Variable Valve Timing

For each intake camshaft there is a variable valve timing unit, a bush carrier assembly and a solenoid/shuttle valve.
It is an infinitely variable system (within the prescribed operating range) operating on the intake camshafts only. There is the equivalent of 48° of crankshaft movement between the retarded and advanced positions. Engine oil pressure operates the system under the control of the ECM.
The variable valve timing system improves both low speed and high speed engine performance, engine idle quality and exhaust emissions. Engine idle is improved due to the ECM being able to retard the valve timing by an additional 10° compared to the previous VVT system; this also reduces the internal EGR at idle, where it is not required. However, the internal EGR system is improved at normal engine running speeds to reduce NOx emission and eliminate the need for any external EGR system components.