Research And Development On The Test Bench Of Series Hybrid Tractor

As a large agricultural country,the pressure of tradition internal combustion engine tractors on the environment and resource is increasing gradually in China,so,developing electric tractor or hybrid tractor will be an effective way to solve the problem.The power battery for electric tractor can't be developed in short time,and thus,the hybrid tractor becomes the best choice in current stage.It needs to solve a series of key technical problems,such as electric drive,energy storage and management,dynamic parameters matching and so on.Hybrid tractor test bench just provides a practical significance platform for solving those problems.To make the test bench be versatility and scalability and its subject be wider,the design ideas followed the modular design during the developing of hybrid tractor test bench.According to the functional requirement of the test bench,the test bench was divided into six main modules:driver's input module,engine test module,power module,motor control and test module,load simulation module and data acquisition module.Only engine test module,power module and data acquisition module were researched and designed in this paper due to the time and laboratory conditions.The engine test module consisted of 36KW diesel engine,the torque and speed sensor and the fuel consumption sensor,the module is used to test the load operating characteristics of the engine and monitor the energy consumption.The power module was made up by generator,power control cabinet,resistance box,battery and voltage and current sensor.The module's function is to provide power for the bench and monitor the battery' s performance.The data acquisition module was designed to make a virtual control system based on the LabVIEW software platform and related data acquisition equipment.The module was mainly used to collect various sensors' test signal,meanwhile,do some necessary conversion,filtering and operations for those signals,and output the result.In addition,the hybrid vehicle simulation technology was discussed in this paper,and the hybrid tractor's parts and vehicle models were established in Simulation X.The hybrid tractor's dynamic performance in transport operation and plow operation cycle test conditions which built in Simulation X were researched.Conclusions were:(1)The torque outputted increased as the external load increased,and the change of output torque followed external loads.(2)The battery' s output current had a great relationship with external load,the bigger the load,the larger the current.The battery's SOC curve went down almost straight,the larger the load,the faster the curve went,i.e.the larger the curve's slope.(3)When the battery's charge dropped to the lower limit,the engine would step into the work,and the operating speed kept almost the same,but the output current would has a mutation at the moment.Researching on the subject is expect to provide theoretical and technological support for the development of series hybrid tractors' or other types of hybrid vehicles' test bench.