GB2253338A

GB2253338A - Vehicle screen wash

Info

Publication number: GB2253338A
Application number: GB9104440A
Authority: GB
Inventors: David George Rouse
Original assignee: Individual
Current assignee: Individual
Priority date: 1991-03-02
Filing date: 1991-03-02
Publication date: 1992-09-09
Anticipated expiration: 2011-03-02
Also published as: GB2253338B; GB9104440D0

Abstract

A vehicle screen wash system comprises two screen wash fluid containers 1, 2. Container l contains screen wash fluid of normal or summer concentration and container 2 fluid of stronger or winter concentration. Individual pumps 12, 13, when energised, supply fluid from containers 1, 2 respectively to jets 10S, 11S and low, 11W respectively. Jets 10W and 10S are grouped in a common jet block 10B, likewise jets 11S, 11W in common jet block 11B. All jets are individually adjustable. Pump 13 is arranged normally to be energised when the screen wash control is operated via relay 6. Relay 6 is controlled by a temperature sensor 7 so that pump 13 is energised instead of pump 12 upon sensor 7 detecting freezing conditions. Relay 6 is also controlled to the same effect by a pressure sensitive device 20 if it detects pressure in the line between pump 12 and jets 10S, 11S indicative of blocked jets, e.g. by being frozen and unthawed despite a rise in ambient temperature. <IMAGE>

Description

Improvements in or Relating to Vehicle Screen Wash Arranqements This invention relates to vehicle screen wash arrangements and in particular, though not exclusively, to such arrangements used in automobiles and other land vehicles.

It is common practice to use as the screen washing fluid a mixture of water and an additive which consists of both a detergent or other soap-like material and an anti-freezing agent, the concentration of the additive being greater for winter use than it is for normal or summer use.

The added concentration used in winter is of course primarily to combat freezing effects not only on the screen, but also within the jet or jets which project fluid onto the screen.

Whilst satisfactory if a sufficient concentration is used in freezing conditions two problems are commonly apparent. Firstly, with a winter concentration, the screen cleaning liquid is usually too "soapy" for normal temperatures and the screen tends to be left with an undesirable film upon it and in some cases dries streaky.

Since such temperature changes can occur within the course of a day and night, it is not convenient to overcome the problem by diluting the screen wash fluid.

The second problem commonly apparent arises when the concentration of the screen wash fluid is insufficient to resist freezing with the consequential freezing up of the screen wash jets In this last case the problem is greatly exacerbated by the fact that most modern systems are arranged such that windscreen wiper action commences with the operation of the screen wash so that the wipers wipe automatically whether or not the screen has been wetted. In consequence dirt is spread in streaks across the screen obscuring vision, in extreme cases, virtually totally.

The present invention seeks to provide an improved vehicle screen wash system in which the above problems are mitigated.

According to this invention a vehicle screen wash system includes two washer fluid containers, one of which may contain screen wash fluid of a normal or summer concGntration and the other of which may contain a stronger or winter concentration of screen wash fluid, means being provided whereby screen wash fluid may be drawn from one or other of said containers in dependence upon the external temperature.

In one embodiment of the invention screen wash fluid is arranged to be drawn from one or other of said containers by a common screen wash pump via a changeover valve.

Said changeover valve may be arranged to be operated manually or arranged to be operated by means of a temperature sensitive device arranged to set said valve to source fluid from one container when the external temperature is above a predetermined level and from the other container when the external temperature falls below said predetermined level.

Said predetermined level may be zero, but is conveniently closely above zero, for example one or two degrees centigrade. Where said controllable changeover valve is controlled by a temperature sensitive device, said valve will normally be an electrically operated changeover valve which is arranged to be energised through a relay controlled by said temperature sensitive device.

In another embodiment of the invention an individual screen wash pump is provided for each container, said pumps being arranged for selective operation in dependence upon temperature.

In the last-mentioned case in which an individual screen wash pump is provided for each container the output of each pump may be combined, for example by a simple T piece connector, and arranged to supply a common screen wash jet or jets. If required, simple one-way valves may be provided between the output of each pump and the means for combining the outputs of the same.

Preferably however each pump is arranged to supply y a dedicated jet or set of jets.

Preferably two groups of jets are provided one for wetting the nearside of the screen and the other for wetting the offside of the screen.

Preferably a group of jets is provided comprising a jet arranged to be supplied by one of said pumps and a jet arranged to be supplied by the other of said pumps the or each group of jets being mounted in a common jet carrier and arranged to be individually adjustable directionally.

Said pumps may be arranged to be controlled manually, by individually operable switches or by a common switch using relays if appropriate. Preferably however said pumps are arranged to be controlled by a temperature sensitive device whereby normally the pump connected to source fluid from the screen wash fluid container provided to contain screen wash fluid of a normal or summer concentration is energised when the screen wash control is operated and said other pump is energised in its stead when the temperature sensitive device detects temperatures below a predetermined level.

Preferably again, means are provided for detecting pressure in the line between the output of the pump connected to source fluid from the container provided to contain screen wash fluid of a summer or normal concentration and the jet or jets supplied thereby, said pressure detecting means being arranged to energise said other pump upon detection of a pressure indicative of a blocked jet or jets.

Fluid level detectors may be provided in said containers arranged to override said temperature detecting device whereby in periods when freezing is unlikely, fluid is sourced first from one and then, when that one is effectively empty, the other. With such an arrangement, both containers may be filled with screen wash fluid of normal or summer concentration during such period so as to provide a reserve. A warning lamp indicating low washer level may be arranged to light when said first container is empty. As will be appreciated, the development of within cockpit vehicle condition displays offer wide opportunities for indicating to a user the status of the screen wash system described above.

It will be appreciated that the two containers need not be physically separate. They may be provided as a single partitioned tank one container being constituted by one part of the tank to one side of the partition and the other container being constituted by another part of the tank to the other side of the partition.

Whilst most conveniently embodied as original equipsdent on a vehicle, the system in accordance with the present invention is suitable for retrospective fitting and is therefore suitable for supply in kit form.

The invention is illustrated in and further described with reference to the accompanying drawings in which Figures 1 to 3 illustrate in block schematic form three examples of automobile screen washing arrangements in accordance with the present invention. In all Figures, like references are used to denote like parts.

Referring to Figure 1, a first container 1 is provided to hold screen washing fluid of normal summer strength. A second container 2 is provided to contain screen washing fluid of winter strength, that is to say of a concentration considerably stronger than that contained in container 1 so as to be resistant to freezing. Lengths of polythene tubing 3,4 are provided to conduct fluid from containers 1 and 2 respectively to an electrically operated changeover valve 5 which is controlled via a relay 6 by a temperature sensing device 7 of a nature similar to that used in ice alert systems as known per se.The arrangement is such that upon temperature sensing device 7 detecting a predetermined low temperature (which may be zero degrees centigrade, but in practice would be a degree or two higher than this) relay 6 closes to switch valve 5 over so that fluid is drawn from container 2 (winter concentrate) and not container 1 (summer concentrate). Upon a predetermined rise in temperature detected by temperature sensor 7 relay 6 opens again and changeover valve 5 reverts to its former state in which fluid is drawn from container 1 (summer concentrate).

The output of changeover valve 5 is connected via a screen washer pump 8 to supply fluid via a T piece connector 9 to spaced screen washer jets 10 and 11 set to direct fluid towards the nearside and offside of the automobile's front windscreen (not shown).

Although not shown, it will be appreciated that provision may be made for a rear screen wash by taking a further tapping from the output of screen wash pump 8 or by providing another, dedicated, screen wash pump connected to the output of electrically controllable valve 5.

It will also be appreciated that the system may be simplified considerably for some applications by providing a simple manually operated changeover valve in place of the electrically controllable valve 5 in the embodiment of Figure 1.

Referring to Figure 2, in this embodiment the use of an electrically controllable changeover valve such as 5 in Figure 1 is avoided by providing a separate screen wash puwtp 12,13 respectively for each of the containers 1,2. The outputs of screen wash pumps 12,13 are passed through respective one-way valves 14,15, permitting fluid flow in the direction of the arrows 16,17. Instead of controlling an electrically controllable valve 5 temperature sensor 7 and relay 6 control the operation of screen wash pumps 12,13 so as to achieve a corresponding effect to that achieved by the arrangement of Figure 1.

Whilst obviously the embodiments illustrated in Figures 1 and 2 have advantages over a standard system in which one container has to be filled with either screen cleaning fluid of summer concentration or screen cleaning fluid of winter concentration at the operator's discretion, it is still possible that jets 10 and 11, having previously been operated with screen washer fluid of summer concentration, could freeze whilst the vehicle is parked, especially overnight, as in fact commonly occurs with present known systems. The use of electrically heated screen washer jets would obviate this difficulty, but nevertheless the system illustrated in Figure 3 is to be preferred for this reason.

Referring to Figure 3, as with the embodiment shown in Figure 2, a separate screen wash pump 12,13 respectively is provided for each of the containers 1,2. With relay 6 in its "normal" setting with temperaure sensor 7 detecting non-freezing conditions, pump 12 is energised when the washer control (not shown) is operated and voltage is applied to terminal +ve.

Instead of the outputs of pumps 12,13 being combined as in the embodiment of Figure 2 however each is connected to a respective T piece 18,19 and instead of simple screen wash jets 10 and 11, the screen wash jet assemblies for the nearside and offside of the automobile's front windscreen (again not shown) consist of pairs of jets lOS,lOW and 115 and 11W in common jet blocks lOB and llB respectively. Jets 105 and lOW are mounted to wet one side of the windscreen and jets 115 and 11W are mounted to wet the other side of the windscreen.As will be apparent from the previous description referring to Figure 2 and the above, jets 105 and 115 operate with screen wash fluid of summer concentration when temperature sensor 7 detects normal (non-freezing) conditions and jets lOW and 11W operate with screen wash fluid of winter concentration when temperature sensors device 7 detects low or freezing temperatures, the appropriate pump 12,13 being activated by the relay 6, as previously described.

All of the jets are individually adjustable within their jet blocks. This enables adjustment to be made to take into account the different "reach" with different concentrations of screen wash fluids.

With an arrangement as just described with reference to Figure 3 jets lOW and 11W only operate with screen wash fluid of winter concentration and therefore should remain free from freezing up even though jets lOS and 115 operating with screen wash fluid of summer concentration may freeze up whilst the vehicle is parked, for example overnight.

In order to avoid any problem arising due to temperature sensor 7 detecting a normal (non-freezing) condition and thus causing pump 12 to operate whilst screen jets 105 and 115 may still be frozen, a pressure sensitive device is connected to monitor pressure at the output of pump 12 and to provide an input to relay 6 with, or in the absence of, an enabling signal from temperature sensor 7 so that relay 6 operates to energise pump 13.

Whilst the detailed construction of pressure sensor 20 is not shown, this may be of any convenient form, for example a light bellows connected in line between the output of pump 12 and the T piece 19 with a microswitch positioned to be operated if the bellows expand to an extent indicating a blocked jet 105 or 115.

Whilst not illustrated, it is further possible, if desired, to include fluid level sensors within containers 1 and 2 which are arranged, selectively if desired, to override the action of relay 6 so that if one of the containers 1,2 is empty the pump, 13,12 sourcing fluid from the other container 2,1 is operated irrespective of the outputs of temperature sensor 7. Conveniently in such a circumstance a "low washer fluid" indicator lamp would be arranged to be lit as one pump is energised instead of the other. It will be appreciated that such a system offers the possibility of using the container 2, filled not with screen washer fluid of winter concentration, but with screen washer fluid of summer concentration, as a reserve during periods when freezing is not expected.

Claims

What I claim is:

1. A vehicle screen wash system including two washer fluid containers, one of which may contain screen wash fluid of a normal or summer concentration and the other of which may contain a stronger or winter concentration of screen wash fluid, means being provided whereby screen wash fluid may be drawn from one or other of said containers in dependence upon the external temperature.

2. A system as claimed in claim 1 and wherein the arrangement is such that screen wash fluid is drawn from one or other of said containers by a common screen wash pump via a changeover valve.

3. A system as claimed in claim 2 and wherein said changeover valve is of a kind operated manually.

4. A system as claimed in claim 2 and wherein said changeover valve is arranged to be operated by means of a temperature sensitive device arranged to set said valve to source fluid from one container when the external temperature is above a predetermined level and from the other container when the external temperature falls below said predetermined level.

5. A system as claimed in claim 4 and wherein said predetermined level is zero degrees centigrade.

6. A system as claimed in claim 4 and wherein said predetermined level is closely above zero degrees centigrade.

7. A system as claimed in any of claims 4 to 6 and wherein said valve is an electrically operated changeover valve which is arranged to be energised through a relay controlled bv said temperature sensitive device.

8. A system as claimed in of claim 1 and wherein an individual screen wash pump is provided for each container, said pumps being arranged for selective operation in dependence upon temperature.

9. An arrangement as claimed in claim 8 and wherein the output of each pump is combined and arranged to supply a common screen jet or jets.

10. A system as claimed in claim 9 and wherein one-way valves are provided between the output of each pump and the means for combining the outputs of the same.

11. A system as claimed in claim 8 and wherein each pump is arranged to supply a dedicated jet or set of jets.

12. A system as claimed in claim 11 and wherein two groups of jets are provided one for wetting the nearside of the screen and the other for wetting the offside of the screen.

13. A system as claimed in claim 11 or 12 and wherein a group of jets is provided comprising a jet arranged to be supplied by one of said pumps and a jet arranged to be supplied by the other of said pumps, the or each group of jets being mounted in a common jet carrier and arranged to be individually adjustable directionally.

14. A system as claimed in any of claims 11 to 13 and wherein said pumps are arranged to be controlled manually, by individually operable switches.

15. A system as claimed in any of claims 11 to 13 and wherein said pumps are arranged to be operated manually by a common switch using relays if appropriate.

16. A system as claimed in any of claims 11 to 13 and wherein said pumps are arranged to be controlled by a temperature sensitive device whereby normally the pump connected to source fluid from the screen wash fluid container provided to contain screen wash fluid of a normal or summer concentration is energised when the screen wash control is operated and said other pump is energised in its stead when the temperature sensitive device detects temperatures below a predetermined level.

17. A system as claimed in any of claims 11 to 16 and wherein means are provided for detecting pressure in the line between the output of the pump connected to source fluid from the container provided to contain screen wash fluid of a summer or normal concentration and the jet or jets supplied thereby, said pressure detecting means being arranged to energise said other pump upon detection of a pressure indicative of a blocked jet or jets.

18. A system as claimed in claim 16 or claim 17 as dependent upon claim 16 and wherein fluid level detectors are provided in said containers arranged to override said temperature detecting device whereby in periods when freezing is unlikely, fluid is sourced first from one and then, when that one is effectively empty, the other.

19. A system as claimed in claim 18 and wherein a warning lamp indicating low washer level is arranged to light when said first container is empty.

20. A system as claimed in any of the above claims and wherein the two containers are provided as a single partitioned tank one container being constituted by one part of the tank to one side of the partition and the other container being constituted by another part of the tank to the other side of the partition.

21. A vehicle screen wash system substantially as herein described with reference to Figure 1 of the accompanying drawings.

22. A vehicle screen wash system substantially as herein described with reference to Figure 2 of the accompanying drawings.

23. A vehicle screen wash system substantially as herein described with reference to Figure 3 of the accompanying drawings.