American Scientist

Vol. 61, No. 3 (May–June 1973)

ALTERNATIVES TO THE INTERNAL COMBUSTION ENGINE: Impacts on Environmental Quality. Robert U. Ayres and Richard P. McKenna. 324 pp. Johns Hopkins University Press, 1972. $12.

The internal combustion, or more correctly spark-ignition, engine has reigned supreme for sixty-five years. Its dominant position as the automotive power plant is now under increasing attack by environmentalists, politicians, and technologists for the problems its success has created. The ground rules under which this engine was developed are now being changed by regulation and resource depletion. Can the internal combustion engine survive these pressures in anything like its present form?

This book, which examines the technological aspects of this question, is for the reader who wants a detailed review of the operating principles and performance characteristics of the current internal combustion engine and its potential alternatives. It is not an extensive evaluation of automobile environmental effects as its subtitle implies. Nor is the book for the casual reader who wants a quick answer on which engine is going to win out. The book presents a useful and careful analysis of the advantages and disadvantages of the different types of automotive engine now being developed.

The first part summarizes briefly the role of the automobile in our transportation system, the emission characteristics of current automobile engines, and the air pollution problems which result. The second part, the bulk of the book, examines the technology of existing and potential alternative automotive power plants. The requirements of the vehicle and its use which these power plants must satisfy are described, and the basic thermodynamics of energy conversion reviewed. The performance characteristics of the current spark ignition engine, alternative types of spark ignition engines, automotive gas turbines, Rankine, Stirling, and Brayton cycle engines, electric and hybrid vehicles are all examined in turn. Part 2 concludes with a comparison of the performance and costs of these different engines. The authors conclude that the current engine is low on initial cost, moderate on fuel costs, and poor on maintenance costs relative to its competitors.

The book ends with a short section on the potential social and economic impact of an alternative automotive engine technology. The magnitude of this impact is the real factor which will determine whether the day of the current internal combustion engine is over. The technical evaluation of alternatives which this book ably provides is a starting point for assessing this broader policy issue. —John B. Heywood, Engineering, Massachusetts Institute of Technology