Vol 88, No 6 (2021)

The article describes the history of the development and creation of the first domestic neutralizers of exhaust gases of internal combustion engines, which began with testing and research of foreign neutralizers. Sequential stages of design, study and testing of domestic converters for gasoline and diesel engines are considered. There are described the following processes: the process of developing methods for testing engines for toxicity and the process of creating estimated indicators and developing normative and technical documents in the field of toxicity of engines and vehicles.

The work is devoted to the development of a method for predicting the technical progress of self-propelled grain and forage harvesters and the substantiation of systems for their implementation. The necessity of improving the existing and developing new methods for predicting the properties of machinery, taking into account the existing features of the agro-industrial enterprises operation, were substantiated. A new technique for the synthesis of the technical appearance of products is proposed with the possibility of identifying the nomenclature of defining parameters based on the actual change in their values, ranking indicators with highlighting the most important of them for each category of business entities, forecasting using fuzzy logic methods, as well as justification of required machine systems of new generations using object-oriented design methods. A description of each of the stages of the forecasting process is given. On the basis of mass-produced grain and forage harvesters in Russia, an analysis of their constructive evolution with the allocation of stable and inherited development criteria has been carried out. A comparative analysis of the actual change in the defining parameters for machinery of the current and previous generations is shown. The technique and the results of forecasting the selected defining parameters are presented. It is shown that the predicted level of properties forms multidirectional requirements, which, from the point of view of implementation on the basis of existing design approaches, are contradictory. Taking into account the existing problems of motion dynamics and vibration loading of the workplace of operators of machinery of the current generation, it is stated that those multidirectional requirements are unattainable. Using the methods of object-oriented analysis, an object-target diagram of classes of possible options for constructing a vibration protection system for machinery of a new generation has been compiled. The relations of inheritance, which established the hierarchical decomposition of goals, were determined. It is shown that it is more expedient to control the selected vibration processes of combines without significant changes in their design and layout by means of systems for dynamic stabilization of the body and vibration isolation of the operator's workplace.

An increase in the slipping of a wheel propeller leads both to the energy loss and, up to a certain limit, the traction force increase. In this regard, in order to reduce energy losses for the movement of the vehicle, it is necessary to limit wheel slip at a level sufficient to create the required traction. Most of the existing algorithms aimed at implementing this constraint require information about the vehicle's linear speed. However, measuring the latter with a given accuracy outside laboratory conditions is difficult, which in some cases leads to a malfunction of the control algorithm. Therefore, it is relevant to develop a control method for the traction control system; in particular, for the case of acceleration, which will make it possible to estimate and limit wheel slip within specified limits with unknown characteristics of the supporting surface and the vehicle speed.

The article is devoted to the development of a method for assessing and limiting slipping of a wheeled engine at a level sufficient to realize the required tractive forces without using data on the vehicle's linear speed and adhesion properties of the supporting surface.

The article describes the mathematical model of the dynamics of the rectilinear movement of the “quarter” of the vehicle on a solid flat horizontal support surface. Through virtual experiments simulating the acceleration of a “quarter” of the vehicle with low slip, there was established a relationship between the traction force on the wheel axle and the kinematic parameters of the rotational motion, which are measurable and can be controlled during the movement of the vehicle, for example, using dynamometric wheels. On the basis of the obtained criterion, a regulator was developed to limit wheel slip during vehicle acceleration. The effectiveness of the developed regulator is proved by mathematical modeling of the acceleration of a “quarter” of the vehicle with different intensities on two types of supporting surfaces. It is also substantiated analytically provided that the wheel slip is constant within the measurement interval.

The paper presents an approach to assessing and limiting the slip of the wheels of a vehicle during acceleration using a regulator based on fuzzy logic. A theoretical justification of the proposed method is given. It does not require information about the linear speed of the vehicle and the adhesion properties of a wheel with a supporting surface.

An algorithm for the operation of the traction control system was developed. It allows to limit wheel slip at a given level while maintaining a sufficient margin of traction, which leads to a decrease in tire wear, a decrease in the likelihood of loss of mobility and an increase in the energy efficiency of the vehicle.

To increase the cross-country ability of ground trackless vehicles for off-road container transportation by land, it is advisable to use track trains. When moving track trains, it is necessary to ensure high profile cross-country ability when overcoming obstacles in the vertical and horizontal planes. The property of maneuverability determines the ability of track trains to maintain mobility when maneuvering in the plan and depends on the adopted design and layout solutions and static agility. The article examines the maneuverability of track trains for two variants of design and layout solutions: a track single-articulated semi-trailer train and a double-articulated track train. The movement of each of the track trains is compared according to the criterion of energy efficiency, taking into account two methods of turning: kinematic and power turning methods.

A variant of the design and layout of a track train was determined. It has better static agility and a smaller overall turning radius.

To assess energy efficiency, the method of simulation mathematical modeling is used, taking into account the peculiarities of the interaction of the driving machine with the support base. The article provides a description of the regulators that are used in the mathematical model and provide the turn of caterpillar trains with a minimum radius. To compare the energy efficiency of performing maneuvers, several design schemes are considered: with one active link or with two active links.

A turning method was determined. It is advisable to use it to ensure high turnability of track trains. The effect of the length of the bearing surfaces of caterpillars active links on energy efficiency is determined as well. In addition, the results of a comparison of track trains according to the criterion of energy efficiency are given.

Nowadays an urgent direction in agriculture is the issue of increasing the volume of production. In order to do this, it is necessary to have powerful energy facilities operating at high speed modes. But at the same time, the increased vibrations appear in the tractor transmission, which are transmitted from the soil. These fluctuations negatively affect the units and assemblies of the mobile power plant, lead to an increase in the consumption of fuel and lubricants, a deterioration in the ride smoothness, and also have a negative effect on the health of the vehicle operator. For this reason, it is necessary to improve the design of modern mobile power tools.

Analysis of works on this topic has shown that the most effective way to protect against dynamic loads from external influences is the setting of elastic elements in the final link of the transmission. The paper analyzes various designs of elastic damping drives (EDD). The design of the EDD of driving wheels was proposed (utility model patent of the Russian Federation No. 203460). The proposed blade EDD is rigidly fixed on the wheel disk and has two cavities. The forward stroke cavity is connected to two gas-hydraulic accumulators, one of which has an adjustable throttle, and the second cavity of the return stroke is connected to one gas-hydraulic accumulator. Both cavities of the damper are filled with a magneto-rheological fluid, which viscosity changes by electromagnetic coils, depending on changes in the oscillations of the moment on the semi-axes. The drives were installed on the MTZ-80.1 tractor. The studies were carried out as part of transport and arable units. When working with a transport unit on a dirt road due to the EDD the slipping of the propellers is reduced and the speed of movement is increased by 6–9 %. When the tractor is plowing, the skidding of the propellers is reduced by 10–16 %, and the speed of movement is increased by 7–12 %. This increases the productivity of the tractor unit by 6–12 %.

The article analyzes suburban bus transportation on specific routes in the Republic of Sakha (Yakutia). Route No. 101 Yakutsk – Tabaga with a total length of 31 km was chosen for the experimental study. The timetable for the movement of buses of the municipal unitary enterprise Yakutsk Passenger Transport Enterprise (YAPAK) on the suburban route is given. The main technical data of the LiAZ-5256.57 bus were studied. In accordance with international rules for buses, the determination of the amount of fuel consumption and specific emissions of normalized toxic components is carried out using a driving cycle on working drums. A technique to calculate fuel consumption is used for modeling engine performance indicators that provide a change in the traction and speed characteristics of the vehicle in accordance with the established driving cycle. The calculated fuel consumption results for the NEDC driving cycle are compared with experimental data. As a comparison of calculated and theoretical data on fuel consumption with practical data, a Cummins type CG 250 engine is considered. The internal combustion engine is installed on the LiAZ-5256.57 bus. Experimental data on the fuel consumption of this bus per 100 kilometers (km) showed 49 nm³, and theoretical calculations of the fuel consumption of the bus per 100 km using the proposed method showed 48 nm³.

Thus, to assess the traction and speed characteristics of the bus, the proposed combined method can be used, which makes it possible to obtain a calculation of fuel consumption that is closer to the experimental data on the driving cycle. Based on the initial data of the vehicle, the effective performance of the engine is evaluated. A computational method for modeling tests and an experimental driving cycle for motor vehicles with a total mass of more than five tons are proposed.