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A convective mass transfer model for predicting vapor formation within the cooling system of an internal combustion engine after shutdown / Rocco Piccione in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 2 (Fevrier 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 2 (Fevrier 2010) . - 10 p. Titre : A convective mass transfer model for predicting vapor formation within the cooling system of an internal combustion engine after shutdown Type de document : texte imprimé Auteurs : Rocco Piccione, Auteur ; Antonio Vulcano, Auteur ; Sergio Bova, Auteur Année de publication : 2010 Article en page(s) : 10 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Automotive  components  Cooling  Internal  combustion  engines  Mass  transfer  Pumps  Shafts  Thermodynamics Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : In the usual liquid cooling system of an internal combustion engine a centrifugal pump is driven by the crankshaft and imposes a coolant flow, which transfers heat from the engine walls to the radiator. Therefore, as the engine is switched-off, the coolant flow also stops, while metal temperature may be particularly high after a period of high load operation; coolant vaporization in the cylinder head passages may occur in these conditions, with a pressure increase inside the cooling circuit. A numerical dynamic model was developed to predict this phenomenon, often called after-boiling among engine manufacturers. The model structure includes thermodynamic equations to compute heat transfer as well as mass transfer equations to determine the vaporized mass of the coolant, which occurs in cylinder head passages and the vapor condensation within the radiator. The developed mathematical model was validated against test data carried out on a production four-stroke spark-ignition engine, and simulation results show good agreement with experimental data. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000002 [...] [article] A convective mass transfer model for predicting vapor formation within the cooling system of an internal combustion engine after shutdown [texte imprimé] / Rocco Piccione, Auteur ; Antonio Vulcano, Auteur ; Sergio Bova, Auteur . - 2010 . - 10 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 2 (Fevrier 2010) . - 10 p. Mots-clés : Automotive  components  Cooling  Internal  combustion  engines  Mass  transfer  Pumps  Shafts  Thermodynamics Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : In the usual liquid cooling system of an internal combustion engine a centrifugal pump is driven by the crankshaft and imposes a coolant flow, which transfers heat from the engine walls to the radiator. Therefore, as the engine is switched-off, the coolant flow also stops, while metal temperature may be particularly high after a period of high load operation; coolant vaporization in the cylinder head passages may occur in these conditions, with a pressure increase inside the cooling circuit. A numerical dynamic model was developed to predict this phenomenon, often called after-boiling among engine manufacturers. The model structure includes thermodynamic equations to compute heat transfer as well as mass transfer equations to determine the vaporized mass of the coolant, which occurs in cylinder head passages and the vapor condensation within the radiator. The developed mathematical model was validated against test data carried out on a production four-stroke spark-ignition engine, and simulation results show good agreement with experimental data. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000002 [...]

Engine rapid shutdown / Rocco Piccione in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 7 (Juillet 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 7 (Juillet 2010) . - 10 p. Titre : Engine rapid shutdown : experimental investigation on the cooling system transient response Type de document : texte imprimé Auteurs : Rocco Piccione, Auteur ; Sergio Bova, Auteur Année de publication : 2011 Article en page(s) : 10 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Automotive  components  Cooling  Engine  cylinders  Ignition  Internal  combustion  engines  Sparks  Transient  response  Valves Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Experimental measurements have been taken on a production four-cylinder, multipoint (fuel) injection spark-ignition engine, 1.2 dm3 displacement with a four-valve per cylinder aluminum head, and a 60 kW at 5500 rpm rated power. The aim of the investigation was to understand the behavior of the cooling system of a small automotive engine, which was operated for a prolonged period at high speed under full or part load, then brought to idle for a short period and finally shut down. In this study, the effects of different loads, idle operation time, and lengths of the engine-radiator piping were analyzed. In particular, experimental tests were carried out with the engine running at 4000 rpm under different brake mean effective pressure values in the range 496 to 1133 kPa. In all experimental tests the engine was brought to idle in 5 s, and measurements were repeated for different values of the idle operation time ranging from 1 s to 80 s. Test data of coolant conditions and metal temperature at 26 points of the engine head and liner were recorded. The cooling circuit was instrumented with transparent tubes at the radiator inlet and photographs of the vapor phase moving to the radiator were taken during experimental tests. The volume of leaked coolant as a function of time was also measured. Additional tests were carried out to evaluate the effects of different lengths of the engine-radiator piping on the after-boiling phenomenon. Finally, in order to make the results applicable also to nonautomotive engines, measurements were repeated without the standard cabin heater and the associated piping. The investigation results show that as the engine is shut down and coolant flow stops, the head metal may be hot enough to vaporize a fraction of the coolant contained in the cylinder head passages, causing the pressure within the cooling circuit to rise above the threshold value of the radiator cap pressure valve and, consequently, an important quantity of the coolant to be expelled. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000007 [...] [article] Engine rapid shutdown : experimental investigation on the cooling system transient response [texte imprimé] / Rocco Piccione, Auteur ; Sergio Bova, Auteur . - 2011 . - 10 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 7 (Juillet 2010) . - 10 p. Mots-clés : Automotive  components  Cooling  Engine  cylinders  Ignition  Internal  combustion  engines  Sparks  Transient  response  Valves Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Experimental measurements have been taken on a production four-cylinder, multipoint (fuel) injection spark-ignition engine, 1.2 dm3 displacement with a four-valve per cylinder aluminum head, and a 60 kW at 5500 rpm rated power. The aim of the investigation was to understand the behavior of the cooling system of a small automotive engine, which was operated for a prolonged period at high speed under full or part load, then brought to idle for a short period and finally shut down. In this study, the effects of different loads, idle operation time, and lengths of the engine-radiator piping were analyzed. In particular, experimental tests were carried out with the engine running at 4000 rpm under different brake mean effective pressure values in the range 496 to 1133 kPa. In all experimental tests the engine was brought to idle in 5 s, and measurements were repeated for different values of the idle operation time ranging from 1 s to 80 s. Test data of coolant conditions and metal temperature at 26 points of the engine head and liner were recorded. The cooling circuit was instrumented with transparent tubes at the radiator inlet and photographs of the vapor phase moving to the radiator were taken during experimental tests. The volume of leaked coolant as a function of time was also measured. Additional tests were carried out to evaluate the effects of different lengths of the engine-radiator piping on the after-boiling phenomenon. Finally, in order to make the results applicable also to nonautomotive engines, measurements were repeated without the standard cabin heater and the associated piping. The investigation results show that as the engine is shut down and coolant flow stops, the head metal may be hot enough to vaporize a fraction of the coolant contained in the cylinder head passages, causing the pressure within the cooling circuit to rise above the threshold value of the radiator cap pressure valve and, consequently, an important quantity of the coolant to be expelled. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000007 [...]