VVT Actuator internal gears and seals may wear over time and cause incorrect VVT operation. When the engine oil is contaminated due to extended service intervals or incorrect engine oil viscosity used during an oil service, the VVT system may create a sluggish or seized VVT actuator that can result in poor engine performance and even a no start condition.Įxcess contamination may generally cause the spool valve in the VVT actuator control valve to jam and create an excessive advanced or retarded camshaft condition.įailed electrical circuits will cause the actuator to remain in the retarded or advanced position that would depend on the spool valve position in the VVT oil control valve. Typical VVT faults and causes that affect its operation.īeing a mechanical/hydraulic system that is controlled by electronics, there are a few areas of concern if the system is not maintained correctly. The control valve integrates a solenoid and spool valve that allows engine oil to be directed to various paths. The flow control of the oil pressure is performed by the VVT actuator control valve that is operated by a pulse width modulated signal from the PCM. The VVT system generally utilises oil pressure as the internal force for the actuator to change the Camshaft phasing. How does the VVT actuator oil control valve affect the VVT system? In the E46 3-series, the Double-Vanos shifts the intake and exhaust camshaft within a range of 400 and 250 respectively. As the engine RPM increases, the valves are opened earlier to enhance Torque. This increases the vacuum and scavenging effect which improves idle quality and acceleration from a stationary condition. The BMW (VVT) Vanos system (Variable Nockenwellen Steuerung) at lower engine speeds, opens the valves later during the intake stroke. Later (more advanced) Cam Changing and Cam Phasing VVT systems are utilised to increase Torque, Power, Efficiency and Idle performance throughout the total RPM range.Ī typical advanced system is the Toyota VVTL-i with continuous cam-phasing VVT and 2 stage variable valve lift plus valve opening duration applied to both intake and exhaust valves. The variable valve timing system is now commonly fitted by most vehicle manufacturers to advance and retard the camshaft in relation to the crankshaft position within the cylinder.Įarly VVT systems were utilised to increase engine performance. What a Technician needs to know when working on or diagnosing faults on a Variable Valve Timing (VVT) system. Variable camshaft actuator for Mazda 6 GG / GY / GH LFDE 4-cyl 2.0 2.02 - 11.12 VCA-028Īriable Camshaft Actuators (VCA) Oil control Valves
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |