![]() It was found that the DI combustion system yields several advantages: better take-off performance (higher power output), lower fuel consumption at cruise conditions, improved altitude performance, and reduced cooling requirements. Therefore, the analysis of scavenging and combustion processes of heavy fuel direct injection small APEs is the key to improving the comprehensive performance of the engine. Excessive fuel accumulation on the surface of the combustion chamber due to the contradiction between the fuel spray penetration distance and the combustion chamber diameter, increased smoke emissions at high loads. Due to the small displacement and high-speed reciprocating motion of the cylinder, the fuel-air mixing, combustion space, and time are greatly limited during direct injection in the cylinder, and combustion organization is difficult. For an aircraft diesel engine, the priorities for optimization are reliability and performance. It can be predicted that HF-APEs will gradually replace the existing aviation gasoline engines and become the main power system of general aviation aircraft, as well as long-endurance UAVs in the future. ![]() The design parameters of the combustion chamber and the operating conditions of APEs have a direct impact on combustion and emission characteristics. ![]() Therefore, small internal combustion (IC) engines are still the main powerplants of model airplanes. In addition, the current controller cannot fulfill all the tasks faultlessly in the energy management process. However, the series-parallel hybrid system is not suitable for small UAVs because it requires transmission systems. In recent years hybrid power systems are gradually developed in general aviation due to their excellent power performance and economic performance. ![]() Compared with four-stroke engines, the high-speed two-stroke engine for light aircraft has higher specific power per weight and displacement volume, as well as better thermal efficiency. The results have important significance for the development of the combustion system of small 2-Stroke Direct Injected HF-APEs.Īs is well known, aviation piston engines (APEs) are developing toward high power density. Finally, when the injection advance angle moves forward by 4 ☌A, the maximum pressure increases by 2 MPa, with the rising rate decreasing gradually. When the injection timing is between −8 ☌A and −16 ☌A, the engine has the optimal power and economy performance at different altitudes. Moreover, approximately 25% of exhaust residual gas in the cylinder is conducive to the fuel atomization and evaporation process in a high-altitude environment. ![]() In the compression process, the swirl ratio (SR) gradually increases, and the peak SR reaches 15. By comparing the simulation results to the experimental results, it showed that multi-ports cross scavenging can generate unbalanced aerodynamic torque in the cylinder. A 3-Dimentional transient model of in-cylinder flow and combustion process is established by the Forte platform, and the engine test system is set up. This paper describes a numerical and experimental study of scavenging and combustion processes on a 2-Stroke Direct Injected HF-APEs for light aircraft, with its cylinder specifically designed as cross scavenging. Heavy-fuel aviation piston engines (HF-APEs) are widely used in general aviation and unmanned aerial vehicle (UAV) due to their safety and fuel economy. ![]()
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