| 摘要 |
The valves, particularly the exhaust valves of internal combustion engines, are damaged by high temperatures and corrosion. The cooling allows to reduce the temperature and hence corrosion. The transfer of heat to cooling water results in an energy loss, which reduces the engine efficiency. Owing to the combination of good heat conducting materials with a corrosion and temperature shield made of a bad conductor material, it is possible to reduce the heat transmission to the inside and therefore to increase the engine efficiency. The portion of heat transmitted to the inside may be conducted, by means of the good conductor material, in the stem and in the cooling water. The core and the stem remain cooler and may better comply with the requirements of heat resistance in order to reduce deformations.
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