Front Wiper Systems
Front Wiper System
In order to maintain optimal conditions for effective wiping the design phase took into account the relationship between the windshield geometry and the wiper system. Specially-shaped unarticulated Aero wiper blades, which lie flatter against the wind- shield than conventional systems, are being used for the first time by Porsche. This means that the direction reversal of this system is not performed by a mechanical drive, but rather by the negative phase of an electronic motor. The terminal voltage of the motor is reversed in the return position.
The passenger-side wiper is designed with a so-called controlled wiper lever to provide a broader cleared field of view. The wiper motion is performed by a four-joint kinematic at the base of the wiper arm.
The front wiper system has two speeds as well as an intermittent setting. The speed is set using three settings on the right steering column lever. Hall sensors are used to detect wiper position and wiper motor rotation in order to control wiper speed.
Inside the interior mirror base is the rain sensor (standard), which controls the wiper interval. The wiper interval can be customized or adjusted using a potentiometer in the right steering column lever.
When operating in rain sensor mode, the wiper speed is infinitely variable as needed.
In order to optimize aerodynamics while minimizing wind noise, the wiper arms are parked out of the line of sight (beneath upper lip of the hood).
The system consists of a reversible, RPM-regulated 2-brush wiper motor with integrated electronics in the drive cover and wiper arm with blade.
The wiper module communicates with other control modules via CAN-interface. The rain sensor is connected to the wiper control module using a serial interface.
Individual Functions
Intelligent, Staged Stall and Thermal Protection
An intelligent stall and thermal protection system was installed to avoid damage to the wiper module caused by heavy snow, freezing or other blockage of the wiper. The stall protection function monitors motor speed as well as other set variables.
If, for example, there is a lot of snow on the windshield, the wiper motor electronics adapt the wiped area to the conditions of the windshield.
In this way the return points of the wiper motion are set lower in order to provide the widest possible cleared field of view.
Function
In the event of excess power consumption by the wiper motor, over load protection is provided by thermal performance data in the software, which lowers power consumption by reducing the wiping frequency or by introducing short pauses in the interval. The thermal performance data includes motor and control module temperature measured in the control module as well as exterior temperature(via CAN). Blockage is identified by standstill of the rotor and maximum motor terminal voltage. After several attempts, the wiper motor is switched off. This lockout can be cancelled by switching the ignition off and on, or by operating the wiper switch again.
Voltage Monitoring
The control module monitors the voltage supply. If the voltage exceeds the specified range (9V to 15V) wiper motion is stopped: once the voltage returns to the permissible range, the desired operation mode resumes.
- When the engine is started, the wiper motor is likewise briefly halted.
Continuous Wiping Stage 1 and Stage 2
Selection on the wiper switch (Stage 1/Stage 2) is read as a signal by the switch module and transmitted to the wiper control module via CAN. This, in turn, operates the wiper motor at the desired speed.
Rain Sensor and Intermittent Settings
The rain sensor on vehicles so equipped measures precipitation on the windshield, including snow. Correspondingly, the wiper speed/frequency is automatically set between intermittent to continuous (Stage 1 and Stage 2). The rain sensor function supercedes the interval function.
The following will activate the rain sensor:
- Setting the wiper lever from Neutral to Stage 1
- Operating the windshield washer system
- Changing the rain sensor sensitivity with the thumb wheel
Activation of the rain sensor is confirmed by a single wipe of the blade.
Function
Increasing the sensitivity by the potentiometer on the wiper switch triggers a single wipe cycle, thus transmitting information to the rain sensor via the serial interface, During the pauses in wiping, the wiper is placed into a raised "Interval Parking" position and is protected against backlash by the motor.
Activation of the intermittent operation immediately results in a full wipe cycle. This does not occur, however, if the intermittent function was active before the ignition was switched on. If the rain sensor does not receive a signal after a specified period, the intermittent operation starts with one wiping cycle. The interval pause is determined by the wiper set point, vehicle speed and potentiometer value.
The wiping speed during intermittent operation corresponds roughly to Stage 1. Shortening the interval pause on the potentiometer triggers a single Niping cycle.
Automatic Reduction of the Wiping Frequency
This function is activated after the ignition is switched on (Terminal 15) and the vehicle achieves a speed of > 5 mph (8 km/h). If Stage 2 has been selected and the vehicle speed is greater than 5 mph (8 km/h), the wiper operates at Stage 2.
If the speed goes below 2.5 mph (4 km/h) the wiper speed switches from stage 2 to Stage 1.
If the vehicle speed increases again to > 5 mph (8km/h), the wiper, Depending upon the lever setting, will run at Stage 2.
If Stage 1 has been selected, the wiper speed is set to Intermittent is the vehicle speed is 2.5 mph (4 km/h). The interval pause period is 4 seconds. If the vehicle speed returns to above 5 mph (8 km/h) the wiper again operates at Stage
Automatic decrease of wiper speed is interrupted by a function modification on the circuit. The automatic decrease in wiper frequency resumes after the vehicle speed reduces from > 5 mph (8 km/h) to below 2.5 mph (4 km/h).
Wiper Position Reference Point
A sensor on the rotor of the wiper motor supplies data for the wiper position. The wiper control requires a reference point in order to determine an absolute position from this value. After the ignition is switched on (Terminal 15), the wiper is moved in the downward direction until the reference point is found.
One Tap Wipe
Pushing the wiper lever downward activates a single wipe cycle of three intervals. If the switch is held down longer, the wiper motor increases from Stage 1 to Stage 2 after the next sweep of the wiper. The wiper operates at Stage 2 as long as the touch wipe function is maintained. When the lever is released, the wiper blades are parked.