Diesel Engine Performance by Improving Cylinder Bore under Firing Conditions (First Report)

- Performance Prediction of Ideal Cylindrical Bore Accompanied Thermal Expansion by Utilizing CAE -

Abstract

A cylinder block involves bore deformation due to assembling stress of cylinder head and thermal stress. Friction analysis method of a piston skirt was established and the bore deformation effect on engine performance was clarified. Bore distortion analysis revealed the bore profile of constriction at bottom side and expansion toward upper side in the case of normal bore. This distortion is found to be the cause of exacerbation of the trade-off between skirt friction and piston slap. As a result of CAE prediction, ideal cylindrical bore under the highest thermal load condition significantly improved skirt friction, blow-by gas flow and LOC. Simulation results indicated that the change of design parameters for piston and rings lead to additional improvement of engine performance.