We buried my grandfather recently. A clockmaker by trade, his one claim to fame was to have made a sea-going chronometer in which he guaranteed the mechanism would never wear out. Since I am now saddled with honouring that guarantee, should it prove necessary, I decided to have his headstone engraved with the phrase 'Hope springs eternal'.
Grandfather spent a lot of his time repairing clocks, and whenever customers brought him one to repair their inevitable diagnosis was '" The spring's gorn." In fact, that was seldom the case but since most people know very little about the inner workings of a clock, they would blame the only bit they'd ever heard of.
I often encounter the same degree of misunderstanding whenever people talk to me about cars, and the subject of springs arises. In my experience, most folks think that the sole purpose of car springs is to stop the body rubbing on the tyres. The more informed generally suspect that springs are there to provide a smooth ride. That's true up to a point, although absorbing road shock is arguably the least important function of springs.
More vitally, springs are there to keep the wheels on the road, forcing them back down whenever they lift off the road surface as a result of bumps or exaggerated driving. Think about it. Your car is designed to operate safely when all four tyres are in contact with the road. Every time a tyre loses that contact, traction, handling and roadholding are compromised, potentially with dire results.
But springs behave in strange ways, especially coil springs. Left to their own devices, they would expand, contract and recoil in a random fashion, like Zebedee on illicit substances. Any car so equipped would be almost impossible to drive. These reactions need to be attenuated, dampened, if you like, using shock absorbers. These 'shockers', or 'dampers' usually take the form of gas-filled struts that are located within the spiral of the coil spring and attached to each end.
So far so good, but who decides how much they should 'dampen' the reactions of the coil spring? Usually the car designer, who will specify a soft, medium or hard setting according to the overall characteristics he wants to obtain. Traditionally, limousines will have fairly soft settings and sports cars quite the opposite, with family cars somewhere in between. As a general principle, the harder the damper settings (and to some extent, the springs), the better the road holding.
But what if the car has more than one character, like, for example, the new Volvo V70R? Loaded with premium, family-car brand characteristics that demand a soft-ish ride, it is nonetheless capable of very high speeds when stiffer dampening is more appropriate. Enter Volvo's 'Four-C' active chassis technology, which not only allows the driver to choose between three different damper settings, but also responds to an array of sensors dotted around the car that measure things like yaw and pitch, steering input, and lateral and linear acceleration.
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