Design And Simulation Of A New Hybrid Power Tractor Drive System

As the world’s large agricultural country,agriculture in China has a special status.Now the world is facing energy shortages,environmental pollution and climate anomalies.Developing energy-saving tractor has great significance of reducing environmental pollution and sustainable development of energy.Electric tractor’s Development is limited by the battery technology,hybrid tractor breakthrough the limit of battery.In addition with the tractor implements market steady growth,design of a new type of hybrid electric tractor drive system not only can well satisfy the demands of the market and also in line with the concept of sustainable development.At first this paper proposes four new hybrid electric tractor drive system,and according to the advantages and disadvantages of each kind of new driving system are discussed and analyzed,by comparing them this paper select the system which use a power distribution to the engine through the transfer case to drive the rear power output shaft,and use the wheel hub motor to drive the wheel.In the design of driving system of hybrid power tractor,this paper proposed dynamic performance evaluation index system and economic performance evaluation index.This paper established the theoretical model of engine,generator,battery and motor.Then design and matching parameter of the new hybrid tractor cdrive system.This paper also designed the transfer case and a wheel side reducer.According to the new hybrid electric tractor drive system,this paper use the simulation X hybrid simulation software platform to established the ’components model and vehicle model,and respectively on new hybrid electric tractor drive the power performance and the economic performance of the system is simulated,and draws the following conclusions:(1)Hub motor’s torque increased with the load increased,while the speed decreased.(2)Tractor’s maximum grade ability is 34 degrees,with a speed of 7km.(3)The acceleration time of hybrid tractor is gradually decreased with the reduced set speed.(4)When the lithium battery SOC is set to 20%～80%,and set the speed of the tractor at 40km/h in good road,20 km/h in the field road,7 km/h in the field during the ploughing operation and 5 km/h in the field during the rotary tillage operation,the battery working time is 1.5h,0.6h,0.5h and 1.25h.This paper build the test platform,test results are as follows:(1)the output characteristic curve of the hub motor is approximately hyperbolic,and with the hub motor speed increases,the torque decreased.The wheel hub motor has a large speed range and the characteristics of low-speed and large-torque,which can meet the requirements of the tractor’s power performance;(2)When the engine at the rated speed,under the state of no-load loss torque distribution around the 14N·m,the energy loss at around 2.2kW.When the engine speed is stabilized at 1500rpm the rate of fuel consumption of the engine is decreasing with the load increases,when the engine is running at a power of 36kW,it has the lowest fuel consumption rate of 224g/kWh.Researching on the subject is expecting to provide a theoretical basis and technical support for the following research and develop hybrid electric tractor drive system.