6 Series 650i (N62TU) Coupe
The pulsating air column inside it increases torque in the medium engine speed range considerably.
To increase performance in the higher engine speed range, the sliding sleeves are opened. This largely reduces
the dynamics in the front intake pipes. The short resonating pipes which are now effective can make high
performance figures in the upper engine speed range possible.
The DME control unit adjusts the sliding sleeves via the two DISA servomotors (12 volts) with integrated
transmission. Each DISA servomotor has one output stage. The information as to whether a downwards or
upwards gearshift was made is saved by the DME control unit.
When the value falls below 4700 rpm, the DME control unit closes the sliding sleeve with the assistance of the
DISA servomotors. When the value of 4800 rpm is exceeded, the sliding sleeves are opened again
(N62B40TU: 4800 and 4900 rpm). At changeover, these engine speeds are displaced reciprocally (hysteresis)
to prevent the sleeves opening and closing in rapid succession.
In the event of system failure, the sliding sleeves remain in their respective positions. The driver will be aware of
system failure through a loss of power and reduction in the final speed.
Once the engine has been switched off (terminal 15 OFF), the sliding sleeves are run once to their limit position.
This prevents deposits accumulating and blockage of the sliding sleeve during longer journeys at low engine
speeds.
[more ...]
Charge monitoring
The following input variables are used to monitor the charge state of the DME:
•
Throttle-valve angle
•
Valvetronic lift
•
Air intake pressure
•
Intake air-mass
From these 4 input variables on the inlet side, the DME calculates the charge state for all operating conditions.
"Valvetronic" variable valve gear
Valvetronic was developed to reduce fuel consumption.
The quantity of air supplied to the engine when Valvetronic is active is adjusted by the variable valve lift on the
inlet valve and not the throttle-valve actuator.
An electrically-adjustable eccentric shaft changes the action of the camshaft on the roller cam follower via an
intermediate lever. The result of this is variable valve lift.
With Valvetronic, the throttle-valve actuator is activated for the following functions:
•
Engine start (warm-up)
•
Idle speed control
•
Full load operation
•
Emergency operation
In all other operating conditions, the throttle valve only remains open far enough to induce a slight low pressure.
This low pressure is required to ventilate the tank, for example.
The DME control unit calculates the associated setting of Valvetronic using the position of the accelerator pedal
and other variables.
The DME control unit activates the Valvetronic actuator motor on the cylinder head via the Valvetronic control
unit. The Valvetronic actuator uses a worm gear to drive the eccentric shaft in the cylinder head oil chamber.
The eccentric shaft sensor records the current position of the eccentric shaft. The eccentric shaft sensor is
SBT 8-cylinder spark-ignition engine N62TU E60, E61, E63, E64, E65, E66, E70
BMW AG - TIS
19.01.2013 07:31
Issue status (12/2007) Valid only until next DVD is issued
Copyright
Page - 13 -
