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The highlights of turbocharging technology with the gain and loss on NVH characteristics were addressed. We did the statistics study of engine types of SUVs and sedans to provide a useful insight of North America market. The design viewpoints and the configuration changes from naturally aspirated (NA) changing to turbocharged (TC) engine were discussed. We investigated the NVH characteristics between NA and TC engine in a more general sense. The discussion included the NVH impacts and noise abatement. We illustrated a case study on a gasoline engine with NA and TC versions to highlight the turbocharging effects on NVH behavior.

We assessed the feasibility of weight reduction concerning noise and vibration characteristics for engine components. Three alternatives were plastic intake manifold, stamped steel oil pan, and no balance shaft. The assessment indices were engine noise level, engine mount bracket vibration, and engine block vibration. Reducing the reciprocating mass and applying design alternatives made the removal of balance shaft feasible. The lightweight plastic intake manifold was beneficial to the engine vibration with a little improvement to the engine noise. The stamped steel oil pan, with optimal structural ribs design and EMS calibration, offered all the benefits of weight, vibration, and noise improvements.

This paper focuses on the diagnostic methodology and troubleshooting process for the coast down noise annoyance for two types of scooters. Both the subjective noise assessment and objective evaluation of the gearbox near field noise and gearbox case vibration were performed in this work. The objective evaluation adopted time analysis, spectrum analysis, order analysis and binaural analysis to identify the acoustic characteristics of the noise annoyance. In addition, the excellent correlation between gearbox case vibration and abnormal coast down noise was confirmed. The diagnostic results show that the noise annoyance is resulted from the improper assembly clearance tolerance between specific parts for Type A scooter, and from the improper clearance between specific parts for Type B scooter.

The study employed the rig test method for the intake/exhaust noise investigation by using shaker. This article describes two case studies including 1.2 liter minivan and a 250 c.c. motorcycle. For the minivan case, it was verified that along with the reduction of 5∼8 dB(A) of intake noise the interior noise was also improved using the rig test optimization result. For the motorcycle case, It was found that there was very good correlation of the exhaust noise measured among the engine dynamometer, road test and rig test after the temperature effect was compensated. Hence, the study chose the rig test as a development tool to get prompt NVH evaluation results on the different exhaust pipe lengths and keep the development time schedule. From the results, it is concluded that the simple and cheap rig test evaluation technique is vital and a very effective tool to achieve the vehicle NVH development goal.

This paper highlighted the up-to-date major efforts and progress on chassis development for a shared platform project. The project history was described briefly. We determined the proper vehicle and chassis specifications according to the intensive benchmarking from literature review, statistics study of the available automotive database, and benchmarking tests. An introduction of our in-house designed kinematics and compliance (K&C) rig and the discussion of the associated K&C test results were offered. We addressed a steady-state constant radius driving behavior simulation as an illustration of our work on virtual validation. Finally the results of dynamic handling validation tests of prototype vehicle were discussed.