Сельскохозяйственные машины и технологии (Dec 2020)
Research of Tractor Power Unit with Electric Drive Parameters
Abstract
The author showed that it was possible to reduce the exhaust gases toxicity and increase tractors effi ciency using an electric power unit to implement traction. The effi ciency of modern electric motors was at its peak of 96 percent, compared to 45 for a diesel engine. He emphasized that this parameter for modern sources of electrical energy was 85-90 percent, which opened up opportunities for the implementation of an electric tractor.(Research purpose) To present the general concept of an electric drive power unit for a tractor of a small traction class and to evaluate its parameters as a fi rst approximation.(Materials and methods) For the tractor’s electric drive lithium-ion batteries were chosen as a source of electrical energy, showing the best characteristics of energy intensity – 432-864 kilojoule per kilogram with a unit cost of 4200-17400 rubles per kilogram. During the analyses of the power unit drive types, a D-120 diesel engine with a power of 20 kilowatt, a DC electric motor and an asynchronous motor with similar parameters were studied. The VTZ-2032 tractor with a nominal tractive eff ort of 600 Newtons when working on stubble was taken as the basis for the calculation.(Results and discussion) The author determined the best indicators of the electric drive by the power characteristics fullness in the gears with a decrease in unit costs per kWh from 24 to 15-16 rubles.(Conclusions) The most effi cient engine was determined – a brushless DC electric motor. The author calculated that the specifi c cost of its energy was 1.5-1.8 times less than that of a diesel engine, and amounted to 15-27 rubles per kilowatt-hour with a maximum effi ciency of 95 percent. It was found that lithium-ion batteries would be the optimal solution for powering the electric drive. They were distinguished by a high specifi c energy consumption – 432-864 kilojoule per kilogram – and a low price per energy unit, amounting to 5-45 rubles per kilojoule.
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