Dry Dual Clutch Research Articles

Dry Dual Clutch Transmission’ Optimal and Coordinating Launching Control with Two Clutches Based on the Minimum Principle

For the self-developed five-speed dry dual clutch transmission(DCT), the coordinating and optimal control is proposed based on minimum principle to solve the problems of launching with two clutches. In the slipping phase, minimum principle and improved engine constant speed control are adopted to obtain the optimal clutch and engine torque and their rotating speed with the minimum jerk intensity and friction work as optimization indexes. Besides, the separation conditions of non-target gear clutch and the clutches' torque distributing relations are determined by the launching control targets. In the torque switching phase, engine torque is converted to the driver's demand level. Besides, the launching control strategies are simulated under the different launching conditions on the Matlab/Simulink. Simulation results validate that the proposed control strategies based on the minimum principle can effectively obtain an excellent launching quality, reflect the driver's launching intention and extend the life span of twin clutches.The clutch optimal principles are then transformed into clutch position principles and the closed-loop control of clutch position is verified in test platform of clutch actuator as a result of achieving a preferable tracking performance.

Sliding Mode Variable Structure Control and Real-Time Optimization of Dry Dual Clutch Transmission during the Vehicle’s Launch

In order to reflect driving intention adequately and improve the launch performance of vehicle equipped with five-speed dry dual clutch transmission (DCT), the issue of coordinating control between engine and clutch is researched, which is based on the DCT and prototype car developed independently. Four-degree-of-freedom (DOF) launch dynamics equations are established. Taking advantage of predictive control and genetic algorithm, target tracing curves of engine speed and vehicle velocity are optimally specified. Sliding mode variable structure (SMVS) control strategy is designed to track these curves. The rapid prototyping experiment and test are, respectively, conducted on the DCT test bench and in the chassis dynamometer. Results show that the designed SMVS control strategy not only effectively embodies the driver’s intention but also has strong robustness to the vehicle parameter’s variations.

Fuzzy Determination of Target Shifting Time and Torque Control of Shifting Phase for Dry Dual Clutch Transmission

Based on the independently developed five-speed dry dual clutch transmission (DDCT), the paper proposes the torque coordinating control strategy between engine and two clutches, which obtains engine speed and clutch transferred torque in the shifting process, adequately reflecting the driver intention and improving the shifting quality. Five-degree-of-freedom (DOF) shifting dynamics model of DDCT with single intermediate shaft is firstly established according to its physical characteristics. Then the quantitative control objectives of the shifting process are presented. The fuzzy decision of shifting time and the model-based torque coordinating control strategy are proposed and also verified by simulating under different driving intentions in up-/downshifting processes with the DCT model established on the MATLAB/Simulink. Simulation results validate that the shifting control algorithm proposed in this paper can not only meet the shifting quality requirements, but also adapt to the various shifting intentions, having a strong robustness.

Starting sliding mode variable structure that coordinates the control and real-time optimization of dry dual clutch transmissions

This paper researches the coordination of control between an engine and clutch at the system level to adequately reflect a driver’s intention and improve the starting performance of a vehicle equipped with a dry dual clutch transmission (DCT). Four-degree-of-freedom (DOF) starting dynamic equations are established for a dry DCT with a single intermediate shaft, and a two-DOF model of the sliding friction process and a single-DOF in-gear model of stable operation are obtained after simplifying these equations. Taking advantage of predictive control and a genetic algorithm, target tracing curves of the engine’s speed and the vehicle’s velocity are optimally specified online, and the starting sliding mode variable structure (SMVS) coordinating control strategy is designed to track these curves. The starting performance of a prototype car equipped with a dry DCT is simulated under different starting cases on the MATLAB/Simulink software platform. The simulation results show that the designed SMVS coordinating controller not only embodies driver intention and effectively improves the dry DCT car’s starting performance but is also highly robust when subjected to variations in the vehicle parameters.

The Displacement Control of Clutch Actuator Based on NNPC

A clutch actuator system of dry dual clutch transmission was presented in this paper, and clutch displacement intelligent control arithmetic based on NNPC(Neuro Network Predictive Control) was designed to realize accurate control of clutch displacement. The accurate mathematical model and simulation model based on Matlab/Simulink of proportional flow valve were established.The simulation was carried out and the intelligent control system was verified by experiment. The rusults showed that the clutch intelligent control algorithm with NNPC had good adaptive ability and high precision. It could meet the requirements of the clutch displacement control for dry dual clutch transmission.

Experimental Characterization and Modeling of Dry Dual Clutch Thermal Expansion Effects

Experimental Characterization and Modeling of Dry Dual Clutch Thermal Expansion Effects

Fuzzy Time Decision and Model-based Torque Coordinating Control of Shifting Process for Dry Dual Clutch Transmission

Based on the five-speed dry dual clutch transmission(DCT) which have been independently developed,the issue of torque coordinating control between engine and twin clutches is been discussed from the system level in order to adequately reflect the driver’s intension and improve the shift quality of DCT,calculation formulas of engine speed and clutch delivered torque during the shifting process are been induced also.Considering the characteristic of physical configuration,five degrees-of-freedom(DOF) shifting dynamics equations of DCT are been established,after simplifying two-DOF model in the stage of slip-friction and one-DOF model in the stage of in-gear stable operation are been respectively attained.According to the requirements of the shift quality,the quantitative control objectives of shifting process are been proposed.Based on the analysis of torque and speed characteristics of engine and twin clutches during the shifting process,the fuzzy time decision and the model-based torque coordinating control strategy are been produced.Simulation model of DCT shifting control is been established on the Matlab/Simulink software platform,upshifting process and downshifting process are been simulated and analyzed under different driving intension.Real vehicle chassis dynamometer test has also been done.Simulation and experiment results show that the proposed model-based torque coordinating control strategy can not only effectively reflects the driver shift intention and improve the shift quality of DCT,but also be adaptable to the various shifting conditions and has strong robustness.

Research on Design Theory and Experimental Validation of Dry Friction Automotive Clutch Based on Failure Mechanism

As a key component of vehicle, automotive clutch remained high failure rate, meanwhile, with the development of engine and vehicle technology, functional characteristics of automotive clutch such as comfort, durability and reliability demanded much higher. Objective of the study is to establish the correspondence relationship between failures and design theory and experimental methods, reduce failure rate and improve product reliability. In order to create a system approach of problem-solving, we collected clutch failure information and classified according to clutch functional requirements and mechanical design principles. Then we used RCA (root cause analysis) and quality management tools to analyze the cause of failures, used QFD (quality function development) and DFMEA (design failure mode effects analysis) method to protocol the corresponding control measures to improve the existing design theory and experimental methods. The study also can be applied to more complex systems such as dry dual clutch module and dual-mass flywheel damper.

Analysis of Dry Dual Clutch Transmission Technology

Dual clutch transmission (DCT) combines the advantages of AMT and AT. This paper selects a certain type of dry DCT as the study object. The structure and working principle are introduced. A shift dynamic model is established to analyse the five phases of shift process. The oil line diagram of the electro-hydraulic control system is provided, and then the characteristics of the proportional solenoid valves which are critical control components of DCT are studied. The analysis results provide theoretical basis and guidance for the design and development for DCT.

Design of Test Rigs for a Dry Dual Clutch and its Electromechanical Actuator

Dual Clutch Transmissions with dry electromechanically actuated clutches have emerged on the market recently. In order to provide their favorable operation in terms of the clutch torque control, it is very important to have a good knowledge on the system behavior related to the actuator dynamics, the dry friction coefficient behavior, and the thermal dynamics. This paper describes two test rigs developed to support the research work on a dry dual clutch with a leverbased electromechanical actuation system. The first test rig (actuation system test rig) provides a basis for a comprehensive multi-step identification of the actuation system parameters and characterization of the overall system behavior. This test rig includes a modified dual clutch assembly including a built-in sensor for the purpose of direct normal force measurement. The second test rig (transmission test rig) is aimed at providing support for more comprehensive characterization of the actuation system under realistic operating conditions and characterization of the clutch torque transfer dynamics/friction coefficient behavior, thermal dynamics, and wear. Both test rigs are computer controlled and include measurements of all main system variables. Functionality of the test rigs is demonstrated by characteristic experimental results.

Slip Mode Variable Structure Coordinating Control and Real-time Optimization of Launch for Dry Dual Clutch Transmission

Based on the five-speed dry dual clutch transmission(DDCT) which is independently developed,the issue of coordinating control between engine and clutch is investigated from the system level in order to adequately reflect the driver's intention and improve the launch performance of car equipped with DCT,and engine speed and clutch delivered torque in the launch process are quantified and corresponding calculation formulas are derived also.Considering the characteristic of physical configuration,four degrees-of-freedom(DOF) launch dynamics equations of DDCT with single intermediate shaft are established,and two-DOF equations of slip-friction phase and one-DOF equation of in-gear stable operation phase are respectively gotten after carrying on simplification.Utilizing the predictive control thoughts and genetic algorithm,target tracing curves of engine speed and vehicle velocity are specified optimally online,slip mode variable structure(SMVS) servo control strategy of launch is designed to track these curves.Launch performance of prototype car with DCT is simulated under different driving conditions on the Matlab/Simulink software platform.The rapid prototyping experiments of SMVS launch strategy are conducted on the hardware-in-the-loop test bench of DCT control unit,which is built up independently.Simulation and test results illustrate that the proposed servo controller of SMVS not only effectively embodies driver's intention and improves the launch performance of DCT prototype car but also has strong robustness to parameters' variations of car,it can be applied for the launch control of automated mechanical transmission(AMT) in the meantime.

Clutch torque formulation and calibration for dry dual clutch transmissions

This paper focuses on the clutch torque formulation and calibration for dry dual clutch transmissions (DCT). The correlation on the theoretical clutch torque and control parameters is established based on constant friction power and clutch actuator kinematics. An algorithm based on powertrain dynamics is proposed for the calculation of clutch torque during vehicle launch and shift operations. This algorithm uses wheel speed sensor data as input and is capable of determining the clutch torque while both clutches are slipping, thus provides a reliable correlation between clutch torque during real time operations and clutch actuator control variables. The accuracy of the proposed algorithm has been validated by torque measurement in prototype testing on prove ground.

Research on optimal control for dry dual-clutch engagement during launch

A non-linear dynamic model of the passenger car driveline with dual-clutch transmission is proposed by treating the dry dual clutch as a system of multiple rigid bodies for numerical simulation of their engaging behaviours in launch phases. For the synthetic optimal engaging performance and simple optimization procedures, the effects of the friction work, shock intensity, and engine torque are examined and introduced into the objective function. The optimal engagement laws are deduced for the dry dual clutch by finding a compromise between the friction work, shock intensity, and engine torque, based upon the extremum value theorem. Numerical examples are given using the present mathematical modelling for the purpose of comparison of the transient dynamic responses of the dual clutch during engagement in a number of typical working conditions. It is shown that the present control strategy is efficient and promising.

A Systematic Model for Dynamics and Control of Dual Clutch Transmissions

This paper focuses on the dynamic modeling and analysis of dry dual clutch transmissions (DCTs) during vehicle launch and shifts. The system model incorporates the clutch torque control strategies for DCT vehicle launch and shifts. This model is capable of quantitatively analyzing and predicting dual clutch transmission dynamic characteristics and performance metrics, such as launch response and shift patterns, thus providing an analytical tool for DCT torque control and calibration. The model is applied for a test vehicle equipped with a dry dual clutch transmission. The simulation data on vehicle launch and shift dynamic characteristics are highly agreeable to the data obtained on the test vehicle.

The seven-speed dual clutch transmission from Volkswagen

Volkswagen is making two world premieres with the new seven-speed dual clutch DSG transmission. It is both the first seven-speed transmission for front transverse mounting and the first dual clutch transmission with a ‘dry’ dual clutch. The transmission is designed for a maximum torque of 250 Nm and use for vehicles in the compact class as well as, also a world premiere, for vehicles in the small class. As a build feature, the dry dual clutch has considerable benefits for the entire transmission concept. Compared to Volkswagen’s current six-speed dual clutch transmission, it comes with an even higher efficiency rating and therefore makes a significant contribution to reducing fuel consumption and emissions levels in the design of new vehicles.