| At present, along with the vehicles operation automation fast development, the automobile automatic transmission is presenting the vigorous development tendency. Now the primarily automatic transmissions are hydraulic mechanical automatic transmission (AT). Continuously Variable Transmission (CVT), and in recent years -- at home and abroad is to make great efforts to study automated mechanical transmission (AMT). particularly the development of automated mechanical transmission. At present, because of the high fuel economy, low emissions and protect the existing manual gearbox production investment merits match the development of the automobile industry requirements. attention by a major automobile manufacturer.However, in the research and development of the electronic control automated mechanical transmission, it also gradually discovered some weaknesses. It decided in principle to shift the process of separation of the clutch first, and then abstract transmission in neutral gear, and then the election irresistible. Shifting clutch engagement finally. That way, when the clutch disengaged, Engine power will not be transmitted to the drive wheel to the vehicle running, until the clutch re-engagement, Therefore, the process of a shift of power transmission interrupted, it will have to reduce vehicle speed, a long shift time, having an adverse impact on the acceleration of the vehicle and comfort. In order to make full use of the advantage of automated mechanical transmission, and eliminate the shortcomings of power interrupted in its shifting, a structure of a double-clutch automatic transmission came into existence. This automatic transmission has become the focus of attention of many car manufacturers. The advantage of Double Clutch Transmission is reflected in both of improve the performance of the vehicles and reduce the production costs automatic transmission.1. in the process of Double Clutch Transmission Shift, there is no power failure, the shift did not have a pronounced slowdown. Moreover, it shortened the shifting time, usually two clutch switch time only from 0.3 to 0.4 seconds. So would not be felt crew cab, which has greatly enhanced the shifting comfort, ensure that the vehicle is a good dynamic and shifting characteristics. In addition, due to double-clutch automatic transmission specific internal structure and unique function, it has better fuel economy than traditional transmission. And, because of the improved control, and shorten time-shift, and so on vehicle fuel consumption and emissions have been improved.2. As in the original double-clutch automatic transmission is based on the traditional automated manual transmission. so simple to achieve a structurally complex structure parallel axis rotation axis (planetary gear) automatic transmission results , but is more compact and less costly. Moreover, in the clutch disengagement, gear advance engaged, we can have more speed synchronous time, Synchronizer can also switch to the original presentation, and its structure more simple, the cost is far below AT, CVT. In addition, it can make full use of existing production equipment manual transmission, a small increase in production equipment can be. production continuity, which is very good and very suitable for the existing manual gearbox production plant upgrades to the automatic transmission.As the bridge between the ECU (software) and the manipulate organization (hardware), the electro-hydraulic system is very important to realize the transmission performance target. This paper did some research on the electro-hydraulic, the structure, the principle of manipulate organization and the oil-way of hydraulic system, gived a deeply study on the controlled components (electro-hydraulic valve), the main contents are as follows: 1.I introduced the development history and currently application, presented the problems need to be resolved and the development trend of DCT, especially explained the emphases and significance of the research , at last, definitely bringed forward the main content and significance of the research in this paper.2. particularly introduced the structure, shift and drive principle of the DCT by disassembling the whole transmission and anatomization to the key elements.3. I made a map of the oil-way hydraulic system in the electro-hydraulic system of DCT, analyzed its realization mode, work process and principle. Based on this, established a Clutch Pressure Control System mathematical model, and give a simulation analysis. From the analysis result, we know that the system model can basically reflect the actual work conditions of hydraulic control system. This provide the theoretical basis for the design and the development of the hydraulic control system.4. given a deeply research on the key components (electro-hydraulic valve), including the mechanical structure, the work principle and the characteristic analysis. By utilizing the Matlab/Simulink simulated the control pressure characteristic of the HSV (high speed valve) under the different carrier wave frequency and the input duty conditions, the response characteristics of the proportional pressure valve in the frequency field. The results show that the higher of the frequency, the smaller pressure pulse output, but the smaller scope of duty cycle control. This result have theoretical directive significance to the actual control of the shifting process in DCT.5. according to the practical electro-hydraulic control valve, we designed the test valve body and had experiment on the electro-hydraulic control valve in the multifunctional hydraulic test-bed. From this we got the high speed response characteristics, the no-loaded flux characteristics and the control characteristics between the output pressure and electrical signal duty of the HSV, the control characteristics between the control pressure and the input current, finally, we contrasted the simulation and the trial results by data processing. The paper did a more thorough study on the Double Clutch Transmission structure, the hydraulic Circuit system of electro-hydraulic control system, Clutch pressure control systems and electro-hydraulic control valve. These will help with the design of electro-hydraulic control system for the development of control strategies of DCT.
|
PDF Full Text Request