GM Has New Patents Approved for Active Side Skirts, Spoilers and Downforce Generating Ducts


GM Has New Patents Approved for Active Side Skirts, Spoilers and Downforce Generating Ducts

We’ve been hearing the whispers and rumors about Adaptive Aerodynamics for some time now and again I like to credit Car and Driver’s Don Sherman for first mentioning the possibility of active aero on future Corvettes back in August 2016. Just under a year later in March 2017, GM filed a patent application detailing a system that monitors and adjusts vehicle ride-height for control of vehicle aerodynamics.

That first patent application for Adaptive Aerodynamics was described as “vehicle ride-height determination for control of vehicle aerodynamics”. The application details an adjustable spoiler, air dam, front splitter, rear diffuser and shutter. These aerodynamic parts would be controlled by a computer that could make minute adjustments to the various angles to either increase downforce or trim aerodynamics for speed based on the ride height of the Corvette.

Now we are learning about three new patents recently awarded to GM that detail additional adaptive aero technologies that could be headed for future GM vehicles including the C8 Mid-Engine Corvette: Active Side-Skirts, Active Spoilers, and Downforce Generating Ducts.

The three individual patents detail each of the systems and how they work, and all three technologies show the drawings integrated into the C7 Corvette body style.

Active Side Skirts

The patent publication explains that vehicle side skirts are an aerodynamic device typically fitted to a vehicle body side between the front and rear wheels. The purpose is to help streamline ambient airflow around the rear wheels to reduce drag. According to the summary in the patent, the larger the area of the side skirts, the lower aerodynamic drag on the vehicle.

The Active Side Skirt system utilizes sensors to detect the rotating speed of the wheel as well as the speed of the vehicle relative to the road surface, and a controller is programmed to send commands to actuators that can extend and retract the side skirts “toward and away from the road surface”.

GM Patent Illustration for Active Side Skirts

GM Patent Illustration for Active Side Skirts

GM Patent Illustration for Active Side Skirts

Click here to view the GM Patent for Active Side-Skirts for a Motor Vehicle.

Active Spoilers

Like the side skirts, spoilers are used to “spoil” unfavorable air movement across the body of a vehicle in motion, usually described as turbulence or drag. Adding a spoiler at the rear of the vehicle helps to delay airflow separation from the body. As we have learned recently from the two different styles of the spoilers on the 2019 Corvette ZR1, a spoiler mounted as a certain height and angle can either help to reduce lift and create downforce like the ZR1’s high wing, or it can be used to streamline the airflow to reduce drag as is the function of the ZR1’s low wing.

Of course, nobody wants to carry around two different spoilers. So the Active Spoiler system detailed in the Patent publication solves that problem.

Stanchions are used to support the spoiler body relative to the car. Connected to a gear and motor system, they can be configured to vary the height of the spoiler. A second process is configured to selectively pivot the body of the spoiler to change the angle and thereby adjust the aerodynamic downforce generated by the spoiler.

Like the active side skirts, the active spoiler can include sensors that communicate a variety of information for controlling the active spoiler. Sensors look at the rotating speed of the rear wheels as well as detecting the velocity of ambient airflow relative to the vehicle. Other sensors look at the steering wheel angle as well as detecting the yaw rate. All these sensors feed information to the controller which then adjusts the height and angle of the spoiler.

GM Patent Illustration for Active Spolier

GM Patent Illustration for Active Spolier

GM Patent Illustration for Active Spolier

Click here to view the GM Patent for Active Spoilers for a Motor Vehicle.

Downforce Generating Ducts

This next patent is pretty straightforward for what is described as downforce generating ducts. We all know that ducts are used on the Corvette to move air from one part of the car to another. The C7 Corvettes featured ducts on the rear quarter panels that are used for cooling the transmission and differential fluids. On a mid-engine platform, cooling is even more important as you need forward-facing ducts to capture the air and then route to the various areas that need additional cooling.

In this patent publication, GM describes the ducts as a fully-enclosed structure, and it contains a first or entry port positioned to receive the ambient airflow and a second or exit port to exhaust the airflow from the duct. The first and second ports together with the fully-enclosed structured are configured to generate an aerodynamic downforce on the vehicle body when it’s in motion.

GM also notes that the ducts can be found both top and bottom of the car and that they can include a venturi to accelerate the portion of the oncoming ambient airflow.

GM Patent Illustration for Downforce Generating Ducts

GM Patent Illustration for Downforce Generating Ducts

Click here to view the GM Patent for Downforce Generating Ducts for a Vehicle.


Patent Application Details Adaptive Aerodynamics Plans for C7 Corvette
New GM Patent Reveals a High Compression Engine with Multi-Stage Boosting
General Motors Continues Fight for Corvette Trademark in Australia




Comments are closed.