PART ONE
In the first of our new series exploring Jaguar technology, we revisit the workings of the adaptive damping system marketed as Computer Active Technology Suspension
I WAS chatting recently with former Jaguar engineers who had been involved with the development of the firm’s road cars from the mid-’80s right up to the aluminiumbodied XJ of 2002 and naturally the subject of ride and handling came up.
Jaguar may have had its issues, especially in the BL era when quality was suspect to say the least, yet one thing the firm always managed to offer was aride and handling balance which was pretty unique in the market. The Mk2 and its predecessors may have been unremarkable in this regard, but once the famous independent rear suspension had been developed, Jaguars managed to combine capable roadholding with aremarkable composure, something which was first offered in the S-Type of 1963 when road testers all remarked on how much more comfortable and capable it was asahigh-speed long-distance cruiser.
This unique Jaguar selling point would help the firm through some dark times when industrial unrest meant production quality was at rock bottom and for example, even when the XJ-S and Series 3 XJ were in the twilight of their production lives they were still winning praise in magazine group tests for the quality of their ride and handling.
Fashions were changing though and by the early ’90s a 15-inch rim with tall tyre sidewalls was increasingly looking old hat as tyre profiles shrank and wheel diameters increased. A new era was beginning where a car couldn’t be considered sporting unless it offered a rock-hard ride –atleast if it was German anyway –and Jaguar was in danger of losing its signature feature infollowing the fashion for 18-inch rims and 30-profile rubber.
However, this was also an era when electronic control in the automotive world was just gaining pace and active ride systems had already been demonstrated: Lotus had demonstrated a full active ride system on an Esprit as early as 1983 and in 1994 Citroën developed its Hydractive system into a production car as the Xantia Activa –both cars offering entirely flat cornering.
In practice though, full active ride systems weren’t quite what the market wanted and indeed the Lotus system never made it to production, while many Activas ended up in ditches when the lack of cornering sensation encouraged drivers to exceed the limits of grip and general laws of physics.
What was wanted was a solution aimed more ataddressing everyday practicalities, specifically how to offer a soft ride during gentle driving on average roads, but firm up the suspension when the car was driven in a spirited manner and for this, automatic control of the dampers was ultimately the answer.
Yes, adjustable dampers had been around for along time –since the very dawn of
