Analisis Perbandingan Unjuk Kerja Mesin 4 Langkah 1 Silinder Dengan Variasi Kekakuan Pegas Katup Berbahan Bakar Ethanol E-100

Sitorus, Ayub Einstein (2025) Analisis Perbandingan Unjuk Kerja Mesin 4 Langkah 1 Silinder Dengan Variasi Kekakuan Pegas Katup Berbahan Bakar Ethanol E-100. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Penelitian ini bertujuan untuk menganalisis pengaruh variasi kekakuan pegas katup terhadap unjuk kerja dan emisi gas buang Mesin Pembakaran Dalam 4 langkah 1 silinder berbahan bakar etanol E-100. Latar belakang penelitian ini didasari oleh kebutuhan akan energi alternatif yang ramah lingkungan sebagai bahan bakar mesin mengantikan bensin, dimana etanol dipilih karena memiliki nilai oktan tinggi dan emisi yang lebih rendah dibandingkan bensin. Namun, penggunaan etanol memerlukan beberapa penyesuaian konfigurasi mesin yang satu diantaranya adalah penyesuaian pada sistem katup. Dipilihnya kekakuan pegas karena pegas katup sangat berpengaruh terhadap laju massa pemasukkan campuran udara-bahan bakar kedalam silinder.
Tiga jenis pegas katup dengan kekakuan berbeda telah diuji yang hasilnya adalah sebagai berikut: pegas K1 = 1,7 kg/mm, pegas K2 = 2,2 kg/mm, dan pegas K3 = 2,7 kg/mm. Pengujian dilakukan menggunakan metode variable speed dengan perangkat dynotest. Parameter yang dianalisis meliputi daya (P), torsi (T), Brake Mean Effective Pressure (BMEP), Bake Specific Fuel Consumption (BSFC), Efisiensi Termal, serta emisi gas buang.
Hasil pengujian menunjukkan bahwa pegas katup dengan K1= 2,7 kg/mm memberikan kinerja terbaik meskipun perbedaannya kecil, Daya = 3,54 HP, Torsi= 7,67 N.m, BSFC= 0,00019 Kg/W.h, BMEP= 771,9 kPa, efisiensi termal = 42,9% namun menghasilkan emisi CO= 1,8% dan HC=3798 ppm yang lebih tinggi dibanding kedua pegas yang lain. Pegas dengan K2 = 2,2 kg/mm menunjukkan efisiensi termis yang baik = 36,5 %. Sementara itu, pegas K1 = 1,7 kg/mm menghasilkan efisiensi termal tertinggi pada rpm menengah, namun kurang stabil pada rpm tinggi yang menghasilkan emisi gas buang tinggi. Tetapi pada kondisi cruising speed (pada putaran 3500 rpm) pegas K1 = 1,7 kg/mm memiliki performa terbaik dibandingkan variasi pegas lainnya. =====================================================================================================================================
This study aims to analyze the effect of valve spring stiffness variation on the performance and exhaust emissions of a 4-stroke, single-cylinder internal combustion engine fueled by E-100 ethanol. The background of this study is based on the need for environmentally friendly alternative energy sources as engine fuel to replace gasoline, with ethanol being chosen because it has a high octane rating and lower emissions compared to gasoline. However, the use of ethanol requires several adjustments to the engine configuration, one of which is an adjustment to the valve system. The stiffness of the spring was chosen because the valve spring significantly affects the mass flow rate of the air-fuel mixture into the cylinder.
Three types of valve springs with different stiffness levels were tested, yielding the following results: spring K1 = 1.7 kg/mm, spring K2 = 2.2 kg/mm, and spring K3 = 2.7 kg/mm. The testing was conducted using the variable speed method with a dynotest device. The parameters analyzed include power (P), torque (T), Brake Mean Effective Pressure (BMEP), Brake Specific Fuel Consumption (BSFC), Thermal Efficiency, and exhaust gas emissions.
The test results show that the valve spring with K1 = 2.7 kg/mm provides the best performance, although the difference is small: Power = 3.54 HP, Torque = 7.67 N.m, BSFC = 0.00019 kg/W-h, BMEP = 771.9 kPa, ηth = 42.9%, but it produced higher emissions of CO = 1.8% and HC = 3798 ppm compared to the other two springs. The spring with K2 = 2.2 kg/mm shows good thermal efficiency = 36.5%. Meanwhile, the spring with K1 = 1.7 kg/mm achieves the highest thermal efficiency at medium RPM but is less stable at high RPM, resulting in high exhaust emissions. However, at cruising speed (3500 RPM), the spring with K1 = 1.7 kg/mm performs best compared to other spring variations.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Valve train, Valve spring, Internal Combustion Engine, Sistem Katup, Pegas Katup
Subjects:	T Technology > TJ Mechanical engineering and machinery T Technology > TJ Mechanical engineering and machinery > TJ785 Internal combustion engines. Spark ignition T Technology > TP Chemical technology > TP339 Ethanol as fuel. Biomass energy.
Divisions:	Faculty of Vocational > Mechanical Industrial Engineering (D4)
Depositing User:	Ayub Einstein Sitorus
Date Deposited:	30 Jul 2025 05:36
Last Modified:	30 Jul 2025 05:36
URI:	http://repository.its.ac.id/id/eprint/124312

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