IHI Charging Systems International

Heidelberg, Germany

IHI Charging Systems International

Heidelberg, Germany
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Walkingshaw J.,IHI Charging Systems International | Iosifidis G.,IHI Charging Systems International | Scheuermann T.,IHI Charging Systems International | Filsinger D.,IHI Charging Systems International | Ikeya N.,IHI Corporation
Proceedings of the ASME Turbo Expo | Year: 2015

As a means of meeting ever increasing emissions and fuel economy demands car manufacturers are using aggressive engine downsizing. To maintain the power output of the engine turbocharging is typically used. Due to the miss-match of the mass flow characteristics of the engine to the turbocharger, at low engine mass flow rates, the turbocharger can suffer from slow response known as "Turbolag". Mono-scroll turbines are capable of providing good performance at high mass flow rates and in conjunction with low inertia mixed flow turbines can offer some benefits for transient engine response. With a multientry system the individual volute sizing can be matched to the single mass flow pulse from the engine cylinders. The exhaust pulse energy can be better utilised by the turbocharger turbine improving turbocharger response, while the interaction of the engine exhaust pulses can be better avoided, improving the scavenging of the engine. The behaviour of a mono-scroll turbocharger with the engine using engine simulation tools has been well established. What requires further investigation is the comparison with multientry turbines. CFD (Computational Fluid Dynamics) has been used to examine the single admission behaviour of a twin and double scroll turbine. Turbocharger gas stand maps of the multi-entry turbines have been measured at full and single admission. This data has been used in a 0D engine model. In addition, the turbine stage has been tested on the engine and a validation of the engine model against the engine test data is presented. Using the validated engine model a comparison has been made to understand the differences in the sizing requirements of the turbine and the interaction of the monoscroll and multi-entry turbines with the engine. The impact of the different efficiency and mass flow rate trends of the mono and multi-entry turbochargers are discussed and the trade-offs between the design configurations regarding on engine behaviour are investigated. Copyright © 2015 by ASME.


Walkingshaw J.,IHI Charging Systems International | Iosifidis G.,IHI Charging Systems International | Scheuermann T.,IHI Charging Systems International | Filsinger D.,IHI Charging Systems International | Ikeya N.,IHI Corporation
Journal of Engineering for Gas Turbines and Power | Year: 2016

As a means of meeting ever increasing emissions and fuel economy demands, car manufacturers are using aggressive engine downsizing. To maintain the power output of the engine, turbocharging is typically used. Due to the mismatch of the mass flow characteristics of the engine to the turbocharger, at low engine mass flow rates (MFRs), the turbocharger can suffer from slow response known as âœTurbolag.â Mono-scroll turbines are capable of providing good performance at high MFRs and in conjunction with low inertia mixed flow turbines can offer some benefits for transient engine response. With a multi-entry system, the individual volute sizing can be matched to the single mass flow pulse from the engine cylinders. The exhaust pulse energy can be better utilized by the turbocharger turbine improving turbocharger response, while the interaction of the engine exhaust pulses can be better avoided, improving the scavenging of the engine. The behavior of a mono-scroll turbocharger with the engine using engine simulation tools has been well established. What requires further investigation is the comparison with multi-entry turbines. Computational fluid dynamics (CFD) has been used to examine the single-admission behavior of a twin-and double-scroll turbine. Turbocharger gas stand maps of the multi-entry turbines have been measured at full and single admissions. This data have been used in a 0D engine model. In addition, the turbine stage has been tested on the engine, and a validation of the engine model against the engine test data is presented. Using the validated engine model, a comparison has been made to understand the differences in the sizing requirements of the turbine and the interaction of the mono-scroll and multi-entry turbines with the engine. The impact of the different efficiency and MFR trends of the mono and multi-entry turbochargers is discussed, and the tradeoffs between the design configurations regarding on-engine behavior are investigated. © 2016 by ASME.


Walkingshaw J.,Queen's University of Belfast | Spence S.,Queen's University of Belfast | Jan E.,IHI Charging Systems International | Thornhill D.,Queen's University of Belfast
Proceedings of the ASME Turbo Expo | Year: 2010

Conventionally, radial turbines have almost exclusively used radially fibred blades. While issues of mechanical integrity are paramount, there may be opportunities for improving turbine efficiency through a 3D blade design without exceeding mechanical limits. Off-design performance and understanding of the secondary flow structures now plays a vital role in the design decisions made for automotive turbocharger turbines. Of particular interest is extracting more energy at high pressure ratios and lower rotational speeds. Operating in this region means the rotor will experience high values of positive incidence at the inlet. A CFD analysis has been carried out on a scaled automotive turbine utilizing a swing vane stator system. To date no open literature exists on the flow structures present in a standard VGT system. Investigations were carried out on a 90 mm diameter rotor with the stator vane at the maximum, minimum and 25% mass flow rate positions. In addition stator vane endwall clearance existed at the hub side. From investigation of the internal flow fields of the baseline rotor, a number of areas that could be optimized in the future with three dimensional blading were identified. The blade loading and tip leakage flow near inlet play a significant role in the flow development further downstream at all stator vane positions. It was found that tip leakage flow and flow separation at offdesign conditions could be reduced by employing back swept blading and redistributing the blade loading. This could potentially reduce the extent of the secondary flow structures found in the present study. © 2010 by ASME.


Harley P.,IHI Charging Systems International | Spence S.,IHI Charging Systems International | Filsinger D.,Queen's University of Belfast | Dietrich M.,Queen's University of Belfast | Early J.,IHI Charging Systems International
Proceedings of the ASME Turbo Expo | Year: 2015

After the development of a new single-zone meanline modelling technique, benchmarking of the technique and the modelling methods used during its development are presented. The new meanline model had been developed using the results of three automotive turbocharger centrifugal compressors, and single passage CFD models based on their geometry. The target of the current study was to test the new meanline modelling method on two new centrifugal compressor stages, again from the automotive turbocharger variety. Furthermore the single passage CFD modelling method used in the previous study would be again employed here and also benchmarked. The benchmarking was twofold; firstly test the overall performance prediction accuracy of the single-zone meanline model. Secondly, test the detailed performance estimation of the CFD model using detailed interstage static pressure tappings. The final component of this study exposed the weaknesses in the current modelling methods used (explicitly during this study). The non-axisymmetric flow field at the leading and trailing edges for the two compressors was measured and is presented here for the complete compressor map, highlighting the distortion relative to the tongue. Copyright © 2015 by ASME.


Walkingshaw J.,Queen's University of Belfast | Spence S.,Queen's University of Belfast | Ehrhard J.,IHI Charging Systems International | Thornhill D.,Queen's University of Belfast
Proceedings of the ASME Turbo Expo | Year: 2011

Off-design performance now plays a vital role in the design decisions made for automotive turbocharger turbines. Of particular interest is extracting more energy at high pressure ratios and lower rotational speeds. In this region of operation the U/C value will be low and the rotor will experience high values of positive incidence at the inlet. The positive incidence causes flow to separate on the suction surface and produces high blade loading at inlet, which drives tip leakage. A CFD analysis has been carried out on a number of automotive turbines utilizing non-radial fibred blading. To help improve secondary flows yet meet stress requirements a number of designs have been investigated. The inlet blade angle has been modified in a number of ways. Firstly, the blading has been adjusted as to provide a constant back swept angle in the span wise direction. Using the results of the constant back swept blading studies, the back swept blade angle was then varied in the span wise direction. In addition to this, in an attempt to avoid an increase in stress, the effect of varying the leading edge profile of the blade was investigated. It has been seen that off-design performance is improved by implementing back swept blading at the inlet. Varying the inlet angle in the span wise direction provided more freedom for meeting stress requirements and reduces the negative impact on blade performance at the design point. The blade leading edge profile was seen to offer small improvements during off-design operation with minimal effects on stress within the rotor. However, due to the more pointed nature of the leading edge, the rotor was less tolerant to flow misalignment at the design point. Copyright © 2011 by ASME.


Walkingshaw J.,Queen's University of Belfast | Spence S.,Queen's University of Belfast | Ehrhard J.,IHI Charging Systems International | Thornhill D.,Queen's University of Belfast
Proceedings of the ASME Turbo Expo | Year: 2012

Off-design performance is of key importance now in the design of automotive turbocharger turbines. Due to automotive drive cycles, a turbine which can extract more energy at high pressure ratios and lower rotational speeds is desirable. Typically a radial turbine provides peak efficiency at U/C values of 0.7, but at high pressure ratios and low rotational speeds the U/C value will be low and the rotor will experience high values of positive incidence at the inlet. The positive incidence causes high blade loading resulting in additional tip leakage flow in the rotor as well as flow separation on the suction surface of the blade. An experimental assessment has been performed on a scaled automotive VGS (Variable Geometry System). Three different stator vane positions have been analysed; minimum, 25% and maximum flow position. The first tests were to establish whether positioning the endwall clearance on the hub or shroud side of the stator vanes produced a different impact on turbine efficiency. Following this, a back swept rotor was tested to establish the potential gains to be achieved during off-design operation. A single passage CFD model of the test rig was developed and used to provide information on the flow features affecting performance in both the stator vanes and turbine. It was seen that off-design performance was improved by implementing clearance on the hub side of the stator vanes rather than on the shroud side. Through CFD analysis and tests it was seen that two leakage vortices form, one at the leading edge and one after the spindle of the stator vane. The vortices affect the flow angle at the inlet to the rotor, in the hub region. The flow angle is shifted to more negative values of incidence, which is beneficial at the off-design conditions but detrimental at the design point. The back swept rotor was tested with the hub side stator vane clearance configuration. The efficiency and MFR were increased at the minimum and 25% stator vane position. At the design point the efficiency and MFR were decreased. The CFD investigation showed that the incidence angle was improved at the off-design conditions, for the back swept rotor. This reduction in the positive incidence angle along with the improvement caused by the stator vane tip leakage flow, reduced flow separation on the suction surface of the rotor. At the design point both the tip leakage flow of the stator vanes and the back swept blade angle caused flow separation on the pressure surface of the rotor. This resulted in additional blockage at the throat of the rotor reducing MFR and efficiency. Copyright © 2012 by ASME.


Harley P.,Queen's University of Belfast | Spence S.,Queen's University of Belfast | Filsinger D.,IHI Charging Systems International | Dietrich M.,IHI Charging Systems International | Early J.,Queen's University of Belfast
Proceedings of the ASME Turbo Expo | Year: 2014

This study provides a novel meanline modelling approach for centrifugal compressors. All compressors analysed are of the automotive turbocharger variety and have typical upstream geometry with no casing treatments or pre-swirl vanes. Past experience dictates that inducer recirculation is prevalent toward surge in designs with high inlet shroud to outlet radius ratios; such designs are found in turbocharger compressors due to the demand for operating range. The aim of the paper is to provide further understanding of impeller inducer flow paths when operating with significant inducer recirculation. Using 3D Computational Fluid Dynamics (CFD) and a single-passage model, the flow coefficient at which the recirculating flow begins to develop and the rate at which it grows are used to assess and correlate work and angular momentum delivered to the incoming flow. All numerical modelling has been fully validated using measurements taken from hot gas stand tests for all compressor stages. The new modelling approach links the inlet recirculating flow and the pressure ratio characteristic of the compressor. Typically for a fixed rotational speed, between choke and the onset of impeller inlet recirculation the pressure ratio rises gradually at a rate dominated by the aerodynamic losses. However, in modern automotive turbocharger compressors where operating range is paramount, the pressure ratio no longer changes significantly between the onset of recirculation and surge. Instead the pressure ratio remains relatively constant for reducing mass flow rates until surge occurs. Existing meanline modelling techniques predict that the pressure ratio continues to gradually rise toward surge, which when compared to test data is not accurate. A new meanline method is presented here which tackles this issue by modelling the direct effects of the recirculation. The result is a meanline model that better represents the actual fluid flow seen in the CFD results and more accurately predicts the pressure ratio and efficiency characteristics in the region of the compressor map affected by inlet recirculation. © 2014 by ASME.


Walkingshaw J.,IHI Charging Systems International | Spence S.,Queen's University of Belfast | Filsinger D.,IHI Charging Systems International | Thornhill D.,Queen's University of Belfast
Proceedings of the ASME Turbo Expo | Year: 2014

Automotive manufacturers require improved part load engine performance to further improve fuel economy. For a swing vane VGS (Variable Geometry Stator) turbine this means a more closed stator vane, to deal with the low MFRs (Mass Flow Rates), high PRs (Pressure Ratios) and low rotor rotational speeds. During these conditions the turbine is operating at low velocity ratios. As more energy is available at high pressure ratios and during lower turbocharger rotational speeds, a turbine which is efficient at these conditions is desirable. Another key aspect for automotive manufacturers is engine responsiveness.High inertia designs result in "turbo lag" which means an increased time before the target boost pressure is reached. Therefore, designs with improved performance at low velocity ratios, reduced inertia or an increased swallowing capacity are the current targets for turbocharger manufacturers. To try to meet these design targets a CFD (Computational Fluid Dynamics) study was performed on a turbine wheel using splitter blades. A number of parameters were investigated. These included splitter blade merdional length, blade number and blade angle distribution. The numerical study was performed on a scaled automotive VGS. Three different stator vane positions have been analysed. A single passage CFD model was developed and used to provide information on the flow features affecting performance in both the stator vanes and turbine. Following the CFD investigation the design with the best compromise in terms of performance, inertia and increased MFP (Mass Flow Parameter) was selected for manufacture and testing. Tests were performed on a scaled, low temperature turbine test rig. The aerodynamic flow path of the gas stand was the same as that investigated during the CFD. The test results revealed a design which had similar performance at the closed stator vane positions when compared to the baseline wheel. At the maximum MFR stator vane condition a drop of -0.6% pts in efficiency was seen. However, 5.5% increase in MFP was obtained with the additional benefit of a drop in rotor inertia of 3.7%, compared to the baseline wheel. © 2014 by ASME.


Leonetti M.,Research Institute of Automotive Engineering and Vehicle Engines | Bargende M.,University of Stuttgart | Kreschel M.,IHI Charging Systems International | Meier C.,Mercedes Benz | Schulze H.,Mercedes Benz
SAE Technical Papers | Year: 2015

Due to the demands for today's passenger cars regarding fuel consumption and emissions, exhaust turbo charging has become a fundamental step in achieving these goals. Especially in upper and middle class vehicles it is also necessary to consider the noise comfort. Today, floating bushings are mainly used as radial bearings in turbochargers. In the conventional operating range of the turbocharger dynamic instability occurs in the lubrication films of the bearings. This instability is transferred by structure-borne noise into audible airborne sound and known as constant tone phenomenon. This phenomenon is not the major contributor of the engine noise but its tonal character is very unpleasant. In order to gain a more detailed understanding about the origin of this phenomenon, displacement sensors have been applied to the compressor- and the turbine-side of the rotor, to be able to determine the displacement path. Also, part of this investigation is the measurement of the rotational speed of the floating bearing bushings on turbine-and compressor-side of the turbocharger. The investigations are carried out on turbochargers from 1.6l and 2.0l four-cylinder gasoline engines. The turbocharger has been decoupled from the internal combustion engine to separate the turbocharger related effects from engine related sources. The constant tone can be identified in both the structure-borne and the airborne noise of the turbocharger. At the beginning of the constant tone, during a ramp-up of the rotor, the amplitude of the shaft-movement increases on turbine-and compressor-side. At the same time, a high, jump-like increase in the bearing bushing speed is ascertained. For a detailed analysis, the signals from the displacement sensors are separated into their components, consisting of 1st order of the rotor and the sub-synchronous oscillations. It is shown that the proportion of 1st order in amplitude remains unchanged and the proportion of sub-synchronous oscillation increases significantly. This oscillation is transmitted by the bearing system to the turbocharger housing and emitted from there to structure-borne and airborne noise. Considering now only the sub-synchronous portion of the movement on the turbine-and compressor-side, not only an increase in the amplitude can be seen, but also a change in motion of the rotor at the start of the constant tone, from a conical into a cylindrical motion. © 2015 SAE International.


Patent
Ihi Charging Systems International | Date: 2014-06-06

In a turbine for an exhaust gas turbocharger with a turbine casing having receiving chamber for accommodating a turbine wheel and at least one volute through which the exhaust gas is guided via a feed passage into the receiving chamber and wherein at least one guide element is provided in the turbine casing so as to project into the feed passage in a guide region for guiding the exhaust gas onto the turbine wheel, the guide element comprises a first length region in the axial direction of the turbine, in which the guide element is designed with respect to its aerodynamic properties differently from its aerodynamic design in a second length region adjoining the first length region.

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