Motor Diesel dipengaruhi oleh beberapa aspek operasional. Diantaranya: waktu pengi­njeksian bahan bakar (timing injection), tekanan bahan bakar (fuel pressure), dan tekanan udara yang masuk (boost pressure). Modifikasi akan dilakukan untuk mengubah parameter menggunakan piggyback. Terdapat tiga hal yang akan diteliti, yaitu mengamati perubahan pada daya dan torsi jika mengubah parameter fuel pressure, parameter injection timing, dan parameter tekanan turbo. Pengujian dilakukan meng­gunakan alat bernama On-Wheel Dynamometer untuk mengetahui daya dan torsi yang dihasilkan pada kendaraan bermotor. Unjuk Kerja Mesin Diesel dapat meningkat Daya sebanyak 8% dan torsi sebanyak 11% dengan perubahan parameter pressure fuel +20, injection timing +5°, dan parameter turbo pressure 1.2 bar.

Fuel oil is one of the important parts to support daily activities. The demand for fuel oil is increasing every year. Therefore, the search for the latest energy source is continuously conducted. Carica papaya L. seed oil is investigated as a renewable energy source replacement part of petroleum diesel fuel. C. papaya seed oil obtained through the extraction process using soxhlet method with n-hexane solvent. Then produce methylester by means of transesterification using 1 % NaOH catalyst and 20 % methanol of the weight of the oil and stirred at 400 rpm for 1 h. A mixture consisting of 10 % C. papaya seed biodiesel and 90 % petroleum diesel fuel, called CPSB-10, produces fuel properties that meet the specified standards by the Indonesian Directorate General of Oil and Gas. From the result of the performance test in a diesel test engine, the maximum brake power and brake thermal are consecutively 30.6 kW and 140.23 N m, the lowest sfc is 268 g kW–1 h–1, and the highest brake thermal efficiency is 32 %.

Bioethanol is a renewable fuel that resembles gasoline, bioethanol is produced from fermentation and distillation processes. One of the raw materials that produce bioethanol is Sorghum. Sorghum was chosen because it is superior to other plants. This study aims to analyze fermentation longtime and enzyme composition for the best composition to produce bioethanol from sorghum, and determine the quality of sorghum bioethanol. This research Sorghum  bioethanol produced with an alcohol content of 94%. The test and analysis variables used were 31 samples. The results of this study are as follows : The best fermentation time is 4 days, the enzyme and yeast variable for the most volume of alcohol is 7% yeast 5% enzyme, the enzyme and yeast variable for the highest alcohol content is 7% yeast 7% enzyme. Laboratory test results when compared with PERTAMINA's standard regulations, especially Pertalite RON 90, Several parameters have rejected the regulations. Therefore sorghum bioethanol is used as an additive for Gasoline. Sorghum bioethanol is made addictive to gasoline RON 90, namely B10 (bioethanol sorghum 10%) and B20 (bioethanol sorghum 20%). It would cause an increase in the performance of gasoline engines.

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One of the challenges in modern computational engineering is the simulation of fluid-structure interaction (FSI) phenomena where one of the crucial issues in the multi-physics simulation is the choice of stiffness model for mesh deformation. This paper focuses on the application of iteratively implicit coupling procedure on two transient FSI cases of vortex induced-vibration (VIV) that manifest oscillating flexible structures. The aim is to study various mesh stiffness models in the Laplace equation of diffusion employed within the arbitrary Lagrangian-Eulerian (ALE) methodology to handle the moving mesh. In the first case where a laminar flow interacted with a flexible splitter, it was demonstrated that a near FSI boundaries increased-stiffness model prevails to manage a large deformation of the moving structure as compared to a near volume increased-stiffness model. However, the potential technique could not be exploited to the second FSI configuration, where the effect of the turbulence of flow was included. It was found that the mesh topology near the FSI interface was collapsed. Instead of utilizing the same approach, a mesh stiffness based on a wall distance was found to be auspicious. Thus, the mesh stiffness model in the FSI simulation is case-dependent.