Vol 92, No 2 (2025)

BACKGROUND: The use of ammonia (NH3) as a diesel fuel additive is of great interest for addressing environmental and operational challenges, such as reducing harmful emissions and improving engine efficiency. However, the influence of ammonia on vibration parameters of diesel engines is still understudied, thus requiring detailed research.

AIM: This study aims to analyze the influence of ammonia (NH3) as a diesel fuel additive on vibration parameters of a diesel engine using an artificial neural network (ANN) designed to predict these parameters.

METHODS: The study employs modeling methods based on neural networks. TensorFlow and Keras frameworks were used to develop and train the neural network. Parameters of the engine (engine bore, speed, compression ratio, etc.) and fuel mixtures containing 5%, 10%, and 15% NH3 were used as inputs. The model's accuracy was assessed based on experimental data.

RESULTS: The developed ANN showed high vibration prediction accuracy (up to 98.67%). Experimental data showed that increased ammonia additive ratio in the fuel mixture results in increased engine vibration. The highest vibration amplitude was 11.67 m/s² at 15% NH3. The results indicate potential risks of lower engine performance when using ammonia, despite its environmental advantages.

CONCLUSION: The study showed that ammonia additives in diesel fuel increase engine vibration, which could affect its reliability and durability. Despite the high accuracy of neural network predictions, the observed increase in vibration requires further investigation. Additional research is required to ensure the safe use of NH3 as a fuel additive by focusing on optimal mixture proportions and the influence of other factors, such as pressure and temperature.

BACKGROUND: When springs are used, they undergo “compression-decompression” cyclic loading, resulting in a gradual decrease in elastic properties and performance, formation of microcracks, and the springs destruction. Moreover, if these are the springs of the valve mechanism of the internal combustion engine, then they are subject to heating, which intensifies the processes of loss of elasticity and destruction. In practice, spring control often comes down to its external inspection, assessment of geometric parameters and dynamic testing. The latter requires expensive equipment and a long period for the test itself.

AIM: Improvement of the non-destructive inspection method for determining the state of a coil spring using a new technical solution at the level of patentability.

METHODS: The presence of microcracks and their growth during cyclic loading leads to a change in the microshape of the cross-section of the spring coil, which affects the electrical properties, in particular, its electrical resistance. Therefore, assessing the performance of a spring comes down to determining the number and volume of microcracks. Measuring the microgeometry of the spring can be achieved using a highly sensitive microohmmeter with a division value of at least 10^-6 Ohms. In the working coils of the spring, especially on the “inner fiber of the coils” [1], the greatest tangential stresses arise during its operation. Consequently, the inner fiber of the working coils of the spring is more susceptible to the formation of microcracks.

RESULTS: To implement the proposed non-destructive inspection of the state of a helical coil spring, a device, including a microohmmeter and a mechanical type power structure for its tension and compression, is required. The tension and compression of the spring is monitored using a dynamometer. The terminals from the microohmmeter for measuring resistance are fixed on the spring coils under test. Determining the resistance value of a new spring and subsequent monitoring during operation will make it possible to identify a faulty element at an earlier stage and to determine the feasibility of restoring the spring.

CONCLUSION: The proposed technical solution simplifies monitoring the state of the entire spring without destroying it, reduces the time for monitoring its state as a whole, and reduces the energy intensity of this process.

BACKGROUND: The dynamics of agricultural production have gradually moved toward mechanization and maximizing efficiency. Understanding the relationship between mechanization and crop yield is crucial to improve productivity.

AIM: This study assesses the temporal pattern similarity between crop yield and the level of mechanization (LOM) and examines how LOM influences crop productivity over time.

MATERIALS AND METHODS: The study used ordinary least squares (OLS) regression with interaction terms for trend analysis and dynamic time warping (DTW) for pattern similarity. Descriptive statistics (standard deviation, mean, minimum, and maximum) and error metrics (MAE and RMSE) were used to assess the DTW distance performance between sequences.

RESULTS: The OLS analysis showed almost parallel trend lines (slopes 0.038% and 0.053%). The DTW analysis showed significant temporal alignment, with a 44.4% perfect match and a similarity score of 34 (34 optimal paths across 28 dataset pairs). Performance evaluation metrics—standard deviation, mean, minimum, and maximum—were 7.56 × 10⁻³, 1.08 × 10⁻², 1.42 × 10⁻⁵, and 3.22 × 10⁻², respectively. MAE and RMSE values were 6.33 × 10⁻³ and 7.56 × 10⁻³, respectively. Based on these values, average similarity, consistency, alignment quality, and error metrics were used to assess the level of similarity. These values indicate high similarity and consistency (based on the low mean DTW distances, standard deviation, and error metrics), despite occasional poor alignment.

CONCLUSION: The temporal similarity between LOM and crop yield showed that variations in LOM significantly impacted cereal crop yields. Agricultural productivity could benefit from mechanization through the use of contemporary technologies, improved supportive policies, and the integration of sustainable practices.

BACKGROUND: Regardless design advance of any vehicle or tractor, it cannot be ready for operation unless its power unit (mainly powerful diesel engine) is started by rotating the crankshaft with a rotation velocity no less than the minimal starting rotation velocity and overcoming rotation resistance. For this purpose, various starter systems, mostly electric starters, are used. Ensuring the working process of the electric starter system (ESS) of automotive and tractor engines, particular laws relate parameters and indicators of a battery, a starter circuit and a starter with each other. This paper covers the study of the main structural parameter: internal resistance of the ESS components, which affects on selection of nominal parameters of a battery and a starter.

AIM: Analysis of parameters and indicators of a battery and a starter in the conditions of low temperature engine start, having a significant influence of their internal resistance, ratio of which affects on weight, size and economic indicators of the main components of the electric starter system.

METHODS: This study is a part of the whole methodology of design of electric starter systems of automotive and tractor internal combustion engines, based on the synthesis of fundamental laws of electromagnetic induction; the second Kirchhoff’s law and the scaling theory using the system of relative values.

RESULTS: Considering the fact that expensive strategic materials, such as lead and copper, which resources are limited in the world, are used in manufacturing of batteries and starters, the right selection of their parameters during the design process allows minimizing weight, size and cost of the ESS components. For solving this problem, the graphical method of defining of resistance ratio between a battery and a starter in the ESS using the Gibbs triangle system, which is significantly easier and clearly evident for performing calculations, is proposed in the paper.

CONCLUSION: The problem of analytical definition of main parameters of the electric starter system of automotive and tractor engines in the worldwide experience of automotive and tractor engineering is still unsolved due to absence of mathematical apparatus of recalculation of the starter parameters at the working point to the nominal conditions. The algorithm of solving this problem in the part of definition of main structural parameters, which are resistance of a battery and a starter at their combined operation in this system, to minimize lead and copper consumption during their manufacturing is given in this paper.

BACKGROUND: To preserve the physical properties of soils, manufacturers of agricultural machinery use tools to reduce the pressure of the chassis supporting elements on the ground. One of them is reducing tire stiffness. The normal (radial) stiffness of a tire determines its ability to deform and the geometric parameters of the contact patch, which determine the pressure on the soil. The values of the normal tire stiffness during design modeling of the motion of tractors or agricultural machinery are calculated using existing universal experimental dependencies that are not specialized for tractors and agricultural machinery.

AIM: Development of a method for calculating the normal tire stiffness for tractors and agricultural machinery based on the loaded wheel radius.

METHODS: Calculations of the normal stiffness of the tires with a given free radius at normalized tire pressure and vertical load for tractors and agricultural machinery were carried out according to the new proposed method using the loaded radius. The used software products are Excel, MatLab, Curve Expert Professional.

RESULTS: A method has been developed for calculating the normal (radial) stiffness of an agricultural tire of a given free radius at a given load and internal pressure, based on the use of the loaded wheel radius. Using the obtained method, the stiffness of 93 tires for tractors and agricultural machinery was calculated. The maximum error in calculating the stiffness of agricultural tires using the proposed method was 20% for radial and diagonal tires and the average error was 6% for radial tires and 10% for bias tires.

CONCLUSION: A method for calculating the normal stiffness for agricultural tires using the loaded wheel radius has been developed and implemented. The method can be used in design modeling of the motion of a tractor or an agricultural machine.

BACKGROUND: Modern construction and agricultural machines have a hydraulic system that controls the working equipment. The reliability and long service life of the hydraulic system determines the reliability of the entire machine as a whole. Main of reasons for the failure of hydraulic systems are contamination of the working fluid with wear products of the internal surfaces of hydraulic machines, external contaminants, and changes in the properties of the working fluid. The filters currently used cannot always clean the working fluid during machine operation. The degree of cleaning of the working fluid depends not only on the fineness of filtration, but also on the features of the circulation of the working fluid circulation. Currently, insufficient attention is paid to the design of hydraulic systems, in particular to the mutual arrangement of individual elements of hydraulic systems.

AIM: Increasing the reliability of the hydraulic drive of construction and agricultural machines by assessing and preventing the possibility of forming incomplete circulation of the working fluid.

MATERIALS AND METHODS: The study object is a hydraulic system in which a hydraulic cylinder is installed. To evaluate the circulation of the working fluid in the hydraulic lines of the hydraulic system during the operation of the hydraulic cylinder operation, a hydraulic cylinder with a piston diameter of 100 mm, high-pressure hoses with an internal diameter of 8 mm and a length of 0.7 m to 8 m were used. A filter was provided in the hydraulic system for cleaning the working fluid, which was installed on the drain line. The assessment was made using the calculation method.

RESULTS: It was found that the quality of cleaning the working fluid of hydraulic systems when using hydraulic cylinders in them is affected by the ratio of the volumes in the piston and rod cavities to the volumes in the hydraulic lines that link these cavities with the distributor. It is proposed to use the distance coefficient to check the possibility of complete cleaning of the working fluid. Several technical solutions are proposed to eliminate the formation of zones in which complete circulation of the working fluid does not occur.

CONCLUSION: The reliability of hydraulic systems of construction and agricultural machines can be increased by improving the circulation of the working fluid. To do this, when designing hydraulic systems, it is necessary to take into account in advance the features of the circulation of the working fluid from hydraulic motors to distributors.

BACKGROUND: Natural vegetable oil has long been considered as an alternative type of bioadditives to diesel fuel. Currently, little research has been conducted on the reliability of repair kits of fuel fine filter (FFF) in contact with natural vegetable oils. The paper discusses the study of the reliability of repair kits (rubber technical products) of a diesel engine FFF, which were aged for 6 months in commercial diesel fuel, rapeseed and soybean oils.

AIM: Defining the durability and sustainability of the repair kit of the fine fuel filter of the YaMZ 236, 238, 240 diesel engines, which were aged for 6 months in commercial diesel fuel, rapeseed and soybean oils.

METHODS: The application of the repair kit of a diesel engine FFF in commercial diesel fuel, rapeseed and soybean oils is considered. The necessity of conducting research on the durability and sustainability of repair kits in vegetable oils is justified. The obtained research results were studied, the elastic-strength properties of the repair kit of the fine fuel filter for the fuel system of the YaMZ 236, 238, 240 diesel engines aged for 6 months in vegetable oils (rapeseed, soybean oil) and diesel fuel were determined with the results of a new sample. The authors conducted research using the RKM 20.2 universal testing machine, verification certificate no. C-DUP/29-09-2023/283528415 dated 09/29/2023. The tests were conducted at JSC “NEW REGISTER” testing center, Elektrostal, Moscow region.

RESULTS: The studies of the durability and sustainability of the repair kit (rubber technical products) of the FFF of the YaMZ 236, 238, 240 diesel engines fuel system have shown that the commercial diesel fuel impacts on the repair kit during six months and destroys it because of the additives contained in the commercial diesel fuel leading to oxidation and decrease in the service life of the repair kits [9, 10].

CONCLUSION: According to the results of the study, this is explained by the fact that the commercial diesel fuel contains additives, which lead to the concurrent oxidation process of the FFF repair kit in the commercial diesel fuel and leads to a decrease in the service life of repair kits.

BACKGROUND: One of the prerequisites for implementation of the mini-till and the no-till technologies is accumulation of mulch layer. Chain harrows show high efficiency in soil mulching, but the working bodies used on them are not fully capable of providing sufficient depth of cultivation, as well as crushing and mixing of crop residues with soil. Taking into account the high prospectivity of the mini-till and the no-till technologies, the research aimed at improving machines for soil mulching and chain harrows in particular is relevant.

AIM: Development of the wide-level chain harrow and the working body ensuring intensification of soil mulching processes, theoretical and experimental evaluation of traction resistance of the machine.

METHODS: Based on methods of agricultural mechanics, the research of traction resistance value of the harrow with the improved chain working body has been carried out. The laboratory-field experiment on estimation of traction resistance value of the wide-level chain harrow was carried out.

RESULTS: Based on the analysis of drawbacks of the default working body of the V.I. Dvurechensky’s chain harrow, it was proposed to move the ripper tooth to the fixing plate located in the center of the link. This technical solution is designed to provide better burial of the teeth in the soil, as well as the intensity of shredding of plant residues. It is theoretically and experimentally found that the value of traction resistance of the improved chain working body depends on the weight and the main design parameters of ripper teeth: length, tooth sharpening angle and cross-sectional diameter. The conducted laboratory-field experiments helped to find that at changing the working velocity of the machine from 15 to 21 km/h, the value of traction resistance increases from 26.2 to 32.3 kN, respectively, with the value of tractor slip not more than 3.0%. Based on the analysis of the obtained values of traction resistance and agrotechnical indicators of operation, the reasonable velocity of the machine is determined and should be 18 km / h.

CONCLUSION: The value of traction resistance of the chain harrow with the improved working organ has been experimentally determined, which allows recommending a tractor of a reasonable traction class. The efficient technological mode has been revealed.