piston head
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The article presents the results of an experimental study and analytical evaluation calculations to check service life and increase durability of the needle bearing of piston head of connecting rod of a transport diesel engine. The primary reasons for the violation of the nominal operation of the main units of this mechanism have been established. Corresponding recommendations are proposed for carrying out accelerated tests for durability, reducing the thermal loads of the bearing operation and, as a consequence, improving the quality and service life of its entire piston group. Theoretical and experimental methods for determining the nominal life of the needle bearing of the piston head of the connecting rod (PHCR) of a transport diesel engine are proposed. The theoretical methodology allows obtaining reliable values of durability, taking into account the distribution of the working load over the rolling elements, as well as the mobility of the piston pin and sleeve. The performed calculations make it possible to correct and clarify the standard mathematical model for determining the nominal life of the PHCR needle bearing, depending on the distribution of loads on the rolling elements (rollers) under different operating conditions. This experimental technique with an acceleration factor of 10 is based on a twofold increase in the force effect on the elements of the PHCR needle bearing. This was achieved by assembling the bearing using a special technology, which is described in detail in the work. A significant decrease in the thermal effect and a decrease in radial loads on working rollers have been established. For ensure the regular oil supply into bearing during engine operation, a technique was developed to increase the load on the roller in contact zone, which significantly influenced durability and made it possible to conduct accelerated tests with a reliable yield. Its results of operational research and experience in design work correlate and are sufficiently explained by the developed methods, which allows them to be used for the improvement and modernization of connecting rods with needle bearings in PHCR. That is a permission to use these methodic for doing perfect and modern the needle bearing of the connecting-rod piston. Keywords: diesel, test procedure, needle bearing, rollers, piston head of the connecting rod, durability.

This paper presents the assessment of different piston head geometry made of aluminum and magnesium alloy. ANSYS finite element analysis is used to analyze the piston under static and transient conditions. Round and flat piston head is constructed using SOLIDWORK software and the exported to ANSYS WORKBENCH. According to static analysis, it is found that flat head piston produced higher stress compared with round head piston. Similar trend is observed when transient analysis is conducted where round piston head capable to produce almost stress consistency with respect to time.

Abstract The piston performance may be impacted by piston geometry, stress, temperature and deformation applied. Thus, the purpose of this study is to investigate the changes of piston performance with different piston head designs. Besides, the piston is optimized by using topology optimization to remove excessive material. The study was carried out by using the dimension of a piston based on the cylinder of a spark ignition engine. The four piston head designs are flat-top piston, bowl piston, square bowl piston and dome piston. All four piston designs were modelled by using Solidworks. Static Structural and Steady State Thermal Analysis in ANSYS Workbench were used to analyze the piston performance. The measured parameters are stress, deformation and temperature distribution. Next, optimization of piston was done by using topology optimization to identify non-essential parts that can be removed. The optimized piston design was analyzed. The findings for the original and optimized piston geometries were tabulated to make comparison. It is found that bowl piston has lower stress, deformation and temperature. The stress, deformation and temperature of optimized piston is lower than original piston. The mass of optimized piston is about 5 percent lesser than the original piston.

Abstract This paper discusses the process of formation of an oxide coating (hardening and heat-insulating coating) on the working surfaces of the head (top and piston grooves) of the piston by the method of microarc oxidation (MAO). In the process of oxidation of the piston head, the operating parameters of MAO will have a significant effect on the thickness and porosity of a formed oxide coating. The paper presents the theoretical relationships between the electrical parameters of the microarc oxidation mode and the thickness and porosity of the oxide coating. The thickness of the formed oxide coating on the piston heads will depend on the applied voltage and the composition of the electrolyte used. The porosity of the formed oxide coating will depend on the parameters of the current strength and the applied voltage. It is theoretically established that the formation of an oxide coating of a certain thickness and porosity occurs due to changes in the current strength, voltage and time of microarc oxidation.

The process of formation of an oxide coating (strengthening and heat-insulating one) on the working surfaces of the piston head (piston bottom and grooves) using the method of micro-arc oxidation (MAO) is discussed. It is noted that during the oxidation of the piston head, the MAO process conditions will have a significant effect on the thickness and porosity of the oxide coating formed. The theoretical dependences of the influence of the electrical parameters of the microarc oxidation process conditions on the thickness and porosity of the oxide coating are presented. It has been found that the thickness of the oxidized layer will be directly proportional to the voltage and composition of the electrolyte, and the porosity is inversely proportional to the voltage and directly proportional to the current strength. It is shown that by varying the parameters of the oxidation conditions (current strength, voltage and process time), oxidized layers of the required thickness and porosity can be obtained.

Abstract The article discusses the reasons of fatigue failure of pistons of high-loaded diesel engines. A deformation-kinetic criterion is proposed, generalized to non-isothermal loading, which allows more correct calculation of the number of thermal loading cycles before the appearance of fatigue damage. For a specific implementation of the proposed criterion, a calculated assessment of the piston stress-strain rate was carried out using the FEM. The boundary conditions for the calculation were obtained by thermometry of the piston head on a non-motorized thermal stand (TS). Comparison of the calculated and experimental values of the number of thermal cycles before the appearance of cracks on the edge of the combustion chamber (CC) of pistons made by casting and isothermal stamping is given.

The paper aims to analyse the demands of four-stroke naval pistons. To begin with, a brief analysis of the evolution of shipbuilding was made. Mechanical requests are produced by the gas pressure force and inertial force of the alternate moving masses. Under its action the piston suffers an axial deformation. The thermal demands appearing in the engine are all the more important as the engine power is higher. The possibility of calculating them is more difficult due to the complexity of the thermogazodynamic phenomena in the engine cylinder. Thus, in the piston head, which comes in contact with both the hot gases and the fresh (much cooler) load, a non-stationary heat flow is installed which leads to a certain thermal regime of the engine. Considering the demands outlined in the last chapter, they lead to the final conclusion that although the most unfavourable loading situation was considered as the maximum pressure during the processes and even exaggerated in establishing the working conditions, the piston is still close to the elastic limit. This demonstrates that the way of calculating the dimensions of the piston is correct and safe, as long as its constructive dimensions are not oversized.

This paper is a review outline of references of CI engine (Combustion Ignition Engine) journals. CI Engine is the most preferred sort of engine as a result of its high thermal efficiency than any other internal or external combustion engine. Due to the demand for petroleum fuel, increasing cost, and hazardous emission by CI Engine, it is required to enhance the performance, combustion, and emission characteristics of CI Engine. Bio-fuels are well-tried to be superb substitutes for the present diesel. Nowadays, numerous researches are going on in biodiesel blends at varying ratios to increase the performance of the engine. Also many researches are going on coating the piston head in order to reduce the black smoke at the exhaust.

Biofuels represent an energy option to mitigate polluting gases. However, technical problems must be solved, one of them is to improve the combustion process. In this study, the geometry of a piston head for a diesel engine was redesigned. The objective was to improve the combustion process and reduce polluting emissions using biodiesel blends as the fuel. The methodology used was the mechanical engineering design process. A commercial piston (base piston) was selected as a reference model to assess the piston head’s redesign. Changes were applied to the profile of the piston head based on previous research and a new model was obtained. Both models were evaluated and analyzed using the finite element method, where the most relevant physical conditions were temperature and pressure. Numerical simulations in the base piston and the new piston redesign proposal presented similar behaviors and results. However, with the proposed piston, it was possible to reduce the effort and the material. The proposed piston profile presents adequate results and behaviors. In future, we suggest continuing conducting simulations and experimental tests to assess its performance.

Turmeric leaves are waste products after removing turmeric rhizome. In the present work, the oil was extracted from the leaves of curcuma longa by hydro distillation method. The extracted oil was studied for preliminary physicochemical and phytochemical tests. The phytochemical evaluation of the turmeric leaf oil indicates the presence of terpenes which was used to run two stroke and four stroke engines. Engine emits less harmful product with turmeric oil as compared to petrol. Hence, it has been concluded that the turmeric leaf oil can be used as an alternative biofuel for petrol. Theoretically, turmeric leaf oil properties are similar to that of petrol. By performing practical experiments on this oil using different types of piston head shapes and varying parameters, we came to know that this will fulfil all capabilities as a biofuel in IC engines. In the second part, the characteristics fuel properties of turmeric leaf oil and their blends with petrol in the proportion of 40:60 (B40) have been studied. In the third part, engine tests have been conducted on turmeric leaf oil blends with petrol oil and brake thermal efficiency, engine gas temperature and air fuel ratio were evaluated. The next part consists of exhaust emission tests such as CO and HC emission measurement with a five gas analyser.