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In order to enhance the stability of the turbocharger rotor system, the nonlinear dynamic characteristics of the turbocharger supported by tilting pad journal bearings are analyzed in this study. After the nonlinear oil film force model for tilting pad journal bearings is derived based on the short bearing approximation and considering the circumferential swinging of the pads, the nonlinear vibrations of the turbocharger supported by tilting pad journal bearings subjected to unbalanced excitation are investigated. Through an analysis of the vibration response of the rotor system at various rotational speeds, it was observed that the turbocharger rotor system supported by tilting pad journal bearings demonstrates improved stability performance in comparison to the other types of bearings in existing studies. The turbocharger exhibits stable periodic motion at low to medium rotational speeds and quasi-periodic motion at high rotational speeds. What's more, the impact of bearing parameters on the nonlinear dynamics characteristics of the turbocharger rotor system is discussed. Results from the discussion of bearing parameters indicate that increasing the pad preload, oil film viscosity, and pad angle, and reducing the radial clearance when the relative eccentricity is small can all increase the bifurcation point speed and enhance the system's stability. Furthermore, increasing the pad angle suppresses the amplitude of sub-synchronous vibrations in the rotor system. The research findings provide some suggestions for the design considerations for tilting pad bearings applicable to turbochargers. [ABSTRACT FROM AUTHOR]

This article assesses the technical condition of the air supply system of the Ford Transit commercial vehicle. After the analysis, results were obtained that allow identifying the reasons for the failure of the intake system of the diesel engine with the Euro5 emission standards. It was found that the malfunction of the turbocharger directly affects the overall condition of the engine and its performance characteristics. The main failures are associated with the malfunction of the turbocharger itself and the leakiness of the pipes or intercooler. The probabilities of occurrence of these failures are determined for the Duratorq TDCi 2.2 engine. [ABSTRACT FROM AUTHOR]

Limited by the poor transient response performance of turbochargers, the dynamic performance of aviation piston engines tends to deteriorate. In a bid to enhance the turbocharger's acceleration capabilities, this study scrutinizes various factors impacting its performance. Based on the operational principles and transient response process of the turbocharger, three types of inertia—namely, aerodynamic inertia (ADI), thermal inertia (TI), and mechanical inertia (MI) — are identified and addressed for design. To begin, this paper pioneers the innovative definition of a method for evaluating the transient response performance of the turbocharger. This method incorporates the introduction of an ADI parameter, inspired by the definition of MI. Subsequently, a thin-walled volute design with a low Biot number and a lightweight turbine impeller is introduced to reduce the turbocharger's TI and MI. The simulation results of the flow field distribution within the volute and diffuser demonstrate the comprehensive design method's effectiveness in improving gas pressure and temperature distributions in these components. Notably, the pressure distribution fluctuation in the constant moment-of-momentum volute (CMV) is 62.8% lower than that in the constant velocity moment volute (CVMV). The low-TI thin-walled volute not only enhances the turbocharger's response speed but also reduces its weight by approximately 40%. The impact of three types of inertia on the engine's response speed is quantified as follows: ADI (94%) > MI (5%) > TI (1%). This conclusion has been verified through test results of both the turbocharger and the engine. This design method not only significantly improves the turbocharger's response performance but also offers valuable insights for the optimal design of other blade mechanical systems.

Turbocharger fouling phenomenon was analyzed from the risk assessment perspective in this study. The research employed exhaust system and turbocharger equipment of commercial ship that equipped with a Doosan-MAN B&W 6S50 MC-C diesel engine was used as the main research materials, and utilized the fuzzy Failure Mode and Effects Analysis (FMEA) based on the expert system as a methodical approach. The experts revealed different types of turbocharger fouling failure modes (FMs), along with their respective causes and subsequent consequences. Following that, the specialists allocated an O, S, and D score to each FM. Within the framework of fuzzy logic, the process entails the establishment of input and output membership functions, as well as the construction of a fuzzy model incorporating an inference mechanism and a rule base. Based on the analysis findings, the three primary factors are as follows: low cylinder compression pressure with a Fuzzy Risk Priority Number (FRPN) score of 6.95, high main engine fuel oil consumption with a score of 6.92, and high CO, CO2, SOx emissions with a 6.45. The phenomenon of turbocharger fouling, being an inherent occurrence, has significant ramifications on the main engine, the vessel as a whole, and the ecological surroundings. The quantitative results presented in this study provide valuable insights into the risks associated with maritime endeavors. The data generated from this research can be used by stakeholders in the maritime industry to better understand this situation and take proactive measures to mitigate potential risks in the future. Furthermore, the findings of the research provide corroboration for the implementation of predictive maintenance procedures. [ABSTRACT FROM AUTHOR]

This paper presents the research results on the strength of materials and power of the Toyota 3C engine when changing the structure and number of blades of the compressor wheel in the turbocharger. 3D models of different compressor wheels were created using reverse engineering and then simulated in the ANSYS environment with turbine shaft rotation speeds of 10,000, 15,000, and 20,000 rpm, respectively, to examine the strength of the compression wheel materials. To evaluate engine power, compressor wheels were machined on a 5-axis CNC milling machine. The MP 100S specialized test bed was used to perform experiments and compare engine power when using the original and alternative compressor wheels of the CT9 turbocharger. The compressor wheels were made of aluminum alloy, with a structure and number of blades selected to ensure durability when working. The CT9 turbocharger has a four-pair blade compressor wheel that consistently delivers higher engine power than in other cases. [ABSTRACT FROM AUTHOR]

The compressor volume flow rate model determines the mass flowing into the diesel engine in simulation. It is a key component model that affects the accuracy of the overall performance of the diesel engine. At present, there is a lack of an accurate and easy-to-use compressor volume flow rate model. To solve this, the stagnation enthalpy-based compressor volume flow rate model (SP model) is proposed. The SP model is compared with an improved version of the famous empirical JENSEN model, M-JENSEN (MJ), and physics-based KS model. The proposed SP model only requires the stagnation pressure to be determined. The empirical M-JENSEN model needs a compressor map to optimize its six parameters. The physics-based KS model requires specific work to be determined. The SP model needs the least measured data and is easy to be identified. Models' accuracy comparison on ABB A270 shows that the proposed SP model can generate the compressor map with RMSE of about 1.1m3/s and mean relative error (MRE) of about 6.9%. The rated volume flow rate of ABB A270 is about 20m3/s. While the RMSE and MRE of MJ model are about 0.6m3/s and 3.1% respectively. And they are about 3.0m3/s and 17.4% for KS model. When the model's accuracy is compared to MAN TCA88, SP model shows slightly better performance than its performance on ABB A270. The rated volume flow rate of MAN TCA88 is about 60m3/s. The values of RMSE of SP model, MJ model, and KS model are 3.2m3/s, 2.2m3/s, 10.3m3/s respectively. Their MREs are 6.73%, 4.45%, and 17.8% respectively. In terms of these results, it can be concluded that our proposed SP model needs the least data, easy to code, and has excellent performance. It is one of the best compressor mass flow rate models so far in real-time diesel simulation. [ABSTRACT FROM AUTHOR]

Understanding the flow instabilities encountered by the turbocharger compressor is an important step toward improving its overall design for performance and efficiency. While an experimental study using Particle Image Velocimetry was previously conducted to examine the flow field at the inlet of the turbocharger compressor, the present work complements that effort by analyzing the flow structures leading to stall instability within the same impeller. Experimentally validated three-dimensional computational fluid dynamics predictions are carried out at three discrete mass flow rates, including 77 g/s (stable, maximum flow condition), 57 g/s (near peak efficiency), and 30 g/s (with strong reverse flow from the impeller) at a fixed rotational speed of 80,000 rpm. Large stationary stall cells were observed deep within the impeller at 30 g/s, occupying a significant portion of the blade passage near the shroud between the suction surface of the main blades and the pressure surface of the splitter blades. These stall cells are mainly created when a substantial portion of the inlet core flow is unable to follow the impeller's axial to radial bend against the adverse pressure gradient and becomes entrained by the reverse flow and the tip leakage flow, giving rise to a region of low-momentum fluid in its wake. This phenomenon was observed to a lesser extent at 57 g/s and was completely absent at 77 g/s. On the other hand, the inducer rotating stall was found to be most dominant at 57 g/s. The entrainment of the tip leakage flow by the core flow moving into the impeller, leading to the generation of an unstable, wavy shear layer at the inducer plane, was instrumental in the generation of rotating stall. The present analyses provide a detailed characterization of both stationary and rotating stall cells and demonstrate the physics behind their formation, as well as their effect on compressor efficiency. The study also characterizes the entropy generation within the impeller under different operating conditions. While at 77 g/s, the entropy generation is mostly concentrated near the shroud of the impeller with the core flow being almost isentropic, at 30 g/s, there is a significant increase in the area within the blade passage that shows elevated entropy production. The tip leakage flow, its interaction with the blades and the core forward flow, and the reverse flow within the impeller are found to be the major sources of irreversibilities. [ABSTRACT FROM AUTHOR]

Copyright of China Mechanical Engineering is the property of Editorial Board of China Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The potential for ammonia/hydrogen (NH 3 /H 2) blends as fuel in modern, turbocharged, gas engines is evaluated by comparing the combustion properties of these blends with those of methane. To ensure proper combustion phasing in existing spark-ignited (SI) engines, the laminar burning velocity (LBV) is used, while the ignition delay times (IDT) of the mixtures are compared to assess the risk of engine knock. The chemical mechanisms used for the computation of IDT and/or LBV of NH 3 /H 2 mixtures are selected from 8 chemical mechanisms based on their ability to predict experimental data. The application of a turbocharger is shown to "boost" the temperature in the cylinder after compression to values that admit the use of NH 3 /H 2 mixtures in natural-gas SI engines without increasing the compression ratio (CR). The analysis also identifies regions of temperature and H 2 fraction that increase the risk of knock. Using the conditions in a practical turbocharged SI engine as an example, 40–50% H 2 in NH 3 yields combustion phasing equivalent to that obtained with methane, while avoiding the risk of knock. Analysis of the IDT for the conditions in a high-pressure direct-injection natural-gas engine also shows that the use of a turbocharger in compression-ignition (diesel-type) engines strongly reduces the demands on CR for achieving the conditions necessary for reliable ignition of NH 3 /H 2 mixtures. Increasing the temperature by only a few tens of degrees above the conditions studied will yield an IDT for ∼20% H 2 in NH 3 that satisfies the ignitibility requirements for use in a turbocharged diesel engine. • Turbocharging facilitates the use of NH 3 /H 2 mixtures in gas engines. • The risk of engine knock limits the "boost" temperature and maximum H 2 fraction. • 40–50% H 2 in NH 3 mimics CH 4 combustion without knocking in the SI engine considered. • Modest preheating enables the use of NH 3 with 20% H 2 in a turbocharged CI engine. • The methodology used is readily applied to different fuels and engine conditions. [ABSTRACT FROM AUTHOR]

In harsh environments, turbochargers require continuous adjustment of the rotating speed, which can lead to differences in erosive wear on the blades compared to erosive wear under constant speed conditions. In this study, the erosion model expression for an aluminum alloy plate with a fitted Ks value of 20 μm under the erosion of 160 μm SiO2 particles is obtained through erosive wear experiments. Taking a turbocharger compressor as the research object, the influence of four commonly used working speeds on blade wear is analyzed. The results show that when the speed increases from 70,000 rpm to 130,000 rpm, the maximum wear rate concentration values for the main and splitter blades increase by approximately 590% and 310%, respectively. Finnie erosion model of real compressor blades was fitted through experiments. The working speed has a significant impact on the particle trajectory. As the speed increases, the wear area of the main blade gradually concentrates. As the speed increases, the wear area of the diverter vanes decreases abruptly. [ABSTRACT FROM AUTHOR]

Copyright of Railway Construction Technology is the property of Railway Construction Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The global push to reduce greenhouse gas emissions has led to the ban of high global warming potential (GWP) refrigerants in the refrigeration sector, prompting the adoption of low-GWP alternatives. However, as regulations are expected to tighten, technologies like the Reverse Brayton cycles (RBC) are emerging. RBCs can operate with safe fluids and can reach very low temperatures through compressions, regeneration, and expansion, requiring only electricity. This research presents results from an RBC equipped with a radial turbine using natural air (R-729), a hazard-free fluid with zero ozone depletion potential (ODP) and emission potential. The cycle utilizes automotive components, offering a cost-effective, high-tech solution. The study evaluates the cycle COP at a design point and performs an exergetic analysis at 173K. Using a thermal and fluid dynamic model of the cycle, the critical components of the cycle influencing the COP are identified, and potential improvements are explored. [ABSTRACT FROM AUTHOR]

The digital twin concept proves to be highly advantageous for smart ships as it allows the digital model to adapt in real time with changes in the physical ship. The mean value engine model (MVEM) is investigated with three different compressor mass flow rate models: a 2D interpolation model (2D), an experience-based M-JENSEN (MJ) model, and a physics-based Kang Song (KS) model. Each model is studied on a MAN 7S80ME engine with ABB A270 turbochargers. The root-mean-square errors (RMSE) for the test data are approximately 2.5 m 3 / s for the 2D model, 2.8 m 3 / s for the KS model, and 0.56 m 3 / s for the MJ model. For the training data, the RMSEs are around 0.0, 3.0, and 0.69 m 3 / s , respectively. When coupling each model to the MVEM, it is observed that the calculated values differ only in the turbocharger speed. The RMREs under steady-state processes are 0.54% for MVEM with the 2D model, 1.63% for MVEM with the KS model, and 0.48% for MVEM with the MJ model. Under dynamic processes where the engine load is changed from 100% to 80%, the RMREs are 1.59%, 2.40%, and 1.58%, respectively. Among the studied models, the 2D model exhibits instability, the MJ model shows the highest accuracy, while the KS model performs the worst. However, all models demonstrate comparable results when used in the MVEM. Moreover, the physics-based KS model is a favorable choice for digital twin applications due to its excellent extrapolation ability and low dependence on measured data. [ABSTRACT FROM AUTHOR]

Poor clearances, misalignments, and carbon deposits in a turbocharger due to high running hours can decrease engine efficiency. This study analyzes the effects of turbocharger reconditioning on the performance and emissions formation of a marine diesel generator engine. The engine test experiments were performed on a university training ship's auxiliary diesel engine with 4309 running hours before and after the TC overhaul. As a result, cylinder peak pressure was increased by a maximum of 3.57 % while fuel saving of 5–8 g/kWh was realized. Lower exhaust gas temperatures and improved charge air pressure by up to 7.7 % were recorded. A significant CO emission reduction of 21.6 % was recorded at idle load whereas NOx and CO2 emissions were reduced to a maximum of 4.86 % and 7.30 % at 50 % engine load. The results indicate that scheduled TC overhaul and maintenance are very useful to improve the engine’s fuel economy, and performance and reduce exhaust emissions.

The goal of the study is to elucidate the reasons for early fracture of the gear wheel teeth of a Cameron TA9000 turbocharger (1820 kW) after an operational load up to 1.3 × 109 cycles. The chemical composition and the microstructure of the tooth metal were studied using the methods of metallography, microhardness and optical microscopy. The microrelief of fracture surfaces of operational fractures was studied using electron scanning microscopy. Analysis of the chemical composition proved the steel grade of the tooth metal (DIN 31CrMoV9) declared by the manufacturer. Visual analysis of the fragments under study revealed numerous cracks present on the tooth contact surfaces. The origins of fatigue fracture detected on the fracture surfaces are typical of high cycle and gigacycle fatigue fracture. In the latter case, the detected fracture looks like a "fisheye" exhibiting an area of structural heterogeneity with inclusions and pores in the center. The fracture probably developed from the first tooth fragment to the fifth one, being accompanied by an increase in the number of origins of fatigue fracture known to be attributed to an increase in the stress amplitude. Metallographic study showed the presence of a subsurface hardened layer with a thickness of 120–200 μm with a defect-containing structure associated with grain-boundary precipitates (presumably, carbides (Fe, Cr)3C), which could have resulted from violation of the modes of heat treatment of the gear wheel. Formation of brittle intergranular cracks on the contact surface and their subsequent development in the entire depth of the subsurface hardened layer appeared to be the reason for a decrease in the strength and bearing capacity of the gear teeth. The interaction of the resulting cracks with longitudinal microcracks that originated from defects due to poor-quality mechanical processing of the gear led to the formation of centers of fatigue cracks, the development of which caused the final destruction of several teeth. [ABSTRACT FROM AUTHOR]

The surge limit of centrifugal compressors is a key parameter in the design process of modern turbochargers. Numerical methods like steady-state simulations are state-of-the-art methods for predicting the performance of the centrifugal compressor. In contrast to that, the determination of the surge limit with any numerical method is still an unsolved challenge. Since the extensive work of Greitzer and many other researchers in this field, it is well-known that surge is a system-dependent phenomenon. In the case of steady-state simulations, the simulation domain is chosen to be as small as possible due to the numerical cost. This simply implies that there is no system information included in the numerical model. Therefore, it is not possible to determine any system-dependent surge limit with today's applied numerical methods. To overcome this issue, an enhanced Greitzer surge model, which has been developed at Tu Darmstadt, should act as a link between the simulation and the system in which the compressor will be operated. The focus of this paper will rather be on the methodology of determining the surge limit by means of numerical data than on the surge model itself. The methodology will be validated by experimental data of different systems. [ABSTRACT FROM AUTHOR]

Understanding the flow instabilities encountered by the turbocharger compressor is an important step toward improving its overall design for performance and efficiency. While an experimental study using Particle Image Velocimetry was previously conducted to examine the flow field at the inlet of the turbocharger compressor, the present work complements that effort by analyzing the flow structures leading to stall instability within the same impeller. Experimentally validated three-dimensional computational fluid dynamics predictions are carried out at three discrete mass flow rates, including 77 g/s (stable, maximum flow condition), 57 g/s (near peak efficiency), and 30 g/s (with strong reverse flow from the impeller) at a fixed rotational speed of 80,000 rpm. Large stationary stall cells were observed deep within the impeller at 30 g/s, occupying a significant portion of the blade passage near the shroud between the suction surface of the main blades and the pressure surface of the splitter blades. These stall cells are mainly created when a substantial portion of the inlet core flow is unable to follow the impeller’s axial to radial bend against the adverse pressure gradient and becomes entrained by the reverse flow and the tip leakage flow, giving rise to a region of low-momentum fluid in its wake. This phenomenon was observed to a lesser extent at 57 g/s and was completely absent at 77 g/s. On the other hand, the inducer rotating stall was found to be most dominant at 57 g/s. The entrainment of the tip leakage flow by the core flow moving into the impeller, leading to the generation of an unstable, wavy shear layer at the inducer plane, was instrumental in the generation of rotating stall. The present analyses provide a detailed characterization of both stationary and rotating stall cells and demonstrate the physics behind their formation, as well as their effect on compressor efficiency. The study also characterizes the entropy generation within the impeller under different operating conditions. While at 77 g/s, the entropy generation is mostly concentrated near the shroud of the impeller with the core flow being almost isentropic, at 30 g/s, there is a significant increase in the area within the blade passage that shows elevated entropy production. The tip leakage flow, its interaction with the blades and the core forward flow, and the reverse flow within the impeller are found to be the major sources of irreversibilities.

Gas flow in the seal system can be expected during the operation of a turbocharger and is associated with negative effects on the quality of the lubricant or turbocharger efficiency. Gas flow also affects particulate matter production due to lubricant entrainment in the compressor or turbine. The prediction of gas flow rates depends on many design parameters and the operating conditions of the turbocharger, but sufficiently accurate descriptions of the gas flow mechanisms and their quantification depending on the operating conditions have not yet been presented. The proposed computational approach simultaneously solves the gas dynamics in the seal system, the heat transfer in the turbocharger rotor-bearing system and the dynamics of the seal rings and rotor, including the bearings. The computational model for the turbocharger of a heavy-duty vehicle engine is experimentally validated. Two mechanisms have major influences on gas mass flow: the gas flow through the thin gap between the moving ring and groove and the flow through the ring gap. The results show that the importance of these mechanisms depends on several geometrical dimensions of the seal system and the operating conditions of the turbocharger, with a strong connection to the rotor dynamics and thermal load of the impellers. Influences involving rotor movement or rotor thermal conditions are crucial, and their non-inclusion limits the ability to correctly predict gas mass flow.

Copyright of Journal of Chongqing University of Technology (Natural Science) is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the concept of downsizing an internal combustion engine, the turbocharger in one of the key device for reducing emissions while maintaining engine performance. Turbine as one of the main components in a turbocharger has an important role in determining the power generated by an internal combustion engine. This paper presents the development of turbine components in turbocharger and methods of turbine design optimization. In order to maximize the performance of the turbine in the turbocharger, a variable geometry turbine (VGT) is used. VGT has several variations that have been developed such as Active Controlled Turbocharger (ACT), Passive Controlled Turbocharger (PCT), Variable Nozzle Turbine (VNT), and Regenerative Electrically Assisted Turbocharger (REAT). Another thing that can be developed to maximize turbine performance is to use a double-entry turbine. The double entry turbine has the aim of saving exhaust gas energy and facilitating cylinder gas exchange. One way to produce efficient turbine performance is to replace the existing spiral casing on the turbine with a multi-channel casing (MC). The use of this multi-channel turbine reduces the best efficiency points (BEP). [ABSTRACT FROM AUTHOR]

Copyright of Journal of Engineering for Thermal Energy & Power / Reneng Dongli Gongcheng is the property of Journal of Engineering for Thermal Energy & Power and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In response to the continually increasing thermal load caused by the rising gas temperature in the inlet of radial-flow turbines, this paper proposes the use of axial hole air-entraining cooling to cool the turbine shaft and turbo wheel back-disc. The cooling effect of this technique, as well as its influence on the aerodynamic performance of turbines, were investigated through numerical simulations. The results demonstrate that the axial hole air-entraining cooling technique can significantly improve the local cooling efficiency of the turbine back-disc. Under a blowing ratio of 0.25 %, the local cooling efficiency increased by 154 %, and the temperature decreased by up to 233 K. The maximum temperature on the surface of the turbine shaft at the floating bearing location decreased significantly, thus reducing the coking risk of the lubricating oil. When the blowing ratio was within 0.5 %, the impact of this cooling technique on the overall turbine performance was negligible. [ABSTRACT FROM AUTHOR]

The internal thread texture causes changes in the dynamic characteristics of the oil film of the semi-floating ring bearing, which affects the amplitude of vibration and operating life of the turbocharger rotor system. Based on the fluid lubrication theory, the oil film governing equation of a semi-floating ring bearing with surface texture parameters is derived. The effects of the texture depth, position, and number of turns of the internal thread on the dynamic characteristics of the bearing oil film, such as the maximum pressure, load-carrying capacity and stiffness damping, are analyzed. Taking a type of turbocharger as an example, a hydrodynamic model is established to analyze the oil film lubrication in the semi-floating ring bearings, and the dynamic characteristic of the oil film is analyzed by computational fluid dynamics method. The results show that the maximum pressure, bearing capacity, and stiffness damping coefficient of oil film increase firstly and then decrease with the increase of texture depth and the number of thread turns in the range of journal rotation speed from 1000 to 20,0000 r/min. Compared with the non-texture bearings, the dynamic characteristics coefficients of the oil film such as bearing capacity and stiffness damping increase the most, when the depth of texture is 0.006 mm and the number of thread turns is 9. Secondly, the dynamic characteristic coefficient of oil film is improved when the texture is distributed in the middle than on both sides. The thread texture with appropriate parameters can suppress the rotor system vibration amplitude. The conclusion can provide a reference for the design of textual parameters of semi-floating ring bearings. [ABSTRACT FROM AUTHOR]

In order to reduce the temperature in the marine engine cabin, improve the working environment of the staff and meet the economy and emission requirements, the cooling system of the engine was experimentally investigated in the present study. In this regard, water cooling and air-cooling schemes were studied and the main indicators including engine torque, smoke-emission, and exhaust temperature were analyzed. The obtained results indicate that the highest torque can be obtained from the air-cooling turbine case and air-cooling exhaust pipe. As the applied torque decreases, the outlet smoke first decreases then increases and decreases finally. Moreover, it is found that the water-cooling turbine case and water-cooling exhaust pipe increase the smoke. When the turbocharger is equipped with a water-cooling turbine case and water-cooling exhaust pipe, the higher the engine torque, the higher the turbine exhaust temperature and oil tank temperature, and the greater the reduction of the exhaust temperature. The engine torque is in direct proportion to the fuel consumption. The greater the torque, the higher the engine speed and the greater the fuel consumption. The engine torque is inversely proportional to the fuel consumption rate. The greater the torque, the smaller the fuel consumption rate. In cases with water cooling exhaust devices at 110% loading speed, the temperature after the intercooler is higher than that with the air-cooling exhaust device. After the intercooler, the pressure increases as the applied torque increases, and a higher-pressure ratio can be obtained from the air-cooling exhaust device. The higher the engine torque, the higher the temperature of the turbine exhaust, the higher the outlet temperature of the circulating cooling water, and the higher the temperature in the cabin. It was concluded that the exhaust device of the air-cooling turbine case and water-cooling exhaust pipe can reduce the temperature in the engine parts by up to 2℃, thereby improving the working environment of the cabin staff, economic performance, and the emission index.

Introduction. The diesel air supply system is designed to increase the air supply to the piston part of the engine, which increases its power. The system includes a supercharging unit (turbocharger) and an aftercooler. As their connection with the piston part is gas-air, this limits the range of feasible operation of the diesel engine. In recent years, the development of the air supply system, which is contributed to the improvement of the fuel efficiency of the diesel engine, is aimed at increasing the turbocharger efficiency and expanding its feasible operation range. The article proposes a new way of improving the fuel efficiency of diesel locomotives: control of two supercharging units (registered supercharging) by successively switching on each for diesel operation in each of the two power modes — below and above average power.Materials and methods. A diagram of the diesel engine air supply with a registered supercharging system is given, and a method for graph-analytical computation of the combined operation of supercharging units with the piston part of the engine is given.Results. The authors substantiated and selected ways of increasing the fuel efficiency of diesel locomotives in operation by improving the characteristics of the air supply system at modes below average power. The calculation and experimental method gave an estimate of the increase in the fuel efficiency of a 2TE25K diesel locomotive equipped with a diesel engine with a registered supercharging system, compared with a standard 21-26DG diesel generator.Discussion and conclusion. The practice of creating, researching and implementing registered supercharging systems at JSC Kolomensky Zavod and abroad shows that, despite the complexity of the design, such systems give a significant increase in the efficiency of the propulsion system in operation. It is recommended to check the characteristics of a diesel locomotive with the proposed registered air supply system on a bench diesel generator, followed by an operational check on a diesel locomotive.

The reliability of the engine largely depends on the technical condition of the fuel equipment. It is known that the efficiency of cars depends on the operating conditions that change during the seasons of the year. The aim of the study is to establish the influence of seasonal operating conditions on the parameter of the failure rate of elements of the power supply system of KAMAZ-43118 car engines. The article presents a fragment of the research results. To achieve this goal, the theoretical part considers the factors affecting the reliability of the system under study. From the analysis of sources, it was found that with the change of the season of the year, road and transport conditions, natural and climatic factors significantly affect the food system. In this regard, the hypothesis of the study is put forward: natural and climatic factors significantly affect the reliability of the power supply system of KAMAZ-43118 car engines. At the first stage of experimental studies, statistical data on the operating time for failure of the power supply system of KAMAZ-43118 cars were processed, the elements of the system with the greatest number of failures were identified. At the second stage, the influence of air temperature on the parameter of the failure flow of the elements of the power supply system of KAMAZ-43118 car engines was established. With the help of correlation analysis, the significance of seasonal changes in natural and climatic factors is proved. At the third stage, a methodology for using the obtained data to adjust the volume of spare parts and materials in the warehouse is proposed. The scientific novelty of the research is to establish the regularities of the influence of air temperature on the parameter of the failure flow of fuel equipment elements of KAMAZ-43118 vehicles. The practical significance lies in the possibility of using the results of the study in the development of a methodology for optimizing the volume of spare parts and materials in the warehouse. Further research will be aimed at improving the reliability of the power supply system taking into account seasonal operating conditions by adjusting the frequency of maintenance.

Understanding heat delivery in a multifaceted and vital engine component, such as the turbocharger, is important for improving engine performance and efficiency, but it is challenging to determine. In this paper, the temperature distribution in a turbocharger body was measured experimentally using a thermal camera, and a one-dimensional simulation of a turbocharger was developed for the temperature distribution. As part of the work, an innovative method is used to determine the thermal radiation constant of the turbocharger housing. In this method, the complete turbocharger system was first installed in a laboratory furnace and, at each stage, the temperature of the furnace was carefully adjusted. After temperature stabilization, a thermal image was taken with a thermal camera, and the radiation coefficient was obtained. Finally, a measurement of the temperature distribution was performed on the engine's test cell for the turbochargers of two three-cylinder gasoline engines (i.e. engines 1200 cc and 999 cc). The experiments include steady-state and transient tests. The transient tests include hot and cold tests at various operating conditions. The results showed that the maximum temperature of the turbine housing varies linearly with inlet gas temperature. Also, the axial distribution of the temperature in the compressor volute shows that temperature increases from the inlet side to the bearing housing side. Based on the numerical results, the maximum turbine housing temperature for engine 1200 cc is 679 °C and for engine 999 cc is 523 °C. [ABSTRACT FROM AUTHOR]

Obtaining the best operating parameters of the internal combustion engine has focused the attention of designers and researchers since the first years of its creation. Initial research focused on increasing engine power and overall efficiency. As time passed, these aspirations became more sophisticated and began to concern other operating parameters of the drive unit. The basic problem, however, remained the improvement of filling the cylinder with the working medium. Turbocharger charging consists in using the energy of the exhaust gases to drive a turbine placed on a common shaft with a compressor supplying air under increased pressure to the cylinders. Over time, the turbocharger became one of the key elements and its technical condition began to play a key role in the operation and performance of modern drive units. Like every element, the turbocharger itself is not without its faults. This procedure is known among manufacturers who, when designing power units and their assemblies, pay special attention to the essence of turbocharger construction. Since it is impossible to predict all the phenomena accompanying a working turbocharger at the design stage, the authors of this paper conducted bench tests of a selected batch of turbochargers, focusing mainly on the vibration measurements of the turbocharger rotating assembly. At the same time, we present a dynamic model of the mentioned system based on the analyses resulting from the solutions of the equations of a numerical model. In order to give the research a practical aspect, the results of the theoretical research were compared with the results of bench tests. It has been shown that the basic problem is to guarantee the correct operating parameters of the bearings in the position of static and dynamic equilibrium. Obtaining such operating parameters requires finding a compromise solution, e.g., between the maximum temperature in oil films and the amplitudes of vibration accelerations in bearing nodes. The research results presented in the article can be used as a field for further discussion in the field of research on the reliability of turbochargers and be helpful in the design process in order to avoid design errors and reduce production costs. [ABSTRACT FROM AUTHOR]

In order to reduce the temperature in the marine engine cabin, improve the working environment of the staff and meet the economy and emission requirements, the cooling system of the engine was experimentally investigated in the present study. In this regard, water cooling and air-cooling schemes were studied and the main indicators including engine torque, smoke-emission, and exhaust temperature were analyzed. The obtained results indicate that the highest torque can be obtained from the air-cooling turbine case and air-cooling exhaust pipe. As the applied torque decreases, the outlet smoke first decreases then increases and decreases finally. Moreover, it is found that the water-cooling turbine case and water-cooling exhaust pipe increase the smoke. When the turbocharger is equipped with a water-cooling turbine case and water-cooling exhaust pipe, the higher the engine torque, the higher the turbine exhaust temperature and oil tank temperature, and the greater the reduction of the exhaust temperature. The engine torque is in direct proportion to the fuel consumption. The greater the torque, the higher the engine speed and the greater the fuel consumption. The engine torque is inversely proportional to the fuel consumption rate. The greater the torque, the smaller the fuel consumption rate. In cases with water cooling exhaust devices at 110% loading speed, the temperature after the intercooler is higher than that with the air-cooling exhaust device. After the intercooler, the pressure increases as the applied torque increases, and a higher-pressure ratio can be obtained from the air-cooling exhaust device. The higher the engine torque, the higher the temperature of the turbine exhaust, the higher the outlet temperature of the circulating cooling water, and the higher the temperature in the cabin. It was concluded that the exhaust device of the air-cooling turbine case and water-cooling exhaust pipe can reduce the temperature in the engine parts by up to 2°C, thereby improving the working environment of the cabin staff, economic performance, and the emission index. [ABSTRACT FROM AUTHOR]

In recent years, various technologies have been developed for hybrid vehicles, ranging from energy management to the type of engines used, where Diesel engines have been used with the aim to improve fuel efficiency. This work presents a novel scheme for energy recovery from the exhaust gases of a turbocharged diesel engine integrated into a hybrid powertrain. The operation is explained through simulations conducted in MATLAB, using a fifth-order dynamic model where the dynamics of the compressor and turbine are not coupled and for which a feedback linearized controller is designed. Simulation results confirm the presence of excess energy in the exhaust gases. To demonstrate this, an engine velocity profile is simulated and the available o required power in both input and output manifolds is determined. The integral of the difference between these two powers clearly identifies an energy excess that can be converted to electric energy to be used in the propulsion system. This decoupling of the compressor and turbine is crucial as in conventional turbochargers they are mechanically coupled. The implementation of this schemes requires to couple to the shaft of the turbocompresor a high speed electrical engine that absorbs the available energy excess. Finally, the achieved recovery ranges from 1-3%, which demonstrates the effectiveness of the proposal.