Abstract
For improving thermal efficiency of K-car engine under usual operating conditions, the authors explored the optimized engine parameters applying quality engineering tool for 0-D engine cycle simulation model. In this simulation study, the potential for improving thermal efficiency was clarified by exploring various engine geometrical parameters such as bore and stroke, compression ratio, connecting rod length and intake valve timing, etc. regardless of the engine displacement standard for K-cars. The results indicated that super high expansion ratio engine which has the piston swept volume beyond 660 cm3 significantly improved the thermal efficiency for K-car engines.