Citroen is known for a few things, but the most prominent technological development in its history has to be the hydropneumatic suspension from the DS. It's credited with saving Charles de Gaulle's life, and makes for a magic carpet ride regardless of how rugged or rural the roads. In an attempt to inject some of this smooth-riding magic into its modern cars, the engineers at Citroen have developed a new hydraulic cushion suspension system.
Hydraulic cushions might sound like the sort of thing you'd buy on daytime television, but they're actually a clever way to stop vibrations and noise making their way into the cabin. Conventional suspension systems are generally made up of a shock absorber, a spring and mechanical bump stops. When a car reaches the end of its suspension travel and bottoms out these mechanical stops come into play abruptly, which can make for a jolting ride over big bumps and potholes.
Rather than using mechanical bump stops, Citroen's system uses a hydraulic cushion to regulate rebound and compression. When the suspension is getting close to the end of its travel, the hydraulic cushions gradually absorb the movement rather than abruptly stopping it, allowing for greater control all the way to the end of the suspension's travel.
According to the team behind it, this system helps to create a "flying carpet" effect, where the body stays isolated from any imperfections in the road surface because the suspension can be relaxed in the middle of its travel without making it loose and crashy over big imperfections.
Although this system should improve ride quality, there's more to Citroen's search for improved comfort than just clever bump stops, because the suspension doesn't work in total isolation. Instead, a car's body also plays a role in keeping you sheltered from unpleasant bumps and vibrations from the road below.
Thanks to a unique structural bonding process, Citroen engineers say they've managed to improve overall body stiffness by around 20 percent without adding any weight. This helps to isolate it from any vibrations, and in turn makes for a more refined driving experience in the cabin. Subaru has tried to do the same thing with its new platform, which is stiffer than before.
The final piece of this smooth-riding puzzle is the seats. Considering they're where you spend 100 percent of your time in the car, it seems like a good idea to dedicate some serious time to getting them right. For Citroen, that means looking to the world of bedding to create memory seats that use polyurethane, viscoelastic and textured foams for a better ride.
Although they don't go quite as far as the German Chiropractic Association approved seats in the Vauxhall Insignia, the seats in upcoming Citroens will also take into account the curve of your back for a better driving position.
All of these features show up its Advanced Comfort Lab prototype vehicle, but Citroen says they're cost effective enough to work in production models right now.
Source: Citroen
I can vouch for their efficiency, and the reduction in suspension efficiency, especially in traction on indifferent surfaces, that ensued when they were discontinued.