It is known to internal combustion researcher that the correct determination of the crank position when the piston is at Top Dead Centre (TDC) is very important, since an error of 1 crank angle degree (CAD) can cause up to a 10% evaluation error on indicated mean effective pressure (IMEP) and a 25% error on the heat released by the combustion: the TDC position should be then known within a precision of 0.1 CAD. This task can be accomplished by means of a dedicated capacitive sensor, which allows a measurement within the required 0.1 degrees precision. Such a sensor has a substantial cost and its use is not really fast; a different approach can be followed using a thermodynamic method, whose input is the pressure curve sampled during the compression and expansion strokes of a “motored” (i.e. without combustion) cylinder.In this work the authors compare an original thermodynamic method with other ones available in literature, by means of both experimental and simulated pressure curves. A zero dimensional thermodynamic model was employed to obtain an extensive collection of numeric pressure curves by changing engine geometry (e.g. compression ratios from 10 to 20 were adopted), operative conditions and wall heat transfer laws. The in-cylinder mass leakage has been taken into account in the model.Moreover, in order to assess the reliability and robustness of each method, the typical measurement errors and disturbances related to indicating analysis have been taken into account. The capability of the investigated methods to provide the correct TDC position in presence of the above mentioned errors has been evaluated.

PIPITONE E, BECCARI A, BECCARI S (2008). Reliable TDC position determination: a comparison of different thermodynamic methods through experimental data and simulations. SAE TECHNICAL PAPER, 1-11 [10.4271/2008-36-0059].

Reliable TDC position determination: a comparison of different thermodynamic methods through experimental data and simulations

PIPITONE, Emiliano;BECCARI, Alberto;BECCARI, Stefano
2008-01-01

Abstract

It is known to internal combustion researcher that the correct determination of the crank position when the piston is at Top Dead Centre (TDC) is very important, since an error of 1 crank angle degree (CAD) can cause up to a 10% evaluation error on indicated mean effective pressure (IMEP) and a 25% error on the heat released by the combustion: the TDC position should be then known within a precision of 0.1 CAD. This task can be accomplished by means of a dedicated capacitive sensor, which allows a measurement within the required 0.1 degrees precision. Such a sensor has a substantial cost and its use is not really fast; a different approach can be followed using a thermodynamic method, whose input is the pressure curve sampled during the compression and expansion strokes of a “motored” (i.e. without combustion) cylinder.In this work the authors compare an original thermodynamic method with other ones available in literature, by means of both experimental and simulated pressure curves. A zero dimensional thermodynamic model was employed to obtain an extensive collection of numeric pressure curves by changing engine geometry (e.g. compression ratios from 10 to 20 were adopted), operative conditions and wall heat transfer laws. The in-cylinder mass leakage has been taken into account in the model.Moreover, in order to assess the reliability and robustness of each method, the typical measurement errors and disturbances related to indicating analysis have been taken into account. The capability of the investigated methods to provide the correct TDC position in presence of the above mentioned errors has been evaluated.
2008
2008 SAE Brasil Congress and Exhibit
Sao Paulo; Brazil;
7-9 October 2008;
PIPITONE E, BECCARI A, BECCARI S (2008). Reliable TDC position determination: a comparison of different thermodynamic methods through experimental data and simulations. SAE TECHNICAL PAPER, 1-11 [10.4271/2008-36-0059].
File in questo prodotto:
File Dimensione Formato  
SAE_2008-36-0059.pdf

Solo gestori archvio

Tipologia: Versione Editoriale
Dimensione 413.27 kB
Formato Adobe PDF
413.27 kB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10447/34637
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 16
  • ???jsp.display-item.citation.isi??? ND
social impact