Turbocharger Performance Research Articles

Investigation on the nonlinear behaviors of floating ring bearings based on nonlinear stiffness and damping coefficient models

Purpose The purpose of this study is to address the gaps in existing research on the nonlinear characteristics of floating ring bearings, particularly by focusing on second-order nonlinear stiffness and damping coefficients. Traditional analytical models have limitations in terms of accuracy and computational efficiency. This research aims to develop a more efficient and accurate method for analyzing these nonlinear characteristics, which are crucial for optimizing the design and performance of turbocharger floating ring bearings. The study also seeks to explore how variations in clearance ratio and load influence these coefficients. Design/methodology/approach This study develops a novel approach for analyzing the nonlinear characteristics of floating ring bearings by utilizing second-order nonlinear stiffness and damping coefficients. The proposed method replaces traditional analytical solution models with a nonlinear stiffness and damping coefficient model, enhancing both computational efficiency and accuracy. The model is validated through extensive simulations that account for varying clearance ratios and load conditions. The results are compared with those obtained from conventional methods, demonstrating the effectiveness of the proposed approach in accurately capturing the nonlinear behavior of turbocharger floating ring bearings. Findings The study finds that the proposed nonlinear stiffness and damping coefficient model significantly enhances computational efficiency while accurately representing the nonlinear characteristics of floating ring bearings. The model not only reduces computation time but also provides a more precise analysis compared to traditional methods. Moreover, the research reveals that the clearance ratio and load conditions of the floating ring bearings have a substantial impact on the nonlinear stiffness and damping coefficients. These findings suggest that the proposed model and method could be highly beneficial for advancing the design and research of floating ring bearings in turbochargers. Originality/value With this statement, the authors hereby certify that the manuscript “Investigation on the nonlinear behaviors of floating ring bearings based on nonlinear stiffness and damping coefficient models” submitted to the journal Industrial Lubrication and Tribology is the results of their own effort and ability. They hereby confirm that this manuscript is their original work and has not been published nor has it been submitted simultaneously elsewhere. They further confirm that they have checked the manuscript and have agreed to the submission. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-09-2024-0324/

Heat Transfer Enhancement in Pulsating Flows: A Bayesian Approach to Experimental Correlations

Abstract This research focuses on improving the modeling of heat transfer effects in pulsating exhaust flows. We address the challenges of understanding oscillating flow by employing the Metropolis–Hastings Markov Chain Monte Carlo sampling method for parameter estimation, accounting for measurement uncertainties. The knowledge can be applied to waste heat from reciprocating devices, pulsating turbocharger performance, and flow fields with significant cyclic variations. We demonstrate the feasibility of characterizing heat transfer capacity in pulsating flows using Bayesian inference and polynomial regression for experimental data correlation. This methodology is furthermore applied to identify heat transfer patterns in cold gas flow through a heated pipe across a range of mass flowrates and pulsating frequencies. To achieve this, the thermal performance variations across the length of the pipe through temperature and pressure changes are quantified. The model developed exhibits robust performance and high data efficiency (R2∈[0.83,0.89]) and notable extrapolation capacity in predicting mean heat transfer behavior based on boundary measurements. The results address the lack of experimental insights into pulsating flows encountered in heavy-duty transport applications and can be extended for heat recovery in systems such as exhaust manifolds and organic Rankine cycle gas turbines.

Heat Propagation Across Turbocharger Unit with Variable Turbine Inlet Temperature

Currently, issues about emission gains serious attention among the lawmakers and governments. Multiple regulation and enforcements have been applied to reduce the level of emission that released to the environment. Vehicle emissions have been identified as one of the major polluters thus forcing the carmakers to explore new technology to reduce the vehicle emissions. One of the technologies that have been preferred by the carmakers is the applications of forced induction system to the internal combustion engine. By using the forced induction system where currently turbocharger system is more often used compared to supercharger, two benefits can be achieved which are improvements of engine efficiency and engine size reduction. However, the ability of turbocharger unit to deliver compressed air can be affected by the amount of heat that travels along the turbocharger unit itself. In this paper, the effect of heat that originated from the exhaust gas that enters the turbine inlet towards the turbocharger performance was measured and analysed. An automotive turbocharger unit manufactured by Garrett Turbocharger model GT2056 was used in the study. The rotational speed is set between 20 000 rpm to 70 000 rpm and the temperature at turbine inlet is set between 40℃ to 100℃. The parameters that measured are the temperature difference at internal turbine, internal bearing temperature difference, internal compressor temperature difference, turbine casing temperature difference, bearing housing temperature difference and compressor housing temperature difference. From the results obtained, it can be observed that the heat travels from turbine towards the compressor side through the conduction between the contacting parts between the turbine casing, bearing housing and lastly at compressor casing. The heat that arrives at the compressor side through the casing will give small effect to the air mass flow that delivered by the compressor.

Parametric Investigation on the Influence of Turbocharger Performance Decay on the Performance and Emission Characteristics of a Marine Large Two-Stroke Dual Fuel Engine

Identifying and analyzing the engine performance and emission characteristics under the condition of performance decay is of significant reference value for fault diagnosis, condition-based maintenance, and health status monitoring. However, there is a lack of relevant research on the currently popular marine large two-stroke dual fuel (DF) engines. To fill the research gap, a detailed zero-/one-dimensional (0D/1D) model of a marine two-stroke DF engine employing the low-pressure gas concept is first established in GT-Power (Version 2020) and validated by comparing the simulation and measured results. Then, three typical types of turbocharger performance decays are defined including turbine efficiency decay, turbine nozzle ring area decay, and turbocharger shaft mechanical efficiency decay. Finally, the three types of decays are introduced to the engine simulation model and parametric runs are performed in both diesel and gas modes to identify and analyze their impacts on the performance and emission characteristics of the investigated marine DF engine. The results reveal that turbocharger performance decay has a significant impact on engine performance parameters, such as brake efficiency, engine speed, boost pressure, etc., as well as CO2 and NOx emissions, and the specified limit value on certain engine operational parameters will be exceeded when turbocharger performance decays to a certain extent. The changing trend of engine performance and emission parameters as turbocharger performance deteriorates are generally consistent in both operating modes but with significant differences in the extent and magnitude, mainly due to the distinct combustion process (Diesel cycle versus Otto cycle). Furthermore, considering the relative decline in brake efficiency, engine speed drop, and relative increase in CO2 emission, the investigated engine is less sensitive to the turbocharger performance decay in gas mode. The simulation results also imply that employing a variable geometry turbine (VGT) is capable of improving the brake efficiency of the investigated marine DF engine.

Experimental investigation of the matching boundary and optimization strategy of a variable geometry turbocharged direct-injected hydrogen engine

Experimental investigation of the matching boundary and optimization strategy of a variable geometry turbocharged direct-injected hydrogen engine

Fluid dynamic analysis and design strategies for a deswirler device for the direct measurement of radial turbine isentropic efficiency in experimental test rig

Fluid dynamic analysis and design strategies for a deswirler device for the direct measurement of radial turbine isentropic efficiency in experimental test rig

Towards eliminating friction and wear in plain bearings operating without lubrication

Plain bearings, renowned for their versatility and simplicity, are extensively utilized in engineering design across various industries involving moving parts. Lubrication is vital to the functioning of these bearings, yet their usage is inhibited under dynamic load conditions, or at elevated or reduced temperatures due to this dependency on lubrication. This study introduces an innovative method to significantly mitigate friction and wear in plain bearings operating without lubrication. The plain bearings were constructed from steel–bronze pairs, where the steel shafts were alloyed with bismuth oxide via short-pulse laser treatment. MnO2 was utilized as a carrier to incorporate the bismuth oxide into the surface layers of the steel. Insights from transmission electron microscopy and X-ray photoelectron spectroscopy revealed a highly non-equilibrium state of matter, unattainable through conventional engineering methods. The tribological performance of the modified steel disks was assessed via a block-on-ring sliding test, demonstrating superior wear and friction performance without lubrication, as well as an ultra-low coefficient of friction. Remarkably, the modified friction pairs remained functional after 200 km of linear sliding at a load of 250 N (12.5 MPa) and a sliding speed of 9 m/s. To substantiate the technique’s viability, we tested the performance of an internal combustion engine turbocharger fitted with a modified steel shaft. The turbocharger’s performance validated the long-term effectiveness of the steel–bronze coupling operating without lubrication at 75,000 rpm. The simplicity and resilience of this technique for modifying steel–bronze pairs offer a ground-breaking and promising approach for a wide range of applications.

Investigation of a Novel Turbine Housing to Produce a Nonuniform Spanwise Flow Field at the Inlet to a Mixed Flow Turbine and Provide Variable Geometry Capabilities

Abstract Automotive engine downsizing has placed an increased focus on the ability of the turbocharger to provide adequate boost levels across the full engine operating range. To achieve the desired levels of turbocharger performance, the turbine must be capable of operating effectively at the intended design point and also at off-design conditions. Mixed flow turbines (MFTs) provide a potential method to improve performance at off-design conditions and during transient engine operation. A unique feature of an MFT is the spanwise variation of incidence angle at the rotor leading edge. This results in additional flow separation from the blade suction surface near the hub under a wide range of operating conditions. The flow separation generates additional loss and has a detrimental impact on turbine performance. A novel design of a turbine volute similar to a conventional twin-entry turbine volute was examined. The novel turbine volutes were designed to produce a spanwise variation in flow conditions at the rotor inlet. The primary objective was to reduce the incidence angle and increase the mass flowrate at the hub side of the passage relative to the shroud side, as it has previously been identified that this can be beneficial for MFT performance. A number of different volute geometries were examined by numerical analysis to determine the impact of key parameters on turbine performance. The results indicated that generating a suitable spanwise flow distribution could produce a moderate improvement in turbine efficiency at off-design operating conditions. The novel volute design also provided a means of achieving a degree of variable geometry operation to further improve off-design performance. Turbine performance was examined under the variable geometry operation and an improvement in turbine power output at low-speed, off-design conditions was achieved. This was analogous to operating with a conventional pivoting vane variable geometry system and had the potential to benefit performance during transient engine operation.

Heat Generation Inside Turbocharger Without External Heat Source

Recently, many vehicle manufacturers started to invest in new technology to reduce the emission produced by their engines. Due to the emission regulations that become more stringent and the rising demand for highly efficient vehicles, many new technologies were introduced to achieve the demand. One of the technologies that gain popularity in modern vehicles is applying force induction systems such as turbocharging and supercharging the engine. By using the turbocharger, two major advantages can be achieved which are increasing engine efficiency and engine size reduction. However, turbocharger performance will be affected by the amount of heat that is generated due to friction inside the bearing, air compression process and also the heat transfer from the exhaust gas that has high temperature and pressure. In this paper, the heat generation inside the turbocharger unit without any external heat source was measured and analysed. A turbocharger unit from Garrett Turbocharger where the model is GT2056 was used for this experiment. The operating speed in the study is recorded between 20 000 rpm until 70 000 rpm and the temperature at the turbine inlet and compressor inlet is at room temperature. The parameters that were measured are the temperature difference at the turbine side, bearing housing and also compressor side. From the results obtained, it can be concluded that the bearing housing produces a higher amount of heat compared to the compressor side while the turbine side will experience heat loss.

Analysis of performance and time lag of turbocharger turbines fed with gasoline and diesel burnt gases and air under pulsating flow conditions

The turbine, an enabling component of turbochargers, is a seat of highly complex unsteady flow as well as varying gas compositions between diesel and gasoline engines. Thus, it is necessary to take into account different physical models when simulating such turbines. Researchers have often considered the turbine working gas as air, which may not lead to an accurate prediction of actual turbine characteristics. In the present work, the effect of the working gas on the performance of turbocharger turbines as well as on the turbo lag was investigated through a set of numerical simulations for six wastegate opening degrees from 0% up to 100% and under a wide range of the flow pulse frequency ranging from 33.33 up to 166.66 Hz. Four working fluids were involved in this study which are the gasoline burnt gas, diesel burnt gas, air with like gasoline engine waves, and air with like diesel engine waves. The performance of the turbine and its responsiveness quantified as the time lag with burnt gases from both diesel and gasoline engines were compared to those with air. Results showed totally deviated unsteady performance characteristics compared to the turbine working with air. Results also confirmed that considering the working fluid as air may not lead to a fair representation of the actual turbine performance characteristics. The findings of this work put emphasis on the importance of the gas composition when modeling such turbines by engineers especially during the design process where a good turbocharger-engine match has to be met.

TURBODYNA: A Generic One-Dimensional Dynamic Simulator for Radial Turbomachinery

AbstractThe turbocharged piston-driven engines are widely used in high altitude long endurance unmanned aerial vehicles (HALE UAVs). Repeated actions of engine pistons and valves give rise to engine pulsations resulting in intensive unsteady flows in the turbocharger. One-dimensional (1-D) modeling, which is computationally effective, plays a crucial role in evaluating turbocharger performance and conducting turbocharger-engine matching under pulsating conditions. The present work introduces a newly developed 1-D software (TURBODYNA) for the sake of improving traditional 1-D modeling's accuracy and generality. The advantages and capabilities of TURBODYNA are illustrated by applying it to three different and typical sorts of turbocharger applications: the single-entry turbine, the twin-entry turbine, and the centrifugal compressor. The unsteady testing conditions include high frequent pressure pulses for the single-entry turbine, out-of-phase pressure pulses for the twin-entry turbine, and rotating stall and surge for the centrifugal compressor. Results show that, by contrast to traditional 1-D modelings, the current 1-D modeling has achieved exceptional improvements in both accuracy and applicability. The novel and powerful tool provides a solid framework for assessing turbocharger unsteady performances and addressing turbocharger-engine matching.

Engine performance improvements through turbocharger matching and turbine design

AbstractIt is interesting to improve engine system performance with turbocharger technologies. In this study, a systematic simulation for engine and turbocharger matching to provide full utilization of the turbocharger potential and improve the engine performance without sacrificing the emission is developed. A velocity ratio concept was proposed to count the turbocharger performance impacts due to the diameter ratio of compressor and turbine wheels. A design of experiments was used to optimize the turbocharger and engine performance for different turbocharger factors. A better‐matched turbocharger was obtained. A multidisciplinary optimization method was used to design a mixed flow turbine wheel to reduce the turbine velocity ratio at peak efficiency and increase the overall turbocharger efficiency. Results showed that about 0.4% torque improvements and 1.2% reductions in the engine brake‐specific fuel consumption were obtained without making any other changes to the engine. This study demonstrated that systematic simulations for engine systems and considering turbocharger wheel diameter ratio effects could further improve the turbocharged engine system matching and the engine performance.

An evaluation method for transient response performance of a turbocharger in gasoline engine: Simulation and experiment

The vital issue of response lag and soot emission during transient operation of turbocharged engine, has been studied so far mainly on experiment in engine system rather than turbocharger basis. The study of turbocharger transient performance, however, is extremely important to manufacturers due to the stringent regulations of exhaust emission and economy for the turbocharger engine. Therefore, a general method independent of the engine for evaluating the transient response performance of a gasoline turbocharger is proposed in this paper. First, an explicit relationship between key thermodynamic parameters of turbine and compressor and the evaluation index of [Formula: see text] that can characterize turbocharger transient response are established. Secondly, the proposed evaluation method is tested and verified using the coupling between GT-Power and MATLAB Simulink software based on the gasoline turbocharger. The simulation results show that the appropriate conditions should be selected for the transient response test, including the starting and ending speed, the starting mass flow rate, etc. For this proposed turbocharger, the value of [Formula: see text] has a good consistency when the ending speed is 200,000 r/min and the initial mass flow rate is in the range of 0.0715∼0.0756 kg/s. Moreover, the influence of rotor moment of inertia, turbine efficiency and compressor efficiency on [Formula: see text] is analyzed in this selected condition. Finally, the evaluating method of the transient response performance of the turbocharger is conducted on a test bench. The test results are in good agreement with the simulation results, indicating that the proposed evaluation method for transient response of turbocharger has a good predictability and can be used for quantitative evaluation of transient response-ability for different turbochargers independent of engine.

An Optimization-Based Design Strategy for Centrifugal Compressors of Automotive Turbochargers and the Comparison of Five Particular Optimization Methods

Abstract It is possible to optimize a turbocharger's performance for a broad range of engine operating points. However, most of the turbochargers have distinctive performance characteristics independent of engine operation. Therefore, the correct way to obtain the maximum performance from an engine is to design its turbocharger with the specific engine performance map in mind. This paper deals with the effective use of computational methods to create optimal turbocharger compressors for realistic engine operating conditions. The present process has four steps: preliminary analysis, throughflow analysis, optimization, and computational fluid dynamics (CFD) analysis. In the preliminary analysis, gas dynamics and Euler turbomachinery equations are used to calculate the basic dimensions. In the throughflow analysis, calculated dimensions are used to create a parametric three-dimensional (3D) geometry. A throughflow analysis generates the two-dimensional flow results using the meridional geometry of this 3D geometry. The main contribution of this research is the five different optimization methods that are employed and compared. The efficiency of the rotor is defined as the objective function to be maximized. A comparison of the five optimization schemes showed that the genetic algorithm (GA) is the most suitable method for the current design optimization problem. In the final step, a CFD solver is used to assess the created design's final performance. The CFD results' validity is checked against a reference compressor's test results. This study also indicates that preliminary sizing followed by a well-built throughflow analysis eliminates the need for a fully parametric 3D CFD-based design.

Effect of adding ceramic thermal barrier coating on the turbocharger efficiency, external and internal heat transfer

Abstract Turbocharger is a device installed on an internal combustion engine to boost its thermal efficiency. A turbocharger consists of three main components, namely the turbine, central housing, and compressor. The common material for commercial turbine housing is cast iron, for its lower cost yet resilience at elevated temperature. Given the high exhaust temperature a turbocharger is exposed to, energy loss in the form of heat transfer is inevitable. It is known to H turbine efficiency by up to 30%. This research aims to determine the turbocharger efficiency in the presence of thermal barrier coating (TBC) on the inner surface of turbine volute. Particularly, this work will focus on the internal and external heat transfer of the turbine and its impact on efficiency. The subject turbocharger is a commercial single-scroll vaneless unit commonly used in gasoline passenger vehicle. Yttria-Stabilized Zirconia (YSZ) is chosen as the TBC material, due to high melting point (around 2700°C), good thermal insulation property and very low thermal expansion compared to other ceramic materials. The YSZ was applied to the inner surface of turbine volute via plasma coating technique. However, due to the large disparity in thermal expansion between YSZ and cast iron, the TBC is prone to cracking at elevated exhaust temperature. Thus, an Inconel 718 turbine housing, with closer thermal expansion to YSZ, was refabricated for the use of this study The turbocharger performance was experimentally measured on the LoCARtic turbocharger gas stand. The turbine inlet temperature (TIT) was varied at 150, 350, 550, 650 and 750°C, while the compressor operating condition was maintained throughout the testing for equivalent comparison. From the result, the turbocharger efficiency drops when TIT is increased, and the turbine pressure ratio becomes lower. Overall, the external heat transfer loss is found to reduce 7% to 40% and no significant difference noticed on the internal heat transfer.

Analysis on capability of power recovery of marine diesel engine at high backpressure conditions

Marine diesel engines can be exposed to high backpressure conditions in the scenario of maritime, because the outlet of its exhaust manifold is normally below the sea surface to reduce the emission level. The performance of the engine has been confirmed to drastically deteriorate due to the high exhaust backpressure. The current methods for turbo-engine matching and power recovery at high backpressure conditions are specific instead of general. This article aims to understand the mechanism of influence on turbocharged engine performance by exhaust backpressure, and to develop a performance evaluation method as well as optimized methods of turbo-engine matching at high backpressure conditions. Firstly, numerical method is established for a 16-cylinder V-type turbocharged diesel engine and calibrated/validated based on experimental results. The influence of the backpressure on engine and turbocharger performance is discussed by the numerical method. The power recovery efforts are founded to be constrained by the maximum cylinder pressure and exhaust temperature. The influence of the effective flow area of the turbine and turbocharger efficiency on the operational constraints are discussed. It is concluded that the influence on intake air mass flow and fuel margin is the source of the influence on the constraints. Based on the findings, a capability region of engine power recovery is proposed, which is bounded by curves of maximum cylinder pressure and maximum exhaust temperature, respectively. Furthermore, the availability of exhaust gas is the root of influencing the boundaries of the region. According to the mechanism, a universal evaluation method based on the available energy of the exhaust gas is proposed which is tailored for turbo-engine matching at different exhaust backpressures.

Experimental Energy and Exergy Analysis of an Automotive Turbocharger Using a Novel Power-Based Approach

The performance of turbochargers is heavily influenced by heat transfer. Conventional investigations are commonly performed under adiabatic assumptions and are based on the first law of thermodynamics, which is insufficient for perceiving the aerothermodynamic performance of turbochargers. This study aims to experimentally investigate the non-adiabatic performance of an automotive turbocharger turbine through energy and exergy analysis, considering heat transfer impacts. It is achieved based on experimental measurements and by implementing a novel innovative power-based approach to extract the amount of heat transfer. The turbocharger is measured on a hot gas test bench in both diabatic and adiabatic conditions. Consequently, by carrying out energy and exergy balances, the amount of lost available work due to heat transfer and internal irreversibilities within the turbine is quantified. The study allows researchers to achieve a deep understanding of the impacts of heat transfer on the aerothermodynamic performance of turbochargers, considering both the first and second laws of thermodynamics.

РЕЗУЛЬТАТЫ ИССЛЕДОВАНИЯ ВЛИЯНИЯ УСЛОВИЙ ФУНКЦИОНИРОВАНИЯ ТУРБОКОМПРЕССОРА НА ЕГО РАБОТОСПОСОБНОСТЬ

The operability of the bearing assembly, which ensures the operation of the turbocharger at different speeds of its rotor, determines the reliability of the turbocharger as a whole. In this regard, the condition of the turbocharger bearing assembly determines the performance of the entire turbocharger. The purpose of the research is to justify the parameter that determines the performance of the turbocharger and a comparative assessment of changes in the state of turbochargers with a standard lubrication system and when using individual bearing assembly lubrication systems. The main factors affecting the state of the turbocharger bearing assembly, and hence the length of the rotor rotation by inertia after the engine stops, are considered to be: the increase in the clearance in the bearing assembly, the speed of rotation of the turbocharger rotor before the engine stops, and the time of pressure drop in the bearing assembly to zero after the engine stops. To obtain dependences describing the effect of the gap in the turbocharger bearing, the time of pressure drop in its lubrication system after the engine stops, and the change in the duration of rotation of the turbocharger rotor by inertia in dynamics, we conducted experimental studies. The experiment involved vehicles with a standard lubrication system and with an individual lubrication system for the turbocharger bearing assembly. The data was sample along the main diagonal of the matrix of experimental indicators. The dependences of the effect of the gap and the time of pressure drop in the bearing assembly on the duration of rotation of the rotor of the turbocharger by inertia after stopping the engine, at the speed of rotation of the rotor before stopping the engine 10000, 25000 and 40000 min-1 are obtained. A comparative analysis of this indicator is given for turbochargers with a standard and individual lubrication system of the bearing assembly, which shows that the duration of rotation of the rotor by inertia increases from 45 s (standard lubrication mode) to 90 s (with an individual lubrication system). This gives us reason to believe that the wear rate of the bearing will decrease by half during operation

On the integration of physics-based and data-driven models for the prediction of gas exchange processes on a modern diesel engine

The need for precise control of complex air handling systems on modern engines has driven research into model-based methods. While model-based control can provide improved performance over prior map-based methods, they require the creation of an accurate model. Physics-based models can be precise, but can also be computationally expensive and require extensive calibration. To address this limitation, this work explores the integration of data-driven models into an overall physics-based framework and applies this approach to the gas exchange processes of a diesel engine with a variable geometry turbocharger and exhaust gas recirculation. One of the most complex parts of this gas exchange loop is the turbocharger. Data-driven methods are used to capture the turbocharger performance and are also applied to the intake manifold, while the simpler features are captured with more traditional physics-based models. This combined modeling approach is able to capture the temperature and pressure dynamics with varying error levels depending on measurement availability and the inter-dependency of the submodels, with the turbocharger neural network model achieving a Normalized Mean Square Error (NMSE) of 5e-5 and the overall engine model achieving a NMSE of 4.5e-3. The work illustrates that the integration of data-driven models can improve overall model accuracy and may be able to reduce the number of sensors needed on the system. The contributions of this work are the development and demonstration of a neural network based turbocharger model and intake air path model, the development of empirical equation-based models for the rest of the engine components along the air path and the demonstration of the integration and interaction of these two types of model to adequately characterize engine operation for control applications.

Structural Strength and Reliability Analysis of Important Parts of Marine Diesel Engine Turbocharger

Supercharging is the main method to improve the output power of marine diesel engines. Nowadays, most marine diesel engines use turbocharging technology, which increases the air pressure and density into the cylinder and the amount of fuel injected correspondingly so as to achieve the purpose of improving the power. In a marine diesel engine, the turbocharger has become an indispensable part. The performance of turbochargers in a harsh working environment of high temperature and high pressure for a long time will directly affect the performance of diesel engine. Based on the market feedback data from manufacturers, the failure modes of compressor impeller, turbine blade, and turbine disk of marine diesel turbocharger are analyzed, and the statistical model of random factors is established. Using DOE design, the structural strength simulation data of 46 compressors and 62 turbines are obtained, and the response surface model is constructed. On this basis, Monte Carlo sampling is carried out to analyze the reliability of the compressor and turbine. The reliability of the compressor is good, while that of the turbine disk is 0.943 and that of the turbine blade is 0.96, which still has the potential of reliability optimization space. Therefore, a multiobjective optimization method based on the NSGA-II genetic algorithm is proposed to obtain the multiobjective optimization scheme data with the reliability and processing cost of turbine disk and blade as the objective function. After optimization, the reliability of turbine disk and blade is 1, the stress value of turbine blade is optimized by 4.7941%, the stress value of turbine disk is optimized by 3.0136%, the machining cost of the turbine blade is reduced by 15.5087%, and the machining cost of turbine disk is reduced by 3.9907%. At the same time, it is verified by simulation, the data based on NSGA-II multiobjective genetic algorithm are more accurate and have practical engineering reference value. The optimized data based on NSGA-II multiobjective genetic algorithm are used to manufacture new turbine samples, and the accelerated test of simulation samples is carried out. The cycle life of the optimized turbine can reach 101,697 cycles and 118,687 cycles, which is 51.75% and 77.11% longer than that of the unoptimized turbine. It can be seen that the optimized turbine can meet the requirements of the reliability index while reducing the manufacturing cost.