Mathematical Model of Two-Stage Turbocharging Gasoline Engine Propeller Propulsion System and Analysis of Its Flying Characteristic

A flying characteristic simulation method was studied for two-stage turbocharging compression ignition (CI) engine propeller propulsion system, intended for medium/high altitude low-speed long-endurance multirole aerial vehicle systems at 10–20 km high. Introducing the simulation method for gas turbine engine with component models, based upon component maps or algebraic equations, this method solved joint-working equations of the propulsion system by Newton iteration method to obtain cooperation points of the system. A full-power holding (FPH) requirement and turbocharger-engine collaboration condition were stated. The regulating rules in both FPH mode and power lapse (PL) mode were analyzed. The influences of regulating rules on turbocharger operating lines were placed. Finally, the altitude–velocity characteristics of the propulsion system and components were investigated. The research shows three results. This method converges rapidly that usually it needs only 5–6 iterations to obtain one operating point. The regulation scheme of two gas-bypass valves cannot only meet the design objectives but also allow an effective adjusting to the operating points of the turbochargers. This method can be extended conveniently to the simulations of more complex multistage turbocharging systems.