TY - JOUR
TI - Experimental investigations of effects of cooling/non cooling of EGR on two level of compression ratio in a common rail diesel engine
AU - Gajarlawar Nilesh
AU - Rao Gaddale Amba Prasad
AU - Murthy K Madhu
JN - Thermal Science
PY - 2015
VL - 19
IS - 6
SP - 1995
EP - 2002
PT - Article
AB - EGR cooling is followed for many years and proven as an efficient technique  for reducing NOx-PM emissions. EGR cooling helps in emission reduction of NOx  and PM. But, it brings associated issues like cooler fouling; misfiring in  cold condition, if cooling is not bypassed, during cold start. Also, it  increases HC and CO emissions thus leading to increased loading of diesel  oxidation catalyst. In the present study, two engine operating points were  chosen from EUDC part of modified NEDC cycle for India. The two set of  compression ratios were prepared. The NOx-PM along with HC and CO emissions  were measured with 18.5CR. The emissions with cooled EGR were taken first  which form the base optimization. The cooler was removed from the EGR circuit  and same measurements were done. In the third step, the increased NOx due to  non-cooled EGR was brought to the original value by increasing the Injection  rail pressure and EGR rates simultaneously. In this process, the PM emission  was found to be increasing marginally from its optimized value. The same  experimentation was repeated for the 16.5 compression ratio. Both the  compression ratios exhibit the similar trends of emissions. The magnitude of  NOx PM, HC and CO differs for both the compression ratios. In order to meet  the baseline optimized NOx-PM emissions with prime objective to get rid of  EGR cooler and gain cost saving, reduced compression ratio found to be  promising solution. There was marginal increase in CO and HC emission with  this approach.