Suspension, Brakes and Tires Discussion, Article tells how CVRSS works in Item Specific Cadillac Discussion; I dont know if this is for version 1 or 2 but here it is..
Suspension refinement has ...
I dont know if this is for version 1 or 2 but here it is..
Suspension refinement has been an evolutionary process at GM's prestige division. The progression began with speed-sensitive shock absorbers in 1989, continued with the first Road Sensing Suspension (RSS) in 1993, and advanced to Continuously Variable Road Sensing Suspension (CV-RSS) in 1996. The latter system selects from an infinite number of settings over twice the dynamic range provided by RSS.
Though CV-RSS hardware is little changed for the 2000 model year, there are some highly creative software advancements. While investigating new control strategies for the Corvette's Active Handling stability system, Delphi engineers found that anticipation was the key to improved performance. Instead of waiting for the body to pitch or roll and then reacting to the disturbance, Delphi engineers formulated 16 distinct strategies that use an early prompt, such as a steering input, to initiate a damper-setting change. As a result of this approach, seemingly simple shock absorber adjustments can have a profound influence over car dynamics. Four of those strategies -- informally dubbed the WOLF (Wide Open List of Functions) algorithms -- have been implemented in the 2000 Cadillac DTS. Patent applications also have been made for 21 original concepts.
The CV-RSS system's major components are shown in the schematic at right. Data is exchanged by means of the DeVille's 10.4-kbytes-per-second bus and by a few dedicated wires that deliver critical information at a higher rate of speed. The damper controller recalculates individual damper settings every millisecond.
On the system's mechanical side are Delphi triple-tube dampers, located at each comer of the car. Response time varies from eight to 30 milliseconds depending on piston velocity. At 65 mph, a damper needs only nine inches of travel to shift from full soft to full firm.
One performance upgrade engineered for the 2000 model year applies not only to the DTS but also to DeVilles and DHS models equipped with the StabiliTrak 2.0 option. Until this year, StabiliTrak intervention was triggered by watching for any inconsistency between steering-wheel position and the vehicle's yaw rate. According to Delphi engineer Scott Badenoch, computing the rate of change of the vehicle's side-slip angle and using that parameter to trigger StabiliTrak is a superior approach. "Now StabiliTrak performance is more responsive and usually transparent to the driver," he says. Side-slip is calculated from data supplied by the sensor array.
The new WOLF algorithms apply only to the DTS model that has CV-RSS as standard equipment. In response to a major steering input, the damper controller now commands revised damper settings to enhance cornering response. The second strategy manages transient body roll after the steering input. In the third algorithm, StabiliTrak activity triggers new damper settings to minimize corner "dip" when just one brake is applied, and to avoid "bobbing up" when that brake is released (see driving impression, p. 14).
The most ambitious strategy of all is damper-setting changes capable of influencing understeer and oversteer characteristics. Delphi engineers call this suspension-based yaw control because it keeps the car responding to the driver's steering commands longer, diminishing the need for StabiliTrak (brake-based yaw control) intervention.
It's interesting to compare this bulletin with the mid-2002 and later Seville TS and Corvette Lord/DELPHI "Magnetic Ride Control" system. Google "lord magnetic rheological suspension" or "lord magnetic rheological fluid" or "delphi magnetic ride control" to learn how the engineers upgraded the CVRSS suspensions while lowering parts complexity and suspension component costs.
Unfortunately, Magnetic Ride Control did not appear as a Deville option.
MRC reacts within 1 millisecond. There are several "aggressive driving" algorithms as well as "performance shifting" built into the package, so you can get pretty crazy with a late (after Jan. 02) STS and it almost makes you forget that you're driving a FWD 4,000 lb. car. My car DOES NOT have a "Cadillac ride" by any stretch of the imagination. It's tight, especially on the country road crazies east of here . Casual highway at 70 is fine, otherwise, tight.