... The rate established by Li et al. [6] was replaced by the rate from Joshi and Wang [21] which... more ... The rate established by Li et al. [6] was replaced by the rate from Joshi and Wang [21] which is lower in order to decrease the predicted flame speed. ... J. Hydrogen Energy (2008), 33, (7), 1957-1964. [5] M. ´O Conaire; HJ Curran; JM Simmie; WJ Pitz; CK Westbrook, Int. J. Chem. ...
2014 IEEE Vehicle Power and Propulsion Conference (VPPC), 2014
ABSTRACT Action-reaction principle of Energetic Macroscopic Representation (EMR) and its Inversio... more ABSTRACT Action-reaction principle of Energetic Macroscopic Representation (EMR) and its Inversion Based Control (IBC) is used to organize subsystems interconnection of Noao, a plug-in series hybrid race car equipped with lithium-ion battery pack and an engine/generator set as its range extender, according to the physical causality. Results from drive test of the real car are used to validate the model. The objective of this paper is to provide a dynamic model of this car in order to improve its control scheme and analyse the impact of its optimisation.
2012 IEEE Transportation Electrification Conference and Expo (ITEC), 2012
ABSTRACT This article presents two simple methods to evaluate the fuel consumption of internal co... more ABSTRACT This article presents two simple methods to evaluate the fuel consumption of internal combustion engines. Furthermore, it points out the link between piston volume, engine size and fuel consumption as it gives the possibility to visualize the chosen working points inside an internal combustion engine operation points map. This leads to the fact that this approach is a very helpful tool for the design of hybrid systems including internal combustion engines. The two presented methods, one very simple, one more elaborated, are interesting as first approach of internal combustion engine sizing and to evaluate the consumption of internal combustion engine. The results for six pure internal combustion engines on two different driving cycles have been compared to literature data showing extremely satisfying accuracy. An application on a series hybrid vehicle underlines the potential of fuel savings due to hybrid architecture.
The aim of this study is to quantify the impact of intake port geometry on in-cylinder flow. The ... more The aim of this study is to quantify the impact of intake port geometry on in-cylinder flow. The in-cylinder aerodynamics of an optical engine has been characterized using particle image velocimetry (PIV). Many geometries have been tested and their impact has been evaluated by an estimation of the tumble ratio, an analysis of the cycle-to-cycle variations and a flow structure analysis based on proper orthogonal decomposition (POD). Such a tool allows the reduction of the PIV database in order to consider in-cylinder aerodynamic control by a device placed in the intake port. This simplification is based on a reduction of the number of modes and a polynomial fitting of the POD coefficients. Thus, some new geometries have been numerically created, and their impact on the tumble ratio has been evaluated.
The role of different combustion modes during the development of ignition inside a rapid compress... more The role of different combustion modes during the development of ignition inside a rapid compression machine is discussed. The careful design of the UPMC-RCM is described, following the acknowledged recommendations concerning the reduction of the compression generated turbulence. A methodology is then proposed to investigate the influence of the residual post-compression turbulence level on the visible ignition kernel growth. Through the fuel nature, the single initial parameter varied is the ratio of the ignition delay to the post-compression turbulence decay characteristic time. For each fuel/air mixture, a high-speed camera captures the visible kernel growth.
The oxidation of syngas mixtures was investigated experimentally and simulated with an updated ch... more The oxidation of syngas mixtures was investigated experimentally and simulated with an updated chemical kinetic model. Ignition delay times for H 2 /CO/O 2 /N 2 /Ar mixtures have been measured using two rapid compression machines and shock tubes at pressures from 1 to 70 bar, over a temperature range of 914-2220 K and at equivalence ratios from 0.1 to 4.0. Results show a strong dependence of ignition times on temperature and pressure at the end of the compression; ignition delays decrease with increasing temperature, pressure, and equivalence ratio. The reactivity of the syngas mixtures was found to be governed by hydrogen chemistry for CO concentrations lower than 50% in the fuel mixture. For higher CO concentrations, an inhibiting effect of CO was observed. Flame speeds were measured in helium for syngas mixtures with a high CO content and at elevated pressures of 5 and 10 atm using the spherically expanding flame method. A detailed chemical kinetic mechanism for hydrogen and H 2 /CO (syngas) mixtures has been updated, rate constants have been adjusted to reflect new experimental information obtained at high pressures and new rate constant values recently published in the literature. Experimental results for ignition delay times and flame speeds have been compared with predictions using our newly revised chemical kinetic mechanism, and good agreement was observed. In the mechanism validation, particular emphasis is placed on predicting experimental data at high pressures (up to 70 bar) and intermediate-to high-temperature conditions, particularly important for applications in internal combustion engines and gas turbines. The reaction sequence H 2 þ H _ O 2 $ _ H þ H 2 O 2 followed by H 2 O 2 ðþMÞ $ _ OH þ _ OH ðþMÞ was found to play a key role in hydrogen ignition under high-pressure and intermediate-temperature conditions. The rate constant for H 2 þ H _ O 2 showed strong sensitivity to high-pressure ignition times and has considerable uncertainty, based on literature values. A rate constant for this reaction is recommended based on available literature values and on our mechanism validation.
... The rate established by Li et al. [6] was replaced by the rate from Joshi and Wang [21] which... more ... The rate established by Li et al. [6] was replaced by the rate from Joshi and Wang [21] which is lower in order to decrease the predicted flame speed. ... J. Hydrogen Energy (2008), 33, (7), 1957-1964. [5] M. ´O Conaire; HJ Curran; JM Simmie; WJ Pitz; CK Westbrook, Int. J. Chem. ...
2014 IEEE Vehicle Power and Propulsion Conference (VPPC), 2014
ABSTRACT Action-reaction principle of Energetic Macroscopic Representation (EMR) and its Inversio... more ABSTRACT Action-reaction principle of Energetic Macroscopic Representation (EMR) and its Inversion Based Control (IBC) is used to organize subsystems interconnection of Noao, a plug-in series hybrid race car equipped with lithium-ion battery pack and an engine/generator set as its range extender, according to the physical causality. Results from drive test of the real car are used to validate the model. The objective of this paper is to provide a dynamic model of this car in order to improve its control scheme and analyse the impact of its optimisation.
2012 IEEE Transportation Electrification Conference and Expo (ITEC), 2012
ABSTRACT This article presents two simple methods to evaluate the fuel consumption of internal co... more ABSTRACT This article presents two simple methods to evaluate the fuel consumption of internal combustion engines. Furthermore, it points out the link between piston volume, engine size and fuel consumption as it gives the possibility to visualize the chosen working points inside an internal combustion engine operation points map. This leads to the fact that this approach is a very helpful tool for the design of hybrid systems including internal combustion engines. The two presented methods, one very simple, one more elaborated, are interesting as first approach of internal combustion engine sizing and to evaluate the consumption of internal combustion engine. The results for six pure internal combustion engines on two different driving cycles have been compared to literature data showing extremely satisfying accuracy. An application on a series hybrid vehicle underlines the potential of fuel savings due to hybrid architecture.
The aim of this study is to quantify the impact of intake port geometry on in-cylinder flow. The ... more The aim of this study is to quantify the impact of intake port geometry on in-cylinder flow. The in-cylinder aerodynamics of an optical engine has been characterized using particle image velocimetry (PIV). Many geometries have been tested and their impact has been evaluated by an estimation of the tumble ratio, an analysis of the cycle-to-cycle variations and a flow structure analysis based on proper orthogonal decomposition (POD). Such a tool allows the reduction of the PIV database in order to consider in-cylinder aerodynamic control by a device placed in the intake port. This simplification is based on a reduction of the number of modes and a polynomial fitting of the POD coefficients. Thus, some new geometries have been numerically created, and their impact on the tumble ratio has been evaluated.
The role of different combustion modes during the development of ignition inside a rapid compress... more The role of different combustion modes during the development of ignition inside a rapid compression machine is discussed. The careful design of the UPMC-RCM is described, following the acknowledged recommendations concerning the reduction of the compression generated turbulence. A methodology is then proposed to investigate the influence of the residual post-compression turbulence level on the visible ignition kernel growth. Through the fuel nature, the single initial parameter varied is the ratio of the ignition delay to the post-compression turbulence decay characteristic time. For each fuel/air mixture, a high-speed camera captures the visible kernel growth.
The oxidation of syngas mixtures was investigated experimentally and simulated with an updated ch... more The oxidation of syngas mixtures was investigated experimentally and simulated with an updated chemical kinetic model. Ignition delay times for H 2 /CO/O 2 /N 2 /Ar mixtures have been measured using two rapid compression machines and shock tubes at pressures from 1 to 70 bar, over a temperature range of 914-2220 K and at equivalence ratios from 0.1 to 4.0. Results show a strong dependence of ignition times on temperature and pressure at the end of the compression; ignition delays decrease with increasing temperature, pressure, and equivalence ratio. The reactivity of the syngas mixtures was found to be governed by hydrogen chemistry for CO concentrations lower than 50% in the fuel mixture. For higher CO concentrations, an inhibiting effect of CO was observed. Flame speeds were measured in helium for syngas mixtures with a high CO content and at elevated pressures of 5 and 10 atm using the spherically expanding flame method. A detailed chemical kinetic mechanism for hydrogen and H 2 /CO (syngas) mixtures has been updated, rate constants have been adjusted to reflect new experimental information obtained at high pressures and new rate constant values recently published in the literature. Experimental results for ignition delay times and flame speeds have been compared with predictions using our newly revised chemical kinetic mechanism, and good agreement was observed. In the mechanism validation, particular emphasis is placed on predicting experimental data at high pressures (up to 70 bar) and intermediate-to high-temperature conditions, particularly important for applications in internal combustion engines and gas turbines. The reaction sequence H 2 þ H _ O 2 $ _ H þ H 2 O 2 followed by H 2 O 2 ðþMÞ $ _ OH þ _ OH ðþMÞ was found to play a key role in hydrogen ignition under high-pressure and intermediate-temperature conditions. The rate constant for H 2 þ H _ O 2 showed strong sensitivity to high-pressure ignition times and has considerable uncertainty, based on literature values. A rate constant for this reaction is recommended based on available literature values and on our mechanism validation.
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Papers by Alan Keromnes