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Lean-Burn Stratified Alcohol Fuels Engines of Power Density up to 475 kW/liter Featuring Super-Turbocharging, Rotary Valves, Direct Injection, and Jet Ignition
ISSN: 0148-7191, e-ISSN: 2688-3627
To be published on September 15, 2020 by SAE International in United States
The use of direct injection (DI) and jet ignition (JI) and assisted turbocharging has permitted to develop high efficiency, high power density, positive ignition (PI), lean-burn stratified, internal combustion engines (ICEs) able to deliver peak efficiency in excess of 50% and power density of 340 kW/liter at the 15,000 rpm revolution limiter working with overall λ=1.45 with gasoline. Starting from this experience, we numerically study the further improvements in power density that may be obtained by replacing poppet valves wit rotary valves, while also using mechanical rather than electric-assisted turbocharging. A numerical rotary valve ICE, that is adopting mechanically assisted turbocharging (super-turbocharging) is developed. Results of simulations for this novel ICE, having methanol as the working fuel, show the opportunity to achieve λ=1.45 power densities of 480 kW/liter, while also delivering an about constant torque, and a consequently nearly linear power curve, over an extremely wide range of speeds, up to 24,000 rpm. the paper proposes a numerical study of a high power density engine. The proposed engine design could be of interest to revive IndyCar racing, now suffering of a major technological gap vs. FIA F1 racing, with methanol as the fuel, or military unmanned aerial vehicles with gasoline as the fuel, for enhanced range, altitude, payload and maneuverability.