| The secondary regulating hydraulic transmission has wide application in the future for its abilities of energy recycle and reuse. The secondary regulating hydraulic transmission usually works in constant pressure network, belongs to pressure coupling system, so its small range of pressure change limits the energy recycle and reuse. So the domestic and foreign researchers put forward two ways, one is by use of hydraulic transformer, the other is to let the secondary regulating hydraulic transmission work in variable pressure network.In the paper, to solve the problems that the constant pressure network's small range of pressure change limits the energy recycle and reuse, based on the secondary adjusting hydraulic transmission of constant pressure network, a variable pressure network was presented, its theory basis and key technology was studied. The main work is focused on structure, parameters and characteristics of the vane secondary element and its hydraulic transformer, new energy storage and release device, control method of the secondary adjusting hydraulic transmission and performance of variable pressure network. Some achievements were made during key technology, math modeling, performance simulation and experiments.Comparing the variable pressure network with the constant pressure network of the secondary adjusting hydraulic transmission, the flow coupling variable pressure network is used for single load or parallel load in the same work state, the pressure coupling constant pressure network is used for parallel load in different work state. The energy-saving principle of the variable pressure network of the secondary regulating hydraulic transmission was discussed, three system energy recycle ways were presented, ie. speed control, torque control and power control, and comparing these three ways.The research on the structure, parameters and performance of the single and dual acting vane secondary element and its hydraulic transformer and its variable control method and program was developed, its several variable devices and whole structure was designed. Simulation on speed and torque, flow feature of the single and dual acting vane secondary element was developed.To overcome the influence of load change to the energy recycle and reuse the variable pressure network of the secondary regulating hydraulic transmission, a new control method of energy storage and release was presented. The structure of energy storage and release was provided, a new energy storage and release was designed, it is made of two or more energy storage loops, and each loop was controllable. The energy storage volume, the top and bottom pressure and pressure distribution of every loop were designed.To overcome the nonlinear and uncertainty of secondary regulating hydraulic transmission, two typ controllers have been designed. One is based on Hamiltonian functional method, for performance simulation of bus hybrid power system or excavator bucket lifting device; the other is for performance test of bus hybrid power system, combing the neural network, fuzzy control and expert control to design an multi-mode intelligent controller. It changed the controller effectively according to the work state based on the online coordination control method. A knowledge rule of is established according to the design ideas of intelligent coordination system, the controller issued different commands to control the system online by comparing the set the maximum and minimum error threshold, the maximum and minimum error rate threshold with the feedback error and error rate. The intelligent hybrid control method was used for the parallel secondary regulating hybrid powertrain of bus, and simulated it.The application of Hamiltonian functional method is extended to the secondary regulating hydraulic transmission system. With construction of the system's Hamiltonian form, the H-controller has been designed via Hamiltonian function method. By Hamiltonian function method, the dynamic characteristics of the system have been improved significantly, with strong anti-interference ability and good robustness. The system has no overshoot, fast response and small static error.The above key technology was used to the parallel secondary regulating hybrid system of bus; the control method, main elements and parameters were designed; the open model and close model of the elements and system was established, simulations on speed control, torque control and power control of the system was developed. The way of bus brake energy recovery, conversion and storage and reuse was discussed. Recovery efficiency of inertial energy on torque control was the highest, the braking time is the shortest, and the next is speed control, then the power control.The above key technology was used to the excavator, a secondary regulating hydraulic lifting device for excavator bucket was designed, its working process and energy saving mechanism was studied, math mode of lifting and failing for the hydraulic lifting device was established, and study on its working performance was developed.Based on the secondary regulating hydraulic transmission experimental plat, simulations on speed control, torque control and power control of the parallel secondary regulating hybrid system of bus was developed, the experimental results match the simulation results. The control method was also used to the Changjiang CJ6920G4C10H type bus, the prototypes based on the control theory was produced, and its experiments for oil consumption and fuel-efficiency was carried out.The paper shows the energy saving character of the variable pressure network of the secondary regulating hydraulic transmission, the rules of energy recovery, conversion and storage and reuse was discussed, the basis theoretical system for the variable pressure network of the secondary regulating hydraulic transmission was established, it lays a foundation for developing independent intellectual property secondary element and its hydraulic transformer and its wide use. |
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