6 cylinder low lift mode
The powertrain control module (PCM) switches rocker arm oil control solenoid A (bank 1), solenoid B (bank 1), and solenoid A (bank 2) to OFF. On the rear bank side, the pressurized oil from the oil pump passes through the VTEC spool valve and flows into the rear rocker arm. On the intake side, the hydraulic pressure acts onto the right side of synchronizing piston B in the figure, and stopper piston A and synchronizing piston B are moved to the left side in the figure by the spring force and the hydraulic pressure. By doing this, the intake primary rocker arm and the intake secondary L rocker arm are synchronized and joined. Low lift drive is done by the cams having the small valve lift. On the exhaust side, the hydraulic pressure acts onto the spring side of exhaust synchronizing piston, and by using the spring force and the hydraulic pressure to move synchronizing piston B and exhaust synchronizing piston in the direction of the arrow in the figure, the exhaust primary rocker arm and the exhaust secondary rocker arm are synchronized, causing them to move as one. On the front bank side, the hydraulic pressure from the oil pump is not applied to the rocker arm piston because the spool valve is pushed up by the spring force. The rocker arm piston is pushed by the spring force to the left side in the figure, the intake primary rocker arm and the intake secondary rocker arm separate, and a low lift movement is done by the cams having the small valve lift.