3 cylinder mode
The PCM switches rocker arm oil control solenoid A (bank 1) to OFF, solenoid B (bank 1) to ON, 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 left side of stopper piston A in the figure, and stopper piston A and synchronizing piston B are moved to the right side in the figure. By doing this, the intake primary rocker arm and the intake secondary L rocker arm and the intake secondary H rocker arm are separated and a cylinder stop is done. On the exhaust side, the hydraulic pressure is applied to synchronizing piston B, and by using 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 separated, and a cylinder stop is done. 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. This causes the rocker arm piston to be pushed by the spring force to the left side in the figure; the intake primary rocker arm and the intake secondary H rocker arm are separated, and a low lift movement is done by the cams having the small valve lift.