Comparative evaluation of pongamia biodiesel with open and re-entrant combustion chambers in a DI diesel engine

Abstract

The influence of 20% blend of Pongamia Oil Methyl Ester (POME20) as alternative diesel fuel has been studied using a kirloskar made single cylinder, four stroke, direct injection diesel engine. Without altering the compression ratio of the engine, the piston’s combustion chamber geometry was modified to have Shallow depth combustion chamber, Toroidal combustion chamber, Shallow depth re-entrant type combustion chamber and Toroidal re-entrant type combustion chamber from the standard Hemispherical open type combustion chamber. Performance and emission tests were conducted for these five types of combustion chamber geometries to study the performance characteristics such as brake thermal efficiency, brake specific fuel consumption and emission characteristics such as unburned hydrocarbons, carbon monoxide, oxides of nitrogen and smoke emissions. The test results showed that substantially higher brake thermal efficiency and lower specific fuel consumption for toroidal re-entrant type combustion chamber. Sharp reduction of particulates, carbon monoxide and unburnt hydrocarbons were observed for toroidal re-entrant type combustion chamber compared to the other two. On the other hand oxides of nitrogen (NOx) were higher for toroidal re-entrant type combustion chamber. Ozet: Alternatif bir dizel yakit olarak Hint Kayin Agaci Yagi Metil Esteri’nin %20 oraninda karisiminin (POME20) etkisi, Kirloskar yapimi tek silindirli, dort zamanli, dogrudan puskurtmeli bir dizel motorda calisilmistir. Motorun sikistirma oranini degistirmeden, piston uzerindeki acik yarim kure seklindeki yanma odasi geometrisi sig bir yanma odasi, halka sekilli (toroidal) yanma odasi, sig derinlikli ve yeniden girisli yanma odasi ve halka sekilli yeniden girisli yanma odasi olacak sekilde degistirilmistir. Performans ve salinim testleri sayilan bu bes adet yanma odasi icin fren termal verimi, fren ozgul yakit tuketimi gibi performans karakteristikleri ve yanmamis hidrokarbonlar, karbon monoksit, nitrojen oksitleri ve duman salinimlari gibi salinim karakteristikleri acisindan calisilmistir. Test sonuclari halka seklinde yeniden girisli yanma odasi icin dikkate deger miktarda yuksek fren termal verimi ve dusuk ozgul yakit tuketimi gostermistir. Ayni yanma odasi icin partikul madde salinimi, karbon monoksit ve yanmamis hidrokarbon degerlerinde de diger iki yanma odasi ile karsilastirildiginda keskin dusus gozlemlenmistir. Diger taraftan bu yanma odasi tipi icin nitrojen oksitler (NOx) daha yuksektir.