(1) Insufficient cylinder compression pressure of mixer engine

造成汽缸压缩压力不足的原因主要有：活塞环严重磨损（活塞环严重磨损将使柴油机严重冒蓝烟）、压缩比偏小（活塞顶间隙太大或气门座圈凹入太深）或气门密封不严等。

The main causes of insufficient cylinder compression pressure are: serious wear of piston ring (serious wear of piston ring will cause serious blue smoke of diesel engine), small compression ratio (piston crown clearance is too large or valve seat ring is too deep) or valve seal is not tight.

ａ、搅拌车活塞顶间隙太大

a. The piston crown clearance of mixer is too large

如果装配柴油机时，没有严格按照要求检查并调整活塞顶间隙，或调整不当时活塞顶间隙偏大时，直接影响柴油机的压缩比进而影响汽缸压缩压力。由于压缩比变小，搅拌车zf减速机降低了汽缸的压缩压力和温度，使燃油燃烧的条件变得更加恶劣，燃油燃烧不完全、不充分，柴油机严重冒黑烟。水泥搅拌车

If the piston crown clearance is not checked and adjusted strictly according to the requirements when assembling the diesel engine, or if the piston crown clearance is too large when the adjustment is not made, the compression ratio of the diesel engine will be directly affected, and then the cylinder compression pressure will be affected. As the compression ratio becomes smaller, ZF reducer of mixer reduces the compression pressure and temperature of cylinder, which makes the condition of fuel combustion worse. The fuel combustion is incomplete and insufficient, and the diesel engine emits black smoke seriously. Cement mixer

确保活塞顶间隙的正确是装配柴油机时必须严格做到的重要事件之一。在装配柴油机时，搅拌车导轨必须将活塞顶间隙调整在技术规范要求的公差范围内。一般情况下，只要安装正确，东风大力神搅拌车活塞顶间隙在使用过程中的是不会变化的。搅拌车价格

To ensure the correct clearance of piston crown is one of the important events which must be strictly done when assembling diesel engine. When assembling the diesel engine, the piston crown clearance must be adjusted within the tolerance range required by the technical specification. In general, as long as the installation is correct, the piston crown clearance of Dongfeng Hercules mixer truck will not change in the process of use. Price of mixer truck

ｂ、气门密封不严

b. The valve seal is not tight

气门密封带严重变形或磨损，将导致气门密封不严，直接降低汽缸压缩压力和温度，使燃油燃烧不完全、不充分，导致柴油机严重冒黑烟。水泥搅拌车

Serious deformation or wear of valve sealing belt will lead to valve sealing not tight, directly reduce cylinder compression pressure and temperature, make fuel combustion incomplete and insufficient, and cause serious black smoke of diesel engine. Cement mixer

ｃ、气门座圈凹入太深

c. The valve seat insert is too deep

气门座圈长期经受燃烧高温和气门的强烈冲击，加之气门座圈底孔的铝合金性质，将使气门座圈凹入逐步增加， 使气门平面与缸盖底面之间的尺寸相对增加，相应增加了燃烧室的容积，降低了柴油机压缩比，从而降低了汽缸的压缩压力和温度，中联混凝土搅拌车导致燃油燃烧不完全、不充分，柴油机严重冒黑烟

The valve seat insert has been subjected to the high temperature of combustion and the strong impact of the valve for a long time. In addition, the aluminum alloy property of the bottom hole of the valve seat insert will make the concave of the valve seat ring increase gradually, The size between the valve plane and the bottom surface of cylinder head is relatively increased, the volume of combustion chamber is increased correspondingly, the compression ratio of diesel engine is reduced, thus the compression pressure and temperature of cylinder are reduced. The fuel combustion of Zoomlion concrete mixer is incomplete and insufficient, and the diesel engine emits black smoke seriously