Examinando por Autor "Mejía, Luz A."

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  • Miniatura
    PublicaciónAcceso abierto
    Engine data collection and development of a pilot driving cycle for Pereira city by using low cost diagnostic tools
    (Universidad del Valle, 2017-07-01) Romero, Carlos A.; Mejía, Luz A.; Acosta, Ricardo
    (Eng) The objective of this paper is to present a methodology designed to develop a driving cycle to model traffic in the Pereira city in Colombia. Under the scope of this pilot work, four different gasoline passenger cars furnished with real time datalogging equipment were used to collect speed-time data under actual traffic along Pereira urban area. The speed-acceleration characteristics were analyzed, and target driving parameters were defined and evaluated. The designed method for building the driving cycle was then applied. As a result, a simple driving schedule for analyzing propulsion, fuel consumption rate, and emission control strategies of automobiles under Pereira downtown conditions has been proposed. Under the scope of the same project, was also studied the utility of the engine specific data collected during the vehicle operation for the purposes of engine performance assessment.
  • Miniatura
    PublicaciónAcceso abierto
    Identificación de parámetros dinámicos de la suspensión de un vehículo.
    (2015-05-11) Mejía, Luz A.; Valero, Francisco; Mata, Vicente
    En el presente trabajo se aborda la identificación de parámetros dinámicos en vehículos automóviles. Paso previo al desarrollo del problema de identificación, se desarrolla un modelo dinámico para la suspensión delantera de un vehículo de competición. El modelo dinámico se reduce mediante dos metodologías diferentes. La primera se basa en la Descomposición en Valores Singulares y la segunda por dos pasos consecutivos: eliminación de parámetros dinámicamente poco contributivos y Descomposición en Valores Singulares. Finalmente, ambos modelos son analizados y validados mediante el cruce de datos para otras trayectorias diferentes a las de identificación. El modelo obtenido utilizando la eliminación de parámetros poco contributivos reproduce de muy buena manera el comportamiento dinámico del sistema ante la inclusión de errores, por lo que dicha metodología se presenta como la más viable para la obtención del conjunto de parámetros base. Abstract This work presents the identification of dynamic parameters in automotive vehicles. In order to develop the identification problem, a dynamic model is obtained for the front suspension of a race car. Two new dynamic models are developed, the first of which is based on the Singular Value Decomposition (SVD), while the second comprises two consecutive steps: elimination of less contributive parameters and application of a SVD method. Finally, both models are analyzed and validated by means of data cross-referencing for new trajectories other than those used during the identification process. The model obtained using the elimination reproduces the dynamic behavior with very good approximation even with the inclusion of errors, so it is presented as the most viable methodology for obtaining base parameters.