Page 42 - ATZ WORLDWIDE

DEVELOPMENT AERODYNAMICS

FIGURE 2 Mapping of the coefficient of pressure on a vehicle showing ram air pressure, skin friction and wake (© Creo Dynamics)

– identifying areas for improvement underbody airflow to achieve drag ing parameters were changed to achieve
– designing, meshing and running reduction is substantial. an optimal drag reduction, resulting in
Computational Fluid Dynamics (CFD) The active front deflector, most effec- an 11-count benefit. Testing included up/
analysis to determine potential benefits tive on higher ride vehicles due to mini- down and fore/aft variations, with spe-
– using physical wind tunnel testing mal underbody shielding, modifies air- cific trends discovered through testing
for drag reduction validation and flow by bypassing the complex under- that allows Magna to provide a strong,
influencing factors body and tyre ram air pressure. The up-front proposal. Additionally, early
– correlating CFD to physical testing location, shape, deployment distance involvement in vehicle styling and sys-
– creating the system framework and deployment type of the front deflec- tem design will maximise benefits.
through design and engineering tor varies by each vehicle due to ride As expected with an active aerodynamic
– identifying opportunities for height, packaging, styling and under- system, actuation is paramount to ensure
inte gration and optimisation. body complexities. This drives unique an effective system. In coordination with
system travel types, including rotational, Magna’s closures and mirrors groups,
linear and compound. In addition to Magna Exteriors has developed a LIN-
INNOVATIONS IN ACTIVE
AERODYNAMICS providing drag reduction benefits of based, sealed, high-speed, high-torque
12 to 18 counts, the active front deflector actuator with an internal clutch to meet
As the first broadly used solution for works in conjunction with the active the demands of our new aero systems.
drag reduction, AGS have seen consider- grille shutter and thermal management
able growth globally and are considered system to optimise drag and cooling, CONSIDERATIONS FOR
fairly common in today’s market. Magna respectively. APPLICATION
has multiple patents for active aerody- The Active Underbody Panel (AUP) is
namics and has one of its patents in pro- designed to work similarly to the active As the demand for improved aerodynam-
duction, FIGURE 3. front deflector but is effective on low-rid- ics increases, it is necessary for automak-
In the near future, Magna will sup- ing vehicles. The system deploys an ers to consider the application of active
ply the automotive industry multiple underbody panel to reduce drag and systems at the start. By analysing the
aero technologies, with a strong focus wake. Investigations show drag reduc- vehicle with active aero early on (during
on modifying underbody airflow tion values of 10 to 15 counts. FIGURE 5 clay design stage), studios can under-
through innovative active front deflec- shows results from a production vehicle stand the impact of aero on styling.
tors and active underbody panels, in a full-scale moving ground plane Additionally, multiple aero systems can
FIGURE 4. Through CFD and wind tun- wind tunnel. Using a detailed test plan, be analysed together to ensure they work
nel analysis, the company has deter- the existing underbody panels were in harmony and will provide the greatest
mined that the value of modifying modified for the wind tunnel. The test- benefit.

FIGURE 3 Active grille shutter multi-part
modular frame patent (© Magna)
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