Detailed Info of IX-30003_L3K9124X0C VVT PHASER & OCV
Working Principle and Structure of VVT system
VVT system mainly consists of a cam phaser and an oil control valve (OCV for short). The cam phaser is the actuator of the system, and the OCV is the controller of the system.
The engine management system(also commonly referred to as the ECU) looks up the MAP map based on the signals transmitted by the throttle opening sensor, the engine water temperature sensor, the rotational speed sensor, the air flow meter, etc., and calculates the required valve timing angle under various operating conditions of the engine. The time angle, that is, the target position. At the same time, EMS calculates the actual position of the camshaft based on the feedback signals from the crank position sensor and the cam position sensor. The EMS compares the target position with the actual position and sends an actuation signal to the OCV according to the EMS control strategy to change the position of the spool in the control valve, thereby changing the oil flow direction and flow rate in the oil passage, as well as the signals such as advance, lag, and constant, are fed back into the VVT phaser cavity by hydraulic pressure to realize relative rotation between the inner stator and the outer rotor of the phaser to adjust the timing angle of the camshaft, thereby the amount of intake air (exhaust) is adjusted, and the valve opening and closing time is reached.
The OCV Oil Control Valve Structure of VVT System
The VVT system's OCV valve is a proportional valve, that is, the movement position of the spool is proportional to the PWM duty ratio provided by the ECU of the engine to the OCV coil. When the duty ratio is gradually increased, the electromagnetic force of the coil is gradually increased, the iron core assembly moves in the solenoid, and the valve core is pushed forward against the spring force. When the duty cycle signal is gradually reduced, the electromagnetic force is gradually reduced. The spool gradually returns to its position under the action of the spring force. During the movement of the spool, the valve sleeve cooperates with the valve sleeve to realize the switching of the oil passage, thereby controlling the direction and flow of the oil into and out of the OCV valve, and controlling the flow of oil flowing into or out of the oil chamber of the phaser.