(a）Evaporation from liner
（b) oil blow through the ring end gap
(c)Throw--off at the top ring
(d)oil scaraping of piston top edge
Figure 7 four modes of oil consumpation in difeerernt cases
Figure 8 average oil consumption at different engine speeds
Figure 9 average oil consumption at different loads
3。2 Effect of piston ring parameters on oil consumption
The piston ring plays the role of sealing, scraping oil and conducting heat。 It directly contacts with the oil and significantly influences the cylinder oil consumption。 The effects of factors of the piston ring, such as the ring height,
the surface pressure, the radial thickness, the closed gap, the fracture surface pattern and the compatibility, on the oil consumption and lubricating effect have been studied by many researchers。 In the following part, the effects of the closed gap of the second piston ring and the elastic force of each piston ring on the oil consumption of the
cylinder are analyzed under the condition of a constant groove size of the piston ring。
3。2。1 Influence of the closed gap of second piston ring on oil consumption
In the case of large torque conditions, the effect of the closed gap of the second ring on the oil consumption is analyzed under the four modes。 The original second closed gap of the diesel engine is 0。575 mm, and it is changed to 0。300 mm, 1。000 mm, 2。000 mm。 The computation results are shown in Fig。 10。 The amount of oil blow through the opening gap of the top ring decreases with the increase of the gap, because the increased gap allows the gas in the second ring side to vent out quickly。 In the suction stroke,
the pressure difference between the upper and under surfaces of the top ring decreases and the “upstream” gas also decreases, which leads to the decrease of the sucked oil。 Meanwhile, with the gap becomes larger, the amount of gas leakage increases。 So a balanced scheme is needed。 The evaporation oil on the cylinder liner wall, the dumped oil by the top ring, and the scraped oil by the piston top land
are not changed with the variation of the gap, since theirinfluencing factors are not changed。
(a）Evaporation from liner
(b) oil blow through ring end gap
(c)Throw--off at the top ring
Figure 10 four modes of oil consumption for different second closed gap
3。2。2 Influence of elastic force of each piston ring
on oil consumption
The effects of the tangential elastic force of the piston ring on the oil consumption for the four modes are investigated under large torque condition。 Elastic forces of the three rings of the original diesel engine are changed from 30 N-30 N-75 N to 20 N-20 N-50 N, 40 N-40 N-100 N, 50 N-50 N-125 N。 The results are shown in Fig。 11。 The oil thrown off by the top ring and the oil scraped of the piston top land decrease with the increase of the elastic force, because the increased elastic force leads to the increase of the surface pressure of the cylinder liner wall, thus reducing the thickness of the oil film and the amount of oil scraped by the rings and the piston top land。 The oil 柴油机缸内润滑油消耗分析英文文献和中文翻译(7):http://www.youerw.com/fanyi/lunwen_98513.html