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Automated Manual Transmission
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System Operation (In the Absence Of
Faults):
Pressurisation of the Hydraulic Circuit:
When the pressure is below the minimum
operating threshold, pressurisation of the
hydraulic circuit occurs in two different ways:
When the driver's door is opened the sys-
tem automatically pressurises the hydraulic
circuit until the pressure value is such to al-
low, if requested, the subsequent vehicle
start-up: therefore, when requested, the
system must be ready to open the clutch
and engage the neutral without waiting for
the hydraulic circuit to be pressurised
(WAKE-UP condition).
With key on IGNITION ON: the system con-
trol unit is supplied (and will remain
powered until the key is turned to OFF and
the vehicle and engine speed is zero).
Automatic Engagement of the Clutch Down-
hill With the Accelerator Pedal:
Released:
If the vehicle, with gear engaged, accelerator
released and engine started picks up speed
because it is going downhill, when a pre-set
speed is reached, it automatically closes the
clutch to provide the vehicle with engine
braking.
If the driver presses the accelerator pedal,
the torque transmitted is once again con-
trolled directly by the driver.
This automatic engagement of the clutch is
interrupted if the vehicle moves in the oppo-
site direction to the engaged gear.
Vehicle Slowdown
In a slowdown situation, for example with
gear and accelerator pedal released, the sys-
tem automatically disengages the clutch to
avoid the shutdown of the engine when the-
se come close to the system's idling value.
This disengagement takes place at an engine
speed that depends on the level of decelera-
tion and driver controls (brake pressed or
otherwise). However, the transmission au-
tomatically shifts down if a gear higher than
2nd gear is engaged during deceleration.
When the vehicle is stationary, 1st gear is au-
tomatically engaged.
The clutch is opened only if the brake is
pressed. When the brake is released, the
clutch remains closed and the vehicle runs at
idling speed. This function is only enabled for
the 1st and 2nd gear.
Turning Off the Engine and System:
By turning the key to the STOP position the
engine is turned off and the system retains
any gear engaged.
The system deactivates only after the three
speeds are zero: engine, gearbox input, gear-
box output and after having saved the
functional and diagnosis data on the stable
memory of the control unit (EEprom).
It switches off after a maximum of around 10
seconds with the vehicle stationary and the
engine switched off.
Functional Interaction Logics with Other Sys-
tems:
The system interacts with other systems ac-
cording to the logics shown below.
Interaction with Engine Management:
When driving the two systems do not inter-
act, because the system does not perform
any work, therefore only information and
signal exchange persists.
During a gear change, the system must be
"master" with respect to engine manage-
ment, i.e. the gearbox control system must
ask the engine (through the CAN network)
what the engine torque should be (decrease
while the clutch is open and increase when
the gear change is complete and the clutch is