Modifikasi Mesin Pengupas Kulit Pinang Kering

Due to the weaknesses of some existing areca peelers, some modifications were made. Modifications were made to the gear stripper, the addition of the inlet funnel, the gear stripper cover, and the exit funnel. The purpose of this modification of the design of the areca nut peeling machine is to make it easier for areca-producing farmers to peel their skin. Engine design specifications, using a 1/2 HP motor with a speed of 1500 rpm, 2-inch, and 10-inch pulleys, and a capacity of 5.16 kg/hour. The result of this modification is stated to be able to perform stripping with a large capacity. This machine is expected to be able to meet the needs of manual areca nut peelers to increase productivity.

Multibody analysis of the opposed-piston aircraft engine vibrations

One of the characteristic features of piston engines are vibrations caused by the pistons moving in the cylinders. During the engine design process, it is necessary to determine the level of vibration that can occur in the engine. This is especially important for aircraft engines. Due to the minimization of the weight of the aircraft, it is necessary to limit the factors that may cause damage to the structure. One of these factors is engine vibration, which can cause resonance and, consequently, a dangerous stress concentration. Long-term action of variable loads may also lead to the formation of fatigue cracks. The article presents the results of a multibody analysis of an opposed-piston diesel engine. It is a two-stroke three-cylinder aircraft engine. The engine has two crankshafts and six pistons that run opposite each other, but the rotation of the shafts is shifted in phase 14°. Engine vibration will also be caused by crankshafts which, to reduce weight, are not equipped with counterweights. The calculation results are presented in the form of time courses of forces and displacements on the engine supports and FFT analysis of the vibration velocity. The results show that the maximum vibration velocity is 7 mm/s and occurs at a frequency of 140 Hz, which corresponds to twice the rotational speed of the crankshafts. The results obtained from the tests allow for the selection of the flexible elements used in the real prototype engine supports.

Research of the efficiency of using the Miller cycle of an internal combustion engine

The article is devoted to the study of the possibilities of improving the technical and economic indicators of an internal combustion engine (ICE) through the use of the Miller cycle with a shortened intake. A review of scientific works on the use of the Atkinson cycle and Miller cycle in an internal combustion engine is carried out. A comparative analysis of theoretical cycles: Otto cycle, Atkinson cycle and Miller cycle is carried out. Calculated studies of the influence of the expansion ratio and the pressure increase ratio on the efficiency of the Atkinson cycle have been carried out. The ratios are presented that allow using the Miller cycle with a short inlet to obtain the same theoretical efficiency of the cycle as that of the Atkinson cycle. At the same time, the implementation of the Miller cycle in a real engine design significantly exceeds the possibilities of using the Atkinson cycle. The results of the study showed that the use of the Miller cycle with a shortened intake is preferable, but it must necessarily increase the compression ratio and intake pressure through the use of boost. On the example of real data of the main parameters of the cycle, it is shown that the use of the theoretical Miller cycle can provide a significant up to 12.2% increase in the efficiency of the cycle compared to the Otto cycle. The ratios, conditions and recommendations are presented that allow the effective use of the Miller cycle with a shortened intake in a real engine design.

Performance characteristics of diesel engine using blends of Jatropha biodiesel

Jatropha is a tropical herb and can be matured in a diverse soil with low to high rainfall. It provides a chunk of the fuel supply in the transportation and energy sectors. Jatropha biodiesel implies a diesel equivalent and consist of methyl esters. It is produced through the transesterification process which is a chemical reaction of jatropha oil with an alcohol in the presence of a catalyst. In the present work, the physical and chemical attributes of jatropha biodiesel were determined. Various blended samples of jatropha biodiesel with mineral diesel were used to run diesel engine to see the variation of the brake power, brake specific fuel consumption and brake thermal efficiency of engine with percentage increase of jatropha biodiesel in the mixture. It was observed that these properties remain unchanged for 5% and 10% blend of jatropha biodiesel to mineral diesel and hence its use is quite feasible without any change in engine design. This provides an edge to the countries having surplus lands in low rain areas to generate 10% of their energy resources for power generation and transport through the cultivation and growth of jatropha plants.

Fuel-Lubricant Interactions: Critical Review of Recent Work

A critical review of recent work on fuel lubricant interactions is undertaken. The work focusses on liquid fuels used in diesel and gasoline vehicles. The amount of fuel that contaminates the lubricant depends on driving conditions, engine design, fuel type, and lubricant type. When fuel contaminates a lubricant, the viscosity of the lubricant will change (it will usually decrease), the sump oil level may increase, there may be a tendency for more sludge formation, there may be an impact on friction and wear, and low speed pre-ignition could occur. The increased use of biofuels (particularly biodiesel) may require a reduction in oil drain intervals, and fuel borne additives could contaminate the lubricant. The move towards the active regeneration of particulate filters by delayed fuel post-injection and the move towards hybrid electric vehicles and vehicles equipped with stop-start systems will lead to increased fuel dilution. This will be of more concern in diesel engines, since significant fuel dilution could persist at sump oil temperatures in the range of 100–150 °C (whereas in gasoline engines the more volatile gasoline fuel will have substantially evaporated at these temperatures). It is anticipated that more research into fuel lubricant interactions, particularly for diesel engines, will be needed in the near future.

Free-Piston Engine Design and Evaluation with Different Compression Ratios

Free-piston heat engines are being examined by a number of international research groups as an option for conservative technology, as they are not limited by the movement of the crankshaft as in conventional engines. The free-piston engines are employed in applications like power generation using conventional methods. The higher compression ratios provide higher cycle efficiencies and also boost in-cylinder temperatures increasing mechanical stress, pressures, and heat transfer losses. This paper presents different in-cylinder flows by computational fluid dynamics for various compression ratios ranges from 7 to 15 and estimates were made to find best compression ratio for the optimal engine operating performance and characteristic.

Cosine

We present a self-designing key-value storage engine, Cosine, which can always take the shape of the close to "perfect" engine architecture given an input workload, a cloud budget, a target performance, and required cloud SLAs. By identifying and formalizing the first principles of storage engine layouts and core key-value algorithms, Cosine constructs a massive design space comprising of sextillion (10 36 ) possible storage engine designs over a diverse space of hardware and cloud pricing policies for three cloud providers - AWS, GCP, and Azure. Cosine spans across diverse designs such as Log-Structured Merge-trees, B-trees, Log-Structured Hash-tables, in-memory accelerators for filters and indexes as well as trillions of hybrid designs that do not appear in the literature or industry but emerge as valid combinations of the above. Cosine includes a unified distribution-aware I/O model and a learned concurrency-aware CPU model that with high accuracy can calculate the performance and cloud cost of any possible design on any workload and virtual machines. Cosine can then search through that space in a matter of seconds to find the best design and materializes the actual code of the resulting storage engine design using a templated Rust implementation. We demonstrate that on average Cosine outperforms state-of-the-art storage engines such as write-optimized RocksDB, read-optimized WiredTiger, and very write-optimized FASTER by 53x, 25x, and 20x, respectively, for diverse workloads, data sizes, and cloud budgets across all YCSB core workloads and many variants.

Fuel-Lubricant Interactions: Critical Review of Recent Work

A critical review of recent work on fuel lubricant interactions is undertaken. The work focusses on liquid fuels used in diesel and gasoline vehicles. The amount of fuel that contaminates the lubricant depends on driving conditions, engine design, fuel type and lubricant type. When fuel contaminates a lubricant, the viscosity of the lubricant will change (it will usually decrease), the sump oil level may increase, there may be a tendency for more sludge formation, there may be an impact on friction and wear, and low speed pre-ignition could occur. The increased use of biofuels (particularly biodiesel) may require a reduction in oil drain intervals, and fuel borne additives could contaminate the lubricant. The move to active regeneration of particulate filters by delayed fuel post-injection and the move to hybrid electric vehicles, and vehicles equipped with stop-start systems will lead to increased fuel dilution. This will be of more concern in diesel engines, since significant fuel dilution could still persist at sump oil temperatures in the range 100-150C (whereas in gasoline engines the more volatile gasoline fuel will have substantially evaporated at these temperatures). It is anticipated that more research into fuel lubricant interactions, particularly for diesel engines, will be needed in the near future.