In the first generation of LPG kit, are called Converter and Mixer (CM), the engine power is influenced strongly by the size of mixer venturi, but this case has not been widely discussed. LPG has lower carbon content than gasoline, so it requires less air to burn. Theoretically, the amount of air to burn LPG is 46% lower than gasoline. However, in practice, the venturi area of the mixer is made from 7.5 mm2 to 10 mm2 per output hp engine. To confirm this, the mixers with venturi area of 705, 960, and 1256 mm2 are applied in Toyota 5A-FE LPG-fueled engine with Tesla A-100 LPG vaporizer. The engine performance characteristics were tested using the Hofmann Dynatest Pro chassis dynamometer and the emissions were tested using QRO-401 engine gas analyzer. The result shows that the venturi area of the mixer has a major influence on the engine power, which generates specific power characteristics. However, differences in the mixer size have little effect on emissions. This study concluded that the Toyota 5A-FE LPG-fueled engine is recommended to use a mixer with venturi area of 960 mm2 (35 mm in diameter).

In recent decades, the use of ethanol as an alternative fuel for S.I. engines has become a popular issue. This is not only due to availability and oil prices, but also to address concerns about the increase in greenhouse gas effects. However, ethanol is corrosive in a fuel tank made of metal, because it contains soluble chloride ions. Therefore, this paper presents the results of an investigation of the fuel tank corrosion rate made of metal Fe_U_100 due to the use of pure ethanol. The test was performed by PGS-120T potentiostat with the addition of NaCl in ethanol in concentrations of 5, 10, 15, 20, and 25% while the estimated corrosion rate on pure ethanol was done by regression. The estimation of the fuel tank corrosion rate through the exponential regression for the use of pure ethanol is 4,116 mpy. Then, from the assessment metrics, the fuel tank made of Fe_U_100 has corrosion resistance in the excellent category. This means no fuel tank modification or replacement is required for pure ethanol applications in S.I. engine.

The center of gravity (CoG) on the minibus is one of the fundamental parameters that affect the operation of the vehicle to maintain traffic safety. CoG greatly affects vehicle maneuverability due to load transfer between the front and rear wheels, such as when turning, braking, and accelerating. Therefore, this research was conducted to evaluate the operational safety of minibusses produced by the domestic car body industry. The case study was conducted on a minibus with a capacity of 30 passengers to be used in a mining area. Investigations on CoG were carried out based on the minibus specification data, especially the dimensions and forces acting on the wheels. Minibusses as test objects were categorized in two conditions, namely without passengers and with 30 passengers. The test results are expressed in a coordinate system (x, y, z) which represents the longitudinal, lateral, and vertical distances to the center of the front wheel axle. CoG coordinate values ​​without passengers are (2194.92; 7.11; 1327.97) mm and CoG coordinates with full passengers (30 people) are (2388.52; 13.04; 1251.72) mm. The test results show that the change in CoG at full load is not significant which indicates the minibus is safe when maneuvering under normal conditions.

Pada dasarnya kriteria frame yang baik adalah memilki kekuatan dan kekakuan yang tinggi tetapi ringan dan mempunyai ketahanan terhadap korosi. Berdasarkan kriteria tersebut digunakanlah material komposit, dimana dapat diperoleh kriteria yang lebih baik dibandingkan dengan frame baja atau alumunium, Frame dapat dibuat lebih kuat dan ringan, tetapi yang lebih penting, desainer dapat mengontrol karakteristik pengendalian dan tidak dibatasi oleh penggunaan metal. Adapun tujuan dilakukan penelitian ini adalah menganalisa kondisi optimum desain rangka sepeda dengan metode Taguchi dan analisis ANOVA. Berdasarkan hasil analisis pengolahan data dengan kondisi desain optimum yg memberikan Tegangan Von Mises (MPa) yang besar adalah : A2  B2  C3 atau yang dilakukan perhitungan dengan kondisi desain menggunakan Seat Tube Angle sebesar 72o, dengan pergeseran Head Tube 0.2 mm dan beban pengendara sebesar 90 kg. Analisis perhitungan dengan ANOVA untuk mengetahui pengaruh masing-masing faktor terhadap perhitungan Tegangan Maksimum pada sepeda berbahan komposit, yaitu : Faktor A (Seat Tube Angle) sebesar 85% memiliki pengaruh yang sangat besar, dibandingkan dengan faktor C (Beban Pengendara) sebesar 10%, selanjutnya untuk faktor B (Pergeseran Head Tube) memiliki pengaruh 1%.

No abstract

In 2015, the Indonesian government issued regulations to accelerate the implementation of integrated Light-Rail Transit (LRT) in the capital region and its surroundings. In order to ensure its operational safety, experimental work is required to test components’ strength of the manufactured LRT structures. Following the JIS 7105 standard test method, the strain and deflection of the structures were measured by vertical load, compression, rotation, and three-point load support test. The critical area estimated in the railroad structure were conducted according to the finite element method, in which strain gauges are installed in areas where the stress concentration exceeds nominal pressure, namely notches, bends, and junction areas. The result shows that the maximum stress on the LRT train structure occurs at the door, where maximum compressive strain value is -1082 μe » -75.74 MPa on the left and the maximum tensile strain value is 597 μe » 41.79 MPa at the right door. The results of fatigue load analysis represent the average stress (σm) and voltage amplitude (σa) at the coordinate system located in the Søderberg triangle. Meanwhile, the camber value with the full vertical load still has a positive value of 3.03 mm, which indicates a safe limit.

No abstract

Mesin bubut dapat dirubah kemampuan fungsinya untuk mesin penguji injection pump motor diesel.Merubah kemampuan fungsinya menjadi mesin penguji injection pump motor diesel tersebut dilakukandengan menambahkan alat berupa dudukan injection pump dan sistem bahan bakar motor diesel. Alattambahan yang dibuat terdiri atas dua bagian utama yaitu dudukan injection pump yang mempunyai fungsisebagai dudukan injection pump sehingga poros injection pump segaris dengan pencekam benda kerja danalat tambahan yang kedua yaitu dudukan sistem bahan bakar, khususnya nozel dan gelas ukur sebagaipenampung dan pengukur hasil penyemprotan nozel. Proses pengujian injection pump dilakukan denganmemberikan variasi putaran pada poros injection pump sehingga dapat terbaca volume penyemprotannozel akibat putaran poros injection pump. Modifikasi mesin bubut ini diharapkan dapat dimanfaatkan olehbengkel servis motor diesel yaitu bengkel kecil yang tidak memiliki mesin penguji injection pump danperguruan tinggi khususnya jurusan teknik mesin dan sekolah menengah kejuruan khususnya teknikkendaraan ringan dan alat berat.