Auto-ignition Modeling in a Spark Ignition Internal Combustion Engine Fueled with Gaseous Fuels with Variable Methane Number

A semi-empirical model for determining Knock Occurrence Crank Angle (KOCA) in a Cooperative Fuel Research (CFR) engine was developed. The model is based on the Integral Model approach and experimental data collected in a factorial 23 with axial and central runs experiment. Mixtures of CH4/H2 were employed as fuel. The model was accurate enough to predict KOCA with a maximum and minimum error of just 3.6 and 0.9 degrees respectively. To study the auto-ignition chemistry and its relationship with the knock resistance of gaseous fuels, the Methane Number of CO/CO2/H2 mixtures were measured. A correlation for estimating Methane Number as a function of fuel compositions was proposed. The proposed correlation is a good tool for estimating the Methane Number of fuels with high concentration of carbon dioxide, carbon monoxide and hydrogen. A comprehensive evaluation of the accuracy of a detailed chemical kinetics mechanism for predicting KOCA in a CFR engine was carried out. The spark ignition engine model of Chemkin Pro® software coupled with Gri-Mech. 3.0 chemical kinetics mechanism was used to model auto-ignition A set of equations for calculating residual gas fraction (x_r), inlet valve close gas temperature (T_IVC) and residual gas temperature?(T?_r) were proposed. Moreover, a technique for estimating combustion parameters from the indicator diagram was developed. Results reveal that accuracy of the mechanism used for estimating KOCA decreases as compression ratio decreases. This result is consistent with the lack of accuracy of the mechanism for predicting ignition delay time of gaseous fuel at low temperature.

• Autores: Amador Díaz, Germán Javier
• Fecha de publicación: 2017
• Institución: Universidad del Norte
• Repositorio: Repositorio Uninorte
• Idioma: eng
• OAI Identifier: oai:manglar.uninorte.edu.co:10584/7860
• Acceso en línea: http://hdl.handle.net/10584/7860
• Palabra clave: Motores de combustión interna -- Pruebas; Modelos (Ingeniería)
• License: http://purl.org/coar/access_right/c_abf2