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柴油机的压缩比一般为16～21,汽油机为6～7,它是气缸总容积与燃烧室容积的比值。在实际使用中,以下几种原因常使燃烧室容积增大,造成压缩比变小。 (1)气门下沉 为了防止活塞撞击气门,一般要求气门头端面低于气缸盖安装平面约1.5毫米,如果气门下陷达到2.5毫米以上,会使燃烧室容积增加。 (2)缸垫过厚 一般铜皮石棉垫的压紧厚度为2毫米左
Diesel compression ratio is generally 16 to 21, the gasoline engine is 6 to 7, it is the ratio of the total cylinder volume and the combustion chamber volume. In actual use, the following reasons often make the combustion chamber volume increases, resulting in smaller compression ratio. (1) Valve Sinking In order to prevent the piston from hitting the valve, it is generally required that the end face of the valve head be lower than about 1.5 mm from the mounting surface of the cylinder head. If the valve sag reaches 2.5 mm or more, the volume of the combustion chamber will increase. (2) Cylinder pad is too thick General copper asbestos pad compression thickness of 2 mm left