This textbook offers a comprehensive review of tractor design fundamentals. Discussing more than hundred problems and including about six hundred international references, it offers a unique resource to advanced undergraduate and graduate students, researchers and also practical engineers, managers, test engineers, consultants and even old-timer fans. Tractors are the most important pieces of agricultural mechanization, hence a key factor of feeding the world. In order to address the educational needs of both less and more developed countries, the author included fundamentals of simple but proved designs for tractors with moderate technical levels, along with extensive information concerning modern, premium tractors. The broad technical content has been structured according to five technology levels, addressing all components. Relevant ISO standards are considered in all chapters. The book covers historical highlights, tractor project management (including cost management), traction mechanics, tires (including inflation control), belt ground drives, and ride dynamics. Further topics are: chassis design, diesel engines (with emission limits and installation instructions), all important types of transmissions, topics in machine element design, and human factors (health, safety, comfort). Moreover, the content covers tractor-implement management systems, in particular ISOBUS automation and hydraulic systems. Cumulative damage fundamentals and tractor load spectra are described and implemented for dimensioning and design verification. Fundamentals of energy efficiency are discussed for single tractor components and solutions to reduce the tractor CO2 footprint are suggested.

Agriculture has benefited considerably from the wide-scale use of tractors and associated implements. Tractors have developed along two, at times contradictory, design paths. The first of these has resulted in functional improvements to the vehicle, making it capable of im proved performance in the often harsh environmental conditions in which it is required to operate. For example, agricultural tires have improved the versatility of tractors by allowing them to operate at relatively high speeds on a variety of terrains, and hydraulics have provided for flexibility in controlling and operating implements. It can also be seen that these particular functional design improvements have contributed significantly to the second design pathway, that of ergon omics, and the human-machine interface. Recent stress on the working environment for the tractor operator has led to design improvements relative to tractor cabs, the placement and labeling of controls, etc. This text discusses those factors relevant to the design, selection, and operation of tractor-implement systems. The audience for which it is intended is undergraduate and graduate students of agricultural engineering studying power and machinery. However, the text is suf ficiently applied to have relevance for those extension personnel in volved with advising farmers on the selection and operation of tractor implement combinations. The tractor cannot be regarded in isolation from the implement, nor from the environment in which both the tractor and implement are ix x Preface working.

A link between machine functionality, operations, performance and decision making in the management of power sources and field operations were presented in this book. Depreciation and functional deviation of a machine from its original state at manufacture could put the life of a machine in danger of breakdown or obsolescence, which is counted a loss to any such organization or the entrepreneur. To avoid such losses, an understanding of machine systems functionality and a well organized maintenance programme designed to maintain, prevent or restore machine to near original state is required. Vocational training and entrepreneurship education in Nigeria's tertiary institutions has made possible a do-it-yourself skill acquisition in machine fault tracking, maintenance and repairs. A bimodal training programme packaged and presented in this book is all that is required for managerial decision making, maintenance and qualitative service delivery.

This thesis utilizes a terramechanics-based farm tractor model to predict machine performance. This model is used to reflect on tractor evolution throughout the last century and the physics-based principles that govern tractor performance. Insights from this model and reflection can help designers create new farm tractor embodiments, especially for markets where farming practices and industrial context differ significantly from those that shaped the conventional tractor's major evolutionary steps. It is shown how the small tractor evolved to its conventional modern form in in the early 1900s in USA pushed not only by suitability to domestic agriculture at the time but also efficiency in contemporary mass manufacturing and symbiosis with the burgeoning automotive industry. The farm tractor model as suggested in this thesis is proven to be in good agreement with published experimental data and historical standarized tractor testing. Inline drive wheels and mounting soil working implements between front and rear axles are identified as high potential design options for adapting the small tractor to modern emerging markets where draft animals are the dominant source of draft power.

This bulletin provides principles, practices and procedures for testing machines and also determines aspects of a machine's performance that can be evaluated. It is directed towards those involved in the evaluation of machinery, and primarily towards users on small farms. Evaluation of farm equipment may be appropriate at any stage in its development, from first prototype to batch and series production.