A possibility has been investigated to diagnose the condition of a cylinder-piston group in the diesel engine KamAZ-740.63-400 for trucks KamAZ-6460 after a 60,000 km run. The following diagnosing parameters have been selected: a crankcase gas pressure, the compression and vacuometric properties of a cylinder-piston group. A special feature of these mated parts is that they maintain the normal combustion process in the diesel engine cylinders, as well as its resource. We have determined the boundary limits for diagnosing a crankcase gas pressure ‒ 2.39‒2.41 KPa. Based on data about the crankcase gas pressure, the examined trucks revealed malfunctions on the runs of 36,000 km, 48,000 km, 60,000 km. Given the rules for assessing the characteristics of compression-related faults, the minimum compression value for the diesel engines was 30.05 MPa or its difference among the cylinders did not exceed 10–12 %. The data on compression helped detect faults after 48,000 km run and 60,000 km run. We have determined the boundaries of wear based on the vacuometric parameters: maximum vacuum – 69–86 KPa; residual vacuum – 26–41 KPa. Control of the vacuometric properties of a cylinder-piston group has revealed faults in the diesel engines over their run interval of 36,000–60,000 km. An entropy approach has been applied to estimate the informativeness of the appropriate diagnosing parameters in bits. The informativeness level of a crankcase gas pressure is 0.329 bits, compression in cylinders – 0.249 bits, vacuometric indicators – 0.582 bits. This study allows the rational formation of the diesel engine condition diagnosing complexes during technical operation, as well determining the prerequisites for malfunctions. The data acquired are important for transportation and service enterprises and companies that manage freight vehicles

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Development of a system for determining the informativeness of the diagnosing parameters for a cylinder­piston group in the diesel engine during operation

The paper reports an analysis into tribological efficiency of mating parts "polymeric-composite materials ‒ steel" is carried out. Improperly selected materials produce significant operating costs in terms of tribology. Therefore, selecting the type of polymeric-composite materials to be used in the structures of nodes and machine parts is a task related to substantial improvement of their technical level. The testing of samples made from polymeric-composite materials for relative abrasive resistance when mated with samples made from steel 45 has made it possible to establish that the lowest value for weight wear was demonstrated by material Nylon 66. Among the examined materials, the closest to Nylon 66 in terms of the values for relative abrasive resistance is the material PA-6-210KS that demonstrated the values that are 1.65 times less. During operation of machines, in the presence of abrasive wear, it is advisable to mate the materials "Nylon 66 – steel 45" and "PA-6-210KS – steel 45". The results from a tribotechnical study without lubrication at the friction machine SMC-2 for the mating parts "polymeric-composite material – steel 45" make it possible to establish that the least wear was demonstrated by sample made from the material UPA-6-30, that is 0.00083 g. In terms of wear resistance, the closest to it is a sample from the material PAG/6.6 R196-GF30, which is 6.1 times greater for weight wear. The sample made from steel 45 mated with a sample from the material UPA-6-30 has the lowest value of weight wear, 0.00005 g. At the same time, the lowest value for the friction coefficient is demonstrated by the mated materials "steel 45 – UPA-6-30", 0.163. The progress of the mating process is achieved fastest, after 20 minutes, when using the material UPA-6-30 at a temperature in the friction zone of 348±2 K. Our research is necessary to substantiate further utilization and selection of polymeric-composite materials for mating parts working under difficult conditions. The current study is of interest to manufacturers of agricultural and quarry machinery and various transport machines.

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Analysis of tribological efficiency of movable junctions "polymeric­composite materials ‒ steel"

This paper reports a comparative study of the polymeric materials operating in conjugation with steel. In agricultural engineering, a significant role in structural materials belongs to polymer composites. This type of material is characterized by the low price, small technological cost, as well as acceptable processing characteristics. It has been found that it is necessary to form, for each type of mated parts, a set of materials that could maximally meet the operational conditions. To describe the operating conditions in more detail, they need to be generalized for the specific tribological and loading characteristics. Based on this, such load regimes were selected that correspond to the movable mated parts in sowing complexes. For these mated parts, it was necessary, in the course of the tribological study, to choose a material with minimal technological deviations but with enhanced tribotechnical characteristics. The result of this study has established that under the predefined conditions a polymer-composite material with the high-modulus filler PA-6.6+30 % F demonstrates the best tribophysical characteristics compared to the material PA-6.6. The proposed material, in conjugation with steel 1.1191, has a friction coefficient that is 38...41 % lower, while the temperature in the contact area is 8...12 % less, than that in conjugation with the material PA-6.6. Based on the metallographic analysis of friction surfaces, one can argue that a polymer composite with a high-modulus filler creates favorable conditions for their implementation in the moving units of machines. The results reported here make it possible to analyze and synthesize composite materials primarily for agricultural engineering, taking into consideration their tribological properties. The findings may be particularly interesting for service departments and enterprises producing parts for sowing complexes

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Design of mated parts using polymeric materials with enhanced tribotechnical characteristics

We present the results of the study of a nature of damages of three-cone rock bits that have premature lost their workability. Physical-mechanical and metallographic indices of melting steel of cone bit with brittle fracture are established. The distribution of carbon concentration and hardness in hardened carburized layers of cone bit is studied. Metallographic analysis of the most common steels used in the worldwide practice of cone bits manufacturing is performed to find ways to prevent premature loss of cone bits’ workability. The chemical composition and physical-mechanical and technological parameters are established, on the basis of which the conceptual requirements for the choice of steel and the quality of the technology of cone bits’ strengthening are formulated for domestic production.

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Analysis of Causes and Preventing Ways of Early Workability Loss of Three-Cone Rock Bit Cutters

With the development of dispersed systems in tribology, there emerged a possibility to use effectively functional additives to lubricants in the form of geomodifiers. When introducing composite oils with geomodifiers, it is not necessary to perform constructive changes in mated machine parts, however, their wear resistance and alignment increase. This requires experimental tribological research. It was proposed to use geomodifiers KGМF-1+oleic acids as a functional additive to motor oil, fresh oil Monnol TS-5 UHPD 10W40 and composite oil Monnol TS-5 UHPD 10W40+XADO HighWay for Diesel Truck (2.0...2.3 %) were chosen for comparison. An increase in friction momentum of different mated samples in the studied oils was recorded on the friction machine of 2070 СМТ-1 model with the additional module "ring – ring". Wear intensity in the samples in the studied oils was determined using the method of measuring the amplitude of the acoustic signal directly from the friction zone with the help of the device produced by Bruel&Kjear company. It was found that an increase in effectiveness of the oil compositions is observed in the following order: Monnol TS-5 UHPD 10W4, Monnol TS-5 UHPD 10W40, Monnol TS-5 UHPD 10W40+XADO HighWay for Diesel Truck, Monnol TS-5 UHPD 10W4+KGМF-1+oleic acid. The indicator of wear of the metal samples in the medium of modified oil Monnol TS-5 UHPD 10W4+KGМF-1+oleic acid, in comparison with basic oil decreased by 11.5...14.3 %. The value of critical load increased by 17.2 % and welding load increased by 19.3 %, respectively. In turn, it was found that maximum intensity of wear of the sample when using modified oil Monnol TS-5 UHPD 10W4+KGМF-1+oleic acid decreased by 3.4...6.0 times. The obtained data are necessary for the formation of composite oils and substantiation of conditions of their further operation during the period of forced alignment of parts tribojunction

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Studying the Tribological Properties of Mated Materials C61900 - A48-25BC1.25BNo. 25 in Composite Oils Containing Geomodifiers

Increase of wear resistance of different types of tribomating which are functioning in fluid lubrication is possible due to: choosing more expensive and high quality material of samples that is not always sensible; applying some wear resistant coatings on them; selection and formation of complex composition of oil additives. Due to nanomaterials development there is a possibility of efficient use of functional additives such as geo modifiers in tribology. Due to geo modifier-based oil composites use it’s not necessary to make any structural changes of machines mated parts though their wear resistance is increased. It requires the conducting of some experimental tribological research. It was found that oil media modified by a geo modifier increase the wear resistance of working surfaces of different types of tribomating. The use of geo modifier КGМF-1 (Katerynivka friction geo modifier -1 (patent of Ukraine No69657)) has been suggested. Lubrication quality of oil compositions based on М-10Г2К (M-10G2K) (motor oil of 10th viscosity grade, of group Г2К (G2K), for the CIS countries the oil grade conforms SAE 30) + КGМF-1 (4.0 4.5%) has been studied on a computer modernized four-ball friction testing machine ЧШМ-К1 (CHMK-К1). To evaluate the lubrication quality of the oil composite with the suggested geo modifier and to use the comparative analysis of the obtained results the research was conducted on commercial samples of base oil M-10G2K and oil composites M-10G2K + XADO Maximum for Diesel Truck (2.0 2.3%) (agent 2D sliding revitalization factor (RF) 100, revitalizant 1 Stage RF 100, metal conditioner RF 5.5), M-10G2K + cuprum glycerate (3.7 4.5%). Some average indices of wear, critical load, and welding load have been found. Samples division into 4 types of mating according to the following characteristic features: mobility, material hardness and friction area has been suggested for more accurate picture of wear resistance changes of samples tribomating which are functioning in base and modified oil. Lower friction torque of different samples couplings in modified oil by geo modifier КGМF1 in comparison with base oil M-10G2K was recorded while using Friction machine 2070 SMT-1 with add-on module "ring-ring". The samples wear rate in modified oil by geo modifier КGМF-1 in comparison with base oil M10G2K was studied by method of acoustic signal amplitude measurements directly from the friction zone by a commercially produced instrument of Brüel & Kjear company. Corresponding author: V. Aulin Central Ukrainian National Technical University, 8 Universytetskyi ave., 25006 Kropyvnytskyi, Ukraine. E-mail: AulinVV@gmail.com R E SE A R C H V. Aulin et al., Tribology in Industry Vol. 41, No. 2 (2019) 156-165 157 It was found that efficiency increase of the oil compositions under investigation is taking place in the following order: M-10G2K + XADO Maximum for Diesel Truck, M-10G2K + cuprum glycerate, M-10G2K + КGМF-1. Wear index due to the use of modified oil M-10G2K + КGМF-1 was 19 20 % lower comparing to the obtained data of the base oil, critical load value was 27 29 % larger, and welding load – 24 25% larger respectively. Moreover, it was recorded that the maximum wear rate of samples in their functioning in modified oil M-10G2K + КGМF-1 was 3 times lower, and friction torque change law is similar to the wear rate change depending on the time of testing. © 2019 Published by Faculty of Engineering

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Wear resistance increase of samples tribomating in oil composite with geo modifier КGМF-1

Increase of wear resistance of different types of tribomating which are functioning in fluid lubrication is possible due to: choosing more expensive and high quality material of samples that is not always sensible; applying some wear resistant coatings on them; selection and formation of complex composition of oil additives. Due to nanomaterials development there is a possibility of efficient use of functional additives such as geo modifiers in tribology. Due to geo modifier-based oil composites use it’s not necessary to make any structural changes of machines mated parts though their wear resistance is increased. It requires the conducting of some experimental tribological research. It was found that oil media modified by a geo modifier increase the wear resistance of working surfaces of different types of tribomating. The use of geo modifier КGМF-1 (Katerynivka friction geo modifier-1) has been suggested. Samples division into 4 types of mating according to the following characteristic features: mobility, material hardness and friction area has been suggested for more accurate picture of wear resistance changes of samples tribomating which are functioning in base and modified oil. Lower friction torque of different samples couplings in modified oil by geo modifier КGМF-1 in comparison with base oil M-10G2K was recorded while using Friction machine 2070 SMT-1 with add-on module "ring-ring". The samples wear rate in modified oil by geo modifier КGМF-1 in comparison with base oil M-10G2K was studied by method of acoustic signal amplitude measurements directly from the friction zone by a commercially produced instrument of Brüel & Kjear company. Moreover, it was recorded that the maximum wear rate of samples in their functioning in modified oil M-10G2K + КGМF-1 was 2...3 times lower, and friction torque change law is similar to the wear rate change depending on the time of testing.

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Wear resistance increase of samples tribomating "Steel 45-cast iron SCH20" with geo modifier KGMF-1

In this paper, the laws of the electrochemical - mechanical running-in (ECMR) are considered. For elimination of inaccuracies of form of details and errors of assembling mechanism expose to running-in which running- in of the surfaces take place. The most effective factor of acceleration of running-in is to use the combined processes at running- in surfaces. One of them is ECMR..
The results of experimental studies have shown that the the processes of ECMR pass in the environment of electrolyte, which influences efficiency of process, mode of friction at running-in pair and speed of electrochemical reactions. The essence of  ECMR consists of the following: working motion for details of mechanism is given, between details an electrolyte is pumping and cutoff alternating current. Due to joint electrochemical-mechanical influence there is a rapid adaptation of one surface to other. The most effective factor of  ECMR is electrochemical, at which it is easy to electrochemical stripping of material from the run-in surface due to anodal dissolution at the hydrodynamic lubrication rate.

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Features of electrochemical-mechanical running-in of chrome-plated piston rings to the cast-iron surface of the cylinder liner under different friction modes

А. Є. Чернай

Papers

Wear resistance increase of samples tribomating in oil composite with geo modifier КGМF-1

Wear resistance increase of samples tribomating "Steel 45-cast iron SCH20" with geo modifier KGMF-1

Features of electrochemical-mechanical running-in of chrome-plated piston rings to the cast-iron surface of the cylinder liner under different friction modes