 |
| Think
all you need for quick, safe stopping is powerful brakes? Think
again. |
|
Cars may have
got a lot faster in the last 20 years but not much has changed in the braking
department. The only exception here has been the introduction of anti-lock
brakes.
Continental AG intends to make up some of that lost ground by linking several
strands of technology. Its ‘30-metre car’ combines the very latest
in braking, suspension and tyre technologies to cut the stopping distance
of a car travelling at 100kph from 38.5m to just 30m on a dry road. At the
heart of the Volkswagen Golf being used is Continental’s experimental
electro-hydraulic brake (EHB) - a brake-by-wire system using an electronic
pedal box to relay signals to a hydraulic control unit (HCU). The pedal
box module incorporates processors which analyse how quickly and how hard
the driver has braked, then the HCU applies the appropriate amount of brake
pressure. T
 |
| Like
a cat's paw, Continental's new tyre widens its tread area when
the brakes are applied. |
|
he true benefits of brake-by-wire are shown for the first time in the 30-metre
car. Because the brake system is electronic, it can be fully integrated
with an electronic air-sprung chassis and ‘smart’ tyres.
The chassis reduces the ride height at speed by up to 25mm, lowering the
centre of gravity which in turn allows more braking effort to be supplied
to the rear wheels without locking them up.
Shock absorbers are continually adjustable, with compression and rebound
being adjusted for each individual wheel. That minimises changes in load
on each tyre due to bumps in the road and pitching of the body.
Tyre design is obviously a crucial element too, and the 30-metre car is
clad with Continental’s latest tyre, the ContiPremiumContact. The tread
of the new tyre is designed to spread out like a cat’s paw when loaded-up,
increasing the size of the contact area and providing greater grip - invaluable
in wet conditions.
 |
| Click
on the thumbnail for a larger view of experimental EHB system
used on the VW Golf. |
|
The
tyres have also been converted by adding an experimental sidewall torsion
sensor (SWT), a magnetic strip read by sensors on the suspension.
Because the tyre sidewall distorts as the car loads up under braking or
cornering, SWT can detect not only what is happening, but what is about
to happen and can sense the onset of a skid before the tyres have even
lost adhesion.
EHB, SWT, anti-lock brakes, the electronically adjustable shocks and air
suspension all pass data to a central processor. This optimises the braking
on a wheel-by-wheel basis, ensuring maximum braking effort without any
loss of control, every time.
‘Thinking’ brakes, tyres and suspension should make drivers
less prone to being caught out, offering more safety, but without detracting
from the driving experience any more than anti-lock does now.
|
April 2001 