Aiming at the development of parallel hybrid electric vehicle (PHEV) powertrain, parameter matching and optimization are presented, According to the performance of PHEV, the optimization range of engine, motor, driv...Aiming at the development of parallel hybrid electric vehicle (PHEV) powertrain, parameter matching and optimization are presented, According to the performance of PHEV, the optimization range of engine, motor, driveline gear ratio and battery parameters are determined. And then a two-level optimization problem is formulated based on analytical target cascading (ATC). At the system level, the optimization of the whole vehicle fuel economy is carried out, while the tractive performance is defined as the constraints. The optimized parameters are cascaded to the subsystem as the optimization targets. At the subsystem level, the final drive and transmission design are optimized to make the ratios as close to the targets as possible. The optimization result shows that the fuel economy had improved significantly, while the tractive performance maintains the former level.展开更多
In view of the characteristics of warehouse or freight yard carrying out transfer and loading conditions,the performance parameter matching of the power system of an electric transfer vehicle was studied,and the drivi...In view of the characteristics of warehouse or freight yard carrying out transfer and loading conditions,the performance parameter matching of the power system of an electric transfer vehicle was studied,and the driving motor and power battery of the key components of the vehicle were reasonably selected.Cruise software was used to simulate the loading process of the vehicle.The results show that the performance design of the power system of the electric transport vehicle and its key components is reasonable,meeting the requirements of maximum speed,climbing performance and starting driving performance,and providing a reference and credible basis for the design of the power system of the vehicle.展开更多
By using the weight function method,the matching parameters of the half discrete Hilbert type multiple integral inequality with a non-homogeneous kernel K(n,||x||ρ,m)=G(nλ1||x||ρmλ,2)are discussed,some equivalent ...By using the weight function method,the matching parameters of the half discrete Hilbert type multiple integral inequality with a non-homogeneous kernel K(n,||x||ρ,m)=G(nλ1||x||ρmλ,2)are discussed,some equivalent conditions of the optimal matching parameter are established,and the expression of the optimal constant factor is obtained.Finally,their applications in operator theory are considered.展开更多
In order to improve the stability of the hydraulic balancing circuit,taking a certain type of vehicular radar flip device as the research object,the influence of different wind load,counterbalance valve parameters and...In order to improve the stability of the hydraulic balancing circuit,taking a certain type of vehicular radar flip device as the research object,the influence of different wind load,counterbalance valve parameters and hydraulic pump flow pulsation on the system flip process are simulated and analyzed.Through the force analysis of the flipping device,the total load curve of the flip cylinder is obtained by using MATLAB simulation.The simulation model of balancing circuit and plane flip device are built by AMESim software,and the reasonable parameter matching relationship is obtained by specific simulation analysis.The simulation results show that when the wind load is to the left and decreases,the system runs more stably.When wind load works in the right direction,the load on the piston rod of the hydraulic cylinder decreases but the jitter amplitude increases.At the same time,the stability of the balancing circuit can be effectively improved by properly reducing the damping diameter of the counterbalance valve,setting the pilot ratio to 4∶1 and using the hydraulic pump with small pulsation.The optimized parameter matching relationship can not only meet the requirements of typical system conditions and responses,but also improve the performance of the circuit.展开更多
As an important development direction of pure electric vehicle drive system,the distributed drive system has the advantages of compact structure,high transmission efficiency,and flexible control,but there are some ser...As an important development direction of pure electric vehicle drive system,the distributed drive system has the advantages of compact structure,high transmission efficiency,and flexible control,but there are some serious problems such as high performance requirements to the drive motors,complex control strategies,and poor reliability.To solve these problems,a two motors dual-mode coupling drive system has been developed at first,which not only has the capacity of two-speed gear shifting,but also can automatically switch between the distributed drive and the centralized drive by means of modes change control.So,the performance requirements to the drive motors can be reduced,the problem of abnormal running caused by the fault of unilateral distributed drive systems also can be resolved by replacing the drive mode with centralized drive.Then,the system parameters primary and the optimum matching under the principle of efficiency optimization have been carried out,which makes the drive system achieve predetermined functions and meet the actual demands of different operating statuses.At last,the economic comparison of a pure electric vehicle installation with a dual-mode coupling drive sytem,a single-motor centralized drive system or a dual-motor distributed drive system in the simulation conditions has been completed.Compared with other systems,the driving range of the electric vehicle driven by the designed system is significantly increased,which proves the better efficiency and application value of the system.展开更多
A pure electric vehicle driven by dual motors is taken as the research object and the driving scheme of the driving motor is improved to increase the transmission efficiency of existing electric vehicles.Based on the ...A pure electric vehicle driven by dual motors is taken as the research object and the driving scheme of the driving motor is improved to increase the transmission efficiency of existing electric vehicles.Based on the architecture of the transmission system,we propose vehicle performance parameters and performance indexes of a pure electric vehicle,a time-sharing driving strategy of dual motors.First,the parameters of the battery,motor,and transmission system are matched.Then,the electric vehicle transmission model is built in Amesim and the control strategy is designed in Simulink.With the optimization goal of improving the vehicle’s dynamic performance and driving range,the optimal parameters are determined through analysis.Finally,the characteristics of the motor are tested on the bench.The results show that the energy-saving potential of the timesharing driven double motor is higher,and the driving mileage of the double motor drive is increased by 4%.展开更多
To investigate the effects of matching characteristics of tandem cascade on the performance and flow at large angle of attack, the unsteady numerical simulation has been implemented. The influences of different turnin...To investigate the effects of matching characteristics of tandem cascade on the performance and flow at large angle of attack, the unsteady numerical simulation has been implemented. The influences of different turning angle ratio(TR) and chord length ratio(CR) of two blades and the relative angle of attack of rear blade(Delta) are analyzed. The numerical results indicated that the tandem cascade can obtain overall performance improvement including higher static pressure ratio and lower total pressure loss with the matching parameters in the range of TR=3~5, CR=0.5~1.2, and Delta=-15°~-5°. The separation on the front blade has more prominent impact than that on the rear blade, so the performance improvement of tandem cascade is significantly dependent on the reduction of front-blade separation and loss. Regarding the rear blade, the gap injection effect can periodically control the separation. Temporal and spatial analysis of the flow field shows that the optimal-performance cases generally have much smaller wake loss for both two blades, but the unsteady characteristics of the wake loss is more apparent than that of the poor performance cases.展开更多
The rationality of powertrain parameter design has a significant influence on the traction performance and economic performance of electric tractor.At present,researches on powertrain parameter design mainly focus on ...The rationality of powertrain parameter design has a significant influence on the traction performance and economic performance of electric tractor.At present,researches on powertrain parameter design mainly focus on electric vehicles,and electric agricultural machinery draw much less attention.Therefore,a method of powertrain parameter matching and optimization design for electric tractor was proposed in this paper,which was based on dual-motor coupling drive mode.The particle swarm optimization(PSO)algorithm based on mixed penalty function was used for parameter optimization.Parameter optimization design was programmed using MATLAB.A simulation dynamic model with optimization design variables of electric tractor powertrain was established based on MATLAB/Simulink.Compared with the simulation results before optimization,the objective functions were optimized and the traction performance of electric tractor was improved,which indicated the effectiveness of the proposed method.展开更多
Usually extended two-phase capillary pressures are used in three-phase simulations,because three-phase capillary pressures are not possible or hard to measure.In this work three-phase capillary pressure surfaces are c...Usually extended two-phase capillary pressures are used in three-phase simulations,because three-phase capillary pressures are not possible or hard to measure.In this work three-phase capillary pressure surfaces are created by at pore network model.The input parameters to this network model are found by matching two-phase capillary pressure curves.This matching is done with a slightly modified EnKF routine.Tables with three-phase capillary pressures are created and used as input to flow simulations.展开更多
The air-cycle refrigeration system is widely used in commercial and military aircraft,and its efficiency greatly affects aircraft performance.Nowadays,this system requires a more efficient design and optimization meth...The air-cycle refrigeration system is widely used in commercial and military aircraft,and its efficiency greatly affects aircraft performance.Nowadays,this system requires a more efficient design and optimization method.In this paper,a short-cut optimization method with high efficiency and effectiveness is introduced for both conventional and electric air-cycle refrigeration systems.Based on the system characteristics,a four-layer parameter matching algorithm is designed which avoids computational difficulty caused by simultaneous equations.Fuel penalty is chosen as the objective function of optimization;design variables are reduced based on sensitivity analysis to improve optimization efficiency.The results show that the 3-variable optimization of the conventional air-cycle refrigeration system can obtain almost the same results as the traditional 6-variable optimization in that these two optimizations can both significantly reduce the fuel penalty.However,the computer running time of the 3-variable optimization is much shorter than that of the 6-variable optimization.The optimal fuel penalty of the electric air-cycle refrigeration system is lower than that of the conventional one.This study can provide reference for optimizing the aircycle refrigeration system of aircraft.展开更多
文摘Aiming at the development of parallel hybrid electric vehicle (PHEV) powertrain, parameter matching and optimization are presented, According to the performance of PHEV, the optimization range of engine, motor, driveline gear ratio and battery parameters are determined. And then a two-level optimization problem is formulated based on analytical target cascading (ATC). At the system level, the optimization of the whole vehicle fuel economy is carried out, while the tractive performance is defined as the constraints. The optimized parameters are cascaded to the subsystem as the optimization targets. At the subsystem level, the final drive and transmission design are optimized to make the ratios as close to the targets as possible. The optimization result shows that the fuel economy had improved significantly, while the tractive performance maintains the former level.
文摘In view of the characteristics of warehouse or freight yard carrying out transfer and loading conditions,the performance parameter matching of the power system of an electric transfer vehicle was studied,and the driving motor and power battery of the key components of the vehicle were reasonably selected.Cruise software was used to simulate the loading process of the vehicle.The results show that the performance design of the power system of the electric transport vehicle and its key components is reasonable,meeting the requirements of maximum speed,climbing performance and starting driving performance,and providing a reference and credible basis for the design of the power system of the vehicle.
基金Supported by National Natural Science Foundation of China(Grant No.12071491)Guangzhou Science and Technology Plan Project(Grant No.202102080177).
文摘By using the weight function method,the matching parameters of the half discrete Hilbert type multiple integral inequality with a non-homogeneous kernel K(n,||x||ρ,m)=G(nλ1||x||ρmλ,2)are discussed,some equivalent conditions of the optimal matching parameter are established,and the expression of the optimal constant factor is obtained.Finally,their applications in operator theory are considered.
基金Key Project of Industrial Science and Technology of Shaanxi Province(No.2015GY068)。
文摘In order to improve the stability of the hydraulic balancing circuit,taking a certain type of vehicular radar flip device as the research object,the influence of different wind load,counterbalance valve parameters and hydraulic pump flow pulsation on the system flip process are simulated and analyzed.Through the force analysis of the flipping device,the total load curve of the flip cylinder is obtained by using MATLAB simulation.The simulation model of balancing circuit and plane flip device are built by AMESim software,and the reasonable parameter matching relationship is obtained by specific simulation analysis.The simulation results show that when the wind load is to the left and decreases,the system runs more stably.When wind load works in the right direction,the load on the piston rod of the hydraulic cylinder decreases but the jitter amplitude increases.At the same time,the stability of the balancing circuit can be effectively improved by properly reducing the damping diameter of the counterbalance valve,setting the pilot ratio to 4∶1 and using the hydraulic pump with small pulsation.The optimized parameter matching relationship can not only meet the requirements of typical system conditions and responses,but also improve the performance of the circuit.
基金supported by the National Key Technology R&D Program of the Ministry of Science and Technology(Grant No.2013BAG14B01)the Shandong Provincial Natural Science Foundation of China(Grant No.ZR2012EEL08)China Postdoctoral Science Foundation Funded Project(Grant No.2013M530608)
文摘As an important development direction of pure electric vehicle drive system,the distributed drive system has the advantages of compact structure,high transmission efficiency,and flexible control,but there are some serious problems such as high performance requirements to the drive motors,complex control strategies,and poor reliability.To solve these problems,a two motors dual-mode coupling drive system has been developed at first,which not only has the capacity of two-speed gear shifting,but also can automatically switch between the distributed drive and the centralized drive by means of modes change control.So,the performance requirements to the drive motors can be reduced,the problem of abnormal running caused by the fault of unilateral distributed drive systems also can be resolved by replacing the drive mode with centralized drive.Then,the system parameters primary and the optimum matching under the principle of efficiency optimization have been carried out,which makes the drive system achieve predetermined functions and meet the actual demands of different operating statuses.At last,the economic comparison of a pure electric vehicle installation with a dual-mode coupling drive sytem,a single-motor centralized drive system or a dual-motor distributed drive system in the simulation conditions has been completed.Compared with other systems,the driving range of the electric vehicle driven by the designed system is significantly increased,which proves the better efficiency and application value of the system.
基金Supported by Beijing Institute of Technology Research Fund Program for Young Scholars(3030011181911)the National Natural Science Foundation of China(520020025)。
文摘A pure electric vehicle driven by dual motors is taken as the research object and the driving scheme of the driving motor is improved to increase the transmission efficiency of existing electric vehicles.Based on the architecture of the transmission system,we propose vehicle performance parameters and performance indexes of a pure electric vehicle,a time-sharing driving strategy of dual motors.First,the parameters of the battery,motor,and transmission system are matched.Then,the electric vehicle transmission model is built in Amesim and the control strategy is designed in Simulink.With the optimization goal of improving the vehicle’s dynamic performance and driving range,the optimal parameters are determined through analysis.Finally,the characteristics of the motor are tested on the bench.The results show that the energy-saving potential of the timesharing driven double motor is higher,and the driving mileage of the double motor drive is increased by 4%.
基金supported by the National Natural Science Foundation of China (No. 51506179, No. 11772146)the Aeronautics Power Foundation (No. 6141B090303)
文摘To investigate the effects of matching characteristics of tandem cascade on the performance and flow at large angle of attack, the unsteady numerical simulation has been implemented. The influences of different turning angle ratio(TR) and chord length ratio(CR) of two blades and the relative angle of attack of rear blade(Delta) are analyzed. The numerical results indicated that the tandem cascade can obtain overall performance improvement including higher static pressure ratio and lower total pressure loss with the matching parameters in the range of TR=3~5, CR=0.5~1.2, and Delta=-15°~-5°. The separation on the front blade has more prominent impact than that on the rear blade, so the performance improvement of tandem cascade is significantly dependent on the reduction of front-blade separation and loss. Regarding the rear blade, the gap injection effect can periodically control the separation. Temporal and spatial analysis of the flow field shows that the optimal-performance cases generally have much smaller wake loss for both two blades, but the unsteady characteristics of the wake loss is more apparent than that of the poor performance cases.
基金We acknowledge that this working was financially supported by the Thirteenth Five-Year National Key R&D Plan(2016YFD0701001).
文摘The rationality of powertrain parameter design has a significant influence on the traction performance and economic performance of electric tractor.At present,researches on powertrain parameter design mainly focus on electric vehicles,and electric agricultural machinery draw much less attention.Therefore,a method of powertrain parameter matching and optimization design for electric tractor was proposed in this paper,which was based on dual-motor coupling drive mode.The particle swarm optimization(PSO)algorithm based on mixed penalty function was used for parameter optimization.Parameter optimization design was programmed using MATLAB.A simulation dynamic model with optimization design variables of electric tractor powertrain was established based on MATLAB/Simulink.Compared with the simulation results before optimization,the objective functions were optimized and the traction performance of electric tractor was improved,which indicated the effectiveness of the proposed method.
文摘Usually extended two-phase capillary pressures are used in three-phase simulations,because three-phase capillary pressures are not possible or hard to measure.In this work three-phase capillary pressure surfaces are created by at pore network model.The input parameters to this network model are found by matching two-phase capillary pressure curves.This matching is done with a slightly modified EnKF routine.Tables with three-phase capillary pressures are created and used as input to flow simulations.
基金the financial supports from Pre-research Project of National Defense FoundationNational Natural Science Foundation of China(No.51706232)。
文摘The air-cycle refrigeration system is widely used in commercial and military aircraft,and its efficiency greatly affects aircraft performance.Nowadays,this system requires a more efficient design and optimization method.In this paper,a short-cut optimization method with high efficiency and effectiveness is introduced for both conventional and electric air-cycle refrigeration systems.Based on the system characteristics,a four-layer parameter matching algorithm is designed which avoids computational difficulty caused by simultaneous equations.Fuel penalty is chosen as the objective function of optimization;design variables are reduced based on sensitivity analysis to improve optimization efficiency.The results show that the 3-variable optimization of the conventional air-cycle refrigeration system can obtain almost the same results as the traditional 6-variable optimization in that these two optimizations can both significantly reduce the fuel penalty.However,the computer running time of the 3-variable optimization is much shorter than that of the 6-variable optimization.The optimal fuel penalty of the electric air-cycle refrigeration system is lower than that of the conventional one.This study can provide reference for optimizing the aircycle refrigeration system of aircraft.