VTEC/VTC - Construction(K24Z7/K24V7)
VTEC
VTEC is composed of the VTEC camshaft, the VTEC rocker arm, and the rocker arm oil control valve.
VTEC Camshaft
The cam shaft is structured so that each cylinder has an low lift cam lobe and high lift cam lobe separately.
VTEC Rocker Arm
The rocker arm is divided to the primary part, the secondary part and the medium part. The inner side of the intake secondary rocker arm has a VTEC switching piston and a return spring.
Rocker Arm Oil Control Valve
The rocker arm oil control valve are integrated with the cylinder head.The rocker arm oil control solenoid turns ON or OFF the solenoid depending on a signal from the PCM to switch the hydraulic pressure applied to the valve to subject the valve to an ON/OFF control. By switching the ON/OFF of the valve, the hydraulic pressure applied to the VTEC switching piston in the rocker arm is controlled.
VTC
VTC is composed of the VTC actuator, the VTC oil control solenoid valve, and the CMP sensor A.
VTC Actuator
The VTC actuator is composed of a vane part that is operated by hydraulic pressure and a housing that is integrated with a timing gear, and is installed at the intake camshaft.
When the engine stops, the vane is fastened at the fully retard position by the lock pin so that the engine will start smoothly next time. After the engine starts, the vane turns to be free because the lock pin is set back against the spring tension by the oil pressure.
VTC Oil Control Solenoid Valve
According to the signal from the ECU, the VTC oil control solenoid valve applies the oil pressure on both VTC advance chamber and VTC retard chamber in the VTC actuator to rotate the vane, and then a continuous change of the phase in the intake camshaft will occur. Also, a metal strainer is attached to the VTC oil control solenoid valve in order to prevent foreign substances from being caught in the middle.
CMP Sensor A
CMP sensor A detects camshaft angle position for the VTC system.