Research On Fuel Synergy Control Technology For Marine Diesel/Methanol Dual-fuel Engine

This paper aims to address the challenges faced by the internal combustion engine industry for ships under the goals of carbon peak and carbon neutrality,and to explore the application of methanol as an alternative marine fuel in marine diesel engines.Due to the characteristics of methanol,such as its lower cetane number,rapid combustion rate,and larger vaporization latent heat,its combustion process can effectively reduce the emissions of soot and NOx.Although there is already a foundation of research on methanol blending in diesel engines in China,most of it focuses on automotive engines,while research on marine engines is still in its infancy.Therefore,this paper will focus on the study of methanol blending control technology in marine diesel engines.In this study,guided by the needs of control strategy and algorithm verification,a one-dimensional simulation model based on GT-POWER is constructed and calibrated using experimental data.After calibration under three typical operating conditions in propulsive characteristics,the experimental data and simulation results are basically consistent,with the maximum error within 5%.This indicates that the one-dimensional simulation model is suitable for subsequent control strategy verification.A complete control strategy model for a diesel/methanol dual-fuel engine based on modular modelling software is established,mainly including state management strategy,fuel injection control strategy,and signal processing module.Subsequently,considering the characteristics of methanol fuel combustion and the impact of methanol blending on diesel engine combustion and performance,a targeted fuel management control strategy is constructed for the dual-fuel mode.To address the engine speed control problem for marine engines,a model predictive control(MPC)algorithm is employed for speed control of the dual-fuel engine with nonlinear characteristics,and a multi-model predictive control method based on fuel injection quantity weighting is proposed to achieve smooth operating condition transitions.A real-time simulation environment for rapid prototyping verification is built using the NI-Pharlap system,integrating controller models and GT-POWER models.Through real-time simulation analysis,the engine speed control performance of the model predictive control(MPC)speed controller and the traditional PID controller in dual-fuel mode are compared.Under stable load conditions,the MPC speed tracking control performance is better than the PID controller.In speed control experiments with sudden load changes,the MPC speed controller has demonstrated superior robustness and shorter stabilization time.Furthermore,to solve the steady-state error problem of speed control during sudden load increases,a multi-model predictive control(MMPC)controller based on fuel injection quantity weighting is employed and achieves good results.