活塞气压平衡孔对降低燃气机机油消耗量的原理分析

Analysis of Piston Pressure Balancing Hole to Reduce NG Engine Lubricating Oil Consumption

针对某柴油机改为天然气发动机后机油消耗量大幅上升问题,通过分析天然气发动机与柴油发动机工作条件的区别,在天然气发动机的活塞设计中提出增加气孔以保证活塞气压平衡的设计方法,减小缸内负压以减少机油的吸入量,有效降低了机油消耗量。更改前后的发动机机油消耗量试验结果表明:标定转速全负荷下机油燃油消耗比由0.400%降至0.048%,降低效果明显。

A type of diesel engine was modified for natural gas operation, resulting in a considerable increase in lubricating oil consumption. Through analysing the difference between NG engine and diesel engine , a new piston design method was proposed to prevent lubricating oil from entering combustion chamber by increasing piston pressure balancing hole. This method does not change the piston structure size and elasticity, nor need it to enhance machining accuracy without any failure risk. The experimental test shows that the lubricating oil consumption （expressed as an oil-fuel ratio） has been greatly improved from 0. 400 % to 0. 048 %, so this new design method can he widely used in the piston design of other NG engines.