Hydraulic Control

The CVT is controlled by a number of valves that respond to mechanical, electrical and hydraulic inputs. The control system is designed to control the pulleys and the clutches in the following three ways:

1. Flow to and from the primary pulley is controlled to command the correct transmission ratio for all driving conditions.
2. Secondary pressure is supplied to the secondary pulley to ensure that there is always adequate clamping force onto the belt for all load conditions. A solenoid valve influences the secondary pressure control valve, optimizing the pressure and hence the belt tension between the primary and secondary pulleys. This pressure optimization improves fuel consumption.
3. The clutch control consists of:
   • Selection of the correct clutch (forward or reverse). Engagement of forward or reverse gear via the selector mechanism operates the manual valve directing oil to the appropriate clutch.
   • Control of the operation needed for take off. A solenoid valve acting on the clutch valve controls the clutch application pressure to ensure smooth clutch engagement and drive away at all throttle openings.