May 092013

The hydraulic system is the part of the Selespeed that in the practical sense, has the task of the selection – engagement of the required gear.

Basically it consists of:

  • A power group to pressurise the circuit
  • Two actuators to control the gear shaft
  • An actuator to control the clutch
  • Sensors for system monitoring by the control unit

The hydraulic system has these functions:

  1. To supply the hydraulic energy needed to control the actuators
  2. Gear shaft control
  3. Clutch control

The fundamental function of the hydraulic system is to supply the hydraulic energy to control the actuators (gear change). Therefore the possibility to change gear is tightly bound to the pressure of the oil in the circuit, with values between 45 and 55 bar.

The main technical specifications that are necessary for the system to ensure correct operation are:

  • Hydraulic working pressure between 45 and 55 bar (there is a pressure relief valve to avoid system over-pressure)
  • Working temperature between -30°C and +125°C
  • Starting must also be possible with a temperature of -30°C
  • The pump flow rate must be 0.8l/min at 60°C
  • The accumulator volume must be 350 cm3 at 20°C (this value is important because it determines the discharge time)
  • The oil used is Tutela CS Speed.
Hydraulic System

Hydraulic System


  1. Electro-hydraulic group
  2. Oil pump
  3. Oil tank
  4. Oil inlet pipes
  5. Discharge pipes
  6. Accumulator
  7. Oil pressure sensor
  8. Oil bleeding screw
 Posted by at 11:08 am