Calculation of engine power of agricultural machine hybrid power plant

The article presents the method of determining the necessary engine power of a combined power plant of the tractor according to the specified driving conditions. The relevance of the method consists in the identification of the most appropriate characteristics for a power plant, which will reduce the cost of expensive items. The method is based on the traction and power calculations and the initial data on the tractor’s movement mode. The algorithm for calculation of the required characteristics of the combined power plant was used as the estimated model. As an example, the authors demonstrate the calculations of a combined power plant parameters of parallel circuits for a tractor weighing 4.5 t during the ploughing work with force exerted rating of 1150 kgF. These parameters are comparable to tractor MT382 with a combined power plant and attachments equipment. Along with the calculations the schemes of delivery of energy from the internal combustion engine to the drive wheels are developed in the power plant, energy transmission by mechanical means through a gearbox; energy transmission through the generator, the energy storage and electric motor. The findings showed that for the selected machine the power of the internal combustion engine should be at 51.6 kW, and a traction energy storage needs to store 13 kJ of electricity. Consumption of diesel fuel while the highest performance made up 11,3 l/h. Even given the safety factor, the power of the internal combustion engine with a combined power installation will be less by about 12% compared to diesel tractor. The presented method allows to perform a multivariate modelling in different combinations and relations between the power of the engine, energy reserved by the storage, fuel consumption and the cost of the power plant.