PERBANDINGAN PEMAKAIAN ROCKER ARM KONVENSIONAL DENGAN ROCKER ARM ROLLER BEARING PADA SEPEDA MOTOR

Roller Rocker Arm is important for transmitting signals and determining work efficiency which is the result of technological developments from ordinary rocker arms. The purpose of this study was to compare the use of conventional rocker arm with rocker arm roller on power, torque, exhaust emissions, compression on a motorcycle engine. The research method used is changing the fuel system, ignition system, changing the valve mechanism. The maximum torque on the conventional rocker arm occurs at 2995 rpm with a value of 10.92 Nm. Maximum torque decreases with increasing engine speed. The decrease in power at high speed occurs due to the influence of the volume of the fuel and air mixture which tends to decrease. The highest fuel consumption occurs at 7000 rpm engine speed in a conventional rocker arm of 0.124 kg/kWh, so the rocker arm roller is more efficient than the conventional rocker arm. Fuel consumption rocker arm roller rotation 7000 rpm 0.028 kg/kWh. While the conventional rocker arm fuel consumption at 7000 rpm 0.124 kg/kWh. Exhaust emissions, the rocker arm roller is environmentally friendly compared to the conventional rocker arm CO2 rocker arm roller only produces 5.2%, while the conventional rocker arm test results after the average CO2 value reaches 5.3%. The results of testing the two rocker arms on compression are the same at 90 Psi and 6.2kg/ from the standard size of 10-11kg/

Rancang Bangun dan Uji Performansi Alat Pembuka Katup Menggunakan Mekanisme Tuas

<p><em>The increasing number of vehicles every year provides opportunities to vehicles service. Vehicle components that often serviced or overhaul is the valve mechanism. How to remove the valve from the cylinder head generally use a manual valve remove tool. The time required to remove the valve using the tools need a long time. Effort to overcome these problems is to modify the existing valve remove mechanism. The purpose of this research is to design and test the performance of valve remove using lever mechanism. Performance test was conducted to determine the press force value to remove the valve, the percentage increase performance and time to remove the valve. The main components of the valve remove tool using the lever mechanism is frame, table, pole support, locking, hand grips, hydraulic, lever pusher and shaft sled. Testing using the valve mechanism is contained in the cylinder head Toyota Kijang 4K. The valve remove tool design has a simple form, easy to make, cheap, but has very good performance. The smallest of the press force to remove the valve is 129 N obtained at a distance of lock and poles support as far as 22 cm. The valve remove tool using the lever mechanism was design can remove the valve from the cylinder head in time 26,17 seconds/valve or 418,67 seconds to remove 16 valves on the cylinder head. This tool is able to improve the performance of manual valve remove tool screw type by 76,28%, and can improve the performance valve remove tool the pneumatic system by 65,79%.</em></p>

Instrumentation used for vibration monitoring on the supports of the tank scales of the port transshipment complex

The main thing for rotating equipment is to measure vibration, since, in the process of irreversible state change, a chain of defects always occurs and at least one of them significantly changes the vibration of the equipment. Using tank scales for static equipment, the vibration measuring makes it possible to determine the actual values of the levels and compare them with the maximum permissible values set by the manufacturer or regulatory documents. Also, the measurement of vibration levels in the time signal allows determining resonant frequencies at which vibration levels significantly increase due to the coincidence of the natural frequencies of the equipment with external workers, which can lead to increased loads on the supporting metal structures, suspended equipment and subsequently to fatigue destruction of the latter. Results of the work: the excess of the measured vibration levels on the supports of the hopper scales No. 28.1 was recorded by vibration acceleration in pt.11 (longitudinal direction) from twelve measurements; the excess of the measured vibration levels on the supports of the hopper scales No. 28.2 was not recorded, but increased levels of vibration speed were observed in pt. 11 and pt. 12; excessive vibration levels at the same measurement points on different scales may indicate that it is necessary to conduct a survey of the operation of the valve mechanism for smooth running and to monitor the condition of the metal structure under the fourth supports; it is recommended to perform a repeated measurement of the vibration of the hopper scales after inspection and repair of the structures of the scales.

A Study to Investigate the Effect of Valve Mechanisms on Exhaust Residual Gas and Effective Release Energy of a Motorcycle Engine

The purpose of this study was to investigate the effect of valve mechanisms on the exhaust residual gas (ERG) and effective release energy (ERE) of a motorcycle engine. Here, a simulation model and the estimation a new valve mechanism design is presented. An AVL-Boost simulation model and an experiment system were established. The classical spline approximation method was used to design a new cam profile for various valve lifts. The simulation model was used to estimate the effect of the new valve mechanism designs on engine performance. A new camshaft was produced based on the research data. The results show that the engine obtained a maximum engine brake torque of 21.53 Nm at 7000 rpm, which is an increase of 3.2% compared to the engine using the original valve mechanism. In addition, the residual gas was improved, the maximum engine effective release energy was 0.83 kJ, the maximum engine power was 18.1 kW, representing an improvement of 7.2%, and the air mass flow was improved by 4.97%.

Camshaft Loosening Diagnosis on the Basis of Generalised Force Recognition at the Centre of Gravity of an Engine

A valve mechanism supports the working process of an engine cylinder, and a camshaft is a key component required to open and close a valve. When a camshaft loosens, the balance of the engine disrupts. In the meanwhile, the generalised force at its centre of gravity (CG) alters. This study proposed a novel technique to detect camshaft loosening based on recognising the generalised force at the CG of the engine. We conducted Hanning windowed interpolation of discrete spectra to extract the precise phase and amplitude by utilising the acceleration signals at the engine cylinder and mounts and cylinder head. We then accurately computed the generalised force at the CG. Finally, we accurately extracted the camshaft loosening features by analysing the main harmonic orders for the generalised force. As indicated by simulations, our method can be used to effectively detect combustion engine faults involving camshaft loosening.

Functional aspects of the Eustachian tube by means of 3D-modeling

The extent of dysfunction of the Eustachian tube (ET) is relevant in understanding the pathogenesis of secondary otological diseases such as acute or chronic otitis media. The underlying mechanism of ET dysfunction remains poorly understood except for an apparent genesis such as a nasopharyngeal tumor or cleft palate. To better describe the ET, its functional anatomy, and the biomechanical valve mechanism and subsequent development of diagnostic and interventional tools, a three-dimensional model based on thin-layer histology was created from an ET in this study. Blackface sheep was chosen as a donor. The 3-D model was generated by the coherent alignment of the sections. It was then compared with the cone-beam computed tomography dataset of the complete embedded specimen taken before slicing. The model shows the topographic relation of the individual components, such as the bone and cartilage, the muscles and connective tissue, as well as the lining epithelium with the lumen. It indicates a limited spiraling rotation of the cartilaginous tube over its length and relevant positional relationships of the tensor and levator veli palatine muscles.

Matters Not That Trivial: Damage to the “Safety-Valve” Mechanism in Civil Justice and the Rise of the Boxer Movement in the Late Qing Period

Litigation in rural China under the Qing involved “trivial matters” 细事 over marriage, land transactions, debt, theft, and so on. “Going to court” 打官司, as a regular means of resolving such disputes, functioned as a “safety valve” in maintaining social order, while the mishandling of civil disputes by local magistrates and prefects often had severe consequences. After 1860, Western missionaries became increasingly active in rural North China under the system of unequal treaties. Their arrogance and interference with lawsuits by providing local converts with judicial protection caused damage to the safety valve and disgruntlement among the victims of their abuses. It was the growing enmity toward the missionaries that led to rampant violence by the Boxers around 1900.