Heat Release Analysis of Engine Pressure Data
TL;DR: In this article, a heat release model using a one zone description of the cylinder contents with thermodynamic properties represented by a linear approximation is presented. But the model does not consider the effects of heat transfer, crevice flows and fuel injection.
Abstract: In analyzing the processes inside the cylinder of an internal combustion engine, the principal diagnostic at the experimenter's disposal is a measured time history of the cylinder pressure. This paper develops, tests, and applies a heat release analysis procedure that maintains simplicity while including the effects of heat transfer, crevice flows and fuel injection. The heat release model uses a one zone description of the cylinder contents with thermodynamic properties represented by a linear approximation. Applications of the analysis to a single-cylinder spark-ignition engine, a special square cross-section visualization spark-ignition engine, and a direct-injection stratified charge engine are presented.
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TL;DR: In this article, an experimental study has been carried out to provide qualitative and quantitative insight into gas to wall heat transfer in a gasoline fueled homogeneous charge compression Ignition (HCCI) engine.
Abstract: An experimental study has been carried out to provide qualitative and quantitative insight into gas to wall heat transfer in a gasoline fueled Homogeneous Charge Compression Ignition (HCCI) engine. Fast response thermocouples are embedded in the piston top and cylinder head surface to measure instantaneous wall temperature and heat flux. Heat flux measurements obtained at multiple locations show small spatial variations, thus confirming relative uniformity of incylinder conditions in a HCCI engine operating with premixed charge. Consequently, the spatially-averaged heat flux represents well the global heat transfer from the gas to the combustion chamber walls in the premixed HCCI engine, as confirmed through the gross heat release analysis. Heat flux measurements were used for assessing several existing heat transfer correlations. One of the most popular models, the Woschni expression, was shown to be inadequate for the HCCI engine. The problem is traced back to the flame propagation term which is not appropriate for the HCCI combustion. Subsequently, a modified model is proposed which significantly improves the prediction of heat transfer in a gasoline HCCI engine and shows very good agreement over a range of conditions.
439 citations
223 citations
01 Mar 2000
TL;DR: In this paper, an experimental investigation was conducted to determine the emissions characteristics of higher alcohols and gasoline (UTG96) blends, while lower alcohols (methanol and ethanol) have been...
Abstract: An experimental investigation was conducted to determine the emissions characteristics of higher alcohols and gasoline (UTG96) blends. While lower alcohols (methanol and ethanol) have been ...
201 citations
TL;DR: In this paper, it is shown that the fraction of the fuel's chemical energy which has been released and the amount of fuel-air mixture burned, within the engine's cylinder, can be accurately estimated from a one-zone analysis if appropriate values for the "average ratio of specific heats" of the contents are used.
Abstract: A First Law analysis based on the cylinder pressure variation during combustion is a commonly used diagnostic for determining actual spark-ignition engine burning rates. Both simple one-zone and more complex two-zone models have been developed for this purpose. It is shown that the fraction of the fuel's chemical energy which has been released and the fraction of fuel-air mixture burned, within the engine's cylinder, can be accurately estimated from a one-zone analysis if appropriate values for the “average ratio of specific heats”, y¯, of the one-zone contents are used. These values are determined by matching the output of the one-zone analysis to that of the more rigorous two-zone analysis of the same cylinder pressure data. Use of this one-zone burning rate analysis procedure is illustrated.
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416 citations
01 Feb 1974
TL;DR: In this paper, a model for describing turbulent flame propagation in internal combustion engines is presented, and an approximate analytic method for determining the equilibrium state of the burned gases is also presented.
Abstract: A model for describing turbulent flame propagation in internal combustion engines is presented. An approximate analytic method for determining the equilibrium state of the burned gases is also presented. To verify the predictions of the model, experiments were carried out in a single-cylinder research engine at speeds from 1000-3200 rpm, spark advances from 30-110 deg btc and fuel-air equivalence ratios from 0.7-1.5. Simultaneous measurements of the cylinder pressure and the position of the flame front as a function of crank angle were made, and good agreement with the predictions of the model was obtained for all operating conditions.
407 citations
01 Feb 1975
TL;DR: This paper provides a user oriented description of techniques for the measurement and analysis of engine cylinder pressures developed for piexoelectric transducers and for digital systems of data acquisition and analysis.
Abstract: This paper provides a user oriented description of techniques for the measurement and analysis of engine cylinder pressures. These techniques were developed for piexoelectric transducers and for digital systems of data acquisition and analysis. Test cell procedures are described for transducer preparation and calibration, and for association of each pressure with its appropriate crank angle. Techniques are also described for evaluating the accuracy of pressure data and for eliminating specific errors. Two examples of uses for pressure data are discussed: the calculation of heat release rate in conventional engines, and the computation of internal flows in divided chamber engines. /GMRL/
274 citations