GB2198261A

GB2198261A - Heating vehicle windscreens

Info

Publication number: GB2198261A
Application number: GB8627215A
Authority: GB
Inventors: Scan Martin Burton
Original assignee: Individual
Current assignee: Individual
Priority date: 1986-11-14
Filing date: 1986-11-14
Publication date: 1988-06-08
Also published as: GB8627215D0

Abstract

A time controllable switching arrangement for use with a motor vehicle is adapted for switching-on screen heating means 6 at a predetermined time interval prior to a desired time of departure of the vehicle. This can be varied in accordance with ambient temperature. The condition of the vehicle battery 5 is monitored at 13 to prevent excessive draining. Other heaters and wipers 3, 4, 7 may be controlled also. <IMAGE>

Description

VEHICLES This invention is concerned with motor vehicles, and in particular to the equipment provided on such vehicles.

It is well known that the modern motor vehicle is provided with a wide range of equipment which is primarily intended to add not only to the comfort of the user but also to enhance both the safety of and the ease of using such vehicles.

For example, most motor vehicles are provided with front and rear windscreens which comprise relatively large areas of glass. Because of the physical characteristics of glass the surfaces both inside and out are, under certain ambient conditions, susceptable to the depositioning of water vapour, dew, or the like so that the vehicle screens frequently become coated with a translucent layer of deposited material. Also under conditions of cold weather in which the temperature falls below the freezing point this translucent layer turns to a hard frozen layer.

Solutions have been proposed for dealing with this problem. In particular, it has become relatively common place to provide the rear screen of a vehicle with a heating arrangement which serves to heat sufficiently a region of or the total screen area to melt or evaporate any deposited layer thereby to clear the screen. As an additional aid to the fitted heating arrangements it is also known to apply deicing fluids to the external surfaces of the screen to accelerate the melting process.

It will also be appreciated that the front screen will likewise become coated with the translucent layer.

In the case of the front screens it is the a common practice to rely upon the heat of the vehicle heating system to produce a sufficient circulation of heated air to remove any internally deposited water vapour and to melt any external frozen layer and thus enable removal of the deposited material by operation of wiper blades which are arranged to sweep across the external surface of the screen. It is convenient to note that some vehicles are also provided with a wiper blade for wiping the rear windscreen.

In addition, when the temperature is relatively low it is a further common practice to use the deicing fluids to accelerate the removal of the translucent layer.

Unfortunately, as may be readily noted on any cold morning many motorists need to devote a considerable amount of time to the operation of cleaning-off the inside and outside surfaces of the front and rear screens. Furthermore, there is the additional problem of it also being necessary similarly to treat the vehicle side windows. As a consequence of shortage of time impatience or other reasons many motorists commence driving before the rear screen has even commenced to become adequately transparent, with the side screens totally translucent and with the front screen only partially cleared, even though it is well known that to drive with driving visibility thus restricted is essentially very dangerous.

It is believed that a fundamental reason for motorists driving with such reduced visibility resides in the simple fact that such motorists need to arrive at a desired destination by a particular time whilst using as their time of departure one which leaves inadequate time for the screen cleaning process to be adequately carried out before it is vitally necessary for them actually to start driving.

Bearing in mind that many such drivers start their journeys at a substantially regular time each day it is proposed according to the invention to provide means whereby the or at least selected ones of screen cleaning arrangements provided on the vehicle are set into operation at a preselectable period of time before the motorist requires to commence a journey.

Thus according to an aspect of the invention a motor vehicle is provided with time controllable switching arrangements for switching-on screen heating means at a predertemined time interval prior to a desired time of departure of the vehicle.

Preferably, temperature responsive means are provided for detecting the ambient temperature conditions and for adjusting the time for switching-on the control arrangements in advance of a defined departure time.

In accordance with an still further aspect of the invention, the apparatus includes means for monitoring the condition of the battery of the vehicle in such manner that if the state of charge of the battery is inadequate to support, in addition to the starting of the vehicle, energisation of the screen heating arrangements means are provided for correspondingly adjusting the duration of any preheating time period so that the front and/or rear screen clearing i.e., defrosting operations can be at least started with out jeopardising the ability of the battery to provide the essential starting power source of the vehicle.

Preferably means are provided for providing an indication to a vehicle user of the extent of the preheating time effected so as to provide a guide to the user of the extent of use of the vehicle battery and information as to the preheating time periods required.

In a particular arrangement a switching system is provided comprising a number of time switches which may be respectively connected for example to the rear screen heater; the front screen wiper the rear screen wiper, and a front screen heater unit, if fitted. The switches are arranged operation for relay or other mode of operation responsive to the output signals of a time control unit producing one or more electrical signals at a common predetermined time or at various times according to a predetermined time sequence which serve to actuate the previously mentioned relays. The switching system is connected to be energised from the car battery or from an external current supply as may be the case where a vehicle is housed In a garage or closely adjacent to a building. It is in these latter situation that the proposals of the invention are intended to be used.

To ensure that the utilisation of the system of the invention does not produce an excessive drain on the charge stored by the vehicle battery the system can incorporate means for checking the charge of the battery. This can conveniently be a voltage measuring means which is arranged to produce an output signal when the battery voltage level falls to a level at which the charge condition of the battery would not be able to enable to deliver the heavy currents required for the starting of a cold vehicle engine which output signal is used to operate a cut-off switch which disconnects the vehicle battery from the system of the invention.

Preferably, means are provided for indicating that the apparatus has been switched-off as a result of the operation of the battery condition detection means.

For a better understanding of the invention and to show how to carry the same into effect reference will now be made to the accompanying drawing which very schematically indicates in block diagrammatic form a system incorporating the concepts of the invention.

In the Figure the front and rear screens of a vehicle (not shown) are indicated at 1 and 2 respectively. The rear screen has an associated heater 3 and screen wiper 4. The heater and wiper are connectable by way of the conventionally provided control switches 3A and 4A to the vehicle battery 5. The front screen 1 has an associated heater arrangement 6 and wiper arrangement 7 which are connectable to the battery 5 by way of conventionally provided switches 6A and 7A respectively. This front screen arrangement 4 can comprise a heating element provided in the vehicle front screen air blower arrangement (not shown) conventionally provided on vehicles and/or a heater strip or heater zone associated with the screen itself.

The switching system 8 of the invention incorporates a series of relay units 9A, 9B, 9C, 9D, having their control Inputs lOA, lOB, lOC, lOD, etc connected to the signal outputs llA, liB, llC, liD, of a timer circuit 12 settable or programmable to produce output signals at its outputs which are selectively time related to each other. That is the outputs can be simultaneous or time spaced as required.

The relay units are connected to control the operation of switches 3B, 4B, 6B and 7B, etc., which are respectively connected to control operation of the heater 3, the wiper 4, the heater 6 and the wiper 7. by connecting the battery 5 through the switches 3B, 4B, 6B, 7B etc., to the associated heaters and wipers.

In the event that it is desired that the screen wipers should be operated it will be necessary to ensure that the wipers are not operated until any ice coating has adequately melted prior to using the wipers thereby to avoid the risk of damage to the wiper system.

It will be understood that whilst separate switches have been shown for the time control of the above mentioned heaters and wipers it will be appreciated that the conventionally provided switches could be utilised provided that their normal or conventional operation is not disturbed.

A battery condition monitor 13 is arranged to monitor the instantaneous condition of the battery and to produce an output control signal which, whenever the charge condition of the battery is at or less than a level at which further drain on the battery would prevent efficient starting, disables the switching control unit. The condition monitor 13 has an output 14 which is arranged to actuate indicator means 15 which provides an indication that the switching control unit has been switched-off to conserve the battery charge.

Claims

1. A time controllable switching arrangement for use with a motor vehicle, wherein the switching arrangement is adapted for switching-on screen heating means at a predetermined time interval prior to a desired time of departure of the vehicle.

2. A time controllable switching arrangement as claimed in claim 1, wherein temperature responsive means are provided for detecting the ambient temperature conditions in the vicinity of the vehicle and for producing an output characteristic of such detection, and wherein means responsive to said output is provided for adjusting the time for switching-on the control arrangements in advance of a predefined departure time.

3. A time controllable switching arrangement as claimed in claim 1 or 2, and wherein means are provided for monitoring the condition of the battery of the vehicle in such manner that if the state of charge of the battery is inadequate to support, in addition to the starting of the vehicle, energisation of the screen heating arrangements, means are provided for correspondingly adjusting the duration of any preheating time period so that the front and/or rear screen clearing i.e., defrosting operations can be at least started without jeopardising the ability of the battery to provide the essential starting power source of the vehicle.

4. A time controllable switching arrangement as claimed in claim 1,2 or 3, and wherein means are provided for providing an indication to a vehicle user of the extent of the preheating time effected so as to provide a guide to the user of the extent of use of the vehicle battery and information as to the preheating time periods required.

5. A time controllable switching arrangement as claimed in claim 1,2,3 or 4, and including a switching system comprising a number of time switches which may be respectively connected to control operation of any of a plurality of components provided on the vehicle.

6. A time controllable switching arrangement as claimed in claim 5, wherein said components can include components such as a rear screen heater; a front screen wiper; a rear screen wiper; and, if fitted, a front screen heater unit.

7. A time controllable switching arrangement, wherein the switches are arranged for relay or other mode of operation responsive to the output signals of a time control unit producing one or more electrical signals at a common predetermined time or at various times according to a predetermined time sequence which signals serve to actuate the previously mentioned relays, and wherein the switching system is connected to be energised from the car battery or from an external current supply as may be the case where a vehicle is housed in a garage or closely adjacent to a building.

8. A time switchable arrangement as claimed in any of the preceding claims, and wherein means are provided for checking the instantaneous charge level of the vehicle battery, the arrangement being such as to ensure that the utilisation of the switchable arrangement does not produce an excessive drain on the charge stored by the vehicle battery.

9. A time switchable arrangement as claimed in claim 8, and wherein the charge level detection means includes a voltage measuring means which is arranged to produce an output signal when the battery voltage level falls to a level at which the charge condition of the battery would not be able to deliver the heavy currents required for the starting of a vehicle engine when the latter is cold, which output signal is used to operate a cut-off switch which disconnects the vehicle battery from the switchable arrangement.

10. A time switchable arrangement as claimed in any of the preceding claims, wherein means are provided for indicating that the apparatus has been switched-off as a result of the operation of the battery condition detection means.

11. A time switchable arrangement constructed and arranged to operate substantially as hereinbefore described with reference to the accompanying drawings.