Design And Implementation Of Gas Injection System For Diesel-LNG Dual Fuel Engine

The oil-fueled engine has a history of more than100years. But with the shortage of global petroleum resources and environmental pollution problem getting more serious, how to develop petroleum alternative fuels and improve the economy and reduce emissions has become an inevitable trend in the development of the engine industry. With the advantages of the flexible, efficient, and energy saving, diesel-LNG dual fuel engine will become an important development direction of the engine industry in the future.At first, the research status of diesel-LNG dual fuel engine gas injection system at home and abroad is described in this dissertation. Combined with the burning characteristics of natural gas on the basis of the traditional engine, a kind of new diesel-LNG dual fuel engine electronic injection control system architecture has been proposed. Then, the diesel-LNG dual fuel engine gas injection system control strategies and processes are analyzed and researched, which includes the system control strategy and software design principles, the dual fuel mode control flow at running smooth, the dual fuel mode control flow at working abnormal, the control flow of pure diesel mode and security policy of dual fuel engine.Then the mastered HT5dual fuel engine electronic control simulation platform is used to collect the simulation engine condition signals (speed, camshaft position, intake pressure and temperature, coolant temperature, each cylinder exhaust temperature, etc.) and control the actuators (jet solenoid valve, solenoid valve, stepper motors, etc.). Meanwhile, the electronic control simulation platform can establish data communication with the host computer via CAN communication mode. The host computer’s monitor calibration software HT_LINK can monitor and calibrate parameter of the engine operating conditions real-timely. In order to verify the control strategy of dual fuel engine gas injection system.The dual fuel engine used in experiment is not changing the basic structure of the original diesel engine, and just adding a LNG fuel supply system. The gas supply system uses the mode of inlet multi-point sequential injection, therefore the amount and time of natural gas injection can be more precisely controlled in each cylinder of the engine. Besides, the sensors and actuators are selected according to the characteristics of dual-fuel engine supply system.Finally, to do a large number of field tests under different conditions based on the modified diesel-LNG dual fuel engine, the experiment results show that the dual fuel engine’s dynamic performance is not be changed, while economy and emissions have been improved significantly compared with pure diesel engine, and this has a good marketing value.