May 092013

As can be seen from figures 5 and 6, the CFC 208F control unit, before each gear change, activates the clutch (1) by a servo actuator and a solenoid valve (EV0) controlled by the control unit.

The control function of the gear shaft takes place in these steps:

  • Selection lever activation
  • Transmission of the selection lever position to the control unit
  • Activation of engagement lever
  • Transmission of the engagement lever position to the control unit

The components involved in the gear change are:

  • Selection actuator
  • Selection potentiometer
  • Wiring harness between selection potentiometer and sectioning connector
  • Selection solenoid valve EV3
  • Wiring harness between selection solenoid valve EV3 (gear selection range 1-2) and the sectioning connector
  • Selection solenoid valve EV4
  • Wiring harness between selection solenoid valve EV4 (gear selection range 5 – R) and the sectioning connector
  • Gear engagement actuator
  • Engagement potentiometer
  • Wiring harness between engagement potentiometer and sectioning connector
  • Engagement solenoid valve EV1 (to engage odd gears 1-3-5)
  • Wiring harness between engagement valve EV1 and the sectioning connector
  • Engagement solenoid valve EV2 (to engage even gears 2-4-R)
  • Wiring harness between engagement solenoid valve EV2 and sectioning connector.
Section of clutch control - gearbox actuators

Section of clutch control – gearbox actuators


  1. Clutch control lever on gearbox
  2. Gear shaft (engagement and selection control)

Hydraulic System – Diagram

Hydraulic diagram

Hydraulic diagram


  1. Engagement solenoid valve 1
  2. Engagement solenoid valve 2
  3. Selection solenoid valve 3
  4. Selection solenoid valve 4
  5. Clutch solenoid valve
  6. Electric pump
  7. Delivery filter
  8. (Don’t know what is this, please leave a comment if you know)
  9. Check valve
  10. Accumulator
  11. Oil tank
  12. Clutch actuator
  13. Engagement actuator
  14. Selection actuator
  15. Pressure sensor
 Posted by at 1:25 pm
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