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Pengaruh Tekanan Injeksi Gas Terhadap Konsumsi Bahan Bakar dan Efisiensi Termal pada Mesin Diesel Dual Fuel Dori Yuvenda; Bambang Sudarmanta; Randi Purnama Putra; Martias Martias; Erzeddin Alwi
invotek Vol 19 No 1 (2019): INVOTEK: Jurnal Inovasi, Vokasional, dan Teknologi
Publisher : Universitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (788.182 KB) | DOI: 10.24036/invotek.v19i1.349

Abstract

Penggunaan compressed natural gas (CNG) sebagai bahan bakar utama pada mesin diesel menyebabkan penurunan performa mesin terutama pada efisiensi termal. Hal ini dikarenakan peningkatan daya mesin yang dikonversi melalui proses pembakaran tidak sebanding dengan penambahan jumlah bahan bakar yang masuk ke dalam ruang bakar seiring dengan penambahan beban mesin. Tujuan dari penelitian ini adalah bagaimana mengoptimalkan tekanan injeksi gas CNG yang diinjeksikan ke dalam ruang bakar melalui port (intake manifold) dapat menurunkan konsumsi bahan bakar dan meningkatkan efisiensi termal pada mesin diesel dual fuel (DDF). Metode penelitian ini dilakukan secara eksperimen pada mesin DDF Diamond DI 800 dengan putaran konstan (1500 rpm). Variasi yang dilakukan adalah mengatur tekanan injeksi gas CNG yang masuk melalui port sebesar 1,5 bar, 2 bar dan 2,5 bar. Hasil yang diperoleh adalah pada tekanan injeksi gas CNG 2,5 bar dapat memberikan persentase subtitusi gas CNG rata rata sebesar 57,59%, sedangkan pada tekanan injeksi gas CNG 1,5 bar dapat menurunkan konsumsi bahan bakar spesifik (SFCdual) hingga sebesar 0,196 kg/HP.jam dan meningkatkan efisiensi termal rata-rata sebesar 3,57% dibandingkan dengan variasi lain, meskipun masih di bawah kondisi operasi mesin single fuel.
Perbandingan Kemampuan Pelepasan Panas Pada Alat Penukar Panas Radiator Straight Fin Jenis Circular Cylinder Tube Dengan Flat Tube Nuzul Hidayat; Ahmad Arif; Martias Martias
invotek Vol 19 No 1 (2019): INVOTEK: Jurnal Inovasi, Vokasional, dan Teknologi
Publisher : Universitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (475.087 KB) | DOI: 10.24036/invotek.v19i1.437

Abstract

Mesin mobil pasti menghasilkan panas akibat pembakaran dari bahan bakar. Disatu sisi panas ini menguntungkan jika dikendalikan dengan baik yaitu antara 700C- 900C namun sebaliknya jika panas ini tidak terkendali maka akan menimbulkan masalah. Apabila temperatur ini dibiarkan maka akan menyebabkan mesin menjadi overheating sehingga bisa membuat kerusakan pada komponen-komponen mesin. Dalam hal ini perlu solusi untuk menjaga mesin tetap dalam tempertur kerja dengan cara melengkapi mesin dengan sistem pendingin. Disamping itu perkembangan dalam teknologi desain radiator saat ini sudah menciptakan radiator memiliki banya varian dan bentuk, dan yang paling umum berkembang adalah model straight fin dengan flat tube dan circular cylinder tube. Kondisi ini membuat peneliti tertarik desain yang mana yang paling bagus dalam pelepasan panas untuk mendinginkan air pendingin. Untuk itu perlu upaya untuk mengetahui kemampuan radiator secara jelas agar ini dapat membantu dalam pemilihan komponen pada sebuah mobil sehingga mesin tidak mengalami overheating atau mesin tetap menjaga temperatur kerjanya. Metode yang digunakan dalam penelitian ini adalah dengan menggunakan metode eksperimental yaitu dengan menvariasikan tipe radiator dan putaran mesin serta memberikan perlakuan yang sama terhadap benda uji. Hasil penelitian menunjukan bahwa dari semua variasi kecepatan jenis radiator yang memiliki kemampuan pelepasan panas yang baik adalah tipe flat tube dengan nilai efektifitas 0.593 dengan variasi kecepatan aliran 3.52 m/s dan 120 s. Dapat disimpulkan dari penelitian adalah radiator tipe flat tube memiliki pelepasan panas lebih baik dari tipe circular cylinder tube.
The influence of project based learning on student's intrinsic learning motivation Muslim Muslim; Hendra Dani Saputra; Muhammad Yasep Setiawan; Martias Martias; Muhammad Nasir
invotek Vol 21 No 2 (2021): INVOTEK: Jurnal Inovasi Vokasional dan Teknologi
Publisher : Universitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/invotek.v21i2.915

Abstract

The lack of total student involvement in the learning process is due to a lack of effort in finding information independently and not achieving active learning. The purpose of this study was to investigate the effect of intrinsic motivation on project-based learning in the automotive engineering education student workforce transfer system course. The method used was a quasi-experimental research design with a 2x2 factorial. The population used was students of the Automotive Engineering Department, Faculty of Engineering, Padang State University, 2020/2021 academic year. The results showed that students who applied project-based learning had higher learning outcomes than using conventional methods. This was based on the value of Fcount greater than Ftable, 7.866 > 3.34 at the 0.05 significance level. There is an interaction between learning methods and students' intrinsic motivation towards learning outcomes, this is evidenced by the value of Fcount is greater than Ftable, 7.602> 3.34 at the 0.05 significance level. There is a significant difference in student learning outcomes between project-based learning and conventional learning which has high intrinsic motivation. The final research result is that there is no significant difference in student learning outcomes between project-based learning and conventional learning which has low intrinsic motivation
Persepsi Siswa Terhadap Implementasi Kurikulum 2013 di SMK Negeri 1 Sumatera Barat Muhammad Naufal; Martias Martias
AEEJ : Journal of Automotive Engineering and Vocational Education Vol 1 No 2 (2020): AEEJ : Journal of Automotive Engineering and Vocational Education
Publisher : Universitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/aeej.v1i2.9

Abstract

This research aims to investigate the students' perception of class XI towards implementing the 2013 Curriculum at Light Vehicle Engineering Competence in SMK Negeri 1 Sumatera Barat. The type of this research is quantitative descriptive. Based on the results that have been analyzed, it can be concluded that the perception of Class XI students towards the implementation of the 2013 Curriculum at Light Vehicle Engineering Competency in SMK Negeri 1 Sumatera Barat is in the well-implemented category (65.38%). It is categorized into six indicators; Learning Model in the well-implemented category (65.38); Core Competencies in the well-implemented category (50.00%); Scientific approach in the well-implemented category (59.62%); Class organizing in the very well implemented category (67.31%); The use of infrastructure in the well-implemented category(67.31%); Evaluating in the well-implemented category (32.69%). Tujuan penelitian ini untuk mengetahui bagaimana persepsi siswa kelas XI terhadap Implementasi Kurikulum 2013 Kompetensi Keahlian Teknik Kendaraan Ringan di SMK Negeri 1 Sumatera Barat. Jenis penelitian ini adalah deskriptif kuantitatif. Berdasarkan hasil analisis dapat disimpulkan bahwa persepsi siswa Kelas XI terhadap Implementasi Kurikulum 2013 Kompetensi Keahlian Teknik Kendaraan Ringan di SMK Negeri 1 Sumatera Barat berada pada kategori terlaksana baik (65.38%), dijabarkan dalam 6 indikator yaitu Model Pembelajaran pada kategori terlaksana baik (65.38%); Kompetensi Inti pada kategori terlaksana baik (50.00%); Pendekatan Saintifik pada kategori terlaksana baik (59.62%); Pengorganisasian Kelas pada kategori terlaksana sangat baik (67.31%); Penggunaan Sarana Prasarana pada kategori terlaksana baik (51.92%); Penilaian pada kategori terlaksana baik (32.69%).
Evaluasi Workshop Penyusunan Proposal Penelitian Tindakan Kelas (PTK) Di Kota Padang Panjang Donny Fernandez; R Candra; Martias Martias; Ahmad Arif
Jurnal Pendidikan Teknologi Kejuruan Vol 2 No 4 (2019): Regular Issue
Publisher : Universitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (218.795 KB) | DOI: 10.24036/jptk.v2i4.6123

Abstract

Many can be used to improve the quality of teachers, among others, the implementation of Classroom Action Research (PTK). Quality of education will increase if teachers have an compose a pediagogic, personality, competence, and professional competency. PTK is the most appropriate step to improve the quality of learning. This quality improvement will positively affect teachers and student. For teachers, PTK is a reflective action over the learning that it does. All this time, the teacher is still considered and assumes his or her other resources out of less effort to improve the model and the learning model used. By performing the PTK, the teacher will know the actual condition that he or she faces. The workshop participants were provided with knowledge about the aspects of PTK also in the preparation of a good PTK and hope that they could provide refreshment to teachers relating to the PTK, so that the teachers could do the research as well as to solve the problem of the teaching process they lead. In addition, the objective is also to stimulate teachers to produce a written article published in the field of education. In the case of the service to the community this teacher is directly guided so as to be able to make the PTK in a separate, multi-disciplinary. From the activities undertaken by the team found a very significant improvement in terms of understanding of teachers in preparing the PTK. This is obtained from the pre test (question and answer) conducted ahead of the activity and post test post activities. Although there is a significant increase in understanding, there is still a need for teachers' independence and intuition in understanding the compilation of PTK more deeply. The community service team provides wide access for workshop participants to communicate both orally and through social networking so that the competence can be developed. In addition, the team devotion to the community also provides modules and literature that can be used as a reference in the preparation of PTK. This experimental research used survey method by distributing questionnaires to respondents with different subject expertise.The results showed that the use of ICTs in learning process has not been implemented optimally. This is caused by the low competence of teachers in the sector of information and communication technology. In addition, the lack of ICT infrastructure in schools causes a deceleration in the development of ICT-based learning models. Comprehensive improvement need to be implemented so that the development of ICT-based learnings model can be performed. The results of this study are expected to provide positive feedback to improve the quality of Indonesian education.
LAYANAN PROSES PEMBELAJARAN PADA ANAK BERKESULITAN BELAJAR Meta Silvia Novembli; Marlina Marlina; Martias Martias
Jurnal Penelitian Pendidikan Khusus Vol 4, No 1 (2015)
Publisher : Universitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (125.968 KB) | DOI: 10.24036/jupe43460.64

Abstract

Abstrak: This research discusses about the service of learning process on learning difficulties at SDN 03 Air Dingin. The purpose of this research is to describe how do the services of learning difficulties. This research uses a study of qualitative approach with accumulation the data by interview, observation, and documentation study. The research result indicates that teachers is one of the causes of learning difficulties experienced by students Therefore, it was suggested to the teachers to understand more about the students’ characteristics and the problem they encountered in the learning process.Key: learning services; learning difficulties
Upaya Menurunkan Emisi NOx Engine Diesel dengan Pengaplikasian Sistem Injeksi Bertingkat M. Yasep Setiawan; Masykur Masykur; Martias Martias; Wawan Purwanto; Ahmad Arif
Jurnal Mekanova: Mekanikal, Inovasi dan Teknologi Vol 7, No 1 (2021): April
Publisher : universitas teuku umar

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (630.328 KB) | DOI: 10.35308/jmkn.v7i1.3719

Abstract

Penelitian ini bertujuan untuk menurunkan kadar emisi gas buang NOx dari hasil pembakaran campuran bahn bakar dan udara pada engine diesel diamond di-800 dengan menggunakan bahan bakar biodiesel B20. Penelitian ini dilakukan secara eksperimental dengan melakukan modivikasi pada engine diesel Diamond di-800 sitem injeksi konvensional menjadi injeksi bertingkat atau split injection yang dikontrol secara elektronik. Pengujian dilakukan dengan kecepatan konstan 1500 rpm dan menggunakan beban elektris lampu variasi beban dengan 200 watt sampai dengan 2000 watt dengan interval 200 watt. Variasi pada sistim penginjeksian bahan bakar ke ruang bakar dengan variasi injeksi 100%-0%, injeksi 75%-25%, injeksi 50%-50%, dan injeksi 25%-75%. Hasil yang didapat dari penelitian ini adalah pengaplikasian injeksi bertingkat pada engine diesel diamond di-800 efektif untuk menurunkan emisi gas buang NOx berturut-turut injeksi 75%-25%, injeksi 50%-50%, dan injeksi 25%-75% sebesar 46%, 56% dan 45% jika dibandingkan dengan injeksi tunggal atau single injection (variasi 100%).
Body City Car Design of Two Passengers Capacity: A Numerical Simulation Study Randi Purnama Putra; Dori Yuvenda; Muji Setiyo; Andrizal Andrizal; Martias Martias
Automotive Experiences Vol 5 No 2 (2022)
Publisher : Automotive Laboratory of Universitas Muhammadiyah Magelang in collaboration with Association of Indonesian Vocational Educators (AIVE)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31603/ae.6304

Abstract

A city car is needed to overcome congestion and parking spaces in urban areas. However, currently, the body design of the city car is still experiencing problems, namely the value of the large drag coefficient, which causes an increase in fuel consumption. This study aims to design a city car body with two passengers that is more aerodynamic so as to minimize fuel use. This research method is a numerical simulation model using the ANSYS fluent students version 2021. Parameters in the form of drag coefficient values, velocity streamlines and velocity contours on the city car are aerodynamic aspects that are analyzed. The results show that the dimensions of the designed city car have a length of 2.59 m, a width of 1.6 m, and a height of 1.52 m by considering the ergonomic parameters and comfort of the user so that it fits the character of the people in Indonesia. In addition, from the independence grid analysis performed, the value of the number of meshes that have the smallest error value is obtained, namely mesh C (the number of meshes is 129,635). Mesh C has an error of 7.2%. It was found that as the velocity increases, the value of the drag coefficient (CD) produced is relatively smaller. In a city car with a velocity of 10 m/s, the drag coefficient value is 0.599, at a velocity of 20 m/s, the drag coefficient value is 0.594, and a velocity of 30 m/s is a drag coefficient value of 0.591.
Influence of Use of Non-Inverting Amplifier on Power and Torque David Yulian; Martias Martias; Dwi Sudarno Putra
MOTIVECTION : Journal of Mechanical, Electrical and Industrial Engineering Vol 1 No 1 (2019): Motivection : Journal of Mechanical, Electrical and Industrial Engineering
Publisher : Indonesian Mechanical Electrical and Industrial Research Society (IMEIRS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (440.523 KB) | DOI: 10.46574/motivection.v1i1.1

Abstract

In the automotive field there are several ways to improve motorcycle performance. One of them can be done through fuel system optimization as outlined in this article. Optimization in this case is to add a non-inverting amplifiers circuit. Based on the results of the study, obtained the maximum average power data when using a non-inverting amplifier is 17.1 HP at 10885 RPM engine speed. Data before using a non-inverting amplifier is only 14.13 HP with 10167 RPM. Power increases by an average of 2.97HP (21.02%). The highest torque when using a non-inverting amplifier is 11.55 N.m. at 7970 RPM engine speed. When not using a non-inverting amplifier, torque is 10.46 N.m at 8112 RPM engine speed. Torque increases at an average of 1.09 N.m (10.42%).
The Effect of Air Ionizers Installation on Motorcycle Performance Afdhal Zikri; Martias Martias; Toto Sugiarto
MOTIVECTION : Journal of Mechanical, Electrical and Industrial Engineering Vol 1 No 2 (2019): Motivection : Journal of Mechanical, Electrical and Industrial Engineering
Publisher : Indonesian Mechanical Electrical and Industrial Research Society (IMEIRS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (306.317 KB) | DOI: 10.46574/motivection.v1i2.2

Abstract

An air ionizer device can produce negative ion which ionizes the air, can be used for engine air induction system for improving the quality of fuel mixture that increase the engine output of power & torque. Test is done by using a dynamometer by comparing power & torque with installed air ionizer active and inactive. Data analysis technique using descriptive analysis of formula ttest with 5% of significant level. The t test results showed a significant increase in maximum power under active air ionizer conditions (tcount 5,128> ttable 4,303) with a significant level of 5%, increase 0.8 HP or 11.7% of inactive air ionizer with a value 7.2 HP to 8.0 HP. Meanwhile, the maximum torque shows an insignificant increase (tcount = 0.929 <ttable = 4,303) with a significant level of 5%, increase 0.5 Nm or 6.9% of inactive air ionizer with a value of 7.24 Nm to 7, 74 Nm.