Hydraulic Control

The ECVT 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:

• Flow to and from the primary pulley is controlled to command the correct transmission ratio for all driving conditions.
• 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.
• 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.
• 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. This is needed for take off.