case for single-shaft gas turbines
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\ single-shaft gas turbine, mated to an tely-variable transmission, would have a Der of advantages over a two-shaft, )ower turbine for vehicle applications. If ir turbine inlet temperatures become ple at a low cost, the gains could offset asses derived from the infinitely variable mission, and this could pave the way for nple, low-cost, single-shaft turbine en
ese comments were included in a paper Or. A. F. McLean of the Ford Motor pany, Dearborn, USA, read earlier this at a symposium on gas-turbine design sored by the internal combustion engines p of the Institution of Mechanical Enars, at Warwick University. The title of McLean's paper was "The case for singlet vehicular gas turbine".
ii-load fuel economy, Mr. McLean point ed out, could be improved in the case of the single-shaft turbine by employing it in conjunction with a torque converter, the stator vanes of which could be varied. This could be compared with varying the power-turbine nozzles of a two-shaft gas turbine to increase the part-load turbine inlet temperature.
Moreover, locking-up the overrunning clutch of the torque converter would allow the compressor to act as a retarder and the braking energy would be dissipated in the engine exhaustigases. In this way it would be possible to provide a maximum braking capability equivalent to 150 per cent of the rated power output.
While the specific fuel consumptions of the single-shaft turbine would be lower than those of the two-shaft type because of converter inefficiency, operating temperatures could be controlled in the interests of good
part-load specific fuel consumption. Fullthrottle torque characteristics and compressor spool acceleration times would be comparable; simplified and more symmetrical packaging would favour the use of high-temperature ceramic-structures. Also air cooling would be facilitated by mounting a singleor twostage turbine on the same shaft as the corn; pressor if cooling were later required to caterfor high temperatures; the cost of the power plant could possibly be reduced; separation of the engine from the torque converter would facilitate development work.