P. Bashi Shahabi, H. Niazmand, M.r Modarres Razavi,
Volume 1, Issue 1 (1-2011)
Abstract
Increase of environmental pollution and restricted emission legislations have forced companies to produce automobiles with lower air pollutants. In this respect, discharge of blowby gases into the environment has been prohibited and their recirculation into the combustion chamber is proposed as an alternative solution. In addition, using EGR technique to control and reduce nitrogen oxides in internal combustion engines has been quite effective. An important common feature of these two methods is the fact that improper EGR/blowby distribution leads to the increase in other pollutants and the significant engine power reduction. Therefore, the study of important factors in maldistribution of the injected gases is of great practical importance. Besides the injection position that has significant role on distribution of injected gases, it seems that other parameters such as engine speed, injection velocity and angle may affect the distribution of injected gases. In this numerical study, a new technique is used to determine the effect of these parameters on distribution of injected EGR or blowby gases into the EF7 intake manifold. Numerical calculations are performed for three injection velocities, five injection angles and three different engine speeds. It was found that recirculated gases distribution is slightly influenced by the injection angle and injection velocity, while the engine speed is the most influential factor.
S. K. Kamboj, M. N. Karimi,
Volume 3, Issue 2 (6-2013)
Abstract
Alcohols have been used as a fuel for engines since 19th century. Among the various alcohols, ethanol and
methanol are known as the most suited renewable, bio-based and ecofriendly fuel for spark-ignition (SI)
engines. The most attractive properties of ethanol and methanol as an SI engine fuel are that it can be
produced from renewable energy sources such as sugar, cane, cassava, many types of waste biomass
materials, corn and barley. In addition, ethanol has higher evaporation heat, octane number and
flammability temperature therefore it has positive influence on engine performance and reduces exhaust
emissions. In this study, the effects of unleaded iso-octane, unleaded iso-octane–ethanol blend (E10) and
isooctane-methanol blend (M10) on engine performance were investigated experimentally in a single
cylinder four-stroke spark-ignition engine. The tests were performed by varying the throttle position,
engine speed and loads. Three sets of observations were recorded at (1301 rpm, 16.8 Kg load), (1468 rpm,
15.8 Kg load) and (1544 rpm, 10 Kg load) for all tested fuels. The results of the engine test showed that IP,
IMEP, Volumetric efficiency and thermal efficiency was higher for the E10 fuel and BSFC was lower. In
general, most suited blend for SI engines has been specified as a blend of 10% ethanol. It was also observed
that better performance was recorded during second set of observation for all the tested fuels. It was also
found that ethanol–gasoline blends allow increasing compression ratio (CR) without knock occurrence.
