Assessment of Gasoline Direct Injector Coking Effects on Spray Dynamics and Fuel Atomization

This paper presents study of multi-hole gasoline direct injector coking effects on spray dynamics and fuel atomization. Clean injectors were coked in extended fouling cycle in a multi-cylinder thermal engine. Deposit accumulation were characterized by fuel flow rate measurements. Optical tests were carried out in a constant volume chamber. High-speed imaging was used to quantify fuel plumes’ penetration length, plume cone angle and plume angle alternation due to deposit formation. Droplet size and velocities were measured with a Particle Doppler Phase Analyzer (PDPA). The experimental data was used to attain a better understanding of tip cocking effects in Gasoline Direct Injection (GDI) engines.