VOLVO I-SHIFT !!

Transmission:

I-Shift, AT2412C, is a 12-speed manual gearbox with an automatic gearchanging system. IShift is designed for tourist, intercity, regional and route operations, where it provides high driving and ride comfort and excellent fuel economy.

I-Shift is a fast-responding gearchanging system with minimum interruption in torque delivery during changes and a wide ratio span, a combination that offers impressive resources for high average speeds. The system consists of a non-synchromesh manual gearbox with an electronically regulated pneumatic gearchanging system and an automatic clutch. The gear selector is integrated with the driver’s seat and gearchanges are fully automated. Starting ratio is selected automatically in response to road gradient and gross vehicle
weight. I-Shift is available with a choice of program packages and various functions. Among them is a facility for choosing between fully automatic gearchanges and manual selection, and a performance mode with a kickdown function that utilises the engine’s capacity to the maximum.The transmission is a compact, lightweight unit. It is divided into a base unit and a range-change unit. The base unit, range
section and clutch housing are made of aluminium, which contributes to the low weight. The transmission is factory-prepared for installation with or without a compact retarder (VR3250). Long oil-change intervals mean low operating costs and less environmental effect. When special oils are used, oil and filter
changes take place after a maximum of 400,000 km or every third year.

electronic control for high oPerating reliability:
The gear selector and lever are conveniently integrated with the
driver’s seat. There are two variants, with or without the option of manual changes. The gear lever has no mechanical contact with the gearbox; instead, the lever’s movements act on a number of sensors in
the gear selector.
The gear control system is integrated into the base unit and contains an electronic control unit, solenoid valves, gearchanging cylinders, shift forks and sensors.flexible gearchanging system gives good driveability
I-Shift is a flexible gearchanging system supported by extremely powerful software. Since the clutch function is regulated by the gearchanging system, there is no clutch pedal. The graphic display shows
the driving program selected, the available ratios up and down, the
lever’s position and the selected gear.
In the A setting, gearchanges take place entirely automatically, even
when the cruise control is activated. The M setting locks the current
gear or permits manual changes.
In Automatic mode, the driver can choose between the “Economy”
and “Performance” programmes. The “Limp-Home” function makes it
possible to continue driving the vehicle even if there is a fault with the
transmission’s or the clutch’s position sensor.
The various program packages have different functions that optimise the bus for its particular application area. EcoRoll with Smart Cruise
Control for tourist coaches, for instance, is a function that gives additional fuel savings, while Launch Control helps the driver both when
starting on an uphill gradient and when manoeuvring at low speeds.

sturdily dimensioned comPonents
The base unit contains three base ratios, an integrated splitter gear
and reverse gears. The range-change section contains a range gear
of planetary type. The splitter and range gears are synchronised, while the base unit has no mechanical synchromesh. Revs are instead
synchronised with the help of the engine’s and the transmission’s control units before the next gear is engaged.
All the shafts, bearings and gears are sturdily dimensioned for high
operating reliability and long service life. All the gears are made of
special steel that has been case-hardened to provide considerable strength. The gears in the base unit are helical, so more teeth are in mesh with each other at any one time. This results in quiet operation and high operating reliability. integrated sPlitter gear and range-change gear of Planetary tyPe The splitter gear, which is a compact and sturdily journalled unit, is fitted on the input shaft in the base unit’s forward section. The splitter gear halves the ratio between two base gears. The range-change gear
consists of a sturdily dimensioned planetary unit with helical gears and
a new synchromesh system, fitted after the base unit.
factory-PrePared for retarder
The transmission is factory-prepared for installation of hydraulic retarder VR3250, which offers high braking power of 400 to 600 kW.
Certain program packages have a function called Enhanced Shift
Strategy. It momentarily applies the wheel brakes as the transmission
changes down during engine braking. This function is combined with
the Electronic Brake System (EBS) to provide powerful and gentle
engine braking


sPecifications:
Type designation AT2412C
Max incoming torque 2400 Nm
Weight without oil 269 kg
Weight without oil incl. retarder 369 kg
Type Automatic splitter/
range-change transmission
Number of forward gears 12
Number of reverse gears 4
Gear selector positions:
R Reverse
N Neutral
A Automatic
M  Manual/Hold
Driving programs:
E Economy program
P Performance program
L Limp Home function
Oil-change volume approx. 13 l