Acceleration of a Passenger Car Powered by A Fixed-Geometry Single-Shaft Gas Turbine Engine

Concern over exhaust emissions has revived interest in the gas turbine as a powerplant for passenger cars, and concern over cost has stimulated interest in the single-shaft version of this engine. A novel transmission is needed to compensate for the inherently poor output characteristics of the single-shaft engine. The rated power and response time of the engine and the efficiency and power split of the transmission are shown to be the primary parameters influencing vehicle acceleration. Some factors affecting engine response time are reviewed. Transmission parameters are studied by considering standing-start accelerations of an automobile powered by a fixed-geometry single-shaft engine using versions of three of the many types of possible transmissions. For the combinations considered, the fixed-geometry single-shaft engine cannot easily provide vehicle performance matching that of the traditional two-shaft turbine engine, if both start with the compressor idling at half rated speed. Higher idle speed improves engine acceleration but increases idle fuel consumption. Any cost advantage realized through selection of a single-shaft engine must be balanced against the cost of the transmission chosen to accommodate engine output characteristics.