Contamination of the intake air of internal combustion engines of motor vehicles

The paper presents the composition of atmospheric air as a mixture of gases that make up the solid and variable components, and the definitions of air pollutants are referenced. Gaseous and solid pollutants (dust) of the atmospheric air have been defined. Dusts were divided according to various criteria and their properties were given. Exemplary courses of immission of the fraction of solid particles are given, indicating a strong dependence of the immission on the seasons, days of the week and day and night. The sources and characteristics of artificial and natural pollutants in the atmospheric air are presented. It has been shown that the main sources of anthropogenic pollution in addition to industry and the automotive industry. Cars are a source of gaseous and particulate pollutants PM, and they also emit pollution from brake and clutch lining wear, as well as from tire and road wear. The main sources of natural air pollution were discussed, including volcanic eruptions, fires in landfills, forests, steppes and sand storms, as well as mineral dust (road dust) carried from the ground by vehicles. The properties of road dust are discussed: chemical and fractional composition, density, dust concentration in the air. It has been shown that the two basic components of the dust, silica and corundum, whose share in dust reaches 95%, also have the highest hardness, which may have a decisive influence on the wear of engine components. Various valuesof dust concentration in the air were presented depending on the type and condition of the ground and the conditions of use of vehicles. Keywords: mechanical engineering, internal combustion engines, air pollution sources, road dust

Application of meshless methods to modeling of pistol bullets

The paper presents an analysis of applicability of two meshless methods to the modeling of pistol bullets on the example of a 9 mm Parabellum. The studies included the following methods: SPH and SPG. The results of computer simulations were confronted with ballistic test results in terms of shape-dimensional compliance of the deformed projectile. The relative error of the projectile diameter was 15 and 17% for the SPG and SPH methods, respectively. The deformation form for the SPH method deviated from the ballistic test results, while the SPG method faithfully reproduced the shape of the deformed projectile. Keywords: mechanical engineering, impact simulation, pistol bullet, SPH, SPG

The potential of HVO as a highly reactive biofuel in dual fuel systems

In times of increased efforts to reduce greenhouse gas emissions to the atmosphere from the automotive sector, engineers and researchers are finding effective solutions to achieve this goal. The reduction of carbon dioxide emissions can be achieved by increasing the efficiency of the internal combustion engine or reducing the carbon content in the fuel burned. The combination of both of these assumptions can be the use of modern dual-fuel systems for diesel engines in which the pilot dose of highly reactive fuel is hydrotreated vegetable oil (HVO), which is an ecological substitute for diesel oil. The topic of the use of HVO as a pilot fuel is empirically unexplored, however the available information on it indicates the validity of such applications.

Review of the method design and additive manufacturing of gears

Additive manufacturing technology is one of the main components of the fourth industrial revolution known as Industry 4.0. Over the last decades, the increase in the dynamics of the development of this technology manifests itself in the form of a wide spectrum of implementations of the methods in the production processes of many elements. This paper presents the latest achievements in the production of gears where the additive technologies have been applied with the use of polymers and metallic materials. The most frequently used methods in this field were indicated, as well as problems related to geometric accuracy or fatigue life of elements manufactured with the use of the methods mentioned. In addition, future directions of gear design, the implementation of which was possible thanks to the use of AM, as well as the scope of research that should be undertaken in this area in the future, were defined. Keywords: mechanical engineering, manufacturing technologies, additive manufacturing, gears

Modern mine scattering systems

For years, mine weapons have been irreplaceable on the battlefield. Using of fully mechanized mine scattering systems made it possible to reduce the direct exposure of soldiers to the enemy's fire, minimize losses and significantly hasten the work. The article presents a comparative analysis of modern mine scattering systems, as well as outlined further research directions related to this topic. Key words: mine explosive barriers, mine scattering systems, pyrotechnic systems

Respiratory protection ‒ new challenges

The paper characterizes the problem of air pollution with smog. The possibility of SARS-CoV-2 virus transmission on particulate matter and the possibility of infection was analyzed. Individual respiratory protection measures available on the market were analyzed in terms of mass use, taking into account legal and normative requirements. Keywords: personal protective equipment, respiratory protection

Experimental and numerical investigation of Armox 500T armor steel perforation process

This paper presents the results of an experimental and numerical study of the perforation of Armox 500T armoured steel. The plate perforation was performed with a pneumatic gun using three types of penetrators. Sharp, spherical and blunt penetrators were used. The use of different geometries of penetrators causes the process of perforation and destruction of plates in a different state of stress and strain, which leads to the appearance of three basic modes of failure. Numerical analyses of the perforation process have been carried out using the Ls-Dyna computational code with an advanced constitutive model of the material and the integrated failure model. The obtained experimental and numerical results were analysed and compared. The failure shape, the level of plastic deformation and the parameters of stress and strain state were analysed.

Comparative analysis of different types of ballistic barrels used in the ammunition researches

Manufacturers offer different types of ballistic barrels made in according to various standards. The paper presents comparison of three types of ballistic barrels: pressure, velocity and accuracy made according to C.I.P. and NATO EPVAT standards. Projectile velocities in a several measuring points on the flight path and propellant gas pressures in the barrels were measured and compared. The main aim of the article is to discuss whether all types of barrels to conduct most ballistic tests are needed, or whether one, the most universal in a specific caliber is enough. Keywords: mechanical engineering, ballistics, firearm, ammunition researches, ballistic properties

Numerical simulations of temperature fields in the uncooled nozzle of a short-range anti-aircraft rocket engine with an insert in the critical section made of various materials

The paper presents numerical simulations of transient heat conduction in the uncooled nozzle of a short-range anti-aircraft rocket engine. The calculations were made for the configuration of the nozzle with an insert in the critical section made of various materials. The inserts used were: POCO graphite, Al2O3 ceramics, ZrO2-3Y2O3 ceramics. For comparison, numerical simulations of the heat transfer in a nozzle made entirely of St 45 steel, the melting point of which is 1700K, were also carried out. The engine's working time was in the order of 3 s. Numerical simulations were performed using the COMSOL program. The calculation results are given in the form of temperature dependence and heat flux density as a function of time in the critical cross-section. Keywords: non-cooled nozzle, rocket engine, temperature field

Analysis of the possibility of using rubber track systems in high-speed engineering machines. Part II. Technical limitations

The article presents problems and indicates limitations affecting the possibility of using rubber tracks in high-speed engineering machines. On the basis of the conducted analyzes, it was also indicated how to shape the running gear in such a way as to improve the working abilities of machines and minimize the disadvantages of rubber track systems. Keywords: mechanical engineering, elastomer tracks, running gear, high-speed engineering machines