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Technology with a Purpose

Cadillac touts user-friendly advanced technology systems as key to new STS appeal.

The STS wears a conservative version of Cadillac’s Art and Science design theme.
After years of playing second fiddle to the competition in the upper luxury market, Cadillac is aiming for tier one status with its all-new 2005 STS.

Most importantly, the new flagship sedan from General Motors’ luxury division switches from front-wheel-drive to rear-wheel or allwheel- drive in order to compete effectively in a class dominated by rear-driven cars.

The STS adopts the Sigma architecture that has already proven successful in the Cadillac CTS sedan and SRX sport utility models. At 196 in. long, 72.6 in. wide and 57.6 in. high, with a 116.4 in. wheelbase, the STS is the largest of the Sigma family.

When the Lansing-built car reaches showrooms in the last quarter of 2004, buyers will have a choice of 320 hp Northstar 4.6L V-8 (in rear or all-wheel-drive configuration) or 255 hp 3.6L V-6 powertrain in rear drive only. Both engines feature variable valve timing (VVT) and use GM’s electronically controlled fivespeed automatic transmissions.

The Hydra-Matic 5L50-E is mated with the V-8, and the Hydra-Matic 5L40-E with the V- 6. Both transmissions incorporate driver shift control (DSC) and performance algorithm liftfoot (PAL) technologies.

The interior is all Cadillac in look and feel but filled with plenty of high tech or “purposeful technology,” unlike some luxury cars that suffer from over-complex control ergonomics.
Driver shift control enables the driver to switch from automatic to a clutchless five-speed high-performance manual transmission. Once the driver moves the gearshift lever into DSC mode, it operates with a fore and aft tap motion. Performance algorithm liftfoot inhibits upshifts while maintaining engine braking following continuous aggressive driving. The transmission control module (TCM) monitors driver behavior to determine whether or not to enable this feature.

For example, if the system detects a drop in vehicle speed prior to entering a turn or a lane change, up to two downshifts can occur to provide the driver with maximum engine response. The sophisticated suspension includes a two-mode magnetic ride (MR) control system, four-channel StabiliTrak, and an optional high-precision ZF steering gear.

The SLA front suspension uses aluminum for the upper and lower control arms, knuckles, and brake calipers, reducing overall mass and improving wheel control. Front shocks on base models are monotube dampers from ZF Sachs, while up-level versions offer the Delphideveloped MR system.

For crisper steering response, ZF’s Servotronic II steering gear is available. This speed-sensitive steering gear has an 18.2:1 variable ratio, speed-sensitive variable assist, and a turning radius as little as 11.5 meters. “Now we have legitimate hardware to go nose to nose with the competition,” says vehicle line executive Jim Taylor, who lists the BMW 5- Series, 7-Series, Lexus GS300/LS430, Mercedes E-Class and Audi A6 among STS rivals. Compared to the Japanese competitors, the STS will stress its performance edge, says Taylor. And versus the German rivals, the Cadillac’s advantage will be its “purposeful technology,” a reference to the well-publicized problems experienced by BMW and Mercedes with over-complex control ergonomics.

Along with its impressive array of powertrain and chassis hardware, the STS showcases a host of advanced convenience systems.

The list includes keyless access with push button start, smart remote start, intellibeam and the Bose studio surround sound system, claimed to be the audio company’s most sophisticated yet.

A crucial enabler for the STS’s technology systems is an electrical backbone, known as a LAN (local area network) serial data system. This GM-developed electrical architecture comprises a high- and low-speed data network that connects system modules and ensures that information is properly communicated and shared between them.

In all, the STS is equipped with up to 27 modules, located throughout the vehicle, depending upon options selected. Each module sends and receives information sent via the LAN. First introduced on the Cadillac XLR roadster last year, the keyless access/push button start system allows users to enter the STS and operate a push-button ignition with a personalized, keyless fob. With the key fob in a pocket or purse, the driver can approach a locked vehicle, pull the door handle and open the door.

The same concept applies when opening the trunk. As a result, the need to pull keys out — or even the fob — to activate the door and trunk functions has been eliminated. The system uses passive and active antennas to detect the vehicle fob and its proximity to the vehicle. Once inside the vehicle, the fob-carrying driver’s presence is detected by another set of antennas. The car’s security system checks the fob’s code and allows the driver to start the engine with a short push of an instrument panel button.

 The STS’s Sigma architecture, shared with the SRX and CTS sedan, is adaptable to either rear drive or all wheel drive and comes with a choice of 320 hp Northstar 4.6L V-8 or 255 hp 3.6L V-6.
Aside from requiring the fob to be inside the vehicle, the system also calls for the brake pedal to be depressed before the engine will start, as a means of preventing a child from operating the car.

A related system to keyless access is the STS’s “smart” remote start. Using the fob, this operates from as far as 200 feet and not only starts the vehicle, but also automatically adjusts a variety of personalization settings in the process.

Though other vehicles now have remote start, the STS’s smart system allows the car to begin to prepare the interior climate to previously chosen temperature settings before the driver enters. As well as adjusting cabin temperature, the system starts the seat heating or ventilation operation (depending on exterior temperature readings) and also activates front and rear window defroster if climate conditions require it.

The STS joins an exclusive band of luxury vehicles in offering adaptive cruise control (ACC). Similar to the system pioneered on the XLR, the STS’s ACC uses a radar sensor mounted behind the grille’s wreath and crest badge. The sensor detects objects in its path and if the lane ahead is clear, the system will maintain the set speed. When slower traffic is detected, the system will automatically adjust to a safe distance (selected by the driver) by using throttle control and limited braking. The ACC system used on the STS incorporates two new features: grade braking and audible alert. With grade braking, the transmission automatically downshifts to maintain selected vehicle speed and distance, preventing overheating of brakes.

The audible alert function operates when ACC is active, notifying the driver when he or she is too close to a preceding vehicle. All adaptive cruise displays are shown through the fourcolor, reconfigurable head-up display (HUD). As well as ACC information, the HUD incorporates an infotainment data display, tap gear display and shift indicator display along with turn-by-turn directional navigation and audio band, frequency, and pre-set information — all based on driver preference. It is also configurable to five languages: English, French, Spanish, German and Italian.

Though high-intensity discharge (HID) xenon lighting is not unusual in the luxury class, the STS’s large 70-millimeter projectors stacked vertically in each headlamp housing provide excellent light spread and are equipped with an “intellibeam” system. This automatically switches headlamps from high- to low-beam and back again when oncoming headlamps or forward lighting elements are sensed. The system uses a metaloxide semiconductor (CMOS) light sensor located on the back of the rearview mirror. The CMOS contains a miniature camera, light sensors and microprocessor that sense oncoming light. When it detects an approaching vehicle’s headlights or preceding vehicle’s taillamps, the system turns off the high beams gradually before it distracts other drivers. The system also detects and effectively ignores ambient light coming from streetlights, sign reflections, buildings and other sources. In situations where light from an approaching vehicle is more immediate, such as when cresting a hill, the system reacts instantaneously, automatically switching to low-beam.

On the subject of lighting, the STS’s LED tail lamps are designed with indirect optics, an industry-first application, and incorporate 30 sources of illumination per unit. The use of indirect optics eliminates “pinpoints” of light normally associated with LEDs and enables an upscale, refined appearance when illuminated. On the STS, each tail lamp has two vertical arrays consisting of 15 LEDs, and each LED has 20 optical facets. This configuration enables precise illumination tuning and the design flexibility needed to meet domestic or export requirements.

The LED CHMSL on the STS is only 12-mm thick and consists of 78 points of illumination. A clever lens design incorporates the use of pillow optics, which replaces the “pinpoint”appearance normally associated with LEDs with a smooth, refined output of light.

Inside the STS, Cadillac claims to be one of the first in the industry to offer a surround sound audio system. Developed by Bose, the optional 300-watt system has no less than 15 speakers mounted throughout the cabin, including four 50-millimeter mid-high range speakers integrated into the driver and front passenger seats.

The system can deliver true 5.1 channel surround sound and also produces ‘rich’ twochannel audio due to Bose’s proprietary processing technology.

An optional factory-installed, in-dash sixdisc DVD changer supports a variety of media formats, including 5.1 channel surround sound. The system also incorporates dual media slots — one for entertainment and the other for DVD-based navigation — reducing the time taken changing media and ensuring fulltime navigation capability.

Media formats supported by the DVD system include DVD audio, DVD video, CD audio and MP3. Media types supported are CD/DVD ROM and CD/DVD-R. DVD video can only be activated when the vehicle is in “park.” When equipped with the up-level infotainment package, the STS has a large 8 in. diagonal high-resolution full VGA infotainment display head with full touch screen and fourposition tilt function.

The display head — which is positioned high in the center stack and is flush with the surface of the instrument panel — has an 800- by-480 pixel resolution and a viewable area 20 percent larger than most current offerings. The four position tilt-screen incorporates memory recall and offers 5-, 10- and 15-degrees of tilt, enabling the driver to select the best viewing angle based on environmental conditions. The DVD-based navigation system available on the STS conducts route calculation 30 percent faster than current systems, displays freeway exit information (gas, restaurants, services) via expandable icons, and covers all roads and streets in the U.S. and Canada (nearly seven million miles) on a single map DVD. The system allows route planning to items stored in memory via voice commands and/or voice tags.

The STS has cellular telephone accommodation for the factory-installed OnStar system and portable Bluetooth capable phones through the up-level infotainment system, which enable hands-free operation, screen and voice dialing of phone numbers.

A final element in the STS’s electronic arsenal is its voice recognition system, which Cadillac claims to have been significantly enhanced over previous applications.

The system offers continuous speech capability, multiple language support (English, French, Spanish, German and Italian) and more than 150 voice commands, including those for the infotainment and climate control systems. Even the raising and lowering of the power windows can be controlled by voice. Though the STS has as many, if not more, advanced electronic systems as do rival luxury sedans on the market, Cadillac is counting that the car’s logical, simple approach to the management of these systems will become part of its showroom appeal.

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