Influence of the compression ratio on the performance and emission characteristics of a vcr diesel engine fuelled with alcohol blended fuels

Abstract

The  present  study  is  an  experimental  study  that  investigates  the  performance  and  emission  characteristics of a variable compression ratio (VCR) diesel engine when the engine is fuelled  with diesel, biodiesel, and small amount of alcohol blended fuels. The experimental study was  evaluated with a single cylinder, water cooled, multi fuel VCR diesel test engine. The experimental  results showed that increasing compression ratio improves performance characteristics such  as brake thermal efficiency and specific fuel consumption of the test engine for all test fuels.  However, increasing compression ratio caused to increase of NOx and CO2 emissions. Blending  alcohol with diesel fuel showed a slight decrement in the means of brake thermal efficiency  and thus elevated specific fuel consumption values. The maximum increment of specific fuel  consumption  was  measured  as  0,34%  for  diesel-alcohol  blends.  But,  blending  alcohols  with  biodiesel fuel improved performance characteristics of the engine compared to diesel fuel up to  2,65%. Blending biodiesel with alcohols showed improvement in the means of NOx emissions  up to 6,01%.