Conceptual design of economic hybrid vehicle system using clutchless geared smart transmission

Most hybrid vehicles employ the continuously variable transmission (CVT or eCVT) currently as their choice of the transmissions. Recently, an automated geared transmission (AGT) or dual clutch transmission (DCT) is being tried for some hybrid vehicles for the better fuel economy than the CVT hybrid. However, this AGT or DCT is using automated clutches which require the hydraulic power in addition to the slippage in the clutch plate invoking some energy loss as well as wear. Also, they require a motor with significant power to match to the engine power. The clutchless geared smart transmission (CGST) has no clutch and the clutch function is performed by a planetary gear system controlled by a motor-generator. The hybrid vehicles proposed here using CGST may have some merits in durability, fuel efficiency, and cost since they do not have clutches. The motor used for the clutch function can be also working for power merge with the engine in propelling the vehicle. The proposed hybrid system can be either mild hybrid or full hybrid by adopting a different capacity of battery with much smaller motor-generator due to the planetary gear system compared to the other type hybrid vehicles. In this study, the prospects of newly proposed CGST hybrid system are examined in practical aspects compared with AGT hybrid or DCT hybrid systems.     

Torque coordinating robust control of shifting process for dry dual clutch transmission equipped in a hybrid car

For a hybrid car equipped with dual clutch transmission (DCT), the coordination control problems of clutches and power sources are investigated while taking full advantage of the integrated starter generator motor's fast response speed and high accuracy (speed and torque). First, a dynamic model of the shifting process is established, the vehicle acceleration is quantified according to the intentions of the driver, and the torque transmitted by clutches is calculated based on the designed disengaging principle during the torque phase. Next, a robust H_∞ controller is designed to ensure speed synchronisation despite the existence of model uncertainties, measurement noise, and engine torque lag. The engine torque lag and measurement noise are used as external disturbances to initially modify the output torque of the power source. Additionally, during the torque switch phase, the torque of the power sources is smoothly transitioned to the driver's demanded torque. Finally, the torque of the power sources is further distributed based on the optimisation of system efficiency, and the throttle opening of the engine is constrained to avoid sharp torque variations. The simulation results verify that the proposed control strategies effectively address the problem of coordinating control of clutches and power sources, establishing a foundation for the application of DCT in hybrid cars.     

变速箱空挡开关故障原因分析

在整车中,变速箱空挡开关输出信号是很重要的一种信号输出手段。它作为一种安全保护装置,一般装配于变速箱的操纵机构上。这种装置保证了只有在变速器挂空档时,发动机才能够起动,从而避免驾驶员由于挂档起动发动机,而脚又不踩离合器踏板造成事故。本文对变速箱空挡开关的工作原理进行说明,同时对比较常见的故障模式进行分析,寻求可行的提高措施。     

Adaptive control of the shifting process in automatic transmissions

This paper focuses on the way of keeping shift quality of automatic transmissions consistent in mass production and with mileage accumulation. We investigate the main factors influencing the consistency of shift quality. Test results show that the torque to pressure (T2P) and pressure to current (P2I) characteristics of shifting elements are easily affected. A simulation model of an 8-speed automatic transmission is established to simulate the dynamic process of clutch-to-clutch shift. Simulation results demonstrate that the change of T2P and P2I characteristics has a significant influence on shift quality. In order to compensate for the influences, we develop two adaptive control strategies, i.e., the adaptive control strategies for torque phase and inertia phase. They make use of the measured speed information and time information to evaluate shift quality. Then the control parameters are tuned to adapt to the change of T2P and P2I characteristics. Vehicle tests verify that the developed adaptive control strategies are effective to keep shift quality consistent in mass production and with mileage accumulation.     

浅析变速箱壳体设计与工艺结合

文章基于汽车自动变速箱壳体的设计开发流程,对自动变速箱壳体的设计进行全面系统的分析和讨论。在变速箱壳体的设计过程中,结合系统开发、拓扑优化、强度校核、工艺分析、加工分析和装配分析等几个方面,总结出变速箱壳体在设计开发过程中所需要关注的方面。     

Kinematics of a smart variable caster mechanism for a vehicle steerable wheel

The lateral force of a tyre is a function of the sideslip and camber angles. The camber angle can provide a significant effect on the stability of a vehicle by increasing or adjusting the required lateral force to keep the vehicle on the road. To control the camber angle and hence, the lateral force of each tyre, we can use the caster angle of the wheel. We introduce a possible variable and controllable caster angle ? in order to adjust the camber angle when the sideslip angle cannot be changed. As long as the left and right wheels are steering together according to a kinematic condition, such as Ackerman, the sideslip angle of the inner wheel cannot be increased independently to alter the reduced lateral force because of weight transfer and reduction of the normal load F _z . A variable caster mechanism can adjust the caster angle of the wheels to achieve their top capacity and maximise the lateral force, when needed. Such a system would potentially increase the safety, stability, and maneuverability of the vehicles. Using the screw theory, this paper will examine the kinematics of a variable caster and present the required mathematical equation to calculate the camber angle as a function of suspension mechanism parameters and other relevant variables. Having a steered wheel about a tilted steering axis will change the position and orientation of the wheel with respect to the body of the car. This paper provides the required kinematics of such a suspension and extracts the equations in special practical situations. The analysis is for an ideal situation in which we substitute the tyre with its equivalent disc at the tyre plane.     

软土地基冻结过程的热传导分析

土冻结过程同时进行着热传导和湿迁移；软土地基的存在使得路基路面体内的温度、湿度、温度梯度和湿度梯度的变化不同于常规的水冻问题。分析热传导规律和水分运动规律，对确定软土地基处理的原则和方法有重要意义。     

Development of a new manual transmission

New 6-speed and 5-speed manual transmissions have been developed for a few FF cars that match up with the high revolutions and high power of the new i-VTEC [1] engine. The development objectives were to improve fuel efficiency and enable smoother transmission shiftings as well as to achieve a compact design. In order to achieve these targets, the transmission employs technologies to reduce friction, weight and transmission length, and also to create a large capacity synchronizer system enabling high rotational speed.     

飞机牵引车静压和液力传动的特点分析

飞机牵引车正广泛趋于采用静压传动和液力传动技术，两者在飞机牵引车中相互渗透，相互影响，但两者的工作原理和结构却安全不同，用于主机传动系的匹配计算方法也完全不同。从飞机牵引车的匹配特点出发，分析了两种传动的工作特点，通过对匹配原理的分析，为飞机牵引车的开发、设计、选配提供了依据和方法。     

一种矿用车专用变速器设计

结合矿用车工况,提出矿用车变速器的开发要求,作为设计开发输入,据此设计了一种专用车变速器,并详细介绍了该变速器的结构和工作原理。     

传动比对纯电动客车的能耗影响分析

通过AVL-Cruise搭建了纯电动城市客车仿真计算模型,结合某车型相关参数,并根据其在中国典型城市公交循环工况下仿真结果[1],计算了电机和后桥主减速器的平均工作效率,分析了不同主减速器传动比对整车能耗的影响。     

高速公路用户接入层传输网络的设计方案分析

对高速公路用户接入层的传输网络需求进行了分析，对各种传输制式进行了比较，提出了高速公路用户接入层传输网络的最佳解决方案。     

一种铅酸蓄电池电压平衡仪电路设计

针对铅酸蓄电池组在浮充电过程中,单体电池的端电压会出现不平衡的问题,分析了其产生的原因,阐述了该仪器的电路组成结构、工作原理、技术指标,以及自动控制主程序流程图。该仪器具有自动循环每个电池的端电压,自动均衡充电,实时显示实时评估电池容量、储存、记录和打印当月电池组工作情况与PC通讯。是功能比较完善,智能化比较高的蓄电池测量维护设备。     

Analysis of the effect of cold start on fuel economy of gasoline automatic transmission vehicle

FTP75 driving cycle is used in many countries for evaluation of vehicle fuel economy. FTP75 has 3 phases, where the Phase 1 and the Phase 3 have a same velocity profile, but the Phase1, which is known as cold start phase, shows lower fuel efficiency than the Phase 3. In order to analyze the difference of fuel economy between Phase 1 and Phase 3, vehicle tests are performed. The test results show that the differences of fuel economy is ranging from 3.9% to 18.5%. The factors of the difference of fuel economy for gasoline automatic transmission vehicles are analyzed in this research. The key factors affecting the difference of fuel economy are engine friction loss, torque converter loss and accessory loss. The quantitative analysis of these factors is performed.     

Control of a hydraulically actuated continuously variable transmission

Vehicular drivelines with hierarchical powertrain control require good component controller tracking, enabling the main controller to reach the desired goals. This paper focuses on the development of a transmission ratio controller for a hydraulically actuated metal push-belt continuously variable transmission (CVT), using models for the mechanical and the hydraulic part of the CVT. The controller consists of an anti-windup PID feedback part with linearizing weighting and a setpoint feedforward. Physical constraints on the system, especially with respect to the hydraulic pressures, are accounted for using a feedforward part to eliminate their undesired effects on the ratio. The total ratio controller guarantees that one clamping pressure setpoint is minimal, avoiding belt slip, while the other is raised above the minimum level to enable shifting. This approach has potential for improving the efficiency of the CVT, compared to non-model based ratio controllers. Vehicle experiments show that adequate tracking is obtained together with good robustness against actuator saturation. The largest deviations from the ratio setpoint are caused by actuator pressure saturation. It is further revealed that all feedforward and compensator terms in the controller have a beneficial effect on minimizing the tracking error.     

Control of a hydraulically actuated continuously variable transmission

Vehicular drivelines with hierarchical powertrain control require good component controller tracking, enabling the main controller to reach the desired goals. This paper focuses on the development of a transmission ratio controller for a hydraulically actuated metal push-belt continuously variable transmission (CVT), using models for the mechanical and the hydraulic part of the CVT. The controller consists of an anti-windup PID feedback part with linearizing weighting and a setpoint feedforward. Physical constraints on the system, especially with respect to the hydraulic pressures, are accounted for using a feedforward part to eliminate their undesired effects on the ratio. The total ratio controller guarantees that one clamping pressure setpoint is minimal, avoiding belt slip, while the other is raised above the minimum level to enable shifting. This approach has potential for improving the efficiency of the CVT, compared to non-model based ratio controllers. Vehicle experiments show that adequate tracking is obtained together with good robustness against actuator saturation. The largest deviations from the ratio setpoint are caused by actuator pressure saturation. It is further revealed that all feedforward and compensator terms in the controller have a beneficial effect on minimizing the tracking error.     

HW1500系双副轴变速箱两副轴扭矩分配浅析

以建模的试验方式分析了HW1500系双副轴变速箱两副轴档位齿轮相对偏转角度不同时,两副轴分担扭矩的分配情况,利用数据分析得出了两副轴档位齿轮相对偏转角度越小,两副轴齿轮分担的扭矩越接近各50%,并给出在实际生产加工中的合理化建议。     

Analysis of axial behavior of three-piece oil control ring

It is considered that the reduction of oil control ring tension is a major problem in reducing the friction-loss of internal combustion engines. The authors have successfully developed a calculating method for the axial behavior prediction of a three piece type oil control ring as a method used in reduction of lube-oil consumption when a lower tension ring is used. By means of this method, the authors found a reduction of lube-oil consumption could be expected by optimizing design parameters of the oil ring, the tension and the seating tab angle of expander-spacer, and the gas pressure on the 3rd land.     

考虑土体侧胀性的路堤沉降分析

从土的侧胀性出发，运用有限单元法，研究了土的侧胀性对路堤沉降的影响，研究结果表明：在路堤的沉降计算中，土的侧胀性起着十分重要的作用，采用非线性本构模型时尤为显著，为此在路堤设计时应慎重考虑。