Acoustic Volume Deflector Structure for Aerodynamic Drag Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The conventional acoustic exhaust volume design under a motor vehicle's floor, with its elongated closed envelope shape, negatively impacts aerodynamic performance and increases fuel consumption due to air turbulence and exposure to obstacles, leading to higher pollutant emissions.
Innovation Solution
A deflector structure with a rounded shape is integrated into the upstream wall of the acoustic volume, deflecting air and guiding it under the volume or above obstacles, minimizing air resistance and protecting the exhaust line from collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the acoustic volume is arranged longitudinally in the hollow part of the longitudinal central tunnel under the vehicle floor, then it can effectively attenuate exhaust noise, but its air resistance is increased due to turbulence of air arriving under the vehicle
Solution Approach 1:
The deflecting structure incorporates a rounded lower part with a radius of curvature of at least 20 mm that is convex toward the incoming air flow. This curved geometry smoothly redirects air flow around the acoustic volume, reducing turbulence and minimizing energy loss while maintaining the acoustic volume's noise attenuation function.
2Object-generated harmful factors
If the acoustic volume is arranged longitudinally under the floor, then it can attenuate exhaust noise, but it is exposed to obstacles passing under the vehicle which can deteriorate the acoustic volume and damage the exhaust line
Solution Approach 1:
The deflecting structure is positioned at the front of the acoustic volume to preemptively redirect air flow and moving obstacles away from the acoustic volume and exhaust line. This preliminary deflection prevents direct impact and potential damage before the obstacles can reach the vulnerable components.
Solution Approach 2:
The rounded lower part of the deflecting structure with its convex curved surface smoothly guides moving obstacles over the acoustic volume rather than allowing direct contact, thereby protecting the exhaust line and acoustic volume from impact damage while maintaining noise attenuation performance.
3Object-generated harmful factors
If the acoustic volume has an elongated closed envelope shape, then it can effectively attenuate noise, but it has a negative impact on the vehicle's penetration into the air and increases fuel consumption
Solution Approach 1:
The rounded deflecting structure with its curved lower surface optimizes the aerodynamic profile of the acoustic volume assembly, enabling air flow to follow the contours more smoothly and reducing wake turbulence. This improves aerodynamic penetration and reduces the energy required to move the vehicle, thereby lowering fuel consumption while preserving noise attenuation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enhances aerodynamic performance, reduces fuel consumption, and minimizes pollutant emissions by improving air penetration and obstacle management without altering the vehicle's ground clearance, achieving a significant gain in aerodynamic coefficient and reducing CO2 emissions.
Implementation Method 1
said part being capable of deflecting the air arriving at the acoustic volume and of guiding it under the acoustic volume
Implementation Method 2
avoiding obstacles by deflecting moving obstacles or by guiding the exhaust line above a fixed obstacle
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
Device, suitable for placement under the floor of a motor vehicle, comprising an acoustic volume (1) attenuating the noise of the engine exhaust gases which has an elongated envelope (10) closed at its upstream end by an upstream wall (3), and comprising a deflecting structure (2), characterized in that said deflecting structure is a part (2) located at least partly on the external face of said upstream wall of the acoustic volume, comprising at least one lower rounded deflecting part (20) extending on the one hand vertically at least over the lower part (300) of the external surface of said upstream wall (3) and on the other hand transversely to the longitudinal direction of the envelope of the acoustic volume, and with convexity turned in the opposite direction to said upstream wall.