Jun 062013
 

This generates the hydraulic energy (oil). It is fastened with vibration dampers onto the body. The electric pump consists of a gear pump of approx. 0.25 cm3 /rev, drawn by a joint from a 12V d.c. electric motor through a relay controlled by the control unit CFC 208F. The electric pump is activated when the accumulated pressure is < 45 bar and it switches off when the accumulated pressure is > 55 bar. The electric motor and the pump are fastened to each other with screws by a flange. There are two threaded holes for intake (I) and delivery (U), that are connected to the oil tank and the user respectively by pipes with flexible unions. The hydraulic tank, fitted with a filter, has a capacity of approx. 0.5 I.

Electric pump and connector

Electric pump and connector

Description

  1. Ground
  2. +12V power supply
  3. I. Inlet
  4. U. Outlet
 Posted by at 4:21 pm
Jun 062013
 

The solenoid valves manage the oil flow to the actuator chambers.
All the valves are the three-way type, they are normally discharged when not controlled.

Proportional pressure solenoid valves (EV1 and EV2)

These control the oil pressure at the two chambers of the gear engagement-disengagement double-action actuator that has three set mechanical positions according to the control combination (even number gear, idling, odd number gear). The maximum flow rate is 7 l/min with pressure differential of 10 bar. The control current ranges from 0 to 2.5 A directly controlled by control unit CFC 208F. Electrical resistance of the winding is 2.5 Ohm +/- 6% at 20°C.

Position of solenoid valves and current pressure diagram

Position of solenoid valves and current pressure diagram

ON/OFF solenoid valves ( EV3 and EV4)

These feed the oil flow to the two chambers of the double action gear selection actuator that has only two set mechanical positions (1-2 and 5-R). The maximum flow rate is 1.4l/min with pressure differential of 10 bar. They are controlled with a voltage of 12V directly from control unit CFC 208F and absorb approx. 2A.
Electrical resistance of the winding is 5.1 Ohm +/-6% at 20°C.

On-Off solenoid valve position

On-Off solenoid valve position

Solenoid valves and actuators

The solenoid valves manage the oil flow to the actuator chambers.
All the valves are three-way; they are normally discharged if not controlled.

Proportional flow-rate solenoid valve (EV0)

It controls the oil inlet and outlet flow of the clutch stroke actuator chamber (single action).
The maximum flow rate is 10l/min with pressure differential of 10 bar. The control current ranges from 0 to 2A directly controlled by control unit CFC 208F. Electrical resistance of the winding is 2.5 Ohm +/- 6% at 20°C.

Solenoid valve position and flow rate/current diagram

Solenoid valve position and flow rate/current diagram

 Posted by at 4:15 pm
Jun 062013
 

This is one of the system components where the actuators, position sensors, actuator solenoid valves have been incorporated, specifically connected by cables that link them to a centralised multiple connector.
This solution simplifies and cuts down assembly time on the gearbox and avoids connection errors. Furthermore the actuator solenoid valve cables all have identification labels.

Electro-Hydraulic Group 1

Electro-Hydraulic Group 1


Electro-Hydraulic Group 2

Electro-Hydraulic Group 2

Description

  1. A casting casing fastened on the gearbox
  2. Single action actuator to activate the clutch lever
  3. Proportional pressure solenoid valve EV1 to control the engagement of the odd gears 1-3-5
  4. Proportional pressure solenoid valve EV2 to control the engagement of the even gears 2-4-R
  5. On-off solenoid valve EV4 to control 5-R gear selection
  6. On-off solenoid valve EV3 to control 1-2 gear selection
  7. Proportional flow-rate solenoid valve EV0 to control the clutch actuator
  8. Hydraulic gas accumulator
  9. Hydraulic circuit pressure sensor
  10. Sensor to detect clutch actuator position
  11. Sensor to detect engagement actuator position
  12. Sensor to detect selector actuator position
  13. Bleed valve
  14. Access to gear shaft actuators connecting screw
  15. Union for oil delivery pipe
  16. Union for oil return pipe
  17. Connector for gearbox speed sensor
  18. Selespeed wiring harness connector

The following are also installed in the electro-hydraulic group:

  • A check valve
  • An oil inlet filter
  • Screws fastening the engagement / selection actuator to the gearbox gear shaft.
 Posted by at 3:27 pm
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

Description

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

Hydraulic System – Diagram

Hydraulic diagram

Hydraulic diagram

Description

  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

Description

  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