Tillage Tools.........................................................................185 8.2.1 Soil texture...........................................................................................185 8.2.2 Physical properties of soils..................................................................187 8.2.3 Mechanical properties of soils.............................................................189 8.2.4 Mechanics of a simple tillage tool.......................................................200 8.3 Performance of Tillage Implements...........................................................207 8.3.1 Moldboard plows.................................................................................207 8.3.2 Disk implements..................................................................................209 8.3.3 Cultivators............................................................................................211 8.3.4 Rotary tillers.........................................................................................214 8.4 Hitching of Tillage Implements.................................................................215 8.4.1 Forces on tillage tools..........................................................................215 8.4.2 Pull-type implements...........................................................................221 8.4.3 Mounted implements............................................................................226 Problems...............................................................................................................229 Chapter 9 Crop Planting 231 Introduction..........................................................................................................231 9.1 Methods and Equipment.............................................................................231 9.1.1 Broadcast seeding................................................................................231 9.1.2 Drilling.................................................................................................232 9.1.3 Precision planting.................................................................................233 9.1.4 Transplanting.......................................................................................234 9.2 Functional Processes...................................................................................235 9.2.1 Seed metering.......................................................................................235 9.2.2 Seed transport.......................................................................................245 9.2.3 Furrow opening and covering..............................................................255 9.2.4 Transplanting.......................................................................................258 9.3 Evaluating Planter and Transplanter Performance......................................262 9.3.1 Broadcast seeders.................................................................................262 9.3.2 Drills....................................................................................................264 9.3.3 Precision planters.................................................................................264 9.3.4 Transplanters........................................................................................265 Problems...............................................................................................................265 Chapter 10 Chemical Application 269 Introduction..........................................................................................................269 10.1 Application of Granular Chemicals............................................................269 10.1.1 Methods for application of granular chemicals....................................270 10.1.2 Equipment for application of granular chemicals................................270 10.1.3 Functional processes of granular chemical applications.....................273 10.2 Application of Liquid Chemicals...............................................................280 10.2.1 Methods for application of liquid chemicals........................................280 10.2.2 Equipment for application of liquid chemicals....................................280 10.2.3 Functional processes of applying liquid chemicals..............................286 10.3 Performance Evaluation..............................................................................310 10.3.1 Uniformity of coverage of granular chemical application..................310 10.3.2 Calibration of fertilizer spreaders.........................................................312 10.3.3 Liquid chemical application.................................................................315 10.3.4 Sprayer calibration...............................................................................321 Problems...............................................................................................................322 Chapter 11 Hay and Forage Harvesting 325 Introduction..........................................................................................................325 11.1 Methods and Equipment.............................................................................325 11.2 Functional Processes...................................................................................331 11.2.1 Cutting mechanics and plant structure.................................................331 11.2.2 Cutting and chopping...........................................................................343 11.2.3 Curing and preservation of forage........................................................370 11.2.4 Windrowing.........................................................................................374 11.2.5 Baling...................................................................................................380 11.3 Performance Evaluation..............................................................................392 Problems...............................................................................................................395 Chapter 12 Grain Harvesting 403 Introduction..........................................................................................................403 12.1 Methods and Equipment.............................................................................403 12.1.1 Direct harvesting..................................................................................403 12.1.2 Cutting and windrowing.......................................................................408 12.2 Functional Processes...................................................................................409 12.2.1 Gathering, cutting, pickup, and feeding...............................................410 12.2.2 Threshing.............................................................................................415 12.2.3 Separation............................................................................................420 12.2.4 Cleaning...............................................................................................427