The fully automatic convertible top is a folding top fitted as an option.
The soft top is opened and closed hydraulically. When closed, the soft top is locked on the window frame via catches. The catches are driven by means of an electric drive. After opening, the soft top is stored in the convertible top compartment and locked in place by the catches.
The convertible top module (CVM IV) controls and monitors the hydraulic and electrical drive and locking components of the folding top. The convertible top module also monitors the convertible top switch, the hydraulic pump and the locking drive, and saves any faults that occur in the fault memory.
The soft-top module is connected to the K bus.
The power windows are contolled during soft-top operation by the general module of the central body electronics (ZKE). The general module therefore receives the information 'Open/close top' or 'Top complete closed' or 'Complete open' across the K bus.
The instrument cluster provides the convertible top module IV (CVM IV) via the K bus with the information 'Outside temperature' and ”Vehicle moving” or ”Vehicle stationary” (speed greater than/less than 4 km/h).
Exchange of information is across the K bus.
The hydraulic unit creates the hydraulic pressure required for the top movement. The hydraulic unit consists of an oil reservoir that has an integrated pressure pump. All the hydraulic valves are integrated in the hydraulic unit. The hydraulic system is a closed, self-venting system. Topping up hydraulic fluid is not required.
The pressure pump is driven by a reversible DC motor. To change the direction of movement of the folding top, the direction of rotation of the pump motor is switched.
The pump ony operates in the case of top movements. To prevent damage, the hydraulic unit is monitored by an integrated temperature sensor. At a temperature of 105°C, the pump in the hydraulic system is switched off. The soft top can then only be moved by hand.
The soft top is moved in two directions by dual-action hydraulic rotary drives for opening and closing. Here, the racks of the hydraulic cylinder engage in pinions that convert the longitudinal movement of the hydraulic cylinder into a rotary motion. The pinions transfer the rotary motion across the main bearings to the convertible top frame. The hydraulic rotary drives are fitted on the left and right in the main pillar on the main bearings of the convertible top frame.
For the soft-top locking mechanism, there are two catches which are opened or closed by an electric motor.
When closed, the soft top is locked on the window frame (cowl panel) via catches.
After placing in the convertible top compartment, the soft top is also locked in place by the catches.
In the event of an electrical function failing, emergency release is possible by hand.
The convertible top switches are fitted in the switching centre in the centre console. There are separate switches for opning and closing the soft top.
For the display of the active and/or receding state, red and yellow LEDs are fitted beside the convertible top switch:
The red LED lights up while the top is moving. When one of the final positions is reached (top stored in the convertible top compartment or locked on the cowl panel), it is switched off. The LED flashes when the convertible top switch is released while the top is not in one of the two final positions.
The yellow LED lights up when the convertible top switch or the convenience function sends a request for opening while the convertible top compartment floor is not down.
In order to detect the convertible top position and the two final positions of the locking mechanism, non-contact switches (Hall sensors) are used. The Hall sensors for identification of the convertible top position are fitted on the right-hand main convertible top bearing. The Hall sensors for the cowl panel lock are located on the cowl panel lock in the front convertible top bow strut. The information from the Hall sensors is processed in the convertible top module IV (CVM IV).
The convertible top compartment switch is an earth-switching contact that generates the signal ”Floor down” when the convertible top compartment floor is located in the lowest position. As long as this information is not present, the soft top cannot be unlocked and opened.
The convertible top compartment floor switch is fitted on the folding mechanism of the convertible top compartment floor.
Contact plates are fitted in each of the two hardtop locating points at the main convertible top bearings. Each contact plate has a contact for power supply of the rear window heating and a contact for hardtop detection.
It is possible to open / close the convertible top by means of:
The following conditions must be met at one time for automatic movement of the top:
Pressing the convertible top switch for ”Open top” opens the soft top according to the following sequence:
Pressing the convertible top switch for ”Close top” closes the soft top according to the following sequence:
NOTE: If the convertible top switch is released during closing and opening, the movement and locking of the folding top is interrupted immediately. As there is no blocking of the drive, only the self-regulation system of the mechanical system and the hydraulic rotary drive have an effect. Pressing the convertible top switch again restarts the stopped movement.
The driver's door lock opens or closes the top in the following sequence:
As long as the soft top is locked and terminal R is on, the convertible top module IV (CVM IV) provides a signal for control of the rear window heating.
Power supply for the rear window heating of the soft top comes from the convertible top wiring harness. If the hardtop is fitted, the power supply for the rear window heating is by means of contact plates on the rear hardtop locating points.
If a hardtop is fitted, a contact that closes to earth generates the signal ”V_SPERR” which blocks the ”Close” function.
To release: On completion of an opening procedure, the soft top is stored in the convertible top compartment and locked in place. As interlock, the central locking lug of the cowl panel lock engages in the retainer on the convertible top compartment.
To close: At the start of a closing operation, the cowl panel lock is operated first. Here, the centre locking lug of the cowl panel lock is moved in. This disengages the mechanical interlock.
Locking and unlocking the folding top on the cowl panel (upper window frame) takes place electromechanically with the cowl panel lock in the front convertible top bow strut. To this end, there are locking hooks on the left and right of the cowl panel lock.
For closing the folding top, the locking hooks are closed and locked after entering the cowl panel.
The rotary motion of the spindles of the cowl panel lock required for opening and closing is generated by a direct current motor with angle gear. The direct current motor with angle gear is located in the centre of the front convertible top bow strut. The rotary motion is transferred via flexible shafts.
In the event of failure of electrical and/or hydraulic functions, the top can be opened and closed using emergency unlocking/locking systems.
Emergency closing:
Emergency opening: