Diesel engines are essential for transporting heavy loads, requiring significant engine power. This study aims to evaluate the effect of adding PTT (diesel fuel conditioner) additives to Dexlite fuel, focusing on mixtures of D0, D1, and D2. Additionally, variations in fuel pre-heating and engine cooling system fluids are examined. This research employs an experimental approach with descriptive analysis. The findings indicate that the optimal torque occurs with the D2 mixture, achieving 136.57 N·m at 2267 rpm with standard coolant, 152.03 N·m at 2100 rpm with a 50%:50% fluid ratio, and 160.70 N·m at 2033 rpm with a 30%:70% fluid ratio, all without pre-heating. The optimal power values for the D2 mixture are 74.60 HP at 4600 rpm with standard fluid, 75.23 HP at 4100 rpm with a 50%:50% fluid ratio, and 78.03 HP at 4000 rpm with a 30%:70% fluid ratio, also without pre-heating. The average results show that the D1 and D2 mixtures improve torque values by 0.77% and 4.75%, respectively, and enhance power by 0.19% and 1.53% compared to pure Dexlite. In contrast, pre-heating at 50°C, 60°C, and 70°C resulted in a decrease in torque of 1.00%, 2.26%, and 3.62%, respectively, and a reduction in power of 0.56%, 2.29%, and 4.79% compared to normal temperature conditions.

The rapid evolution of technology has transformed the automotive industry, transitioning from internal combustion engines to electric vehicles (EVs) to reduce greenhouse gas emissions and dependence on fossil fuels. This study focuses on developing a body electrical system for electric motorcycles by integrating components like lead-acid batteries, pulse-width modulation (PWM) controllers, waterproof DS18B20 temperature sensors, DC-DC converters, and energy-efficient LED lighting. The system is designed to comply with Indonesia’s National Standards (SNI). Employing the 4D research methodology (Define, Design, Develop, Disseminate), the electrical system underwent rigorous validation and testing. Results highlight enhanced performance, improved energy efficiency, and effective thermal management. The integration of a temperature control system reduced the risk of overheating, ensuring safety and operational reliability. This research contributes to advancing EV technology, offering a framework for optimizing body electrical systems for electric motorcycles in compliance with safety and performance standards

Traditional learning media remain prevalent due to the limited utilization of Android-based platforms among students as an instructional tool, necessitating an update in information delivery methods. The integration of technology in teaching materials aims to address this gap. This study seeks to implement Android-based interactive multimedia using the Problem Based Learning model to enhance students learning outcomes in understanding the working principles of Shielded Metal Arc Welding (SMAW) in cognitive, affective, and psychomotor domains. The research follows the ADDIE development model, which includes Analysis, Design, Development, Implementation, and Evaluation. The study involved 72 tenth grade students from the Welding and Metal Fabrication Engineering program, divided into control and experimental groups. The findings indicate that the application of Android-based interactive multimedia significantly increased students learning interest, with an initial average score of 63.194 rising to 73.889. T-test results revealed a significant difference between pre-test and post-test scores, with a significance value (2-tailed) of p = 0.00 < 0.05 and a t-value of 6.504. The hypothesis testing confirms that the use of Android-based interactive multimedia positively influences the learning outcomes of tenth grade students in the Welding and Metal Fabrication Engineering program at SMK Negeri 1 Adiwerna. Based on these findings, it can be concluded that the implementation of Android-based interactive multimedia effectively enhances students understanding of SMAW welding principles.