Principle of Operation
Principle of Operation
Operating the Windows
The power windows are enabled and disabled by the power-window master in the CAS. Enabling and disabling are dependent on coding and the status of the door contacts and the terminal status.
The power windows can be operated from "terminal R on" and are disabled in the crossover into "sleep mode".
The switch control logic, which was introduced for the first time in the E46, is also used in the E65/E66. This prevents the windows from being closed by mistake.
Toll operation (one-touch) takes place in the closing or opening direction immediately after the switch position "one touch closed" or "one-touch open" has been reached. The power windows are activated in the initial closed/open lock-in positions as long as the button is held in this position. Anti-trapping protection is active in both one-touch and manual operation.
The function with the highest priority that is started or selected first is executed. However, a one-touch function can be cancelled by the local switch.
In order to prevent damage to the motor, the window travel is subject to a maximum activation time of 10 s (exception: initialization run).
If the window glass moves to the upper stop, the drive is activated at full power for the blocking time of 0.5 s in order to ensure safe closing.
The following functions are available thanks to timed activation of the power-window drives by means of power final stages:
- Smooth start-up
- Smooth rundown
- Speed control (2 speed stages)
Emergency Close
This function is used for deliberate closing of the windows without anti-trapping protection. Use of this function may be necessary for example in the event of an attack from an outside source or closing a window glass which has frozen solid.
The entire control sequence is divided into two phases:
Phase 1:
The emergency-close mode is activated after 0.5 s when the position "one-touch closed" is held. The window is closed at maximum speed and with modified anti-trapping protection. Releasing the button terminates emergency closing,(i.e. the window proceeds to be closed with full anti-trapping protection as with automatic operation).
Anti-trapping protection remains activated in modified form even during emergency closing. If trapping is detected, the window travels back only the short distance of 20 mm, This relieves strain on the mechanical system or gives the attacker the option of backing away.
Phase 2:
The button must now be released ("zero position") and then pressed again in the position "overpressed closed" within 4 s.The window is now closed without anti-trapping protection with full force. In the event of blocking, the window is powered until the motor thermal protection is activated or the window has moved to the upper stop.
Emergency closing is terminated when the button is released. For safety reasons, it is always possible to open the window independently of the thermal protection.
If there is no renewed activation of the emergency-close mode within 4 s(overpressing and holding), anti-trapping protection returns to its normal state."Emergency close" is not operational from a vehicle speed of >16 km/h (10mph).
When the child lock is engaged, the emergency-close function cannot be activated by the local switches in the rear doors but only only by the switch block in the driver's door.
An emergency-closing operation activated by the switch block in the driver's door cannot be interrupted by the local buttons in the front passenger door or the rear doors.
The emergency-close function can be completely deactivated by means of coding.
Convenience 0pening/Closing
The convenience function enables the operator to close or open all the windows and the slide/'tilt sunroof before entering or leaving the vehicle.
The convenience opening function can be triggered by means of the Remote Control key. Both convenience opening and closing can be operated by mechanical key operation in the driver's door lock.
The function is controlled by the power-window master in the CAS control unit. For this purpose, a K-CAN-P message is sent from the CAS to the four doors.
Closing
The closing operation starts after a delay; for this purpose, the key must be held in the locking (VR) or double locking (ZS) position during the entire closing operation. The closing operation can be terminated at any time by turning the key back. The sequence begins again after 0.5 s if a ZS command is entered again within 3 s of the cancellation.
The individual windows and the sunroof are closed in the following sequence: rear power windows (PWs), front PWs and sunroof. The PWs are activated so that two PWs are always switched on simultaneously (starting with the rear). The front PWs are started after a 1 s delay. The sunroof is closed immediately when all 4 windows are closed or 3.5 s after the start of convenience closing.
Opening
In the unlocking lock cylinder position (ER), it is possible to initiate convenience opening by holding the key in this position. With convenience opening, first the front PWs are opened, followed by the rear PWs after a delay of 1 s. The sunroof is opened immediately when all 4 windows are open or 3.5 s after the start of convenience opening.
The operation can be terminated at any time by turning the key back. The sequence begins again after 0.5 s if an ER command is entered again within 3 s of the cancellation.
Operation by Remote Control is performed in the same way as operation by lock cylinder.
Child Lock-out
Operation of the two rear power-window buttons is disabled by means of the child-lock button in the switch block in the driver's door. When the child lock is engaged, it is only possible to operate the rear power windows from the driver's switch block or via the convenience function. An LED in the button indicates the current status of the child lock.
The LED is activated by the power-window master in the CAS. No opening/closing function is triggered when the child lock is engaged.
In the event of a fault, the Check Control message "Child lock not functioning" in the instrument cluster is sent by the CAS.
It is only possible to deactivate the child lock in conjunction with a valid Remote Control in the ignition.
The child lock remains engaged after a CRASH telegram has been received.
Motor Protection (thermal protection)
Each power-window motor is provided with its own thermal protection to prevent them from overheating. For this purpose, the motor running time is added up in a counter. The output value of the counter is influenced by the ambient temperature.
If the counter exceeds a threshold, new control requests are no longer accepted but a movement that is already in process is continued. The counter is reduced again if the motor is deactivated. Operator prompts are accepted again when the value drops below the threshold. Return window travel in the event of trapping is not obstructed by the thermal protection.
Load Deactivation
In order to assist starting, the power windows are not operational with terminal 50 (starter motor). Each action, e.g. opening or one-touch function, is terminated immediately and the power windows are stopped. Following the starting sequence, the windows are fully operational again once they have been re-actuated.
Undervoltage Deactivation
The supply voltage is monitored locally in the doormodules. If the supply voltage is below 9V, the power windows are disabled.
Smooth Start-up
Smooth start-up describes a new feature of the E65/E66 which starts the power windows with a linear increase in speed up to full speed. Smooth start-up takes place in both the closing and opening directions.
Clunking noises are avoided in the door due to the low speed as play in the window lift assembly is taken up.
To ensure that the windows remain quiet during the entire service life of the vehicle, the gradient of the first ramp is less steep than that of the second ramp. The total window travel until the full desired speed is reached is approx.5 mm.
Smooth Rundown
Smooth rundown describes running down of the power windows with a linear decrease in the infinitely variable speed until the window is at a standstill. This function is used when approaching the end positions (in both automatic and manual operation) of the lower and upper stops.
The smooth-rundown travel is about 15 mm on the downward travel and about 30 mm on the upward travel.
Synchronous Motor Operation
The window speed is kept constant over a wide voltage range by timed activation (PWM) of the power windows.
Blocking Protection
Blocking protection is based on monitoring of the Hall-sensor signals. With each signal change of the active sensor, a time measurement is restarted which triggers the blocking reaction when a defined period of time is exceeded (exception: emergency close).
If blocking protection takes place in an adjustment range protected by closing-force limitation, the window travels back when the closing-force limitation is exceeded. Outside this range, the window travels back for 1/4 turn in order to relieve the tension on the mechanical system,
Anti-Trapping Protection
Anti-trapping protection restricts window closing force to a maximum permissible value (closing-force limitation). Any load in excess of this force causes the window to immediately stop and reverse.
The power windows require an initialization procedure during the initial start-up.
The initialization procedure consists of:
- Standardization
- Learning of characteristic closing-force curve
When the window is standardized, the end positions of the window travel are determined by a blocking run in the upper window seal and on the lower window stop. When the closing force is being learned, it is measured over the entire closing travel and permanently stored.
Anti-trapping protection is active and one-touch closing is possible only after initialization has been completed.
Calibration of the triggering threshold begins with a closing force of approx.500 N. This high starting value increases operational reliability so that the windows are closed even in the event of stiffness.
Manual Initialization
The power-window system must always be initialized after any repair work affecting the system has been carried out.
Operation sequence:
- Press the power window switch in the open direction for at least 15 s but no longer than 25 s.
- Release the switch and then pull it to the "one-touch" close position and hold it. Initialization begins (this step is part of the CAS logic to prevent a trigger of the initialization mode if the switch is jammed).
- Hold the switch in the "one-touch" close position until initialization is completed. The windows will open and then return to the closed position to confirm a successful initialization.
- A Check Control message is issued if any of the side-windows are not initialized. The message is retracted as soon as all windows are successfully initialized.