International Journal of Rotating Machinery
Volume 2008 (2008), Article ID 175956, 13 pages
doi:10.1155/2008/175956
Abstract
Up to now, diesel engines with direct fuel injection are the
propulsion systems with the highest efficiency for mobile
applications. Future targets in reducing CO2 -emissions with regard
to global warming effects can be met with the help of these
engines. A major disadvantage of diesel engines is the high soot
and nitrogen oxide emissions which cannot be reduced completely
with only engine measures today. The present paper describes two
different possibilities for the simultaneous in-cylinder reduction
of soot and nitrogen oxide emissions. One possibility is the
optimization of the injection process with a new injection
strategy the other one is the use of water diesel emulsions with
the conventional injection system. The new injection strategy for
this experimental part of the study overcomes the problem of
increased soot emissions with pilot injection by separating the
injections spatially and therefore on the one hand reduces the
soot formation during the early stages of the combustion and on
the other hand increases the soot oxidation later during the
combustion. Another method to reduce the emissions is the
introduction of water into the combustion chamber. Emulsions of
water and fuel offer the potential to simultaneously reduce NOx
and soot emissions while maintaining a high-thermal efficiency.
This article presents a theoretical investigation of the use of
fuel-water emulsions in DI-Diesel engines. The numerical
simulations are carried out with the 3D-CFD code KIVA3V. The use
of different water diesel emulsions is investigated and assessed with the numerical model.