Apparatus and method for cleaning and de-icing

A windshield heated liquid spray assembly including a liquid heating assembly and a heated liquid spray assembly operative to spray the heated liquid onto a windshield, the liquid heating assembly including a liquid heating chamber, at least one heating element disposed in the liquid heating chamber and at least one heat dissipator in heat conduction contact with the at least one heating element, the at least one heat dissipator at least partially defining at least one liquid flow channel and being operative to transfer heat from the at least one heating element to the liquid flowing through the at least one liquid flow channel.

BACKGROUND OF THE INVENTION

The following publications are believed to represent the current state of the art:

SUMMARY OF THE INVENTION

The present invention seeks to provide improved apparatus and method for cleaning or de-icing vehicle elements.

There is thus provided in accordance with a preferred embodiment of the present invention a windshield heated liquid spray assembly including a liquid heating assembly and a heated liquid spray assembly operative to spray heated liquid onto a windshield, the liquid heating assembly including a liquid heating chamber, at least one heating element disposed in the liquid heating chamber and at least one heat dissipator in heat conduction contact with the at least one heating element, the at least one heat dissipator at least partially defining at least one liquid flow channel and being operative to transfer heat from the at least one heating element to the liquid flowing through the at least one liquid flow channel.

There is also provided in accordance with another preferred embodiment of the present invention a windshield heated liquid spray assembly including a liquid heating assembly and a heated liquid spray assembly operative to spray heated liquid onto a windshield, the liquid heating assembly including a liquid heating chamber, at least one heating element disposed in the liquid heating chamber and an electrical power supply connection to the at least one heating element, the electrical power supply connection including a meltable conductor portion in heat conductive contact with the liquid heating chamber and being operative to melt, and thus interrupt supply of electrical power to the at least one heating element in response to heating of liquid in the liquid heating chamber above a predetermined temperature.

There is further provided in accordance with yet another preferred embodiment of the present invention a windshield heated liquid spray assembly including a liquid heating assembly, a liquid temperature sensor operative to sense a temperature of liquid heated by the liquid heating assembly, a heated liquid spray assembly operative to spray the heated liquid onto a windshield and a controller operative to control operation of the spray assembly in accordance with the temperature sensed by the liquid temperature sensor, the controller providing at least one first spray instance beginning when the liquid temperature is at a first temperature and terminating when the liquid temperature is at a second temperature, below the first temperature, and at least one second spray instance terminating when the liquid temperature is at a third temperature, below the second temperature.

Preferably, the windshield heated liquid spray assembly also includes a temperature sensor operative to sense an ambient temperature outside of the liquid heating assembly. Additionally, the third temperature is determined by the controller based on the ambient temperature.

Additionally, the controller is operative to terminate the at least one first spray instance if the second temperature in not reached within a predetermined time. Additionally or alternatively, the controller is operative to terminate the at least one second spray instance if the third temperature in not reached within a predetermined time.

Preferably, the at least one second spray instance begins when the liquid temperature is at the first temperature.

Additionally, the liquid heating assembly also includes an electrical power supply connection to the at least one heating element, the electrical power supply connection including a meltable conductor portion in heat conductive contact with the liquid heating chamber and being operative to melt, and thus interrupt supply of electrical power to the at least one heating element in response to heating of liquid in the liquid heating chamber above a predetermined temperature.

Preferably, the windshield heated liquid spray assembly also includes at least one heat dissipator in heat conduction contact with the at least one heating element, the at least one heat dissipator at least partially defining at least one liquid flow channel and being operative to transfer heat from the at least one heating element to the liquid flowing through the at least one liquid flow channel.

Preferably, the windshield heated liquid spray assembly also includes a liquid temperature sensor operative to sense a temperature of liquid heated by the liquid heating assembly. Preferably, the at least one heat dissipator is configured and operative to enhance homogeneity of heating of the liquid in the liquid heating chamber, whereby the temperature sensed by the liquid temperature sensor is generally representative of the temperature of the liquid within the liquid heating chamber.

Additionally or alternatively, the at least one heat dissipator is configured to be non-uniform along at least one dimension of the liquid heating chamber. Preferably, the at least one heat dissipator is configured to extend along a longitudinal axis, which is intended to be aligned vertically and is non-uniform along the longitudinal axis, thereby to enhance homogeneity of heating of the liquid therealong.

Preferably, the at least one heat dissipator includes at least one aperture communicating with the at least one liquid flow channel.

Preferably, the at least one heat dissipator is located within the liquid heating chamber to define at least one fluid flow gap. Additionally, the at least one fluid flow gap causes fluid flow within the liquid heating chamber in multiple directions. Additionally or alternatively, the at least one heat dissipator is configured to extend along a longitudinal axis and wherein the fluid flow in multiple directions includes fluid flow in opposite longitudinal directions along the longitudinal axis. Preferably, the fluid flow in multiple directions provides enhanced homogeneity of temperatures of the liquid in the liquid heating chamber.

There is even further provided in accordance with still another preferred embodiment of the present invention a windshield heated liquid spray assembly including a liquid heating assembly and a heated liquid spray assembly operative to spray heated liquid onto a windshield, the liquid heating assembly including a liquid heating chamber, at least one heating element disposed in the liquid heating chamber and a liquid supply assembly coupled to the liquid heating chamber and including a valve operative to allow liquid flow into the liquid heating chamber and to impede backflow from the liquid heating chamber and at least one bypass conduit, user selectably operative to allow the backflow to bypass the valve.

There is still further provided in accordance with another preferred embodiment of the present invention a method for spraying heated liquid onto a windshield including providing a liquid heating assembly including a liquid heating chamber, at least one heating element disposed in the liquid heating chamber and at least one heat dissipator in heat conduction contact with the at least one heating element, the at least one heat dissipator at least partially defining at least one liquid flow channel, heating the at least one heating element, transferring heat from the at least one heating element to liquid flowing through the at least one liquid flow channel and spraying the liquid heated by the liquid heating assembly onto a windshield.

These is yet further provided in accordance with yet another preferred embodiment of the present invention a method for spraying heated liquid onto a windshield including providing a liquid heating assembly including a liquid temperature sensor, heating a liquid in the liquid heating assembly until a first spray cycle start temperature is sensed by the liquid temperature sensor, beginning at least one first spray instance when the first spray cycle start temperature is sensed by the liquid temperature sensor, terminating the first spray instance when a first spray cycle end temperature is sensed by the liquid temperature sensor; the first spray cycle end temperature being below the first spray cycle start temperature, subsequently beginning at least one second spray instance when a second spray cycle start temperature is sensed by the liquid temperature sensor and terminating the second spray instance when a second spray cycle end temperature is sensed by the liquid temperature sensor, the second spray cycle end temperature being below the first spray cycle end temperature.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference is now made toFIG. 1, which is a simplified illustration of a heated liquid discharge system suitable for use in a motor vehicle, constructed and operative in accordance with a preferred embodiment of the present invention. As seen inFIG. 1, a heated liquid discharge system100preferably includes a main assembly102, which provides liquid heating and includes electrical and liquid flow control functionalities. Main assembly102is preferably electrically connected via electrical cables (not shown) to a vehicle battery (not shown).

Main assembly102comprises a liquid heating chamber104communicating with a liquid inflow conduit (not shown) and a liquid outflow conduit (not shown). The liquid inflow conduit is operative to supply liquid, such as water, antifreeze or windshield cleaning liquid, from a vehicle liquid reservoir (not shown), having an associated vehicle pump (not shown), to the liquid heating chamber104. The liquid outflow conduit is operative to supply liquid to one or more sprayers (not shown), which may be located at one or more of the following vehicle locations: front vehicle windshield, back vehicle windshield, side vehicle windows in general and especially in locations providing viewing access to vehicle exterior mirrors, vehicle headlights, vehicle rear lights and vehicle exterior mirrors.

It is appreciated that the term “vehicle” as used in the context of the present patent application and in the claims can refer to any type of wheeled vehicle having windows, such as an automobile or a truck, as well as a boat or an airplane.

Main assembly102preferably includes a housing106defining a generally circular cylindrical liquid heating chamber accommodating volume108, in which is located liquid heating chamber104, in a major portion of which is disposed a liquid heating assembly110. Housing106also preferably defines a liquid inlet channel112, a liquid outlet channel114and an aperture for housing a heated liquid temperature sensor116, all communicating with liquid heating chamber accommodating volume108.

Reference is now made additionally toFIGS. 2,3A and3B, which illustrate details of the structure of liquid heating assembly110. As seen inFIG. 2, liquid heating assembly110preferably comprises a circular cylindrical outer sleeve120which defines liquid heating chamber104, and a base122, which defines a sealing ring retaining socket124, arranged to retain an insulating liquid sealing ring126(FIG. 1). A plurality of heating elements, preferably two in number, designated by reference numerals130and132, are located within sleeve120.

In accordance with a preferred embodiment of the present invention, a heat dissipator assembly140, including at least one heat dissipator, preferably encloses heating elements130and132. Heat dissipator assembly140includes heat dissipators142and144, defining respective liquid flow channels146and148, which are thermally and mechanically connected to heating elements130and132, preferably by soldering or any other suitable connection. Heat dissipator assembly140provides efficient heat transfer between heating elements130and132and liquid flowing through liquid flow channels146and148. Heat dissipators142and144preferably include multiple side apertures, designated by reference numerals150,152and154, to facilitate passage of liquid therethrough.

It is appreciated that liquid flow channels146and148provide efficient heating of the liquid contained therein.

As seen further inFIG. 2, outer sleeve120preferably includes multiple apertures, designated160,162and164, to enable liquid flow therethrough. It is appreciated that apertures150,152and154, as well as apertures160,162and164may be provided in any suitable quantity, location and shape to facilitate passage of liquid through outer sleeve120and heat dissipator assembly140. In a preferred embodiment of the present invention, a pair of each of apertures160,162and164are provided on opposite sides of a vertical axis thereof.

It is appreciated that apertures150,152and154, as well as apertures160,162and164are located and sized to provide increased homogeneity in the temperature of fluid located within liquid heating chamber104.

Liquid heating assembly110preferably also includes an electrical power supply connection165to base122.

As seen further inFIG. 1, heated liquid discharge system100also includes a liquid connector assembly166including a liquid inlet pathway portion168and a liquid outlet pathway portion170. Liquid connector assembly166preferably comprises an injection molded element which also defines a differential pressure bypass pathway portion172, which is controlled by a spring loaded one-way valve174and which permits liquid flow from liquid inlet pathway portion168to liquid outlet pathway portion170when the pressure differential thereacross reaches a predetermined threshold, typically 0.3-0.5 bar, which indicates the existence of a blockage in the liquid path through liquid heating chamber104.

A valve176is disposed in liquid inlet pathway portion168upstream of liquid heating chamber104. Value176preferably includes a partial sealing element, such as a ball177, which allows supply of liquid under pressure to the liquid heating chamber accommodating volume108but restricts backflow therethrough to a relatively slow rate. Alternatively, ball177of valve176may be obviated to allow backflow at a relatively faster rate than the backflow otherwise provided by valve176with ball177.

Liquid from the vehicle reservoir is supplied to liquid heating chamber accommodating volume108via liquid inlet pathway portion168and liquid inlet channel112and preferably enters liquid heating chamber104, defined by sleeve120, via apertures160,162and164formed in sleeve120.

The liquid is heated in liquid heating chamber104and the temperature of the liquid or the air overlying the liquid, depending on the liquid level, is sensed by temperature sensor116, preferably a sensor commercially available from EPCOS AG. Corporate Communications of Munich, Germany, identified by Catalog No. G560/50K/F2. Temperature sensor116preferably is mounted onto a printed circuit board178which is mounted within housing106and located outside of liquid heating chamber accommodating volume108.

Also mounted on printed circuit board178is control circuitry for operation of the main assembly102which is connected inter alia to temperature sensor116and the vehicle battery.

Reference is now made toFIGS. 4A and 4B, which are simplified illustrations of liquid flow within liquid heating chamber104.

In accordance with a preferred embodiment of the present invention, heat dissipators142and144are positioned relative to heating elements130and132to define liquid flow channels146and148. The heating elements130and132are preferably connected to the base122, preferably by soldering.

Heat dissipators142and144are positioned within outer sleeve120to define a fluid flow gap between a lower surface186of the heat dissipator assembly140and an upper surface188of base122. Additionally, walls of cylindrical outer sleeve120preferably extend beyond the top190of heat dissipators142and144, defining a fluid flow gap between the top190of heat dissipator assembly140and an upper surface192of the cylindrical outer sleeve120.

The fluid flow gaps described hereinabove, between lower surface186and upper surface188, and between top190and upper surface192, permit fluid flow in multiple directions within liquid heating chamber104as described hereinbelow.

As seen inFIG. 4A, heated fluid flows generally upwardly within heat dissipators142and144, as shown by arrow200, between lower surface186of heat dissipator assembly140and top190of heat dissipator assembly140. Upon reaching the area of liquid heating chamber104above heat dissipator assembly140, some of the fluid flows outside of the area above heat dissipator assembly140and is drawn into a downward flow, as shown by arrow202. Unheated fluid entering liquid heating chamber104through apertures160,162and164flows generally downwardly within liquid heating chamber104outside of heat dissipator assembly140, as shown by arrow204. Upon reaching the area of liquid heating chamber104below heat dissipator assembly140, some of the fluid flows inside of the area below heat dissipator assembly140and is drawn into an upward flow, as shown by arrow206.

The fluid flows indicated by arrows200,202,204and206in multiple directions are generated by differences in fluid temperature within liquid heating chamber104. Preferably, over time, the fluid flows indicated by arrows200,202,204and206produce increased uniformity of the temperature of the liquid in the liquid heating chamber104. The arrangement of heat dissipator assembly140within liquid heating chamber104, providing fluid flows in multiple directions, provides increased temperature uniformity and heating efficiency when compared to prior art heating units.

As seen further inFIG. 4A, liquid also flows through apertures150,152and154providing additional fluid flows shown by arrows208and210. It is appreciated that liquid entering heat dissipators142and144through apertures150,152and154, as shown by fluid flow indicated by arrow208, is drawn partially into an upward flow, by the existing flow within liquid flow channels146and148, and partially into a downward flow, when it is at a lower temperature than liquid within liquid flow channels146and148. Similarly, liquid exiting heat dissipators142and144through apertures150,152and154, as shown by fluid flow indicated by arrow210, is drawn partially into a downward flow, by the existing flow within liquid heating chamber104outside of liquid flow channels146and148, and partially into an upward flow, when it is at a higher temperature than liquid within liquid heating chamber104outside of liquid flow channels146and148.

As discussed hereinabove, the multiple fluid flows preferably provide for a generally homogenous temperature distribution within liquid heating chamber104and therefore measurement of the temperature of the liquid at the exit opening provides a generally representative indication of the average temperature of the liquid within the heating chamber104. Managing the temperature and flow controls of heated liquid discharge system100, done in accordance with measuring the temperature of the liquid at this point, provides enhanced homogeneity of the temperature of the heated liquid in liquid heating chamber104.

Specifically, heated liquid discharge system100, by providing enhanced homogeneity of liquid temperatures found therein, provides for an increased volume of fluid being sprayed during a spraying cycle whose duration is governed by the liquid temperature sensed by temperature sensor116. Accordingly, by providing enhanced homogeneity of liquid temperatures found therein, heated liquid discharge system100provides an increased amount of heat energy transferred to the windshield by the heated liquid during a given spray cycle.

It is appreciated that this feature of providing generally homogenous temperature distribution within liquid heating chamber104enables the heating system of the present invention to enhance heating of the windshield while conforming to the requirements and specifications of vehicle manufacturers, that define an upper limit to the liquid temperature allowed for heated spraying.

Reference is now made toFIGS. 5A and 5B, which are simplified sectional and top view illustrations of a liquid heating assembly suitable for use in the heated liquid discharge system ofFIG. 1in accordance with another preferred embodiment of the present invention.

As seen inFIG. 5A, a liquid heating assembly250preferably comprises a circular cylindrical outer sleeve252and a base254, which defines a sealing ring retaining socket256, arranged to retain an insulating liquid sealing ring (not shown). A plurality of heating elements, preferably two in number, designated by reference numerals258and260, are located within sleeve252.

In accordance with a preferred embodiment of the present invention, a heat dissipator assembly262, including at least one heat dissipator, preferably encloses heating elements258and260. Heat dissipator assembly262includes heat dissipators264and266, defining respective liquid flow channels268and270, which are thermally and mechanically connected to heating elements258and260, preferably by soldering or any other suitable connection. Heat dissipator assembly262provides efficient heat transfer between heating elements258and260and liquid flowing through liquid flow channels268and270. Heat dissipators264and266preferably include multiple side apertures, designated by reference numerals271,272and273, to facilitate passage of liquid therethrough.

It is appreciated that liquid flow channels268and270provide efficient heating of the liquid contained therein.

Outer sleeve252preferably includes multiple apertures, designated274,275and276, to enable liquid flow therethrough. It is appreciated that apertures274,275and276may be provided in any suitable quantity, location and shape to facilitate passage of liquid through outer sleeve252.

Liquid from the vehicle reservoir is supplied to liquid heating assembly250via a liquid inlet pathway portion (not shown) and a liquid inlet channel (not shown) and preferably enters liquid heating assembly250, defined by sleeve252, via apertures274,275and276formed in sleeve252.

The liquid is heated in liquid heating assembly250and the temperature of the liquid or the air overlying the liquid, depending on the liquid level, is sensed by a temperature sensor (not shown), preferably a sensor commercially available from EPCOS AG. Corporate Communications of Munich, Germany, identified by Catalog No. G560/50K/F2.

In accordance with a preferred embodiment of the present invention, heat dissipators264and266are positioned relative to heating elements258and260to define liquid flow channels268and270. The heating elements258and260are preferably connected to the base254, preferably by soldering.

Heat dissipators264and266are positioned within outer sleeve252to define a fluid flow gap between a lower surface280of the heat dissipator assembly262and an upper surface281of base254. Additionally, walls of cylindrical outer sleeve252preferably extend beyond the top282of heat dissipators264and266, defining a fluid flow gap between the top282of heat dissipator assembly262and an upper surface283of the cylindrical outer sleeve252.

The fluid flow gaps described hereinabove, between lower surface280and upper surface281, and between top282and upper surface283, permit fluid flow in multiple directions within liquid heating assembly250as discussed hereinbelow.

As seen inFIG. 5A, heat dissipators264and266preferably extend along a longitudinal axis286and are non-uniform, with varying thickness, along longitudinal axis286. Preferably, longitudinal axis286is intended to be aligned vertically within liquid heating assembly250. Preferably, the thickness of heat dissipators264and266is greatest in locations nearest to base254and decreases along longitudinal axis286proportionally to the distance from base254. It is appreciated that the provision of varying thickness provides a difference in heat transfer to fluid in regions located nearer to base254as compared with heat transfer to fluid in regions located more distant from base254and thus enhances homogeneity of liquid heating within liquid heating assembly250.

It is appreciated that the fluid flows of the liquid heating assembly250ofFIGS. 5A and 5Bare similar to those described hereinabove with reference toFIGS. 4A and 4B.

Reference is now made toFIGS. 6A and 6B, which are simplified sectional and top view illustrations of a liquid heating assembly suitable for use in the heated liquid discharge system ofFIG. 1in accordance with another preferred embodiment of the present invention.

As seen inFIG. 6A, a liquid heating assembly310preferably comprises a circular cylindrical outer sleeve320and a base322, which defines a sealing ring retaining socket324, arranged to retain an insulating liquid sealing ring (not shown). At least one heating element, designated by reference numeral330, is located within sleeve320.

In accordance with a preferred embodiment of the present invention, at least one heat dissipator340preferably encloses heating element330. Heat dissipator340is preferably thermally and mechanically connected to heating element330, preferably by soldering or any other suitable connection. Heat dissipator340provides for efficient heat transfer between heating element330and liquid flowing through liquid heating assembly310.

Outer sleeve320preferably includes multiple apertures, designated360,362and364, to enable liquid flow therethrough. It is appreciated that apertures360,362and364may be provided in any suitable quantity, location and shape to facilitate passage of liquid through outer sleeve320.

Liquid heating assembly310preferably also includes an electrical power supply connection365to base322.

Liquid from the vehicle reservoir is supplied to liquid heating assembly310via liquid inlet pathway portion (not shown) and liquid inlet channel (not shown) and preferably enters liquid heating assembly310, defined by the interior of sleeve320, via apertures360,362and364formed in outer sleeve320.

The liquid is heated in liquid heating assembly310and the temperature of the liquid or the air overlying the liquid, depending on the liquid level, is sensed by a temperature sensor (not shown), preferably a sensor commercially available from EPCOS AG. Corporate Communications of Munich, Germany, identified by Catalog No. G560/50K/F2.

As seen inFIG. 6A, heat dissipator340preferably comprises at least one plurality of fins370extending outwardly from heating element330along a longitudinal axis372defined by heating element330. In accordance with a preferred embodiment of the present invention, fins370are non-uniform, preferably of varying length and thickness, as described hereinbelow, along longitudinal axis372. Preferably, longitudinal axis372is intended to be aligned vertically within liquid heating assembly310. In a preferred embodiment of the present invention the at least one plurality of fins includes a first plurality of fins374of a first length extending outwardly from heating element330and a second plurality of fins376of a second length extending outwardly from heating element330, as seen inFIG. 6B.

As seen inFIG. 6A, preferably, the first plurality of fins374of a first length and the second plurality of fins376of as second length include a first group of fins380of a first surface area, a second group of fins382of a second surface area and a third group of fins384of a third surface area. Fins380, which are located nearer to base322than fins382and fins384, have a greater surface area than fins382and fins384, to provide additional surface area in contact with fluid flowing through liquid heating assembly310. Fins382, which are located nearer to base322than fins384, have a greater surface area than fins384, to provide additional surface area in contact with fluid flowing through liquid heating assembly310. It is appreciated that the provision of different groups of fins provides additional surface area in contact with fluid in regions located nearer to base322and enhances homogeneity of liquid heating within liquid heating assembly310.

It is appreciated that, while the illustrated embodiment includes first, second and third groups of fins, groups of fins may be provided in any suitable configuration, including two groups or more than three groups, each including different surface areas.

It is appreciated that the increased turbulence caused by fluid impinging on fins370provides increased heat transfer and homogeneity in the temperature of fluid flowing through liquid heating assembly310.

Reference is now made toFIGS. 7A and 7B, which are simplified sectional illustrations of an electrical power supply connection to the heated liquid discharge system ofFIG. 1in accordance with yet another preferred embodiment of the present invention, prior to overheating and upon overheating, respectively.

As seen inFIGS. 7A and 7B, a liquid heating assembly400preferably comprises a circular cylindrical outer sleeve402, defining a liquid heating chamber404. Sleeve402has a base414, which defines a sealing ring retaining socket416, arranged to retain an insulating liquid sealing ring (not shown). At least one heating element, designated by reference numeral420, is located within sleeve420. It is appreciated that even though only one heating element420is seen in the illustrated embodiment of FIGS.7A and7B, the electrical power supply connection ofFIGS. 7A and 7Bmay be used with liquid heating assemblies including any suitable configuration of heating elements.

In accordance with a preferred embodiment of the present invention, liquid heating assembly400includes an electrical power supply connection430, connected to base414, preferably by soldering. Electrical power supply connection430forms part of a circuit providing current to heating element420. An electric current input to heating element420is provided through an electrical connector point432. From there the current flows, preferably through a first end of heating element420, towards an opposite end of heating element420preferably connected to the metal body of heating element420, and from there to the base414. The current then flows through electrical power supply connection430to an electric contact434.

Electrical power supply connection430preferably includes a housing440, preferably a metal housing suitable for allowing electric current to flow through, an insulative layer442, preferably a plastic layer, and a meltable conductor portion444, preferably a solder portion, providing electrical connection between housing440and electric contact434.

As described hereinabove, under normal operating conditions, electric current flows through electrical power supply connection430from housing440, through meltable conductor portion444to electrical contact434.

Electrical power supply connection430provides a mechanism for disconnecting the current flow to the heating element in the event of overheating within the liquid heating chamber400, as described further hereinbelow.

Under normal operation, heating element420is activated only when liquid heating chamber400already contains a supply of liquid to be heated. In the event heating element420is activated with only a small quantity of liquid or no liquid in liquid heating chamber404, liquid heating chamber404is likely to rapidly reach a high temperature and overheat. The rise in temperature within liquid heating chamber404and heating element420would cause heating of base414which in turn would lead to a rise in the temperature in housing440.

When the temperature in housing440exceeds the melting temperature of the meltable conductor portion444of electrical power supply connection430, the meltable conductor portion444melts and drips out of housing440, as seen inFIG. 7B. The melting of meltable conductor portion444breaks the electrical circuit between housing440and the electrical contact434and interrupts supply of electrical power to the heating element420.

Electrical power supply connection430thus provides a one-time current flow termination and provides protection against damage to the vehicle resulting from overheating of the liquid heating chamber404caused by a heating system malfunction.

Reference is now made toFIG. 8, which is a simplified illustration of a heated liquid discharge system constructed and operative in accordance with another preferred embodiment of the present invention mounted in a motor vehicle, and toFIG. 9, which is a simplified timing diagram illustrating the operation of the system ofFIG. 8, in accordance with a preferred embodiment of the present invention.

As seen inFIG. 8, an otherwise conventional motor vehicle500is seen to incorporate a heated liquid discharge system502constructed and operative in accordance with a preferred embodiment of the present invention. The heated liquid discharge system preferably includes a main assembly504, which provides liquid heating as well as electrical and liquid flow control functionalities. Main assembly504is electrically connected via electrical cables506and507to a vehicle battery508.

A liquid inflow conduit510supplies liquid, such as water, antifreeze or windshield cleaning liquid, from a vehicle liquid reservoir512, having an associated vehicle pump514, to main assembly504. A liquid outflow conduit522supplies liquid to one or more sprayers524, which may be located at one or more of the following vehicle locations: front vehicle windshield, back vehicle windshield, side vehicle windows in general and especially in locations providing viewing access to vehicle exterior mirrors, vehicle headlights, vehicle rear lights and vehicle exterior mirrors.

A vehicle operator actuation switch530, typically located on the vehicle dashboard, is electrically coupled to main assembly504by a control conductor pair532. A pair of vehicle computer interface conductors534and536interconnect the main assembly504to the existing vehicle computer538. An ignition interface conductor540interconnects the main assembly504to the existing vehicle ignition switch. An external temperature sensor541is connected to main assembly504via conductor543.

The vehicle operator actuation switch530preferably provides a user input for actuating automatic sprinkling cycles described hereinbelow.

Liquid from reservoir512is supplied by vehicle pump514to main assembly504via liquid inlet conduit510and a liquid inlet pathway portion550. Liquid is supplied to sprayers524via a liquid outlet pathway portion554and liquid outflow conduit522.

Main assembly504preferably includes a liquid heating chamber560in communication with a temperature sensor570, preferably a sensor commercially available from EPCOS AG. Corporate Communications of Munich, Germany, identified by Catalog No. G560/50K/F2, and control circuitry for operation of the main assembly504which is connected inter alia to temperature sensor570and the vehicle battery.

As seen inFIG. 9, system actuation is preferably initiated by a user, such as a driver of a motor vehicle, depressing actuation switch530, typically located on the vehicle dashboard, as designated by reference numeral600. This actuation places the system into an automatic activation mode. The system is operative, in this mode, to operate pump514to execute a first spray cycle and a second spray cycle, designated by reference numerals602and604, respectively.

Upon entering automatic activation mode, heated liquid discharge system502is operative to provide a current to heating elements, heating the liquid contained in liquid heating chamber560, causing an increase in the temperature sensed by sensor570, as designated by reference numeral606.

When the temperature sensed by temperature sensor570reaches a first spray cycle start temperature, 75° C. in the illustrated example, as designated by reference numeral608, heated liquid discharge system502preferably operates pump514to execute first spray cycle602and discharge fluid through liquid outlet pathway portion554and liquid outflow conduit522to sprayers524. First spray cycle602preferably continues until the temperature sensed by sensor570reaches a first spray cycle end temperature, lower than the first spray cycle start temperature, 56° C. in the illustrated example, as designated by reference numeral610. In accordance with a preferred embodiment of the present invention, first spray cycle start temperature and first spray cycle end temperature are selected such that the duration of first spray cycle602is preferably approximately four seconds, during which time the temperature sensed by sensor570reaches the first spray cycle end temperature.

Upon termination of the first spray cycle602, the temperature sensed by sensor570starts to rise again due to the heating of the fluid contained in the liquid heating chamber560.

In accordance with a preferred embodiment of the present invention, heated liquid discharge system502is preferably operative to operate pump514to execute second spray cycle604when the temperature sensed by sensor570reaches a second spray cycle start temperature, 75° C. in the illustrated example, as designated by reference numeral612. It is appreciated that second spray cycle start temperature may be the same as the first spray cycle start temperature or may be different.

Second spray cycle604preferably continues until the temperature sensed by sensor570reaches a second spray cycle end temperature, lower than the first spray cycle end temperature and lower than the second spray cycle start temperature, such as 5° C. in the illustrated example, as designated by reference numeral614. In accordance with a preferred embodiment of the present invention, second spray cycle start temperature and second spray cycle end temperature are selected such that the duration of second spray cycle604preferably does not exceed eight seconds, during which time the temperature sensed by sensor570reaches the second spray cycle end temperature.

It is appreciated that heated liquid discharge system502may also be operative to end first spray cycle602based on a first spray cycle maximum duration, in the event that the first spray cycle end temperature is not reached within the maximum time duration. It is also appreciated that heated liquid discharge system502may also be operative to end second spray cycle604based on a second spray cycle maximum duration, in the event that the second spray cycle end temperature is not reached within the maximum time duration.

It is appreciated that the temperatures given are for illustrative purposes only, and that any suitable temperature ranges may be selected to determine the duration of the first and second spray cycles. It is appreciated that the time durations given are for illustrative purposes only, and that any duration may be selected as the maximum time allowed for the first and second spraying cycles602and604.

In accordance with another preferred embodiment of the present invention, heated liquid discharge system502may be operative to determine the second spray cycle end temperature as a function of an ambient temperature sensed by temperature sensor541. It is appreciated that determining the second spray cycle end temperature as a function of the ambient temperature provides an enhanced second spray cycle, particularly at very low ambient temperatures, such as below 0° C.

Reference is now made toFIGS. 10A and 10B, which are simplified sectional illustrations of a heated liquid discharge system suitable for use in a motor vehicle, constructed and operative in accordance with yet another preferred embodiment of the present invention, in two different operating modes.

As seen inFIGS. 10A and 10B, a heated liquid discharge system900, similar to heated liquid discharge system100ofFIG. 1, preferably includes a main assembly902, which provides liquid heating and includes electrical and liquid flow control functionalities. Main assembly902is preferably electrically connected via electrical cables (not shown) to a vehicle battery (not shown).

Main assembly902comprises a liquid heating chamber904communicating with a liquid inflow conduit (not shown) and a liquid outflow conduit (not shown). The liquid inflow conduit is operative to supply liquid, such as water, antifreeze or windshield cleaning liquid, from a vehicle liquid reservoir (not shown), having an associated vehicle pump (not shown), to the liquid heating chamber904. The liquid outflow conduit is operative to supply liquid to one or more sprayers (not shown), which may be located at one or more of the following vehicle locations: front vehicle windshield, back vehicle windshield, side vehicle windows in general and especially in locations providing viewing access to vehicle exterior mirrors, vehicle headlights, vehicle rear lights and vehicle exterior mirrors.

Main assembly902preferably includes a housing906defining a generally circular cylindrical liquid heating chamber accommodating volume908, in which is located liquid heating chamber904, in a major portion of which is disposed a liquid heating assembly910. Housing906also preferably defines a liquid inlet channel912, a liquid outlet channel914and an aperture for housing a heated liquid temperature sensor916, all communicating with liquid heating chamber accommodating volume908.

Liquid heating assembly910preferably comprises a circular cylindrical outer sleeve920, which defines liquid heating chamber904, and a base922, which defines a sealing ring retaining socket924, arranged to retain an insulating liquid sealing ring926. A plurality of heating elements, three in the illustrated embodiment, designated by reference numerals930,931and932, are located within sleeve920. It is appreciated that while the illustrated embodiment includes three heating elements, any suitable configuration of heating elements may be provided.

Outer sleeve920preferably includes multiple apertures, designated960and962, to enable liquid flow therethrough. It is appreciated that apertures960and962may be provided in any suitable quantity, location and shape to facilitate passage of liquid through outer sleeve920into liquid heating assembly910.

Liquid heating assembly910may also include an electrical power supply connection965electrically connected to base922.

As seen further inFIGS. 10A and 10B, heated liquid discharge system900also includes a liquid connector assembly966including a liquid inlet pathway portion968and a liquid outlet pathway portion970. Liquid connector assembly966preferably comprises an injection molded element which also defines a differential pressure bypass pathway portion972, which is controlled by a spring loaded one-way valve974and which permits liquid flow from liquid inlet pathway portion968to liquid outlet pathway portion970when the pressure differential thereacross reaches a predetermined threshold, typically 0.3-0.5 bar, which indicates the existence of a blockage in the liquid path through liquid heating chamber904.

A valve976is disposed in liquid inlet pathway portion968upstream of liquid heating chamber904.

Liquid from the vehicle reservoir is supplied to liquid heating chamber accommodating volume908via liquid inlet pathway portion968and liquid inlet channel912and preferably enters liquid heating chamber904, defined by sleeve920, via apertures960and962formed in sleeve920.

The liquid is heated in liquid heating chamber904and the temperature of the liquid or the air overlying the liquid, depending on the liquid level, is sensed by temperature sensor916, preferably a sensor commercially available from EPCOS AG. Corporate Communications of Munich, Germany, identified by Catalog No. G560/50K/F2. Temperature sensor916preferably is mounted onto a printed circuit board978which is mounted within housing906and located outside of liquid heating chamber accommodating volume908.

Mounted on printed circuit board978is control circuitry for operation of the main assembly902which is connected inter alia to temperature sensor916and the vehicle battery.

It is appreciated that valve976is similar in structure to valve176ofFIG. 1, including a ball980, except that valve976communicates with a conduit982which provides an alternative flow pathway between the sprayers and the reservoir. Heated liquid discharge system900thus provides two fluid flow passages for draining fluid from the sprayers to the reservoir upon the conclusion of spraying. As seen inFIG. 10A, an end986of conduit982extends beyond an outside surface of housing906.

Bi-directional valve1002preferably comprises a user positionable valve member1018. Bi-directional valve assembly1000further includes an inlet conduit1020for connecting heated liquid discharge system900to the vehicle reservoir (not shown).

In the operating orientation shown inFIG. 10A, valve member1018of bi-directional valve1002is located in the ‘ON’ position which permits flow into liquid heating chamber904bypassing ball980of valve976, as indicated by flows, designated by arrows1030,1032and1034, in addition to flow through ball980of valve976as indicated by flows, designated by arrows1040and1042. In the operating orientation ofFIG. 10A, heated liquid discharge system900supplies liquid under pressure to the liquid heating chamber904and allows backflow, as indicated by arrows1030,1032and1034, at a relatively fast rate.

In the operating orientation shown inFIG. 10B, valve member1018of bi-directional valve1002is located in the “OFF” position which permits flow into liquid heating chamber904through ball980of valve976, as indicated by arrows1040and1042. In the operating orientation ofFIG. 10B, valve976is functionally equivalent to valve176ofFIG. 1and allows backflow, as indicated by arrows1040and1042, at a relatively slow rate.

Heated liquid discharge system900thus provides user selectable backflow functionality without requiring valve976to be directly accessed after installation in a vehicle.

It is appreciated that bi-directional valve assembly1000may be obviated and a cap (not shown) placed over end986of conduit982. In this orientation heated liquid discharge system900allows supply of liquid under pressure to the liquid heating chamber904but impedes backflow therethrough, restricting backflow to a relatively slow rate.

It is appreciated that the systems of the present invention are suitable for inclusion both in new vehicles and for retrofitting into existing vehicles.

It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described hereinabove. Rather the scope of the present invention includes both combinations and subcombinations of the various features described hereinabove as well as modifications and variations thereof as would occur to a person of skill in the art upon reading the foregoing specification and which are not in the prior art.