| With the increasingly stringent requirements of emission regulations around the world,not only strict requirements have been made on the quantity of particulate matter emitted from diesel engines,but also strict restrictions have been made on the quantity of particulate matter.With the increasingly stringent requirements of emission regulations around the world,not only strict requirements have been made on the quantity of particulate matter emitted from diesel engines,but also strict restrictions have been made on the quantity of particulate matter.The DPF must be regenerated in time with a certain carbon load to ensure safe and reliable operation of the DPF.The DPF carbon load cannot be directly measured in the actual application process and can only be predicted by indirect means.In view of the above problems,this paper focuses on the research of DPF carbon load model.This paper mainly includes three main contents:the establishment of mathematical model of diesel soot generation,the establishment of soot oxidation model by NO2,and the establishment of soot oxidation model by O2.Firstly,a three-dimensional simulation model is constructed according to the actual operating parameters of diesel engine.The accuracy of the three-dimensional model is verified by experimental data.By comparison,it is found that the simulation results of the cylinder pressure curve and soot emission data of diesel engine are in good agreement with the actual results,which can be used for subsequent research.Through theoretical analysis,the author determines that the engine speed and torque are the main influencing factors of diesel soot generation.Therefore,this paper uses the speed and torque as the simulation variables to calculate the soot generation quality of diesel engine under different speed and torque conditions.The results show that the diesel engine soot specific emission increases first and then increases with the increase of diesel engine speed.It also decreases first and then increases with the increase of engine load.A mathematical model of soot emission is established in MATLAB based on the double-tuning and spline difference method.The mathematical model automatically calculates the soot generation quality of the diesel engine for a given speed and torque.The experimental results show that the soot specific emission model based on double-tuning and spline interpolation can reflect the actual situation well,with an average error of 6.5%.Based on the chemical reaction process and Arrhenius formula,the mathematical formulas for the oxidation of carbon load by NO2 in DPF and the oxidation of carbon load by O2 in DPF are established respectively.According to the data obtained from the bench experiments,the formulas were tested and verified.It was found that the average error of the mathematical model of carbon load in DPF by NO2 oxidation was 6.5%,and the average error of the mathematical model of carbon load in DPF by O2 oxidation was 7.2%.The results show that the two mathematical models have high accuracy and can well reflect the actual situation.Finally,the DPF carbon load overall model is verified by experimental data,and the average error of soot net cumulative amount under different working conditions is 9.0%,which indicates that the DPF carbon load model established in this paper can reflect the actual working conditions more accurately. |
