Simulation of the cylinder bore distortion and effect on the sealing capacity of the ringpack

Abstract

One of the several losses of a combustion chamber is the gas leakage toward the crankcase due to imperfect sealing of the rings, it is commonly known as blow-by and it affects efficiency and emissions. One important factor affecting it is the distorted cylinder bore. The paper describes the equations that rule the blow-by phenomenon in terms of ring and gas dynamics, subsequently, the bore distortion of the cylinder was obtained and its orders calculated through Fourier series. The ringpack capacity in the distorted bore cylinder was then analysed using ©Ricardo RINGPAK Solver. Order zero distortion resulted to be the most important order due to the highest amount of gas lost in the crankcase. Orders one and two didn't showed significant differences from the non-distorted bore case, while orders three and four resulted in high blow-by values, even if their magnitude of distortion was lower in comparison to other orders. The ring pack behavior showed to be affected by bore distortion and its magnitude, however, the blow by phenomenon showed to depend also on other factors in a complex manner.

Engine Speed and Load on the Sealing Capacity of a Piston Ring-Pack

“…The number of parameters affecting the sealing efficiency of a ring-pack is high. In previous works [15][16][17], authors investigated the effect of the ring gaps and elastic forces, the effect of the distortion orders and the effect of the inter-ring volumes on the sealing efficiency of the system. In the present work has been proposed to study the effect of the speed and load of the engine on the behavior of the ringpack, and on the blow-by.…”

“…The minimum oil film thickness is assumed to be 5.3 μm. In addition, the liner distortion has been considered as given in previous work [16]. The input data are implemented and solved in © Ricardo RINGPAK solver.…”