Current Situation and Trend of the Traction CVT

In a toroidal CVT, power transmission is accomplished by means of a special traction oil that displays high shear resistance under a state of high pressure . A toroidal CVT can be used even with engines that generate large torque and provide excellent ratio change response and high efficiency . The history of research of the toroidal CVT are summarized and the toroidal CVT up to date is reported. The varieius aspects on the toroidal CVT are summarized ,including EHL theory , toroidal double cavity system,traction fluid ,ratio control system, traction drive system , efficiency analysis ,and so on. Finally ,The development of the toroidal CVT in the future is indicated.     

Integrated Control Strategy for Dual State Continuously Variable Transmission System

Continuously variable transmission (CVT) is the ideal transmission for automobile, it is also one of the most important research items of researchers and automobile companies all over the world. In order to research vehicle with torque converter as starter and metal pushing belt as high speed transmission equipment(dual state CVT system), based on the test data of engine and torque converter, the integrated control strategy for vehicle with dual state CVT system is proposed and integrated control simulation for car with dual state CVT system is finished at the condition of multi mode. The research results provide the theory method of analysing and designing for CVT vehicle.     

Control strategy of regenerative braking for hybrid electric vehicle based on engine braking

Focusing on a continuously variable transmission(CVT) hybrid electric vehicle with integrate starter generator(ISG), modeling and simulating of engine braking was conducted. An optical control strategy of regenerative braking was put forward. When there is no regenerative braking, engine brake force can be used effectively by changing the CVT ratio to reduce the braking force requirements for wheel brakes based on the calculated results of engine braking. When there is regenerative braking, the braking priority sequence is generator braking, engine braking, and finally frictional braking. A forward simulation model for regenerative braking system of hybrid electric vehicle was built. The simulation and analysis under typical driving cycles was conducted. The result shows the control strategy and the models are reasonable and feasible.     

Modeling by Bond Graph and Simulation for a Metal Pushing Belt Continuously Variable Transmission System

Continuously variable transmission is the ideal transmission mode, the Metal Pushing Continuously Variable Transmission (CVT) is the most mature CVT used in vehicle at present. By studying the transmission mechanism and ratio change characteristics of Metal Pushing Continuously Variable Transmission system, and using the bond graph theory, a bond graph model of continuously variable transmission is established in this paper, and the state space function is derived. Based on the model, The simulation of transmission characteristics of a CVT car is studied, the simulation result shows that the dynamic characteristics of continuously variable transmission could be expressed in this model. The research results can provide the theoretical analysis method and design basis for CVT vehicle.[WT5HZ]     

Design Method of a Metal V-belt CVT Hydraulic System

The design method on the hydraulic control system is one of the key technologies of a metal V-belt continuously variable transmission(CVT).It can change the ratio of the transmission system by adjusting the pushing force of the pulley.By analyzing the structure characteristics and force relations,the design method of an important parameter of the CVT hydraulic system and the rate of transmission ratio,are put forward by simulating to the emblematical driving models.The structure parameters of the hydraulic system is gotten and validated by simulation on specific driving model.An effective design method is provided to develop the continuously variable transmission system.     

Synthetic Control Strategy for a Car With Hydro-mechanical Continuously Variable Transmission System at Standing Start

Continuously variable transmission (CVT) is the ideal transmission for automobile, it is also one of the most important research items of researchers and automobile companies all over the world. The dynamic simulation model is established and integrated control strategy of standing start is proposed for dual mode CVT vehicle, aiming at automatic vehicle with torque converter as a starter and metal pushing belt as a higher transmission equipment (Dual mode CVT vehicle), on the base of engine and torque converter performance experiment. Simulation result shows that vehicle performance can be improved by using the control strategy proposed. The research results provide the theory method of analyzing and designing for CVT vehicle.     

Powertrain parameter design for the electric vehicle with taking the energy consumption of air conditioner into consideration

On the basis of considering the influence of air conditioner on vehicle performance,the parameter determination of the power train composed of a battery,a traction motor and a two-speed transmission of an electric car is carried out. To ensure the economy of operation,a shifting strategy with a principle which emphasizes the high work efficiency of the power train is drawn up and the gear ratios are corrected aiming at the least energy cost over the drive cycle. The simulation results indicate that the designed parameters meet the requirements moderately and the driving range is extended by 5.28% when the air conditioner is turned off and 4.29% when turned on,compared with the initial results through the correction of the gear ratios.     

Study and Simulation on Control Strategy for CVT Ratio in HEV when Regenerative Braking

In order to satisfy the safety of vehicle braking and the fuel economy,a control strategy for regenerative braking force distribution is proposed by considering of battery SOC and braking severity.In addition,a CVT speed ratio control strategy is proposed to operate the motor in the high efficiency area to improve motor generating efficiency.A simulation model of mild hybrid electric vehicle is set up.Simulation result on ECE+EUDC typical driving cycles show that the effectively regenerating energy of braking of hybrid vehicle with CVT is lager than that of hybrid vehicle with MT by 2.5%.     

搭载机电控制无级变速器混合动力汽车模式切换仿真分析

通过分析机电控制无级变速器(electrical-mechanical continuously variable transmission,EM-CVT)的结构特点,提出了搭载EM-CVT混合动力汽车的传动方案,建立了动力源数值模型、EM-CVT模型,分析了混合动力系统工作模式,并针对模式切换时的冲击问题,以减小冲击度为目标,通过分析典型工况下动力源输出转矩特性和各部件的动态特性,提出了基于发动机、ISG电机、自动离合器以及EM-CVT相互协调控制策略。利用MATLAB/SIMULINK仿真平台建立混合动力传动系统动力学模型,并对典型的模式切换过程进行了仿真分析。结果表明,所提出的控制策略能够有效控制混合动力传动系统在模式切换时产生的冲击,提高了混合动力汽车的驾驶舒适性。     

Optimize Design on Pitch Radius of Metal V-belt Type Continuously Variable Transmission

Continuously variable transmission (CVT) is the ideal transmission for automobile, it is also one of the most important research items of researchers and automobile companies all over the world. By studying the force relationship of metal V-belt type continuously variable transmission, an optimum pitch radius is derived to maximize torque capacity, also a design procedure for optimum pitch radius is listed. The design procedure is applied for the true application, the calculation result shows that the torque capacity of belt transmission can be improved by optimization of the pitch radius. The research results provide the theory analysis method and design base for CVT vehicle.     

Application of Hydraulic Torque Converter Incorporated in Mechanical Continuously Variable Transmission

Continuously Variable Transmission which is the ideal transmission for automobile can improve dynamical and economical performance and reduce pollution emission effectively. Vehicle equipped with CVT where hydraulic torque converter is acted as start clutch have better acceleration performance and its starting control is very simple. Based on performance test of hydraulic torque converter and simulation on lock-up dynamic process of torque converter clutch, matching characteristic between engine and torque converter is evaluated , and the lock-up control rule of torque converter clutch and the control strategy of standing start of vehicle equipped with Continuously Variable Transmission with torque converter is proposed. By computer simulation on start process, vehicle equipped with CVT have better acceleration performance than equipped with five-speed MT.     

Analysis of Equilibrium Runing Lines of Engine and Hydraulic Torque Converter for a Vehiele with CVT

The mathematical model of the torque converters is established based on test results. Equilibrium running lines of engine and hydraulic torque converter are analyzed. The idea of matching and controlling is put forward for CVT vehicle with torque converter in starting ability, crawl ability and fuel economical efficiency, which lays a foundation for the exploitation of CVT vehicle with torque converter.     

Coordinated torque control strategy for driving-mode-switch of strong hybrid electric vehicle

For a new type of strongly hybridized system, the vehicle ride performance is used as the study goal, a coordinated control strategy is put forward to suppress the torque surge after the analysis of the parameters changes of engine, motor, clutch and transmission during the driving-mode-switch process. The strongly hybridized vehicle simulation model is developed based on the coordinated control strategy. The typical drive mode switching process performance simulation and analysis are performed. The results show that introducing the coordinated control strategy reduces the torque surge during the driving-mode-switch process and improves the vehicle drivability.     

Analysis of Kinematic and Kinetic Characteristics of a Metal Pushing V Belt CVT

Based on the kinematic and kinetic characteristics, the friction model of a metal pushing V(belt continuously variable transmission (CVT) is established in this paper. The relation between applied forces and speed ratio as well as transmitted torque is analysed. The coputational formulas on the tension forces of steel ring and compression forces between metal blocks are derived. The theoretical bases for designing a metal pushing V belt CVT equipment and its control system are provided.     

Analysis on Oylindrical Worm in Traction Machine and Modifications

Cone enveloping cylindrical worm in traction machine as instance, theoretical analysis on cylindrical worm transmission has been theoretically analyzed, and efficiency test and load capability test of traction machine with YJ240 cylindrical worm have been done on open power gear experimental instrument. According to the experimental data, it indicates cylindrical worm have some weaknesses on load capability, efficiency, adjustment possibility of tooth backlash and so on. Therefore, on purpose of improving integral performance of traction machine, face worm with variable tooth thickness may be used as primary drive mechanism in traction machine instead of cylindrical worm.     

ENERGY TRANSMISSION MATHEMATICAL MODELS OF MAIN DRIVING SYSTEM OF MACHINE TOOLS

Based on the energy flow path of the drive links of machine tools and the consideration that there exists simultaneously various energy losses in machine tools in operation, the energy transmission mathematical models of the main driving system of machine tools are created by analysing synthetically the energy losses in the motor and mechanical system of machine tools, which lays a foundation for the studies on the energy transmission laws, energy saving and energy information monitoring in machining processes.     

Dynamic simulation of and experimentation with tracked vehicle hydrostatic steering characteristics of zero differential systems of a power shift steering transmission

This research investigated problems influencing tracked vehicles steering dynamic characteristics, such as rolling resistance during straight driving, steering centrifugal resistance, acceleration resistance during straight driving, scratching soil resistance of steering. Based on research about the relationship between the hydraulic steering regulation speed system and its maximum stable work pressure when vehicles have central steering on good roads (such as cement and rural roads), a zero differential hydraulic steering system of power shift steering transmission can ensure that vehicles maintain straight ahead stability through reasonably matching a steering drive system. The test indicates that vehicles have good dynamic characteristics when the work pressure accounted for 60% to 80% of the security work pressure.     

Hybrid Electric Vehicle and Its Electrical Drive System

Hybrid electric vehicle (HEV) is a mixture of electric vehicle and conventional vehicle, which has the merits of reducing exhaust gas and the consumption of gasoline HEV is the new development way of automobile industry. This paper introduces HEV, and discusses the essential framework of HEV drive system,the basic types of the electrical drive and their features and the present state of the development at home and abroad.Some key technologies are also proposed which determine the drive and control performance of HEV.     

Simulation for the Power System of Fuel Cell/battery Electric Vehicle

The developmemt and research of taking fuel cell /battery as electric vehicle power is a new direction in abroad. A real-time simulation model for power driving system of a fuel cellbattery powered electric virtual vehicle is established. This electric vehicle powered primarily by 30 kw proton exchange membrane (PEM)fuel cells, with Lead-acid battery as assistant power, and with focus classis as virtual vehicle classis.The electric vehicle is simulated on the advisor platform, and the NEDC driving pattern simulation results show that the electric vehicle can satisfy the need of performance.     

Drive-response Synchronization for Chaotic Systems

In the drive response method of Pecora and Carroll (the PC method), the response system is copied directly from drive system and is steady subsystem of drive system. But sometimes the PC method is disabled. Therefore, another method of realizing the drive response of chaos systems is put forward in this paper. The response system is not copied directly from steady subsystem of drive system, but is constructed from arbitrarily state variable of drive system. At the same time, the driving function is added in the response system, and the method of construction is pointed out. The method can realize the chaos synchronization that can not be realized by PC method.