Journal articles: 'Turbocharger with variable geometry vanes'

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Wang, Zhihui, Chaochen Ma, Zhi Huang, Liyong Huang, Xiang Liu, and Zhihong Wang. "A novel variable geometry turbine achieved by elastically restrained nozzle guide vanes." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 234, no. 9 (April 8, 2020): 2312–29. http://dx.doi.org/10.1177/0954407020909662.

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Variable geometry turbocharging is one of the most significant matching methods between turbocharger and engine, and has been proven to provide air boost for entire engine speed range as well as to reduce turbo-lag. An elastically constrained device designed for a novel variable geometry turbocharger was presented in this paper. The design of the device is based on the nozzle vane’s self-adaptation under interactions of the elastic force by elastically restrained guide vane and the aerodynamic force from flowing gas. The vane rotation mechanism of the novel variable geometry turbocharger is different from regular commercial variable geometry turbocharger systems, which is achieved by an active control system (e.g. actuator). To predict the aerodynamic performance of the novel variable geometry turbocharger, the flow field of the turbine was simulated using transient computational fluid dynamics software combined with a fluid–structure interaction method. The results show that the function of elastically constrained device has similar effectiveness as the traditional variable geometry turbocharger. In addition, the efficiency of the novel variable geometry turbocharger is improved at most operating conditions. Furthermore, a turbocharged diesel engine was created using the AVL BOOST software to evaluate the benefits of the new variable geometry turbocharger. The proposed novel variable geometry turbocharger can effectively improve the engine performance at mid-high speeds, such that the maximum decrease of brake-specific fuel consumption reaches 17.91% under 100% load and 3600 r/min engine condition. However, the engine power and brake-specific fuel consumption decrease significantly at low engine speed conditions, and the decrease is more than 26% under 1000 r/min.

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Jiang, P. M., and A. Whitfield. "Investigation of Vaned Diffusers as a Variable Geometry Device for Application to Turbocharger Compressors." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 206, no. 3 (July 1992): 209–20. http://dx.doi.org/10.1243/pime_proc_1992_206_179_02.

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The potential of guide vanes as a variable geometry device, placed in the conventional vaneless diffuser, to extend the operating range of a turbocharger compressor is investigated. Vaned diffusers are not normally employed in turbocharger applications as the consequent reduction in operating range is more damaging than the beneficial improvement in peak efficiency and pressure ratio. The variable geometry concept considered here is primarily one in which the guide vanes are introduced at the near surge flow conditions. The leading edge vane angle is set to accept the highly tangential flow at the near surge conditions, and the vane is then used to guide the fluid towards the radial direction in order to reduce the long flow path through the diffuser. Four types of vane arrangements are considered: (a) 12 and 6 full length vanes, with inlet vane angles of 75° and 80°; (b) 6 short inlet vanes to give a high aspect ratio; (c) 12 and 6 short vanes located in the outer half of the vaneless diffuser passage; and (d) double-row vane rings. It is shown that short vanes deployed at the diffuser outlet not only improve the efficiency and pressure ratio but also extend the high flow operating range. Further, the introduction of short inlet vanes with an inlet angle of 80° improves the peak pressure ratio and efficiency, and extends the near surge operating range.

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Lei, Jie, Yan Song Wang, and Hong Juan Ren. "CFD Simulation of Volute of Variable Geometry Turbocharger." Advanced Materials Research 532-533 (June 2012): 287–91. http://dx.doi.org/10.4028/www.scientific.net/amr.532-533.287.

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To study the Volute of Variable Geometry Turbocharger (VGT) flow field and the possibility of providing the basis theory for control strategy and matching with engine, in this paper, a method is presented. The 3D viscous compressible flow in the model of volute and the vanes is simulated by CFD using FVM (Finite Volume Method). And taking some VGT as an example, the simulation is carried out. The result shows that the method can display the distribution of pressure and velocity in the model clearly. The zone and the reasons resulting in loss will be found after analyzing the results, and then the turbocharger can be optimized and redesigned purposeful to reduce the losses resulted from improper figure. The distribution of pressure and velocity at open and close vanes will be found after analyzing the results, and the basis theory for VGT control strategy and matching with engine can be provided.

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Cheng, Li, Pavlos Dimitriou, William Wang, Jun Peng, and Abdel Aitouche. "A novel fuzzy logic variable geometry turbocharger and exhaust gas recirculation control scheme for optimizing the performance and emissions of a diesel engine." International Journal of Engine Research 21, no. 8 (October 31, 2018): 1298–313. http://dx.doi.org/10.1177/1468087418809261.

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Variable geometry turbocharger and exhaust gas recirculation valves are widely installed on diesel engines to allow optimized control of intake air mass flow and exhaust gas recirculation ratio. The positions of variable geometry turbocharger vanes and exhaust gas recirculation valve are predominantly regulated by dual-loop proportional–integral–derivative controllers to achieve predefined set-points of intake air pressure and exhaust gas recirculation mass flow. The set-points are determined by extensive mapping of the intake air pressure and exhaust gas recirculation mass flow against various engine speeds and loads concerning engine performance and emissions. However, due to the inherent nonlinearities of diesel engines and the strong interferences between variable geometry turbocharger and exhaust gas recirculation, an extensive map of gains for the P, I, and D terms of the proportional–integral–derivative controllers is required to achieve desired control performance. The present simulation study proposes a novel fuzzy logic control scheme to determine appropriate positions of variable geometry turbocharger vanes and exhaust gas recirculation valve in real-time. Once determined, the actual positions of the vanes and valve are regulated by two local proportional–integral–derivative controllers. The fuzzy logic control rules are derived based on an understanding of the interactions among the variable geometry turbocharger, exhaust gas recirculation, and diesel engine. The results obtained from an experimentally validated one-dimensional transient diesel engine model showed that the proposed fuzzy logic control scheme is capable of efficiently optimizing variable geometry turbocharger and exhaust gas recirculation positions under transient engine operating conditions in real-time. Compared to the baseline proportional–integral–derivative controllers approach, both engine’s efficiency and total turbo efficiency have been improved by the proposed fuzzy logic control scheme while NOx and soot emissions have been significantly reduced by 34% and 82%, respectively.

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Zhang, Zhongjie, Ruilin Liu, Guangmeng Zhou, Chunhao Yang, Surong Dong, Yufei Jiao, and Jiaming Ma. "Influence of varying altitudes on matching characteristics of the Twin-VGT system with a diesel engine and performance based on analysis of available exhaust energy." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 234, no. 7 (September 18, 2019): 1972–85. http://dx.doi.org/10.1177/0954407019876220.

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A variable geometry turbocharger in series with a variable geometry turbocharger (Twin-VGT) system was designed to improve engine power at high altitudes. The influence of altitudes on the performance of the Twin-VGT system was investigated in the perspective of available exhaust energy. The interaction between exhaust flow characteristics of Twin-VGT and openings of Twin-VGT vanes was theoretically analyzed at different altitudes. Meanwhile, a model of a diesel engine matched with the Twin-VGT system was built to study the matching performance of the Twin-VGT system with engine at different altitudes. The optimal opening maps of both high-pressure and low-pressure VGT vanes at high altitudes were obtained to achieve the maximum engine power. The results showed that the optimal openings of high-pressure and low-pressure VGT vanes decreased with increase in altitudes. The operating points of the two-stage compressors located at the high efficiency region and the compressor efficiency region both exceeded 62% at different altitudes. The global expansion ratio increased with increase in altitudes and reached 4.9 at 5500 m. Compared with the VGT in series with a fixed geometry turbocharger on testing bed, exhaust energy of Twin-VGT turbines at low speeds was utilized reasonably and global pressure ratio increased by 0.69–0.94, while brake-specific fuel consumption decreased by 11.24–33.62% under low speeds above altitudes of 2500 m.

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Kannan, Ramesh, BVSSS Prasad, and Sridhara Koppa. "Transient performance of the mixed flow and radial flow variable geometry turbines for an automotive turbocharger." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 234, no. 19 (April 15, 2020): 3762–75. http://dx.doi.org/10.1177/0954406220916493.

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In our previous paper, the steady-state test results of a mixed flow turbine with variable nozzle vanes for a turbocharger are reported. In this paper, the transient response of the same mixed flow turbine along with that of a similarly sized radial flow turbine is presented. The turbine size is suitable for handling the flow capacity of the diesel engines with swept volume up to 1.5 L. The previous experimental test set up is modified by adding a quick-release valve – actuation system before the turbine inlet to obtain a transient response. The radial and mixed flow turbines are tested for different turbine inlet pressures and for various opening positions of the nozzle vanes while matching the turbine mass flow parameters between radial and mixed flow turbines. Typically at nozzle vane openings corresponding to 50% mass flow parameter and 1.5 bar (abs) pressure at the inlet to the turbine, the transient response time for the turbine with mixed flow variable nozzle vanes configuration is about 0.770 s, as compared to 0.858 s for the turbine with radial flow variable nozzle vanes configuration.

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Ramesh, K., BVSSS Prasad, and K. Sridhara. "A comparative study of the performance of the mixed flow and radial flow variable geometry turbines for an automotive turbocharger." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 233, no. 8 (September 10, 2018): 2696–712. http://dx.doi.org/10.1177/0954406218796043.

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A new design of a mixed flow variable geometry turbine is developed for the turbocharger used in diesel engines having the cylinder capacity from 1.0 to 1.5 L. An equivalent size radial flow variable geometry turbine is considered as the reference for the purpose of bench-marking. For both the radial and mixed flow turbines, turbocharger components are manufactured and a test rig is developed with them to carry out performance analysis. Steady-state turbine experiments are conducted with various openings of the nozzle vanes, turbine speeds, and expansion ratios. Typical performance parameters like turbine mass flow parameter, combined turbine efficiency, velocity ratio, and specific speed are compared for both mixed flow variable geometry turbine and radial flow variable geometry turbine. The typical value of combined turbine efficiency (defined as the product of isentropic efficiency and the mechanical efficiency) of the mixed flow variable geometry turbine is found to be about 25% higher than the radial flow variable geometry turbine at the same mass flow parameter of 1425 kg/s √K/bar m2 at an expansion ratio of 1.5. The velocity ratios at which the maximum combined turbine efficiency occurs are 0.78 and 0.825 for the mixed flow variable geometry turbine and radial flow variable geometry turbine, respectively. The values of turbine specific speed for the mixed flow variable geometry turbine and radial flow variable geometry turbine respectively are 0.88 and 0.73.

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Thomas, Anand Mammen, Jensen Samuel J., Paul Pramod M., A. Ramesh, R. Murugesan, and A. Kumarasamy. "Simulation of a Diesel Engine with Variable Geometry Turbocharger and Parametric Study of Variable Vane Position on Engine Performance." Defence Science Journal 67, no. 4 (June 30, 2017): 375. http://dx.doi.org/10.14429/dsj.67.11451.

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Modelling of a turbocharger is of interest to the engine designer as the work developed by the turbine can be used to drive a compressor coupled to it. This positively influences charge air density and engine power to weight ratio. Variable geometry turbocharger (VGT) additionally has a controllable nozzle ring which is normally electro-pneumatically actuated. This additional degree of freedom offers efficient matching of the effective turbine area for a wide range of engine mass flow rates. Closing of the nozzle ring (vanes tangential to rotor) result in more turbine work and deliver higher boost pressure but it also increases the back pressure on the engine induced by reduced turbine effective area. This adversely affects the net engine torque as the pumping work required increases. Hence, the optimum vane position for a given engine operating point is to be found through simulations or experimentation. A thermodynamic simulation model of a 2.2l 4 cylinder diesel engine was developed for investigation of different control strategies. Model features map based performance prediction of the VGT. Performance of the engine was simulated for steady state operation and validated with experimentation. The results of the parametric study of VGT’s vane position on the engine performance are discussed.

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Wang, Zhihui, Chaochen Ma, Hang Zhang, and Fei Zhu. "A novel pulse-adaption flow control method for a turbocharger turbine: Elastically restrained guide vane." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 234, no. 13 (March 2, 2020): 2581–94. http://dx.doi.org/10.1177/0954406220908623.

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A turbocharger is a key enabler for energy conservation in an internal combustion engine. The turbine in a turbocharger is fed by highly pulsating gas flow due to the reciprocating engine, resulting in significant deterioration of the turbocharger performance. To solve this problem, a novel pulse-optimized regulation mechanism named ‘elastically restrained guide vane’ for a novel variable geometry turbocharger is proposed in this paper. The new mechanism regulates the instantaneous flow angle at turbine inlet due to guide vane's self-adaptive rotation under interactions of the elastic force by elastically restrained guide vane and the aerodynamic force from flowing gas, which is different from the traditional variable geometry turbocharger that is achieved by an active control system (e.g. actuator). To investigate the effectiveness of the novel method, a double-passage computational fluid dynamics model is built in ANSYS CFX software combined with a fluid-structure interaction method. The results demonstrate that the pulse-adaptive regulation method can effectively adjust the nozzle opening according to the different pulsating pressures at turbine inlet. Subsequently, based on the calibrated models, the numerical simulation concentrates on the potential gain in turbine eventual power output and the exhaust energy recover as well as the corresponding effects on efficiency as a result of operating the turbocharger in its elastically restrained guide vane mode compared to its operation as a conventional variable geometry turbocharger.

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Hatami, M., M. C. M. Cuijpers, and M. D. Boot. "Experimental optimization of the vanes geometry for a variable geometry turbocharger (VGT) using a Design of Experiment (DoE) approach." Energy Conversion and Management 106 (December 2015): 1057–70. http://dx.doi.org/10.1016/j.enconman.2015.10.040.

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Eynon, P. A., and A. Whitfield. "The effect of low-solidity vaned diffusers on the performance of a turbocharger compressor." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 211, no. 5 (May 1, 1997): 325–39. http://dx.doi.org/10.1243/0954406971522088.

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The design of low-solidity diffuser vanes and the effect on the performance of a turbo-charger compressor is discussed. The effect of vane number and turning angle was investigated while maintaining a basic design with a solidity of 0.69 and a leading edge angle of 75°. This large leading edge angle was specifically chosen so that the vane would be aligned with the low flowrates close to surge. Tests were initially conducted with six, eight and ten vanes and a turning angle of 10°. Based on these results the ten-vane design was selected for further investigation with 15 and 20° of vane turning; this led to vane exit angles of 60 and 55° respectively. All results are compared with those obtained with the standard vaneless diffuser configuration and it was shown that all designs increased and shifted the peak pressure ratio to reduced flowrates. The peak efficiency was reduced relative to that obtained with the vaneless diffuser. Despite the low-solidity configuration none of the vane designs provided a broad operating range without the use of a variable geometry configuration. This was attributed to the selection of a large leading edge vane angle.

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Jiao, K., H. Sun, X. Li, H. Wu, E. Krivitzky, T. Schram, and L. M. Larosiliere. "Numerical investigation of the influence of variable diffuser vane angles on the performance of a centrifugal compressor." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 223, no. 8 (August 1, 2009): 1061–70. http://dx.doi.org/10.1243/09544070jauto1202.

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In this study, the performance of a turbocharger compressor system for light-duty diesels, encompassing the airflow geometry from impeller inlet to volute exit, has been simulated numerically, and the effects of variable diffuser vane angles on the compressor performance and operating range have been investigated. It is found that the angle of the diffuser vane has significant influence on the compressor operating range, and optimized design of the variable diffuser vane angle can increase the stable operating range and improve the compressor efficiency significantly when compared with fixed diffuser vane angles and vaneless designs. However, changing the diffuser vane angle alone may not achieve the full control of the operating range of a compressor desired. Other technologies (e.g. variable inlet guide vanes, casing treatment, or optimum impeller design) may also be necessary to achieve the widest operating range required.

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Zeng, Tao, and Guoming G. Zhu. "Control-oriented turbine power model for a variable-geometry turbocharger." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 232, no. 4 (May 14, 2017): 466–81. http://dx.doi.org/10.1177/0954407017702996.

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A control-oriented model for the variable-geometry turbocharger is critical for model-based variable-geometry turbocharger control design. Typically, the variable-geometry turbocharger turbine power is modeled with a fixed mechanical efficiency of the turbocharger on the assumption of an isentropic process. The fixed-efficiency approach is an oversimplification and may lead to modeling errors because of an overpredicted or underpredicted compressor power. This leads to the use of lookup-table-based approaches for defining the mechanical efficiency of the turbocharger. Unfortunately, since the vane position of a variable-geometry turbocharger introduces a third dimension into these maps, real-time implementation requires three-dimensional interpolations with increased complexity. Map-based approaches offer greater fidelity in comparison with the fixed-efficiency approach but may introduce additional errors due to interpolation between the maps and extrapolation to extend the operational range outside the map. Interpolation errors can be managed by using dense maps with extensive flow bench testing; smooth extrapolation is necessary when the turbine is operated outside the mapped region, e.g. in low-flow and low-speed conditions. Extending the map to this region requires very precise flow control and measurement using a motor-driven compressor, which currently is not a standard test procedure. In this paper, a physics-based control-oriented model of the turbine power and the associated power loss is proposed and developed, where the turbine efficiency is modeled as a function of both the vane position of the variable-geometry turbocharger and the speed of the turbine shaft. As a result, the proposed model eliminates the interpolation errors with smooth extension to operational conditions outside typically mapped regions.

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Dumitrache, Constantin, Ioan Calimanescu, and Corneliu Comandar. "Naval Centrifugal Compressor Design Using CAD Solutions." Applied Mechanics and Materials 658 (October 2014): 59–64. http://dx.doi.org/10.4028/www.scientific.net/amm.658.59.

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Centrifugal compressors of turbochargersoperate in a wide range of rotational speeds, which depends on the load of the supercharged engine. Current designs of turbocharger compressors exhibit high efficiencies accompanied by high flow capacities [1]. Consequences of aerodynamic optimization are high mean stress values in the blades due to centrifugal loading as well as dynamic stresses due to blade vibrations. Blade vibrations in a turbocharger compressor are assumed to be predominantly excited by unsteady aerodynamic forces [2]. These forces are caused by a variety of sources influencing the flow. Examples include the geometry of the flow channel, elbows, the diffuser vanes or struts. Therefore, an understanding of FSI is essential for further design optimizations.

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Tesfamichael Baheta, Aklilu, S. I. Gilani, and Shaharin Anwar Sulaiman. "Performance Evaluation of a Variable Geometry Gas Turbine in a CHP Plant." Applied Mechanics and Materials 798 (October 2015): 59–63. http://dx.doi.org/10.4028/www.scientific.net/amm.798.59.

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This study is to develop mathematical models and evaluate the performance of a gas turbine with variable geometry compressor working in a CHP plant. A single shaft gas turbine plant can maintain the exhaust gas temperature if the load is not below 50 % of the full load by simultaneously regulating the compressor variable vanes position and fuel flow. For load less than 50% the engine is running to meet the power demand. This is achieved by controlling the fuel flow and air bleed at the downstream of the compressor to avoid surge formation while variable vanes are opened fully. To accommodate change of compressor parameters during variable vanes re-stagger correction coefficients are introduced. A behavior of a 4.2 MW gas turbine performance was evaluated. The effect of variation of load and ambient temperature on the gas turbine specific fuel consumption, temperature, pressure ratio, variable vanes opening and efficiency were examined. Comparison between the field data and simulation results demonstrate good agreement. The off-design calculation was done by in-house developed program in MATLAB environment.

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Gabriel, Holger, Stefan Jacob, Uwe Münkel, Helmut Rodenhäuser, and Hans-Peter Schmalzl. "The turbocharger with variable turbine geometry for gasoline engines." MTZ worldwide 68, no. 2 (February 2007): 7–10. http://dx.doi.org/10.1007/bf03226804.

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Dambrosio, L., G. Pascazio, and B. Fortunato. "Fuzzy logic controller applied to a variable geometry turbine turbocharger." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 219, no. 11 (November 1, 2005): 1347–60. http://dx.doi.org/10.1243/095440705x35008.

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This paper provides an adaptive technique for the control of a variable geometry turbine (VGT) in a turbocharged compression ignition engine. The adaptive control is based on a fuzzy logic control scheme and a least-squares parameter estimator algorithm. In order to test the performance of the proposed control technique, a numerical model of the engine has been used, which employs a thermodynamic (zero-dimensional) approach. The paper will show that the fuzzy logic control technique is able to take into account the non-linearity of the controlled system and to reject white noise affecting the measurement chain.

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Bahiuddin, Irfan, Saiful Amri Mazlan, Fitrian Imaduddin, and Ubaidillah. "A new control-oriented transient model of variable geometry turbocharger." Energy 125 (April 2017): 297–312. http://dx.doi.org/10.1016/j.energy.2017.02.123.

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Tang, Huayin, Colin Copeland, Sam Akehurst, Chris Brace, Peter Davies, Ludek Pohorelsky, Les Smith, and Geoff Capon. "A novel predictive semi-physical feed-forward turbocharging system transient control strategy based on mean-value turbocharger model." International Journal of Engine Research 18, no. 8 (October 7, 2016): 765–75. http://dx.doi.org/10.1177/1468087416670052.

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Variable geometry turbine is a technology that has been proven on diesel engines. However, despite the potential to further improve gasoline engines’ fuel economy and transient response using variable geometry turbine, controlling the variable geometry turbine during transients is challenging due to its highly non-linear behaviours especially on gasoline applications. After comparing three potential turbocharger transient control strategies, the one that predicts the turbine performances for a range of possible variable geometry turbine settings in advance was developed and validated using a high-fidelity engine model. The proposed control strategy is able to capture the complex transient behaviours and achieve the optimum variable geometry turbine trajectories. This improved the turbocharger response time by more than 14% compared with a conventional proportional–integral–derivative controller, which cannot achieve target turbocharge speed in all cases. Furthermore, the calibration effort required can be significantly reduced, offering significant benefits for powertrain developers. It is expected that the structure of this transient control strategy can also be applied to complex air-path systems.

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Whitfield, A., and A. J. Sutton. "The Effect of Vaneless Diffuser Geometry on the Surge Margin of Turbocharger Compressors." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 203, no. 2 (April 1989): 91–98. http://dx.doi.org/10.1243/pime_proc_1989_203_154_02.

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A study into the effect of two methods of changing the geometry of a vaneless diffuser on the performance of the compressor of a road haulage diesel engine turbocharger is described. The development of compressor variable geometry will enable the full potential of variable geometry turbines to be realized. This will give a more flexible power unit which will provide, for example, better low-speed torque and hence a smaller gearbox, and shorter journey times or larger payloads than are currently the practice. The disadvantages are added complexity and cost in the relatively simple turbocharger, and the need for an engine management system. The latter is currently being implemented on many vehicles to meet tight emissions regulations in Europe and elsewhere, and is thus not a drawback limited to variable geometry turbocharging. A compressor test facility, including appropriate instrumentation and a computer-based data-acquisition system, was constructed with the specific aim of investigating the unstable flow regime prior to and including surge. Alternative fixed vaneless diffuser geometries were designed to simulate a variable geometry diffuser which could be achieved through a flexing diffuser wall and a sliding throttle ring. Both the converging wall and throttle ring arrangement moved the peak pressure ratio to lower flowrates, and at the near surge flowrates (where the device would be introduced, when operating in a variable geometry mode) improvements in both pressure ratio and efficiency are shown. While the converging wall concept exhibited slightly better aerodynamic performance than the throttle ring, it has implementation difficulties with respect to material integrity under continuous flexing when developed to a fully variable geometry device. The simplicity of the sliding throttle ring makes it a more viable proposition. Prototype variable geometry (VG) devices have been constructed with a view to further rig and engine testing.

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Pesiridis, Apostolos, Botev Vassil, Muhammad Padzillah, and Ricardo Martinez-Botas. "A Comparison of flow control devices for variable geometry turbocharger application." International Journal of Automotive Engineering and Technologies 3, no. 1 (April 3, 2014): 1. http://dx.doi.org/10.18245/ijaet.84934.

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Rajoo, Srithar, Alessandro Romagnoli, and Ricardo F. Martinez-Botas. "Unsteady performance analysis of a twin-entry variable geometry turbocharger turbine." Energy 38, no. 1 (February 2012): 176–89. http://dx.doi.org/10.1016/j.energy.2011.12.017.

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Tian, Feng, Guo Feng Ren, Bin Yan, Guo Qiang Ao, and Lin Yang. "Optimization of Hybrid Turbocharger Applied on Common Rail Diesel Engine with Exhaust Gas Recirculation." Applied Mechanics and Materials 246-247 (December 2012): 84–88. http://dx.doi.org/10.4028/www.scientific.net/amm.246-247.84.

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Turbocharger is an effective technique to achieve higher thermal efficiency reduced emissions. And hybrid turbocharger is proven to be a promising technique to eliminate the well-known 'turbo-lag' effect of the turbocharger. In this paper, a global optimization of hybrid turbocharger technique with variable geometry turbine and exhaust gas recirculation was carried out. The diesel engine was modeled by GT-SUITE software, which is a 1D simulation environment. Moreover, a dynamic programming based optimizer, which was developed in Simulink, was integrated with the diesel engine model. Simulations results show that the optimized parameters can improve the engine fuel economy significantly under Chinese typical urban driving cycle.

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Salvage, J. W. "Development of a Centrifugal Compressor With a Variable Geometry Split-Ring Pipe Diffuser." Journal of Turbomachinery 121, no. 2 (April 1, 1999): 295–304. http://dx.doi.org/10.1115/1.2841314.

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Higher noise levels resulted when a compressor was scaled to larger capacity. The machine’s sound pressure level was relieved by increasing the distance between the impeller blade tip and diffuser leading edge. However, the part-load surge line deteriorated severely as a consequence. A variable geometry pipe diffuser solved this problem, permitting operation at stringent off-design conditions. The addition of a variable diffuser permits compressor selection very near its most efficient full-load operating point, without regard for limitations normally imposed by part-load requirements. The principal lessons learned during aerodynamic design refinement include (a) how performance and surge depend upon positioning the variable inlet guide vanes and variable diffuser, and (b) how to define simultaneous variation of inlet guide vanes and diffuser for specific operational objectives. Generally, each operating point requires a unique setting of the variable components to achieve maximum efficiency. However, linked movement is shown to yield both a satisfactory surge line and improved performance for most applications when compared to a compressor without the variable geometry pipe diffuser.

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Feneley, Adam J., Apostolos Pesiridis, and Amin Mahmoudzadeh Andwari. "Variable Geometry Turbocharger Technologies for Exhaust Energy Recovery and Boosting‐A Review." Renewable and Sustainable Energy Reviews 71 (May 2017): 959–75. http://dx.doi.org/10.1016/j.rser.2016.12.125.

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Wöhr, Michael, Elias Chebli, Markus Müller, Hans Zellbeck, Johannes Leweux, and Andreas Gorbach. "Development of a turbocharger compressor with variable geometry for heavy-duty engines." International Journal of Engine Research 16, no. 1 (December 17, 2014): 23–30. http://dx.doi.org/10.1177/1468087414562457.

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Gao, Jie, Ming Wei, Pengfei Liu, Guoqiang Yue, and Qun Zheng. "Improved clearance designs to minimize aerodynamic losses in a variable geometry turbine vane cascade." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 232, no. 17 (September 8, 2017): 3085–101. http://dx.doi.org/10.1177/0954406217729716.

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Variable geometry turbine exists in small mobile gas turbines or some marine gas turbines to enhance the part-load performance. However, there are efficiency penalties associated with the vane partial gap, which is needed for the movement of variable vanes. This paper investigates the vane-end clearance leakage flow for a flat tip, a cavity tip, a winglet tip, a tip with passive injection, and a cavity-winglet tip to assess the possibility of minimizing vane-end clearance losses in a variable geometry turbine cascade. First, calculations were done at the test rig conditions for comparison with measured data, and they were used for validation of computational fluid dynamics model. Then, numerical calculations were done for turbine typical conditions. Specific flow structures of the various clearance designs of variable vanes are described, and then the effects of vane turning, including exit Mach numbers of 0.34, 0.44, and 0.54 as well as turning angles of –6°, 0°, and 6° on total pressure losses and outflow yaw angle for different vane tips are shown. In addition, the sensitivity of aerodynamic losses to vane tip gap height is evaluated. Results show that the strong interactions near the tip endwall region change the near-tip loading distribution significantly. With winglet and cavity-winglet tip designs, the loading distribution becomes very similar to the typical fixed vane, and the total loading is reduced, thus reducing the vane-end losses. Among the different vane tips presented, the cavity-winglet tip achieves the best aerodynamic performance, and the cavity tip has the lowest sensitivity to vane tip gap height. Overall, the cavity-winglet tip is found to be the best choice for variable vanes. The research results can provide useful reference for the vane design in a real high endwall-angle variable geometry turbine.

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Nugraha, Satria Indra, Budi Setiyono, and Yuli Christyono. "SIMULASI SISTEM KONTROL KONTROL TEKANAN KOMPRESOR PADA ELECTRICALLY ASSISTED TURBOCHARGER DENGAN METODE CASCADE FUZZY-PI." TRANSIENT 7, no. 1 (March 13, 2018): 131. http://dx.doi.org/10.14710/transient.7.1.131-137.

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Turbocharger adalah teknologi yang mulai banyak digunakan pada mobil penumpang. Namun turbocharger yang dipasangkan pada spark ignition engine (SI engine) mengalami turbolag dikarenakan perubahan sudut bukaan throttle yang sering terjadi. Hal ini menyebabkan respon sistem menjadi lambat. Beberapa metode yang dilakukan untuk mengurangi turbolag yaitu : penggunaan mesin dengan rasio kompresi tinggi, penempatan katup throttle sebelum kompresor, variable geometry turbocharger, dan pemendekan pipa inlet dan exhaust. Akan tetapi, metode tersebut tidak dapat mengeliminasi turbolag seluruhnya. Salah satu metode untuk mengeliminasi turbolag adalah dengan aktuator tambahan seperti motor DC sebagai electric assist. Motor DC sebagai electric assist dapat memberikan torsi bantu pada turbocharger untuk menghasilkan respon sistem untuk mencapai tekanan kompresor ideal dengan cepat dan stabil pada keadaan tunaknya. Pada penelitian ini dirancang dua struktur sistem kontrol tekanan kompresor pada electrically assisted turbocharger dengan metode cascade fuzzy-PI sehingga motor DC sebagai aktuator tambahan dapat menghasilkan torsi bantu yang sesuai. Hasil pengujian menunjukkan settling time masing-masing struktur 95,99 % dan 95,17 % lebih singkat dibanding sistem turbocharger konvensional.

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29

Huang, Qiangqiang, and Xinqian Zheng. "Potential of variable diffuser vanes for extending the operating range of compressors and for improving the torque performance of turbocharged engines." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 231, no. 4 (August 20, 2016): 555–66. http://dx.doi.org/10.1177/0954407016661440.

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Turbocharging plays a significant role in internal-combustion engines. For engines in the future or for engines operating at a high altitude, compressors which are able to deliver a high pressure ratio are preferable. However, the poor low-end torque characteristics of turbocharged engines, which are often restricted by the narrow operating range of compressors at a high pressure ratio, result in a severe problem for turbocharging. The use of variable diffuser vanes is an effective method to increase the operating range, but the potential of an extended operating range at a high pressure ratio and improvement in the torque performance of engines is unclear. Nowadays, the pressure ratio of a turbocharger compressor may be only 1–4. Because of the increase in the pressure ratio, estimating the potential is ultimately worthwhile. In this paper the performances of a centrifugal compressor with different diffuser vane angles are investigated, the range extension and the improvement in the torque performance which benefited from variable diffuser vanes are estimated and the mechanisms for range extension are revealed. The approach includes steady three-dimensional Reynolds-averaged Navier–Stokes simulations and theoretical analysis. Adjusting the vane angle from −10° to 10° improves the operating range of a compressor from 23.5% (with fixed vanes) to 54.9% at a pressure ratio of 4.8. The range extension is obtained by utilizing the shifts in the choke line and the surge line. A method of assessing the choking component based on the simulation results is proposed. The diffuser, the flow stability of which was enhanced comparatively by closing it (pivoting the vanes by −10° and −5°), contributes mainly to reducing the surge flow. With this range extension, the improvement in the maximum torque is estimated to be 78%.

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Song, Kang, Devesh Upadhyay, and Hui Xie. "A physics-based turbocharger model for automotive diesel engine control applications." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 233, no. 7 (May 19, 2018): 1667–86. http://dx.doi.org/10.1177/0954407018770569.

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Control-oriented models of turbocharger processes such as the compressor mass flow rate, the compressor power, and the variable geometry turbine power are presented. In a departure from approaches that rely on ad hoc empirical relationships and/or supplier provided performance maps, models based on turbomachinery physics and known geometries are attempted. The compressor power model is developed using Euler’s equations of turbomachinery, where the gas velocity exiting the rotor is estimated from an empirically identified correlation for the ratio between the radial and tangential components of the gas velocity. The compressor mass flow rate is modeled based on mass conservation, by approximating the compressor as an adiabatic converging-diverging nozzle with compressible fluid driven by external work input from the compressor wheel. The variable geometry turbine power is developed with Euler’s equations, where the turbine exit swirl and the gas acceleration in the vaneless space are neglected. The gas flow direction into the turbine rotor is assumed to align with the orientation of the variable geometry turbine vane. The gas exit velocity is calculated, similar to the compressor, based on an empirical model for the ratio between the turbine rotor inlet and exit velocities. A power loss model is also proposed that allows proper accounting of power transfer between the turbine and compressor. Model validation against experimental data is presented.

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31

Mastrovito, M., L. Gaballo, and L. Dambrosio. "Diesel engine variable-geometry turbine turbocharger controlled by a multi-agent-based algorithm." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 222, no. 8 (August 2008): 1459–70. http://dx.doi.org/10.1243/09544070jauto493.

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Kozak, Dariusz, Paweł Mazuro, and Andrzej Teodorczyk. "Numerical Simulation of Two-Stage Variable Geometry Turbine." Energies 14, no. 17 (August 27, 2021): 5349. http://dx.doi.org/10.3390/en14175349.

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The modern internal combustion engine (ICE) has to meet several requirements. It has to be reliable with the reduced emission of pollutant gasses and low maintenance requirements. What is more, it has to be efficient both at low-load and high-load operating conditions. For this purpose, a variable turbine geometry (VTG) turbocharger is used to provide proper engine acceleration of exhaust gases at low-load operating conditions. Such a solution is also efficient at high-load engine operating conditions. In this paper, the result of an unsteady, three-dimensional (3D) simulation of the variable two-stage turbine system is discussed. Three different VTG positions were considered for those simulations, along with three different turbine speeds. The turbine inlet was modeled as six equally placed exhaust pipes for each cylinder to eliminate the interference of pressure waves. The flow field at the outlet of the 1st stage nozzle vane and 2nd stage rotor was investigated. The simulations showed that the variable technologies significantly improve the efficiency of the two-stage turbine system. The highest overall efficiency of the two-stage system was achieved at 60,000 rpm and 11° VTG position.

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33

Pesiridis, Apostolos, and Ricardo F. Martinez-Botas. "Experimental Evaluation of Active Flow Control Mixed-Flow Turbine for Automotive Turbocharger Application." Journal of Turbomachinery 129, no. 1 (February 1, 2005): 44–52. http://dx.doi.org/10.1115/1.2372778.

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In the current paper we introduce an innovative new concept in turbochargers—that of using active control at the turbine inlet with the aim of harnessing the highly dynamic exhaust gas pulse energy emanating at high frequency from an internal combustion engine, in order to increase the engine power output and reduce its exhaust emissions. Driven by the need to comply to increasingly strict emissions regulations as well as continually striving for better overall performance, the active control turbocharger is intended to provide a significant improvement over the current state of the art in turbocharging: the Variable Geometry Turbocharger (VGT). The technology consists of a system and method of operation, which regulate the inlet area to a turbocharger inlet, according to each period of engine exhaust gas pulse pressure fluctuation, thereby actively adapting to the characteristics of the high frequency, highly dynamic flow, thus taking advantage of the highly dynamic energy levels existent through each pulse, which the current systems do not take advantage of. In the Active (Flow) Control Turbocharger (ACT) the nozzle is able to adjust the inlet area at the throat of the turbine inlet casing through optimum amplitudes, at variable out-of-phase conditions and at the same frequency as that of the incoming exhaust stream pulses. Thus, the ACT makes better use of the exhaust gas energy of the engine than a conventional VGT. The technology addresses, therefore, for the first time the fundamental problem of the poor generic engine-turbocharger match, since all current state of the art systems in turbocharging are still passive receivers of this highly dynamic flow without being able to provide optimum turbine inlet geometry through each exhaust gas pulse period. The numerical simulation and experimental work presented in this paper concentrates on the potential gain in turbine expansion ratio and eventual power output as well as the corresponding effects on efficiency as a result of operating the turbocharger in its active control mode compared to its operation as a standard VGT.

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Wirkowski, Paweł. "Modelling the characteristics of axial compressor of variable flow passage geometry, working in the gas turbine engine system." Polish Maritime Research 14, no. 3 (July 1, 2007): 27–32. http://dx.doi.org/10.2478/v10012-007-0015-z.

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Modelling the characteristics of axial compressor of variable flow passage geometry, working in the gas turbine engine system This paper concerns application of mathematical modelling methods to analyzing gas-dynamic processes in marine gas turbines. Influence of geometry changes in axial compressor flow passage on kinematical air flow characteristics, are presented. The elaborated mathematical model will make it possible to realize - in the future - simulative investigations of gas-dynamic processes taking place in a compressor fitted with controllable guide vanes.

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35

Yin, Yong, Zhengbai Liu, Weilin Zhuge, Rongchao Zhao, Yanting Zhao, Zhen Chen, and Jiao Mi. "Experimental study on the performance of a turbocompound diesel engine with variable geometry turbocharger." International Journal of Fluid Machinery and Systems 9, no. 4 (December 31, 2016): 332–37. http://dx.doi.org/10.5293/ijfms.2016.9.4.332.

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36

Rajamani, R. "Control of a variable-geometry turbocharged and wastegated diesel engine." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 219, no. 11 (November 1, 2005): 1361–68. http://dx.doi.org/10.1243/095440705x34964.

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This paper addresses the problem of controlling a turbocharged diesel engine so as to minimize NOx and smoke emissions while ensuring that the driver's torque demands are met. A diesel engine equipped with a variable-geometry turbocharger (VGT) and an exhaust gas recirculation (EGR) valve is considered. The technical challenges in the control design task include the multivariable non-linear dynamics of the system and the unavailability of key states for feedback. A control strategy based on non-linear control synthesis is developed and shown accurately to control the air-fuel ratio (AFR) and the burned gas fraction in the intake manifold, F1, to desired values in the presence of changing operating conditions. The variables F1 and AFR are shown to be crucial for feedback. Since neither of these variables can be measured, an observer based on flow and pressure sensor measurements is developed for their real-time estimation. Lyapunov theory is used to show that the developed observer is asymptotically stable. Simulation results confirm the performance of the observer and the observer-based feedback controller. The importance of the developed observer extends beyond the application discussed in this paper. It could be useful for a wide variety of different control and diagnostic applications in diesel engines.

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37

Chauvin, J., O. Grondin, and P. Moulin. "Control Oriented Model of a Variable Geometry Turbocharger in an Engine with Two EGR Loops." Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles 66, no. 4 (July 2011): 563–71. http://dx.doi.org/10.2516/ogst/2011103.

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38

Chauvin, Jonathan, Olivier Grondin, and Philippe Moulin. "Control oriented model of a variable geometry turbocharger in an engine with two EGR loops." IFAC Proceedings Volumes 42, no. 26 (2009): 64–70. http://dx.doi.org/10.3182/20091130-3-fr-4008.00009.

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39

Imakiire, Koichiro, Masanori Kimura, Eito Matsuo, and Bunichi Nagata. "Development of MET-SR-VG Turbocharger Driven by Radial Flow Turbine with Variable Geometry Nozzle." JOURNAL OF THE MARINE ENGINEERING SOCIETY IN JAPAN 26, no. 6 (1991): 287–92. http://dx.doi.org/10.5988/jime1966.26.6_287.

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40

Park, Yeong-Seop, Byoung-Gul Oh, Min-Kwang Lee, and Myoung-Ho SunWoo. "Development of Turbine Mass Flow Rate Model for Variable Geometry Turbocharger Using Artificial Neural Network." Transactions of the Korean Society of Mechanical Engineers B 34, no. 8 (August 1, 2010): 783–90. http://dx.doi.org/10.3795/ksme-b.2010.34.8.783.

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41

Jacobs, Timothy J., Chad Jagmin, Wesley J. Williamson, Zoran S. Filipi, Dennis N. Assanis, and Walter Bryzik. "Performance and emission enhancements of a variable geometry turbocharger on a heavy-duty diesel engine." International Journal of Heavy Vehicle Systems 15, no. 2/3/4 (2008): 170. http://dx.doi.org/10.1504/ijhvs.2008.022241.

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42

Tsalavoutas, A., K. Mathioudakis, A. Stamatis, and M. Smith. "Identifying Faults in the Variable Geometry System of a Gas Turbine Compressor." Journal of Turbomachinery 123, no. 1 (February 1, 2000): 33–39. http://dx.doi.org/10.1115/1.1330267.

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The influence of faults in the variable geometry (variable stator vanes) system of a multistage axial compressor on the performance of an industrial gas turbine is investigated. An experimental investigation has been conducted, by implanting such faults into an operating gas turbine. The faults examined are individual stator vane mistunings of different magnitudes and located at different stages. Fault identification is based on the aerothermodynamic measurement data and is achieved by employing two different techniques, namely adaptive performance modeling and monitoring the circumferential distribution of the turbine exit temperature. It is observed that the deviations of the health indices produced by an adaptive performance model form patterns that can be used to identify the faults. The patterns characterize both the kind and the magnitude of the fault. On the other hand, the turbine exit temperature profile is also influenced and its change can be used as additional information, to increase the confidence level of the diagnosis (contrary to customary practice, which expects temperatures profiles to reflect only burner or turbine malfunctions).

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43

Camporeale, S. M., B. Fortunato, and A. Dumas. "Dynamic modelling of recuperative gas turbines." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 214, no. 3 (May 1, 2000): 213–25. http://dx.doi.org/10.1243/0957650001538317.

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This paper describes the mathematical model and the computational procedure adopted for the development of a modularly structured computer code able to simulate the dynamic behaviour of recuperative gas turbine power plants. For accurate simulation of the turbine components, the model includes a stage-by-stage procedure for the air-cooled turbine based on the blade geometry and the characteristics of the cooling system. The counter-flow surface heat exchanger, assumed as recuperator, is described by a set of partial differential equations, giving à One-dimensional description of the temperature for air, hot gas and metal. A single-shaft recuperated cycle gas turbine, provided with compressor variable inlet guide vanes, is analysed. The transient cases caused by a step variation in the fuel flow and compressor guide vanes geometry are simulated and a linearized model is obtained, in order to identify the dynamic behaviour of the gas turbine and to design a multivariable controller. Finally, the transient case of a controlled turbine after a sudden variation in the electric load is simulated.

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44

Ahmed, Fayez Shakil, Salah Laghrouche, Adeel Mehmood, and Mohammed El Bagdouri. "Estimation of exhaust gas aerodynamic force on the variable geometry turbocharger actuator: 1D flow model approach." Energy Conversion and Management 84 (August 2014): 436–47. http://dx.doi.org/10.1016/j.enconman.2014.03.080.

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45

Sehra, A., J. Bettner, and A. Cohn. "Design of a High-Performance Axial Compressor for Utility Gas Turbine." Journal of Turbomachinery 114, no. 2 (April 1, 1992): 277–86. http://dx.doi.org/10.1115/1.2929141.

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An aerodynamic design study to configure a high-efficiency industrial-size gas turbine compressor is presented. This study was conducted using an advanced aircraft engine compressor design system. Starting with an initial configuration based on conventional design practice, compressor design parameters were progressively optimized. To improve the efficiency potential of this design further, several advanced design concepts (such as stator ends bends and velocity controlled airfoils) were introduced. The projected poly tropic efficiency of the final advanced concept compressor design having 19 axial stages was estimated at 92.8 percent, which is 2 to 3 percent higher than the current high-efficiency aircraft turbine engine compressors. The influence of variable geometry on the flow and efficiency (at design speed) was also investigated. Operation at 77 percent design flow with inlet guide vanes and front five variable stators is predicted to increase the compressor efficiency by 6 points as compared to conventional designs having only the inlet guide vane as variable geometry.

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46

Coppinger, M., and E. Swain. "Performance prediction of an industrial centrifugal compressor inlet guide vane system." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 214, no. 2 (March 1, 2000): 153–64. http://dx.doi.org/10.1243/0957650001538254.

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Variable inlet guide vanes (VIGVs) can significantly extend the stable operating range of industrial centrifugal compressors as a result of imparting swirl to the inlet flow. Typical setting angles range from −20° to +80°; therefore the vanes are normally made from flat plate. An undesirable consequence of the large setting angles required by the vanes is a pressure loss, leading to a decrease in the overall stage efficiency. An ideal inlet guide vane system will therefore induce large swirl angles in the inlet flow with a low associated pressure loss. Efforts have been made to determine the performance characteristics of an existing VIGV design using both an experimental test facility and numerical techniques. The results obtained from these techniques are far more comprehensive than earlier full-scale performance testing. Validation of the performance of the existing design using these techniques has led to the development of a new vane design and potential improvements to the inlet ducting geometry. The test techniques and resulting analyses of the existing design are presented here together with some analyses and predictions of the performance of the improved VIGV system design.

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47

Hu, Yang, Li, Li, and Bai. "Intelligent Control Strategy for Transient Response of a Variable Geometry Turbocharger System Based on Deep Reinforcement Learning." Processes 7, no. 9 (September 6, 2019): 601. http://dx.doi.org/10.3390/pr7090601.

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Deep reinforcement learning (DRL) is an area of machine learning that combines a deep learning approach and reinforcement learning (RL). However, there seem to be few studies that analyze the latest DRL algorithms on real-world powertrain control problems. Meanwhile, the boost control of a variable geometry turbocharger (VGT)-equipped diesel engine is difficult mainly due to its strong coupling with an exhaust gas recirculation (EGR) system and large lag, resulting from time delay and hysteresis between the input and output dynamics of the engine’s gas exchange system. In this context, one of the latest model-free DRL algorithms, the deep deterministic policy gradient (DDPG) algorithm, was built in this paper to develop and finally form a strategy to track the target boost pressure under transient driving cycles. Using a fine-tuned proportion integration differentiation (PID) controller as a benchmark, the results show that the control performance based on the proposed DDPG algorithm can achieve a good transient control performance from scratch by autonomously learning the interaction with the environment, without relying on model supervision or complete environment models. In addition, the proposed strategy is able to adapt to the changing environment and hardware aging over time by adaptively tuning the algorithm in a self-learning manner on-line, making it attractive to real plant control problems whose system consistency may not be strictly guaranteed and whose environment may change over time.

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Schaffnit, Jochen, Oliver Nelles, Rolf Isermann, and Wolfram Schmid. "Local Linear Model Tree (LOLIMOT) for Nonlinear System Identification of a Turbocharger with Variable Turbine Geometry (VTG)." IFAC Proceedings Volumes 33, no. 15 (June 2000): 615–20. http://dx.doi.org/10.1016/s1474-6670(17)39819-1.

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Reichert, A. W., and H. Simon. "Design and Flow Field Calculations for Transonic and Supersonic Radial Inflow Turbine Guide Vanes." Journal of Turbomachinery 119, no. 1 (January 1, 1997): 103–13. http://dx.doi.org/10.1115/1.2840999.

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The design of radial inflow turbine guide vanes depends very much on the discharge conditions desired, especially if the choking mass flow is reached. Because of the choking mass flow condition and supersonic discharge Mach numbers, an inverse design procedure based on the method of characteristics is presented. Various designs corresponding to different discharge Mach numbers are shown. Viscous and inviscid flow field calculations for varying discharge conditions show the properties of the guide vanes at design and off-design conditions. In a previous paper (Reichert and Simon, 1994), an optimized design for transonic discharge conditions has been published. In the present paper, additional results concerning the optimum design are presented. For this optimum design an advantageous adjusting mechanism for a variable geometry guide vane has been developed. The effect of guide vane adjustment on the discharge conditions has been investigated using viscous flow field calculations.

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Song, Kang, Devesh Upadhyay, and Hui Xie. "An assessment of the impacts of low-pressure exhaust gas recirculation on the air path of a diesel engine equipped with electrically assisted turbochargers." International Journal of Engine Research 22, no. 1 (June 6, 2019): 3–21. http://dx.doi.org/10.1177/1468087419854294.

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The impact of assisted boosting technologies on the ability to maintain desired exhaust gas recirculation is investigated. Regenerative electrically assisted turbocharging is a promising technique for significantly reducing turbo lag. In addition to mitigating turbo lag, assisted boosting systems also allow fuel economy benefits through reduced pumping losses. Pumping loss reduction is achieved through optimally managing the exhaust pressure via vane position (for a variable geometry turbocharger) or waste gate position (for a waste-gated fixed geometry turbocharger). The consequent loss in exhaust turbine power, from reduced exhaust pressure, is supplemented by electrical assist power. Reduced exhaust pressure and a rapid increase in intake pressure results in a pressure differential across the high-pressure exhaust gas recirculation valve that may not support exhaust gas recirculation flow demands. Hence, a natural trade-off exists between the reduction of pumping loss and the ability to meet exhaust gas recirculation demand, as dictated by prescribed constraints on engine-out emissions. Low-pressure exhaust gas recirculation offers a potential solution that may allow the desired fuel economy improvements without sacrificing the desired exhaust gas recirculation fractions in the intake charge. In this article, we consider this problem and investigate the potential benefits of using low-pressure exhaust gas recirculation for assisted boosted systems.

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Journal articles on the topic 'Turbocharger with variable geometry vanes'

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