Experimental analysis and 1D simulation of an advanced hybrid boosting system for automotive applications in transient operation

2021 ◽  
pp. 146808742110601
Author(s):  
Silvia Marelli ◽  
Vittorio Usai
Keyword(s):  
Steady State ◽  
Transient Response ◽  
Simulation Software ◽  
Pollutant Emissions ◽  
Practical Significance ◽  
Steady State Condition ◽  
Automotive Engines ◽  
Electrically Assisted ◽  
Turbocharging System ◽  
The University

Due to the increasingly restrictive limits of pollutant emissions, electrification of automotive engines is now mandatory. For this reason, adopting hybrid boosting systems to improve brake specific fuel consumption and time-to-boost is becoming common practice. In this paper an advanced turbocharging system is analyzed, consisting in an electrically assisted radial compressor and a traditional turbocharger. As a first step, the steady-state performance of each component was measured at the University of Genoa test rig. Subsequently another experimental campaign was carried out to evaluate the transient response of the entire turbocharging system. Two different layouts were compared: upstream and downstream. In the upstream configuration the electrically assisted compressor was placed in front of the traditional turbocharger, in the downstream configuration the e-compressor was positioned after the traditional turbocharger. The two different coupling configurations, upstream and downstream, were then modeled in 1-D simulation software following the dimensions and characteristics of the experimental line from which the exploited data originates. The models were first validated by emulating the steady-state condition and subsequently the transient response was simulated and analyzed. Secondly, the transient response of the two layouts was compared, removing the constraints imposed by the experimental activity. The practical significance of the results is outlined, with reference to the transient response of the turbocharger. The adoption of the boosting system presented here allows a fast and stable transient response. Moreover, a reduction in the engine back pressure could be achieved through an optimization of the boosting system-engine matching calculation.

On the Transiant Response of Convective Extended Surface Heat Transfer: A New Approach

2006 ◽  
Author(s):  
P. Razelos ◽  
G. Michalakeas
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Transient Response ◽  
Surface Heat ◽  
Constant Thickness ◽  
Conduction Model ◽  
Steady State Condition ◽  
Surface Heat Transfer ◽  
Extended Surface ◽  
Extended Surfaces

This work is devoted to the study of the extended surfaces transient response. Although, the steady-state fin analysis has attracted considerable attention for a very long time, the interest in the transient response started in the last quarter of the past century. Several publications have appeared since, either analytical using the 1-D, conduction model, or experimental. Perusing the pertinent literature, however, we have observed that, in all previous published papers the authors treat the transient response of extended surfaces, or fins, like regular solids. However, fin endeavors rest on certain fundamental concepts, leading to some simplified assumptions, that we shall briefly discuss in the next section, which allows using the 1-D conduction model, and affect their steady-state operation. Therefore, the need for re-examining and revising the previously used methods becomes apparent. However, the authors are indebted to the pioneer workers on this topic that opened new avenues in the field of extended surface heat transfer. The aim of this work is to offer a different point of view to this problem, by introducing a new spatial coordinate system, and a new time scale. The solutions presented here, rest on the previously mentioned certain fundamental concepts developed recently. In the following we show step by step, how the existing pertinent equations and formulas of fins' transient response, are transformed to new simpler forms, expressed in terms of more appropriate dimensionless parameters, in accord with those appearing in recent publications. In the following, we confine to the analysis of constant thickness longitudinal and pin fins subject to specific1 boundary conditions. Each case is accompanied with an example that, for reasons of comparison are taken from the literature. We also discuss what is meant by "the time required for transient response to attain the steady-state condition."

scholarly journals Steady-state modeling and analysis of PWM current source drives

2021 ◽  
Author(s):  
Behrang Azizi Ghanad
Keyword(s):  
Steady State ◽  
Low Voltage ◽  
Mechanical Load ◽  
Short Circuit ◽  
Current Source ◽  
Parameter Tuning ◽  
Simulation Software ◽  
Drive System ◽  
State Condition ◽  
Steady State Condition

Current source converter based ac motor drives are increasingly used in medium voltage high power applications due to their simple converter topology, inherent four-quadrant operation, reliable short circuit protection and motor friendly waveforms. The behavior of the current source drive system in the steady state condition is studied in this thesis. The main objective of this investigation is to optimize the dc link inductance, which is one of the most expensive components of the drive system. The first research focus of this thesis is to model the current source drive system in steady state condition. Different parts of the drive system such as the induction motor, mechanical load and the complicated field oriented control (FOC) scheme are simplified for the steady state operation mode. This model has two main features: 1) substantially reduced simulation time, and 2) simplified control loop design without any control parameter tuning and control instability problem. Secondly, the characteristic of the dc link circuit is investigated using the developed steady state drive system model in MATLAB Simulink. The effect of the cd link inductance on the input LC resonant frequency is studied. The value of the dc current ripple is calculated under different conditions, and the effects of different system parameters on the ripple value is investigated. Furthermore, a user-friendly simulation software is developed for the dc choke optimization. Experiments are conducted on a low-voltage (30hp, 480V) current source drive system test setup at Rockwell Automation Canada, with which the developed simulation model is verified.

scholarly journals Steady-state modeling and analysis of PWM current source drives

2021 ◽  
Author(s):  
Behrang Azizi Ghanad
Keyword(s):  
Steady State ◽  
Low Voltage ◽  
Mechanical Load ◽  
Short Circuit ◽  
Current Source ◽  
Parameter Tuning ◽  
Simulation Software ◽  
Drive System ◽  
State Condition ◽  
Steady State Condition

Current source converter based ac motor drives are increasingly used in medium voltage high power applications due to their simple converter topology, inherent four-quadrant operation, reliable short circuit protection and motor friendly waveforms. The behavior of the current source drive system in the steady state condition is studied in this thesis. The main objective of this investigation is to optimize the dc link inductance, which is one of the most expensive components of the drive system. The first research focus of this thesis is to model the current source drive system in steady state condition. Different parts of the drive system such as the induction motor, mechanical load and the complicated field oriented control (FOC) scheme are simplified for the steady state operation mode. This model has two main features: 1) substantially reduced simulation time, and 2) simplified control loop design without any control parameter tuning and control instability problem. Secondly, the characteristic of the dc link circuit is investigated using the developed steady state drive system model in MATLAB Simulink. The effect of the cd link inductance on the input LC resonant frequency is studied. The value of the dc current ripple is calculated under different conditions, and the effects of different system parameters on the ripple value is investigated. Furthermore, a user-friendly simulation software is developed for the dc choke optimization. Experiments are conducted on a low-voltage (30hp, 480V) current source drive system test setup at Rockwell Automation Canada, with which the developed simulation model is verified.

An Improved Solution of the Transient Response of Convective Radial Fins

2007 ◽  
Author(s):  
S. Das ◽  
P. Razelos
Keyword(s):  
Steady State ◽  
Transient Response ◽  
Transcendental Equation ◽  
Point Of View ◽  
Constant Thickness ◽  
Past Century ◽  
Conduction Model ◽  
Steady State Condition ◽  
Extended Surface ◽  
Time Required

This work is devoted to the study of the convective radial fin’s transient response. Although, the steady-state fin analysis has attracted considerable attention for a very long time, the interest in the transient response started in the last quarter of the past century. Several publications have appeared since, either analytical, using the 1-D, and the 2-D conduction models, or experimental. Perusing the pertinent literature, we have observed that, in all previous published papers the authors treat the transient response of extended surfaces, or fins, like regular solids. However, fin endeavors rest on certain fundamental concepts, leading to some simplified assumptions, which we shall briefly discuss in the following sections, which allows using the 1-D conduction model, and their effect on steady-state operation. In addition, the bulk of the previous works refer to longitudinal and pin fins, while very few studies treat radial fins. Therefore, a re-examination and revision of the radial fin analysis is needed. The authors are indeed indebted to the pioneering work by previous researchers on this topic who have opened new avenues in the field of extended surface heat transfer. In this work, we present a new method, developed recently, which employs a new spatial coordinate system. It is also our intention to offer a different point of view to this problem, from those presented in the literature. The solutions presented here, rest on the previously mentioned certain fundamental concepts developed recently. In the following sections we show step by step, how the existing pertinent equations and formulae of the circular fins’ transient response, are transformed to new simpler forms, expressed in terms of certain more appropriate dimensionless parameters, from those presented in previously published papers. We confine our analysis to the constant thickness radial fins subject to specific boundary conditions. For reasons of comparison, the solution of a previous example cited in literature is presented. We also give a logical explanation as to what is meant by “the time required for transient response to attain the steady-state condition”. In addition, roots of the transcendental equation for the transient solution, that were not reported before are presented.

Performance Simulation of Marine Diesel Engines with SELENDIA

1999 ◽  
Vol 43 (04) ◽  
pp. 201-217
Author(s):  
P. Chesse ◽  
B. Inozu ◽  
P. Roy ◽  
X. Tauzia ◽  
J. F. Hetet
Keyword(s):  
Diesel Engine ◽  
New Orleans ◽  
Transient Response ◽  
Engine Performance ◽  
Pollutant Emissions ◽  
Simulation Code ◽  
Performance Simulation ◽  
Engine Simulation ◽  
Marine Diesel ◽  
The University

This paper describes a diesel engine simulation code, named SELENDIA, jointly developed by EcoleCentrale de Nantes, France, and the University of New Orleans. The adopted models for steady-state and transient response simulation are briefly introduced in addition to various validation results. The capabilities of the code are illustrated by a study regarding the transient response of a sequentially turbocharged marine diesel engine as well as the simulation of engine performance under extreme conditions and the investigation of engine pollutant emissions.

Steady-state and transient control strategies for a two-stage turbocharged diesel engine

2017 ◽  
Vol 232 (9) ◽  
pp. 1167-1179 ◽  
Author(s):  
Zhilong Hu ◽  
Kangyao Deng ◽  
Yi Cui ◽  
Xinxin Yang ◽  
Baochuan Zhang
Keyword(s):  
Steady State ◽  
Transient Response ◽  
Closed Loop ◽  
Control Strategies ◽  
Open Loop ◽  
Two Stage ◽  
Loop Control ◽  
Turbocharging System ◽  
Transient Control ◽  
Response Performance

Two-stage turbocharging technology is widely used to achieve higher engine power density and lower exhaust emissions. To solve a series of contradictions in matching, a regulated two-stage (RTS) turbocharging system is applied to reasonably control boost pressure. This paper investigated steady-state and transient control strategies for an RTS turbocharging system to achieve optimum fuel economy in steady-state conditions and better performance in transient conditions. The economic control strategies for steady-state operational conditions were based on an economic regulation law, which was established by a steady-state test of an engine with an RTS turbocharging system under all operating conditions. To optimize the transient performance, open-loop and closed-loop control systems (the latter with dynamic judgement) for the RTS system were designed and validated with experiments on a heavy-duty diesel engine. The experimental results demonstrated that the open-loop control strategy and the closed-loop strategy with dynamic judgement could improve the transient response performance. The optimum transient response performance was achieved by the closed-loop control system with dynamic judgement. Additionally, the combination of steady-state and transient control strategies could achieve the best fuel economy in steady-state conditions and good transient response performances.

A New Step in the Study of the History of the Russian Prosecutor’s Office

2019 ◽  
pp. 94-98
Keyword(s):  
Russian Federation ◽  
Russian Empire ◽  
Practical Significance ◽  
History Of ◽  
The Russian Federation ◽  
The Russian Empire ◽  
High Level ◽  
The University

The paper is a review on the textbook by A. V. Yeremin, «The History of the National Prosecutor’s office» and the anthology «The Prosecutor’s Office of the Russian Empire in the Documents of 1722–1917» (authors: V. V. Lavrov, A. V. Eremin, edited by N. M. Ivanov) published at the St. Petersburg Law Institute (branch) of the University of the Prosecutor’s office of the Russian Federation in 2018. The reviewers emphasize the high relevance and high level of research, their theoretical and practical significance. The textbook and the anthology will help the students increase their legal awareness, expand their horizons.

scholarly journals Numerical Evaluation of a HVAC System Based on a High-Performance Heat Transfer Fluid

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3298
Author(s):  
Gianpiero Colangelo ◽  
Brenda Raho ◽  
Marco Milanese ◽  
Arturo de Risi
Keyword(s):  
Heat Transfer ◽  
High Performance ◽  
Cooling System ◽  
Electrical Energy ◽  
Simulation Software ◽  
Heat Transfer Fluid ◽  
Hvac System ◽  
Dynamic Simulations ◽  
Heating And Cooling ◽  
The University

Nanofluids have great potential to improve the heat transfer properties of liquids, as demonstrated by recent studies. This paper presents a novel idea of utilizing nanofluid. It analyzes the performance of a HVAC (Heating Ventilation Air Conditioning) system using a high-performance heat transfer fluid (water-glycol nanofluid with nanoparticles of Al2O3), in the university campus of Lecce, Italy. The work describes the dynamic model of the building and its heating and cooling system, realized through the simulation software TRNSYS 17. The use of heat transfer fluid inseminated by nanoparticles in a real HVAC system is an innovative application that is difficult to find in the scientific literature so far. This work focuses on comparing the efficiency of the system working with a traditional water-glycol mixture with the same system that uses Al2O3-nanofluid. The results obtained by means of the dynamic simulations have confirmed what theoretically assumed, indicating the working conditions of the HVAC system that lead to lower operating costs and higher COP and EER, guaranteeing the optimal conditions of thermo-hygrometric comfort inside the building. Finally, the results showed that the use of a nanofluid based on water-glycol mixture and alumina increases the efficiency about 10% and at the same time reduces the electrical energy consumption of the HVAC system.

scholarly journals Computational Performance of Disparate Lattice Boltzmann Scenarios under Unsteady Thermal Convection Flow and Heat Transfer Simulation

Computation ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 65
Author(s):  
Aditya Dewanto Hartono ◽  
Kyuro Sasaki ◽  
Yuichi Sugai ◽  
Ronald Nguele
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Natural Convection ◽  
Lattice Boltzmann ◽  
Numerical Results ◽  
Convection And Heat Transfer ◽  
Steady State Condition ◽  
Physical Systems ◽  
Flow And Heat Transfer ◽  
Computational Performance

The present work highlights the capacity of disparate lattice Boltzmann strategies in simulating natural convection and heat transfer phenomena during the unsteady period of the flow. Within the framework of Bhatnagar-Gross-Krook collision operator, diverse lattice Boltzmann schemes emerged from two different embodiments of discrete Boltzmann expression and three distinct forcing models. Subsequently, computational performance of disparate lattice Boltzmann strategies was tested upon two different thermo-hydrodynamics configurations, namely the natural convection in a differentially-heated cavity and the Rayleigh-Bènard convection. For the purposes of exhibition and validation, the steady-state conditions of both physical systems were compared with the established numerical results from the classical computational techniques. Excellent agreements were observed for both thermo-hydrodynamics cases. Numerical results of both physical systems demonstrate the existence of considerable discrepancy in the computational characteristics of different lattice Boltzmann strategies during the unsteady period of the simulation. The corresponding disparity diminished gradually as the simulation proceeded towards a steady-state condition, where the computational profiles became almost equivalent. Variation in the discrete lattice Boltzmann expressions was identified as the primary factor that engenders the prevailed heterogeneity in the computational behaviour. Meanwhile, the contribution of distinct forcing models to the emergence of such diversity was found to be inconsequential. The findings of the present study contribute to the ventures to alleviate contemporary issues regarding proper selection of lattice Boltzmann schemes in modelling fluid flow and heat transfer phenomena.

Comparison of Auditory Steady-State Response and Auditory Brainstem Response Thresholds in Children

2002 ◽  
Vol 13 (05) ◽  
pp. 227-235 ◽  
Author(s):  
Kathy R. Vander Werff ◽  
Carolyn J. Brown ◽  
Barbara A. Gienapp ◽  
Kelly M. Schmidt Clay
Keyword(s):  
Steady State ◽  
Auditory Brainstem Response ◽  
Auditory Brainstem ◽  
Strong Correlations ◽  
University Of Iowa ◽  
Brainstem Response ◽  
Steady State Responses ◽  
Children With Hearing Loss ◽  
Auditory Steady State Responses ◽  
The University

Recently, auditory steady-state responses (ASSRs) have been proposed as an alternative to the auditory brainstem response (ABR) for threshold estimation. The goal of this study was to investigate the degree to which ASSR thresholds correlate with ABR thresholds for a group of sedated children with a range of hearing losses. Thirty-two children from the University of Iowa Hospitals and Clinics ranging in age from 2 months to 3 years and presenting with a range of ABR thresholds participated. Strong correlations were found between the 2000-Hz ASSR thresholds and click ABR thresholds (r = .96), the average of the 2000- and 4000-Hz ASSR thresholds and click ABR thresholds (r = .97), and the 500-Hz ASSR and 500-Hz toneburst ABR thresholds (r = .86). Additionally, it was possible to measure ASSR thresholds for several children with hearing loss that was great enough to result in no ABR at the limits of the equipment. The results of this study indicate that the ASSR may provide a reasonable alternative to the ABR for estimating audiometric thresholds in very young children.

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