Shifting with more brains
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• Scania has launched a "more intelligent" second-generation version of its computer-aided gearchanging (CAG) system which is said to allow faster gearshifts, improved driver control and specific shift programs for normal and heavy loads.
The latest CAG uses re-sited sensors which allow the microcomputer control box to monitor more precisely movements of the brake, throttle and clutch pedals and the output shaft. The CAG master microprocessor has been uprated.
Gearchanges have been speeded up by as much as 15% and are now quicker than any manual change, says Scania.
When pulling away from rest the driver can pick his own starting gear. The CAG computer, which continually monitors throttle position, then adapts the subsequent gearchanges to his style of driving.
As each suggested shift is signalled on the dash the driver makes the change via the small selector lever on the centre console which replaces a mechanically linked gear lever.
CAG can even be set to full automatic, when it will select and engage the gears. The driver need only operate the clutch, allowing him to keep both hands on the wheel during gearchanging.
Under the new "normal" load program engine speeds are kept within the most economical rev range for gearchanges. With CAG set for "heavy load" mode engine revs are allowed to build up higher before an upchange, and down changes are made earlier. As an added safety feature a brake pedal sensor tells the computer to indicate a lower gear for better engine braking.
A clearer dashboard display now shows the active gear displayed in the centre of the panel and proposed down and up changes flashing on either side.
As with the old CAG, the system can be set to "manual", leaving the driver to make all gearchanging decisions. But as the computer continues to monitor all gear selection, it prevents the wrong gear being selected to protect the driveline. CAG will continue to be offered as an option on all RHD models, regardless of the transmission.