The Influence of Air Fuel Ratio on the Performances and Emissions of a SINJAI-150 Bioethanol Fueled Engines

In the present work, the effect of variation of air-fuel ratio on performances and emissions SINJAI-150 engine with bioethanol was conducted. Variation of the air-fuel ratio is done by setting the mass flow rate of combustion air using a supercharger. Engine performance was measured using a water brake dynamometer with a variable speed standard from 2000 to 8000 rpm at a fully open throttle condition. The results indicate that the natural intake system produces a relatively rich air-fuel ratio, with an average lambda of 0.68, so that the resulting performance is not maximum. The addition of aspirated 1 and 2 combustion air with the results in the form of average lambda at intervals of 0.8 - 1.1. On the aspirated 2, thermal efficiency increase averaged 50.32%, specific fuel consumption decrease averaged 32.74% and CO and HC emissions reduction average of 7.43 % and 25.77%

Effects of Pilot Injection Timing on The Engine Performance of A Diesel Dual Fuel Engine

The combustion process in dual fuel diesel engines occurs sequentially starting with premix burning. The premix burning starts with the ignition delay process. The presence of CNG causes the ignition delay process to become longer, thereby reducing engine performance and increasing emissions on dual fuel diesel engines. This study uses diesel engine type Diamond DI 800 with dual fuel indirect injection model system. The method used a variation of diesel pilot injection timing 110 CA, 130 CA, 150 CA, 170 and 190 CA BTDC. Testing is done with a constant engine speed of 1500 rpm and loading 500 to 3000 watts with 500-watt intervals. The results show that by advancing the diesel pilot injection timing where brake horsepower and the average effective pressure between single fuel and dual fuel is not too far as the current and voltage changes generated by the generator are not too small. While optimal thermal efficiency increased by 4.11%, while CO and HC emissions decreased respectively by 10.85%  and 8.28% at occurred at the pilot injection timing 170 CA BTDC but still under the single fuel engine

Development of Learning Media Using Flypaper in Computer and Network Engineering at SMK Negeri 1 Painan

This research aims to produce a learning media using flypaper that is valid, practical, and effective in the basics of computer network engineering and telecommunications. Learning media using flypaper is designed to increase student learning outcomes. The method in this study uses Research and Development (R and D) with the 4-D development model. The data analysis technique uses descriptive techniques to describe the validity, practicality, and effectiveness of learning media using flypaper. The results found from this development research: (1) the validity of learning media using flypaper was declared valid in media validation of 0.86>0.6 and material validation of 0.87> 0.6. (2) The practicality of learning media using flypaper from teacher responses with a value of 91.65% and student responses of 84.94% is declared very practical. (3) The effectiveness of learning media using flypaper is declared effective in improving student learning outcomes. Its concluded that learning media using flypaper is valid, practical, and effective to be utilized as a learning tool in basic network and telecommunication engineering subjects

Stress analysis of the frame of a corn harvesting tractor

The extent of existing corn land in Indonesia and the activities carried out by farmers in corn farming requires the innovation of an effective and efficient corn harvesting machine. This underlies the Research Center for Appropriate Technology located at the Faculty of Engineering, Universitas Negeri Padang to design a corn harvesting tractor that can facilitate the community in carrying out activities in the agricultural sector. The design of the corn harvester tractor consists of the harvester mechanism, the frame, the engine, and the powertrain. The frame is a crucial component of the corn harvester tractor, and its strength depends on its shape and proportions. The construction's strength of the frame must take into account both safety considerations and the structure's strength. The purpose of this study is to evaluate the frame strength of a corn harvester tractor made of steel of the ASTM A36 type. In this study, the von Mises stress that exists in the frame is used to calculate the strength of the frame of a corn harvester tractor. In numerical analysis, the chassis utilizes two tests with various load variations, namely the concentrated load and the load that is evenly distributed on the surface. The simulation results show that the frame of the corn harvester tractor can withstand the load well. The results of the stress analysis that occurs on the frame of the corn harvester tractor are that the maximum stress that occurs due to the concentrated load on the frame is 3.248 MPa. While the maximum stress that occurs due to the distributed load acting on the frame is 3.510 MPa. In addition, information was obtained that the value of the safety factor for the frame with ASTM A36 type met the component requirements that could withstand concentrated loads and distributed load

The Effects CNG Injection Timing on Engine Performance and Emissions Of A Diesel Dual Fuel Engine

Sequential combustion process on diesel dual fuel engine with compressed natural gas (CNG) fuel was complex. The problems of diesel dual fuel with CNG gas are reduced thermal efficiency and resulting in high carbon monoxide (CO) and unburned hydrocarbon (HC) emissions. The right setting between combustion air, diesel pilot fuel, and CNG gas fuel can improvement the performance and emissions. The experiment was conducted with diesel fuel conventional and dual fuel mode with CNG fuel in a single cylinder, four strokes, constant speed (1500 rpm) diesel engine type diamond DI 800. Performance parameters such as thermal efficiency and specific fuel consumption (SFC), emissions such as CO, HC, and smoke density are determined at five starts of injection timing (SOI) CNG of 700CA, 900CA, 1100CA, 1300CA, dan 1500CA ATDC with ECU programmable of Vemstune software. The results indicated that retarded CNG injection timings improved engine performance and emissions diesel dual fuel. Start of CNG injection timing optimization at 1300CA ATDC with increased thermal efficiency 14,35% and decreased specific fuel consumption (SFC) 8,83 % . in addition, it decreased CO emissions 21,35%, HC emissions 17,93%, and PM emissions lower 34,98%. However, engine performance diesel dual fuel lower than a conventional diesel engine

Pengaruh Metode Diskusi Menggunakan Aplikasi Zoom Terhadap Hasil Belajar Mahasiswa

Abstract The purpose of this study is to find out the influence of discussion methods using zoom applications during the covid-19 pandemic on the results of learning brake steering courses and suspensions in the Department of Automotive Engineering Faculty of Engineering, State University of Padang. This study consisted of two sample classes, of which one class was an experimental class of 17 people and another class of 17 people as a control class. Discussion methods using zoom apps taught in experimental classes, while the control class without using the zoom-assisted discussion method, control class uses only e-learning platform as experimental class also uses. Sampling research using incidental sampling techniques. Data analysis to test hypotheses using T-test. Before the data is analyzed, conducted in advance descriptive analysis and test of analysis requirements (homogeneity test and normality test). The results prove that there is an influence of discussion methods using zoom applications on the learning outcomes of brake steering courses and suspensions. Keywords : Discussion Method, Zoom, Learning Outcomes, Covid 19 Abstrak Tujuan penelitian ini adalah untuk mengetahui pengaruh metode diskusi menggunakan aplikasi zoom pada masa pandemi covid-19 terhadap hasil belajar mata kuliah kemudi rem dan suspensi di Jurusan Teknik Otomotif Fakultas Teknik Universitas Negeri Padang. Penelitian ini terdiri dari dua kelas sampel, dimana satu kelas merupakan kelas eksperimen yang berjumlah 17 orang dan satu kelas lagi berjumlah 17 orang sebagai kelas kontrol. Metode diskusi menggunakan aplikasi zoom diajarkan pada kelas eksperimen, sedangkan kelas kontrol tanpa menggunakan metode diskusi berbantu zoom, kelas kontrol hanya menggunakan platform e-learning sebagaimana kelas eksperimen juga menggunakannya. Pengambilan sampel penelitian menggunakan teknik sampling incidental. Analisis data untuk menguji hipotesis menggunakan uji-T. Sebelum data dianalisis, dilakukan terlebih dahulu analisis deskriptif dan uji persyaratan analisis (uji homogenitas dan uji normalitas). Hasil penelitian membuktikan bahwa terdapat pengaruh metode diskusi menggunakan aplikasi zoom terhadap hasil belajar mata kuliah kemudi rem dan suspensi. Kata Kunci : Metode Diskusi, Zoom, Hasil Belajar, Covid 1

ANALISIS KEKUATAN PEGAS PRESSURE REDUCER SEBAGAI PENURUNAN TEKANAN PADA MESIN DUEL FUEL

Pressure reducer merupakan komponen utama pada conversion kit pada mesin bahan bakar ganda (duel fuel engine) yang berfungsi sebagai penurun tekanan pada bahan bakar compressed Natural gas dari tangki sebesar ± 250 bar menjadi tekanan kerja pada injektor gas sebesar ± 2 bar, sehingga menyebabkan kekurangan pasokan jumlah bahan bakar dari pressure reducer yang berpengaruh tethadap penurunan performa mesin, baik pada saat perubahan putaran mesin secara tiba-tiba maupun perubahan beban mesin. Mengatasi permasalah tersebut maka diperlukan upaya untuk meningkatkan performa pressure reducer agar lebih adaptif terhadap perubahan kondisi mesin. Salah satu upaya yang dilakukan untuk peningkatan performa tersebut adalah menambah kekuatan konstanta pegas pada area chamber stage dua pressure reducer. Penelitian ini menggunakan mesin Diamond tipe DI 800 dengan sistem dual fuel model indirect injection. Metode yang dilakukan adalah menvariasikan kekuatan konstanta pegas (25,55 N/m, 26,55 N/m, dan 27,55 N/m). Hasil terbaik didapatkan pada konstanta pegas 27,55 N/m terjadi peningkatan jumlah laju aliran gas (mass flow rate) pada saluran keluar (outlet gas pressure reducer) sebesar 7,42%. Hal ini menunjukkan terjadi peningkatan performa pressure reducer pada saat penambahan kontanta pegas pada stage duaPressure reducer merupakan komponen utama pada conversion kit pada mesin bahan bakar ganda (duel fuel engine) yang berfungsi sebagai penurun tekanan pada bahan bakar compressed Natural gas dari tangki sebesar ± 250 bar menjadi tekanan kerja pada injektor gas sebesar ± 2 bar, sehingga menyebabkan kekurangan pasokan jumlah bahan bakar dari pressure reducer yang berpengaruh tethadap penurunan performa mesin, baik pada saat perubahan putaran mesin secara tiba-tiba maupun perubahan beban mesin. Mengatasi permasalah tersebut maka diperlukan upaya untuk meningkatkan performa pressure reducer agar lebih adaptif terhadap perubahan kondisi mesin. Salah satu upaya yang dilakukan untuk peningkatan performa tersebut adalah menambah kekuatan konstanta pegas pada area chamber stage dua pressure reducer. Penelitian ini menggunakan mesin Diamond tipe DI 800 dengan sistem dual fuel model indirect injection. Metode yang dilakukan adalah menvariasikan kekuatan konstanta pegas (25,55 N/m, 26,55 N/m, dan 27,55 N/m). Hasil terbaik didapatkan pada konstanta pegas 27,55 N/m terjadi peningkatan jumlah laju aliran gas (mass flow rate) pada saluran keluar (outlet gas pressure reducer) sebesar 7,42%. Hal ini menunjukkan terjadi peningkatan performa pressure reducer pada saat penambahan kontanta pegas pada stage du

Dry air compressor for car painting quality improvement

The humidity used in the painting process greatly determines the result of painting the car body. This study aims to develop a dry air compressor that can be used to overcome car paint defects. This system consists of a 2 HP compressor engine for sucking air from the atmosphere, two air collection tubes where the first tube contains air obtained from the atmosphere and the second tube contains dry air obtained from the first tube. The inside of the first tube is given a copper coil measuring 5 mm in diameter which is connected to a 120-watt cooler while the second tube is not given a copper coil. Each tube has a diameter of 50 cm and a height of 100 cm. The addition of copper coil aims to separate air from water by means of the condensation process which is the development of this study. Testing of compressor performance is done by turning on the compressor with the exhaust valve closed. After 60 minutes, the air pressure in each tube increased from 0 Psi to 89 Psi, the humidity decreased from 52 % to 38 %, and the temperature decreased from 31.6 °C to 18.2 °C. To see the effect of cooling on the air, the exhaust valves on both tubes were opened. In the first tube there is water coming out, as much as approximately 100 ml while in the second tube there is no water coming out. The water that comes out of the first tube is caused by the condensation process that separates the air from the water and due to the influence of gravity the water falls to the bottom of the tube. The dry air contained at the top of the first tube is flowed into the second tube and is ready to be used for painting the car body. The painting results show that there are no more small holes or paint defects on the paint surfac

Karakteristik Aliran pada Saluran Udara dengan Penambahan Square dan Circular Turbulator di Dekat Silinder Sirkular Tunggal

Penggunaan silinder sirkular banyak ditemukan pada bentuk kontruksi aplikasi teknik seperti; heat exchanger, struktur penyangga anjungan lepas pantai, jembatan dermaga, sistem perpipaan dan sebagainya. Di dalam beberapa aplikasi teknik, silinder sirkular ditempatkan di dalam saluran dengan berbagai pengaturan. Penggunaan silinder sirkular di dalam saluran tentunya mengakibatkan perbedaan karakteristik aliran dan membuat bertambahnya pressure drop. Penelitian ini bertujuan melihat karakteristik aliran dengan penggunaan variasi turbulator didekat silinder sirkular. Karakteristik aliran yang di tinjau adalah pressure drop, distribusi tekanan pada silinder sirkular dan Koefisien drag pressure. Penelitian dilakukan secara eksperimen. Turbulator ditempatkan di depan dari silinder sirkular. Turbulator yang digunakan berbentuk square dan circular cylinder. Saluran udara memiliki penampang bujur sangkar dengan luas penampang 125 x 125 mm. Rasio blockage sebesar 36,4 %. Variasi posisi sudut turbulator adalah dengan sudut α = 200, 300, 400, 500, dan 600. Pengujian dilakukan pada Reynolds number 11,6 x 104 (Re berdasarkan diameter hidrolik). Hasil dari penelitian menunjukkan penggunaan square turbulator lebih efektif mereduksi pressure drop pada saluran dibandingkan circular turbulator. Variasi posisi sudut square turbulator yang efektif mereduksi pressure drop ada pada sudut α = 300. Reduksi pressure drop pada sudut ini sebesar 23,33 %. Separasi aliran pada silinder sirkular terjadi pada sudut 1100 dan koefisien drag pressure sebesar 0,62.Penggunaan silinder sirkular banyak ditemukan pada bentuk kontruksi aplikasi teknik seperti; heat exchanger, struktur penyangga anjungan lepas pantai, jembatan dermaga, sistem perpipaan dan sebagainya. Di dalam beberapa aplikasi teknik, silinder sirkular ditempatkan di dalam saluran dengan berbagai pengaturan. Penggunaan silinder sirkular di dalam saluran tentunya mengakibatkan perbedaan karakteristik aliran dan membuat bertambahnya pressure drop. Penelitian ini bertujuan melihat karakteristik aliran dengan penggunaan variasi turbulator didekat silinder sirkular. Karakteristik aliran yang di tinjau adalah pressure drop, distribusi tekanan pada silinder sirkular dan Koefisien drag pressure. Penelitian dilakukan secara eksperimen. Turbulator ditempatkan di depan dari silinder sirkular. Turbulator yang digunakan berbentuk square dan circular cylinder. Saluran udara memiliki penampang bujur sangkar dengan luas penampang 125 x 125 mm. Rasio blockage sebesar 36,4 %. Variasi posisi sudut turbulator adalah dengan sudut α = 200, 300, 400, 500, dan 600. Pengujian dilakukan pada Reynolds number 11,6 x 104 (Re berdasarkan diameter hidrolik). Hasil dari penelitian menunjukkan penggunaan square turbulator lebih efektif mereduksi pressure drop pada saluran dibandingkan circular turbulator. Variasi posisi sudut square turbulator yang efektif mereduksi pressure drop ada pada sudut α = 300. Reduksi pressure drop pada sudut ini sebesar 23,33 %. Separasi aliran pada silinder sirkular terjadi pada sudut 1100 dan koefisien drag pressure sebesar 0,62