Research On Hardware-in-loop Technology For Feedback Control For Marine Low Speed Engines Based On In-cyinder Pressure

Due to its high power,low fuel consumption and high reliability,marine low speed diesel engines are widely used in the main power of large oil tankers,container ships and bulk carriers.However,when the technology of marine low speed diesel engine develops rapidly,people are increasingly demanding issues such as environmental protection and energy crisis.Therefore,the requirements for noise,emissions and efficiency of marine low speed diesel engines become more and more strict.At present,the control of marine diesel engines is based on the whole diesel engine.In the actual working process,there are still some differences between the cylinders and the cycles,so cylinder pressure closed-loop control is applied to the cylinders,which can reduce the differences and improve the diesel engine control accuracy.Therefore,cylinder pressure closed-loop control technology is an inevitable requirement for the development of diesel engine technology.But the application of this technology takes time to accumulate.The cylinder-in-the-loop feedback control hardware-in-the-loop technology studied in this paper aims to provide a test platform for more in-depth application research in the future,saving the actual machine test cost and reducing or avoiding the risk of real machine debugging.In this paper,the 6EX340 EF marine low speed diesel engine independently researched and developed by CSSC Power Research Co.,Ltd.is used to study the combustion imbalance between the cylinders and the cycles of the marine low speed diesel engine.According to the specific requirements of the marine low speed diesel engine cylinder pressure feedback control system,develop a rapid prototype of marine low speed diesel engine cylinder pressure feedback control combined with NI cRIO hardware and NI LabVIEW software.Real-time simulation model of this type of marine low speed diesel engine is built using AVL Cruise M software.Using AVL Cruise M software,the marine low speed diesel engine cylinder pressure feedback control strategy is written,and combined with real-time simulation model,the cylinder pressure feedback control software-in-the-loop is simulated to verify the feasibility of the control strategy.Test and verify the rapid prototype and control strategy of marine low speed diesel engine cylinder pressure feedback control on the hardware-in-the-loop simulation platform.The main research contents and results are as follows:(1)Analyze the requirements of 6EX340 EF marine low speed diesel engine cylinder pressure feedback control rapid prototyping,and complete the overall design of the rapid prototype.According to the specific requirements of cylinder pressure feedback control rapid prototyping,develop position management module and cylinder pressure acquisition analysis processing module combined with NI cRIO hardware and NI LabVIEW software.The combustion characteristic parameters IMEP and CA50 extracted from the cylinder pressure data are used as feedback variables,and select the corresponding control variable injection timing and injection pulse width,and the cylinder pressure feedback control strategy is designed to complete the rapid prototyping of cylinder pressure feedback control.Test results show that the basic functions of the control prototype can be used in the hardware inthe-loop test for cylinder pressure feedback control.(2)Real-time simulation model of 6EX340 EF marine low speed diesel engine is built using AVL Cruise M software.According to the specific requirements of cylinder pressure feedback control,improve simulation model fuel injection module,and add fluctuations between the cylinders and the cycles.Then,verify this simulation model,and the results show that the error between the simulated value and the test value of the cylinder pressure signal is within 5%,and the real-time factor is always less than 1,meeting the requirements of accuracy and real-time.The real-time simulation model and the developed cylinder pressure feedback control strategy are combined to build a software-in-the-loop simulation platform,and a software-in-theloop simulation scheme is developed according to the actual situation,and the software-in-the-loop simulation test is carried out.The test results show that the cylinder pressure feedback control strategy improves the fluctuation between the cylinders and the cycles.(3)The 6EX340 EF marine low speed diesel engine real-time simulation model,hardware-in-the-loop simulation system and controller are integrated to form a closed control loop.The feasibility and control effect of cylinder pressure feedback control are verified by hardware-in-the-loop simulation test.The test results show that the cylinder pressure feedback control strategy can reduce the fluctuation of about 1 time,and has an improvement effect on the combustion imbalance between the cylinders and the cycles.This paper mainly researches and develops the rapid prototype and control strategy of the cylinder pressure feedback control for marine low speed diesel engine.Combined with the established real-time simulation model,the software-in-the-loop simulation platform and the hardware-in-the-loop simulation platform are established.Through experimental tests,the developed cylinder pressure feedback control rapid prototyping and control strategy can improve the fluctuation between the cylinders and the cycles,laying a foundation for further research and application.