Numerical and Experimental Investigation of the Thermal Behavior of a Complete Exhaust System

Fortunato, Francesco; Caprio, Marco; Oliva, Paolo; D'Aniello, Giovanni; Pantaleone, Piero; Andreozzi, Assunta; Manca, Oronzio

doi:10.4271/2007-01-1094

Cited by 10 publications

(4 citation statements)

References 11 publications

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“…Furthermore, thermocouples are more suitable for possible future adoption in an engine monitoring system, thanks to their easier synchronization with other sensors, their robustness, and their cheapness. Nevertheless, the correct use of these sensors is not trivial, and some aspects must be evaluated carefully, as many studies demonstrated [41][42][43][44]. Firstly, the right thermocouple-type must be chosen on the basis of the expected absolute value and variation range of the temperature to be measured.…”

mentioning

confidence: 99%

“…The exhaust gas mass flow and the inlet gas temperature influence the amount of discharge thermal power, the fluid dynamics, and the boundary layers inside the pipes influence the heat transfer [43,45,49]; • Thermal contact resistance might affect the heat exchange between different components and between the thermocouples and the metal surfaces where they lay. Once these parameters have been individuated, viable values (reference, upper, lower) were found for each of them, obtaining a set of values used to generate a first simulation plan, i.e., as a starting point for the CFD-FVM model tuning procedure:…”

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confidence: 99%

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Torque Prediction Model of a CI Engine for Agricultural Purposes Based on Exhaust Gas Temperatures and CFD-FVM Methodologies Validated with Experimental Tests

et al. 2021

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A truly universal system to optimize consumptions, monitor operation and predict maintenance interventions for internal combustion engines must be independent of onboard systems, if present. One of the least invasive methods of detecting engine performance involves the measurement of the exhaust gas temperature (EGT), which can be related to the instant torque through thermodynamic relations. The practical implementation of such a system requires great care since its torque-predictive capabilities are strongly influenced by the position chosen for the temperature-detection point(s) along the exhaust line, specific for each engine, the type of installation for the thermocouples, and the thermal characteristics of the interposed materials. After performing some preliminary tests at the dynamometric brake on a compression-ignition engine for agricultural purposes equipped with three thermocouples at different points in the exhaust duct, a novel procedure was developed to: (1) tune a CFD-FVM-model of the exhaust pipe and determine many unknown thermodynamic parameters concerning the engine (including the real EGT at the exhaust valve outlet in some engine operative conditions), (2) use the CFD-FVM results to considerably increase the predictive capability of an indirect torque-detection strategy based on the EGT. The joint use of the CFD-FVM software, Response Surface Method, and specific optimization algorithms was fundamental to these aims and granted the experimenters a full mastery of systems’ non-linearity and a maximum relative error on the torque estimations of 2.9%.

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confidence: 99%

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confidence: 99%

Torque Prediction Model of a CI Engine for Agricultural Purposes Based on Exhaust Gas Temperatures and CFD-FVM Methodologies Validated with Experimental Tests

et al. 2021

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“…This is the reason why a data acquisition system placed on these machines would be of great importance [5]. In this context, the exhaust gas temperature (EGT) is one of the most meaningful parameters that can be monitored, as it can provide information about the torque, combustion quality, pollutants [6][7][8][9]. The correlation between the EGT and the torque is proven [10][11][12][13] with the most approximated equation that gives a linear correlation between these two quantities.…”

Section: Introductionmentioning

confidence: 99%

Experimental problem of indirectly detecting engine torque delivered by agricultural machines through exhaust gas temperature

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Selmo

Renzi

et al. 2021

20th International Scientific Conference Engineering for Rural Development Proceedings

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Measuring the performance of the compression-ignition internal combustion engine of agricultural machines (in particular, the torque delivered instantaneously) is an essential requirement for monitoring: (a) the exploitation of the engine mechanical-energy potential (in terms of generated torque) and (b) its correct operation (in terms of global efficiency, fuel consumption and possible ageing). Due to the many important technical and economic implications, the instant acquisition of the engine torque is therefore a critical point in any operational monitoring system, as well as in predictive maintenance models. Torque measurement is by no means a simple task, especially in old agricultural machines lacking of default data acquisition devices/on-board electronics, and many critical issues arise from the fact that it involves rotating components (shafts), which are often difficult to be accessed. For this reason, an indirect torque measurement methodology, based on a predictive model relying on the exhaust gas temperature, is preferable. An accurate measurement of temperature data is of primary importance to precisely calculate the torque, which means performing an accurate thermocouple choice, placement, and data elaboration. This is made even more challenging by the fact that the temperature of the exhaust gas is often in a transient state due to variable engine regime necessary for machine operation. The study presented here illustrates some considerations about the trend and the equation of the experimental measurements of the exhaust gas temperature, considering three different positions for the thermocouples on the exhaust line, and proposes an optimal technical solution in terms of sensitivity and promptness of response.

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“…Three different approaches were used in Fortunato et al [10] to simulate the exhaust and underbody of the car: 1D, 3D finite elements and 3D complete thermo-fluid-dynamics. Both 3D models allowed to detect the most critical points in terms of higher temperatures…”

Section: Introductionmentioning

confidence: 99%

Developing Computational Fluid Dynamics (CFD) Models to Evaluate Available Energy in Exhaust Systems of Diesel Light-Duty Vehicles

et al. 2017

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Around a third of the energy input in an automotive engine is wasted through the exhaust system. Since numerous technologies to harvest energy from exhaust gases are accessible, it is of great interest to find time-and cost-efficient methods to evaluate available thermal energy under different engine conditions. Computational fluid dynamics (CFD) is becoming a very valuable tool for numerical predictions of exhaust flows. In this work, a methodology to build a simple three-dimensional (3D) model of the exhaust system of automotive internal combustion engines (ICE) was developed. Experimental data of exhaust gas in the most used part of the engine map in passenger diesel vehicles were employed as input for calculations. Sensitivity analyses of different numeric schemes have been conducted in order to attain accurate results. The model built allows for obtaining details on temperature and pressure fields along the exhaust system, and for complementing the experimental results for a better understanding of the flow phenomena and heat transfer through the system for further energy recovery devices.

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Numerical and Experimental Investigation of the Thermal Behavior of a Complete Exhaust System

Cited by 10 publications

References 11 publications

Torque Prediction Model of a CI Engine for Agricultural Purposes Based on Exhaust Gas Temperatures and CFD-FVM Methodologies Validated with Experimental Tests

Torque Prediction Model of a CI Engine for Agricultural Purposes Based on Exhaust Gas Temperatures and CFD-FVM Methodologies Validated with Experimental Tests

Experimental problem of indirectly detecting engine torque delivered by agricultural machines through exhaust gas temperature

Developing Computational Fluid Dynamics (CFD) Models to Evaluate Available Energy in Exhaust Systems of Diesel Light-Duty Vehicles

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