Nano-Orifice Based Fuel Injector Design for Enhanced Combustion Efficiency and Reduced NOx Emissions in Aero Engines

Abstract

Fuel injection systems constitute the core of diesel engine operation, where the injector serves as a critical component responsible for delivering fuel under extremely demanding conditions involving cyclic hydraulic, mechanical, and thermal stresses. The injector nozzle, in particular, governs combustion efficiency by atomizing fuel at very high pressures into the combustion chamber, ensuring proper air–fuel mixing. In this study, a novel modification to the conventional nozzle design is proposed by transitioning from micro-scale orifice geometries to nano-scale openings. This dimensional refinement is intended to enhance spray characteristics, improve atomization quality, and potentially reduce harmful emissions such as nitrogen oxides (NOx). The injector considered in this work is derived from a twin-cylinder agricultural tractor engine, and its geometric parameters including nozzle dimensions and orifice specifications—are carefully referenced for accurate modeling. During operation, the injector is subjected to fluctuating fluid pressures, variable mechanical loads due to the repetitive motion of the needle valve, and elevated thermal conditions, with surface temperatures often reaching 200–300°C or higher. These combined loading conditions significantly influence the structural durability and fatigue behavior of the injector. To evaluate these effects, a detailed three-dimensional model of the fuel injector is developed using CATIA V5. Subsequently, fatigue analysis is conducted to assess the structural integrity under complex cyclic loading. The results enable identification of potential failure regions and estimation of safety factors, thereby providing insights into the injector’s reliability and performance under prolonged operational conditions.