A technical article By Steve Smith
Following a major overhaul of a BMW 114i N13 engine, I saw a great opportunity to measure the control signals to the Valvetronic unit (responsible for adjusting the inlet valve lift) which utilizes a 3-phase DC brushless motor.
Valvetronic (VT) reduces fuel consumption, improves engine efficiency and reduces exhaust emissions. It allows the throttle plate to remain in a fixed position under a variety of engine operating conditions while the air intake is controlled by varying intake valve lift! With the VT actuator disconnected, the engine can run as normal, utilizing the throttle plate for conventional air intake control with a fixed (maximum) valve lift.
We have a number of PicoScope captures that reveal the operation of a Valvetronic motor assembly and its effects on intake manifold pressure.