碩士 / 國立虎尾科技大學 / 動力機械工程系機械與機電工程碩士在職專班 / 107 / During the engine operates, the temperature generated in the combustion chamber is very high, the heat would be transferred to the cylinder wall of the combustion chamber, so the cylinder block must have good heat dissipation to avoid the deformation of the metal materials.
The biggest difference between an air-cooled engine and a water-cooled engine is that the water-cooled engine can control the temperature in a certain range because the water-cooled engine has a thermostat to control the flow of cooling water, as well as a radiator, a water pump and a cooling fan to do the cooling work. However, the air-cooled engine only relies on the fins around the cylinder block to dissipate heat, i.e. relies on the generated airflow when the vehicle is moving, so it cannot control the temperature in a certain range as the water-cooled engine does, and cause the engine too hot or too cold. The engine temperature of the current air-cooled jet locomotive is relatively unstable.
At present, most of the Scooters in the market use forced air cooling, that is, a fan is installed outside the engine generator to suck in the air and take away the heat source, and the fins in the cylinder head and the cylinder block can Increase the heat dissipation area, take away more heat after the air circulates, but it is easy to cause high temperature when the engine is at high speed and high loading. The high temperature and the frictional heat generated by the engine components will increase the temperature of the piston, cylinder block, cylinder head and other components. The high temperature will easily cause the deformation of the machine parts and accelerate the wear, especially make the valve most likely to burn out, besides it cause the oil consumption and viscosity decreased which results in poor lubrication.
In this experiment, the Sym Tini 100 locomotive was used, also, we purchased and installed an additional locomotive radiator, electric fan and an electric water pump. Meanwhile, we covered the cylinder block of the original engine with an aluminum sheet. The first type was to simulate via a computer, only to wrap the first three layers of the fins. The second type was fully wrapped type, like the motorcycle shops do the refit. Both types were to let the cooling water circulate continuously in the cylinder block to test and see the results of before refit and after refit. Finally, we compared the difference between the first method and the second method. We also wanted to figure out whether the first method used can achieve the same effect in temperature control.
Before the modification, we did the simulation test with computer, the result verified that to cover the first three layers of the fins of the cylinder block could achieve the required cooling effect. This way is enough to reduce the temperature of the cylinder head, it does not need to do the modification as the locomotive shops do (using the full covered method). Furthermore, the full cladding method would make the lower half of the cylinder block being too cold, and causes too much temperature difference between the upper and lower half of the cylinder block. The much temperature difference between the parts would make the material deformed. Therefore, we retain the cooling fins of the air-cooled engine and add the water-cooled engine to improve the cooling effect of the engine.
| Identifer | oai:union.ndltd.org:TW/107NYPI1489003 |
| Date | January 2019 |
| Creators | CHEN, TSUNG-SHIN, 陳宗欣 |
| Contributors | JUAN, DAI-JIA, WENG, FENG-TSAI, 阮岱珈, 翁豊在 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 58 |
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