GB2431734A

GB2431734A - Windscreen wiper control

Info

Publication number: GB2431734A
Application number: GB0521994A
Authority: GB
Inventors: Pedro Diaz
Original assignee: Nissan Motor Manufacturing UK Ltd; Nissan Technical Centre Europe Ltd
Current assignee: Nissan Motor Manufacturing UK Ltd
Priority date: 2005-10-28
Filing date: 2005-10-28
Publication date: 2007-05-02
Anticipated expiration: 2025-10-28
Also published as: GB2431734B; GB0521994D0

Abstract

A windscreen wiper control system comprising is provided. The system comprises a controller 16 which is arranged to receive user input signals and determine a time interval between received user input signals. The controller is also configured to generate output signals for causing a wiper mechanism to provide a wipe frequency that is a function of the time interval. The system further comprises a switching arrangement 20 connected with the controller 16, the switching arrangement 20 being operable to have a relatively short duration contact position by which the user can cause the controller 16 to generate an output signal for causing the wiper mechanism 10, 14 to provide a single wipe. The controller 16 is arranged to treat each operation of the switching arrangement 20 to the relatively short duration contact position as a user input signal. The controller 16 is arranged to determine the duration of a contact made by the operation of the switching arrangement 20 to the relatively short duration contact position and, when the duration is greater than a predetermined threshold, determine that the user input signal is a stop signal for the wiper mechanism 10, 14.

Description

CONTROL OF WINDSCREEN WIPERS

The invention relates to the control of windscreen wipers and particularly, but not exclusively, to the control of windscreen wipers of automobiles.

The windscreen wiper, or wipers, of automobiles is/are caused to reciprocate by an electric motor so as to produce a wiping action by means of which water is removed from the windscreen. Typically, the system for controlling the wipers includes switching that allows the driver to select one or more continuous wiping io frequencies (speeds).

There are occasions in which the amount of water falling on the windscreen is not sufficient to require continuous wiping. Some systems for controlling windscreen wipers include a flick (single) wipe andlor an intermittent wipe feature. In is systems having an intermittent wipe feature, the can driver operate the switching to cause intermittent wiping of the windscreen at a frequency set by the system.

For example, the intermittent wipe feature might be set to cause the wiper to wipe the windscreen at 10 second intervals.

In systems having a flick wipe feature, the driver can cause the wiper to wipe the screen once by operating the switching. The switching typically comprises a lever projecting from the steering column and a flick wipe is obtained by operating the lever such that a momentary switch contact is made and then releasing the lever to break the contact.

Flick and intermittent wiping is useful for coping with light rainfall. However, it is bothersome for the driver to have to repeatedly actuate the switching of a flick wipe system when such light rainfall is prolonged and, while an intermittent wipe system overcomes this problem, the set frequency of wiping may not be best suited to the amount of water deposited on the windscreen.

Systems have been developed in which sensors (that may be embedded in the windscreen) are provided for detecting the amount of water on the windscreen and controlling the wiper frequency in accordance with signals received from the sensors. This allows the wiper frequency to be matched to the amount of water on the windscreen. Such systems are disclosed by GB2,274,925, US5,684,464 and W089/06202. These systems suffer from the disadvantage of being relatively complex and involve the additional cost of providing sensors for detecting water falling on the windscreen and circuitry connecting the sensors to the wiper control system.

It is an object of the present invention to avoid the above described problems is and/or provide an alternative to existing windscreen wiper controls.

According to a first aspect of the present invention, there is provided a method of controlling the wipe frequency of a windscreen wiper, the method comprising determining a time interval between a first user input signal and a second user input signal and causing the windscreen wiper to wipe at a frequency that is a function of the time interval.

The method is particularly applicable to automobile applications, and particularly for controlling the windscreen wiper frequency of the front and/or rear wipers.

Advantageously, the method further comprises changing the wipe frequency to cause the windscreen wiper to wipe at a frequency that is a function of a time interval between a third user input signal and a fourth user input signal, the third and fourth user input signals being provided after the second user input signal.

This allows the user to reset the wipe frequency to suit prevailing conditions.

Preferably, the method includes operating a means for causing the windscreen wiper to perform a single wipe so as to provide the user input signals. The means is preferably a lever arm for operating the windscreen wiper.

However, in an alternative embodiment the user input signals could be provided by, for example, operation of a button/key that will not in itself cause a wiping action.

Typically, the wipe frequency will be substantially equal to the time interval.

However, this is not essential and, for example, the wipe frequency could be the time interval minus a predetermined amount, or minus a predetermined percentage of the time interval.

According to a second aspect of the invention, there is provided a windscreen wiper control system comprising a controller arranged to receive at least two user input signals, determine a time interval between received user input signals, and generate an output signal for causing a wiper mechanism to provide a wipe frequency that is a function of the time interval.

The controller may be a body control module for an automobile.

The control system may further comprise a switching arrangement connected with the controller. The switching arrangement is preferably operable to have a relatively short duration contact position (i.e. a switch contact which is only connected for a short time) by which the user can cause the controller to generate output signals for causing the wiper mechanism to provide a single wipe. The controller is arranged to treat each operation of the switching arrangement to the relatively short duration contact position as a user input signal. In the application of the invention to automobiles, the switching arrangement may be configured to be fitted to a steering colunm and comprise a lever arm by which the driver actuates the switching arrangement.

The controller can be arranged to determine the duration of a contact made by the operation of the switching arrangement to the relatively short duration contact position and, when the duration is greater than a predetermined threshold, determine that the user input signal is a stop signal which halts the wiper mechanism.

Typically, the wipe frequency is substantially equal to the time interval.

However, software in the controller could set a frequency that is greater or less than the time interval by a predetermined amount, or percentage, of the time interval.

According to a third aspect of the invention, there is provided a wiper control system including means for driving a wiper with a reciprocating motion and control means for controlling the frequency of the reciprocating motion, wherein the control means is operable to determine the frequency as a function of a time interval between two user input signals.

In this specification, reference is made to first, second, third etc user input signals but it is understood that this is not intended to be limiting and the first, second and third etc identification is merely to represent the order of the signals in relative, and not absolute, terms.

It will be appreciated that preferred andlor optional features of the method of the first aspect of the invention can be implemented within the wiper control system of the second or third aspects of the invention also, alone or in appropriate combination.

The present invention will now be described, by way of example only, with reference to Figure 1, which is a schematic representation of a windscreen wiper mechanism and a windscreen wiper control system in accordance with an embodiment of the invention.

Referring to Figure 1, a windscreen wiper mechanism comprises a windscreen wiper 10 for wiping the windscreen 12 of an automobile (not shown) and a motor 14 for driving the wiper 10. The motor 14 is powered by the battery of the automobile and is connected to the wiper 10 in such a way that it can move the wiper back and forth over the windscreen. The windscreen wiper mechanism may be of any conventional type and need not be explained in detail for an understanding of the invention.

Operation of the windscreen wiper mechanism is controlled by a windscreen wiper control system that comprises a controller 16, a relay stage 18 and a switching arrangement 20. The controller 16 comprises a microcomputer 22 and is preferably the body control module of the automobile. The controller 16 is connected to the electric motor 14 via the relay stage 18 and to the switching arrangement 20. The switching arrangement 20 is used by the driver to control the operation of the windscreen wiper 10. The microcomputer 22 includes both read only and random access memory and the controller includes suitable input and output stages 24 to permit the microcomputer to receive signals from the switching arrangement 20 and output signals to the motor 14.

The switching arrangement 20 includes an arm projecting from the steering colunm of the automobile, detent positions for continuous and intermittent wiper operation and a momentary contact position for a flick (single) wipe. The switching arrangement 20 may be of any conventional type and will not, therefore, be described in any further detail.

The controller 16 has software stored within the read only memory that enables it to generate output signals for causing the windscreen wiper 10 to be driven continuously at a frequency that is a function of the time interval between two user input signals. In the embodiment, a user input signal comprises an operation of the switching arrangement 20 to provide a flick wipe. Specifically, when the driver operates the switching arrangement 20 to provide a flick wipe and then within a predetermined period of time t operates the switching arrangement to provide a second flick wipe, the software uses this information to cause the controller 16 to provide output signalling to the motor 14 such that the motor causes the windscreen wiper 10 to wipe at a frequency equal to the time interval between the first and second operations of the switching arrangement 20. Thus, the wiping frequency is a function of the time interval between the two user input signals and it can be assumed that the wiping frequency provided will be matched to the amount of rainfall on the windscreen, or, at least, the driver's perceived need for use of the windscreen wiper 10 to clear that amount of rainfall.

More specifically, when the driver operates the switching arrangement 20 to provide a flick wipe, this is noted as a first user input signal and a monitoring routine is initiated in the software stored in the controller 16. The operation of the switching arrangement 20 to provide a flick wipe involves holding the switching arrangement 20 in a contact position for only a relatively short duration of time.

For a predetermined period of time t after the first user input signal the software looks for a second operation of the switching arrangement 20 to provide a flick wipe. The time t is monitored using the internal clock of the microcomputer 22.

If there is no second operation within that period of time t1, the monitoring routine ceases. In this circumstance, it can be assumed that, for whatever reason, the driver required only a single wipe to remove the water on the windscreen.

If within the time period, t, there is a second operation of the switching arrangement 20 to provide a flick wipe, this is noted as a second user input signal and the time interval, t1, between the two user input signals is determined by reference to the clock of microcomputer 22. The software then causes the controller 16 to output signals to the motor 14 such that the motor causes the is wiper 10 to wipe at a frequency f1 that is equal to the time t1 until there is a further operation of the switching arrangement 20 (third user input signal).

When the software notes a third user input signal, it checks the duration of the signal. If the switching arrangement 20 is held in the flick wipe position for a prolonged period of time t, as distinguished from the relatively short duration contact position, this is considered to be a stop signal. For example, if the switching arrangement 20 is held in the flick wipe position for a period of time t, greater than 2 seconds, this is considered to be a stop signal and the software causes the controller 16 to cease outputting signals to the motor 14 and operation of the windscreen wiper 10 ceases until there is a further user input signal indicating that wiping is required. If the third user input signal is constituted by an operation of the switching arrangement 20 to produce a flick wipe that has a duration not greater than 2 seconds, a new monitoring routine is established and the software looks for a further operation of the switching arrangement 20 to produce a flick wipe, which is treated as a fourth user input signal.

The duration of the fourth user input signal is checked by reference to the clock of the microcomputer of the controller 16 in the same way as the third user input signal. If the duration is greater than the time period t (2 seconds), the fourth user input signal is treated as a stop signal. If the duration of the fourth user input signal is not greater than 2 seconds, the time interval t2 between the third and fourth user input signals is determined. The software then causes the controller 16 to output signals to the motor 14 that will cause the windscreen wiper 10 to wipe at a frequency f2 that is equal to the time interval t2. The wiper 10 is then caused to continue to wipe at the frequency f2 until there is a further operation of the switching arrangement to provide a flick wipe (fifth user input signal). As with the third user input signal, the fifth user input signal can either be an operation of the switching arrangement 20 that is considered to be a stop signal, or an operation that causes the software to commence a new monitoring routine awaiting a sixth user input signal.

The embodiment provides a simple and economic method and apparatus that permits the driver to obtain a wipe frequency that is matched to the amount of water on the windscreen and is not limited to wiping at set frequencies stored in the windscreen wiper controller. In particular, it will be appreciated that unlike the systems disclosed in GB2,274,925, US5,684,464 and W089/06 202 the embodiment does not require the provision of sensors and circuitry to connect the sensors to the controller. Indeed, any conventional wiper system incorporating a flick wipe feature can be adapted to embody the invention simply by providing suitable software in the controller. This provides the possibility of upgrading the control systems of existing automobiles.

It will be appreciated that the absence of sensors and the associated circuitry should make a windscreen wiper control system incorporating the invention more reliable than the systems disclosed by GB 2 274 925, US 5 684 464 and WO 89/06 202 since there are fewer parts that can fail or be damaged.

The invention is not limited to providing a wipe frequency that is equal to the time interval between user input signals. For example, the software may be arranged such that the output signalling to the motor 14 causes the wipe frequency to be somewhat greater than the time interval between the user input signals. This would be on the assumption that drivers will tend to delay the second flick wipe longer than is desirable to obtain optimum wiping.

Alternatively, or in addition, if the time interval between the two user input signals is not greater than a predetermined threshold t, the software may be is arranged to cause the controller to output signalling that will produce a wipe frequency that is less than the time interval. A modification of this alternative would be for the software to disregard the second of two user input signals (i.e. the second, fourth, sixth described above) if the time interval does not exceed the threshold t and use the third user input signal to be received once the threshold has been exceeded. These measures would avoid producing an undesirably fast wipe in cases where the driver inadvertently operates the switching arrangement twice in relatively quick succession.

It will be appreciated that the invention is not limited to the control of front windscreen wipers. It can also be applied to the control of rear wipers and wipers used to clean the lens of a light, such as the head or fog lights of an automobile.

To save the driver having to individually set a wipe frequency for each of the front and rear wipers, the same output signalling from the controller could be used to control the respective motors so that the front and rear wipers operate at the same frequency.

It will be understood that it is not essential that the controller comprises the body control module of an automobile. It can instead comprise another control module or be a dedicated controller for the windscreen wiper system. Furthermore, although the embodiment has only one windscreen wiper, the invention can be applied to the control of windscreen wiper mechanisms comprising a plurality of windscreen wipers.

The invention has been described in connection with the control of windscreen wipers on automobiles. However, it is not intended to be limited to this application and can in principle be applied to the wiper systems of other forms of transportation, such as aircraft, trains or seagoing vessels and to powered window wiper systems generally.

Claims

CLAIMS

1. A method of controlling the wipe frequency of a windscreen wiper (10), the method comprising determining a time interval between a first user input signal and a second user input signal and causing the windscreen wiper (10) to wipe at a frequency that is a function of the time interval.

2. A method as claimed in claim I, further comprising changing the frequency to cause the windscreen wiper (10) to wipe at a frequency that is a function of a time interval between a third user input signal and a fourth user input signal, the third and fourth user input signals being provided after the second user input signal.

3. A method as claimed in claim 1 or claim 2, whereby the user input signals are provided by a user operating a means for causing the windscreen wiper to perform a single wipe.

4. A method as claimed in claim 3, wherein the means for causing the windscreen wiper to perform a single wipe includes a lever arm for operating the windscreen wiper.

5. A method as claimed in any one of claims 1 to 4, wherein the frequency is substantially equal to the time interval.

6. A computer program product comprising at least one computer program software portion which, when executed in an execution environment, is operable to implement one or more of the steps of any one of claims 1 to 5.

7. A data storage medium having the or each computer software portion of claim 6 stored thereon.

8. A microcomputer (22) provided with a data storage medium as claimed in claim 7.

9. A windscreen wiper control system comprising a controller (16) arranged to receive user input signals, determine a time interval between received user input signals, and generate output signals for causing a wiper mechanism (10, 14) to provide a wipe frequency that is a function of the time interval.

10. A windscreen wiper control system as claimed in claim 9, wherein the controller (16) comprises a body control module for an automobile.

11. A windscreen wiper control system as claimed in claim 9 or claim 10, further comprising a switching arrangement (20) connected with the controller (16), the switching arrangement (20) being operable to have a relatively short duration contact position by which the user can cause the controller (16) to generate an output signal for causing the wiper mechanism (10, 14) to provide a single wipe, the controller (16) being arranged to treat each operation of the switching arrangement (20) to the relatively short duration contact position as a user input signal.

12. A windscreen wiper control system as claimed in any one of claims 9 to 11, wherein the controller (16) is arranged to determine the duration of a contact made by the operation of the switching arrangement (20) to the relatively short duration contact position and, when the duration is greater than a predetermined threshold, determine that the user input signal is a stop signal for the wiper mechanism (10, 14).

13. A windscreen wiper control system as claimed in any one of claims 9 to 12, wherein the wipe frequency is substantially equal to the time interval.

14. A windscreen wiper control system as claimed in any one of claims 9 to 13, connected with the wiper mechanism (10, 14).

15. An automobile comprising a windscreen wiper control system as claimed in any one of claims 9 to 14.

Amendments to the claims have been filed as follows

CLAIMS

1. A windscreen wiper control system comprising: a controller (16) arranged to receive user input signals, determine a time interval between received user input signals, and generate output signals for causing a wiper mechanism (10, 14) to provide a wipe frequency that is a function of the time interval; and a switching arrangement (20) connected with the controller (16), the switching arrangement (20) being operable to have a relatively short duration contact position by which the user can cause the controller (16) to generate an output signal for causing the wiper mechanism (10, 14) to provide a single wipe, wherein the controller (16) is arranged to treat each operation of the switching arrangement (20) to the relatively short duration contact position as a user input signal; and wherein the controller (16) is arranged to determine the duration of a contact made by the operation of the switching arrangement (20) to the relatively short duration contact position and, when the duration is greater than a predetermined threshold, determine that the user input signal is a stop signal for the wiper mechanism (10, 14).

2. A windscreen wiper control system as claimed in claim 1, wherein the controller (16) comprises a body control module for an automobile. ) ,

3. A windscreen wiper control system as claimed claim 1 or claim 2, wherein the wipe frequency is substantially equal to the time interval.

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4. A windscreen wiper control system as claimed in any one of claims 1 to 3, connected with the wiper mechanism (10, 14).

5. An automobile comprising a windscreen wiper control system as claimed in any one of claims 1 to 4.

6. A method of controlling the wipe frequency of a windscreen wiper (10), the method comprising the steps of: determining a time interval between a first user input signal and a second user input signal; generating output signals for causing a wiper mechanism (10, 14) to provide a wipe frequency that is a function of the time interval; and determining the duration of a contact made by each user input signal and, when the duration is greater than a predetermined threshold, determining that the user input signal is a stop signal for the wiper mechanism (10, 14).

7. A method as claimed in claim 6, further comprising changing the frequency to cause the windscreen wiper (10) to wipe at a frequency that is a function of a time interval between a third user input signal and a fourth user input signal, the third and fourth user input signals being provided after the second user input signal.

8. A method as claimed in claim 6 or claim 7, whereby the user input signals are provided by a user operating a means for causing the windscreen wiper to perform a single wipe.

9. A method as claimed in claim 8, wherein the means for causing the windscreen wiper to perform a single wipe includes a lever arm for operating the windscreen wiper.

10. A method as claimed in any one of claims 6 to 9, wherein the frequency is substantially equal to the time interval.