Jun 062013
 

Gear selection control lever

The lever has only one stable position (A) and 4 unstable (+, -, N, R).

Gear selection lever

Gear selection lever

It has four normally open switches, each with two electric resistors (one in parallel at contact, the other in series). To go to a higher gear, push the lever toward (+), to have a lower gear, push toward (-). To insert idle (N) move the control lever to the right Reverse gear (R) can be engaged from any gear, moving the gear lever to the right then back, with the vehicle stationary and the brake pedal pressed.

Gear selection lever electrical connection

Gear selection lever electrical connection

 Posted by at 4:32 pm
Jun 062013
 

Hydraulic circuit oil pressure sensor

It is installed directly on the hydraulic group.

Position of oil pressure sensor

Position of oil pressure sensor

It is installed directly on the hydraulic group. It consists of a capacitive sensitive element that generates a signal processed by a specific custom circuit inside the metal casing. It supplies the control unit CFC 208F with a voltage proportional to the pressure read, with reference to the supply voltage of the sensor. The supply voltage from CFC 208F is 5+/-0.5V with a draw of approx. 10 mA. The maximum pressure value read is approx. 80 bar.

Pressure sensor diagram

Pressure sensor diagram

Actuators position sensor

Actuators position sensor

Actuators position sensor

The sensors that send the position of the gear selection, gear engagement and clutch control actuators to the Selespeed control unit are single ramp potentiometers installed directly on the electro-hydraulic group. They are powered with 5V+/-0.5V by the control unit CFC 208F. Maximum resistance between pins A-B is 1200 +/- 20Ohmat 20°C.

Location of actuator position sensors

Location of actuator position sensors

The three sensors, of the same type, installed on the electro-hydraulic group are:

  1. Gear selection position sensor
  2. Gear engagement position sensor
  3. Clutch position sensor

Clutch disk speed sensor (gearbox primary)

This is installed on the gearbox inlet, directly on the gear box.
It is an electromagnetic sensor and sends a sinusoidal signal to the control unit CFC 208F that has a frequency in proportion to the speed of a pinion mounted on the gearbox primary shaft. The winding resistance is 1200 Ohm +/- 10% at 20°C. The air gap ranges between 0.2-1 mm.

Gearbox speed sensor position

Gearbox speed sensor position

Switch on brake pedal

Installed on the brake pedal unit.

Brake pedal switch

Brake pedal switch

When the pedal is released it does not send any signal (NC) to the control unit CFC 208F. When the brake pedal is pressed the BRAKE lights switch on and the switch sends the car braked signal (12V) to control unit CFC 208F.

Door open switch

This reads the information (ON-OFF) regarding the state of the driver side door, sending an earth signal to the control unit CFC 208F when the door is open.

 Posted by at 4:30 pm
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