| Summary: | Relocation or beating of the piston occurs due to the action of lateral force in the crank mechanism, which leads to an increase in friction forces and shock loads in conjunction with the sleeve. Ultimately, this affects the operation of the engine, its noise, vibration and leads to intensive wear of the piston skirt. Therefore, the study of issues related to improving the reliability of the engine of transport and technological vehicles is an urgent task of technical operation. The aim of the work is to increase the reliability of the engine of transport-technological machines by reducing vibration during its operation. The article discusses a method that allows to reduce shock loads in the piston-cylinder coupling at a low crankshaft rotational speed at maximum torque, which is typical for the main engine modes of a transport-technological and road-building machine. It is proposed that under maximum load conditions with a minimum speed of rotation, the value of the total force when passing through the top dead center at the end of the compression stroke be equal to zero. In order for the gas pressure force at the top dead center to be equal to the inertia force of the translationally moving masses, it is recommended that the engine be tuned to change the valve timing during a compression stroke, i.e. increase the angle of delay in closing the intake valve. In confirmation of the above, a calculation was made to determine the angle of delay in closing the intake valve using the example of the YaMZ-65202.10 engine. To fulfill the equality of the gas pressure force and the inertia force at the top dead center, the value of the real engine compression ratio was found, which was 12.5. Next, the angle of the inlet valve closing lag is determined for this mode, which is calculated to be 540 crankshaft rotation after bottom dead center (according to the technical characteristics of this engine, this value is 480). The calculated data may be the initial parameters for the calibration of the program embedded in the electronic control unit of the transport and technological machine.
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