Study On Energy Consumption And Emission Characteristics Of Motor Vehicles Considering The Expressway Alignment

With the rapid development of economy and average income in our country,and the rapid growth of motor vehicles in urban areas,the prevention and control of urban road exhaust pollution and the reduction of energy consumption and emission of motor vehicles have become important issues in our country.Vehicle exhaust emissions are subject to the vehicle’s own driving conditions,road alignment and traffic environment and other factors.Analyzing the influence of the road alignment parameters such as longitudinal slope and the curve radius on the running speed and fuel consumption of vehicles is of great significance to reduce the urban traffic energy consumption and build a green traffic city.This thesis relies on the National Natural Science Foundation of "low carbon-oriented urban transport system optimization and management" to study the impact of urban expressway space alignment on vehicle energy consumption.Four typical horizontal curve sections in Hefei are selected as research objects,and the influence of horizontal curve radius on the fuel consumption and emissions of motor vehicles is studied.Firstly,the changing law of the vehicle speed when driving in the horizontal curved section and the relationship between the fuel consumption of a hundred kilometers of a motor vehicle and the curve radius is studied and analyzed,and the fuel consumption prediction method for a horizontal curve section is proposed.Through video velocimetry method,the section speed and traffic status data of horizontal curve sections in Hefei were collected.Meanwhile,the fuel consumption per second and vehicle speed were collected by the test vehicle method.Based on the experimental data,the relationship between the average cross-section velocity and the radius of the horizontal curve was analyzed,and the vehicle speed prediction model and the vehicle speed standard deviation prediction model were established with the alignment parameters and traffic parameters as variables.Using random number theory to establish the spatial variation of the speed of the section along the road direction.Based on the Carsim platform,the vehicle dynamic simulation model of the prototype vehicle was established.The law of the speed change of the vehicle was taken as the input of the fuel consumption simulation.The result of simulation was compared with the fuel consumption of one hundred kilometers under the same road environment.The results show that the error between the two is within 5%,which verifies the accuracy of the speed change pattern.Secondly,this paper study the influence of horizontal curve radius on vehicle emissions.The model of COPERT Ⅳ was selected,and the pollutant emission factor of motor vehicle in Hefei was calculated by collecting the model localization parameter information.The influence of driving speed and horizontal curve radius on the emission factor was analyzed,and the relationship between the emission factors and the velocity of different pollutants was fitted.The forecast model of pollutant emissions of light-duty vehicles in the horizontal curve section of Hefei city was established and the calculation was carried out.The research results of this thesis can provide reference for road design and energy consumption evaluation of road traffic,which will help to reduce the urban energy consumption.