A Methodology for Measuring Turbocharger Adiabatic Maps in a Gas-Stand and Its Usage for Calibrating Control Oriented and One-Dimensional Models at Early ICE Design Stages

Abstract In this work, a methodology is proposed to standardize turbochargers testing based on measuring the maps twice: in close to adiabatic and in diathermal conditions. Along the paper, it is discussed with special detail the impact of the procedure followed to achieve said quasi-adiabatic conditions in both the energy balance of the turbocharger and the testing complexity. As a conclusion, the paper proposes a methodology which combines quasi-adiabatic tests (cold and hot gas flow) with diathermal tests (hot gas flow) in order to extract from a turbocharger gas-stand all information needed by engine designers interested in controlling or one-dimensional-modeling the internal combustion engine (ICE). The methodology is completed with a guide for calibrating said control-oriented turbocharger models in order to separate aerodynamic efficiency (adiabatic) from heat transfer (HT) losses and from friction losses in the analysis of the turbocharger performance. The outsourced calibration of the turbocharger model allows avoiding uncertainties in the global ICE model calibration, what is very interesting for turbochargers benchmarking at early ICE-turbo matching stages or for global system analysis at early control design stages.

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A one-dimensional modeling study on the effect of advanced insulation coatings on internal combustion engine efficiency

International Journal of Engine Research ◽

10.1177/1468087420921584 ◽

2020 ◽

pp. 146808742092158

Author(s):

Alberto Broatch ◽

Pablo Olmeda ◽

Xandra Margot ◽

Josep Gomez-Soriano

Keyword(s):

Heat Transfer ◽

Combustion Engine ◽

Heat Transfer Model ◽

Transfer Model ◽

Insulation Material ◽

One Dimensional ◽

Engine Efficiency ◽

Dimensional Modeling ◽

The One ◽

The Impact

This article presents a study of the impact on engine efficiency of the heat loss reduction due to in-cylinder coating insulation. A numerical methodology based on one-dimensional heat transfer model is developed. Since there is no analytic solution for engines, the one-dimensional model was validated with the results of a simple “equivalent” problem, and then applied to different engine boundary conditions. Later on, the analysis of the effect of different coating properties on the heat transfer using the simplified one-dimensional heat transfer model is performed. After that, the model is coupled with a complete virtual engine that includes both thermodynamic and thermal modeling. Next, the thermal flows across the cylinder parts coated with the insulation material (piston and cylinder head) are predicted and the effect of the coating on engine indicated efficiency is analyzed in detail. The results show the gain limits, in terms of engine efficiency, that may be obtained with advanced coating solutions.

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A Methodology for Measuring Turbocharger Adiabatic Maps in a Gas-Stand and its Usage for Calibrating Control Oriented and 1D Models at Early ICE Design Stages

ASME 2019 Internal Combustion Engine Division Fall Technical Conference ◽

10.1115/icef2019-7125 ◽

2019 ◽

Cited By ~ 1

Author(s):

José Ramón Serrano ◽

Francisco José Arnau ◽

Luis Miguel García-Cuevas ◽

Alejandro Gómez-Vilanova ◽

Stephane Guilain ◽

...

Keyword(s):

Heat Transfer ◽

Internal Combustion Engines ◽

Gas Flow ◽

System Analysis ◽

Pressure Ratio ◽

Inlet Temperature ◽

Boost Pressure ◽

Gas Temperature ◽

Hot Gas ◽

The Impact

Abstract Turbocharged engines are the standard architecture for designing efficient spark ignition and compression ignition reciprocating internal combustion engines (ICE). Turbochargers characterization and modeling are basic tasks for the analysis and prediction of the whole engine system performance and this information is needed in quite early stages of the engine design. Turbocharger characteristics (efficiency, pressure ratio, mass flow rates...) traditionally rely in maps of pseudo non-dimensional variables called reduced variables. These maps must be used by reciprocating ICE designer and modeler not only for benchmarking of the turbocharger, but for a multiplicity of purposes, i.e: assessing engine back-pressure, boost pressure, load transient response, after-treatment inlet temperature, intercooler inlet temperature, low pressure EGR temperature, ... Maps of reduced variables are measured in gas-stands with steady flow but non-standardized fluids conditioning; neither temperatures nor flows. In concrete: turbine inlet gas temperature; lubrication-oil flow and temperature; water-cooling flow and turbo-machinery external heat transfer are non-standardized variables which have a big impact in assessing said multiplicity of purposes. Moreover, adiabatic efficiency, heat losses and friction losses are important data, hidden in the maps of reduced variables, which depend on the testing conditions as much as on the auxiliary fluids temperature and flow rate. In this work it is proposed a methodology to standardize turbochargers testing based in measuring the maps twice: in close to adiabatic and in diathermal conditions. Along the paper it is discussed with special detail the impact of the procedure followed to achieve said quasi-adiabatic conditions in both the energy balance of the turbocharger and the testing complexity. As a conclusion, the paper proposes a methodology which combines quasi-adiabatic tests (cold and hot gas flow) with diathermal tests (hot gas flow) in order to extract from a turbocharger gas-stand all information needed by engine designers interested in controlling or 1D-modelling the ICE. The methodology is completed with a guide for calibrating said control-oriented turbocharger models in order to separate aerodynamic efficiency (adiabatic) from heat transfer losses and from friction losses in the analysis of the turbocharger performance. The outsourced calibration of the turbocharger model allows avoiding uncertainties in the global ICE model calibration, what is very interesting for turbochargers benchmarking at early ICE-turbo matching stages or for global system analysis at early control design stages.

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Integrated modelling of internal combustion engine intake and exhaust systems

Proceedings of the Institution of Mechanical Engineers Part A Journal of Power and Energy ◽

10.1243/0957650011538622 ◽

2001 ◽

Vol 215 (4) ◽

pp. 495-506 ◽

Cited By ~ 6

Author(s):

O Chiavola

Keyword(s):

Internal Combustion Engines ◽

Gas Flow ◽

Complex Geometry ◽

Combustion Engine ◽

Internal Combustion ◽

Integrated Modelling ◽

Dimensional Model ◽

Three Dimensional Model ◽

One Dimensional ◽

Exhaust Systems

This paper presents a new method to analyse the unsteady gas flow in both intake and exhaust systems of internal combustion engines. Such a method is based on the simultaneous use of a one-dimensional model applied to describe the phenomena in ducts, together with a lumped parameter scheme to investigate the cylinder or other volume behaviour, coupled with a three-dimensional model, able to guarantee detailed information on flow behaviour in complex geometry, retaining the advantages of all methods, accuracy as well as fast processing and high flow pattern resolution. The description of the one-dimensional model developed with an example of its application is presented. The integrated approach with the coupling procedure is then described. Finally the results of a multicylinder exhaust system simulation are illustrated.

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Influence of the combustion chamber geometry on the scavenging of a four-stroke internal-combustion engine during the valve overlap period

Proceedings of the Institution of Mechanical Engineers Part D Journal of Automobile Engineering ◽

10.1177/0954407015624335 ◽

2016 ◽

Vol 230 (14) ◽

pp. 1873-1890

Author(s):

Nicolas-Ivan Hatat ◽

David Chalet ◽

François Lormier ◽

Pascal Chessé

Keyword(s):

Internal Combustion Engine ◽

Combustion Engine ◽

Internal Combustion ◽

One Dimensional ◽

Digital Testing ◽

The One ◽

Small Engines ◽

Variable Valve ◽

Valve Overlap ◽

The Impact

The performance of an internal-combustion engine is directly related to the fuel quantity that can react with the oxygen in the air during the exothermic oxidation step, also called combustion. Thus, the amount of fuel introduced is intrinsically linked to the air volume that can be admitted into the cylinder (air filling of the cylinder). Hence keeping the air in the cylinder is one of the most important concepts to predict in simulations. Nevertheless, the phenomenon of air filling depends on many parameters. Also, the discharge coefficients, and the impact of the piston presence near the valves on the flow, during valve overlap are investigated. For this, a digital flow bench is constructed to reproduce a series of tests carried out on a flow test bench functioning as a result of the reduction in the pressure. In this paper, the engine studied is a 125 cm3 single-cylinder four-stroke atmospheric type with two valves. Thus, the idea of this paper is to treat the case of engines with large valve overlaps as small engines or engines with variable valve timing. First, traditional tests through a single valve are performed. The forward and reverse directions are systematically tested to ensure proper operation of the digital testing, and to determine the differences between tests and simulations in the case of conventional configurations. Then, the flow through the entire cylinder head, i.e. the intake valve–cylinder with piston–exhaust valve system, is tested and studied. The aim is to compare the results obtained by the tests and the simulations during the valve overlap period. Significant differences were highlighted between the rates measured in one-dimensional simulations and in the tests. It was noteworthy that the one-dimensional code overestimated the mass passing through the system during valve overlap by about one fifth of the estimated mass passing through the system from the results obtained with the test rig.

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Heat Transfer Correction Methods for Turbocharger Performance Measurements

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4034234 ◽

2016 ◽

Vol 139 (2) ◽

Cited By ~ 6

Author(s):

Mario Schinnerl ◽

Joerg Seume ◽

Jan Ehrhard ◽

Mathias Bogner

Keyword(s):

Heat Transfer ◽

Predictive Accuracy ◽

Combustion Engine ◽

Transfer Model ◽

Performance Measurements ◽

One Dimensional ◽

Matching Process ◽

High Speeds ◽

Work Done ◽

The Impact

Turbocharger performance maps used for the matching process with a combustion engine are measured on test benches which do not exhibit the same boundary conditions as the engine. However, these maps are used in engine simulations, ignoring that the compressor and turbine aerodynamic performance is rated on the basis of quantities which were measured at positions which do not coincide with the respective system boundaries of the turbomachinery. In the operating range of low to mid engine speeds, the ratio between the heat flux and the work done by the turbine and the compressor is much greater than at high speeds where heat transfer phenomena on the compressor side can usually be neglected. Heat losses on the turbine side must be taken into account even at higher shaft speeds when dealing with isentropic turbine efficiencies. Based on an extensive experimental investigation, a one-dimensional heat transfer model is developed. The compressor and turbine side are treated individually and divided into sections of inlet, wheel, outlet, diffuser, and volute. The model demonstrates the capability to properly account for the impact of heat transfer, and thereby improves the predictive accuracy of temperatures relevant for the matching process.

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

International Journal of Engine Research ◽

10.1177/1468087417752525 ◽

2018 ◽

Vol 20 (3) ◽

pp. 327-349 ◽

Cited By ~ 5

Author(s):

Federico Piscaglia ◽

Angelo Onorati ◽

Silvia Marelli ◽

Massimo Capobianco

Keyword(s):

Unsteady Flow ◽

Combustion Engine ◽

Fluid Dynamic ◽

Mass Storage ◽

Dimensional Model ◽

One Dimensional ◽

Dimensional Modeling ◽

The One ◽

System Volume ◽

Unsteady Behavior

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

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Heat Transfer Correction Methods for Turbocharger Performance Measurements

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

10.1115/gt2016-56770 ◽

2016 ◽

Cited By ~ 1

Author(s):

Mario Schinnerl ◽

Joerg Seume ◽

Jan Ehrhard ◽

Mathias Bogner

Keyword(s):

Heat Transfer ◽

Predictive Accuracy ◽

Combustion Engine ◽

Transfer Model ◽

Performance Measurements ◽

One Dimensional ◽

Matching Process ◽

High Speeds ◽

Work Done ◽

The Impact

Turbocharger performance maps used for the matching process with a combustion engine are measured on test benches which do not exhibit the same boundary conditions as the engine. However, these maps are used in engine simulations, ignoring that the compressor and turbine aerodynamic performance is rated on the basis of quantities which were measured at positions which do not coincide with the respective system boundaries of the turbomachinery. In the operating range of low to mid engine speeds, the ratio between the heat flux and the work done by the turbine and the compressor is much greater than at high speeds where heat transfer phenomena on the compressor side can usually be neglected. Heat losses on the turbine side must be taken into account even at higher shaft speeds when dealing with isentropic turbine efficiencies. Based on an extensive experimental investigation a one-dimensional heat transfer model is developed. The compressor and turbine side are treated individually and divided into sections of inlet, wheel, outlet, diffuser and volute. The model demonstrates the capability to properly account for the impact of heat transfer and thereby improves the predictive accuracy of temperatures relevant for the matching process.

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Fundamental Characterization of Turbocharger Turbine Unsteady Flow Behavior

Volume 6: Turbo Expo 2007, Parts A and B ◽

10.1115/gt2007-28317 ◽

2007 ◽

Cited By ~ 8

Author(s):

Aaron Costall ◽

Ricardo F. Martinez-Botas

Keyword(s):

Fourier Series ◽

Gas Flow ◽

Combustion Engine ◽

Flow Behavior ◽

Wave Action ◽

Exhaust Gas ◽

Engine Exhaust ◽

One Dimensional ◽

Gas Dynamic ◽

Unsteady Effects

Fluid flow in the volute of a turbocharger turbine can be decidedly unsteady due to the pulsating nature of the exhaust gas in the manifolds of an internal combustion engine. Despite this it is conventional to use a quasi-steady or “filling and emptying” technique to model the turbine in one-dimensional turbocharged engine simulations. Depending on the inherent level of unsteadiness, this approach may be insufficient to capture the true turbine operation since neither method is able to resolve unsteady effects due to the presence of any wave action in the flow. Building on previously reported work, this paper aims to establish a measure of unsteadiness that takes account of the attributes of engine exhaust gas flow that give rise to gas dynamic unsteadiness. This characterization is achieved by decomposing the pulse into its constituent frequencies using Fourier analysis. A one-dimensional wave action code, featuring a bespoke boundary condition that permits application of a pressure pulse in Fourier series form, is used to investigate the effect of the contributing variables for some simplified cases. This allows the construction of the correct form of dimensionless parameter. Finally, the new dimensionless measures, the Fourier series Strouhal and acoustic Strouhal numbers (FSt and FaSt respectively), are evaluated at different test conditions to establish criteria for the transition from a filling and emptying mode to gas dynamic operation. The analysis suggests limiting values of FSt≤0.15, and FaSt≤0.02, to be used as an approximate guide for turbine model selection.

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