In recent years, Turbo-charged GDI technology is more and more widely used, which can meet the high demand of the engine performance and efficiency, but the resulting reliability and NVH issues also need to be paid attention to [1]. Traditional NVH performance improvement is mostly based on the experience design and repeatable test, which lead to longer development period, high cost, and also ineffective results.
NVH performance simulations play more important role in engine vibration and noise prediction along with the development of the simulation technology[2][3]. The force response analysis is usually used to evaluate the NVH performance of the engine structure under the standard excitation. However, dynamic analysis of the crank train, valve train, and piston can be carried out based on the AVL software family, also the vibration and airborne noise of whole engine can be predicted directly at different speed and load [4].
The NVH performance of a turbo-charged GDI engine was studied based on the simulation and experiment in this paper. Firstly the engine NVH targets including the airborne noise, mount vibration and so on are set up, and the targets are broken down into system and component if possible. Secondly, the mechanism dynamics, engine vibration and noise simulations were carried out, and the weaknesses of the original engine design had been found out. Some appropriate structural improvements to the main parts and new NVH performance prediction were done according to the targets of NVH performance. Then experiment results show that simulation method of radiation noise OA level prediction is basically correct, and a series of structural improvement measures are very effective. Some special problems such as the turbocharger noise were also investigated, and some remarkable effects have been achieved.