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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.

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.

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.

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 shift quality is one of the most important factors that affect the vehicle performances of comfort, ride and drivability for vehicles equipped with dual clutch transmission (DCT). Assessing the shift quality first and then optimizing shift control strategy and algorithm by the guidance of assessment results to improve the vehicle performance is a useful idea for the development of DCT and other types of automatic transmissions. This paper defines the shift quality assessment criteria in detail for DCT from the control point of view. A shift quality assessment system and a DCT vehicle model used for validation of assessment system are built with MATLAB/Simulink tools. Through the co-simulation of DCT vehicle model and assessment system, the shift quality control objectives, namely the expected control range of each assessment criterion, are determined, which provide reference and guidance for the optimization of DCT shift control.

A good starting quality for AMT (Automated Manual Transmission) vehicles means that the vehicle is started quickly and smoothly on the premise of protecting powertrain system. The starting quality is closely related to the vehicle ride comfort and the service life of powertrain system. In order to improve the starting quality, a good idea is evaluating the starting process firstly and then optimizing the control strategy. However this method has two problems to be solved. The first one is how to define a series of objective criterions to judge the starting quality, and the other is how to select a suitable algorithm to optimize the starting control. This paper focuses on the starting quality assessment and optimization of AMT vehicles. First, the assessment criterions for starting quality are defined in detail from the control point of view and a corresponding assessment system is created.

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.

Drag torque in multi-plate wet clutch consumes engine energy, but also has significant affect on synchronization process during shifting. The mathematical models of drag torque and shift synchronization process were established, and the results carried out by Matlab/Simulink simulation were compared with experiment results as well. It is demonstrated that the models are correct and accurate. The influences of friction pair gap in multi-plate wet clutch, cooling oil flow and properties of cooling oil under different temperature etc. on drag torque, shift synchronization time and energy were analyzed. The conclusions have certain guiding significance to the multi-plate wet clutch theoretical study and structural design as well as transmission system matching.

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.