Optimization study on fuel injection characteristics of gasoline direct injection (GDI) engine fuel system

• Published in: Fuel (Guildford) 2025-02, Vol.381, p.133468, Article 133468
• Main Authors: Wang, Yongqi, Tian, Jie, Xiong, Yong, Wang, Lu, Ji, Shaobo, Cheng, Yong
• Format: Article
• Language: English
• Subjects: Fuel injection pressure; Fuel injector injection pattern; Gasoline direct injection; Simulation
• ISSN: 0016-2361
• DOI: 10.1016/j.fuel.2024.133468

•Developed an optimized GDI fuel system in AMEsim to reduce injection at high rail pressures.•The study suggests balancing fuel injection and closing delay by increasing needle lift at 100 bar, focusing on NVD.•Increase coil turns and needle lift to boost injector performance and offset reduced injection at high pressures.•This paper uses displacement method to measure fuel injection patterns. In the evolving automotive industry, GDI (gasoline direct injection) systems offer substantial benefits in fuel efficiency and emission reduction. However, they face challenges like reduced fuel injection quantities with increasing rail pressure. Therfore, this study employs AMEsim to build and validate a GDI engine fuel system simulation model, examining the effects of injector needle valve diameter (NVD) (1.8 mm, 2.0 mm, 2.3 mm), needle lift (0.05 mm to 0.125 mm), and opening voltage (96 V and 48 V) on injection patterns at pressures of 100 bar and 150 bar. Findings reveal that at 150 bar, injection quantity decreases as NVD increases due to the electromagnetic coil’s insufficient force, which impedes valve opening. Increasing driving current slightly enhances this force, but only modestly improves dynamic response. At 100 bar, the influence of NVD on injection volume diminishes. Raising the needle lift increases the maximum injection rate but also the closing delay, suggesting a balance between needle lift and NVD can optimize injection volume and timing. Higher opening voltages reduce opening delays but have a limited effect on larger NVD and escalate driving system demands. Addressing the decreased injection quantity issue involves augmenting the electromagnetic coil’s power by increasing coil turns and needle lift, thereby enhancing injector dynamic response to meet higher fuel demands.