Volvo S90 TWIN ENGINE 2019 Owner's Manual page 446

STARTING AND DRIVING
The kickdown function
Kickdown is used when maximum acceleration is
needed, e.g. when passing.
When the accelerator pedal is depressed all the
way to the floor (past the normal full accelerator
position), the transmission will automatically
engage kickdown, i.e. immediately shift down to a
lower gear.
If the accelerator pedal is released from the kick-
down position, the transmission will automatically
shift up again.
Safety function
The transmission control module is equipped with
a downshift protection feature to help prevent the
engine from overheating.
In some conditions, the transmission will prevent
downshifting/kickdown if this would lead to such
high engine speed (rpm) that the engine could
be damaged. If the driver still attempts downshift-
ing or kickdown at a high rpm, nothing will hap-
pen and the original gear will remain selected.
With kickdown, the vehicle can downshift one or
more steps at a time depending on the engine
speed. The vehicle upshifts when the engine rea-
ches its maximum rpm to prevent engine dam-
age.
Related information
Gear selector positions for automatic trans-
•
missions (p. 440)
444
All Wheel Drive (AWD)
All-wheel drive, All Wheel Drive (AWD), also
called four-wheel drive, means that power is dis-
tributed to all four wheels, which improves trac-
tion.
The electric motor that powers the rear wheels
enables electronic all-wheel drive functionality.
All-wheel drive reacts differently depending on
which drive mode is selected.
Related information
Drive modes (p. 446)
•
Transmission (p. 440)
•
Drive systems
Volvo Twin Engine combines a combustion
engine for the front wheels and an electric motor
for the rear wheels.
Two drive systems
Depending on the selected drive mode and
power available in the electric motor, the drive
systems can either be used separately or in tan-
dem.
The electric motor gets its energy from a hybrid
battery located under the tunnel console. The
hybrid can be charged from a wall outlet or in a
special charging station. The combustion engine
can also charge the hybrid battery using a special
high-voltage generator.
Both the combustion engine and the electric
motor can generate power directly to the wheels.
An advanced control system coordinates both the
drive systems to help optimize driving economy.