International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

Increases in road traffic lead to the expansion of areas of the acoustic discomfort, and the noises from vehicles acquire social importance. The noise as a set of sounds is characterized qualitatively and quantitatively by two main indicators: the sound pressure or intensity level, which have different effect on the human body. In addition, in terms of the effect on the human body, the prefence is given to the noise equivavlent level. The study of the noise equivalent level can be carried out in two ways. The first one consists in fact that at a given moment of time, at any point in space, there are summarized the noise level or sound energy intensity from all radiation sources, but another way implies summarizing the selected sound energy sources during a certain time period. So, in order to determine the noise equivalent level of one vehicle during that time period, which is required for passing a certain section, it is necessary to know those laws, which characterize traffic conditions and the calculated changes of the noise level in these conditions.

When the internal combustion engine operates there are arising forces acting on the supporting elements, and by both value and sign they represent variable forces. They vary depending on time, depend significantly on load conditions of engine and are characterized by different vibro-frequency energies. These energies are unevenly distributed due to fact that the engine design comprises the elements having inertial, flexural and dissipative properties, frequency characteristics of which often vary within a wide range. The paper describes the method for determining frequency characteristic of vibro-energy transferred to the frame by introducing the vibro-energy transfer coefficient, which allows for determining frequency characteristics of vibro-energy transferred to the frame, on the basis of which, in turn, it becomes possible to determine efficiency of bearing shoes.

The paper dwells on peculiarities of operation of engine running on gaseous fuel that envisages the influence of the period of impeding spontaneous combustion on the operation of engine with the dependence on dosing of fuse. Simultaneously, there is considered the influence of changeability of the air-excess coefficient on the engine load when using the different gaseous fuels, as well as its influence on the efficient operation of engine, improvement of ecological and economic parameters, with account for improving geometrical parameters of engine. There are given the analysis and comparison of the efficient characteristics of the ideal cycle of diesel engine when running on liquid and gaseous fuel.

An internal combustion engine is considered as a material body, which characterized by inertial, elastic and dissipation properties, which are impacted from various forces. Oscillatory motion of a material body occurs in accordance with spectral characteristics of force and frequency responses of the system. The outer surface of the engine generates acoustic energy and causes mechanical noises.

The paper dwells on determining acoustic energy in accordance with the acoustical radiation rate if the radiation coefficient of the object observed is known. Also, the sound of the engine is presented as a sum of its separate acoustic powers, and there is determined the acoustic radiation coefficient of the engine for the entire surface, by using the acoustic radiation coefficient of each surface. Simultaneously, there is determined the vibro-energy distribution in the engine design, the assessment of which is made by means of the energy-transfer coefficient, which generates the frequency responses of vibro-acoustic parameters.

The carburation process in modern diesel engines practically begins with the moment of fuel injection in into the cylinder, and ends at the same time as the combustion process. The improvement and development of the carburation process depend on the injection parameters, particularly on: the motion of charge in the combustion chamber; fuel properties; combustion chamber sizes; a surface temperature; interdependent motion of charge and fuel. With a view to carburation in diesel engines, we obtain a nonhomogeneous mixture in diesel engines. First of all, the internal carburation process cannot ensure uniform distribution of the injected fuel’s steam and air. Besides, the improvement of carburation process is impeded by fact that as a result of the combustion process development there occur the fuel injection and carburation that increases that amount of fuel, which is burnt in the expansion line. All this causes increasing thermal heat losses and growing amount of toxic substances in exhaust emissions. Also, the improvement and efficiency largely depends on the length of self-ignition impeding period that directly defines the engine’s dynamic magnification factor. The paper dwells also on the possibilities of partial eradication of negative phenomena and increasing the engine’s efficiency, as well as reducing toxicity. In the engine’s intake system, the electric injector is inserted, by means of which, at the beginning of the intake process, there is carried out the injection of a certain amount of fuel in front of the inlet valve, and together with the air coming into the cylinder it creates the mixture, which occurs during the filling and compression process, and at the end of the compression process, the main amount of fuel is atomized by means of basic injector.

By the end of the compression process, until the fuel is atomized from the basic injector, we have the depleted, but almost homogenous mixture, and therefore, this mixture is uniformly distributed in the combustion chamber. At the same time, the primary oxides, to a certain extent, are created for starting combustion. Immediately after the fuel atomizing from the basic injector, we will obtain the mixture required for combustion, and the combustion process begins earlier than during the process of the creation of a standard mixture, and this means that the length of self-ignition impeding period reduces, and consequently the efficiency goes up, and the amount of soot in exhaust emissions is reduced.