Networked Systems = Safety and Comfort; New Passat Relies on Continental Brake and Transmission Technologies

AUBURN HILLS, Mich., June 1 -- Closely networked systems and components developed by Continental Automotive Systems help advance Volkswagen's new Passat to the front of the class. Continental helped develop and produce cutting edge technologies to optimize braking, shifting, ride and performance features of the new model.

Double-clutch transmission: tough conditions for control functions

The double-clutch transmission in the new Passat sets a benchmark in drivetrain technology, combining the comfort and convenience of an automatic with the sporting performance and fuel economy of a manual gearbox. The key advantage of this new transmission is its use of two clutches. As one clutch disengages for an up-shift, the second one engages immediately, bringing the next gear into action. There is no acceleration gap like a conventional manual gearbox. The power losses associated with a conventional automatic are also a thing of the past. Yet the new unit is just as convenient as an automatic transmission -- there is no clutch pedal to operate.

The driver just accelerates and brakes -- everything else is handled by a Continental Temic mechatronic control unit with smart electronics and sensors integrated into the transmission housing. In an environment that can reach temperatures of 293 degrees the nerve center of the transmission synchronizes operation of the two clutches with the gearshifts. It also shares information with the engine management unit that automatically throttles the fuel supply at just the right moment to avoid any jolts or unpleasant noise -- all in the space of milliseconds. The driver can leave gear shifting to the electronics or shift manually by tapping the selector paddle. It is as convenient as an automatic but offers all the driving pleasure and fuel economy of a manual gearbox.

CAN Gateway: keeping the data highway flowing

In the new Passat, the switches, sensors and motors for electronic functions are networked. A CAN (Controller Area Network) bus interlinks all these components on a common cable system which one could imagine as a bus route from A to A with stops at B, C, D, E and F. This configuration saves wiring and reduces weight at the same time as enhancing reliability. The challenge is to make sure that the individual control commands (window down, change radio station, adjust seat or door mirror) all reach the correct destination quickly, reliably and without interfering with other equipment.

Like all other Volkswagen vehicles, the new Passat uses a CAN gateway from Continental Temic for this purpose. This control unit recognizes which signals are to be transmitted to each destination within the vehicle and can also identify their priority. For example, if the commands "close sliding roof" and "switch on brake light" meet on the data highway, the second signal is given absolute priority because it is safety-relevant. Recognizing the priorities at once, the CAN gateway makes sure that the signal from the brake light switch on the brake booster reaches the brake lights as fast as possible.

Brake system: comfort, performance and quality

For the first time on a volume production model, a "no-contact" brake light switch is located on the Passat master cylinder. It has the advantage of better protection against damage and no mechanical wear compared to a conventional mechanical switch.

Initiating emergency braking in the Passat takes very little effort. The brake booster developed and supplied by Continental Teves has a two-stage design. If the driver presses the brake pedal quickly, indicating a possible emergency situation, the second stage of the brake booster cuts in, enabling even inexperienced drivers to make a quick emergency stop using the ABS. With some engine options, the ABS fluid return pump is also brought into action to provide additional boost.

At the front wheels, the latest Continental Teves fist frame brake calipers convert hydraulic force into braking performance. The unique design of these calipers allows the use of brake disks that would normally require a much larger wheel. The result is outstanding deceleration without any of the disadvantages associated with large wheels such as higher cost and additional unsprung weight. Continental Teves also supplies front-axle brake hoses for the Passat.

The Passat uses Continental Teves sensors to feed information on the speed of each wheel to the electronic brake system. This data is essential for the ABS, the traction control system (ASR) and the electronic stability control system (ESC). Precise information on wheel rotation direction and speed allows these systems to keep wheel slip in the ideal range for optimal traction under all conditions.

Precision wheel-speed sensors are also a key element in the new Passat's Deflation Detection System (DDS). This system detects loss of air pressure in a tire by continuously comparing the speeds of the four wheels. Simply put, a deflated tire turns faster than a fully inflated one. Continental Teves supplies both the wheel speed information software and the sensors.

Durable quality: rubber, plastic and hoses

Making quality visible -- ContiTech company Benecke-Kaliko has put this principle into practice in the new Passat by developing very high-quality trim components. For example, Benecke-Kaliko supplies plastic foils for the instrument panel, door trim panels and the interior trim of the luggage space. These components are designed for long service lives and are extremely durable even with little care. They give a high-quality look to interior areas that drivers and passengers touch and see every day, and retain their finish even after many years of use.

Where reliable and robust technical systems and components are required, Volkswagen has also opted for ContiTech products. Parts supplied by ContiTech for Volkswagen's new mid-range Passat include axle boots and shock absorber bellows, as well as transmission oil cooler piping, turbocharger lubrication lines and air conditioning lines, all designed to help these systems offer long service lives with no repairs. High-performance V-belts and V-ribbed belts drive ancillaries, and ContiTech bearings and dampers minimize unpleasant vibrations.

With 2004 sales of approximately $15.6 billion (US), Continental AG is a major supplier of brake systems, chassis components, vehicle electronics, tires and technical rubber products. Continental Automotive Systems' North American operation is headquartered in Auburn Hills, Mich. and is a leading global supplier of quality automotive systems that contribute to driver safety, comfort and peace-of-mind. For additional information, visit our media website http://www.contitevesna.com/index2.htm .