Turbocharger matching methodology for improved exhaust energy recovery

Pesiridis, Apostolos; Salim, W. S-I. W; Martinez-Botas, Ricardo

doi:10.1533/9780857096135.4a.203

Cited by 20 publications

(12 citation statements)

References 14 publications

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“…The solid blue lines show the data fitted extrapolation, and the red line gives the unsteady turbine operation during engine cycle. The figure illustrates that usually the limited measured data has to be extrapolated far beyond the available range and underlines the importance of accurate extrapolation techniques, what is consistent with findings in [20,21]. Thus, the correct prediction of engine steady operation, as well as unsteady operation or even vehicle acceleration behavior, is strongly depending on sensible and correct extrapolation.…”

Section: Turbine Performance Under Pulsating Flow Conditionssupporting

confidence: 80%

On Mixed Flow Turbines for Automotive Turbocharger Applications

Lüddecke¹,

Filsinger²,

Ehrhard³

2012

International Journal of Rotating Machinery

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Due to increased demands for improved fuel economy of passenger cars, low-end and part-load performance is of key importance for the design of automotive turbocharger turbines. In an automotive drive cycle, a turbine which can extract more energy at high pressure ratios and lower rotational speeds is desirable. In the literature it is typically found that radial turbines provide peak efficiency at speed ratios of 0.7, but at high pressure ratios and low rotational speeds the blade speed ratio will be low and the rotor will experience high values of positive incidence at the inlet. Based on fundamental considerations, it is shown that mixed flow turbines offer substantial advantages for such applications. Moreover, to prove these considerations an experimental assessment of mixed flow turbine efficiency and optimal blade speed ratio is presented. This has been achieved using a new semi-unsteady measurement approach. Finally, evidence of the benefits of mixed flow turbine behaviour in engine operation is given. Regarding turbocharged engine simulation, the benefit of wide-ranging turbine map measurement data as well as the need for reasonable turbine map extrapolation is illustrated.

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Section: Turbine Performance Under Pulsating Flow Conditionssupporting

confidence: 80%

On Mixed Flow Turbines for Automotive Turbocharger Applications

Lüddecke¹,

Filsinger²,

Ehrhard³

2012

International Journal of Rotating Machinery

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“…This case is applicable for an automotive engine. Emission reduction technologies, such as exhaust gas recirculation and diesel particulate filters, render compressor and turbine matching as problematic [49] Several authors [17,42,48,50,51] indicated a fundamental agreement when matching a turbocharger and an engine, that is, torque at low speed and power at high engine speed. A large turbocharger provides power at high speed but experiences low-speed performance and transient response because of the lack of exhaust gas flow rate to overcome the inertia of the system.…”

Section: Turbochargingmentioning

confidence: 99%

Electric Boosting and Energy Recovery Systems for Engine Downsizing

Alshammari

Pesyridis

2019

Energies

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Due to the increasing demand for better fuel economy and increasingly stringent emissions regulations, engine manufacturers have paid attention towards engine downsizing as the most suitable technology to meet these requirements. This study sheds light on the technology currently available or under development that enables engine downsizing in passenger cars. Pros and cons, and any recently published literature of these systems, will be considered. The study clearly shows that no certain boosting method is superior. Selection of the best boosting method depends largely on the application and complexity of the system.

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“…The creation of steady state maps also typically relies on a narrow range of test data supplemented by data extrapolation techniques. These extrapolation methods can lead to performance prediction deviations of up to 10% at low blade speed ratios [5].…”

Section: Draftmentioning

confidence: 99%

A One-Dimensional Gas Dynamics Code for Turbocharger Turbine Pulsating Flow Performance Modelling

Feneley

Pesiridis

Chen³

2017

Volume 8: Microturbines, Turbochargers and Small Turbomachines; Steam Turbines

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As governments around the world ramp up their efforts to reduce CO2 emissions, downsizing internal combustion engines has become a dominant trend in the automotive industry. Air charging systems are being utilised to increase power density and therefore lower emissions by downsizing internal combustion engines. Turbocharging represents the majority of these air charging systems, which are commonly adopted for commercial and passenger vehicles. The process of matching turbomachinery to an engine during early-stage development is important to achieving maximum engine performance in terms of power output and the reduction of emissions. Despite on-engine conditions providing highly unsteady gas flows, current turbocharger development commonly uses performance maps that are produced from steady state measurements. There are other significant sources of error to be found in early stage turbocharger performance prediction, such as the omission of heat transfer effects, and the use of data extrapolation methods to cover the entire operating range of a device from limited data sets. Realistic engine conditions provide a complex heat transfer scenario, which is dependent upon load history and the component layout of the engine bay. Heat transfer effects are particularly prevalent at low engine loads, whilst pulsating effects are significant at both high and low engine speeds (and therefore exhaust pulse frequency). Compressor maps are often provided by manufacturers with a level of heat transfer corresponding to a gas stand test, not realistic engine conditions. This causes a mismatch when using the aforementioned maps in commercial engine codes. This reduces the quality of overall engine performance predictions, since as the temperature of the exhaust gas on the turbine side rises, the performance prediction increasingly deviates from the usual adiabatic assumption used in simulations. In the present work, a one-dimensional unsteady flow model has been developed to predict the performance of a vaneless turbine under pulsating inlet conditions, with scope to account for heat transfer effects. Flow within the volute is considered to be one-dimensional and unsteady, with mass addition and withdrawal used to simulate the gas flow between the volute and rotor. Rotor passages are also treated as one-dimensional and unsteady, with the equations being solved by the method of characteristics. This model is able to simulate the circumferential feeding of the rotor from the casing, unlike many previous zero and one-dimensional models. Building upon previous work, the basis of this code has been constructed in C++ with future integration with other modern gas dynamics codes in mind. By providing the appropriate instantaneous operating conditions at specified time intervals, a code such as this could theoretically negate the need for maps produced by steady-state data.

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Turbocharger matching methodology for improved exhaust energy recovery

Cited by 20 publications

References 14 publications

On Mixed Flow Turbines for Automotive Turbocharger Applications

On Mixed Flow Turbines for Automotive Turbocharger Applications

Electric Boosting and Energy Recovery Systems for Engine Downsizing

A One-Dimensional Gas Dynamics Code for Turbocharger Turbine Pulsating Flow Performance Modelling

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