Experimental Study Influences Changes In Compression Ratio To Performance Of Single Cylinder Otto Engine

Increasing the compression ratio is an attempt to increase the efficiency and performance of the engine. The purpose of the study was to analyze the effect of changes in the compression ratio on engine performance. Tests using a single-cylinder Otto engine by comparing the performance of an enlarged compression ratio of 9.7:1 and 10.4:1 with a standard compression ratio of 9.0:1. The result of the research is that the compression ratio of 9.7:1 produces a peak torque of 7.51 Nm at 6000 rpm, a peak power of 5.30 kW at 8000 rpm, and the lowest BSFC is 0.146 kg/kW.h at 6000 rpm. Torque and power increased by 0.09 Nm and 0.28 kW, and BSFC decreased by 0.018 kg/kW.h compared to the standard compression ratio of 9.0:1. Using a compression ratio of 10.4:1 produces a peak torque of 7.69 Nm at 6000 rpm, a peak power of 5.38 kW at 8000 rpm, and the lowest BSFC is 0.116 kg/kW.h at 6000 rpm. Torque and power increased by 0.27 Nm and 0.36 kW, and BSFC decreased by 0.030 kg/kW.h compared to the standard compression ratio of 9.0:1

Experimental Test of Ignition Timing with Programable CDI on Performance Single Cylinder Otto Engine

Ignition timing is sparking from the spark plug based on the ignition angle during the compression stroke in the combustion chamber relative to the piston position and the crankshaft angular speed. Adjusting the ignition angle is one method to optimize the combustion process in the engine. An optimal combustion process can improve engine performance and reduce fuel consumption. This study investigates optimal data from ignition angle changes using a programmable CDI. The test was performed on a single-cylinder fourstroke Otto engine with standard ignition angle variations, +3°, +6°, and +9° before TDC. The test results show that torque and power have increased while brake-specific fuel consumption has decreased. Optimal data acquisition at ignition angle of +9° with peak torque value of 6.91 Nm and peak power value of 4.80 kW, while the lowest value of specific fuel consumption is 0.234 kg/kWh, and the highest value of thermal efficiency is 36 %. From this study, it was concluded that the ignition timing could affect the engine performance

PENERAPAN TEKNOLOGI TEPAT GUNA SEBAGAI PENINGKATAN KAPASITAS MESIN PENGAYAK PASIR TIPE ROTARY DAN USAHA DUSUN TANGGALAN, KABUPATEN KARANGANYAR

The increasing of infrastructure development causing in increased demand for sand material. On the other hand, the sand still contains many other components such as gravel. The size of good sand according to the Indonesian National Standard (SNI - 03-247-2002) is natural or artificial sand produced by the stone crusher industry with the largest grain size of 5 mm. On the other hand, the lack of infrastructure of the Tanggalan vilage and the small income of the village has resulted in an uneven distribution of the regional economy. Youths and heads of the Tanggalan village see the potential to increase the village's income by making sieving businesses and providing good quality building sand. The manual sieving process takes longer, so it has an impact on the development process as well as from an economic point of view on the long construction costs. So, it is necessary to have a rotary type automatic sieving machine that has a function to separate fine sand grains or according to the criteria requested by consumers with gravel. Rotary type sieving machine with a capacity of 10 m3/hour, so it is expected to meet the demand and accelerating development process. In addition, with this tool, hamlet businesses can be formed to increase hamlet income. Key words: Business, Enhancement, National Standard, Rotary, Sand Sieve

SIMULATION-BASED ASSESSMENT KINERJA TERMAL PADA CONCENTRIC TUBE HEAT EXCHANGER

The double-pipe heat exchanger is one of the most popular heat exchanger devices. In this study, the concentric tube heat exchanger as the double pipe heat exchanger device was simulated with ANSYS code FLUENT. The simulation was done by based on the Reynolds number variation from 400010.000 using the method of co-current and counter flow. The hydrodynamic and thermal simulation results agree with the empirical correlation of the Pethukov and Dittus-Bolter equations, respectively. The friction factors of the water base fluid and nanofluid f TiO2/water f (0.1 vol.%) do not result in a significant difference in the turbulent flow regime for both co-current and counter flow. The thermal performance of TiO2/water (0.1% vol) nanofluid as indicated by the value of the heat transfer coefficient results in an increase of 6.9% for counter low flow and 6.0% for co-current flow. Meanwhile, the direction of fluid flow in the heat exchanger does not have a significant effect on its thermal performance

WAHANA PAPAN SELUNCUR SEBAGAI SARANA INTERAKSI ANAK DENGAN DUNIA LUAR

Abstrak: Taman bermain merupakan lingkungan yang dirancang khusus untuk menyediakan kesempatan bermain, belajar, dan berinteraksi bagi anak-anak. Taman bermain tidak hanya merupakan tempat hiburan semata, tetapi juga berperan sebagai ruang pendidikan yang mendukung perkembangan fisik, kognitif, sosial, dan emosional anak-anak. Pengabdian ini bertujuan untuk merancang desain wahana bermain papan seluncur yang dirancang dengan mempertimbangkan faktor keselamatan, kenyamanan, dan pengembangan anak di Taman Mekarsari Desa Kaligentong, Kecamatan Gladagsari, Kabupaten Boyolali. Papan seluncur merupakan sebuah wahana dengan bentuk seperti seluncuran yang difungsikan sebagai sarana anak-anak untuk berinteraksi pada lingkungan luar. Metode yang digunakan pada pengabdian ini berupa deskriptif kualitatif yang dilakukan melalui tahapan wawancara dan observasi. Pengabdian ini merupakan kolaborasi antara dosen dan mahasiswa Program Studi Teknik Mesin, Universitas Sebelas Maret, Surakarta dengan Kelompok Tani (PokTan) Desa Kaligentong, Gladagsari, Boyolali sebagai pengelola Taman Mekarsari. Evaluasi yang dilakukan untuk wahana bermain ini yaitu dengan melakukan simulasi percobaan papan seluncur secara langsung. Dari kolaborasi ini didapatkan hasil berupa desain papan seluncur yang kokoh dan dibuatnya wahana bermain papan seluncur yang aman dan nyaman di Taman Mekarsari. Diharapkan dengan adanya wahana bermain ini dapat mendorong interaksi sosial dan pengembangan keterampilan anak-anak sehingga dapat meningkatkan kualitas hidup dengan memberikan kesempatan bermain dan belajar secara menyeluruh.Abstract:  Playgrounds are environments specifically designed to provide opportunities for children to play, learn and interact. Playgrounds are not only places of entertainment, but also act as educational spaces that support children's physical, cognitive, social, and emotional development. This service aims to design a skateboard playground that is designed by considering safety, comfort, and child development factors at Mekarsari Park, Kaligentong Village, Gladagsari District, Boyolali Regency. Papan seluncur is a vehicle with a shape like a slide that functions as a means for children to interact with the outside environment. The method used in this service is descriptive qualitative which is carried out through interviews and observations. This service is a collaboration between lecturers and students of the Mechanical Engineering, Universitas Sebelas Maret, Surakarta with the Farmer Group (PokTan) of Kaligentong Village, Gladagsari, Boyolali as the manager of Mekarsari Park. The evaluation carried out for this playground is by simulating the papan seluncur experiment directly. From this collaboration, the results were obtained in the form of a sturdy papan seluncur design and the creation of a safe and comfortable papan seluncur playground in Mekarsari Park. It is hoped that this playground can encourage social interaction and skill development of children to improve the quality of life by providing comprehensive play and learning opportunities. 

Manajemen Energi pada Hybrid Solar Vehicle Type Seri-Paralel

Abstract. Dalam makalah ini, studi tentang manajemen energi pada kendaraan Hybrid Solar Vehicle (HSV) disajikan. Sistem yang diusulkan terdiri dari lima komponen konversi energi utama yaitu mesin pembakaran dalam, motor listrik, generator listrik, baterai, dan fotovoltaik. Sistem manajemen energi pada kendaraan surya hibrida bertujuan untuk memilih mode operasi terbaik yang sesuai dengan kondisi daya berkendara dan status pengisian baterai (SOC). Dalam studi ini, sistem manajemen energi yang diusulkan menerapkan persamaan keseimbangan energi tertentu untuk setiap mode pengoperasian kendaraan sebagai dasar dari algoritma pengambilan keputusan. Algoritma tersebut kemudian disimulasikan pada model sistem kendaraan surya hybrid seri-paralel untuk mengetahui daya yang disuplai oleh setiap komponen, konsumsi bahan bakar kendaraan, dan efisiensi setiap komponen.Simulasi dilakuan menggunakan lima driving cycle yang berbeda dan masing masing dengan kondisi awal SOC yang bervariasi (SOC=0,9;0,7;0,41;0,2) Hasil penelitian menunjukkan bahwa skenario manajemen energi dapat berjalan pada semua kondisi simulasi tersebut. ICE dapat diatur beroperasi konstan pada efisiensi tertinggi sekitar 0,33. Generator juga dapat diatur selalu beroperasi pada efisiensi tertingginya sekitar 0,85. Konsumsi bahan bakar mesin pembakaran dalam pada kendaraan surya hibrida sekitar pada kondisi awal SOC 0,9 dan 0,7 jauh lebih rendah dibanding kendaraan kovensional. Pada kondisi awal SOC 0,4 kondisi konsumsi bahan bakar hampir berimbang. Pada kondisi awal SOC 0,2 konsumsi jauh lebih tinggi karena ICE-GE berfungsi ganda yakni untuk memenuhi kebutuhan daya berkendara dan mengisi baterai. Kontribusi fotovoltaik pada tiap siklus cukup signifikan sekitar 30%-39%. ================================================================================================================= Abstract. In this paper, a study on energy management in hybrid solar vehicles is presented. The proposed system consists of five main energy conversion components, namely an internal combustion engine, an electric motor, an electric generator, a battery, and a photovoltaic. The energy management system in hybrid solar vehicles aims to select the best operating mode according to the driving power conditions and battery charge status (SOC). In this study, the proposed energy management system applies a specific energy balance equation for each vehicle operating mode as the basis of the decision making algorithm. The algorithm is then simulated in a series-parallel hybrid solar vehicle system model to determine the power supplied by each component, vehicle fuel consumption, and the efficiency of each component. The simulation is carried out using five different driving cycles and each with varying initial SOC conditions ( SOC = 0.9; 0.7; 0.41; 0.2) The results show that the energy management scenario can work in all of these simulation conditions. ICE can be set to operate constant at the highest efficiency of about 0.33. The generator can also be set to always operate at its highest efficiency around 0.85. The fuel consumption of internal combustion engines in solar hybrid vehicles with SOC initial conditions of 0.9 and 0.7 is much lower than conventional vehicles. In the initial conditions, SOC 0.4, the fuel consumption condition is almost balanced. In the initial condition, SOC 0.2, the consumption is much higher because ICE-GE has a dual function, namely to meet the driving power needs and charge the battery. Photovoltaic contribution in each cycle is significant, which is around 30%-39%.

Numerical and Experimental Investigation of Air Cooling for Photovoltaic Panels Using Aluminum Heat Sinks

An increase in the operating temperature of photovoltaic (PV) panels caused by high levels of solar irradiation can affect the efficiency and lifespan of PV panels. This study uses numerical and experimental analyses to investigate the reduction in the operating temperature of PV panels with an air-cooled heat sink. The proposed heat sink was designed as an aluminum plate with perforated fins that is attached to the back of the PV panel. A comprehensive computational fluid dynamics (CFD) simulation was conducted using the software ANSYS Fluent to ensure that the heat sink model worked properly. The influence of heat sinks on the heat transfer between a PV panel and the circulating ambient air was investigated. The results showed a substantial decrease in the operating temperature of the PV panel and an increase in its electrical performance. The CFD analysis in the heat sink model with an air flow velocity of 1.5 m/s and temperature of 35°C under a heat flux of 1000 W/m2 showed a decrease in the PV panel’s average temperature from 85.3°C to 72.8°C. As a consequence of decreasing its temperature, the heat sink increased the open-circuit photovoltage (VOC) and maximum power point (PMPP) of the PV panel by 10% and 18.67%, respectively. Therefore, the use of aluminum heat sinks could provide a potential solution to prevent PV panels from overheating and may indirectly lead to a reduction in CO2 emissions due to the increased electricity production from the PV system