Appropriate assessment of the technical condition of internal combustion engines allows determining optimal values for standards of their technical operation, adjusting the parameters of maintenance and repair process operations, and, as a result, reducing the cost of their effective operation. The article is devoted to the use of the Bayes algorithm for assessing the technical condition of internal combustion engines. This algorithm allows using statistical data on repair and maintenance of internal combustion engines, wherein the missing information is determined by the dynamic systems modeling method. The choice of transitional functions of constituent elements of internal combustion engines as diagnostic parameters increases the reliability of obtained results.

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The article is devoted to determinе the parameters of the equivalent torsional scheme of the crankshaft of automotive internal combustion engines. The parameters that depend on the design features of the studied engines include the number and moments of inertia of the motor masses, the stiffness of the shaft sections and their length. Currently used methods are based on empirical data and require their identification for each specific model of the engine under study. To improve the adequacy of the data obtained, it is necessary to conduct fullscale tests of the crankshafts for stiffness. Modeling the spatial structure of the crankshaft by finite elements with further determination of the studied parameters, although it facilitates the task, requires subsequent mandatory verification of the model used. To unify the calculation methods and reduce their complexity, it is proposed to consider the elastic-deformable section of the crankshaft, taking into account the geometric parameters. The accuracy of the results obtained depends on the curve equations describing the elastic deformation surface of the crankshaft transition sections. A preliminary evaluation of the crankshaft parameters can be performed on a piecewise linear surface. Reducing the sampling step increases the accuracy of the results. In the same way, we can take into account such design parameters of the crankshaft as the overlap of the necks, the presence of cavities inside the main and connecting rod necks. The proposed method can be used for automate crankshaft calculations of modern automotive internal combustion engines.

In the article theoretical preconditions of a description of dynamics of manoeuvrability of machine-tractor, aggregates with a wheeled-tracked mover are considered. For a machine-tractor aggregate with half-tracked progress theoretical formulas of determination of an actual turning radius, the moment of resistance of turn and torque for rotation are obtained. The theoretical preconditions are confirmed by experimental research of the manoeuvrability of the machine-tractor aggregate with the tractor on a halftracked progress, made as the experimental sample. The dependences of the turn coefficient and the resistance coefficient of the turn are obtained, and the correlation coefficients and their significance have confirmed the existence of a stable connection between the changing parameter and the response function. Proceeding from theoretical and experimental research, it is possible to draw a conclusion that the manoeuvrability of the tractor with a wheeled-crawler mover does not concede to the tractor in the basic execution.

Currently, methods of direct measurement of design parameters of technical condition are used to determine the remaining life of the engine. This requires complete or partial disassembly of the engine, which implies its decommissioning and subsequent placement on repair sites. The main argument in favor of such methods is the reliability of the results obtained, although this increases the labor intensity and cost of this process. The article proposes a method for non-selective evaluation of the residual life of the engine by the transient functions of its systems. The estimated parameters are the transient functions for fuel consumption, air consumption, and crankshaft speed. Quantitative indicators for transient functions are the intensity of changes in the selected parameters when the load is applied. Depending on the technical condition of the internal combustion engine, they have a high, medium and low level. To make a final decision about the technical condition of the engine, the Bayes algorithm on conditional probabilities is used. In case of an unfavorable combination of factors, this algorithm allows to assess the need for work to restore the engine resource with a certain probability. To improve the adequacy of the results obtained, it is necessary to use statistical data that reflect the relationship between the design parameters of the technical condition and the engine running time. The dependence of the selected diagnostic parameters on the technical condition of the engine is reflected in regression equations. Increasing the sample size of available data increases the accuracy of the diagnosis.