Two approaches have been analyzed in the article while calculating indicator work on the basis of its diagram, such as: 1) “Gross” - the complete work generated at the combustion-expansion cycle, minus the compression work (A.S. Orlin, B.S. Stechkin et al.); 2) “Net” - the same complete work, but excluding gas exchange losses (S. Pischinger, I.M. Lenin, etc.). The application of this or that approach gives different values for both the average pressure indicator and the mechanical efficiency. At that, the difference in values may exceed 20%. While calculating the mechanical efficiency with the help of “Gross” indicator work there exists, at least theoretically, the possibility of changing the sign of the amount of loss by friction and pumping losses. This leads to nonsense: η_m > 1. In this connection, the authors invite colleagues and the scientific community to discuss the interpretation of “average indicator pressure” (“Gross” vs “Net”) concept and see if it can be changed when keeping to the European standards. A method has been proposed to determine the frictional losses without indication by scrolling the engine with the gas exchange turned off (for example, by keeping the valves closed). This method gives a more accurate result of the determination of friction losses compared to conventional scrolling. The determination of conventional mechanical losses by the scrolling method was and remains a reliable method of monitoring and evaluating the technical state of the engine. However, this method should be used with great care when determining the average indicator pressure.

Due to the internal combustion engine (ICE) dimension reduction the increase in average effective pressure and power density to the level of about 25 bar and 100 kW/l in modern gasoline ICE with a high supercharging has helped to significantly reduce fuel consumption and the amount of harmful emissions (including CO₂). However, the problems of reliability were aggravated by the abnormal combustion phenomena: detonation, glow ignition, pre-ignition and mega-detonation. Further improvement in the efficiency of the engine due to the increase of boost pressure and the decrease in its dimension significantly depended on the solution of abnormal combustion problems. The article is devoted to a review of the features of different abnormal combustion modes in gasoline ICEs with high supercharging, as well as to the analysis of the effect of constructive and regime factors on these combustion modes and specific solutions aimed at suppressing abnormal combustion. It has been shown that the stiffness of abnormal combustion and the predisposition of the internal combustion engine to it depended on temperature, pressure, homogeneity of end gas, duration of combustion, fuel and oil properties, and contamination of the combustion chamber by combustion products. It was noted that the most critical modes of abnormal combustion were pre-ignition and mega-detonation occurring sporadically when operating at low speeds with a high load, that increased the combustion pressure to 15-40 MPa and were very destructive for the engine. It was shown that an effective method of suppressing abnormal combustion was: the combination of high boost with direct injection of fuel, regulated by a valve drive; recirculation of cooled exhaust gases; complex engine cooling; rapid combustion and accurate calibration. This approach can provide the future downsizing engines with a reliability of operation, avoid abnormal combustion and provide a high power density with an efficiency of 40%.

The flow of exhaust gases containing dispersed particles (“diesel soot”) through porous ceramic structures of the folded type has been considered. It was shown that the total gas-dynamic resistance of the filtering element was determined by three components: the resistance of the input and output channels, the resistance of the porous wall, and the resistance of the dispersed particles layer formed on the wall. The simplified mechanisms of gas-dynamic losses, mathematical models and methods of their engineering calculation were proposed. Also the main criteria for the use of analytical expressions were chosen and a test cycle was carried out, which confirmed the validity of the proposed approaches for calculating the main parameters of the filtering unit: its volume, channel dimensions, surface, filter material structure and the properties of exhaust gases. It was established that the greatest resistance, which mainly determined the periodicity and the regime of filter regeneration, was created by a layer of dispersed particles. The second most important factor was the resistance of the porous wall, the through channels of which were determined by the porosity of the filter material. The most perfect from the point of view of gas dynamics, and, consequently, possessing minimum resistance were input and ouyput channels of filtering element. Such a ranking was purely conditional, as it characterized only the main factors affecting the amount of resistance to the exhaust gas flow, and could be useful while looking for ways and means to reduce the gas-dynamic resistance and choose both a neutralization system structure and the overall layout of the internal combustion engine exhaust gases. The experimental verification showed that the relative error in determining the gas-dynamic resistance did not exceed 20-25%, which made it possible to recommend the proposed model and calculation methods as a tool for designing one of the main elements of modern systems - the filter unit - for neutralizing diesel engines.

The aim of the work is the development of a mathematical motion model of a robotized vehicle of high passability with a partial unloading of the mechanical contact propulsion by means of an air cushion (AC) on the support base. The model will allow one to work out a joint robotic control of these subsystems as robotization implies the existence of algorithms and hardware controls of subsystems. It is assumed that such a complex approach will significantly improve motion stability and control of the vehicle. The developed model is specific as it takes into account the subsystem dynamics influence and the air-cushion creation system features together with the possibility of implementing various methods of controlling vehicle subsystems. The article gives the list of the forces affecting the vehicle and describes the interaction of the contact propulsion unit with the support base. It should be noted that, due to the complexity of the mathematical description of the interaction of the АС creation system with the support base in the driving mode, the interaction of the flexibly protected air-cushion with the support surface will be determined by recalculating the static and tow test results of the existing air-cushion model. Such data have been obtained for an air-cushion vessel model developed at the Central Design Bureau “Neptun” during testing in NIMK TsAGI hydro-channel. The results included the characteristics of an air cushion model (ACM) towing tests on smooth water (aerodynamic resistance, hydrodynamic resistance, impulse air resistance at the entrance to the AC fans, total resistance), and the recovery characteristics of the ACM on the solid and water surfaces.

All-terrain vehicles are designed for traffic in various road and ground conditions, therefore the use of electromechanical transmissions leads to difficulties caused by the increase in their dimensions, weight and reduction of power. An effective solution to this problem is the use of several speed ranges in the transmission. A method for selecting high-speed ranges for a multi-purpose wheeled or tracked vehicle with an electromechanical transmission has been proposed. The expediency of using two ranges in transport vehicles transmission was justified. It was proposed that the choice of ranges was to be based on the purpose of the machine. The two rather different laws of the speed distribution of a transport vehicle were considered. The determination of speed boundaries by these laws was proposed to be made with the help of a statistical approach. At the same time, the average speed was used as a required target indicator in the methodology. The selection of ranges for several perspective wheeled and tracked vehicles was made. Basing on the results obtained and stated in the article, conclusions were drawn to specify the values of the transmission boundaries and the influence of engine power on them.

The distribution of torque onto the driving axles of an all-wheel drive vehicle for special purpose is carried out by a transfer gearbox (TG). To increase the passability of the vehicle, it is necessary for a TG to have a rigid blocking drive to the leading axes. However, in this case, there is a power circulation which leads to unnecessary drive loading, so the design of the TG presupposes a differential. The paper presents a diagram and a mathematical description of the TG, which allows to automatically change the kinematic mismatch magnitude (KMM) to ensure the torque distribution depending on road conditions. This is especially important in case of torque distribution between different types of propulsion: elastic (wheel vehicles) and rigid (caterpillar vehicles). Three variants of torque distribution have been considered. A number of calculations for both non-controlled and controlled KMM have been performed to determine the coupling effect depending on the loading conditions of transmission elements. Simulation movement of a special purpose all-wheel drive vehicle for a given typed cycle was carried out in the conditions of a differentiated type of TG coupling between the elastic propulsion unit inter-axis and the controlled KMM of the elastic and rigid propulsion units. In the course of the calculation results processing, the obtained data of changing the torques onto the leading elements of a different type of propulsion units were subjected to a schematization by the maxima method. Subsequently, the schematized processes were represented as a function of the accumulated frequencies of the repeated cycle amplitudes as: a result of 100 km of run, and a distribution density function of process maxima. A comparative analysis of the structural schemes of transmissions has shown that the use of the power drive with a TG having a mechanism for regulating the magnitude of kinematic mismatch is the most expedient.

The safety of a wheeled vehicle movement (vehicle, tractor, motorcycle, etc.) depends on the braking system, the main components of which are brake mechanisms. In modern wheeled vehicle brake systems both disc and drum brakes are used, depending on the purpose and the operating conditions. As most of the passenger vehicles and motorcycles are operated in good road conditions and the production of which is many times greater than of all other machines they are generally equipped with disc brakes on all wheels. Keeping in mind that the vehicle has 4 wheels, and the motorcycle has 2 wheels, with its front wheel equipped with two disc brakes, it should be concluded that the disc brake is the most mass mechanism of a modern wheeled vehicle. Designing a disk brake with the required properties is impossible without considering the conditions of its operation. Since it is the main mechanism of the braking system and one of the systems that provides traffic safety, its correct functional calculation is of great social and national economic importance. In the existing methods for calculating disc brakes, it is believed that the specific pressure in the places of contact between the disc and the lining of the pads is constant. But the carried out study of operational wear of friction linings (disk brake lining pads, pads of the clutch single-disk and dual-disks) have theoretically proven that the assumption of a constant pressure on the area of friction lining is wrong. The formula obtained on this assumption (p = const) is unreasonably complex, though it is widely used in the literature and in the auto industry. It is proposed to perform a functional calculation of the disk brake according to an extremely simple formula obtained from the kinematics of the shoe during braking, which assumes that p ≠ const and it is confirmed by operational wear and experiment.

The clutch is a linking element between the engine and transmission parts. The dynamics of engine loading and transmission and, accordingly, the loads which arise in their structural elements depend on the functioning of the clutch. Coupling with its diaphragm springs has become quite widespread on motor transport. There are various methods for calculating and simulating the operation of couplings with such springs. Nowadays, virtual stands based on the application of the software packages of dynamics of solid bodies with the introduction of flexible elements that allow to take into account the design features of vehicles and their aggregates using CAD and finite element models have become widespread. This method allows you to significantly reduce the number of full-scale tests, and, accordingly, the cost of the final product. Besides, the methods of dynamic solid modeling allow us to develop and verify the laws controlling the units and aggregates of vehicles. In order to make the virtual stand be similar to the actual model, it is necessary to create adequate models of parts, which will later be used in the dynamic solid model of such a stand. To verify the adequacy of finite element models at the design stage, it is advisable to make comparisons with analytical methods of calculation, since carrying out full-scale tests has rather a high labor input and cost. One of the most complex elements in the simulation of coupling is the diaphragm spring. One of the main specific indicators for comparison is its obtained elasticity characteristic, which significantly affects coupling. The paper compares two calculation methods of clutch spring - the analytical method and the method of finite element. The main difficulty in calculating the spring is its large displacement due to its thickness and the appearance of loss of stability during operation, which requires the use of special methods that allow to take into account the complex nature of the spring deformation. Comparative analysis showed that the results of the calculation for the above methods had a quantitative and qualitative convergence. Recommendations are given for solving problems of this kind.

The article analyzes the operating conditions of the damping device used on a mass-produced truck moving at different speeds along various road surfaces (smooth asphalt, flat cobblestone). The main feature of trucks shock absorbers operation is the work in the low speed zone up to 0.2 m/s of rod movement with periodic splashes of speeds up to 1 m/s and higher. The article states that this distinctive feature does not allow to fully use the shock absorber design with a recuperative effect of a linear electric machine. The expediency of using a rotating generator that allows to develop values of peak useful power up to 1200-1300 W is noted. In this case, there is the problem of converting the translatory motion of the rod into rotational motion of an electric machine rotor. The article stresses that the most suitable for this is the ball-screw transmission, which has the ability to work under dynamic load conditions inherent in the elements of the truck suspension. The application of the stringent mass-dimensional requirements to shock absorbers characteristics, namely, the compliance of their parameters with the currently used structures, does not allow to create a device that would repeat the damping characteristics of the existing hydraulic ones. This problem can be solved by changing the overall device dimensions and increasing its recuperative properties or by using a hybrid electro-hydraulic design. The article presents a sketch of a shock absorber with recuperative effect, which explains the principle of constructing a shock absorber with a synchronous generator possessing permanent magnets based on a ball-screw transmission to use it in trucks suspension systems.

The article considers one of the possible ways of constructing the robotic means of defect detection of ships hulls, dams, internal walls of nuclear reactors and similar objects. To solve such problems, the positioning provision of high-precision gauges relative to the surveyed surface is required. The achievement of necessary accuracy is a non-trivial task for both mobile ground robots and a remote-controlled unmanned underwater vehicle (RUUV), movement of which in water is carried out with the help of traditional type of propeller (screw-propeller). The preliminary justification shows that the propulsion system of the device must be hybrid and should include both screw- and contact propulsion units (wheel or track ones). To identify the peculiarities of the operation and the requirements for the information and measurement complex and to develop and test the controlling algorithms of the RUUV motion, it is necessary to create a mathematical model that takes into account all the capabilities of the hybrid propulsion complex and the operating conditions of the system. The article presents a mathematical model of a RUUV motion with propulsors of various types, taking into account all the main features of operating conditions and organization of work of hybrid propulsion systems. Based on it the research of system properties it is possible to conduct including the combined use of various types of motion means. It also gives the possibility to verify the applicability of both traditional and new algorithms of the RUUV motion control system when moving along the surveyed surface. The research gives an opportunity for the further study.