Valvetronic servomotor

The air mass to the engine during throttle-free operation is adjusted by the variable valve lift and not the throttle valve. Valvetronic is driven by an electric motor. The Valvetronic servomotor is mounted on the cylinder head. The Valvetronic servomotor uses a worm gear to drive the eccentric shaft in the cylinder head oil chamber. The eccentric shaft sensor provides the DME control unit with an indication of the position of the eccentric shaft.

Fig 1: Identifying Valvetronic Servomotor, Drive Shaft And Plug Connection

Courtesy of BMW OF NORTH AMERICA, INC.

Item	Explanation
1	Valvetronic servomotor
2	Drive shaft
3	2-pin plug connection

The Valvetronic servomotor is a 12 V direct current motor. The servomotor is activated at a frequency of 15.6 kHz. The direction of rotation is reversed by the DME changing the polarity of the activation. The Valvetronic servomotor is connected by 2 cables to the DME. The maximum power consumption can be up to 40 Amperes.

The Valvetronic relay ensures the voltage supply for the Valvetronic servomotor. The Valvetronic relay is fed with vehicle voltage via terminal 87 and is actuated by the ground section of the DME. The Valvetronic relay is located in the relay carrier in the engine compartment.