Hasan Maksum

Optimizing combustion parameters by incorporating alternative fuels and modifying the engine's mechanical properties is essential to improving the thermal efficiency and performance of modern internal combustion engines. This study examines the impact of HHO gas utilization, variations in compression ratios, various types of spark plugs, and ethanol gasoline blends on the torque and other characteristics of a 4-stroke fuel-injected single cylinder engine. Hydrogen is generated via electrolysis and used as a supplementary fuel. The Taguchi method was employed to create tests involving four variables: HHO percentage, compression ratio, spark plug type, and ethanol mixture. Testing occurred at 5000 RPM under a load of 1800 Watts. The findings indicated that the combination of 20% HHO, a compression ratio of 16.9:1, platinum spark plugs, and E-80 ethanol yielded optimal engine performance, with thermal efficiency reaching 60% at 7500 rpm. Moreover, the results of deposit content analysis after 50 hours of operation indicated that the ideal design produced fewer deposits than RON 92 gasoline.

Rendahnya minat dan hasil belajar siswa pada materi teknis seperti Motor Starter di SMK mendorong perlunya inovasi media pembelajaran yang lebih interaktif dan kontekstual. Augmented Reality (AR) muncul sebagai teknologi yang mampu menciptakan pengalaman belajar imersif dengan menggabungkan objek virtual ke dalam lingkungan nyata secara real-time. Penelitian ini bertujuan untuk menganalisis secara sistematis pengaruh media pembelajaran berbasis AR terhadap minat dan hasil belajar siswa berdasarkan publikasi ilmiah periode 2020–2025. Penelitian menggunakan metode Systematic Literature Review (SLR) dengan pedoman PRISMA 2020. Pencarian dilakukan pada database Scopus menggunakan enam kombinasi kata kunci berbasis AR dan pembelajaran; dari 1.111 artikel yang teridentifikasi, diperoleh 50 artikel yang memenuhi kriteria inklusi melalui proses screening dan penilaian eligibility full-text. Hasil analisis menunjukkan bahwa: (1) implementasi AR secara konsisten meningkatkan hasil belajar siswa dengan effect size sedang hingga tinggi (d = 0,41–1,24); (2) AR efektif meningkatkan motivasi dan minat belajar melalui pengalaman belajar yang interaktif dan imersif; (3) efektivitas AR dipengaruhi oleh pendekatan pedagogis, desain aplikasi, dan karakteristik siswa. Penelitian ini menyimpulkan bahwa AR merupakan media pembelajaran yang efektif untuk meningkatkan minat dan hasil belajar siswa di berbagai jenjang pendidikan, dan berpotensi besar untuk diterapkan pada pembelajaran Motor Starter di SMK.

This study integrates an Augmented Reality (AR) simulation into a Project-Based Learning–Troubleshooting (PjBL-T) model for an automotive chassis course to strengthen students’ diagnostic and problem-solving skills. Using a developmental research design, we applied a 4D sequence—Define including needs analysis and task/specification mapping, Design including AR storyboard, PjBL-T syntax alignment, instrument blueprints, Develop including prototype builds, expert validation, small-group try-out, and Disseminate including field implementation and refinement. Participants were purposively sampled from intact classes enrolled in the course which are one PjBL-T+AR cohort and a comparison cohort using conventional media. The AR module using Unity engine with Vuforia SDK delivered manipulable 3D models of suspension, steering, and braking systems and included parameterized virtual-fault scenarios for guided troubleshooting. Data were gathered with a diagnostic-accuracy rubric, a problem-solving performance rubric, a concept comprehension test, and a student engagement survey (Likert). Analyses included content validity, reliability checks, and inferential tests. Results show higher engagement, deeper conceptual understanding, and improved diagnostic accuracy for the PjBL-T+AR cohort relative to baseline and the comparison group. The model is scalable because it (i) runs on widely available Android smartphones/tablets with offline assets, (ii) uses modular, reusable fault libraries and glTF/FBX 3D packages that map directly to each PjBL-T stage, and (iii) provides templated authoring and Learning Management System (LMS) integration, enabling rapid replication across courses and institutions without specialized labs.

This study aimed to examine effect of injection timing on the use of biodiesel fuel from waste cooking oil processed with ultrasonic transesterification technology on exhaust emissions of Diesel engine. Several variations of injection timing were applied to evaluate their impact on exhaust gas characteristics and engine emissions. Engine was run at a constant speed of 2400 rpm with standard injection timing (17° CA bTDC), advanced at an angle of 3° and 6° CA (20° and 23° CA bTDC), followed by retardation at 3° and 6° CA (14° and 11° CA bTDC). The results showed that the standard injection timing of 17° CA bTDC provided optimal performance with an exaust gas temperature (EGT) of approximately 250 °C at B10. Advancing injection timing increased the EGT to 320 °C but reduced CO and UHC emissions by 11.11% and 26.30%, respectively. However, there was a significant increase in smoke opacity emissions and NOx by 14.58% and 31.1%, respectively. The retardation in injection timing decreased EGT to 220 °C as well as increased CO, UHC, and smoke opacity emissions, with NOx rising by 10.4%. These results showed that ultrasonic transesterification technology produced high quality biodiesel with better combustion characteristics. Meanwhile, increasing biodiesel content (B20-B100) tended to cause a rise in NOx emissions due to higher oxygen content.

The purpose of this study was to determine the differences in torque, power, and specific fuel consumption produced by four-stroke motorcycles with different compression ratios and using different fuels. This study used an experimental method. The results of the study at a standard compression ratio of 9.6:1, the highest torque was 12.17 Nm using Pertamax Plus fuel, while the highest power was 5.77 Kw using Pertamax Plus fuel, and the lowest specific fuel consumption was in the use of Pertamax Plus fuel at 0.1192 Kg/kWh. At a compression ratio reduced to 8.9:1, the highest torque was 9.38 Nm using Pertamax Plus fuel, while the highest power was 4.03 Kw using Pertalite and Pertamax Plus fuel, while the lowest specific fuel consumption was in the use of Pertamax Plus fuel at 0.1537 Kg/kWh. When the compression ratio is increased to 10.3:1, the highest torque is 20.19 Nm using Pertamax Plus fuel, while the highest power is 6.67 Kw using Pertamax Plus fuel, while the lowest specific fuel consumption is when using Pertamax Plus fuel at 0.1258 Kg/kWh. ABSTRAK Tujuan penelitian adalah untuk mengetahui perbedaan torsi, daya dan konsumsi bahan bakar spesifik yang dihasilkan dari sepeda motor empat langkah dengan perbandingan kompresi berbeda dan menggunakan bahan bakar yang berbeda. penelitian ini menggunakan metode eksperimental. Hasil penelitian pada perbandingan kompresi standar 9,6:1 torsi tertinggi sebesar 12,17 Nm menggunakan bahan bakar pertamax plus, sedangkan daya tertinggi sebesar 5,77 Kw menggunakan bahan bakar pertamax plus, dan konsumsi bahan bakar spesifik terendah pada penggunaan bahan bakar pertamax plus 0,1192 Kg/kWh. Pada paat perbandingan kompresi diturunkan 8,9:1 torsi tertinggi sebesar 9,38 Nm menggunakan bahan bakar pertamax plus, sedangkan daya tertinggi sebesar 4,03 Kw menggunakan bahan bakar pertalite dan pertamax plus, sedangkan konsumsi bahan bakar spesifik terendah pada penggunaan bahan bakar pertamax plus 0,1537 Kg/kWh. Pada saat perbandingan kompresi dinaikkan 10,3:1 torsi tertinggi sebesar 20,19 Nm menggunakan bahan bakar pertamax plus, sedangkan daya tertinggi sebesar 6,67 Kw menggunakan bahan pertamax plus, sedangkan konsumsi bahan bakar spesifik terendah pada penggunaan bahan bakar pertamax plus 0,1258 Kg/kWh.

The integration of Artificial Intelligence (AI) in vocational education opens up transformative opportunities to develop 21st-century skills, especially critical thinking and problem-solving, which are key competencies for prospective professionals in the automotive sector. This study examines the effectiveness of using AI (Claude and Pollo AI) through the Project-Based Learning (PjBL) model in improving the critical thinking and problem-solving skills of automotive engineering students in the Vehicle Motion Mechanics course. The study, using a pre-experimental intact group comparison design, involved 37 third-semester students, consisting of an experimental group () and a control group (). The experimental group learned using AI-based PjBL, while the control group received conventional Discovery Learning. Data were collected through validated analytical rubrics and analyzed using an independent samples t-test and effect size. The results showed that the experimental group obtained a much higher critical thinking score (M = 82.45; SD = 6.23) compared to the control group (M = 71.33; SD = 7.89), . Similar improvements were also found in problem-solving skills (M = 84.12; SD = 5.87 vs. M = 69.78; SD = 8.45), , which indicates a strong practical impact. These findings confirm that the integration of AI through PjBL effectively strengthens critical thinking and problem-solving skills in automotive vocational education, while providing empirical evidence to drive technology-based engineering learning transformation.

This study aims to develop a mobile air conditioning (AC) trainer as an innovative learning medium to enhance students’ understanding, interest, and performance in automotive AC systems. The research adopted the Research and Development (R&D) approach using the 4D model, which consists of the Define, Design, Develop, and Disseminate stages. Validation was conducted by media and material experts, yielding Aiken’s V coefficients of 0.93 and 0.96, respectively, categorized as “Valid.” The practicality test involving teachers and students obtained mean scores of 94.20% and 96.24%, categorized as “Highly Practical.” The effectiveness of the developed trainer was evaluated through pretest and posttest data, resulting in an N-Gain score of 0.69, which indicates a “High” level of improvement. These findings demonstrate that the developed AC trainer is valid, practical, and effective as instructional media in vocational education, particularly in enhancing students’ academic achievement in automotive air conditioning systems.

This study addresses the urgent need to bridge the competency gap between vocational education graduates and the rapidly evolving demands of the modern automotive industry, particularly in the increasingly complex electronic fuel injection (EFI) systems. Conventional learning approaches have proven insufficient in equipping students with the necessary technical and non-technical skills to adapt to current technologies. Therefore, this study aims to develop and validate a mobile-based EFI simulator integrated with QR code technology, enabling interactive visualization of the components, data flow, operational processes, and diagnostic procedures of the EFI system in an easily understandable manner. The simulator’s effectiveness is further evaluated through its integration within the Problem-Based Teaching Factory (PBTF) model to enhance students’ 4C skills: collaboration, communication, creativity, and critical thinking. Employing a Research and Development (R&D) approach with the 4-D model (Define, Design, Develop, Disseminate), the study involved 50 Automotive Engineering students at FT-UNP, divided into experimental and control groups. Validity analysis using SEM-PLS confirmed high validity of the simulator, especially in visualization aspects, while effectiveness testing showed that the experimental group using the simulator scored significantly higher in 4C skills than the control group. These results confirm that integrating the Mobile QR-EFI Simulator within the PBTF model significantly improves students’ critical and creative skills, bridges the gap between theory and practice in vocational automotive education, and meets the demand for interactive learning tools aligned with modern industry developments.

This systematic literature review addresses the limited empirical evidence on integrating e-modules and Project-Based Learning (PjBL) in application-intensive engineering courses, particularly Powertrain Systems. Following PRISMA 2020 guidelines, a Scopus search (2015–2025) identified 600 articles, of which 18 high-quality empirical studies were selected through four screening phases. Meta-aggregation of pre–post data indicates substantial learning gains across domains: cognitive (+24.3%, d = 1.42), affective (+22.7%, d = 1.28), and psychomotor (+25.4%, d = 1.51). Effective e-module features include interactive video tutorials, virtual simulations, and industry-based case studies. Team-based PjBL projects lasting 6–8 weeks emerged as the most suitable format for undergraduate settings. Key challenges involve high development workload, infrastructure limitations, and insufficient faculty readiness. Based on synthesized evidence, this review proposes a structured five-module framework for Powertrain Systems that integrates progressive PjBL complexity, simulation-supported learning, authentic industry contexts, and diversified assessment strategies to enhance learning outcomes.

This study systematically examines the factors that affect students' job readiness and satisfaction in engineering education through a comprehensive analysis of industry support, certification programs, and academic engagement. The Industrial Revolution 4.0 era has created a significant skills gap between graduate competencies and industry needs, demanding innovative approaches in the preparation of work-ready graduates. Through the Systematic Literature Review (SLR) which follows PRISMA's guidelines for articles obtained from the ScienceDirect database during the period 2017-2024, this study integrates evidence from multiple theoretical frameworks including experiential learning theory, social cognitive theory, and human capital theory. Of the 800 articles identified through ScienceDirect's database search, after going through a rigorous PRISMA selection process with quality assessment using the Mixed Methods Appraisal Tool (MMAT), 185 high-quality articles were successfully selected and analyzed in depth. Key findings show a significant positive relationship between industry-university collaboration, the implementation of professional certification programs, and active academic involvement to improving job readiness and student satisfaction. The analysis revealed that the implementation of industrial internship programs (94% effectiveness, satisfaction score 4.6/5.0), industry-specific competency certification (satisfaction rating 4.4/5.0), and extracurricular activities such as capstone projects and engineering competitions can significantly increase employability. Nonetheless, systemic challenges such as curriculum gaps with industry needs (identified in 68.1% of studies), limited faculty experience in industry (53% of studies), and infrastructure limitations (47% of studies) remain structural barriers that require comprehensive solutions. This research provides an evidence-based framework for transforming technical education toward more industry-relevant, student-centered approaches and provides actionable recommendations for educational practitioners, policymakers, and industry partners.