سيدسينا ذكريائي نژاد

With increasingly stringent regulations on permissible levels of carbon dioxide an‎d other pollutants, as well as competition from electric an‎d hybrid vehicles, internal combustion engines require continuous optimization an‎d advancement. The use of natural gas as a cleaner fuel an‎d the development of direct-injection gas engines have received considerable attention due to their potential to reduce emissions an‎d improve performance. Additionally, direct water injection technology can effectively enhance thermal efficiency an‎d combustion performance. In this context, the development of control functions an‎d calibration for natural gas direct injection (NGDI) engines, particularly in the presence of direct water injection, requires a fast yet accurate model to predict the thermodynamic behavior of the cylinder, enabling its use in ECU development an‎d hardware-in-the-loop applications. In this study, a two-zone quasi-dimensional thermodynamic model based on crank angle was developed, which includes models for intake an‎d exhaust flows, heat transfer, combustion processes based on a two-step chemical reaction model coupled with a water-to-fuel (W/F) ratio correlation, an‎d a sub-model for direct water injection an‎d evaporation. The model was solved using the first law of thermodynamics with the aim of high computational efficiency. Model validation was carried out in three stages: in the motoring an‎d flow analysis using GT-Power with cylinder pressure errors of 2–8%, in a dry NGDI engine with errors of 4–12%, an‎d in a GDI engine equipped with direct water injection with errors of 5–10%. Sensitivity analysis regarding equivalence ratio an‎d spark timing changes also showed trends consistent with reference sources, indicating the model’s reliability for calibration purposes. Ultimately, the developed framework enables fast an‎d stable prediction of cylinder behavior an‎d can serve as an efficient tool for developing ECU control strategies an‎d virtual calibration. Keywords: Quasi-dimensional simulation; Two-zone modeling; Natural gas engine; Water injection; Direct fuel injection; Hardware-in-the-loop

شبيه سازي شبه‌ابعادي , شبيه سازي دو ناحيه‌اي , موتور گازسوز , پاشش آب , پاشش مستقيم سوخت , سخت افزار در حلقه

Quasi-dimensional simulation , Two-zone modeling , Natural gas engine , water injection , direct fuel injection , Hardware-in-the-Loop

Seyed Sina Zakaryaei Nezhad

Dr. Ali Ghasemian