DoubleVANOS

Double VANOS is a variable valve timing system developed by BMW. It is an advancement of their earlier VANOS system, which only controlled the intake camshaft. Double VANOS, introduced in the mid-1990s, allows for independent adjustment of both the intake and exhaust camshafts relative to the crankshaft. This dual control enables the engine control unit (ECU) to optimize valve timing across a wider range of engine speeds and loads.

The system typically operates by using hydraulic pressure, controlled by solenoids, to rotate the camshafts within a specific range of angular adjustment. By altering the timing of valve opening and closing, Double VANOS can improve engine performance, fuel efficiency, and emissions. For instance, at low engine speeds, it can advance the intake timing to enhance torque. At higher speeds, it can retard the intake timing and adjust the exhaust timing to maximize power output. This dynamic adjustment helps to keep the engine running more smoothly and efficiently under various operating conditions.