CNG Cylinder Research Engine Low Pressure Injection Control

Direct injection into the high-pressure direct injection of natural gas and low pressuredirect injection, low-pressure gas inlet jet injection adequately address the existence of theblow at the same time can help solve the problem single-point injection tempering presence,able to high-pressure gas cylinder injection basis.Use established physical AMESim simulation model CYFZ1electrically controlled gasnozzle type, nozzle through CYFZ1simulation analysis results CYFZ1type gas nozzle gasinjection line with the conclusions of law, as a simulationg test nozzles.The establishment of a four-cylinder gas engine improvements mean combustion model,using PID and fuzzy PID simulation for the relevant idling, idling derived fuzzy adaptive PIDcontrol for better conclusions. To verify the improved dynamic stability of the model, theload on the idle condition from18N to21.5N, throttle from7°to10°for the relevantsimulation results show that the idle speed when the external load is still stable mutations in800r/min, in the air-fuel ratio when the throttle mutations still stable after a slight concussionin the vicinity of the theoretical air-fuel ratio, the model can be drawn a conclusion in theidling good dynamic stability. In order to alleviate the late jet MAP calibration graphmatching workload, a set of calibration gas engine simulation systems, preparation of800-4000rev/min the initial steady-state operating conditions of jet MAP chart, using BPneural network is optimized, data optimized for late MAP calibration graph matching theappropriate adoption.In order to reduce the heat generation of the MOS transistor and a solenoid valve, toimprove the stability and service life of the injection system. In terms of hardware: thedesign of the input signal processing module, the central control unit MCU, the low pressurecylinder charge pump injection nozzle of PWM solenoid driver circuit, the driver circuitthrough the nozzle to achieve a "high open, low hold" driven approach, combined withappropriate laboratory equipment for the nozzle solenoid valve system functional simulationexperiments. The results showed that: injection control system can complete a certain extentaccurate pulse jet control, solenoid valve drive current waveform meets a complete cycle ofthe pulse width of the jet injector waveform requirements can be drawn from the drive circuitcan realize reduced it. To study the driving voltage, PWM wave cycle, PWM duty cycle ofthree waves affect driving performance of the solenoid valve, the control carried out atdifferent voltages、different wave PWM cycle, the duty cycle of the experiment under the comprehensive experimental study of three affected by the nozzle current, relevantconclusions drawn, and finally tested nozzle flow verification system to further draw thedesign features of the drive circuit can be realized.Hardware: input signal processing module is designed, the central control unit, thecharge pump type in-cylinder injection pulse width modulated low voltage nozzle solenoidvalve drive circuit, the circuit implementation of the "open pressure, low hold" drive.Conducted a nozzle solenoid valve system functional simulation experiments were testedsimultaneously jet flow verification.To better control the software aspects of CNG engine injection control strategy studiescompleted Its software and flowchart design, including input signal program, jet controlprocedures, system main jet width calculation.