Research On Gasoline-Hydrogen Dual Injection Engine Control

Hydrogen has excellent physical and chemical properties,its air-fuel ratio is much higher than that of gasoline,and it can be burned under a leaner mixture,which can keep the engine in a good combustion state without fire.Based on the GDI engine,this thesis constructs a gasoline-hydrogen cylinder internal injection control system,develops the in-cylinder pressure real-time acquisition system software,and uses the electronic control system calibration platform to perform on-line calibration of the original ECU and hydrogen injection auxiliary control ECU parameters.Test to achieve gasoline-hydrogen dual injection engine control research.The main research contents of this thesis are as follows:(1)A hydrogen direct injection system was constructed.The direct injection system mainly includes a hydrogen generator,a digital mass flow meter,a common rail,an injector,a spark plug with a hole,and a hydrogen injection control unit,and the hydrogen is directly injected into the cylinder through a spark plug with a hole,based on the original gasoline engine.The crankshaft and camshaft sensor signals control the hydrogen injection to form a dual injection engine that is directly injected into the gasoline-hydrogen cylinder.In order to accurately measure the hydrogen injection amount,the relationship between the hydrogen injection flow rate and the injection pulse width at different pressures and different rotation speeds is determined by experiments,and the corresponding initial map is established.(2)Developed a real-time in-cylinder pressure acquisition system based on pressure sensor,charge amplifier,high-speed synchronous data acquisition card and computer hardware system.The data acquisition system software was developed by LabVIEW language to realize real-time synchronous acquisition and data of cylinder pressure.Features such as storage and curve drawing.The calculation model and calculation program of the average indicated effective pressure IMEP are established by Matlab/Simulink respectively,and the offline and online calculation of IMEP can be performed according to the measured cylinder pressure.(3)Experiment design for calibration of control parameters.The experiment scheme is designed for two typical working conditions of idle speed and partial load condition.The former maintains the target with idle speed and excess air coefficient to determine the optimal hydrogen injection timing under different hydrogen injection pressures.Under the condition of constant load and speed,the excess air coefficient is used as the controlled parameter,and the hydrogen pulse width is used as the control variable to determine the optimal hydrogen-doping ratio for stable combustion under lean state.(4)Calibration of control parameters of the composite injection system.With fuel as the target,based on emission,based on the principle of energy balance,under different engine operating conditions,according to the target air-fuel ratio,the hydrogen-injection ratio is adjusted by controlling the fuel injection amount and the hydrogen injection amount,and the injection timing is changed.Controlled combustion is achieved by hydrogen injection timing and ignition advance angle.According to the comprehensive analysis of test data such as cylinder pressure,torque,total discharge temperature,fuel consumption and emissions,the optimal control parameters are sought.Through data analysis,100° is the optimal hydrogen injection timing of the composite injection system under idle conditions;under the partial load condition,the optimal hydrogendoping ratio of the excess air coefficient at 1.0-1.5 is 1.99%,2.18%,3.51%,3.51%,3.56%,and 5.10%.