Ön karışımlı benzin dolgusunun HCCI-DI motorunda yanma ve egzoz emisyonlarına etkilerinin incelenmesi

Bu çalışmada, ön karışımlı benzin yakıtının yanma ve egzoz emisyonları üzerine etkileri tek silindirli bir HCCIDI motorunda incelenmiştir. Deneyler motorun maksimum moment devri olan 2200 d/d ve tam yük çalışma şartlarında yapılmıştır. Ön karışımlı benzin yakıt miktarı programlanabilir bir elektronik kontrol ünitesi ile kontrol edilmiş ve düşük basınçlı yakıt enjeksiyon sistemi ile motorun emme havasına püskürtülmüştür. Ön karışımlı benzin yakıtının oranı % 10, % 20 ve % 30 olacak şekilde değiştirilmiş, sonuçlar dizel yakıtı ile karşılaştırılmıştır. Deneysel çalışmalar sonucunda, iki aşamalı yanma (ön karışımlı HCCI yanması ve difuzyon yanması) gözlemlenmiştir. İlk aşama yanma kısmında, silindir içi basınç ve ısı dağılımında artış görülmüştür. İkinci aşama yanma kısmında ise, ön karışımlı benzin yakıtı ile daha düşük difüzyon yanması gerçeklemiştir. Çevrimden çevrime farklılıklar dizel yakıtı ve % 10 ön karışımlı benzin yakıtında oldukça azalmıştır. % 30 ön karışımlı benzin yakıtında duyulabilir miktarda vuruntu gerçeklemiştir. NOx -is zıt eğilim karakteristiği değişmiş ve her iki emisyonda iyileşmeler eş zamanlı olarak sağlanmıştır. Egzoz gaz sıcaklığı % 22 oranında azalırken, NOx ve is emisyonlarında % 16 ve % 65 oranında azalma sağlanmıştır. Diğer yandan HC ve CO emisyonlarında artış görülmüştür.

The investigation of the effects of premixed gasoline charge on HCCI-DI engine combustion and exhaust emissions

In this study, the effects of premixed ratio of gasoline on the combustion and exhaust emissions were investigated in a single-cylinder, HCCI-DI engine. The experiments were performed at the engine speed of 2200 rpm and maximum brake torque operating conditions. The amount of the premixed gasoline was controlled by a programmable electronic control unit (ECU) and the gasoline injection was conducted into the intake air charge using low pressure fuel injection system. The premixed ratio of gasoline was changed 10 %, 20 % and 30 % and results were compared to neat diesel operation. The experimental results show that two stage combustion (premixed HCCI combustion and diffusion combustion) was found. Increasing in-cylinder pressure and heat release was observed in the first stage of combustion. In the second stage of combustion, lower diffusion combustion was occurred with premixed gasoline fuels. Cycle-to-cycle variations were very small with the diesel fuel and 10 % gasoline premixed fuel. Audible knocking occurred with 30 % gasoline premixed fuel ratio. NOxsoot trade-off characteristics were changed and improvements were found simultaneously. NOx and soot emissions were decreased up to 16 % and 65 % respectively, while exhaust gas temperature decreased by 22 %. On the other hand, CO and HC emissions increased.

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