SuperGen on Ultraboost: Variable-Speed Centrifugal Supercharging as an Enabling Technology for Extreme Engine Downsizing

• DOI: 10.4271/2015-01-1282
• Publication Date: 2015-04-14T00:55:15Z
• Authors: J.W.G. Turner; A. Popplewell; D.J. Marshall; T.R. Johnson; L. Barker; J. King; J. Martin; A.G.J. Lewis; S. Akehurst; C.J. Brace; C.D. Copeland
• Keywords: Naturally aspirated engine; Mean effective pressure; Engine control unit; Overall pressure ratio

The paper discusses investigations into improving the full-load and transient performance of Ultraboost extreme downsizing engine by application SuperGen variable-speed centrifugal supercharger. Since its output stage speed is decoupled from that crankshaft, potentially especially attractive in a compound pressure-charging system. Such systems typically comprise turbocharger, which used as main charging device, compounded at lower charge mass flow rates supercharger second boosting stage. Because variable drive ratio, can be blended out continuously to provide seamless driveability, opposed alternative clutched, single-drive-ratio positive-displacement device. In this respect operation very similar an electrically-driven compressor, although it voltage agnostic supply other hybrid functionality, too. work reported here prototype unit was tested on demonstrator compared originally-specified This has previously been described detail represents 60% factor versus 5.0 litre naturally-aspirated V8, ‘standard’ baseline combination turbocharger found earlier limitation achieving full low speed. improvement area where cannot generate required boost itself reported. response combined system also presented, together with part-load fuel economy data several load points. Finally, for vehicle modelling showing more-efficient high-pressure bring further benefits extremely-downsized applications.