Studi Eksperimen Pengaruh Modifikasi Intake Port Dan Exhaust Port Terhadap Unjuk Kerja Engine Empat Langkah Satu Silinder 115cc

Farhansyah, Bintang Ali Farhansyah (2026) Studi Eksperimen Pengaruh Modifikasi Intake Port Dan Exhaust Port Terhadap Unjuk Kerja Engine Empat Langkah Satu Silinder 115cc. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Keterbatasan proses pengecoran pada produksi kepala silinder sering kali menghasilkan permukaan saluran yang kasar dan berpori, sehingga dapat menyebabkan hambatan aliran udara dan menurunkan efisiensi mesin. Penelitian ini menganalisis pengaruh modifikasi diameter serta variasi tingkat kekasaran permukaan pada saluran intake dan exhaust terhadap unjuk kerja dan emisi gas buang mesin 115 cc satu silinder 4 langkah dengan menggunakan bahan bakar Pertalite. Eksperimen dilakukan dengan memperbesar diameter saluran intake dari 21 mm menjadi 23 mm dan saluran exhaust dari 19 mm menjadi 21 mm, serta menerapkan variasi tingkat kekasaran permukaan, yaitu kondisi standar dibandingkan dengan proses polishing menggunakan grit 600, 800, 1000, dan 1200. Tujuan penelitian ini adalah untuk mengetahui pengaruh variasi diameter dan tingkat kehalusan permukaan saluran terhadap performa mesin serta emisi gas buang.Hasil pengujian menunjukkan bahwa pada kondisi permukaan standar, performa puncak terjadi pada putaran 9000 RPM dengan daya sebesar 7,585 HP, torsi 6,006 N.m, BMEP 663,738 kPa, BSFC 0,000817 kg/W.h, dan efisiensi termal 9,027%. Sementara itu, variasi polishing grit 1200 menghasilkan performa puncak pada putaran yang sama dengan daya sebesar 10,406 HP, torsi 8,240 N.m, BMEP 910,604 kPa, BSFC 0,000550 kg/W.h, dan efisiensi termal 13,41%. Jika dibandingkan dengan kondisi standar, penggunaan polishing grit 1200 meningkatkan daya sebesar 37,19%, torsi sebesar 37,20%, BMEP sebesar 37,19%, serta efisiensi termal sebesar 48,55%. Selain itu, nilai BSFC mengalami penurunan sebesar 32,68%, yang menunjukkan bahwa konsumsi bahan bakar spesifik menjadi lebih efisien. hjnnnjjjjjPeningkatan performa pada putaran tinggi terjadi karena aliran massa fluida pada saluran intake dan exhaust menjadi lebih lancar akibat berkurangnya hambatan permukaan. Namun, pada kondisi idle, permukaan dinding saluran yang terlalu halus, khususnya pada grit 1200, dapat meningkatkan emisi HC akibat fenomena kondensasi bahan bakar pada dinding saluran. Secara keseluruhan, modifikasi porting dan polishing dengan bahan bakar Pertalite terbukti efektif meningkatkan performa mesin pada putaran tinggi, terutama pada variasi grit 1200. Meskipun demikian, kondisi permukaan standar masih lebih optimal dalam menekan emisi gas buang pada putaran rendah. ================================================================================================================================
The limitations of the casting process in cylinder head production often result in rough and porous port surfaces, which can create airflow resistance and reduce engine efficiency. This study analyzes the effect of diameter modification and variations in surface roughness levels in the intake and exhaust ports on the performance and exhaust gas emissions of a 115 cc single-cylinder four-stroke engine using Pertalite fuel. The experiment was conducted by increasing the intake port diameter from 21 mm to 23 mm and the exhaust port diameter from 19 mm to 21 mm, while applying different surface roughness variations, namely the standard condition and polishing using 600, 800, 1000, and 1200 grit levels. The objective of this study was to determine the effect of port diameter modification and surface smoothness variation on engine performance and exhaust gas emissions.The test results showed that under the standard surface condition, peak performance occurred at 9000 RPM, producing a power output of 7.585 HP, torque of 6.006 N.m, BMEP of 663.738 kPa, BSFC of 0.000817 kg/W.h, and thermal efficiency of 9.027%. Meanwhile, the 1200-grit polishing variation produced peak performance at the same engine speed, with a power output of 10.406 HP, torque of 8.240 N.m, BMEP of 910.604 kPa, BSFC of 0.000550 kg/W.h, and thermal efficiency of 13.41%. Compared with the standard condition, the 1200-grit polishing treatment increased power by 37.19%, torque by 37.20%, BMEP by 37.19%, and thermal efficiency by 48.55%. In addition, BSFC decreased by 32.68%, indicating improved specific fuel consumption efficiency.The improvement in performance at high engine speeds occurred because the mass flow of fluid through the intake and exhaust ports became smoother due to reduced surface resistance. However, under idle conditions, excessively smooth port surfaces, particularly the 1200-grit variation, may increase HC emissions due to fuel condensation on the port walls. Overall, porting and polishing modifications using Pertalite fuel were proven to be effective in improving engine performance at high engine speeds, especially with the 1200-grit polishing variation. Nevertheless, the standard surface condition remained more optimal in reducing exhaust gas emissions at low engine speeds.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Intake Port,Polishing, Unjuk Kerja Mesin, Kekasaran Permukaan, Emisi Gas Buang, Intake port ,Polishing, Engine Performance,Surface Roughness , Exhaust Emissions.
Subjects:	T Technology > TJ Mechanical engineering and machinery > TJ265.E23 Thermodynamics. T Technology > TJ Mechanical engineering and machinery > TJ324.5 Fuel systems T Technology > TJ Mechanical engineering and machinery > TJ785 Internal combustion engines. Spark ignition
Divisions:	Faculty of Vocational > Mechanical Industrial Engineering (D4)
Depositing User:	Bintang Ali Farhansyah
Date Deposited:	27 Jul 2026 02:11
Last Modified:	27 Jul 2026 02:11
URI:	http://repository.its.ac.id/id/eprint/137641

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