Aerodynamics

The highly efficient aerodynamic drag figure of 0.29 for the 2005 Acura RL pays dividends in the form of lower wind noise, improved fuel economy, increased performance, and enhanced stability on the highway. An air dam reduces front lift force. An engine undercover and floor undercovers further smooth airflow, as do muffler covers and a rear diffuser, which help rear differential's cooling and result in rear lift force reduction.

Active Front Lighting System

The RL features the first Active Front Lighting System (AFS) ever on an Acura. It also has Xenon High-Intensity Discharge (HID) headlights, 55-watt fog lihts, and daytime running lights. All are standard equipment.

In the Active Front Lighting System, the left low-beam unit can swivel left, and the right low beam can swivel right, to improve illumination while cornering, or to illuminate around the corner of an intersection. This allows the driver advance warning if a pedestrian, object or animal is in the way. Each light can swivel up to 20 degrees outboard, with the amount determined based on the vehicle speed and steering input.

The system uses the following components:

• Steering angle sensor
• Vehicle speed sensor
• Reverse switch (cancels AFS when car is backing up)
• Control switch (turns off AFS at driver's discretion)
• Instrument panel warning light (illuminates when AFS is turned off)
• Control unit swivels the headlight low beam projector unit via a gearbox and step motor

AFS swivels either the left or right headlight (not both together) when the following conditions are met:

• Steering angle is over 12 degrees
• Vehicle speed is 5 mph or higher (left-hand turns only)
• Right-hand headlight will swivel even if vehicle is stopped
• Swivel cancels when speed drops to 3 mph (left-hand turns only)

Xenon High-Intensity Discharge (HID) Headlights

Traditional headlight bulbs illuminate a tungsten filament inside a sealed bulb containing halogen gas. Xenon HID low-beam bulbs, however, use a high voltage current that passes between two electrodes to create a plasma arc. This accounts for their brightness and "daylight-like" illumination.

LED Lighting

The RL also features advanced Light Emitting Diode (LED) lighting systems. These include LED mirror integrated directional signals, each of which features bright LEDs to alert motorists who are alongside when the RL driver is planning to change lanes or make a turn.

Each taillight/brake light assembly has an array of 28 LEDs. The taillights use 14 LEDs, arranged as the perimeter of a circle, and the brake lights use an additional 14 LEDs. When the brakes are applied, all 28 LEDs light up, illuminating the entire area.

The center high-mounted stop lamp (CHMSL) also uses LEDs. The projected service life of the RL LEDs is 2,000 hours.

Daytime Running Lights

The RL features Daytime Running Lights (DRL) for the first time in an Acura in the U.S.

5 MPH Bumpers

To minimize repair costs in minor, low-speed collisions, the RL has 5-mph bumpers front and rear.

NVH Countermeasures

The elimination of undesirable noise, vibration and harshness (NVH) in the 2005 Acura RL was of primary concern to development engineers. Virtually everything that could be the source of these traits was scientifically reviewed and modified during the planning and prototype phases.

Acura wanted to provide RL clients with 300 hp, all-wheel drive and large-diameter high-performance tires for advanced handling characteristics. At the same time, they wanted the car to remain refined and nearly silent for highway cruising and have a stirring high-performance engine sound during acceleration. These attributes, along with low NVH and light overall vehicle weight, were achieved through the application of innovative technology.

The new RL is dramatically quieter than the 2004 3.5 RL in terms of high frequency and middle-frequency noise attenuation. Acura's internal testing also shows that it is also significantly better than the Audi A6 and Mercedes-Benz E320. Road noise attenuation is also significantly improved over both smooth and rough roads.

As part of the mission to control weight in the new RL, Acura used lightweight materials wherever possible in the sound-absorbing package, including lightweight sound insulators instead of traditional heavier materials. In addition, the RL represents Acura's first use of an Active Noise Cancellation^TM system (ANC). See Interior section for more information.

Main RL NVH countermeasures:

Drivetrain

• Engine mounting system including a hydraulic lower transmission mount
• Variable volume mufflers
• Hood insulator
• Engine cover and undercover

Body

• Acoustic roof lining
• Acoustic front and rear inner fender insulator with high-frequency damping materials

Flooring

• Lightweight floor insulator
• Floor undercover

Subframes

• Floating front and rear subframes with four mounting points

Interior

• ANC system for noise control (see Interior section for more information)
• Lightweight instrument panel damping materials
• Thinsulate insulation in selected areas

Trunk

• Acoustic design with side, front and lid linings

Power Windows

The side power windows on the RL are made of glass that is 5 mm thick to reduce cabin noise. Each window features an auto-open and auto-close function as well as an anti-pinch safety feature and key-off operation.

Flush Glass

The 2005 Acura RL is the first car in the world to have totally flush side glass where it meets the B-pillars. Normally, a gap of about 5 mm exists between side glass and the B-pillar. But on the '05 RL, the window guide is on the glass instead of the window frame, which allowed the gap to be eliminated. This means there is one continuous uninterrupted plane running along the front side window, across the B-pillar and all the way to the trailing edge of the rear side window. The benefit is a further reduction in wind noise and an even cleaner, high quality appearance.

Exterior Mirrors

To reduce wind rush and turbulence, exterior mirror housings need to be small and aerodynamic, without unnecessarily reducing the mirror area. On the RL, the power mirror element is precisely sized to fit inside a compact housing that reduces these unwanted characteristics.

The airflow between the mirror housing and the side window glass is likewise crucial for reducing turbulence and noise. Engineers designed this gap as an expanding V-shape, with the gap narrower at the front and wider at the rear. This helps the airflow decelerate as it flows across the glass, instead of accelerating as it would if the V-angle were to decrease. The result is smoother airflow and less mid- and high-frequency noise.

Exterior Paint

The exterior paint on the 2005 Acura RL uses an environmentally conscious water-based process. The painting procedure begins with an electrodeposition (ED) primer, which is electrically charged in the paint bath. After the ED primer is applied, it is cured at high temperature to improve corrosive durability.

Next comes a primer-surfacer (PS) that is hand sanded to ensure a smooth surface for better appearance. After a waterborne color basecoat (BC) is applied, a pair of clear coats provide depth while helping to protect the base coat from air pollution, acid rain and fog.

Nine different exterior colors are available, including four metallic colors and five pearl colors. These are selectively available with three different interior colors. The chart below shows the available exterior/interior color combinations (see Interior section for more information).

Select Page Aerodynamics Interior Safety Page: 1 of 3