Simulation Research On Heterogeneous Platoon Non-Uniform Arrangement Strategy Of Three Models For Energy Saving

With the progress of automobile manufacturing industry and the development of transportation industry,the total number of motor vehicles in China is increasing,and people’s dependence on transportation in production and life is also increasing.However,while the transportation industry makes people ’s production and life more convenient and fast,it also brings environmental pollution and energy consumption that cannot be ignored.In order to reduce environmental pollution and excessive consumption of energy,China has unswervingly taken the route of sustainable energy development,and relevant laws and regulations have been continuously improved.In this context,the research on energy saving and emission reduction of vehicles has great practical significance.According to the previous research experience,due to the close distance between vehicles,the aerodynamic drag characteristics of vehicles in the platoon will be affected by other vehicles in the platoon,so that each vehicle in the platoon has different degrees of aerodynamic drag reduction,to achieve the effect of energy saving and emission reduction.At the same time,when the vehicle platoon is driving,due to the differences in braking performance and vehicle size of different types of vehicles,it is more reasonable for different types of vehicles to travel in different spacing formations.Therefore,this paper innovates the arrangement of vehicle formation driving.According to the difference of vehicles in the braking process,the non-uniform arrangement model of vehicle platoon is established.The flow field of vehicle platoon composed of different types of vehicles under non-uniform arrangement is analyzed and studied by numerical simulation.The research object of this paper is the intelligent vehicle platoon driving under ideal conditions such as vehicle networking,that is,there are good communication conditions between vehicles and the acceleration and braking of vehicles are completed by the vehicle itself.Firstly,according to the relevant data of highway transportation,two-axle trucks,three-axle trucks and six-axle trucks are selected as the research objects of numerical simulation.Secondly,considering the traffic efficiency,Reynolds number and energy consumption,the initial speed of the vehicle platoon before braking is set to 80 km / h;thirdly,according to the selected simulation vehicle model and the initial speed of the queue,combined with the relevant national standards,the non-uniform arrangement model and the fuel economy model are established respectively.On the basis of this theoretical model,the numerical simulation of three vehicles driving alone and three-vehicle heterogeneous platoon driving conditions based on three types of vehicles is carried out.According to the change of velocity vector and the static pressure distribution of vehicle head and tail,the fuel-saving effect of each vehicle is analyzed by calculating the aerodynamic drag reduction rate and fuel-saving rate of platoon vehicles.For the three-vehicle heterogeneous platoon,the overall fuel saving rate of the vehicle platoon is between 5.83 % and 14.55 %.The 3-2-6 platoon has the best fuel saving effect,and the 3-6-2 platoon has the worst fuel saving effect.Similarly,this paper makes a numerical simulation analysis of three models in the four-vehicle heterogeneous queue driving condition.In order to ensure the accuracy of the fuel-saving effect analysis,the four-vehicle vehicle queue is divided into three groups according to the different composition of the vehicle queue.In the heterogeneous vehicle platoon composed of three-axle trucks,six-axle trucks and two two-axle trucks,the overall fuel saving rate is between 11.12 % and 25.27 %,and the3-2-2-6 platoon has the best fuel saving effect.In the heterogeneous vehicle platoon composed of two-axle trucks,six-axle trucks and two three-axle trucks,the overall fuel saving rate is between 9.17 % and 19.91 %,and the 3-2-3-6 platoon has the best fuel saving effect.In the heterogeneous vehicle platoon composed of two-axle trucks,threeaxle trucks and two six-axle trucks,the overall fuel saving rate is between 4.45 % and16.31 %,and the 3-2-6-6 platoon has the best fuel saving effect.Finally,this paper analyzes the decision-making of vehicle joining queue for heterogeneous queues of three models.The results show that under ideal conditions,the fuel saving rate of two-axle trucks in the queue is between 4.17 % and 44.99 %;when the two-axle truck has the intention to enter the queue,it should be in the third or fourth position in the queue as much as possible.The fuel saving rate of the three-axle truck in the queue is between-1.35 % and 22.63;when a three-axle truck intends to join the fleet,it should avoid being in the rear of a six-axle truck as much as possible.The fuel saving rate of six-axle trucks in the queue is between 1.90 % and 11.28 %.The influence of the change of the vehicle queue and the change of the position in the queue on the fuel saving effect of the six-axle truck is relatively small.