Özet:

Homegeneous charge compression ignition (HCCI) combustion can achieve very low NOx and soot emissions but knocking and misfiring restrict the operating range of this kind of engines. In this work, n-butanol which has low reactivity and high volatility blended with n-heptane that choosen as reference fuel in this study with various rates (25 vol% and 50 vol%). The experiments performed at various engine speeds (800-1800) and lambda (λ=1.6-2.95) at full load and 60 oC inlet air temperature. the parameters such as in-cylinder pressure, heat release rate, CA10, ringing intensity, thermal efficiency, brake torque, power output, specific fuel consumption, and HC and CO emissions were determined. The results showed that both in-cylinder pressure and heat release rate decreased with increasing lambda. Increasing amount of n-butanol in the charge mixture resulted a decrease both in-cylinder pressure and heat release rate. n-butanol also provided retarded combustion phasing and increased CA10. Ringing intensity decreased with increasing both lambda and n-butanol content in the mixture. Thermal efficiency increased with n-butanol. HC and CO emissions increased with increasing lambda. HC and CO emissions increased with increasing amount of n-butanol in the charge mixture. Operating range of HCCI engine was expanded with n-butanol in both knocking and misfiring zones.

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