Study On Control Method For Air Fuel Ratio With Hydrogen Of Gasoline Engine Under Accelerated Transient Conditions

Currently, China is in the contradiction between rowing demand for cars and deterioration of environmental pollution and energy crisis. According to the analysis, when a car runs in transient conditions, the actual air-fuel ratio deviate from theoretical air-fuel ratio, resulting in the three-way catalyst decrease in conversion efficiency, which is the main causation of the automobile exhaust pollution. So, in order to reduce automobile exhaust pollution, the core problem is to improve the control accuracy of the transient air-fuel ratio. Only by solving the core problem can we improve the combustion efficiency of gasoline engine and the conversion efficiency of the three catalyst, so as to improve the fuel economy and emissions of the car.For this, through the analysis of the dynamic effect of the oil film formation mechanism and its impact on air-fuel ratio, and combined with hydrogen excellent combustion characteristics, this paper proposed a compensation method of doped hydrogen to control the air-fuel ratio in accelerated transient condition within the target theoretical value. And eventually to realize the target of reducing automobile exhaust pollution and alleviate the energy crisis to a certain extent. The main innovation and research contents of this paper:(1) Analyses the dynamic effect of the oil film formation mechanism and its influence on the transient air fuel ratio. For two key parameters X and? of film model, establishing an identification model based on chaotic time series LS-SVM, and compare this identification method with BP neural network and Elman neural network to do the simulation test and analysis. Thus, verify the effectiveness of the method.(2) Combining with the oil film model and hydrogen calculation module, convert the required compensation amount of gasoline under acceleration transient conditions into hydrogen amount. And establishing a gasoline engine intake system model and a oil system model based on mean value method, to form a complete model of gasoline mixed with hydrogen air-fuel ratio.(3) Design air-fuel ratio of gasoline mixed hydrogen control system. Based on MATLAB/Simulink simulation platform, do control simulation in different acceleration transient conditions. The results show that the hydrogen compensation is superior to no hydrogen compensation, chaos optimization least squares support vector machine control is superior to the inverse model control.