Development of Quick Response Fuel Injector for Direct-Injection Gasoline Engine(Fluids Engineering)

Abstract

Reducing exhaust emissions and improving fuel economy of gasoline engines have been very important for global environment. For exhaust emissions reduction, we developed boundless injector by separating moving part into two parts to minimize coarse droplets due to valve bounce at closing. For better fuel economy, reduction in minimum injection quantity decreases fuel consumption. Pulse width controls injection quantity, so quick response fuel injector enables reducing minimum injection quantity. Valve closing delay time is dominant for injection period compared to valve opening time, so minimum injection quantity depends on the closing delay time. Injector needs to reduce the closing delay time for decreasing the minimum injection quantity. We listed two factors (electromagnetism and kinematics delay). For quick response of the magnetic circuit, injector needs big magnetic force at low current. The diameter of magnetic suction area is extended and is shorten the magnetic circuit. For quick response of moving parts, injector needs to decrease the hydraulic resistance of moving parts. So we improved the anchor shape. Consequently we developed the quick response fuel injector.