Continuous Variable Valve Timing (CVVT) valve

Fig 1: Camshaft Control

Courtesy of VOLVO CARS OF NORTH AMERICA.

The Continuous Variable Valve Timing valve has three connecting channels and a return channel.

Counted from the front of the valve these are:

• - Return terminal
• - Continuous Variable Valve Timing unit rear chamber terminal
• - Engine lubricating system pressure terminal
• - Continuous Variable Valve Timing unit front chamber terminal

Inside the Continuous Variable Valve Timing valve there is a piston housing with a spring tensioned piston. The piston housing has three machined grooves with holes drilled into the piston housing center. The piston housing grooves are connected to the Continuous Variable Valve Timing valve three rear connections.

The Continuous Variable Valve Timing valve piston has a channel connecting the pistons front and rear grooves in the center. The piston housing rear groove is connected to the valve return terminal. The front piston groove is wide enough that it can connect one of the piston housing outer groove with the center or stop in a center position where none of the outer grooves are connected.