International

This paper describes results obtained from CI engine performance running on dual fuel mode at fixed engine speed and four loads, varying the mixing system and pilot fuel quality, associated with fuel composition and cetane number. The experiments were carried out on a power generation diesel engine at 1500 m above sea level, with simulated biogas (60% CH4–40% CO2) as primary fuel, and diesel and palm oil biodiesel as pilot fuels.

Hydrogen addition to methane will have an important role to reach a fully developed hydrogen economy. The effects of this addition on the flame structure and CO emissions were evaluated in two different atmospheric burners. Four fuels with the following composition were used: 100%CH4, 2%H2+98%CH4, 6%H2+94%CH4 and 15%H2+85%CH4. In a single-port atmospheric burner, a decreasing trend in the height of the blue cone with hydrogen addition was determined. The increase in the laminar burning velocity was identified as the main effect on the behavior of this parameter.

Se preparó material activo partiendo de óxido de magnesio (MgO) grado industrial y grado reactivo adicionado con óxido de calcio (CaO).  En un lecho fijo empacado con partículas de material activo, se investigó el efecto que tienen la cantidad de CaO adicionado, la temperatura de calcinación, la velocidad espacial, el exceso de oxígeno y la composición de mezcla reactiva sobre la actividad, medida como conversión porcentual de metano.

For economic and environmental reasons natural gas begins to take an important participation as an energy source in the residential sector of Latin American cities placed at high altitudes: La Paz (3719 m), Santa Fe de Bogotá (2600 m), Mexico City (2240 m), Manizales (2150 m), Medellín (1550 m), Cali (1000 m) and others.

This paper presents the comparison of experimental results and computational fluid dynamics (CFD) simulations for a 600 MWe industrial pulverised coal power station. The power station measurements were made in a normal combustion mode and in an overfire air (OFA) mode. The agreement between the model and the data collected in the chimney is good; the NOx reduction modelled is in agreement with the measured one, but data taken in the flame show that the flame structure is imperfectly represented.

En este trabajo se estudia el efecto de la altitud sobre la potencia en motores de aspiración natural y turbosobrealimentados sin sistemas correctores, en función de la presión ambiental. La altitud sobre el nivel del mar tiene un notable efecto sobre la densidad del aire y su composición. Dado que los motores de combustión interna tienen sistemas de admisión y de inyección de combustible volumétricos, la altitud modifica el ciclo termodinámico de operación, y en consecuencia las prestaciones, así como las condiciones locales de combustión, y por tanto la formación de contaminantes.

En este trabajo se analiza el efecto de la altitud sobre los parámetros característicos de la combustión y sobre la formación de óxidos de nitrógeno (NOx) en motores diesel. Se estudiaron motores de aspiración natural y motores turboalimentados con diferentes grados de turboalimentación. Al incrementar la altitud se modifica la composición del aire atmosférico y disminuye su densidad debido a la disminución de la presión barométrica. Esto afecta la relación másica estequiométrica entre aire y combustible, por lo que el proceso de mezclado se modifica.

The effect of considering the gaseous fuel as ideal gas during the diagnostic procedure from experimental cylinder pressure signal from a Diesel engine is analysed. After the chemical characterization of the fuel and the estimation of the thermodynamic properties, the compressibility factor of the fuel was quantified under engine operating conditions, the prediction capability of four cubic state equations was tested, and finally their application was extended to the whole gaseous mixture throughout the engine cycle.

The use of the polytropic coefficient calculation during the compression process in the thermodynamic cycle of a reciprocating internal combustion engine is an interesting tool to minimize errors in the synchronization of pressure and volume signals, and to determine heat flux transferred to the cylinder walls. The accuracy of this calculation depends on the instantaneous values for pressure, volume, trapped mass and its composition, as well as on their variations.

In this work, the effect of water–oil emulsions on the engine performance and on the main pollutant emissions, NOx, total hydrocarbons (THC), soot, particulate matter (PM) and its composition, was studied. A turbocharger intercooler indirect injection (IDI) Diesel engine was tested under five different steady state operating conditions, selected from the transient cycle for light duty vehicles established in the European Emission Directive 70/220. Tests were performed using a commercial fuel as a reference and an emulsified fuel for each operating condition.