[ Fourth generation Prius Aerodynamics ] photo & text by tw

(Original text : August 20, 2016 / English translation : August 23, 2016)



Fence was somewhat block the view, but was able to shoot the lower body of the fourth generation Prius.



Front-under, completely does not seem to become the flat.
But it might be a hi level of more than the existing passenger car.
However, I would like you to aim for perfection to the manufacturer.

Then, since the recessed shape of the lower side of the lamp, which disturbs the air flow towards the body side.(Recessed)
Under the CG is, my suggested solutions.



As shown by the light blue of the frame, it does not inhibit the airflow be covered in the clear panel.
This Toyota is, or was dismissed from the design of the product in question?
Than the Earth resources and environmental issues, or those of good looks is important?




Position of front brake pads, front side. It diagonally upper side.
This position is often seen in the passenger car.

The position of the Caliper is, it is disadvantageous in the elements of the body of the weight distribution.
The center of gravity is higher. The body of the moment of inertia is increased.
But disadvantageous to the cooling of the pad.
However, Toyota that is likely the reasons this position, but the following items.

First of all, there is a possibility that the steering rod is in the rear side of the axle.
Since the caliper is there is a range, but in order to avoid interference with the steering rod.

The arms and rods are longer it is excellent in the performance of the suspension for a variety of reasons.
When the arm is long, the tread variation during the stroke is reduced.
For the relief of the power required for the power assist steering, I want to close the arm to the kingpin.
Upon they set the caster angle of the ideal, if it has a lower arm in front of the axle?
If it can convince the reason for the pad diagonally upward.




And the handle of the door, the surface in contact with the front and rear door.



If rear teardrop of the handle of the door, there is a case in which air resistance is reduced.
However, when the airflow like the image shown is disturbed above are not very effective.
And, if want to tear drop, necessary contrivance that does not interfere when open the rear door.




Brake caliper of the rear wheels, as is common in other passenger car, in the back side, it is located on the diagonal.
This is also, in terms of body weight distribution, a bad position because the height of the center of gravity and moment of inertia is increased.
However it would be advantageous for the cooling of the caliper and pad.
Unlike racing car, in the case of passenger car suspension arm is heavy and thick.
If the toe arm is at the front, it can be satisfied with the reasons for the caliper on the rear side.




In the theory of fluid dynamics, reducing the resistance to the body rear end to cut spoiler.
4 generation Prius are the back and the top and sides to cut spoiler.
However, the lower side surface not performed. However, in their side bottom it has not been performed is cut spoiler. The reason is possibly..,




Since the rear wheels to rotate is exposed, it is not cleanly along the body air in the lower side surface.
Therefore low effect of cut spoiler to, perhaps did not thoroughly cut spoiler to the four corners with an emphasis on looks.

If, as Honda's first-insite, I think that the rear wheel can be cowling.
In the Honda development member of the comments at the time, the aerodynamic effect of wheel cowling after If you do not narrow the width of the rear end was the opinion that low.
narrow the rear tread, the oversteer. And running stability, space of the trunk room is the disadvantage.
Oversteer can be corrected in the setting, but the passenger car would like to increase the luggage compartment space I can understand.




Perhaps, the lower arm is inhibition of the vehicle body underside airflow.
Cut spoiler would be better than not.

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