Description And Operation

DESCRIPTION 

The Quadrifoglio model has an aerodynamic air dam in the bottom part of the front fascia.

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• Front aerodynamic air dam. (1)

The front aerodynamic air dam distributes the air flow that is routed into the underbody area of the vehicle with the purpose of increasing traction and the aerodynamic load on the front of the vehicle.

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• Front aerodynamic air dam (1).
• Rear extractor (2).

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The front air dam is activated only when the Dynamic or Race driving modes are selected. When other driving modes are selected, the air dam is not activated.

In Dynamic and Race modes, activation of the air dam occurs in the range of speed between 100 km/h (62 mph) and 230 km/h (143 mph). Outside of the speed range, the air dam is always closed.

The Quadrifoglio model has the flat bottom in the lower part of the floor. This creates a cross section air flow channel that converges and then begins to separate in the rear extractor area, thus forming a vacuum. The flat bottom favors the creation of a vacuum effect. In the area of the under-body where there is the minimum cross-section, the maximum value of the speed V? of the air flow and the minimum pressure P2 value, are reached.

The regulated P2 pressure is lower than the pressure of the air flow present in the upper part of the bodies unregulated P1 pressure. This pressure difference generates a downward force that pushes the vehicle towards the ground, consequently increasing traction and road handling. When the vehicle speed exceeds 100 km/h (62 mph), the air dam opens, imposing a variance of the air flow that is heading in the area under the floor of the vehicle. Opening the air dam also implies amplifying the vacuum effect.

The opening of the air dam, beyond accentuating the vacuum effect, primarily allows shifting of the aerodynamic load toward the front bringing about a more responsive character to the vehicle. The shifting towards the front of the aerodynamic load is due to the deflection of the flow around the air dam that, in the open position, behaves like a reversed wing.

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• Development of air flow with air dam closed (1).
• Air dam in the closed position (2).

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• Air flow diverted following opening of the air dam (3).
• Air dam in the closed position (4).
• Zone of the air dam in which the material (carbon) is slightly deformed under the thrust of the actuators/modules (5).

When the air dam is closed, most of the aerodynamic load is shifted towards the rear.

Air Dam Mechanism 

The front air dam is piloted by two modules. One is located in the right part of the deflector Active Aerodynamic Right Module (AARM) and the other on the left side Active Aerodynamic Left Module (AALM).

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• AALM (1)
• AARM (2)
• Transverse support (3)
• Shell protection (4)
• Front aerodynamic air dam made of carbon fiber (5)

Modules 

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The AARM and AALM, integrate an electronic data processing unit with the mechanical part. The electronic unit is equipped with a Controller Area Network (CAN) interface, a microprocessor and position sensor which detect the small movement piston vertical displacement. The mechanical part contains a small electric motor and a reduction gear assembly through which the small electric motor moves an irreversible trapezoidal screw. The AARM receives movement commands from the CDCM.

OPERATION 

During the movement of the air dam, the AALM and AARM (closing or opening), interact continuously through a private CAN line (which only connects the two actuator modules) in order to move the air dam in a synchronized manner.

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In the case where one of the two modules should block, there is an asynchronism created between the two that could damage the air dam. In order to avoid damage, the AARM controls the interruption of the air dam handling. The AARM communicates to the CDCM the asynchronous condition that is created and then attempts, for a few tenths of a second, to resume handling. If the asynchronism still persists, the right actuators module communicates to the CDCM the condition "air dam blocked." In the "air dam blocked" condition, the CDCM communicates to the Instrument Panel Cluster (IPC) the command for switching on the specific damage indicator light with its related message.

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The AALM receives commands exclusively from the AARM through the private CAN data bus that connects them. The only module to exchange data and messages with CDCM is the AARM. The AALM is also connected to the CAN-Chassis data bus network of the vehicle, only for the purpose of software updating.

The right actuator module communicates to the CDCM the following messages:

• Air dam in movement
• Air dam in Target position
• Air dam Movement interrupted for asynchronism.
• Air dam blocked.

Front Air Dam Electrical Diagram 

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AAML = Active Aerodynamic Left Module (AALM)

AAMR = Active Aerodynamic Right Module (AARM)

The AARM and AALM receive battery supplied power by a fuse protected circuit from the front Power Distribution Center (PDC).

• Front PDC (2).
• Supplementary PDC (2).

Actuator Module Pinouts 

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AARM 

PIN	DESCRIPTION
1	Power supply +30 by battery
2	Ground
3	Power supply +15 by battery
4	Power supply +30 by battery
5	CAN-IHS (private)
6	CAN-CH (High) vehicle
7	Power supply +30 by battery
8	Ground
9	Ground (AARM)
10	NA
11	CAN-L (private)
12	CAN-CH (Low)

AALM 

PIN	DESCRIPTION
1	Power supply +30 by battery
2	Ground
3	Power supply +15 by battery
4	Power supply +30 by battery
5	CAN-IHS (private)
6	CAN-CH (High) vehicle
7	Power supply +30 by battery
8	Ground
9	NA
10	Ground (AALM)
11	CAN-L (private)
12	CAN-CH (Low)