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.     

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.     

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.     

Contact Characteristics of Parallel Axle Toroidal Continuously Variable Transmission

An analytical study on the contact characteristics of the parallel axle toroidal CVT has been detailed. The shapes of the contact areas between the power roller and input as well as output disks are considered to be ellipses. Mathematical equations for estimating the torque capacity, power loss due to spin action, and contact efficiency of the elliptical contacts of the parallel axle toroidal CVT are formulated and expressed in the form of integrals which can be readily evaluated by numerical scheme. The contact efficiency calculations of the parallel axle toroidal CVT have been developed for a precise understanding of the spin effects under the effect of system parameters. Numerical results are presented, which can help the designer to select the proper system parameters to minimize the undesirable spin effects.     

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.     

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.     

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.     

Development and application of continuouslyvariable transmission test facilities

Basic structure and speed control principles of rubber V belt continuously variable transmissions (CVT) are analyzed. A test bench on which the governing characteristics, carrying capacity, pulley diameters, and transmission efficiency of CVTs can be tested is developed. This test rig permits the measurement of speed, torque and axial displacements of moveable flanges. The experiment not only verifies the results of the theoretical analysis but also reveals the trend of governing characteristics and efficiency affected by the operating condition changes. These conditions include the speed ratio, rotational speed, and external load. Based on this investigation, a method for improving CVT efficiency is proposed. The feasibility of the test bench is demonstrated by the experiment, which has a guiding role for design and parameter matching of CVTs.     

Testing Study on Hydraulic Torque Converter for Car

A test bed with computer control for hydraulic torque converter test is built up. The structure and principle of the test bed are introduced. The performance characteristic of torque converter for a CVT car is studied, and the mathematic model of the torque converter is established based on test results, which lays a foundation for the exploitation of automatic transmission car with hydraulic torque converter.     

Speed Ratio Matching Strategies of Metal V-belt Type CVT System

The ratio control strategy and the relevant pulley clamping control strategy of the Metal Pushing V-belt Type CVT C Continuously Variable Transmission are key technology of CVT system matching. The engine output torque model and oil consumption model are given in numerical table by cubic spline interpolation to fit engine test result. Based on the engine speed feature, the speed ratio changing strategy of CVT in the numerical table are given to realize the optimal fuel economy and optimal performance mode within the ratio range of the CVT system.     

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 of Misalignment of Metal Pushing V Belt of Continuously Variable Transmission

With numerical calculation method,misalignment magnitude of CVT Metal V Belt has been calculated when CVT is shifting.Accuracy of different calculation methods have been compared.Moreover,some way to resolve V Belt misalignment are also presented.     

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%.     

Ratio Control Principle and Mathematical Modal of Vehicle Traction Drive Type Continuously Variable Transmission

The traction drive continuously variable transmission is another kind of advanced transmission device for vehicle beside the metal pushing V_belt type CVT. It provides excellent driving performances including powerful driving capacity, high efficiency, good smoothness and economy, etc. The basic structure, transmission principle and the hydraulic servo control system of traction drive CVT are described. The mathematical model of the system is established. The study of this project provides the academic bases of further studying on the dynamic characteristics of CVT and vehicle.     

CVT刚性联接发动机曲轴轴系结构的扭振分析

因非道路车辆的特殊结构和成本限制,提出四缸柴油发动机中采用CVT刚性联接曲轴轴系结构。阐述了该新型结构的特征和工作原理,建立了四缸柴油发动机离合式曲轴计算模型和CVT刚性联接曲轴计算模型。通过曲轴前端实验,证明了所建模型和模型参数确定方法的正确性。求解所有计算模型,并对结果进行对比分析。结果表明,CVT刚性联接使曲轴轴系振动波动加大,减振器耗散能增加,各阶共振峰值对应转速低减。对曲轴各拐剪切应力幅度的影响不大,但有高转速工况降低而中低转速剪切应力幅值增加的普遍趋势,CVT端的扭振振幅和剪切应力较大些。综合研究得出结论：非道路车辆低速四缸柴油发动机可以采纳CVT刚性联接曲轴轴系结构。     

Numerical Analysis on Mechanism of the Metal Pushing Type Continuously Variable Transmission

Continuously variable transmissions have attracted a great deal of interest in recent years because they shift with very little shock and offer significant advantages of acceleration performance and fuel economy for automobile.The slide angle is very important physical parameter in belt study. It's magnitude expresses the changing of direction of friction force's and makes the distribution of force very complicated. In this paper,the reason of the slide angle has been discussed. The formulae of wrapping angle relation with slide angle is put forward. The magnitude of slide angle is computed by used the Runge Kutta method in different speed ratios. On the basis of study a new descrete numerical analyse approach is proposed to analysis and calculate the tension and thrust of the key work piece's the metal rings and the metal blocks of the metal pushing type continuously variable transmission respectively under different speed ratios and torque ratios. The research result in this paper can be used to analyse the strength of the metal rings and the metal blocks and improve the load capability of the CVT gearbox. [WT5HZ]     

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]     

Discussion on Direction of Circular Flow of Reversed Return Hot Water System

Aiming at the central mechanical circulated hot water supply system recommended by the current code, the criteria of water flow direction in the pipes of transport and distribution is brought forward based on the hydraulic principle, followed by the analysing with charts of flow directions in the reversed return hot water system consisting of two, three and several vertical pipes in the working conditions of simple return and a little water distributing. There are several directions of circular flow, the only working condition of simple return and single water flow direction which applied in current hydraulic calculation of reversed return hot water supply system is incomplete, certain hydraulic precondition is necessary to ensure circular flow flowing in each vertical pipe as the assumed direction in the course of hydraulic calculation.     

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.     

A CALCULATION OF THE ECCENTRICALLY LOADED BRICKWORK WITH BIAXIAL BENDING IN TERMS OF ULTIMATE STRENGTH DESIGN METHOD

This paper suggests a calculation formula for eccentrically loaded brickwork or column with biaxial bending in terms of ultimate strength design method. The coefficients of the formula, are compiled as design charts so that the formula can be directly used for design of this kind of structural members.