An applied thermodynamic method for correction of TDC in the indicator diagram and its experimental confirmation

Chen, Hanbao; Zhang, Yusheng; Chen, Lingen

doi:10.1016/j.applthermaleng.2004.07.016

Cited by 19 publications

(22 citation statements)

References 3 publications

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“…Ref. [22] presented a method based on rate of heat release calculation, which can approach accuracy of the polytropic exponent method. It needs to be mentioned that pressure offset needs to be determined accurately to approach errors listed previously in this paragraph.…”

Section: Introductionmentioning

confidence: 99%

A New Method for Simultaneous Determination of the TDC Offset and the Pressure Offset in Fired Cylinders of an Internal Combustion Engine

et al. 2017

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An innovative computationally efficient method for the simultaneous determination of top dead centre (TDC) offset and pressure offset is presented. It is based on characteristic deviations of the rate of heat release (ROHR) that are specific for both offsets in compression phase and expansion phase after the end of combustion. These characteristic deviations of the ROHR are derived from first principles and they were also confirmed through manual shifts of the pressure trace. The ROHR is calculated based on the first law of thermodynamics using an in-cylinder pressure trace, engine geometrical parameters and operating point specific parameters. The method can be applied in off-line analyses using an averaged pressure trace or in on-line analyses using a single pressure trace. In both application areas the method simultaneously determines the TDC position and the pressure offset within a single processing of the pressure trace, whereas a second refinement step can be performed for obtaining more accurate results as correction factors are determined more accurately using nearly converged input data. Innovative analytic basis of the method allows for significant reduction of the computational times compared to the existing methods for the simultaneous determination of TDC offset and pressure offset in fired conditions. The method was validated on a heavy-duty and a light-duty diesel engine.

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Section: Introductionmentioning

confidence: 99%

A New Method for Simultaneous Determination of the TDC Offset and the Pressure Offset in Fired Cylinders of an Internal Combustion Engine

et al. 2017

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“…The identification errors of sonic conductance of the new method developed in [5] are stated to by less than 3%, and the identification errors of critical pressure ratio of the new algorithm given by [5] are less than 15%. In the research of Chang et al [6], a thermodynamic method of top dead center (TDC) correction in the indicator diagram of diesel engines is presented. The method outlined in [6] is based on the corresponding relationship between the curve for the heat released and the computed polytropic exponent.…”

Section: Figure 2 P-v Diagram Of Sco2 Expansion Processmentioning

confidence: 99%

“…In the research of Chang et al [6], a thermodynamic method of top dead center (TDC) correction in the indicator diagram of diesel engines is presented. The method outlined in [6] is based on the corresponding relationship between the curve for the heat released and the computed polytropic exponent. The experiments of [6] demonstrate that this method can make the real-time correction of TDC for the Diesel engines.…”

Section: Figure 2 P-v Diagram Of Sco2 Expansion Processmentioning

confidence: 99%

“…The method outlined in [6] is based on the corresponding relationship between the curve for the heat released and the computed polytropic exponent. The experiments of [6] demonstrate that this method can make the real-time correction of TDC for the Diesel engines. From this literature review, we see that the use of the polytropic exponent in fundamental thermodynamic research is still warranted and justified, and its determination is usually typified using a combination of complex numerical modeling in conjunction with the conduction of experiments.…”

Section: Figure 2 P-v Diagram Of Sco2 Expansion Processmentioning

confidence: 99%

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Method of Determining a Nominal Index Value for the Polytropic Expansion Process of Supercritical Carbon Dioxide in Piston-Cylinder Devices

Anderson

2014

Int. J. Thermo

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The polytropic process is a widely used pressure model for predicting the nature of pressure and volume states in expansion and compression systems. The two variable nature of this model typically leads to an open ended approach with heavy reliance on mechanism evaluation and potential extended design iterations in the prototyping phase. Through a fundamental examination of the polytropic derivation from the energy transfer ratio assumption, in conjunction with repeated application of elementary thermodynamic principles, including First Law analysis, moving boundary work, and substance property evaluation, a solution to a refined nominal polytropic index can be found. The derivation can provide valuable insight to the polytropic process itself and address the issue of bounding a complex system with a reasonable choice of theoretical system input. With the aid of the method outlined in this paper, researchers will be enabled with a tool to better predict the polytropic expansion coefficient which finds widespread use in thermodynamic modeling and analysis. To this end, the method is used herein to predict a polytropic index of n = 1.306 and k = 1.615 for the specific heat ratio for a SCO2 expansion engine operating between 20 MPa and 9.2 MPa.

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“…Reference [9] derives some necessary conditions for the polytropic exponent that can be used to correct the TDC position. The method provides a TDC correction that varies by approximately 0.5…”

Section: Introductionmentioning

confidence: 99%

TDC Offset Estimation from Motored Cylinder Pressure Data based on Heat Release Shaping

Tunestål

2011

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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Résumé -Estimation du décalage de PMH à partir de données de pression de cylindre moteur basées sur la conformation de libération de chaleur -La détermination du décalage de Point Mort Haut (PMH) correct d'un moteur à combustion interne est plus difficile qu'il n'y paraît. Cette étude introduit une nouvelle méthode destinée à déterminer le décalage de PMH sur la base de la simple supposition que la puissance de perte de chaleur à travers les parois de la chambre de combustion soit constante pour des cycles moteur selon un intervalle d'angle de bras de manivelle étroit autour du PMH. La méthode proposée utilise une optimisation des moindres carrés non linéaire pour déterminer la combinaison de rapport de chaleur spécifique et de décalage de PMH qui rend la puissance de perte de chaleur aussi constante que possible. Un sous-problème important consiste à déterminer la localisation de pression de pic avec une haute précision. L'application d'une série de Fourier du troisième ordre à la pression de cylindre moteur permet l'estimation du maximum de pression moyennant un écart-type de 0,005• d'angle de bras de manivelle (AM) et elle peut être également utilisée à la place de la pression mesurée afin de réduire l'incertitude de l'estimation du PMH d'environ 50 %. L'écart-type d'une estimation de PMH de cycle unique est approximativement de 0,025• d'AM lors de l'utilisation d'une résolution de bras de manivelle de 0,2• d'AM pour les mesures. L'erreur systématique de l'estimation de PMH se situe dans la plage allant de 0 à 0,02• d'AM par comparaison à la fois avec les mesures réalisées au moyen d'un détecteur de PMH et avec des cycles moteur simulés. La méthode peut être utilisée à la fois à des fins d'étalonnage et de diagnostics à bord, par exemple pendant un démarrage, une coupure de carburant ou un arrêt du moteur. La série de Fourier du troisième ordre appliquée s'accompagne d'une pénalisation de calcul significative mais, puisqu'elle n'est appliquée que de façon très intermittente, ceci ne doit pas poser un problème sérieux. Abstract -TDC Offset Estimation from Motored Cylinder Pressure Data based on Heat Release Shaping -Finding the correct Top Dead Center (TDC) offset for an internal combustion engine is harder than it seems. This study introduces a novel method to find the TDC offset based on the simple assumption that the heat loss power through the combustion chamber walls is constant for motored cycles in a narrow

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An applied thermodynamic method for correction of TDC in the indicator diagram and its experimental confirmation

Cited by 19 publications

References 3 publications

A New Method for Simultaneous Determination of the TDC Offset and the Pressure Offset in Fired Cylinders of an Internal Combustion Engine

A New Method for Simultaneous Determination of the TDC Offset and the Pressure Offset in Fired Cylinders of an Internal Combustion Engine

Method of Determining a Nominal Index Value for the Polytropic Expansion Process of Supercritical Carbon Dioxide in Piston-Cylinder Devices

TDC Offset Estimation from Motored Cylinder Pressure Data based on Heat Release Shaping

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