Vol 16, No 4 (2022)

On December 23, 2022, the Ministry of Science and Higher Education of the Russian Federation presented awards to the laureates of the Prizes of the Government of the Russian Federation in the field of science and technology for 2022. The Prize of the Government of the Russian Federation was awarded to the work of the team of authors «Development of highly efficient wheeled transport and technological means for the accelerated socio-economic development of the territories of the Far North of the Russian Federation.» The honorary title of the Prize Laureate was given to a number of scientists from leading scientific institutions, including members of the editorial board, as well as regular contributors to the Izvestiya MGTU «MAMI» journal.

BACKGROUND: The worldwide powertrain engineering tendency is reduction of mass and dimension properties of an engine with simultaneous increase of its specific power and power-to-weight ratio. It can be achieved with compression ratio increase, engine cycle improvement, implementation of supercharging system and direct fuel injection. With the direct injection systems implementation, the issue of fuel accumulation in oil became relevant.

AIMS: The article addresses general issues related to fuel accumulation in the motor oil.

METHODS: Analysis of the published data addressing this issue.

RESULTS: The reasons of fuel entry into oil were formulated, the possible acceptable limits of fuel concentration in oil were defined, and the data of vehicle fleet observation performed by specialists during several years was given.

CONCLUSIONS: There is rather considerable range of opinions and recommendations regarding acceptable fuel concentration in oil. Therefore, it may be concluded that the value of fuel concentration in itself makes little difference, and, in order to define the maximal acceptable level of fuel concentration in oil, it is reasonable to carry out studies of determination acceptable limits of particular motor oil properties, primarily viscosity.

BACKGROUND: Thermo power industry demands the high level of reliability of pump equipment. Regarding that, improvement of reliability of feed pump structure and balancing device in particular is a relevant issue.

AIMS: To perform numerical simulation of a balancing device in order to determine its optimal design and parameters. The study object is the balancing device of the PEN 290-115 feed pump

METHODS: Two types of the balancing piston, two-stage and single-stage, were studied. The series of computational fluid dynamics simulations of the three-dimensional flow of a viscous liquid were performed using the ANSYS CFX software in order to study the efficiency of given designs.

RESULTS: The calculated characteristics of the two designs of the unloading device were obtained. The influence of roughness and radial clearance on the efficiency of a cylindrical piston was studied. The simulation results showed that the radial clearance decrease leads to balancing device losses decrease. The roughness value increase may also lead to the leaks decrease, but its excessive increase leads to friction losses increase, so it is necessary to control both parameters when searching for the optimal roughness value.

CONCLUSIONS: The optimal design of the balancing piston, which combines simplicity of manufacturing, reliability and energy efficiency, is proposed.

BACKGROUND: Vehicle passengers may be exposed to high concentrations of hazardous substances, especially in heavy traffic and traffic jams. The air exchange rate is an important factor in assessment of the level of pollutant substances exposure on the people inside the vehicle.

AIMS: Development of the air exchange rate measuring method, based on carbon dioxide concentration build-up in the vehicle cabin air.

MATERIALS AND METHODS: The presented method makes possible to determine the air exchange rate in a stationary vehicle or vehicle, moving with constant velocity. The set of experiments was carried out, in which the air exchange rate was determined in a stationary vehicle and in a moving vehicle at velocities of 30, 60 and 90 km/h. For each velocity, the air exchange rate was determined for three air conditioning system modes, such as intake air supply, recirculation mode and air conditioning system off.

RESULTS: According to the results of measurements, the air exchange rate varied from 0.42 h^-1 to 76.17 h^-1.

CONCLUSIONS: The study results corresponds to the results, obtained earlier by other authors, using alternative methods, and may be used for development of regulatory requirements to control the pollutant substances exposure on the people inside vehicle cabins and for the people healthcare strategy formation.

BACKGROUND: At present time, branches of industry have been increasingly filled with electronics, capable of controlling different processes in order to achieve demanded paremeters values. Automotive industry, safety issues of which such as vehicle stability and handling are paid much attention, have not become an exclusion. Vehicle safety improvement is one of the areas of development of modern auto-motive industry. Manufacturers permanentally increase the number of control systems and raise the level of control on wheeled vehicle motion parameters in order to achieve the highest possible level of stability and handling. Using of various all-wheel-drive systems becomes more relevant and reasonable. Traction force distribution between all wheels improves dynamic performance indicators, makes cross-country ability better in similar road conditions and allows using algorithms, improving handling and course-keeping ability of a vehicle.

AIMS: Determination of variation range of the control parameter in order to ensure stable straight-line motion of a vehicle with controlled transmission.

MATERIALS AND METHODS: The two-axled vehicle, which transmission has an ability of torque distribution between front and rear axles, is considered in the article. The system of diiferential equations in terms of “middle” wheels side slip angles was made up in the study. The Liénard–Chipart algebraic cri-terion was used to define variation ranges of the control parameter in order to ensure stable straight-line motion of the vehicle.

RESULTS: The obtained variation ranges of the control parameter are included in the adjustment range of modern torque distribution mechanisms, consequently, it is possible to speak about ability to ensure stability of straight-line motion of a full-wheel-driven vehicle with currently existing mechanisms. The scientific novelty of the study lies in analytical determination of variation range of the control parameter for the case of straight-line motion of a vehicle equipped with the electronic stability control.

CONCLUSIONS: Practical value of the study lies in establishment of ability to ensure stability of straight-line motion of a full-wheel-driven vehicle with currently existing mechanisms.

BACKGROUND: The issue of coordinated control of vehicles’ windscreen wipers, not linked to each other with mechanical joints, is related to aiming to make the equipment more compact. Modern microprocessor controlling are helpful to solve this issue with use of electric drive as well as problems of logical control and interaction with high-level controlling equipment.

AIMS: The comprehensive solution of the issue of coordinated control of movement of panoramic windscreen wipers without mechanical links as well as the solution of secondary problems of control with use of tools of electric drive considering various factors.

METHODS: The algorithm of windscreen wipers movement coordination in nontracking system of automatic stabilization of electric motors rotation velocities with positioning in trajectories’ control points. Among the factors, necessary to consider in development, there are design of mechanism of windscreen wipers, the characteristic of mechanical load on them, type and location of sensors, required dynamics and accuracy of coordinates adjustment, behavior of electromagnetic processes in power converter and restriction of computing capabilities of a microcontroller.

RESULTS: The electric drive ensures visually balanced coordinated movement of windscreen wipers, which is resistant to load change caused by the condition of the windscreen as well as torques of gravity force acting on the windscreen wipers. The logical control based on discrete switches ensures selection of the movement mode, whereas the connection through digital circuits ensures data exchange with the controlling equipment. Technical solutions ensuring simple tuning of the electric drive are implemented.

CONCLUSIONS: The given solution of issues of coordination of windscreen wipers movement, automatic adjustment of coordinates considering dynamics of movement control, logical control and coupling with the high-level controlling equipment has practical value for development of various control systems.

On November 2, 2022, the Honored Mechanical Engineer of the Russian Federation, Doctor of Technical Sciences, Professor Konstantin I. Gorodetsky, the author of a number of works on transmissions of tractors and agricultural machines, died. Konstantin was born on January 11, 1932. He graduated from the tractor department of the Moscow Automotive Institute (MAMI). An important achievement of K. Gorodetsky in the scientific plan is his proposed refinement of the formulas of V. Mishke, which make it possible to evaluate the change in the efficiency of rotary hydraulic machines with a change in their operating mode. The resulting formulas are called “Gorodetsky’s formulas”.