OVERVIEW
Though performance and drivability were the focal points during
development of the CL, these characteristics were not achieved at the
expense of safety, security and accident avoidance. The CL is
engineered to help drivers avoid collisions and to enhance the safety
of the car's occupants if a collision does occur.
Featured as standard equipment on the CL Type-S, the Acura Vehicle Stability Assist (VSA) system combines the Traction Control System (TCS) and Anti-lock Brake System (ABS), and synchronizes these two elements to assist in enhancing driver control of the vehicle during sudden collision-avoidance maneuvers. Other safety items in the area of avoidance include high intensity discharge (HID) headlights and the center high-mounted stop light.
In the event of a collision, the CL protects its occupants with a computer-designed safety structure with front and rear crumple zones, and side impact intrusion counter-devices that help protect the passenger compartment. To supplement the structural engineering in the body, the CL features standard driver and front passenger Supplemental Restraint System (SRS) dual-threshold air bags with a dual-stage passenger air bag, seatbelt pretensioners with load-limiters, and an advanced side air bag system.
ANTI-LOCK BRAKING SYSTEM (ABS)
The CL's standard 4-wheel ABS enhances steering control during hard
braking. Speed sensors at each wheel send signals to the ABS control
module. When the system detects wheel lockup, it first holds, then
reduces hydraulic pressure to the affected wheel, letting it regain
traction before full braking resumes. The ABS function is also highly
effective on split-friction surfaces, in which one side of the
vehicle has significantly less traction than the other.
While the CL features a three-channel ABS system, the Type-S is fitted with a special four-channel system that works in conjunction with the Vehicle Stability Assist (VSA) system. Both ABS systems operate in three-channel mode during straight-line braking, apportioning braking power to the front wheels independently and the rear wheels in tandem. This enhances the driver's ability to maintain steering control during hard stops on slick road surfaces.
The Type-S model's ABS system automatically switches to a four-channel mode when the system senses high cornering forces. This allows the ABS system to take advantage of weight transfer to the outside of the turn during cornering and apply higher brake pressure to the outer rear wheel for enhanced braking performance.
TRACTION CONTROL SYSTEM (TCS)
The standard equipment Traction Control System (TCS) on the CL coupe
detects wheel slip under acceleration and coordinates use of braking
and ignition retard to regain traction. For the Type-S, TCS function
are incorporated into the VSA system.
In situations where the front drive wheels are on different friction surfaces, such as when one drive wheel is on wet pavement while the other is on dry pavement, the system applies braking action to the wheel that's slipping, allowing the tire with better grip to move the vehicle. In addition, the system also reduces total engine power output to minimize wheelspin.
VEHICLE STABILITY ASSIST (VSA)
First offered in 2000 on the Acura 3.5 RL flagship sedan, the VSA
system is standard equipment on the CL Type-S model. Like the 3.5 RL
system, the CL's system orchestrates the throttle and brakes to
seamlessly integrate TCS, ABS and VSA processes. This innovation is
designed to assist the driver in maintaining control during
cornering, acceleration and sudden collision-avoidance maneuvers by
applying brake force to the right or left front wheel as necessary
and managing the throttle and ignition systems.
By monitoring input from eight vehicle sensors, the VSA system can calculate a predicted range of vehicle response while constantly monitoring the vehicle's actual response and the driver's control inputs. If the actual response is outside the predicted response range, as when cornering forces exceed the tires performance, VSA automatically intervenes with corrective action. In the case of oversteer (which may lead to spin), VSA applies braking to the outside front wheel to counter the unintended yawing tendency. On the other hand, if understeer is detected, VSA applies braking to the inside front wheel and reduces engine power to turn the car back on to the intended course.
Unlike some vehicle stability systems, which can seem intrusive to enthusiast drivers, the CL's VSA is calibrated to add to stability and predictability, without stifling the driving enjoyment of the CL's carefully engineered chassis and double wishbone suspension. An indicator light flashes on the instrument panel while the system is actively enhancing the stability of the vehicle. A cockpit switch is provided to disable the VSA and TCS while leaving the ABS fully functional.
SAFETY STRUCTURE
The CL's passenger "safety cage" was engineered from the earliest
stages of development to meet tough safety regulations. Using super
computers to conduct extensive crash simulations, engineers studied
impact forces on a "virtual car" to supplement actual prototype crash
testing. These tests led to the development of numerous safety
innovations in the design of the CL.
In frontal impacts, straight-section frame box rails with large cross-sections feed impact energy directly into the main frame structure. To meet 2002 federal head-impact safety regulations, the CL's interior has energy absorbing roof-pillar garnishes and roof lining designed to help reduce injury to the occupants. To better deal with offset-impact energy, reinforcements are placed at the roof side rails, floor frame, A-pillars and front and side frame members.
SIDE IMPACT PROTECTION
Extensive reinforcements were made to the CL's structure to help
protect occupants during side impacts. The B-pillar thickness was
increased and stiffened to minimize the possibility of intrusion
during a side impact while a substantial cross member runs
transversely across the floor pan to reinforce the passenger cabin
structure. The doors have special twin side-impact reinforcement
beams as well as impact-absorbing door-lining pads.
DUAL SUPPLEMENTAL RESTRAINT SYSTEM (SRS) AIR BAG
The CL is equipped with a driver's and front passenger's air bag
Supplemental Restraint System (SRS). The driver's air bag is located
in the steering wheel hub, while the passenger's air bag is located
on top of the dash. To ensure maximum reliability, the sensors use
gold-plated electrical connectors. As in all Acura automobiles, the
front passenger's air bag is designed to deploy upward along the
windshield and then back toward the occupant. This provides a large
cushion to help protect the front passenger.
DUAL-THRESHOLD AIR BAGS
To further enhance the operation of the sophisticated SRS system, a
sensor detects whether the driver's and front passenger's seat belts
are fastened. The dual-threshold system uses this information to
determine how much impact force will be required to make the bag
deploy. If either front seat occupant is unbuckled, their respective
air bag will deploy at a lower impact force collision to help protect
the unbelted occupant. Conversely, if the seat occupant's belts are
buckled, their respective air bag will require a stronger impact to
activate.
DUAL-STAGE PASSENGER AIR BAG
To enhance the protection of the front seat passenger during a
variety of frontal impact collisions, varying air bag deployment
speed is used in the CL. This exclusive system, designed specifically
for Acura, uses a dual-stage inflator, and automatically adjusts the
deployment of the front passenger SRS air bag to one of two speeds
based on the severity of the crash and seat belt usage. During a
lower speed collision, the dual-stage inflator system for the
dash-mounted air bag is triggered in sequence, resulting in slower
overall air bag deployment with less initial force. During a higher
speed collision, both inflators operate simultaneously for full
immediate inflation, to correspond with the greater impact force.
FRONT SEATBELT PRETENSIONER WITH LOAD-LIMITER
The CL is equipped with standard driver and front passenger seatbelt
pretensioners. A pyrotechnic device is utilized in the seatbelt
retractor mechanism, which tightens the seatbelt in the event of a
collision. This feature assists in keeping the occupant firmly in the
seat during the initial collision, further enhancing the
effectiveness of the seatbelts. The pretensioner works in conjunction
with a load-limiter, which reduces forces on the occupant during a
frontal collision.
ADVANCED SIDE AIR BAG SYSTEM
The CL features an Acura-exclusive, seat-mounted, advanced side air
bag system for the driver and front seat passenger. The front
passenger seat is equipped with an innovative occupant position
detection system designed to disable side air bag deployment and
prevent injury to a small child (or small adult) if they lean into
the side air bag deployment path. Seven sensors in the passenger
seatback determine the size and position of the occupant to determine
if it is safe to deploy the side air bag. If the child is in the
deployment path of the side air bag, the system will disable the side
air bag from inflating. If the child returns to an upright seating
position, the side airbag will reactivate so it can deploy and help
protect the child in a side impact.
HIGH INTENSITY DISCHARGE (HID) HEADLIGHTS
The CL is equipped with standard reflector-type xenon high intensity
discharge (HID) low beam headlights. Three times as efficient as
conventional halogen lamps, the Acura HID system uses less energy,
with more than double the bulb life. The useful range of illumination
on low beam increases by 39 percent and the increased beam width
eliminates the need for separate fog lights. The CL's high beams use
conventional halogen bulbs and operate in conjunction with HID. An
auto-off feature turns off the headlights 15 seconds after the
driver's door is closed or the doors are locked.
ANTI-THEFT ALARM SYSTEM
The CL is equipped with a standard keyless-remote entry feature,
which locks and unlocks the doors and opens the trunk at the push of
a button. The key fob also operates the standard security system on
the CL. When a break-in is attempted, the horn sounds, the flashers
activate and the starter system is disabled. The system automatically
arms itself after the doors are locked and is disarmed when a door is
unlocked with the keyless-remote fob or with the door key. The alarm
can also be activated by pressing the "hard" button on the
remote-keyless fob.
SECURITY/IMMOBILIZER SYSTEM
The key for the CL is imbedded with an electronic microprocessor unit
that prevents the car from being started, even if a mechanical
duplicate of the proper key shape is used. A transponder built into
the key signals the immobilizer control unit that the key is genuine.
If hot-wiring is attempted, or an unauthorized key is used, the car
simply will not start.