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The battery electric vehicle (BEV) equipped with automatic mechanical transmission (AMT) can realize gear-shifting automatically based on the optimal shift schedule and thereby gains higher economy and dynamics performances as well as easy drivability. As one of electronic control systems in BEV, the AMT control system takes charge of drivetrain control and plays an important role. However, nowadays the development of electronic control systems in automobile industry is facing a variety of challenges which mainly arise from complex functional requirements and market pressure, and it's the same to the development of AMT control system. This paper presents a multi-layered and modular design approach for the development of AMT control system in a battery electric bus. The multi-layered design approach divides system into two high-level layers, each of which is then divided into a number of low-level layers.

Starting control takes an important role in the system of Automated Mechanical Transmission (AMT); clutch engagement control is the key of it. For the purpose to improving the starting performance of AMT, this paper develops the relation between clutch engaging speed and starting jerk, the relation between engine rotate speed and the friction work in starting process. According to the relations, a starting control strategy of keeping the engine rotate speed constant is putted forward in this paper. The main idea of the strategy is to keep the engine run at a lower rotating speed and don't make it flameout through controlling clutch engagement distance and clutch engagement speed in starting process. Based on the strategy, the clutch control map figures which individually correspond with throttle opening, engine rotate speed and difference between clutch master and slave plate rotate speed are built.

The paper introduces an on-board fault diagnosis strategy based on analytical redundancy suit for automated mechanical transmission (AMT). Through experiment and theory analysis an identified engine model, a gear box model and a dry clutch model controlled by hydraulic actuators are respectively established. The information redundancy in the local models of the power train and the structure logic relations among the assemblages is used to detect and diagnose the fault in the sensors, the actuators and the unit assemblages of the AMT system. The method has been used in the AMT control system developed for the SVWSANTANA2000.

According to the structural features and working characteristics of the dry clutch, this study focuses on the factors that affect the performance and life of the dry clutch. The temperature rise caused by the clutch slipping was proved as the key factor. Dynamics model of the powertrain for the dry clutch in launching process was established, and friction work generated during the launching process was simulated and calculated. Based on the basic theory of heat transfer, this paper defined the boundary conditions of the temperature field and the finite element model for the dry clutch was built. The transient temperature field of the friction disk, temperature field changes under the frequent starting conditions and the effects of friction material on temperature rise were analyzed, and measures were proposed to reduce the temperature of dry clutch from its design, use and control.

This paper defines the shifting quality evaluation index in detail for DCT (Dual Clutch Transmission) from the perspective of control. The vehicle model for DCT is built using MATLAB / Simulink tools, including the models of driver, load, controller, engine, clutch, transmission (synchronizer), actuators, and vehicle dynamics model. And then a control quality evaluation system is designed. The AHP (Analytic Hierarchy Process) is used to determine weights of the control quality evaluation index and the shifting quality control objectives through the co-simulation of vehicle system model and evaluation system, namely expected control range of each evaluation index, which provides reference and guidance for shifting control strategy and control algorithm of DCT.

For the purpose of lessening fuel consumption, engine noise, shift jerk and clutch friction work in the shift process of Automatic Mechanical Transmission (AMT), a fuzzy-bang bang dual mode control strategy for engine rotate speed is put forward in this paper, which takes the advantages of time optimal control and fuzzy control. The combined control strategy is applied to the shift process control of AMT test minibus named SC6350 and proved to be successful by the experimental results.

Hydraulic retarders have been widely used in heavy-duty vehicles because of its advantages such as large braking torque and long operating hours. They can be used instead of service brakes in non-emergency braking conditions and can also reduce frequency and time of driver’s actions in braking process, thereby minimizing heat-related problems. In order to accurately produce braking torque needed for the vehicle in time by using hydraulic retarder, which enable the vehicle to travel stably and safely during downhill driving, aiming at the constant-speed function of hydraulic retarder, the research of constant-speed control method is conducted in this paper. The structure and working principle of hydraulic retarder is introduced and the dynamic characteristic is analyzed. And the theoretical model of vehicle and hydraulic retarder are established based on dynamic analysis of the vehicle downhill driving.

The coordination of engine will influence the starting and shifting quality of AMT. Heretofore, the study on this aspect is mainly limited to the engine torque control. But for the difficulty of installing torque sensor, just open loop control is adopted, so that the effects don't be satisfactory. This paper puts forward the strategy of engine constant speed control in starting and shifting process, based on the view of kinematics and dynamics. The main idea is that the target speed of engine is constituted according to the different throttle opening, and the deviation between the target speed and the actual speed will be limited through clutch control and fuel injection control in starting and shifting process, which not only greatly reduce the work of slipping and prolong the life of the clutch, but also reduce the fuel consumption and the noise, improve the shift quality in starting and shifting process.

Starting control has become a troublesome issue in the developing field of the control system for heavy-duty trucks, due to the complexity of vehicle driving and the variability of driver's intention. The too fast clutch engagement may result in serious impact, influence on the comfort and fatigue life, and even the engine flameout, while the too slow clutch engagement may lead to long time of friction, the increased temperature, and accelerated wear of friction pair, as well as influence on the power performance and fatigue life[1]. Therefore, the key technique of starting control is clutch engagement control, for which the fuzzy PID based optimization of starting control for AMT clutch is proposed, with the pneumatic AMT clutch of heavy-duty trucks as the research object.

The battery electric vehicles (BEVs) equipped with automated manual transmission (AMT) can realize gear-shift automatically and show many advantages in terms of reduction of fuel consumption and improvement of driving comfort and shifting quality. This paper focuses on the gear-shift control strategy for a clutchless AMT in a battery electric bus. Compared with the traditional ICE vehicles, the studied battery electric bus has the different powertrain structure, which consequently requires a different gear-shift strategy. First, the so-called clutchless AMT means that the clutch usually used in the conventional AMT vehicles is removed. Second, the synchronizer within the transmission is omitted and that means only the sleeves are employed to accomplish engagement of gears. In order to find the key factors that affect gear-shift operation of AMT in battery electric bus, the several gear-shift phases including “Gear Release”, “Synchronization”, and “Gear Engagement” are modeled.

With the work medium of automatic transmission fluid (ATF), torque converter (TC) functions perfect performances such as smooth start, torque amplification, and the peak load restraint, and these properties makes the TC most suitable for off-road vehicles. An idea on the integration of TC and synchromesh gear box with their respective advantages is explored and introduced in this paper; here the system is named as Hydrodynamic Synchromesh Automated Transmission (HSAT). An automated control system makes the gear box as an automated manual transmission (AMT). HSAT takes TC as the starting device and accomplish shift process through AMT. The flow field optimized TC structure and the match calculation among the three parts of engine, TC and synchromesh gearbox; made this powertrain system has a good performance and the ability to reduce the fuel consumption.

Gear-shift process of automatic transmission (AT) can be achieved with hydraulic control system which operates clutches or brakes' engagement or disengagement. According to the state of engagement elements, gear-shift process can be divided into torque phase and inertia phase. This article analyses gear-shift process of automatic transmission with the lever analogy and got the variation of the transmission's output torque. Then, the control principle of clutch to clutch shift is studied. This article takes power on up shift as study example and minimum of transmission output torque fluctuations during shifting as control target. Then this article analysis two control principles including inertia phase engine & transmission integrated control principle and entire shift process engine & transmission integrated control principle.

The shifting process always activates some changes of noise quality for its transient characteristics, especially for non-powered-shift transmissions, with which the power from engine is intermitted during the shifting period, such as Manual Transmission (MT) and Automated Manual Transmission (AMT). This type of noise change should have a very close relationship with the status of engine directly. But the essential reasons and how to estimate the noise have not been explored before. Therefore there is no clear understanding upon it and no formal methods yet described in the literature. The present study focuses on the phenomenon and makes effort to build reasonable research methods based on vehicles equipped with AMT. Furthermore, the metrics for assessing the noise has been developed with several different experiments and Support Vector Machines (SVMs) technique.

Improvement of shift quality evaluation has become more prevalent over the past few years in the development of automatic transmission electronic control system. For the problems of the subjective shift quality evaluation that subjectivity is too strong, the standard cannot be unified and the definition of the objective evaluation index is not clear at present, this paper studies on the methods of objective evaluation of shift quality based on the multi-hierarchical grey relational analysis. Firstly, objective evaluation index system is constructed based on physical quantities, such as the engine speed, the longitudinal acceleration of the vehicle and so on, which broadens the scope of the traditional objective evaluation index further.

This investigation presents a methodology to develop and optimize shift process control strategy to improve shift quality as perceived by drivers during power-on upshift events for Dual Cultch Transmission (DCT) vehicles. As part of the first study, the main factors affecting shift quality during shifting process under typical working conditions are analyzed. And taking the power-on upshift as example, dynamic model of DCT shifting process is build. An Integrated control strategy is proposed for power-on upshift, which during torque phase slipping revolving speed controller is adapted to harmonically control two clutches power switching process, and during Inertial phase engine torque is regulated to synchronize with the value of target gear while holding the oncoming clutch pressure. Oncoming clutch oil pressure gradient in torque phase and engine torque reducing target decrement in inertial phase are chosen as controlled quantity.

The thermal management system of the water medium retarder using engine coolant (water and ethylene glycol) as transmission medium, omits oil-water heat exchanger in the structure. When the hydraulic retarder is operated, the valve is connected with the retarder and water pump, and then the engine coolant enters the working chamber. The kinetic energy of the vehicle is converted into internal energy of the coolant, and the heat is discharged to the external environment through the engine thermal management system. The braking torque of the water medium hydraulic retarder is determined by the water medium flow rate in the working chamber. The smaller the valve opening degree, the greater the braking torque and the faster the heating transmission fluid. Small valve opening is not conducive to the loss of heat. It will affect the normal working of the engine and hydraulic retarder.

Hydraulic retarders are extensively used in heavy-duty vehicles because of their advantages, such as their large braking torque and long continuous operating hours. They can reduce the vehicle velocity by converting the kinetic energy of a traveling vehicle to the thermal energy of the working fluid. The water medium retarder is a new type of hydraulic retarder with the characteristics of high power density and simple structure. It uses the engine's coolant as the working medium, and the heat is directly taken away by the vehicle cooling system. Therefore, the heavy-duty vehicle can achieve long-term continuous braking during the downhill process. One of the main functions of water medium retarder is driving downhill at a constant speed which determines whether the vehicle drives stably and safely. Therefore, studying the constant-speed control strategy during downhill driving is particularly important.

With more and more countries proposing timetables for stopping selling of fuel vehicles, China has also issued a “dual-slope” policy. As electric vehicles are the most promising new energy vehicle, which is worth researching. The integration and control of the motor and gearbox have gradually become a hot research topic due to low cost with better performance. This paper takes an electric vehicle equipped with permanent magnet synchronous motor and two-gear automatic transmission without synchronizer and clutch as the research object.

Selection of gearshift point plays an important role in the field of automatic transmission technology, which directly affects the vehicle dynamic and economic performance, etc. In order to designing optimal gearshift strategies for conventional passenger vehicles equipped with stepped automatic transmission, in this paper, the vehicle power demand was defined under different environment, different driving intention and different vehicle operating conditions. Dynamic programming (DP) method is used to solve the optimal static gearshift decision sequence based on the simplified model of powertrain system. The drivability is respected by imposing an inequality constraint on the power reserve limit and the fuel economy is the objective function. Considering the change of vehicle additional load and road slope, the gearshift strategy based on power reserve is proposed.

In a traditional shift control strategy, the gear range is selected based on the throttle opening and the vehicle speed. The disadvantage of two-parameter based system is that the shift map is lack of adaptability in certain special conditions. The driving environment and the true intentions of the drivers are not fully taken into account by the shift control system. Therefore, improving the feasibility of the shift control strategy for the true intentions of the driver and driving environment is of great significance. Under braking conditions, Automatic transmission shift map with two parameters is unable to use engine braking effectively, which affects the drivability and safety of vehicles greatly. This paper presents a newly developed shift control strategy under braking conditions. First of all, the necessity of engine braking was analyzed.