Title: Development and characterisation of small-scale rotary engines

Authors: S. Bennett Sprague, Sang-Won Park, David C. Walther, Albert P. Pisano, A. Carlos Fernandez-Pello

Addresses: Department of Mechanical Engineering, University of California at Berkeley, Berkeley, CA 94720-1740, USA. ' Department of Mechanical Engineering, University of California at Berkeley, Berkeley, CA 94720-1740, USA. ' Department of Mechanical Engineering, University of California at Berkeley, Berkeley, CA 94720-1740, USA. ' Department of Mechanical Engineering, University of California at Berkeley, Berkeley, CA 94720-1740, USA. ' Department of Mechanical Engineering, University of California at Berkeley, Berkeley, CA 94720-1740, USA

Abstract: This paper describes the development and characterisation of small-scale rotary engines with displacements in the range of 78–1500 mm³ for portable applications in the range of 10–200 W of power output. Small-scale combustion engines present a number of research challenges including manufacturing tolerances, sealing, thermal management, ignition, combustion efficiency and porting. Four engines have been characterised using a custom test bench and show an increase in performance due to design changes that mitigate the challenges associated with small-scale engines. The volumetric power density has been increased from 11 W/cm³ in a 348 mm³ engine operating with a supercharged hydrogen/air mixture to 22 W/cm³ in a 1500 mm³ engine operating with naturally aspirated liquid hydrocarbon fuel. The thermal efficiency has also been increased from 0.2 to 4%. Continued improvements in sealing, thermal management, combustion efficiency and friction reduction will allow further increases in engine performance.

Keywords: small-scale rotary engines; meso-scale combustion; portable power; manufacturing tolerances; sealing; thermal management; ignition; combustion efficiency; porting; friction reduction; engine performance.

DOI: 10.1504/IJAP.2007.013016

International Journal of Alternative Propulsion, 2007 Vol.1 No.2/3, pp.275 - 293

Available online: 03 Apr 2007 *

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