Press Release
Highlights in vehicle dynamics
- Top model comes with standard DCC adaptive chassis control
- Lane Assist with active steering boost for greater comfort and safety
- aptive chassis control and new generation of 4Motion perfect the car’s performance
The Passat CC is being offered with numerous new and innovative vehicle dynamic technologies. A highlight here is the “Lane Assist” lane keeping assistant being introduced for the first time on a Volkswagen. The system is able to assist with a corrective steering intervention to help keep the car in its lane. Of course, the system does not relieve drivers of their responsibility for diligent control of the vehicle.
Another new technical feature is DCC adaptive chassis control. The adjustable chassis is a standard feature on the top model of the new car series, the Passat CC V6 4Motion. Adaptive chassis control offers three different programs. Crucial here is the fact that the adaptive chassis control system improves driving characteristics across the board. That is because the suspension is constantly being adapted to the roadway and driving situation. Also standard equipment aboard the top model is the latest generation of 4Motion full-time all-wheel drive, which underwent significant advanced development. The results: greater dynamics and optimized active safety.
Another high-end technology is the “Park Assist” parking assistance system. It automatically guides the Passat CC into a parking space parallel to the roadway at the push of a button. The driver no longer needs to steer in this case, but instead just accelerates and brakes. In addition, there is the “ACC automatic distance control”, which is familiar from the “classic” Passat. When “ACC” is activated the Passat CC automatically brakes and accelerates within a speed range preset by the driver (0 to 210 km/h). Thanks to “Front Assist”, the system can also prevent some cases of frontal collisions. In advance of certain situations the system preventatively puts the brakes in a preconditioned state, thereby functioning as a stopping distance reduction system (“AWV”). “Front Assist” also warns the driver of hazardous situations by visual and acoustic signals. Even more: If a minimum driving distance is not maintained, in extreme cases the system brakes the Passat CC to a stop (“follow-to-stop”). However, it does not relieve drivers of their responsibility and lets them intervene in the process at all times.
Lane Assist – the new lane-keeping assistant by Volkswagen
This active lane keeping system on the Passat CC automatically counter-steers as soon as it detects that the Passat CC could leave its lane unintentionally; a genuine gain in convenience and safety. The reason: About 14 percent of all accidents involving injuries are caused by a vehicle leaving its driving lane. “Lane Assist” can make a contribution toward reducing this accident rate. By the way, if the driver sets the turn signal to intentionally change lanes, “Lane Assist” does not intervene. The system is activated via the multifunctional display on the Passat CC. The driver selects the system under the “Lane Assist” menu item to activate it. As long as the driver does not deactivate the system, from that point forward “Lane Assist” takes effect starting at a speed of 65 km/h. “Lane Assist” detects lane markings via a camera in the vicinity of the rearview mirror or rain sensor. It does not matter whether road lines are continuous or broken as in the case of a center stripe. “Lane Assist” also operates in darkness. However, the system does not intervene when there are no lane markings.
Once “Lane Assist” has been activated, the driver is informed by a yellow indicator symbol in the shape of a driving lane in the instrument cluster. As soon as the camera has acquired the proper lane markings, the symbol lights green. Now the system is fully active. As soon as the system indicates that the car is leaving the ideal line, “Lane Assist” counters by steering in the opposite direction. Decisive here: counter-steering is very continuous and gentle. If the driver takes his or her hands off the steering wheel entirely, the system detects this and issues a warning, both acoustic and by a text message in the instrument cluster – a so-called request to resume control – and if the driver does not resume steering the system switches itself off after eight seconds.
Similarly, the driver can always “override” the “Lane Assist” steering with just a little force. The lane keeping assistant does not react when the driver activates the turn signal before crossing over a lane marker either. Incidentally, “Lane Assist” functionality is only possible if the car has “controllable” electro-mechanical power steering, such as the Passat CC has as standard equipment.
DCC adaptive chassis control – more dynamics and comfort
When it comes to the chassis, a gain in truly perceptible sportiness always comes at the expense of comfort, and the opposite holds true as well. It would therefore be ideal to have a chassis that could continually adapt to roadway conditions and the specific wishes of the driver or car passengers. However, that requires an electrically adjustable suspension. This new “adaptive chassis control” by Volkswagen is offered as standard equipment on the Passat CC V6 4Motion. Not only is the suspension’s damping characteristic controlled, but the electro-mechanical power steering is tuned as well.
“Adaptive chassis control” offers three programs: “Normal”, “Sport” and “Comfort”. “Sport” and “Comfort” are selected by a pushbutton to the right of the gearshift lever. Decisive here is the fact that driving characteristics are improved by adaptive chassis control continually. That is because the suspension constantly adapts to the roadway and the driving situation. The system also reacts to acceleration, braking and steering inputs. This resolves the conflict in objectives between a stiff sporty suspension and a comfortable suspension. For drivers and their passengers this makes itself felt in significantly improved ride comfort.
In the “Sport” program, on the other hand, the Passat CC is transformed into an agile sports car, since the suspension is stiffened considerably; and simultaneously power steering boost is reduced with more direct layout. The opposite is the case in “Comfort” mode. Comfort is significantly improved, especially on poor roadways and during slower driving; the suspension characteristic is then similar to that of a luxury sedan in the style of the Phaeton.
Components of the new “adaptive chassis control” system include four dampers with characteristic map control, a gateway control module that serves as an interface to the CAN data networks in the Passat CC, three sensors for measuring wheel displacements, three sensors for measuring movements of the car body and a control module for suspension control. The “Normal”, “Sport” and “Comfort” modes are also indicated in the instrument cluster.
4Motion – the latest generation of all-wheel drive
A standard feature on the Passat CC V6 4Motion is the latest generation of Volkswagen’s all-wheel drive system. 4Motion has undergone significant advanced development compared to the version implemented to date. Above all, the transfer of power between the front and rear axles – and therefore the all-wheel clutch – exhibits significant advances compared to the prior generation. The most important of these: activation of all-wheel drive no longer requires a speed difference between the front and rear axles. The result: additional gains in active safety and dynamics.
Details of the 4Motion system on the Passat CC: the electro-hydraulic all-wheel clutch runs in an oil bath. Different than on the preceding generation, pressure buildup is handled by an electric pump. The multi-plate clutch system itself was integrated in the rear axle drive. The electric pump delivers oil to the pressure reservoir whose working pressure is 30 bar. An ECU computes the ideal drive torque for the rear axle and regulates, via a valve, how much oil pressure is transmitted to the working piston of the multi-plate clutch. In this process, the contact pressure on the clutch plates is proportional to the torque desired at the rear axle. The transferable torque can be continuously varied by the magnitude of the pressure applied to the clutch plates. Compared to the previous 4MOTION generation, the system operates as a function of slip, since the working pressure is always available. When starting up from a stop and accelerating, slip of the wheels at the front axle is prevented even more intensively, since the ECU controls torque distribution based on dynamic axle loads. In extreme cases, it is still possible to direct nearly 100 percent of the drive torque to the rear axle.
Basic layout of the Passat CC chassis:
The Passat CC shows just how a modern front-wheel drive or all-wheel drive chassis should perform in terms of both its comfort and handling properties. The four-link rear suspension that is acoustically decoupled from the car body via a subframe, the McPherson front suspension designed with aluminum components and electro-mechanical power steering all guarantee agility, comfort and safety of the highest level.
The chassis technology is perfected by the ESP system with integrated trailer stabilization that is standard equipment worldwide. Going beyond familiar ESP functions, when a trailer is being towed the system ensures early detection of the dreaded trailer swaying and reduces it by specific brake and engine interventions.
Front suspension:
The front suspension of the Passat CC is based on the McPherson principle with lower mounted A-arms and MacPherson struts. This suspension is very light and therefore offers numerous advantages. In the area of the especially rigid and crash-optimized suspension subframe alone, 4.5 kilograms of weight were trimmed compared to a conventional sheet steel design. Also very light are the transverse links manufactured from forged aluminum. Here the weight advantage compared to sheet steel is a total of 4.2 kilograms. Lightweight construction methods are especially beneficial when it comes to unsprung masses. Therefore, besides the transverse links, the linkage bearings are also made of aluminum. The weight advantage here adds up to 3.2 kilograms. Thanks to a special design, it was also possible to save 1.4 kilograms of weight in the area of the stabilizer. The various lightweight construction methods reduce the weight of the front suspension by a total of 13.3 kilograms. And that means: greater comfort, more dynamics and better fuel economy.
Rear suspension:
The Passat CC has a four-link rear suspension. It is also very light and offers a high degree of ride comfort and stability. A special layout of the links makes it possible to tune longitudinal and transverse dynamics separately. The separation of functions ensures optimal dynamics and driving safety on the one hand, and very impressive ride comfort on the other.
The four-link rear suspension consists of a decoupled subframe to which the steering knuckle is connected via the spring arm, tie rod and transverse arm upward in a transverse direction. Wheel locating in the longitudinal direction is handled by the trailing arm. Also used on the rear suspension are weight-optimized tube stabilizers. Decisive for the very good comfort of the Passat CC is the fact that the rear suspension is decoupled from the car body via the subframe. This isolation is accomplished by four rubber-metal bearings. The bearing’s rubber mixture was selected to satisfy the special dynamic requirements during driving operation in an ideal way. The result: isolation of the subframe elevates acoustic comfort and driving and ride comfort to luxury class levels.
