Windscreen wiper is a device employed to keep the windscreen clean during rain, snow, etc to ensure good visibility
A wiper generally consists of an arm, pivoting at one end and with a long rubber blade attached to the other. The blade is swung back and forth over the glass, pushing water from its surface. The speed is normally adjustable, with several continuous speeds and often one or more "intermittent" settings. Most automobiles use two synchronized radial type arms, while many commercial vehicles use one or more pantograph arms. Mercedes-Benz pioneered a system called the Monoblade in which a single wiper extends outward to get closer to the top corners, and pulls in at the ends and middle of the stroke, sweeping out a somewhat 'W'-shaped path.
Some larger cars are equipped with "hidden" (or "depressed-park") wipers. When wipers are switched off, a "parking" mechanism or circuit moves the wipers to the lower extreme of the wiped area, near the bottom of the windscreen, but still in sight. To hide the wipers, the windscreen extends below the rear edge of the hood, and the wipers park themselves below the wiping range at the bottom of the windscreen, but out of sight.
Wipers may be powered by a variety of means, although most in existence today are powered by an electric motor through a series of mechanical components, typically two 4-bar linkages in series or parallel. Vehicles with air operated brakes sometimes use air operated wipers, run by bleeding a small amount of air pressure from the brake system to a small air operated motor mounted just above the windscreen. These wipers are activated by opening a valve which allows pressurized air to enter the motor.
Early wipers were often driven by a vacuum motor powered by manifold vacuum. This had the drawback that manifold vacuum alters depending on throttle position and is almost non-existent under wide-open throttle; the wipers would slow down or even stop. This problem was overcome somewhat by using a combined fuel/vacuum booster pump. Some cars, mostly from the 1960s and 1970s, had hydraulically driven . On the earlier Citroën 2CV, the windscreen wipers were powered by a purely mechanical system: a cable connected to the transmission, to reduce cost this cable also powered the speedometer. The wipers' speed was therefore variable with car speed. When the car was waiting at a crossroad, the wipers were not powered, thus a handle under the speedometer allowed the driver to power them by hand.
FIG 1.2 WIPER ATTACHED TO A VEHICLE
Most windscreen wipers operate together with a windscreen (or windshield) washer; a pump that supplies water and detergent (usually a blend called windscreen wiper fluid) from a tank to the windscreen through small nozzles, mounted on the hood or on the wipers, known as a 'wet-arm' system. In warmer climates, water may also work, but it can freeze in colder climates. Although automobile antifreeze is chemically similar to windscreen wiper fluid, it must not be used because it can damage paint.
Some vehicles have small wipers or washers on the headlights. In more modern vehicles, these have been replaced with a powerful jet spray, without wipers. Some vehicles are fitted with wipers (with or without washers) on the back window as well. Rear-window wipers are typically found on hatchbacks, station wagons, sport utility vehicles, minivans, and some sports cars. They were first implemented in the 1970s, but SUVs did not use them until the 1980s. Vehicles are now available with intelligent (automatic) windscreen wipers that detect the presence and amount of rain using a rain sensor. The sensor automatically adjusts the speed of the blades according to the amount of rain detected
AN AUTOMOBILE IS A WHEELED VEHICLE CARRYING ITS ON MOTIVE POWER UNIT.
World’s first three-wheeled automobile with Otto cycle petrol engine was built by Karl Benz of Germany in 1885 and was granted patent on 29 January 1886.At the same time another team from Germany Gattlieb Daimler and Wilhelm Maybach built and patented the first motor cycle.
Soon thereafter, Benz also invented accelerator for speed regulation, battery ignitionsystem, sparkplug, clutch, gear shift and the radiator for cooling of the engine, with these improvements he started with production of the automobile first in the world in the year 1888.however it was in the year 1893 that the first four wheeled automobile was introduced by him. This was fitted with four stroke engine of his own design.
Almost Concurrently, Daimler and Maybach also produced about thirty vehicles during 1890 to 1895 at the Daimler works and the hotel Hermann.
All round development in the fields of design and manufacture of automobiles has resulted in vast improvements in their efficiency, comfort and safety, with consequential tremendous increase in their use world wide. Whereas Benz produced only 25 vehicles and Daimler-Maybach made almost 30 vehicles in first five years of their production, 63million cars and light trucks were produced worldwide in the year 2005.
2.1 NEED FOR AUTOMATION:
Automation can be achieved through computers, hydraulics, pneumatics, robotics, etc., of these sources, pneumatics form an attractive medium for low cost automation. Automation plays an important role in automobile.
Nowadays almost all the automobile vehicle is being atomized in order to product the human being. The automobile vehicle is being atomized for the following reasons.
Ø To reduce man power
Ø To increase the efficiency of the vehicle
Ø To reduce the work load
Ø To reduce the vehicle accident
Ø To reduce the fatigue of workers
Ø To high responsibility
Ø Less Maintenance cost
Ø To achieve high safety
The major components of the “Automatic rain operated wiper” are
· Conductive Sensor
· Wiper Motor and its arrangement
The aim is to design and develop a control system based an electronically controlled automotive rain operated motor is called “AUTOMATIC RAIN OPERATED WIPER”
Rain operated motor is consists of conduction sensor (Tough sensor) circuit, Control Unit, wiper motor. The sensor is used to detect the rain or water flow. There is any rain on the class, the sensor senses the rain or flow water and giving the control signal to the wiper motor.
We have pleasure in introducing our new project “AUTOMATIC RAIN OPERATED WIPER”, which is fully equipped by sensors circuit and wiper motor. It is a genuine project which is fully equipped and designed for Automobile vehicles. This forms an integral part of best quality.
Windscreen wipers are operated by means of a small motor though some manufactures use compressed air for this purpose.the motor driven from the worm which rotates the wheel a link connects the wheel with the toothed sector.as wheel rotates the sector reciprocates about fulcrumthis motion is then imparted to the similar sector on the spindle on which is mounted the wiper arm.wiper blade is attached to the wiper arm by means of a spring lock.a rubber wiping elememt is heldin place in the wiper blade.The battery supplies the power to the sensor as well as rain operated motor. Wiper motor is automatically ON during the time of rainfall. The senor is fixed in the vehicle glass. The conductive (Touch) sensor is used in this project. It senses the rainfall and giving control signal to the control unit. The control unit activates the wiper motor automatically. This operation is called “Automatic rain operated wiper”.
An automatic windshield wiper system connected to a source of power and windshield wipers of a vehicle for automatically controlling operation of the windshield wipers based upon an intensity of falling precipitation. The automatic windshield wiper system includes a transducer for sensing precipitation and generating a signal indicative of the sensed precipitation and a comparator connected to receive the control signal. The comparator analyzes the control signal to determine whether precipitation is falling. A relay is connected between the comparator and the windshield wipers. The relay is toggled by the comparator to supply power from the power source to activate the windshield wipers upon a determination by the comparator that the transducer sensed falling precipitation, the transducer continually senses the state of falling precipitation and continually transmits signals to the comparator. The comparator toggles the relay between the open and closed states turning the windshield wipers on and off based upon the conditions sensed by the transducer.
Fig4.1 BLOCK DIAGRAM
This is the block diagram (Fig4.1) showing the details of the automatically operated sensors. In this the touch sensor is attached on the glass frame and the connection is given to the control unit. A battery is connected to the sensor circuit. The connection is then given to the wiper motor .the wiper is integrated in the wiper motor device so when the motor works the wiper also starts actuating.
Fig4.2 WATER SENSOR
Rated voltage DC 5.0V
Rated power <=3.0mA
Operating temperature 0-60C
Operating humidity 30-90%RH
Storage humidity Within 95%RH
Storage temperature 30-85C
Standard output DC 1,980(at 25C 60%RH)
Accuracy +-5%RH(at25C, 60%RH)
Remarks PCB unit containing thermistor or diode for temperature compensation
Fig4.2 CHARASTERISTICS CURVE
Fig4.4 SENSOR DIMENSIONS
Fig4.5 CIRCUIT DIAGRAM
This is the circuit diagram (Fig4.5) detailing the working principle of the touch sensor. This sensor is attached to the wiper motor and makes the wiper motor automatically turn on and turn off in according to the given inputs.
Automatic rain operated wiper is commonly used in the vehicles in European countries.The system is mainly used in this region because of the climatic conditions.
The vehicles in which this systems are used is
Ø VW Sharan,
Ø Honda Civic,
Ø Subaru XT,
Ø Mercedes-Benz W124 (with cantilevers to reach into corners of screen),
Ø US Military Wheeled Vehicles,
Automatic rain operated wipers are not common in India and too not affordable for a middle class car manufactures to accommodate this mechanism in their low cost vehicles. The unavailability of the specific parts for this mechanism also makes the automatic wipers a dream from low-cost vehicles in India.The cost analysis can not be done with comparatance because of the unavailability of mechanism here.
The actual cost of the standard mechanism using in luxury cars goes above 10,000rs excluding the wiper mechanism.
We have done the project with a cost below1000rs.this is not a standard part but works as do the standard parts do.
· Low cost automation project.
· Free from wear adjustment.
· Less power consumption
· Operating Principle is very easy.
· Installation is simplified very much.
· To avoid other burnable interactions viz.… (Diaphragm) is not used.
· It is possible to operate Manually/automatically by providing On/Off switch.
· Sensor cost is very low due to conductive sensor
· This system applied in the case of water falling on the sensor only.
· Addition cost is required to install this system to four wheeler.
Most of the vehicle manufactures now emerging in the industries are concerned about the facilities that offering to the customers. To make it functional and efficient the manufactures comes with new ideas and technologies. one of such innovative move is the automatic rain operated wiper. This comes with a new experience to the customers. In our project a automatic rain operated system is studied, fabricated and demonstrated. we hope the Indian manufactures also fulfill the dreams of Indian automobile oners.