Predicted Effects of Cylinder Kit Wear on Blowby and Oil Consumption for Two Diesel Engines

Durability is very important for current diesel engines. Diesel engine manufacturers are trying to make the engines live as long as possible before overhaul. The time to overhaul for an engine is usually dictated by high oil consumption or blowby. Therefore, it is necessary to understand how wear affects the cylinder kit dynamics, oil consumption, and blowby in an engine. This paper explores the effect of power cylinder component (rings and cylinder bore) wear by using a cylinder kit dynamics model. The model predicts how wear will affect ring motion, inter-ring gas pressure, blowby, etc. The parameters studied were: liner wear, ring face wear, and ring side wear. Two different engines were modeled. The characteristics of these two engines are very different. As a result, the effects of wear are different and the corresponding durability will be different. This illustrates the need to model each individual type of engine separately. The modeling shows that top ring face wear is very significant for maintaining good oil and blowby control. Liner wear is important, but does not have as large an effect as ring wear. The effects of side wear are significant for these two cases. [S0742-4795(00)00203-9]