To investigate the effect of EGR temperature on engine
performance and emissions [29–33] three different engine
speeds namely 1130, 1420 and 1710 rpm are considered at
100% load, covering the entire engine operating speed
range. It must be stated at this point that it was preferred to
provide results for the full load case (due to space
limitations) due to its importance considering fuel consumption
as well as pollutant emissions. However, results
at lower engine load conditions were also investigated. For
each test case various EGR rates are examined namely 5%,
10% and 15% while injection advance (91 ATDC) and
boost pressure are kept constant. For each test case,
various EGR temperatures are examined ranging from
90 1C up to 240 1C using steps of 50 1C. The previous
temperature range is a representative range of temperatures
when using cooled EGR at full load since in many cases the
cooling media is the engine coolant. The EGR percentage
is defined as