Development Of Electrical Control System For Marine Natural Gas Engine Based On ?C/OS-?

The use of internal combustion engines brings great convenience to people's life,but also leads to a serious shortage of oil and environmental pollution and other issues.Facing the severe resource situation as well as harsh emission laws and regulations,the development of alternative fuel engines has become one of the means to solve the current problems.Because of good combustion,high calorific value and rich reserves and other advantages,the natural gas is the preferred alternative fuel for internal combustion engines.The work process of natural gas engine is complex,system must assure a precise control in the effective operation to make it fully achieve high efficiency,low emission technology.In order to achieve the precise control,this paper first develops the hardware and software of the natural gas engine,such as electronic throttle,wide area oxygen sensor,high pressure ignition assembly and gas injection valve.According to the system requirements,the corresponding hardware circuit design is given,and the hardware of each actuator is tested to verify the design rationality and its control performance.Then,based on the "multi-closed loop + feedforward" control algorithm,a new control strategy for natural gas engine is proposed to achieve the steady and stable response of the whole engine.In the steady state conditions,this paper use speed,throttle position and ?closed-loop control.In the transient state conditions,to ensure the stability of ?,this paper adopt feedforward open-loop control.Finally,this paper based on ?C/OS-? operating system to complete the software control system.The test performance of the electronic control system was designed and tested on the 6K test bench.The test results show that the engine speed fluctuation rate is about 1%,the maximum volatility of the excess air coefficient is 1.75%,which are maintained in a small range,indicating that the control system have good stability in the idle speed conditions.Furthermore,the experimental results show that the control system has strong robustness when the maximum air coefficient is increased to 1.14 and stabilized at about 1s in the steady state condition of the engine.Finally,this paper did a test in the transient conditions,the engine instantaneous rate of1.9%,excessive air coefficient transient rate of 8.4%,recovery time are about 4.5s,results are in line with the expected target requirements.The test results show that the control system developed in this paper can achieve the precise control of natural gas engine.