A Study Of Cylinder Bore Distortion In V6 Aluminum Alloy Engine Blocks

This study investigates the potential factors which may cause cylinder bore distortion in V6 aluminum engine block with cast-in gray iron liners. In this research, the microstructure, mechanical properties and residual stress of 319 type aluminum alloy engine blocks were analyzed from top to bottom along the interbore regions in the TSR, T7 heat treated and service (dyno) tested conditions. The results suggest that the cooling rate increased significantly along the cylinder in the vicinity of the chill plate at the bottom of the engine block. This caused a significant refinement in the microstructure which increased the hardness and tensile strength at the bottom of the cylinder relative to the top. The increased strength at the bottom of the cylinder prevented the rapid relief of residual stress at elevated temperature, which suggests that the bottom of the cylinder is less susceptible to cylinder distortion.

A Study Of Cylinder Bore Distortion In V6 Aluminum Alloy Engine Blocks

This study investigates the potential factors which may cause cylinder bore distortion in V6 aluminum engine block with cast-in gray iron liners. In this research, the microstructure, mechanical properties and residual stress of 319 type aluminum alloy engine blocks were analyzed from top to bottom along the interbore regions in the TSR, T7 heat treated and service (dyno) tested conditions. The results suggest that the cooling rate increased significantly along the cylinder in the vicinity of the chill plate at the bottom of the engine block. This caused a significant refinement in the microstructure which increased the hardness and tensile strength at the bottom of the cylinder relative to the top. The increased strength at the bottom of the cylinder prevented the rapid relief of residual stress at elevated temperature, which suggests that the bottom of the cylinder is less susceptible to cylinder distortion.

The Effect of Cylinder Bore Distortion on Lube Oil Consumption and Blow-By

It is well known that cylinder bore deformations during engine operation cause a number of problems in piston ring lubrication. Particularly, the deterioration of piston ring and cylinder bore conformability results in a significant increase in lubricating oil consumption. Therefore, measurement and identification of cylinder bore distortion has been an important subject for engine designers. In this study, an analytical lubricating oil consumption model was developed for a diesel engine. Piston stiffness was identified as an important input parameter for the oil consumption model, and the stiffness matrix of the piston was calculated using finite element simulations. In addition, finite element analysis was performed to determine the distorted cylinder block shape in engine running conditions. Pressure curves and loads obtained in actual engine tests were used in the analysis. The Fourier coefficients of a distorted cylinder bore was calculated which characterize the deformed bore orders. Using these Fourier coefficients, several distorted bore shapes were regenerated, including a straight bore and the effect of each order on total lube oil consumption was investigated by means of the oil consumption model.

The Effect of Cylinder Bore Distortion on Lube Oil Consumption and Blow-By

It is well-known that cylinder bore deformations during engine operation cause a number of problems in piston ring lubrication. Particularly, the deterioration of piston ring and cylinder bore conformability results in a significant increase in lubricating oil consumption (LOC). Therefore, measurement and identification of cylinder bore distortion has been an important subject for engine designers. In this study, an analytical lubricating oil consumption model was developed for a diesel engine. Piston stiffness was identified as an important input parameter for the oil consumption model, and the stiffness matrix of the piston was calculated using finite element simulations. In addition, finite element analysis was performed to determine the distorted cylinder block shape in engine running conditions. Pressure curves obtained in actual engine tests were used in the analysis. The Fourier coefficients of a distorted cylinder bore was calculated which characterize the deformed bore orders. Using these Fourier coefficients, several distorted bore shapes were regenerated, including a straight bore and the effect of each order on total lube oil consumption was investigated by means of the oil consumption model.