Ensuring stable load mode of internal combustion engine of an agricultural machine through the use of a combined power plant

One of the ways to improve the performance of an agricultural machine’s power plant is to stabilize the load mode of its internal combustion engine. The article considers the calculation methodology of the characteristics of the engine as part of a combined electromechanical power plant (CEP) of an agricultural machine. The proposed methodology allows to determine the possible power of the primary energy source of the CEP - the internal combustion engine and the efficiency of the agricultural machine as a whole. The ways of load mode stabilization using serial and parallel power transmission schemes in a power plant are presented. The authors used the following data as initial, the machine operation cycle with changes in its speed or load mode, the mass of the machine, energy characteristics of transmission, electrical machines, voltage converters, electric energy storage and internal combustion engine. The balance of the machine’s energy consumption throughout the entire cycle is estimated during the calculationprocess. Next, the amount of energy passing from the engine to the working body of the machine is determined for each of the considered chains: mechanical, electrical and storage. The advantage of this method is that it is possible to obtain various combinations of characteristics of the internal combustion engine and other elements of the CEP, i.e. one can set any value of the electric storage capacity and get the necessary power of the internal combustion engine and fuel consumption. This method also allows to determine the most appropriate type of CEP for the specified operating conditions. For example, the article presents the calculation results for a 4.5- ton tractor. Due to the reduction of load surges, the internal combustion engine power for the work performed was reduced from 60 to 11 kW. As a consequence of the load mode stabilization and the elimination of inefficient operating modes, the specific indicators of fuel consumption by the agricultural machine are reduced.