Serious Influence of Power-train ratings on Vehicle Noise

Often there is a sudden requirement to improve gradability of a commercial Truck or drivability of a passenger car in view of the competition in the market. It leads to changes such as: higher rated speed of the engine &/or a deeper final drive ratio.

This makes the engine=RPMs rising rapidly to higher levels during vehicle acceleration on the road and then a below struggle with 9 actions starts how to meet Pass By noise of such an upgraded vehicle as well as how to reduce loudness inside the cabin before launch of the vehicle in the market.

Many of these counter-measures add cost to the vehicle as well as their development time along with Tier 1 or 2 suppliers often goes high and a dramatic irony is that the Head of NVH Dept. needs to bear the HEAT !! But that is life !