Truck Tractor Research Articles

Evaluation of the strength of the truck tractor’s frame under emergency braking conditions

Authors carried out a theoretical study of the force impact during emergency braking on the strength of the frame of a truck tractor as a part of a road train with a semi-trailer in order to build a model of the dependence of the safety factor index of the frame on the geometric and weight parameters of the car, semi-trailer, transported cargo and the type of the pavement. Using D'Alembert's principle, a generalized calculation scheme of the frame of the semi-trailer and the truck unit after reaching a steady deceleration during emergency braking while maintaining straight-line movement and adhesion of all wheels to pavement was made. Through a static calculation, the dependences for the unknown reactions of the car frame constraints were obtained, its dangerous cross-section was established, and the condition for the static strength of the longeron was determined. Using this condition and the obtained ratios for active and reactive loads, a model of the dependence of the safety margin coefficient of the car frame on the road train parameters was built. By the example of a road train consisting of a KrAZ-6446 truck tractor and a VARZ-6006 semi-trailer the application of the constructed model for evaluating the strength of the car frame and determining the permissible safe zone location of the center of gravity of different weights cargo in the plane of the road train is demonstrated. The method proposed in this work and the built model can be used to study the strength of the frames of truck tractors and semi-trailers of other manufacturers and types and to establish safe schemes for the placement and fastening of loads to ensure the operational reliability of the vehicle and the safety and security of cargo transportation.

Non-dominated sorting artificial rabbit multi-objective sizing optimization for a conceptual powertrain of a 6 × 4 battery electric tractor truck

In order to tackle the increasingly severe energy crisis, improving the efficiency of the powertrain system in battery electric vehicles has become an effective approach. Based on a 6 × 4 battery electric tractor truck (BETT), the paper focuses on enhancing the dynamic and economic performance of vehicles through advancements in configuration, control strategies, and parameter design. Firstly, a novel multi-motor torque coupling powertrain system based on the parallel-axle transmission is proposed and modeled. Then, an instantaneous minimum energy consumption control strategy for the economic performance simulation and an instantaneous maximum acceleration control strategy for the dynamic performance simulation are designed. Furthermore, a conventional heuristic single-objective optimization algorithm, artificial rabbit optimization (ARO), is improved into a multi-objectives version, non-dominated sorting artificial rabbit multi-objective optimization (NSARMO), by combining the fast non-dominated sorting (FNS) and modifying the calculation method of the energy factor. Finally, an optimization framework consisting of a control layer, model layer, and optimization layer is established and applied to the parameter optimization of the proposed powertrain system. Simulation results demonstrate that the optimization results of the proposed method are superior to those optimized by commonly used non-dominated sorting genetic algorithm-II (NSGA-II) and NSARMO without the modified energy factor, achieving a better balance between dynamic performance and economic performance. Moreover, the proposed method exhibits demonstrates 40.67% and 24.67% improvement in its ability to search for optimal Pareto solutions compared to NSARMO (-)(- means the calculation method of energy factor is not modified) and NSGA-II. At last, a hardware-in-the-loop (HIL) experiment bench is established, and the experiment results indicate that a scheme optimized by the proposed NSARMO exhibits only an approximate performance in energy consumption in the HIL environment compared to the simulation environment, which signifies the effectiveness of control strategy equipped with the optimization results optimized by the proposed method.

Analysis of the aerodynamic performance of truck semi-trailers

In the last time, trucks have shown a very high interest in terms of their technical and fuel consumption performance. Prioritizing the phenomenon of having trucks that transport as much, as quickly and as economically as possible, this represent a new challenge for industry and engineering, which are in continuous development. The attempt to create a bridge as stable as possible between technical and consumer performance is supported by the multitude of areas that, based on studies and experimental trials, allow optimization without interfering, substantially, with the actual transport of the goods (loading capacities and transport). The main objective of this paper is to present the possibility of improving the aerodynamic performance of trucks, focusing on semi-trailers. For this study, a truck modelled at one to one scale was used, whose aerodynamic performance was verified in the virtual environment (CFD–Computational Fluid Dynamics); this environment has the possibility to test several geometric models without requiring the layout of a vehicle in physical form. To check the performance, a basic model was created, a conventional truck (tractor unit with semi-trailer), to which various semi-trailer modifications were made, such as: total and partial coverage of the side areas, idea to create a more aerodynamic profile of the semi-trailer in the back and the addition of fairings under the platform (underbody of the semi-trailer). The results describe the impact these elements have and allow the visualization of the possible future profile that is as aerodynamic as possible for semi-trailers (therefore also for trucks) from both theoretical and technical point of view. Through the proposed improvements the capacity and the transport of the goods is not affected, in a significant way so it can be said that there is the possibility of implementation in the industry.

Multi-Criteria Analysis of Semi-Trucks with Conventional and Eco-Drives on the EU Market

The research provides a comparative theoretical investigation of the operational characteristics of an electric semi-truck and vehicles powered by conventional combustion engines using diesel fuel, hydrotreated vegetable oil (HVO), and methane (including biomethane) in the dual fuel configuration. The Volvo tractor units that are offered for retail in 2024, namely the Volvo FH Electric, Volvo FH500 in dual fuel configuration, and Volvo FH500TC Diesel Euro VI, were chosen for comparison. The considerations encompassed include the road tractor’s mass, energy usage, power-to-weight ratio, dynamics, ability to recharge or refuel, payload restrictions, impact on logistics expenses, compliance with regulations on drivers’ working hours, and a report on carbon dioxide emissions. The study concludes by discussing and drawing conclusions on the competitiveness of different drive types in truck tractors, specifically in relation to identifying the most suitable areas of application. Synthetic conclusions demonstrate the high effectiveness of the electric drive in urban and suburban conditions. However, vehicles equipped with internal combustion engines using renewable fuels fill the gap in energy-intensive drives in long-distance transport.

Planning rolling stock operation in international communications with modern requirements to cargo transportation technology

Introduction. The relevance of the research carried out is justified by the need to plan performance indicators of rolling stock in the context of changes in the technology of cargo transportation in international traffic when implementing the Draft Order of the Ministry of Transport of the Russian Federation. An obligatory element in the technology of cargo transportation is the re-coupling of a semi-trailer or reloading of cargo. In practice, there are additional costs for the transportation of goods due to the significant waiting time for interchange due to the deviation of the time of arrival of rolling stock transporting goods in international traffic to the interchange point in accordance with the contract from the planned time of arrival at the interchange point. Today, there is no methodology for planning the operation of rolling stock of road transport in international traffic that takes into account modern requirements for the technology of cargo transportation in terms of eliminating waiting time at the point of transfer or reloading of cargo. The purpose of this article is to develop an algorithm for a planning methodology based on the mathematical model of the functioning of rolling stock in international traffic, created for the first time by the authors, taking into account modern requirements for cargo transportation technology.Materials and methods. To achieve the purpose of the study, the scientific foundations of current planning of the work of a motor transport enterprise are applied. The development of a mathematical model for the functioning of rolling stock in international traffic was carried out on the basis of the criterion - minimum transportation costs, taking into account the duration of technological operations, including waiting time at the point of transfer or reloading of cargo. The systematic nature of the study lies in the fact that the properties of cargo transportation are manifested in relation to rolling stock and depend not only on the properties of the cargo, but also on transportation technology, the time of completion of the transport process, which are established in the contract and affect the performance of the rolling stock.Results. The use of planning methodology for the practice of functioning of rolling stock in international traffic, taking into account modern requirements for cargo transportation technology, was carried out using the example of transporting a disassembled hydraulic vulcanization press. Software and mathematics have been developed to calculate costs.Conclusions. A methodology for planning the functioning of rolling stock in international traffic has been developed, taking into account modern requirements for the technology of cargo transportation based on the created mathematical model, using regulatory requirements for the transportation of goods in international traffic and promising theoretical studies. Practical implementation is presented using the example of a DAF XF 480 FT truck tractor with a Kogel S24-1 semi-trailer.

Determination of the vehicle's carrying capacity taking into account the bearing capacity of the roads

Increasing the efficiency of using the technical parameters of trucks, in order to save resources, remains an urgent task in the operation of vehicles. Maximum vehicle performance is achieved when the vehicle's rated payload capacity is used to its full potential. As practice shows, due to the regulation of weight parameters, the actual carrying capacity, and, consequently, the performance of the vehicle is reduced. The increased load leads to the destruction of the road surface, therefore, for exceeding the standard values of the weight parameters of the car, carriers are subject to administrative punishment in the form of a fine. The actual task is to determine the actual load capacity of the vehicle when the limit value of the axle load according to the regulatory document is ensured. This paper proposes a method for determining the carrying capacity of road trains consisting of a truck tractor and a semi-trailer, taking into account the bearing capacity of highways. When determining the actual mass of the transported cargo, the maximum permissible values of the total mass and axle load of the vehicle were taken into account, which depend on the category of the road, as well as on the design features of the vehicle (type of suspension, wheels, center distance).

INTEGRATED RESEARCH OF MULTI-PURPOSE STANCHION BASKETS FOR TRANSPORTING TIMBER AND CONTAINERS

Analyses of cargo transport in 2021 show that despite the increased volume of cargo transported by all types of transport compared to 2020, road transport is still dominant compared to rail transport. Therefore, all actions aimed at improving these unfavorable relations (rail transport vs. road transport) in transport, particularly cargo transport, should be considered purposeful and justified. One such activity is the ongoing work on the design and construction of freight wagons for specialized transport. Unlike universal wagons, specialized wagons are characterized by a limited ability to transport a wide range of material groups. An example is the transport of timber. However, the development of new transport technologies, and above all, technical and organizational progress, force the organizers of these transport modes to look for new logistic and rolling stock solutions. The aforementioned transport of timber is an example of this. The transport of wood does not constitute a large volume of transport, but taking into account its transport issues (transport with large truck tractors, high axle loads, and high risks for other road users), it is a classic example of the fact that it should not be carried out by road over long distances. Therefore, all actions aimed at reducing these issues and improving efficiency by using rail transport are desirable and even necessary. The article presents an innovative design solution in the form of a stanchion basket installed on flat wagons, allowing the use of standard wagons of this type to transport both containers and timber as well as loads such as beams and pipes. Such a solution will allow the use of empty runs of these wagons after unloading wood at the destination station for further transport of containers and vice versa. The considerations described in the article show the research process at the construction stage and testing the prototype of the built basket and the wagon with the stanchion basket structure placed on it.

Estimation of efficiency of technical solutions of an active road train by means of physical modelling

Introduction (problem statement and relevance). The article describes a physical model of a road train with active drive of semi-trailer wheels. The results of research tests of the physical model are given, with the help of which the adequacy of the mathematical models of dynamics of the road train as a part of a truck tractor and semi-trailer with active wheel drive is evaluated. The purpose of the study is estimation of efficiency of the technical solutions aimed at increase of vehicle passability and maneuverability.Methodology and research methods. In the course of the study the method of analysis of results of tests of the operating active road train scaled mock-up, the method of comparative analysis of the results of mathematical and physical modelling have been used. Scientific novelty and results. The performed studies confirmed correlation of the physical and mathematical modelling results, as well as indicated that the use of physical modelling serves as an efficient method to obtain an objective assessment of operational properties of the designed road train. The article considers constraints and limitations of using a scalable vehicle to study its dynamics. Matters of model parameters validity, conditions for dynamic similarity, and physical modelling results for active road train dynamics are given.Practical significance. Physical modelling of a (full-)scale sample using a scaled model reduces the costs and time when developing an active road train with new technical solutions, and increases reliability of the results obtained through the mathematical and physical modelling.

ANALYSIS OF PARAMETERS AFFECTING FUEL CONSUMPTION BASED ON STATISTICAL MODELLING

Fluctuating fuel prices and the importance of road transport in the contextof the environmental impact of transport make the research relatedto fuel consumption analyses still up‑to‑date and socially important. Thearticle presents the methodology for determining the statistical modelof fuel consumption based on the analysis of the significance of drivingparameters. The fleet of trucks (sets of tractor truck and semi‑trailer) wasselected as the research object due to their dominant share in the roadcommercial transport sector in the transport of goods. In order to calculatedeterminants of fuel consumption, the classic method of least squares wasused, as a result of which an optimal statistical model of fuel consumptionwas developed using the elimination method. The model developed wasalso verified based on the real data.

Improving the stability and handling of tractors when towing trailers and coupled units

BACKGROUND: Currently, almost all agricultural work is performed using tractors. As the transport speed of a tractor train increases, the amplitude of lateral and horizontal oscillations of its coupled units emerges and increases. At certain velocities, these oscillations become so large that they can lead to a rollover, in addition, shock loads occur in coupling devices, which make it difficult to handle a tractor train. The traditional method to prevent this is the velocity limit, which does not guarantee a positive result.
 AIMS: Development of methods to improve stability, handling and safety of wheeled tractor trains by reducing the galloping and yawing of a truck tractor when towing heavy loads.
 METHODS: The following options of the design of the system for countering the occurrence of self-oscillations in the design of a wheeled tractor train ensuring a reduction in the level of self-oscillations, increasing the stability, handling and safety of the tractor train have been proposed: the coupling device equipped with hydraulic damping devices operating at longitudinal and lateral folding; the control system for the individual traction electric drive of a truck tractor preventing the loss of wheel grip with the ground surface; the combined use of the control system for the individual traction electric drive of a truck tractor and the coupling device equipped with hydraulic damping devices; the combined use of the coupling device equipped with hydraulic damping devices and a steering correction system.
 RESULTS: With use of simulation modeling methods, it has been established that the coupling device equipped with hydraulic damping devices adjustable by the folding angle of the tractor train and by the yaw angle oscillations of a truck tractor body should be recognized as the most acceptable and effective system for reducing self-oscillations of a wheeled tractor train at the current state of the art.
 CONCLUSIONS: The practical value of the study lies in the possibility of using the proposed methods to eliminate the risk of self-oscillating processes in the design of promising types of agricultural machinery.

An unneglected source to ambient brown carbon and VOCs at harbor area: LNG tractor truck

The ambient air quality of harbors area in Asia is commonly more polluted compared to other continents. The airborne pollutant is directly or indirectly related to a significant impact of traffic emissions. This study for the first time assessed the impacts on brown carbon (BrC) and volatile organic compounds (VOCs) from in-port liquid natural gas (LNG) tractor truck at harbor areas, via conducting real-time monitoring of VOCs characteristic and sampling for ambient air at a harbor (named as W harbor) in Shanghai, China, collecting emissions of in-port LNG tractor truck and miniCast in laboratory, as well as statistics of external container diesel trucks in the port for further validation. HPLC/DAD/Q-Tof MS was adopted for sample analysis. Results showed that many CHO compounds were associated with vehicle exhausts. Among of them, aliphatic CHO compounds with low degree of unsaturation were identified as fatty acids and fatty acid methyl esters extensively existing in fuel combustion emissions. And non-aliphatic CHO compounds characterized by low O/C ratios (<0.17) identified for the harbor air came from the emissions of in-port LNG power trucks with low-speed driving and idling. The ambient average non-methane total hydrocarbons (NMHC) concentration (0.59 ppm) at W harbor was much greater than that for other areas in Shanghai. The higher ratios of toluene/benzene (3.30) and m/p-xylene/ethylbenzene (3.11) observed at W harbor implied instead of external container diesel trucks, the dominating contributing of internal LNG tractor trucks to ambient VOCs cannot be neglected. This study concluded that LNG is not as clean as it was expected. The LNG-fueled vehicles can produce strong light-absorption chromophores as well as high concentration of VOCs.

Оптимизация конструктивных параметров пневмогидравлического седельно-сцепного устройства лесовозного автопоезда

In this study, the benefits of logging transportation under modern conditions by semitrailer hauling rig are examined, which consists of a truck tractor connected to a semitrailer. Furthermore, an analysis is made of the operational implications of using log road trains in insufficiently arranged road conditions. The article describes the potential scientific directions that can optimize the efficiency of semitrailer trucks. An improved construction of a regenerative fifth-wheel coupling device is proposed. It provides better reliability, reduces fuel consumption for log trucks, and gives better working conditions for drivers, along with reduced dynamic loads between the links of the units that occur during the movement in unsteady modes. The research methodology includes the application of the mathematical framework of multifactorial optimization. The specified analytical formulas are derived to determine the performance efficiency of the regenerative fifth-wheel coupling. It is revealed the connections between the hydraulic cylinder piston stroke values of the regenerative fifth-wheel coupling device, the weight of the loaded semitrailer, the vehicle acceleration during speeding up and braking, and the modifications of the performance indicators of the latching mechanism. The optimal value of the stroke of the pistons of the hydraulic cylinder is determined, which is 200 mm. It provides a power recovery of 6.5 kW and better longitudinal acceleration of the semitrailer at 0.72 m/s2. Moreover, it is found that the change in acceleration during the increase in velocity and braking from 1 to 3 m/s2 gives the change in recuperated power from 2.2 to 6.8 m/s2. At the same time, the average longitudinal acceleration of the semitrailer varies from 0.27 to 0.75 m/s2. Changing the load of the semitrailer from 5 to 25 tons allows increasing the recuperated power from 1.6 to 7.9 kW and reducing the longitudinal acceleration of the semitrailer from 2.8 to 0.53 m/s2. The influence graphs and optimization cartograms present the diameter and hydraulic cylinder piston stroke values of the regenerative fifth-wheel coupling device on the regenerated power and longitudinal acceleration of the semitrailer. According to the optimization cartograms, the average regenerative power is determined using a graph-analytical method. It is equal to 6.5 kW with the diameter of a regenerative hydraulic cylinder of 110 mm and a hydraulic cylinder piston stroke of 200 mm. For citation: Posmetyev V.I., Nikonov V.O., Manukovskii A.Yu., Posmetyev V.V., Avdyuhin A.V. Optimization of Structural Parameters by Improvement of Pneumohydraulic FifthWheel Coupling Device at Semitrailer Hauling Rig. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 3, pp. 126–139. (In Russ.). https://doi.org/10.37482/0536-1036-2023-3-126-139

Method for detecting the loss of stability of the movement of tractors when towing a trailer or a coupled unit

BACKGROUND:Currently, combines and tractors, being the most energy-intensive transport and technological machines for agricultural purposes, largely determine the possibility of transition to an efficient and environmentally friendly agricultural economy, and also provide the technical aspect of the transformation of the agro-industrial complex into the leading sector of the countrys industry. One of the sources of dynamic loads in the units and subsystems of tractor equipment are self-oscillating modes.&#x0D; AIMS:Study of the conditions for the occurrence of self-oscillating processes in the design of wheeled tractor trains and development of methods to increase the handling and safety of their movement by means of reducing the galloping and yawing of the tractor-tractor when towing heavy loads.&#x0D; METHODS:It has been established that due to the coupling of oscillations along the longitudinal displacement of a truck tractor and a trailer with oscillations along the vertical displacement of the center of mass and with pitch angle oscillations of the truck tractor, when an auto-oscillatory mode occurs in the interaction zone of an elastic wheel with a solid surface, the same mode of self-oscillation will occur along the mentioned degrees of freedom. Moreover, it is possible to specify the sequence of occurrence of self-oscillating modes in different zones of the tractor train design.&#x0D; RESULTS:First, self-oscillations are excited in the contact patch of a wheel with a solid surface when a complete slip occurs, then self-oscillations along the pitch angle of a truck tractor body begin and after that self-oscillations along the vertical displacement of the center of mass of a truck tractor occur. Folding angle oscillations of a tractor train are associated with oscillations of the translational motion of wheel centers, which lead to the emergence of an self-oscillating mode, both with partial and full slip in the interaction zone of an elastic tire with a solid surface. Since the self-oscillations of each of the wheels occur at random times, the self-oscillations of a truck tractor along the folding angle will be chaotic.&#x0D; CONCLUSIONS:The practical value of the study lies in the possibility of using the proposed methods to identify the danger of self-oscillating processes in the design of promising types of agricultural machinery.

ASSESSMENT OF THE FUEL CONSUMPTION OF CARS BY SPECIFIC VALUES OF FUEL CONSUMPTION AND EFFECTIVE POWER

The need to control fuel consumption during vehicle operation is considered. The analysis of analytical methods for assessing the fuel efficiency of vehicles is presented. The current in Ukraine norms of rationing of fuel consumption are analyzed. The main disadvantages of accounting for fuels and lubricants in our country and in other countries are indicated. A statistical assessment of fuel consumption indicators was carried out according to the methodology of the Ministry of Infrastructure of Ukraine. The graphical dependences of the distribution of fuel consumption for the main groups of cars, sawn out according to the data of regulatory and legal information, are obtained. A regression assessment of the relationship between fuel consumption and the main technical parameters of a vehicle has been performed. The parameters for a mathematical model for calculating fuel consumption for the main groups of vehicles in the agricultural sector are obtained - these are dump trucks and truck tractors. The adequacy of the model, the quality of the parameters, and the confidence interval of the domain of determination are assessed. It is proposed to combine several methods for standardizing fuel consumption, which will allow setting the standard value by a calculation method. An assessment was made of the consistency of the obtained regression model with the data that were obtained using the methodology that is used in KhNADU to calculate the base rate of fuel consumption. Comparison of fuel consumption rates obtained by different methods is given. An algorithm for the use of a regression model for the method of accounting for the consumption of fuels and lubricants at road transport enterprises has been developed. Conclusions are formulated and the ways of further research aimed at improving the methodology for standardizing fuel consumption in our country are indicated.

MAKNA REPRESENTAMEN KENDARAAN PADA FILM ANIMASI ANAK CAR TOONS COMPILATION: KAJIAN SEMIOTIKA C.S. PEIRCE

Car Toons Compilation is an animated film by the YouTube channel First Toons which contains a compilation of episodes of Car Toons, including A Tow Truck, A Water Truck, and A Tractor. Car Toons tells a different story in each episode but still includes car elements. This study aims to discuss the semiotic understanding of the animated film by using Peirce's semiotic theory, especially icons, indexes, and symbols. The method used in this study is a qualitative method with descriptive analysis, which emphasizes the process of semiosis with the meaning of the relationship between signs or representamen in the elements of animated films and their benefits for children. The study results show that the animated films A Tow Truck, A Water Truck, and A Tractor have imaginary icons, namely visuals based on similarities to reality. The Tow Truck's indexicality as a saviour for a breaking car has a symbol of a towing tool that has a tip like a fishing hook on the back of the truck. The indexicality of the Water Truck is used to save alive whales even though they are on land. The blue object is a symbol of water. Tractor truck indexicality that agricultural land can be planted due to tractor services, its symbolism is that the animation of land with plants is agricultural land. Based on this discussion, the meaning of representamen provides benefits for children in the form of understanding the types of trucks and their uses.

Air Pollution Emission Balance as A Tool for Optimizing Intermodal Transport of Goods

The aim of the work was to check how the combination of different types of engines in truck tractors and locomotives will affect pollutant emissions per one loading unit in intermodal transport on the route from Nowy Sącz to Kołobrzeg. The scope of the work includes a review of the literature on the impact of transport on the environment and the importance of intermodal transport in the structure of domestic freight transport. Calculations of air pollution emissions were made when using four variants of intermodal transport. The obtained results were compared with the applicable air pollution emission standards in the European Union and proposals for the optimal use of intermodal transport with regard to the environmental criterion were indicated.

Analysis of Truck Tractor Tire Damage in the Context of the Study of Road Accident Causes

There are many accidents in road traffic involving both heavy goods vehicles and passenger vehicles, and the interpretation of the causes of some accidents can be very difficult. The paper presents the results of an analysis of the road accident causes involving a truck and two passenger cars. The hypothesis was verified that the incident took place after the damage to the front wheel of the truck, which resulted in an uncontrolled change of the direction of its travel and leaving the lane in the opposite direction of the passenger cars. The damaged tire was inspected, and traces were described in the form of cracks on the side surface, irregular abrasion on the central part of the side surface and near the bead, as well as deformations resulting from damage to the cord. The thesis was made that the tire cracked as a result of its material structure defects. In order to verify it, bench tests were carried out on the deformation of the tire sidewall at various load conditions, which simulated driving with too little air pressure in the tire. Detailed studies of the fracture of the tire sidewall and the wires that make up its steel cord were carried out. Macroscopic examination of the cord wires on eight samples revealed the presence of corrosion changes that should not occur under normal operating conditions. The results of the research work indicate that tire rupture was caused by delamination of the material coatings and corrosion of the steel cord wires. These defects could have arisen due to the earlier cracking of the rubber layer and the ingress of moisture or as a result of the use of corroded steel cord wires in tire production. In the analyzed case, the driver could not regain control of the vehicle and avoid a collision with oncoming vehicles.

ОЦЕНКА ЭФФЕКТИВНОСТИ ИСПОЛЬЗОВАНИЯ СУЩЕСТВУЮЩИХ СХЕМ КОМПОНОВАНИЯ ЛЕСОВОЗНЫХ АВТОПОЕЗДОВ

This article discusses the relevance of using timber trucks for the removal of timber. The existing schemes for the layout of timber road trains are given. The analysis of the main ad-vantages of logging trucks with trailers, logging truck tractors with semi-trailers, logging trucks with drop trailers, as well as three-link logging road trains is carried out. The dependences of changes in the load capacities of saddle and trailer road trains on their specific load capacity are presented. The regularities of changes in the specific volume of the platform from the carrying capacities of trailer and saddle road trains are given. The dependences of the mounting length of the frame and the specific area of the platform of saddle and trailer road trains on their carrying capacity are analyzed. A comparison of the efficiency indicators of a trailer logging road train and a logging road train with dissolution is given. The patterns of changes in harmful emissions into the environment during a given period of time by heavy-duty multilink timber haulers are shown. The technical and economic efficiency of hauling timber of the same batch by different configurations of timber road trains is con-sidered. The regularities of the performance of three-link and two-link road trains from the permissible speed of their movement, as well as the regularities of changes in their fuel characteristics when driving on roads of a var-iable longitudinal profile, are analyzed.

Development of an Independent Front Suspension for Truck Tractors

Design and experimental validation stages of an independent front suspension (IFS) that is designed for truck tractors of articulated commercial vehicles are summarised. Firstly, the suspension geometry, which satisfies the required conditions of minimum deviation of camber angle and track width during wheel travel, is obtained within the given design volume by using Multibody Systems (MBS) and Design of Experiments (DOE) approaches. Subsequently, the kinetic analysis is carried out for the suspension system and the critical design loads that may act on the structural elements are determined. Taking these loads into account, the mechanical design of the suspension system elements is performed. The Finite Element Analysis (FEA) is applied to the complete suspension system for the chosen critical load conditions. Stress concentrated regions on the crucial system elements are determined and improvements are indicated, which result in the reduction of stress concentrations. In the last part of the study, prototyping and fatigue tests are carried out. Throughout bench tests, in which real service conditions are simulated, no failure of any sort is encountered. The final suspension system (pair) is 31% lighter than an equivalent rigid front axle in terms of load capacity.

Analysis of the market structure of long-distance transport vehicles in the context of retrofitting diesel engines with modern dual-fuel systems.

The demands placed on vehicles are constantly increasing. European legislation has forced commercial vehicle manufacturers to develop ever more powerful and dynamic engines with low fuel consumption. With the appearance of exhaust gas standards, truck manufacturers realized that it was necessary to improve the fuel supply system so that the combustion process was more efficient. To achieve this the fuel injected into the cylinders had to be finer in order to mix more easily with air. High-pressure unit injection systems have proved to be a good and reliable solution. They are also relatively cheap to produce and less prone to fuel contamination. Many years and millions of failure-free kilometers traveled on unit injectors effectively distracted some users and producers from the Common Rail system. Exhaust gas standards and increasing consumer expectations forced manufacturers to take another step in their development, i.e. the need for more precise fuel injection control. The injectors had to run faster in order to carry out the initiation dose, the actual injection and the extra injection. All these modifications make diesel engines in commercial vehicles such as tractor units much more powerful. They also allow for cooperation with aftermarket dual-fuel CNG-ON and LPG-ON installations. Dual-fuel solutions are perhaps another step towards reducing emissions, and thanks to reduced tolls, they are becoming a real alternative to conventional fuel-powered tractor units. This work focuses on the structure of the truck tractor market in terms of selecting cars used for the use of a non-factory dual-fuel CNG-ON installation.