An Overview of Some Turbocharged Gasoline and Diesel Engine Automobiles

This paper makes an overview of published data on the performance, fuel economy, and emissions of some recently introduced turbocharged gasoline and diesel engine powered passenger cars. These vehicles are compared with models equipped with naturally aspirated engines of larger displacement and with comparable overall performance. The problems of the small turbocharger are discussed. Some data is provided on the efficiency degradation of small compressors as a function of blade tip clearances. Different magnitudes of fuel economy improvement can be obtained by applying the turbocharger to gasoline and diesel engines depending on the utilization of the increased power. The use of increased power is largely limited by the turbocharger inefficiency and acceleration lag. Solutions to these problems do not appear promising for the near term. Furthermore, power options continue to be offered by U.S. manufacturers with engines of increased displacement. In view of these considerations, it appears unlikely that any type of turbocharger will be applied to high volume production models manufactured by U.S. automakers in the near term.