Window and lens glass cleaning system for a motor vehicle

A window and lens glass cleaning system for a motor vehicle has a constructional unit comprising a washer fluid container (1), a plurality of control units (7-9) and an evaluating device (12) of a fluid-level sensor (12a). This enables all of the essential components of the window and lens glass cleaning system to be preassembled and tested outside the motor vehicle. The window and lens glass cleaning system can then be installed in a particularly simple manner in the motor vehicle.

FIELD AND BACKGROUND OF THE INVENTION
 The invention relates to a window and lens glass cleaning system for a
 motor vehicle, having a washer fluid container for storing washer fluid,
 having at least one washer fluid pump which is arranged on or in the
 washer fluid container, for conveying washer fluid from the washer fluid
 container to washer nozzles to be arranged in front of motor vehicle
 windows and lenses, and having an electronic control unit for activating
 the washer fluid pump or the washer fluid pumps.
 Such window and lens glass cleaning systems are frequently used in modern
 motor vehicles and are known from practical experience. In this case, the
 washer fluid container contains a washer fluid pump in each case for a
 windshield, a rear window and for headlight lenses of the motor vehicle.
 The washer fluid pumps can be activated independently of one another by
 operating elements arranged within the passenger cell of the motor
 vehicle. The electronic control unit is fastened at a splashproof location
 in the motor vehicle. Signal lines are routed from the control unit to the
 operating elements and supply lines for electric power are routed to the
 washer fluid pumps and to the motor vehicle electric network.
 A disadvantageous feature in the known window and lens glass cleaning
 system is that its installation in the motor vehicle turns out to be very
 complicated. Furthermore, the window and lens glass cleaning system has
 first of all to be put together before it is installed in the motor
 vehicle for preliminary testing and then has to be taken apart again. A
 very great number of working steps are required for this.
 SUMMARY OF THE INVENTION
 The invention is based on the problem of providing a window and lens glass
 cleaning system of the type mentioned at the beginning in such a manner
 that it can be installed in as simple a manner as possible in the motor
 vehicle and can be tested in a very simple manner before it is installed
 in the motor vehicle.
 According to the invention, this problem is solved by the control unit and
 the washer fluid container being formed as a constructional unit which can
 be preassembled.
 This enables all of the electrical components of the window and lens glass
 cleaning system according to the invention to be preassembled and tested
 outside the motor vehicle. The invention means that after the testing
 there is no longer any need to separate the electronic control unit from
 the washer fluid container, since the constructional unit can be installed
 in a single operation. This makes the installation in the motor vehicle of
 the window and glass lens cleaning system according to the invention very
 simple. A further advantage of the window and lens glass cleaning system
 according to the invention is that the supply lines can be designed such
 that they are very short. Since the washer fluid pumps require starting
 currents of 30 to 50 amps, the supply lines are to be provided with a
 large cross section. A reduction in the length of the supply lines
 therefore results in a large reduction in the production costs of the
 window and lens glass cleaning system according to the invention.
 Wipers of known window and lens glass cleaning systems for different
 windows and lenses of the motor vehicle in each case have their own
 electronic control units which enable them to be activated independently
 of one another. Furthermore, the known window and lens glass cleaning
 system has a further electronic control unit for activating heating
 elements for washer nozzles, washer fluid lines and the washer fluid
 container at low outside temperatures. Then, to further simplify the
 installation in the motor vehicle of the window and lens glass cleaning
 system according to the invention, it helps if at least one further
 electronic control unit of a heating device for the washer fluid, of a
 motor drive for moveable washer nozzles, of a multiway valve for
 distributing the washer fluid or of a wiper is fastened on the washer
 fluid container. Since this means that the control units for various
 components of the window and lens glass cleaning system are arranged in
 close proximity to one another, connecting up the control units to one
 another becomes particularly cost-effective. As a result, the operation of
 the wiper and of the washer nozzles, for example, can be very simply
 synchronized.
 To further simplify the installation of the window and lens glass cleaning
 system according to the invention it helps if an evaluating device of a
 fluid-level sensor is fastened on the washer fluid container. Since in
 this arrangement the fluid-level sensor and the evaluating device are
 arranged in close proximity to one another, this design results in
 particularly cost-effective manufacturing of the window and lens glass
 cleaning system according to the invention.
 According to another advantageous development of the invention, a plurality
 of fluid levels in the washer fluid container can be measured with
 particularly low constructional outlay if the fluid-level sensor has a
 plurality of contact plates embedded in the wall of the washer fluid
 container, for measuring the conductivity.
 According to another advantageous development of the invention, the
 electronic control units and the evaluating device of the fluid-level
 sensor can be connected to one another in a simple manner if a plurality
 of the electronic control units and the evaluating device of the
 fluid-level sensor form a constructional central processing unit. This
 design simplifies connecting up the control units to one another, so that
 the controls, for example, only require a single supply line for electric
 current. Furthermore, the invention means that the control units and the
 evaluating device of the fluid-level sensor can have common hardware, such
 as a processor, for example, and common software.
 The installation in the motor vehicle of the window and lens glass cleaning
 system according to the invention can be further simplified if the
 electronic control units and the evaluating device of the fluid-level
 sensor have a common connecting socket. Furthermore, this design enables
 the individual components of the window and lens glass cleaning system
 according to the invention to be connected in a very simple manner to a
 data bus.
 According to another advantageous development of the invention, the
 electronic controls are protected from damage with a low constructional
 outlay if the washer fluid container has a trough for accommodating the
 electronic control units or the electronic control unit.
 According to another advantageous development of the invention, the washer
 fluid container becomes particularly simple in terms of design if the
 trough can be closed by a lid which can be latched in the washer fluid
 container.
 According to another advantageous development of the invention, the lid can
 be manufactured together with the washer fluid container in a particularly
 cost-effective manner if the lid is connected to the washer fluid
 container on one side via a film hinge. Furthermore, this design
 simplifies the installation of the window and lens glass cleaning system
 according to the invention. Moreover, the lid is unable to be lost.
 According to another advantageous development of the invention an
 overfilling warning or a refilling indication for the washer fluid
 container can be generated with particularly low constructional outlay if
 an optical or acoustic signaling device for generating an overfilling
 warning and/or a signal when the fluid level falls short of the minimum is
 arranged on the evaluating device of the fluid-level sensor. This means
 that only an insignificant outlay for connecting up the signaling device
 is required. Furthermore, the invention means that the washer fluid
 container can be identified without a problem by the person refilling it.
 The easy identification simplifies the refilling, in particular in the
 case of a washer fluid container having separate chambers for washers,
 cleaning concentrate and antifreeze. A buzzer and a light-emitting diode
 are particularly suitable as the signaling device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
 FIG. 1 shows, schematically, a window and lens glass cleaning system
 according to the invention having a washer fluid container 1 and an
 electronic central processing unit 2. The washer fluid container 1 has
 three washer fluid pumps 3-5 and a heating device 6. Within the electronic
 central processing unit 2, a respective electronic control unit 7-9 for
 the washer fluid pumps 3-5, the heating device 6 and for two wipers 10, 11
 is arranged. Of course, the window and lens glass cleaning system
 according to the invention can have further control units, for example for
 moving washer nozzles or for operating a multiway valve for distributing
 washer fluid. Furthermore, the central processing unit 2 has an evaluating
 device 12 of a fluid-level sensor 12a for detecting a washer fluid level
 in the washer fluid container 1. The wipers 10, 11 and the washer fluid
 pumps 3-5 can be operated by operating elements 13. Of course, the wipers
 can additionally be connected upstream of a rain sensor (not shown). The
 heating device 6 is operated by one of the electronic control units 7-9 as
 a function of the outside temperature. The window and lens glass cleaning
 system according to the invention is protected by this means against
 freezing.
 The evaluating device 12 of the fluid-level sensor 12a has a plurality of
 contact plates 14 penetrating the wall of the washer fluid container 1,
 and generates, by means of measuring the conductivity, electrical signals
 as a function of the washer fluid level in the washer fluid container 1.
 The electrical signals are then evaluated and sent to a display 15 for a
 driver's cockpit of the motor vehicle or to a signaling device 16 having a
 light-emitting diode 17 and a buzzer 18. This enables either an
 overfilling warning or a refilling requirement to be signaled. In this
 arrangement, the refilling requirement can be displayed permanently or,
 for example, only while a fuel tank of the motor vehicle is being
 refilled.
 The electronic control units 7-9 and the evaluating device 12 have a common
 connecting socket 19, arranged on the upper side of the central processing
 unit 2, for a plug 20 of a supply network 21 of the motor vehicle. The
 supply network 21 is designed s a data bus and connects all of the
 electrical components of the window and lens glass cleaning system
 according to the invention. Furthermore, the electrical components are
 supplied with electric current via the supply network.
 The washer fluid pumps 3-5 serve for conveying washer fluid from the washer
 fluid container 1 via washer fluid lines 22 to washer nozzles 23 to be
 arranged in front of windows and lenses (not shown). The display 15 and
 the operating elements 13 are provided for arrangement in a passenger cell
 (not shown) of the motor vehicle.
 FIG. 2 shows a washer fluid container 24 having separate chambers 25-27 in
 each case for water, cleaning concentrate and antifreeze. The washer fluid
 container 24 has a trough 28 for accommodating a common electronic control
 unit 29 for the wipers (10, 11) and the washer fluid pump (3-5) which are
 shown in FIG. 1. The control unit 29 is protected by a lid 30.
 Furthermore, the electronic control unit 29 has a connecting socket 31 for
 a plug 32 of a data bus 34 and a connection 33 for supply lines 35 for
 supplying all of the window and lens glass cleaning system components
 arranged on or in the washer fluid container 24 with electric current.
 FIG. 3 shows the washer fluid container 24 from FIG. 2 in a sectional
 representation along the line III--III. In this case, it can be seen that
 the electronic control unit 29 is fitted between the lid 30 and the washer
 fluid container 24. A seal (not shown) and a dip-coating of the electronic
 control unit 29 ensure adequate protection against moisture. The lid 30 is
 connected to the washer fluid container 24 via a film hinge 36 and at its
 end which lies opposite the film hinge 36 has a latching connection 37 to
 the washer fluid container 24.