Research On Control Strategy Of Dual Fuel High Pressure Common Rail Diesel Engine

Ignited natural gas dual fuel diesel engine power can reach the level of the original machine, and has good economic performance and emissions performance, it is an important way to improve diesel fuel economy and emission properties. In the study dual fuel engine performance, electronic control technology is the future orientation, where good gas injection control strategies, policies and various air-fuel ratio control condition control strategy to optimize engine control work processes, improve engine power, economy and emissions.A YN38CRD2 diesel engine as the research object, the original machine converted into CNG/diesel dual fuel engine. By analyzing the demand for dual-fuel engine control system for CNG supply system optimized design, using sequential injection intake manifold ways. A good nozzle mounting position, complete the installation and commissioning of various sensors, introduce dual fuel engine works and proposed dual fuel system control program, namely:according to the target replacement rate and calorific value of the principle of substitution, calculated fuel ignition and the quality of natural gas, according to the characteristics of natural gas nozzle, the quality of the natural gas will be converted into the corresponding injection pulse width PWM.Design of the dual-fuel engine input signal processing strategy, sub-cylinder drive. Basic control process:the engine speed calculation, the amount of fuel to achieve each air-fuel ratio control, jet injection timing and pulse width PWM control. Based on different operating conditions of the engine, the CNG/diesel dual fuel engine operating mode is divided into stop mode, start-idle mode, normal mode, transition mode and speed limiting mode to determine the mode conversion between the conditions, and thereby design conditions Analyzing strategies; conditions processing strategy includes starting condition, idle condition, conventional conditions, transition conditions and limiting conditions treatment strategies. Test dual fuel engine injection, the measured data MAP calibration results show that natural gas injection control system to accurately control the timing and jet pulse jet ejection drive waveform meet the design requirements. Be pure diesel and dual-fuel engine load characteristics in modes and external characteristics test, comparative analysis of power, economy and emissions performance dual fuel engine. The results show that the dual fuel engine power close to the original machine, the speed fluctuation can be stabilized within 20r/min, to achieve the smooth operation of dual fuel engines, and achieve savings in fuel costs and reduce emissions.