Dme Control Unit; Dme Main Relay; Valvetronic Additional Relay; Valvetronic Motors - BMW N62 Series Service Training

New Generation N62 Engine

- DME control unit

The valve lift adjustment is recorded by the DME control unit and
transmitted via the LoCAN to the Valvetronic control unit, which
then implements it.

- DME main relay

The Valvetronic control unit electronics system is supplied with
voltage from the DME main relay.

- Valvetronic additional relay

The Valvetronic additional relay is a single relay on the N42 and
a double relay on the N62. It supplies the load current for the
operating motors.

- Valvetronic motors

Two DC motors are fitted to adjust the two eccentric shafts. For
adjustments, they are operated by a frequency of 16 kHz for
reasons of acoustics and in order to make exact adjustments.
In order to position the engine exactly, the polarity is briefly
reversed once the target position predefined by the DME has
been attained. This generates braking torque which immediately
stops the engine.
After this, the engine is unpowered. The eccentric shaft sensor
continuously monitors the position of the engine. The self-
locking of the engine and the worm gear prevents the engine
from being adjusted by the eccentric shaft and the valve lift
while it is unpowered.
However, if automatic adjustment does take place, this is
recorded by the monitoring and the engine is moved back to the
predetermined position.
The adjustment time required to move the engine from minimum
to maximum valve lift is 200 ms.
© BMW AG, Service Training
Course Contents/Background Material
Chapter 4 P.24