چكيده به لاتين
Investigating air piston engines is crucial to recovering power at altitudes using turbocharger technology. Correct selection of turbochargers and their adaptation to the engine can help the engine breathe at altitudes, preventing the engine from lowering and also increasing the engine's flight altitude by maintaining the power output.
In the present study, a 4-cylinder internal combustion engine was modeled using one-dimensional modeling and commercial software GT-Power. The engine was initially modeled with its original turbocharger (base turbocharger) selected by Garrett, and the results of the software were compared with the results provided by the air engine manufacturer. According to the manufacturer data, the engine, with its base turbocharger (GT25), can fly up to 16,000 feet. In this study, a one-stage turbocharger and a two-stage turbocharger were selected to increase engine flight altitude to 24,000 feet and 40,000 feet and also to prevent a decrease in engine power at altitudes (maintaining engine power at altitudes). Finally, the performance of these two types of turbochargers was compared. The method used to select the right turbocharger is based on the calculation of the pressure ratio and mass flow rate of the inlet air to the engine at any particular altitude, while at the same time being a simple and practical method.
The modeling results showed that by choosing the GT2052 single-stage turbocharger instead of the primary turbocharger (GT25), the flight altitude can be increased to about 24,000 feet. At this engine altitude and rated speed (5500 RPM) the power output was reduced by about 9 percent over sea level power. Under the same conditions of engine rotational speed, The results of modeling and selection of two-stage turbochargers show that Altitude is increased to 40,000 feet compared to the GT2052 single-stage turbocharger. Production power also dropped by only about 4 percent as sea level rose to 40,000 feet. The trend of changes in brake specific fuel consumption is the same for all states as altitude rises to 16,000 feet. But from 16,000 feet onwards, the brake specific fuel consumption in the two-stage turbocharger mode declines compared to the single-stage modes and reaches a maximum of 0.478 (lb/hp.hr) at 40,000 feet. It turns out to be equivalent to the GT2052 single-stage turbocharged fuel consumption at 24,000 feet.
