Transient EGR in a High-Speed DI Diesel Engine for a set of different EGR-routings

• EGR has been proven to reduce NOx emissions from diesel engines significantly and is nowadays widely used in production engines. To reach future emission legislation standards, alternative EGR-routings that deliver higher EGR- rates get into the focus of researchers. As the steady-state emissions are reduced more and more, the emission peaks in transient parts of driving cycles gain importance. Therefore it is interesting to analyze the transient behavior of different EGR-routings. In this work, a 1-D simulation is performed in GT-Power for a 1.9 liter passenger car diesel engine equipped with cooled short-route EGR and a variable geometry turbine. For calibration of the simulation, load transients are measured including the measurement of transient EGR-rates using a fast CO2-analyzer and cylinder pressure to obtain heat-release data. A database with heat-release rates for transient combustion is collected to enable the simulation to run with real combustion data at all points of the transients. The transient EGR-rate as well as the intake pressure are used as criteria to chose the right heat-release rate for a certain cycle. A set of different ways of supplying EGR, namely hybrid EGR, pump-assisted EGR and a reed valve in the EGR- circuit are then implemented in the simulation software and analyzed with respect to transient response and fuel consumption. Another aspect of the analysis is the possibility to control the EGR-rate during the transient. This includes positive load transients with EGR-shutoff as well as negative load transients with need for fast EGR-delivery.

Subject headings

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik -- Farkostteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering -- Vehicle Engineering (hsv//eng)

Keyword

EGR

transient EGR

Publication and Content Type

ref (subject category)

art (subject category)