No abstract

This paper discusses warm-up processes for the hydraulic system components of road construction machinery using mathematical and physical simulations. The efficiency of these processes is governed by warm-up and cool-down rates of the hydraulic actuator components. It studies how various hydraulic system components interface as they warm up. The general task is to estimate the dynamic behavior of the components and loops comprising such components and the entire warm-upsystem. The models of the transient heat flow process of the warm-up system are based on the heat balance equation of the flowing medium (of the heat transfer fluid – a hydraulic fluid) within the control volume. For experimental verification, the hydraulic actuator components warm-up modes using the warmed-up hydraulic fluid from the hydraulic tank have been tested on the hydraulic test bench that we developed. The example of consecutive warm-up of the hydraulic system components is given. Based on this, after the experimental findings were processed, correlation coefficients for different warm-up modes and types of relationships between the hydraulic actuator component temperatures and their warm-up times were determined.

Abstract-In the conditions of autonomous functioning of special equipment, there is a need to use its internal sources. This can be accomplished using a heat recovery system of the internal combustion engine. For this purpose, the authors suggest a heat accumulator. The mathematical modelling of the thermal state of the heat accumulator in the cooling stage is done. The main factors affecting the cooling time of the thermal accumulator are the thickness of the insulation of the heat accumulator, the mass of coolant, coolant temperature, air temperature, wind speed. The authors also developed a mathematical model of the cooling process of the heat accumulator in a general way. It is presented in graphical form, which makes it easier to determine the time of cooling the heat accumulator in the process of its designing. For automatic calculation, an algorithm has been developed and implemented in the program to determine the dimensionless temperature and criterion Bio.Keywords -operation, modeling of the thermal accumulator, thermal preparation, heat transfer, heat recovery system, low negative temperatures.