Modernization of the power unit of the 1.4 drawbar category tractors by using a reversible electric machine

BACKGROUND: The technical development of tractor designs features an increase in the consumed power, the use of electric drive units. Therefore, the load on the electric system of a modern tractor constantly increases and exposes the existing systems to excessive load. It is impossible to meet the growing needs of tractors and their systems using conventional generators. OBJECTIVE: Research and development of highly efficient means of ensuring reliable launch of diesel engines of the 1.4 drawbar category tractors and provision of on-board electric power by means of use of starter-generator units with microprocessor control. METHODS: An integrated starter generator can serve as a solution to the problem of increasing power simultaneously with increasing efficiency. With sufficient power in the traction mode (up to 8 kW), the starter generator allows improving the launch and energy characteristics of the tractor’s internal combustion engines. The proposed design of the electric machine is placed between the cylinder block of the internal combustion engine and the tractor clutch. The adopted layout allows transferring significant power in both directions, improves the launch performance of tractor diesel engines, and implements the functions of damping of torsional vibrations of the crankshaft, which significantly reduces engine noise and vibration. RESULTS: Based on the results of the study, the choice of a starter-generator unit (SGU) based on a reversible electric machine is justified in relation to diesel engines of the 1.4 drawbar category tractors, and a scheme for its placement in the clutch housing without changing its basic design is developed. The advantage of the proposed design is the use of electric machines for engine launch, which in this case turns on the electric motor mode and switches to the generator mode during operation, providing the on-board network with electric energy. CONCLUSIONS: The practical value of combining a starter and a generator in a single unit lies in simplification of the design, reduction of manufacturing and assembling costs, which is an advantage in terms of production costs, as well as a replacement to the starting piston engine on some tractors.