1. Windscreen Wash / Wipe Systems
Topics covered in this presentation:
Front and Rear Wiper Systems
Washer Systems and Components
Self Park and Automatic Speed Adjust Systems

2. The Wiper System
Windscreen wipers are designed to keep the windscreen clear. They remove substances such as water, ice, mud and snow.
Windscreen
Wiper arm and blade
The wiper system consists of wiper arms and blades, an electric (wiper) motor and mechanical linkages.
The wiper arms are moved by the wiper motor, via the linkage mechanism.
Linkages
Wiper motor
The wiper system is robustly made and very reliable. The rubber wiper blades are the only consumables.
Reservoir

3. The Wiper Motor The wipers are driven by permanent magnet DC motors.
Rotating arm
Gears
Rubber grommet
The wipers are driven by permanent magnet DC motors.
The end of the motor shaft is fitted with a worm gear that drives a series of output gears (compound gear train) to achieve a high torque ratio.
The motor and gears are incased in a metal or plastic case, with hard packed lubricating grease for smooth lengthy running.
Rubber grommets fix the motor to the vehicle chassis to prevent vibrations and noise.

4. The Wiper Arm and Blade
The arm of a windscreen wiper is made from a long thin piece of robust metal. It is shaped to be structurally strong and narrow, so as not to obstruct a driver’s view.
Arm
A spring at the base of the arm, helps to keep the wiper pressed against the windscreen.
Wiper blade
The wiper blade consists of a metal support and a soft flexible rubber blade element. The rubber blade element wipes the windscreen surface clean.
Element
The rubber blade element must be periodically checked for wear damage. Blades are relatively cheap and easy to replace.

5. Wiper Linkage
Rotating arm
The wiper linkage connects the wiper motor to the wiper arms. The motor moves the linkage, which moves the wipers in the correct manner.
Linkage
Wiper motor
Wiper arm
A flexible rack type uses a pliable worm gear in conjunction with a cam to move the wiper arms.
In a link type system wiper, movement is achieved through a cam and levers.

6. Washer System
The washer system forces water onto the windscreen. This aids the wiper blade, as it clears material from the surface of the windscreen.
Water (plus screen wash) is pumped from a reservoir onto the windscreen, through flexible hoses and small jets.
The jets can be adjusted to vary the spray angle.
Reservoir
Washer pump
Flexible hose
Jet

7. Washer Pump
The washer pump motor may be internally, or externally mounted.
Brushes
Armature
From
reservoir
It contains an impeller that produces a centrifugal force, which pressurizes the system.
Magnets
Water is forced from the reservoir to the windscreen.
Oil
Impeller
To jet
A reciprocating pump was used on early vehicles. This was activated by a pedal on the floor.
From reservoir
To jet

8. Rear Washer and Wiper
Some vehicles incorporate a rear washer / wiper system to provide a clear, rear, view.
Reservoir
Pipe
The mechanical arrangement of this system is very similar to that used on the front windscreen.
The washer system either shares the front reservoir with a pipe running through the roof, or it has its own separate reservoir.
Wiper

9. Self Park Switch Schematic
The self park switch is a system that ensures the wipers come to rest, at the bottom of the windscreen. The driver’s view must not be obstructed.
When the wipers are switched on, the wiper motor and the drive gear rotate. The park switch is closed, except when it is opened by the cam.
Drive gear
When the wipers are switched off, the park switch provides voltage to the wiper motor, until it is opened by the cam. The cam stops the wipers in the correct place.
Self park cam
Wiper motor
Park switch
Wiper on/off switch
Battery

10. Automatic Rain Sensor
Some wiper systems use infrared sensors to detect refracted light, as rain falls. The signal from the sensors is sent to a control module that controls wiper speed.
In adverse weather conditions, the module automatically adjusts wiper speed. A manual override switch is provided with these systems, to allow for driver control.