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Methods to reduce testing time are even more important in recent developments due to high market competition. The Air induction System Noise Response can be checked and improved using frequency response function bench tests. This work presents a case where an induction system is checked and improved to optimum NVH condition using an experimental procedure. Findings, benefits and suggestion to improve method are also discussed. Results are shown for the studied case and vehicle responses are correlated too. The advantages are summarized and conclusions on final vehicle results are discussed.

Noise, Vibration and Harshness has been dramatically improved in recent developments in all vehicle segments. The high competition between manufacturers has forced continuous reductions in overall noise levels of automotive vehicles in every market segment. The attention of NVH engineers now is to reduce noise contribution on each system and their interactions. The interaction between Powertrain and Driveline systems in a rear wheel drive vehicle development has gained even more attention regarding perceived noise. This paper presents the steps taken to identify and characterize a noise peak related to Powertrain and Driveline interaction on a pickup. The referred vehicle presented vibration associated with a rumble noise on the cockpit perceived near top speed. The problem solving process has combined vehicle measurements on road and chassis dyno, and modal tests. Each Measurement step is shown and analysis of each test is discussed.

Aiming to solve pass by noise issues, where the exhaust system is the main source, a bench test was built. It was based on an impedance tube method to measure the transmission loss of exhaust systems of vehicle combustion engines. The test bench reduces time on investigation of acoustic performance of exhausts systems and does not depend on weather conditions. The results were used to compare several proposals under investigation before assembling on the vehicle and also to give a comparable metric for validating numerical simulation modeling and analysis procedure. This paper describes the problems involved in the construction of the evaluation system. Three types of noise source were evaluated, considering pink and white noise.

This paper presents the method applied in the development of an optimized powertrain mounting assembly for a Light Truck Diesel or Pick-up application. The focus of this optimization is to improve the vibration insulation and consequently improve the NVH (Noise and Vibration Harshness) quality of the vehicle. The paper describes the basic mounting design and manufacturing constraint, the simulation modeling basis, inputs required to perform the computational simulation, the experimental work required, also the method used to determine the center of gravity and rotational inertia of the powertrain and a general mounting tuning strategy. The experimental results for an optimized version are also presented and compared to the original one.