Intake Boosting

Baines, N. C.

doi:10.1002/9781118354179.auto126

Cited by 6 publications

(4 citation statements)

References 3 publications

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“…Since the turbine exhaust gas temperature measurement gives unrealistic results, due to the flow field characteristics at the radial turbine outlet, the average power was calculated on the basis of compressor power absorption, taking into account mechanical losses in the turbocharger bearings, estimated by the heat flux to the lubricating oil flowing through the turbocharger. 3…”

Section: Evaluating the Unsteadiness In Flow Systemsmentioning

confidence: 99%

“…To achieve this target, the full integration of different technologies such as downsizing, turbocharging, gasoline direct injection (GDI), variable valve actuation (VVA) and after-treatment systems must be accomplished. 2–4 As regards turbocharging, the optimization of turbochargers is an essential step, requiring a better knowledge of turbine and compressor performance over an extended range. The availability of experimental information on turbocharger behavior can help to enhance numerical simulation models, extremely useful to guide the choice of the turbocharging system for a specific engine.…”

Section: Introductionmentioning

confidence: 99%

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A detailed one-dimensional model to predict the unsteady behavior of turbocharger turbines for internal combustion engine applications

Piscaglia

Onorati

Marelli

et al. 2018

International Journal of Engine Research

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This article describes an investigation of the unsteady behavior of turbocharger turbines by one-dimensional modeling and experimental analysis. A one-dimensional model has been developed to predict the performance of a vaneless radial-inflow turbine submitted to unsteady flow conditions. Different from other approaches proposed in the literature, the turbine has been simulated by separating the effects of casing and rotor on the unsteady flow and by modeling the multiple rotor entries from the volute. This is a simple and effective way to represent the turbine volute by a network of one-dimensional pipes, in order to capture the mass storage effect due to the system volume, as well as the circumferential variation of fluid dynamic conditions along the volute, responsible for variable admittance of mass into the rotor through blade passages. The method developed is described, and the accuracy of the one-dimensional model is shown by comparing predicted results with measured data, achieved on a test rig dedicated to the investigation of automotive turbochargers. The validation of the code is presented and an analysis of the flow unsteadiness, based on a variety of parameters, is proposed.

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Section: Evaluating the Unsteadiness In Flow Systemsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A detailed one-dimensional model to predict the unsteady behavior of turbocharger turbines for internal combustion engine applications

Piscaglia

Onorati

Marelli

et al. 2018

International Journal of Engine Research

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“…Turbocharging technique, along with downsizing, Variable Valve Actuation systems, and Gasoline Direct Injection are today considered an effective way to reduce CO2 emissions in automotive gasoline engines, especially for the European and US markets [1,2,3]. The successful application of exhaust turbocharging to downsized engines must overcome various difficulties, related both to the specific operating environment (exhaust gas temperature level) and to engine performance, focusing on low-end torque and transient response.…”

Section: Introductionmentioning

confidence: 99%

Direct Evaluation of Turbine Isentropic Efficiency in Turbochargers: CFD Assisted Design of an Innovative Measuring Technique

Marelli¹,

Usai²,

Capobianco³

et al. 2019

SAE Technical Paper Series

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Turbocharging is playing today a fundamental role not only to improve automotive engine performance, but also to reduce fuel consumption and exhaust emissions for both Spark Ignition and Diesel engines. Dedicated experimental investigations on turbochargers are therefore necessary to assess a better understanding of its performance. The availability of experimental information on turbocharger steady flow performance is an essential requirement to optimize the engine-turbocharger matching, which is usually achieved by means of simulation models. This aspect is even more important when referred to the turbine efficiency, since its swallowing capacity can be accurately evaluated through the measurement of mass flow rate, inlet temperature and pressure ratio across the machine. However, in the case of a turbocharger radial inflow turbine, isentropic efficiency, directly evaluated starting from measurement of thermodynamic parameters at the inlet and outlet sections, can give significant errors. This inaccuracy is mainly related to the difficulty of a correct evaluation of the turbine outlet temperature due to the non-uniform distribution of flow field and temperature at the measuring section. This work is the follow up of a previous publication where an intensive measurement campaign was performed to obtain a reliable measurement of the turbine outlet temperature. To this aim, a handmade 3-hole probe (unlike most of the measuring probes available on the market, which are considered as intrusive) was adopted to perform measurement of the flow field, pressure and temperature downstream the turbine with special reference to different radial and tangential positions in two sections located near and far from the outlet machine, allowing the evaluation of the efficiency through local enthalpy fluxes across the turbine in cold and hot conditions upstream the turbine. The comparison between results obtained through the local measurements and those achieved through a direct measurement of turbine outlet temperature by three probes inserted in pipe with a different protrusion, have highlighted that heat transfer effects across the pipes and across the turbocharger components play an important role on the estimation of temperature profile at the outlet section. In order to put some light on this aspect, CFD simulations have been performed to estimate the impact of the heat transfer and flow distribution on the estimation of the isentropic efficiency. The OpenFOAM ® code has been adopted to simulate the actual turbine geometry resorting to multi reference frame (MRF) strategies, instead of mesh motion strategies, to characterize the flow pattern downstream of the turbine. Moreover, CFD analysis was used to design a specific device, whose goal was the dissipation of flow structures dominated by vorticity, achieving in this way a uniform distribution of the flow and temperature fields at the measuring section. This will result in a much more reliable evaluation of the turbine efficiency

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“…However, the coupling between the ICE and the turbocharger presents several difficulties [17]. The problem is inherent to the way in which each machine works.…”

Section: Motivationsmentioning

confidence: 99%

Synthesis of the 1D modelling of turbochargers and its effects on engine performance prediction

Dombrovsky¹

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Low fuel consumption is one of the main requirement for current internal combustion engines for passenger car applications. One of the most used strategies to achieve this goal is to use downsized engines (smaller engines while maintaining power) what implies the usage of turbochargers. The coupling between both machines (the turbocharger and the internal combustion engines) presents many difficulties due to the different nature between turbomachines and reciprocating machines. These difficulties make the optimal design of the turbocharged internal combustion engines a complicated issue.In these thesis a strong effort has been made to improve the global understanding of different physical phenomena occurring in turbochargers and in turbocharged engines. The work has been focused on the 1D modelling of the phenomena since 1D tools currently play a major role in the engine design process. Both experimental and modelling efforts have been made to understand the heat transfer and gas flow processes in turbochargers. Previously to the experimental analysis a literature review has been made in which the state of the art of heat transfer and gas flow modelling in turbochargers have been analysed.The experimental effort of the thesis has been focused on measuring different turbochargers in the gas stand and the engine test bench. In the first case, the gas stand, a more controlled environment, has been used to perform tests at different conditions. Hot tests with insulated and not insulated turbocharger have been made to characterise the external heat transfer. Moreover, adiabatic tests have been made to compare the effect of the heat transfer on different turbocharger variables and for the validation of the turbine gas flow models. In the engine test bench full and partial load tests have been made for model validation purposes.For the models development task, the work has been divided in heat flow models and gas flow models. In the first case, a general heat transfer model for turbochargers has been proposed based on the measured turbochargers and data available from previous works of the literature. This model includes a procedure of conductive conductances estimation, internal and external convection correlations and radiation estimation procedure. In the case of the gas flow modelling, an extended model for VGT performance maps extrapolation for both the efficiency and the mass flow has been developed as well as a model for discharge coefficient prediction in valves for two stage turbochargers.Finally, the models have been fully validated coupling them with a 1D modelling software simulating both the gas stand and the whole engine. On the one hand, the results of the validation show that compressor and turbine outlet temperature prediction is highly improved using the developed models. This results prove that the turbocharger heat transfer phenomena are important not only for partial load and transient simulation but also in full loads. On the other hand, the VGT extrapolation model accuracy is high even at...

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Intake Boosting

Cited by 6 publications

References 3 publications

A detailed one-dimensional model to predict the unsteady behavior of turbocharger turbines for internal combustion engine applications

A detailed one-dimensional model to predict the unsteady behavior of turbocharger turbines for internal combustion engine applications

Direct Evaluation of Turbine Isentropic Efficiency in Turbochargers: CFD Assisted Design of an Innovative Measuring Technique

Synthesis of the 1D modelling of turbochargers and its effects on engine performance prediction

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