Analysis on the influence of friction coefficient on the starting control of automatic mechanical transmission

Based on the fact that friction coefficient changes with the friction surface temperature,the influence of friction coefficient on automatic mechanical transmission (AMT) is studied during repeated starting process. A model is established for the transmitted torque of clutch and the temperature rise on clutch plate surface during AMT starting. Based on the launching control rule of “fast-slow-fast”,the repeated starting for AMT and the friction work of the friction pair are simulated. The simulation results show that friction coefficient changes with the change of the friction work. After several starting,friction coefficient and the transmitted torque of clutch diminish a lot,and the slipping between drive plate and clutch plate always exist, therefore,the vehicle can’t start.     

Design of data acquisition and communication system for AMTcomprehensive performance test bench

AMT (Automatic Manual Transmission) comprehensive performance test is one of the main means to develop and evaluate AMT. An overall scheme of the data acquisition and communication system for AMT comprehensive performance test bench is proposed according to the requirement of the test bench, and a communication network of data acquisition and communication system is built. The hardware and software of data acquisition system are designed. The experiments show that the system meets the requirement of data acquisition and communication system for AMT comprehensive performance test bench and it lays a foundation for AMT comprehensive test research.     

design of a closed loop control virtual test for vehicle handling stability

In an effort to address the high risks and qualification demands of test drivers, a vehicle model and a driver model were built based on ADAMS/CAR, an advanced block of ADAMS. The steering efforts test procedure was designed according to the national standard GB/T 6223.5—1994. A virtual test was performed in ADAMS, and the results calculated. The results show that the driver model possesses a strong capacity to charge the vehicle model. The virtual test results satisfy the evaluation index, indicating the virtual test can be used to test and improve vehicle performance.     

Automatic control strategy and its test analysis for the heavy truck AMT

By analyzing the startup process of automated mechanical transmission(AMT), fuzzy control algorithm of clutch engagement speed and constant engine speed in part during startup are proposed based on comprehensive consideration of driver’s startup intention and startup performance indices. Through dividing shift process of AMT into seven stages, clutch control logic and goal speed control algorithm of engine during the shift process are put forward. Aiming at the emergency braking condition, a control strategy of jump downshift during braking and a determination method of target gear are also proposed. In order to verify the validity of control strategy, an AMT prototype vehicle is developed and the test of startup, shift and jump downshift are carried out.     

Ratio control strategy for solving system response lag of continuously variable transmission system

Generally, there’s a system response lag in the continuously variable transmission system, and this leads to a deviation of the engine work point from the optimal operation line of the minimum fuel consumption. To reduce the influence of system response lag, a new CVT ratio control strategy with the system response lag parameter during computing target ratio is proposed. Simulation results indicate that the proposed control strategy can overcome the effect of system response lag, so as to keep the engine work point on the optimal operation line effectively. A comparison of fuel consumption is made between the proposed control strategy and the traditional one by simulation, and results indicate that the proposed control strategy reduces the fuel consumption of the system by 2.85％.     

Modeling and control system simulation of automobile DCT

In order to reduce development time and cost of dual clutch automated mechanical transmission(DCT) control system,the dynamic model of automobile DCT control system is established by Matlab/SimDriveLine and the engine model is improved by neural network.Based on Matlab/Simulink,the simulation models of DCT control during starting phase,shift phase and shift rule are set up,and then the whole system of DCT is simulated.The simulation result indicates that the DCT system dynamic model and the designed controller are reasonable and feasible,and proofs that the model is suitable for developing DCT control system and improves the design efficiency of DCT system.     

Design and development of propulsion system for CNG-electric hybrid city-bus

The design of propulsion system for CNG-electric hybrid city-bus is introduced based on the selection of driving cycle and the establishment of control strategy. Making program of powertrain’s configuration is included as well as parameters’ selection and matching of components such as engine, motor, battery and transmission. The simulation results show that the design meets the requirements. The components of the propulsion system are integrated together, and then they are installed into the sample city-bus. The roadway test has been done under the target driving cycle. Compared with the peer CNG city-bus, there are 28% increasing in the largest climb degree and the acceleration time of 0~50 km is reduced more than 1.8 s, and the fuel saving rate achieves to 22% under the typical city-bus driving cycle of China.     

Coordinated pressure control of a regenerative braking system based on a hybrid electric vehicle with an integrated startor and generator

With a focus on a Changan hybrid electric vehicle (HEV) with an integrated startor and generator (ISG), strategies for braking force distribution and coordinated pressure control are put forward, and a dynamic braking control model is constructed for off     

The compensation method for the random time-delay of the feedbackchannel and the forward channel in the networked control system

An improved predictive control method is presented to compensate the random time delay in the networked control system. The feedback time delay is compensated by predictive controller based on softened increment input strategy. The forward time delay is unknown for controller, so an extra feedback loop is added to compensate the delay by estimating the error between the actual control signal effected on plant and the output of controller in historical moment. For the controlled system with unknown or slowly varying parameters, the networked feedback correction algorithm is discussed based on a modified recursive least-squares identi cation algorithm. The system stability is analyzed and the simulation results show that the time delay in the networked control system can be accurately compensated. The excellent network performance is ensured with this strategy.     

石漠化防治区综合治理效益指标体系的构建及评价研究 ——以贵州关岭-贞丰花江示范区为例

以关岭-贞丰花江示范区为例,基于主成分分析模型,从生态效益、经济发展水平和社会发展水平3个方面进行评价指标的筛选以及指标权重的确定。最终确定影响生态效益的4个主要评价指标,影响经济发展水平的4个主要评价指标,影响社会发展水平的3个主要评价指标,构建出综合治理效益指标体系。根据选定的评价指标,采用模糊综合评判对花江示范区综合治理效益进行评价,将评价结果分为很差、差、一般、较好和很好5个等级。结果表明:示范区由治理前评价的"差"上升到治理后评价的"一般"。可以说明,治理措施在短期生态效益和经济发展水平方面有着良好的发展趋势,总体而言,治理措施具有良好的协调性和整体性。