Dual Clutch Automatic Transmission Research Articles

Performance Comparison of Pure Electric Vehicles with Two-Speed Transmission and Adaptive Gear Shifting Strategy Design

The two-speed automatic transmission can adjust the drive motor speed of electric vehicles and expand their output torque range. This study proposes a rule-based partitioned gear-shifting strategy for pure electric vehicles equipped with a two-speed dual-clutch transmission, combining economic and dynamic shifting strategies to ensure low energy consumption and strong power. Specifically, fuzzy logic is applied to adaptively modify the partition shifting strategy online, to reduce invalid gearshifts, increase the service life of the transmission, and improve driving comfort. Finally, we compare the economic performance and dynamic performance of pure electric vehicles equipped with a two-speed dual-clutch transmission and a single-speed final drive. The results show that the vehicle equipped with the two-speed dual-clutch transmission has better economic and dynamic performance. In addition, its maximum climbing ability was verified by rig testing. These results prove that the two-speed dual-clutch automatic transmission and the gear-shifting strategy proposed in this study can comprehensively improve the performance of pure electric vehicles.

Predictive ramp shift strategy with dual clutch automatic transmission combined with GPS and electronic database

Predictive ramp shift strategy with dual clutch automatic transmission combined with GPS and electronic database

Predictive ramp shift strategy with dual clutch automatic transmission combined with GPS and electronic database

Predictive ramp shift strategy with dual clutch automatic transmission combined with GPS and electronic database

Mass estimation of ground vehicles based on longitudinal dynamics using IMU and CAN-bus data

This paper considers the problem of real-time estimation of ground vehicle mass, based on longitudinal dynamics. Compared to previous contributions, this work relies on basic data from the vehicle controller area network bus. This allows for application to a very broad range of vehicles, by not using vehicle specific parameters such as current gear indicator and engine torque. The current gear ratio is predicted based on the engine and vehicle speeds. The engine torque is modelled by the mass air flow rate of the engine. The road gradient is estimated with an inertial measurement unit, with fusion of gyroscope and accelerometer using a complementary filter. To handle prolonged dynamic conditions affecting the performance of the filter, compensation of external accelerations is made by use of the vehicle speed from the controller area network bus. The mass is estimated with a recursive least squares filter with forgetting factor. The model is validated experimentally with data obtained from test drives with two different petrol powered passenger cars, equipped with a manual transmission and dual clutch automatic transmission respectively. The test drives consist of various driving conditions with different vehicle loads. The resulting mass estimates are generally good for both vehicles with variations within ±5% of the actual masses.

Reliability Test of Dual-Clutch Automatic Transmission based on Oil Monitoring

In this paper, the reliability test of dual clutch automatic transmission is studied by using oil analysis technology. The performance of dual-clutch automatic transmission oil (DCTF) is evaluated by monitoring the kinematic viscosity, acid value, base number, water content and contamination degree of DCTF, combining with the changing trend of its index. The type and composition of abrasives are determined, and the wear form, cause and degree of friction pairs of transmission are revealed by using oil ferrography analysis technology and Ferrography microscopy, which provides a theoretical basis for the friction design of transmission system.

Study on the Influence of Damping Hole of DCT Complex Valve Body Lubricating Oil on System Dynamic Characteristics

The dual clutch automatic transmission (DCT) technology can realize powerless interruption of the shifting process, and its hydraulic control system is a complex hydraulic valve body. The cooling lubricating oil circuit is very important for the lubrication of the clutch and the adjustment of the transmission oil temperature. This paper mainly analyzed the influence of the damping hole on the dynamic characteristics of the system in the lubricating oil circuit. Based on AMESIM software, the simulation model of the lubrication regulating main valve was established. The influence of the size of the damping hole on the output pressure, the lubrication flow of the output clutch and the lubrication flow of the output gear shaft were analyzed under the flow rate step condition. Combined with the vibration of the system, it was found that the reasonable diameter interval of the damping hole was 1.8∼2.3 mm.

A study on the enhancement of amplitude of DCT measured load spectrum considering time-frequency domain damage characteristics

The indoor enhancement simulation bench test of transmission is an important method of assessment, evaluation and promotion of its performance. On the basis of equivalence between time domain and frequency domain damages, an editing and evaluating method of fatigue damage is proposed based on quantitative damage, with which a real load spectrum measured is edited and concentrated. Through test verification, we find that the editing method of load spectrum proposed preserves the damage characteristics of load spectrum in both time and frequency domains, and the road simulation test with the edited load spectrum can accurately assess the fatigue reliability of dual clutch automatic transmission (DCT) key components within a time period greatly shortened.

A study on the enhancement of amplitude of DCT measured load spectrum considering time-frequency domain damage characteristics

The indoor enhancement simulation bench test of transmission is an important method of assessment, evaluation and promotion of its performance. On the basis of equivalence between time domain and frequency domain damages, an editing and evaluating method of fatigue damage is proposed based on quantitative damage, with which a real load spectrum measured is edited and concentrated. Through test verification, we find that the editing method of load spectrum proposed preserves the damage characteristics of load spectrum in both time and frequency domains, and the road simulation test with the edited load spectrum can accurately assess the fatigue reliability of dual clutch automatic transmission (DCT) key components within a time period greatly shortened.

Development of a engine start control method for P2 hybrid vehicles in launch situation

In this paper, the P2 hybrid system with dual clutch automatic transmission (DCT) is used as the research object, and the process which the vehicle driven by motor alone switch to driven by engine in launch situation is analyzed. Focusing on preventing the wheel driving torque variation caused by motor torque rising instantaneously in the process of engine start, the effective method of let the DCT clutch slip at a desired speed, coordinated control strategy of power source torque to reduce the jerk of the vehicle in different launch situation is proposed. Finally, the strategy is verified through vehicle test, the test results showed that the control strategy proposed in this paper can improve the ride comfort of the vehicle during the driving mode transition process effectively.

The Research on Shift Rule of Double Clutch Transmission

Based on the dual clutch automatic transmission, the shift rule is studied. MTTLAB is used to establish the engine model, the transmission model and the vehicle dynamics model respectively. The input parameters are numerically analyed to analye the shift rules of the vehicle, including the best dynamic shift law and the best fuel economy shift law, the combination of shift law. According to the simulation results, we analysis three indicators which include shift speed and quality and fuel consumption.The acceleration performance of the vehicle is better than that of the economic shift rule when the dynamic shift rule is adopted. When the combined shift rule is adopted, the acceleration performance is changed from the slow to the fast. Economic shift law behave the minimum fuel consumption and the best economic performance, combined shift of the economy followed by the economic shift law, the dynamic law is the worst performance of the economy. The combined shift rule is suitable for vehicles that do not have special power requirements and fuel economy requirements for vehicles or vehicles that travel for a long period of time.

Design and analysis of the Gemini chain system in dual clutch transmission of automobile

Chain drive system is widely used in the conditions of high-speed, overload, variable speed and load. Many studies are focused on the meshing theory and wear characteristics of chain drive system, but system design, analysis, and noise characteristics of the chain drive system are weak. System design and noise characteristic are studied for a new type Gemini chain of dual-clutch automatic transmission. Based on the meshing theory of silent chain, the design parameters of the Gemini chain system are calculated and the mathematical models and dynamic analysis models of the Gemini chain system are established. Dynamic characteristics of the Gemini chain system is simulated and the contact force of plate and pin, plate and sprockets, the chain tension forces, the transmission error and the stress of plates and pins are analyzed. According to the simulation results of the Gemini chain system, the noise experiment about system is carried out. The noise values are tested at different speed and load and spectral characteristics are analyzed. The results of simulation and experimental show that the contact forces of plate and pin, plate and sprockets are smaller than the allowable stress values, the chain tension force is less than ultimate tension and transmission error is limited in 1.2%. The noise values can meet the requirements of industrial design, and it is proved that the design and analysis method of the Gemini chain system is scientific and feasible. The design and test system is built from analysis to test of Gemini chain system. This research presented will provide a corresponding theoretical guidance for the design and dynamic characteristics and noise characteristics of chain drive system.

Pressure Measurement System Design and Controlling Study on the Double-Clutch Automatic Transmission

Dual-clutch automatic transmission with two clutches alternate way to achieve work uninterrupted power shift, showing the precise control of the clutch in the dual clutch automatic transmission is extremely important, From that point the text, the design of a converter based on AD7731 dual clutch automatic transmission pressure measurement system, the analysis in detail the system design and the corresponding interface circuit, the test results show that the pressure measurement system design can be very good to meet the needs of the clutch pressure measurement system

The Study on Signals Control System of Wet Dual-Clutch Automatic Transmission Shift Process

To ensure the dual-clutch automatic transmission shift quality, signals processing is required to be fast and stable. This paper designed a signal real-time monitoring and acquisition system for wet dual-clutch automatic transmission with Stateflow and LabVIEW8.6 development platform based on wet dual-clutch automatic transmission electronic control system. Experimental results show that the system is flexible control and responses fast.

Optimal control of gear hift on wet dual-clutch automatic transmission

Optimal control of gear hift on wet dual-clutch automatic transmission

Hydraulic System Optimization and Dynamic Characteristic Simulation of Double Clutch Transmission

Abstract The article focused on a dual-clutch automatic transmission of its hydraulic system. We can calculate the structure size of each body through theory and practical algorithm. The dynamic simulation model of hydraulic system of dual- clutch automatic transmission was established. Then the dynamic characteristics of the system were simulated. And to analysis the simulation results and test results to see the simulation model can be used with the test results. Analysis of simulation results of DCT hydraulic system pressure and flow, as well as different structural parameters of the hydraulic system.

Design of the Intelligent Compensating Shifting Schedule and Its Application in Dual Clutch Transmission Vehicle

The double parameter shifting schedule (DPSS) of dual clutch automatic transmission (DCT) controled by vehicle speed and engine throttle opening,based on enine torque model,engine fuel model and gear ratios of DCT,is designed.In the hardware-in-loop simulation test,some unreasonable shifting phenoemnons such as frequent shifting in EUDC drive cycle and needless shifting in urgent braking condition are found.The reason of the unreasonable shifting phenoemnon is analyzed,then,the conclusion that the unreasonable shifting is mainly caused by the incorrect operation of the driver is presented,and the unreasonable shifting is hard to be avoided if the DPSS is used.To eliminate the improper shifting under certain driving conditions,an intelligent compensating shift schedule (ICSS) is devised on the basis ofsugenofuzzy logic.The ICSS is composed of the input parameters including throttle opening and its changing rate,output parameters including upshift and downshift compensating ratio,membership function and fuzzy control principle.The downshifting speed at a given throttle opening is obtained from multiplying the corresponding speed inferned from DPSS by the downshift compensating ration inferred from ICSS,but the upshifting speed is obtained from dividing the corresponding speed inferred from DPSS by the upshift compensating ratio inferred from ICSS.The final test results prove the ICSS can eliminate the improper shifting in drive cycle and braking condition,and the fuel economy is also improved.

The synchronizer control strategy for dual clutch automatic transmission based on city drive cycle

Based on vehicle parameters,engine torque and fuel consumption models of the car equipped with dual clutch automatic transmission (DCT),the optimal fuel economy shifting schedule of DCT is designed.According to the characteristic that synchronizers of DCT can be engaged in advance during the shift process,the control schedule of DCT synchronizers is put forward on the basis of the devised shifting schedule,which ensures the synchronizers can be accurately operated.Moreover,the variation characteristic of the speed and accelerator pedal when DCT vehicle drives in city drive cycle is analyzed,then,the specific control method of DCT synchronizers is put forward and the control diagram is described.The control results of DCT synchronizer in ECE+EUDC drive cycle are tested by using hardware in the loop simulation methods(HIL),and the test results indicate every synchronizer can be precisely implemented in city drive cycle and even in some extreme condition such as quickly step ping on or releasing the accelerator pedal,furthermore,the unnecessary engaging and disengaging process can be eliminated,the merits of the control strategy are validated.