Gas-electric System And Control Strategy Of Hybrid Cars Powered Plug-in

Now oil resource is excessive consumption, and environmental pollution is seriousincreasingly. The two problems directly threaten the development of traditional vehicle.Domestic and foreign car manufacturers are developing new energy vehicles. By energy conservation and environmental protection, mature technology and low cost, PHEV is the main direction of new energy vehicles. The new plug-in gas-electric hybrid integrates the advantages of natural gas vehicles and PHEV. It can simultaneously satisfy the urban road condition and suburban road condition. It’s energy conservation and emission reduction effect is obvious.This paper uses the mathematical calculation and simulation analysis method to study the plug-in gas-electric hybrid’s power system, each component parameter design and the vehicle control strategy’s optimization. The main research results are as follows:(1) Several structural types of hybrid power system are classified and evaluated. Combined with the analysis of the new car’s running conditions, the new power system uses a single axis parallel connection structure.The layout of the power system components is presented. With the analysis of the operation mode of the new car, this paper initially set the basic control scheme of the vehicle.(2) According to the vehicle’s parameters and performance indicators, the new power system selects LNG engine, ISG motor, lithium ion power battery and five gear synchronous mechanical operation transmission. According to basic control scheme and features of parts, This paper finished the design of motor’s rated power/peak power, rated speed/maximum speed, rated torque/maximum torque. It also determined the engine’s power range and speed range, power battery’s parameters, as well as the transmission ratio of the system.(3) This paper built the mathematical model of key parts’characteristic. The ADVISOR was secondary developed, The simulation model of power system and vehicle were established. The data file was rewrited. The vehicle’s definition and models of embedded were completed. After setting simulation environment and calculation of vehicle performance simulation, draw the conclusion:New car completely meets the index of power performance, fuel economy and emissions requirements. Synthetic fuel economy than GB27999-2011increased by62.5%, compared with the prototype car is increased by18.2%. Under the City and high-speed conditions, the new car’s emissions of gaseous pollutants can fully meet the national IV standard. At the same time put forward shortages:New car’s NOx emission cannot achieve national V standard, executed in the future. The dynamic system overall efficiency is low. It needs to optimize the control strategy.(4) This paper built a three layers BP network structure. It’s input layer’s neurons is established for the vehicle requirements speed, torque and the battery’s SOC. Output layer’s neuron is established for engine output torque. Combining with instantaneous multi-objective optimization algorithm, modified the initially electric assist control strategy based on logic threshold. By offline simulation results as the sample datas, train the neural network. Established multi-object real-time control strategy based on neural network, through the vehicle performance simulation, we can concludes that multi-object real-time control strategy based on neural network has better performance. It not only has good real-time adaptive ability, but also has realized the multi-objective control of power performance, fuel economy, emissions and power system efficiency. At the same time, The gaseous emissions can achieved at national V standard, and power system efficiency is also greatly improved.