Maserati Quattroporte Automatic 2009 Owner's Manual page 159

M139_UM_usa1.book Page 159 Monday, September 1, 2008 2:39 PM
Strategies during downhill driving
When the accelerator pedal is
released, the gearbox system detects
that the vehicle is moving downhill
and deactivates upshifting. When the
accelerator pedal is depressed,
upshifting is reactivated but will be
delayed by a few seconds.
When the brake pedal is depressed,
the gearbox system downshifts to
provide enhanced engine braking
power.
In other words, when driving downhill,
the gearbox system operates so as to
avoid upshifting and shifting gears
when the accelerator pedal is released,
and delays gear engagement by a few
second when the accelerator pedal is
depressed. In addition, when the
brakes are applied, it engages the
lowest gear in order to provide
enhanced engine braking power.
This strategy is aimed at making
downhill driving safer.
Strategies in curves
The system detects when the vehicle
goes into a curve through the lateral
acceleration and the steering angle.
Detecting this condition, it controls
gearshifting using a specific mode.
This mode is exited when the vehicle
comes out of the curve, at a distance
that varies depending on the vehicle
speed.
Fast-off strategy
When the accelerator pedal is fully
released, the system deactivates
upshifting.
When the accelerator pedal is next
depressed, upshifting is reactivated
only after a few seconds.
Upshifting is also deactivated when
the accelerator pedal is partially
released; the system waits the time
necessary to evaluate if the release
action is completed.
Hot-mode strategy
In the event that the engine oil or
coolant temperature is too high or
both, the gearbox system reduces the
maximum engine speed to 4000 RPM.
Therefore, upshifting will occur at this
limit.
This strategy does not manage
downhill driving, so as to always have
the efficiency of engine braking
together with the standard braking
system.
MSP system operations
In order to prevent unstable driving
conditions, the MSP system may
request the gearbox system to
deactivate gearshifting. The system
handles this request depending on the
gear engaged and on the RPM, and
decides whether to accept it or not.
Cruise Control
With cruise control the gearbox system
selects such settings as to provide
enhanced comfort and fuel-economy.
Electronic automatic gearbox
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