VEHICLE WINDSHIELD CLEANING SYSTEM
Apparatus and method for providing a heated cleaning fluid to a vehicle surface. The apparatus has an inlet port for receiving an amount of fluid; an outlet port for dispensing an amount of heated fluid; a heating element coil or tube covered with a plastic sheath that heats up fluid passing from the inlet to the outlet; and a control circuit for energizing at least a portion of the heating element with a voltage to heat the fluid passing from the inlet to the outlet. The apparatus also has expandable and compressible features and parts for protection against freezing.
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The present invention is a continuation in part of co-pending application Ser. No. 11/341,116 filed Jan. 27, 2006 which is a continuation in part of application Ser. No. 10/894,266, filed Jul. 19, 2004 (claiming priority from provisional application 60/551,571), which is a continuation in part of application Ser. No. 10/653,827 filed on Sep. 3, 2003, now U.S. Pat. No. 6,902,118 which is a continuation in part of U.S. Ser. No. 10/269,647 filed Oct. 11, 2002 (claiming priority from U.S. provisional application 60/415,552), now U.S. Pat. No. 6,851,624, all of which are incorporated herein by reference and from which priority is claimed.
FIELD OF THE INVENTIONThe present invention concerns a windshield cleaning system, and more particularly to a windshield cleaning system that heats cleaning fluid applied to the windshield.
BACKGROUND ARTU.S. Pat. No. 6,364,010 entitled “Device to Provide Heated Washer Fluid” to Richman et al. concerns an apparatus and method for improving the cleaning and deicing effectiveness of a washer fluid in a motor vehicle before spraying it against a windshield, headlamps, etc, and utilizes the heat from the engine coolant to elevate the temperature of the washer fluid. U.S. Pat. Nos. 5,957,384 and 6,032,324 also concern de-icing of a windshield.
SUMMARY OF THE INVENTIONThe invention concerns apparatus and method for providing a large amount of heated cleaning fluid to a vehicle surface. A system constructed with an exemplary embodiment of the invention has an inlet port for receiving an amount of fluid; an outlet port for dispensing an amount of heated fluid; a heating element that heats up fluid passing from the inlet to the outlet; and a control circuit for energizing at least a portion of the heating element with a voltage to heat the fluid passing from the inlet to the outlet.
In one exemplary embodiment, the system provides heated cleaning fluid to a vehicle surface and includes structure defining an inlet port for receiving an amount of fluid, an outlet port in fluid communication with the reservoir for dispensing an amount of heated fluid; and a metal heating coil for heating fluid that passes from the inlet to the outlet. The exemplary heater coil is covered by an elastic material for containing fluid in the event of a ruptured heating element caused by one or more freeze/thaw expansion and contraction cycles. A control circuit for energizing at least a portion of the metal heating coil with a voltage to heat the heating element and the fluid passing from the inlet to the outlet.
In accordance with another feature apparatus for providing a heated cleaning fluid to a motor vehicle surface includes a heating vessel having an interior and an inlet and outlet port. Heating fluid passes from the inlet to the outlet through the vessel. A controller has an energizing component for heating fluid passing from the inlet to the outlet, and an integral wiper motor control for actuating a motor vehicle surface wiper.
These and other objects advantages and features of the invention will become better understood from the following detailed description of one exemplary embodiment of the present invention which is described in conjunction with the accompanying drawings.
The drawings depict embodiments of the present invention that concern a washer control system 10 for use with a vehicle. In the disclosed exemplary embodiments of the invention, the control system 10 is used in conjunction with a windshield washer apparatus. The control system 10 includes a control circuit 14 that includes an electronic output drive signal circuit 20 and an input signal interpretation or conditioning circuit 16.
The input signal interpretation circuit 16 electronically interfaces with at least one temperature sensor 18. In one embodiment of the invention, the temperature sensor provides output signals related to the temperature of the washer fluid supplied to windshield spray nozzles on the vehicle. In one embodiment of the invention, the control system also includes an electronic output circuit that drives output power control for at least one heating element 30 that applies heat to the windshield washer fluid. The illustrated module output is a “low side” type drive, meaning the module activates and deactivates the heater element by controlling the electrical circuit path to ground. In accordance with an alternate control system, an electronic output coupled to a vehicular communication bus makes available data for system diagnostics. An alternate control system could have an output drive that is a “high side” type. Another alternate control system could have both “high side” and “low side” type drives working together as illustrated in
The control circuit 14 includes a programmable controller 14a that implements control algorithms for washer heater control output functions in response to vehicle input signals. As seen in the functional schematic of
The control system also includes an electronic output circuit 20 to control power coupled to at least one heater element 30. In the embodiment, the heater element 30 heats windshield washer fluid as the fluid passes through the heating element 30. A heating element that windshield washer fluid flows through, rather than a heating element that is submersed in the washer fluid, minimizes the formation and/or size of mineral deposits that could potentially clog application nozzles 37. The illustrated heating element 30 includes a length of stainless steel tubing with electrical connections 60, 62 (
As seen in the Figures the system has an inlet 32 and an outlet 34. The inlet receives washer fluid from a fluid reservoir 35 (
It is realized that the more resistive the material, the more resistance heating will occur, adding to the heating of fluid in the central reservoir. For example, a stainless steel central reservoir is more resistive and would provide more heating. The coiled heater tube 104 is constructed of stainless steel having a 5/16 inch diameter. The smaller diameter tube 104 is connected to an outlet 34 that routes heated fluid to nozzles or the like. This outer tube is coiled to an inside diameter of 1 11/16 inches.
In the illustrated embodiment, an energizing signal is applied to the ends of the series connected central reservoir 103 and heater tube 104 so that current passes through both the reservoir 103 and the tube 104. When the coiled heater tube 104 is made from stainless steel and the central reservoir 103 is made from copper, the stainless steel coiled heater tube 104 has a higher resistivity than the copper central reservoir 103 and therefore heats to a higher temperature more quickly, and acts as the primary heating source. In this example, the inner larger diameter reservoir is heated by some resistance heating but mainly by conduction heating from the coil.
The reservoir 103 and heater tube 104 in this embodiment are thermally coupled by an encapsulant 105 (see
The thermal coupling of potting encapsulant 105 between reservoir 103 and heater tube 104, along with the insulating feature already described provides additional advantages. In addition to being thermally conductive, another function of the encapsulant 105 is heat retention, so that sustained heating of the reservoir 103 occurs when electrical energy is not being applied to the heater tube 14. When surrounded by the previously mentioned insulation, the thermal energy of encapsulant 105 is maintained for extended periods of time. The thermal resistance of encapsulant 105 has an effect on how quickly the heater tube comes to temperature and how quickly the reservoir is heated through conduction. If an encapsulant is chosen with a lower thermal resistance, heat from the heater will quickly be dissipated into the potting and hence more quickly into the reservoir. This will give an operator of the system a longer initial heating time of the smaller volume of fluid contained in the tube, but faster heating of the larger volume of fluid contained in the reservoir. Conversely, an encapsulant could be chosen with a higher thermal resistance. The higher thermal resistance encapsulant will not dissipate heat from the heater as quickly as an encapsulant of low thermal resistance does thus allowing the heater to rise in temperature faster. This will provide an operator of the system with a shorter initial heating time of the smaller volume of fluid contained in the tube, but a slower heating of the larger volume of fluid contained in the reservoir. The thermal transfer properties of a commercially available encapsulant can be modified by additives or fillers resulting in a desirable thermal communication medium
The distance between the heater and the reservoir will have a similar effect on the heating of the heater tube and the reservoir. A lesser distance between the heater and the reservoir will have a similar heating effect as a lower thermal resistance encapsulant and a greater distance between the heater and the reservoir will have a similar heating effect as a higher thermal resistance encapsulant. In addition, the reservoir construction material and its thickness contribute to the thermal transfer characteristics.
The durometer rating of the thermoplastic rubber for the boot 320 is chosen to ensure that the boot has minimal expansion during normal usage of the washer system. This is because if a material is chosen that has significant expansion and contraction during normal washer usage, the nozzles will continue to weep fluid after the pump has been turned off as the system pressure is equalized to atmosphere. However, the selected material should not be so hard that it does not allow the material to flex when frozen liquid pushes on it. This could cause material fatigue and fracture in metallic components. The selected material should remain stiff during high temperature exposure and not take a set, and should remain pliable enough under low temperature exposure to adequately compensate for the expansion of liquid/solid matter.
Referring to
The programmable controller 14 constructed in accordance with the exemplary embodiment of the invention also implements control algorithms for washer heater control output functions in response to vehicle input signals. As washer fluid temperature changes due to ambient temperature changes, battery voltage changes, and the like, the amount of applied heat is increased or decreased in order to maintain a washer fluid at or near a target temperature.
Controller SchematicsThe system block diagram shown in
The block diagram shown in
An input 102 from the temperature sensor 18 in physical contact with the heating element 30 is directly related to washer fluid temperature. Washer fluid temperature is monitored by using a temperature sensor such as a thermistor, RTD, or the like. The washer fluid is monitored non-invasively by attaching the temperature sensor to the stainless steel tube of the heater. The temperature of the tube corresponds to the temperature of the fluid within the tube. Alternatively, the fluid temperature could be monitored invasively by placing a temperature sensor directly into the fluid through a threaded fitting or other suitable attachment method.
OperationThe controller receives a wake-up command signal from the Ignition input 100 (
-
- 1. The ignition voltage is greater than a first predetermined level and less than a second predetermined level.
- 2. The sensed Heater element temperature is less than a predetermined level.
Cleaning the windshield with warmed fluid can be accomplished by the following: - 1. Turning to
FIGS. 1 a, 45 and 46:- a. Application of ignition 42 will cause the unit to heat the volume of fluid. During the heating time an indicator LED 119 flashes. The LED is shown as part of the clean switch 113, but a skilled artisan could move the indicator external to the switch.
- b. When the indicator lamp is illuminated (not flashing), momentarily activating the clean switch 113, initiates a smart mode consisting of the energization of a washer pump and wiper motor.
- c. Output 115 activates the washer pump 117 to dispense fluid on the windshield. In the embodiment shown in
FIG. 45 , an external controller 123 activates a wiper motor 121 in response to a signal from the washer switch 113. One skilled in the art could have the same controller 14′ activate the wiper motor 121 and the washer pump 117 this embodiment is illustrated schematically inFIG. 46 . - d. Hot fluid will be sprayed on the windshield and the windshield wipers will cycle automatically, when the hot fluid reduces to a predetermined temperature, output 115 deactivates, thus completing the smart mode and washer spray/wiper cycling will halt. Momentarily pressing clean switch 113 during the smart mode will cancel the operation.
- 2. With ignition 42 applied and when indicator 119 is illuminated (not flashing) indicating warm fluid is available, the activation of the existing vehicle wash switch will dispense fluid for as long as the switch is closed for on-demand cleaning.
- 3. The activation of the existing vehicle wash switch will dispense fluid for as long as the switch is closed for on-demand cleaning regardless of fluid temperature.
An output driver 20 depicted in
Turning now to
When the controller provides a low output from the controller 14a at the output 122, the transistor 120 turns off and pulls an input 124 to a totem pole transistor combination 126 high. This signal turns on an uppermost of the two transistors of the totem pole combination to send an activation signal that turns on the two FETs 110, 112.
In one embodiment, a comparator 140 monitors current through the transistors 114, 116 (and by inference the transistors 110, 112) and deactivates the transistors in the event too high a current is sensed. A five volt signal that is supplied at an input 142 from a power supply (
In accordance with the exemplary embodiment of the invention a thermistor temperature sensor 18 is also coupled to the controller. A signal at a junction between the temperature sensor 18 and a resistor coupled to the five volt input 142 generates a signal at an input 150 related to the temperature of the heater 30.
Referring to
The exemplary control circuit includes a microcontroller running at an internal clock frequency of 4.0 Megahertz. In the exemplary embodiment, the microcontroller 14a selectively energizes the heating element based on a voltage applied to the control circuit. This voltage may be the battery voltage and/or the ignition voltage. When the ignition input voltage goes high, the control circuit will power up, come out of reset, and wait for a start delay time imposed by the controller to allow the vehicle's electrical system to become stable. After this start delay, the control circuit monitors the ignition voltage to determine if the ignition is above a minimum enable voltage. A temperature signal from the sensor 18 is also monitored to see if the temperature of the fluid is below a set point temperature. The output drive feedback signal is also monitored to ensure that the output is in the correct state. If all conditions are such that the output can be enabled, the output 122 to the transistor 120 is pulled low. This initiates fluid heating. Initially, the output drive is on 100% for a maximum on time or until the feedback temperature reading approaches a set point temperature. In one embodiment, a preset maximum on time is empirically derived to stay below the boiling point of the cleaning fluid. Subsequently the control will read the heating tube temperature and make a determination if power should be reapplied to the tube. If the sensed temperature is below the desired setpoint, the output will be re-enabled at a variable duty cycle so that the tube is heated to the setpoint goal temperature as quickly as possible without exceeding a maximum allowable overshoot temperature.
Normal operation consists of maintaining the fluid temperature at the desired setpoint temperature by varying the duty cycle at which voltage is applied across the tube. The output duty cycle changes based on how far the sensed temperature is below the set point temperature.
In the event of excessive current flow through the output, the output will automatically be disabled. In this event the signal at the output 146 from the comparator 140 (
In the event the operating voltage from the battery (and ignition) is too high or too low (≧16.5 and ≦8 volts respectively) the controller 14a disables the output for a timeout period. After the timeout period, if voltage conditions are within normal parameters, the controller again enables the output. The exemplary system also incorporates a soft turn-on and turn-off of the heating element. The soft turn-on and turn-off is accomplished by a slow ramp up or down of the PWM signal from the microprocessor 14a that drives the heating element. The ramping of power reduces the amount of flickering that can be observed from the vehicle headlights. It is recognized that the FET drivers could be run linearly (instead of pulse width modulated) to accomplish the soft turn-on and turn-off of the heating element. It is also recognized that the FET drivers could be run linearly to regulate the temperature of the heating element. It is further recognized that if the FET drivers are run linearly they will produce quantities of heat that will aid in the heating of fluid in the system.
Turning to
As also depicted in
Additional features of the invention adapted for use with a motor vehicle can be realized as described below. These embodiments have the same electrical configuration and operate in the same manner as the preferred embodiment.
One alternative embodiment of the invention uses a communications interface to transmit ambient temperature, battery voltage, washer switch activation status, washer pump use, engine running information, and other such information to the controller. Likewise, the controller could transmit task commands to the vehicle such as start wipers, pump washer fluid, controller status, and the like.
An alternate embodiment could include electronic input and/or output circuitry to interface with at least one ambient air temperature sensor 19 that provides output signals related to a sensed state of ambient air temperature.
Another embodiment of the invention could use engine coolant to heat the washer fluid prior to flowing through the heating element. This will reduce the amount of power required to heat the fluid to predetermined temperature using the heating element.
In the embodiment illustrated by
Another embodiment of the invention could use a time varying signal from the vehicle alternator to determine if the engine is running. This could be used in conjunction with the ignition input or as a stand-alone signal eliminating ignition input.
Another embodiment of the invention could use the washer pump 45a to regulate the temperature of the washer fluid. In this embodiment the system would control the washer pump 45a as well as the heating element. When the controller receives a request for washer use, the output driver would activate, heating the fluid with the heating element. When the washer fluid was at temperature the washer pump would be enabled. After the volume of heated fluid was used the pump would be disabled, and the fluid would again start heating to a predetermined level. After the fluid achieves the desired temperature level the pump would again be activated.
In one embodiment, the control circuit 14 includes an output 172 that controls the washer pump and separate output 174 that controls the wiper motor. This allows the control circuit to disable the wiper motor for a predetermined period of time after energizing the heating element and/or applying the heated fluid. For example, the control circuit could disable the wiper motor during the first heat cycle after initialization. This would allow for the heated fluid to have a more significant impact on surface contamination such as frost before the wipers are activated.
Another embodiment would have separate user input devices 178a, 178b for independent control of the washer pump and the wiper motor respectively. The user could then spray heated fluid on the windshield as required for cleaning independent of wiper action which tends to force heated fluid from the windshield and thins the remaining liquid film causing more rapid cooling of the liquid that is left on the windshield.
Another embodiment would have an auxiliary heating element on the inner copper reservoir 103. This would allow for more direct heating of the fluid contained in the reservoir as compared to the conduction heating of the fluid by the outer coil through the encapsulant material. This would also allow for the outer coil to be disabled when the system has been in a mode of operation that only sustains the temperature of the fluid. This would allow for a lower power heat source to be enabled over longer periods of time, compared to the high power very short duration pulses that are applied to the main heater coil. Decreasing the high current requirements would decrease the wear on the vehicle's electrical system. It is further realized that auxiliary heating could come from the FET transistors that drive the heating element. It is further realized that the auxiliary heating could come from a patterned heater such as a thermofoil heater or electro-thermal conductive flexible graphite, also known as vermiform graphite, such as those available from Minco Products, Inc., 7300 Commerce Lane, Minneapolis, Minn. 55432-3177 U.S.A. or EGC Enterprises Inc., 140 Parker Court, Chardon, Ohio 44024.
Similarly, another embodiment would have an auxiliary heating element 183 (
Another embodiment would have two different heat modes, the first having a higher power, the second a lower power. The two modes of operation could be used based on ambient temperature conditions. If, for example, it is below 40 degrees Fahrenheit where frost could be present on a vehicle windshield, the unit would use high power mode to heat fluid quickly to aid the operator in its removal. Alternately, if ambient temperature were say 40 degrees Fahrenheit or greater, a lower power mode would be used. This would allow for heating of fluid to aid in the cleaning of the windshield, but at a slower heating rate. This would decrease wear on the vehicle's electrical system when fast heating times are not required. The lower power is achieved by having a lower duty cycle on the heater drive. It is understood that the decision to switch from a power level to another power level could be accomplished with an external jumper or switch. This would provide the user with means for controlling the power applied to the heater. It is also understood that the external switch or jumper could cause the selection of other functions or characteristics.
Another embodiment could have a multiplicity of reservoir tanks connected in series or parallel combination. This would give increased available volume of heated fluid. Alternately, instead of having multiple reservoir tanks connected in one unit, multiple units could be connected together forming a system. Another alternate configuration would be the invention in conjunction with windshields that have self-heating capabilities, such as those with a translucent oxide coating enabling electrical current to flow from one end of the glass to the other creating heat due to the resistance of the coating.
Another embodiment could use a flow switch 200 (
An alternative embodiment could use two fluid temperature sensors, one at the heater element inlet and the other at the heater element outlet. When the heater is in operation and fluid is flowing, there should be a temperature differential across the heater element. That is, a fluid of a given temperature goes into the heater element, and warmed fluid exits the heater element. If the control used the washer motor voltage as an input to initiate a heating cycle, the two fluid temperature sensors could be used to determine that fluid flow exists. If there is a temperature differential, there would be flow. If there were a minimal or negligible temperature differential, a zero or low flow condition would be indicated. In the event of a low or zero flow condition, the heating element would be de-energized.
Another embodiment could have a diagnostic output that could be used for evaluating system performance and for diagnosing system faults. Operational parameters will be sent via communications such as serial communications using a proprietary bus or other standard bus protocol. A computer could be connected to the module using an appropriate interface cable to allow for reading and interpreting data. In addition to reading data for diagnostics, the invention could include communications and interface means to allow for programming of the microcontroller after the assembly of the device is complete. This would allow for software upgrades on units that have finished the manufacturing process.
Another embodiment could include control of the windshield wiper motor and washer pump. A separate switch input 43 (
Another embodiment could include control of the windshield wiper motor and washer pump. A switch input would activate an automatic cycle to dispense the fluid.
Another embodiment could include control of the windshield wiper motor and washer pump. A signal could be sent to an existing control module to initiate a washer and/or wiper sequence of operation as shown in
In another embodiment, the module would control delayed wiper functions and would also have a switch input for one-touch control of the wiper motor and washer pump for spraying of washer fluid in an automatic wash cycle with an automatic wash cycle consisting of a given number of washer pump cycles and given number of wiper motor excursions. It is understood that cycle counts and motor excursions could be substituted for given times.
Referring to
A heater element is comprised of first and second heater coils 500 and 501, which are brazed or otherwise attached to a reservoir 502. An insulator 503 surrounding the reservoir electrically isolates the coils 500, 501 from the reservoir 502. The reservoir 502 is enclosed on one end by cap 504, and on the other by freeze expansion elastic 505, which seals against the open end of a housing 506. The freeze expansion elastomer 505 is protected from damage by a protective cup 507, which is secured against the open end of housing 506. This provides a sealed chamber 508 to allow freeze expansion. A PCB 509 is electrically connected to the heater coils 500 and 501 by means of terminals 510 and 511, which are brazed onto the coils 500 and 501. Rivet fasteners 512 and 513 make a mechanical attachment between the terminals and the PCB.
A power FET component 514 is also attached to the PCB by means of the rivet 512. Battery positive and ground are applied to washer control system 10 through terminals 515 and 516, as shown in
Another embodiment shown in
Fluid chamber 464 holds a relatively small volume of fluid to minimize the heating time and allow heat from the heated fluid to then conduct through the wall of reservoir 462 and provide secondary heating of the fluid contained therein. The reservoir 462 is constructed from a plastic material, preferably containing glass fiber reinforcement for better conduction of heat. One suitable reservoir is constructed from glass reinforced High Density Polyethylene (HDPE). Another preferred construction of the reservoir 462 is to include a spiral feature that mates with heater wire 465 and functions to prohibit unintentional electrical shorting of adjacent coils.
As also depicted in
The reservoir 534 could have both ends open, using another metal end cap similar to that described for end cap 533 to make a fluid container. A power FET component 541 is soldered to the PCB 536 and then attached to the end cap 533 by means of fastener 555. The end cap 533 is constructed with a plurality of heat-sink projections 540 which project into the fluid chamber of the reservoir 534, allowing the power FET 541 to dissipate heat during operation. In the preferred embodiment, the heat-sink protrusions 540 are generally round in shape, but could be any shape that provides adequate surface area for heat-sinking performance, such as heat-sink protrusions 540′ shown in
The washer fluid contained inside the reservoir 534 acts to cool the heat-sink contact surface by means of thermal conduction through the copper material of end cap 533. Conversely, the dissipating heat from the power FET 541 thermally conducts heat into the washer fluid contained in reservoir 534 to provide added heat for cleaning, thereby increasing performance efficiency. An adapter 532, preferably also made from powdered metal copper alloy, can be fastened to the end cap 533 by any means well known in the art to provide a liquid tight seal with good electrical connection, including brazing, soldering or welding. The preferred method of fastening is by means of bonding into a one-piece part with the end cap 533 during sintering in the powdered metal process.
Referring to
Referring to
A connector shell 547, which is preferably made from 30% glass reinforced polybutylene-terephthalate (polyester PBT), such as G.E. Plastics Valox® 420, also accepts terminals 549, 550, 551, 552 and 553, which also pass through openings in the PCB 536 and are soldered in place to carry electrical signal commands to and from a control circuit such as the control circuit 14 (
Another source of heating for the fluid contained in the reservoir 534 is by means of heat radiated off the heated coils 530 and 531. The heat contained within the housing 548 thereby acts to warm the fluid contained in the reservoir 534, again increasing performance efficiency. Heat radiation can be enhanced by means of providing a reflective surface on the inside of housing 548. Black and other colored plastics would absorb heat, causing radiated heat from coils 530 and 531 to dissipate away from reservoir 534. A reflective surface, such as one that may be applied by means of vacuum deposition for instance, selectively plated to the walls of the housing 548 adjacent to the coils 530 and 531, would assist in keeping the radiated heat contained.
Battery positive and ground are applied to washer control system 10 through terminals 562 and 546, as shown in
Referring to
Referring to
The heater coils 530 and 531 could also have a multiplicity of notches introduced to the heater element surfaces to serve as stress concentration points for the purpose of directing the described expansion yield point to a specific location or locations. These notches could be very shallow details, approximately 0.005 inch in depth and 0.25 inches in length, located approximately 3 inches apart or the like. The sectional shape could be in the form of a “V” to accentuate the stress concentration. The introduction of such notches would serve to force ruptures to occur in a controlled location.
In a preferred embodiment, elastic material 670 is non-electrically conductive. Those properties provide a further function of elastic material 670 to electrically insulate heater coils 530 and 531 to prevent electrical shorting.
Referring now to
As previously disclosed, the heating element 685 is made from an electrically conductive metal, preferably type 304 stainless steel, but could be any material with similar high electrical resistivity properties capable of conducting electricity dependent on the size restraints of a particular control system application. Outer tube 686 is preferably made from an electrically non-conductive material with elastic properties that is expandable during freeze conditions, thereby preventing loss of both fluid and system functionality in the event of a break in a heating element. It is preferred that this material also exhibits characteristics of strength in order to maintain its general size and shape in withstanding typical vehicle washer system operating pressures, which could be as high as 50 psi. One adequate material for this purpose is nylon 12.
This embodiment of the heater coil also ensures that a desired system fluid flow can be maintained. System size restraints often dictate the necessary tubing size required for given performance, and those restraints in some embodiments can result in undesirable fluid pressure drop at the nozzles where the fluid is dispensed onto a surface as previously described. In the embodiment as shown in
A further embodiment allows for the determination of alcohol content of the washer fluid. If the alcohol to water ratio is know with some level of particularity, it is possible to alter the temperature threshold accordingly to achieve higher temperatures if there is a higher concentration of water. It is well known that alcohols used in washer fluid will boil at a temperature lower than that of water. Typically, the boiling points of said alcohols are around 150° F. while water is at 212° F. Raising the temperature threshold based on alcohol content may allow for improved efficiency in the removal of frost/ice and protein deposits. A further function of knowing the concentration of alcohol in the washer fluid is to provide a warning to the operator in the event of inadequate alcohol so that damage to the system will not occur due to freezing.
Referring to
A further embodiment the heater assembly is integrated into a wiper motor system. Referencing
A further embodiment of the heater and wiper motor assembly referenced in
Typically the motor shaft and worm gear are rotating at a rate approximately 50 times faster than the drive gear 840. This higher speed on the motor shaft can be used to drive an impeller 810 located in a pump housing 812 (
In the event washer arm 806 is not able to move due to mechanical issues or the blade being frozen to the windshield, the washer pump is prevented from dispensing fluid. If fluid was allowed to be dispensed it could adversely effect the driver's vision.
It is understood that the impeller could be mounted through a gear mechanism or flexible coupling that will change the orientation to the motor by an angle such as 90 degrees. It is further understood that if a different speed of rotation is needed for the impeller various standard means such as gear trains could be employed to achieve the desired rate of rotation. It is clear from the description that there is a cost advantage to be realized by the removal of a motor housing, an armature, a shaft, motor brushes, and other various components by using an existing motor to accomplish fluid pumping and wiper arm movement.
As depicted in
The pump portion of the assembly could contain sensing capabilities to determine if fluid was present in the pump chamber. If fluid was not present there would be less pressure at the outlet of the impeller chamber. This lower pressure could be sensed by a pressure sensor. The pressure sensor could be electronic or mechanical in construction. An electronic sensor 825 could be employed such as the piezoresistive silicon pressure sensor Model number 1451-050G-T from Measurement Specialties, Inc., Sensor Division and Consumer Sales, 1000 Lucas Way, Hampton Va. 23666. Alternately a mechanical construction could be a spring loaded plunger that held a magnet. With sufficient pressure the magnet would be pressed into proximity with a magnetic reed switch. A closed switch would result from a higher level of pressure indicating that there was fluid present. An open switch would result from lower pressure and indicate the need to add fluid. An alternate sensing mechanism could be a spring load vane to sense fluid flow. Similar configurations using magnets and reed switches previously described could be used with this mechanism. A further alternate fluid sensing method employs dielectric sensor 696. (
While the invention has been described with a degree of particularity, it is the intent that the invention includes all modifications and alterations from the disclosed design falling within the spirit or scope of the appended claims.
Claims
1. Apparatus for providing a heated cleaning fluid to a vehicle surface comprising:
- a) an inlet port for receiving an amount of fluid;
- b) an outlet port in fluid communication with the reservoir for dispensing an amount of heated fluid;
- c) a metal heater coil having an interior passageway for heating fluid that passes from the inlet to the outlet port through said passageway; wherein the heater coil is covered, at least in part by an elastic material for containing fluid in the event of a ruptured heating element caused by one or more freeze/thaw expansion and contraction cycles; and
- d) a control circuit for energizing at least a portion of the metal heating coil with a voltage to heat the heating element and the fluid passing from the inlet to the outlet.
2. The apparatus of claim 1 comprising:
- a) a fluid reservoir; and
- b) a plurality of heater coils covered with the elastic material through which fluid can flow wherein the heater coils are in thermal communication with the fluid reservoir.
3. The apparatus of claim 2 wherein the fluid reservoir is plastic and includes an expandable portion or portions that expands when fluid in the reservoir freezes to prevent damage to the reservoir.
4. The apparatus of claim 1 wherein the fluid reservoir is made of a material that flexes to expand during freezing.
5. The apparatus of claim 1 comprising a pump for pumping fluid through the heating metal heating coil.
6. The apparatus of claim 5 wherein the pump is comprised of a motor driving a single shaft.
7. The apparatus of claim 2 wherein thermal communication between the heater coils and the reservoir occurs through an encapsulant that is thermally conductive to transfer heat between the heater coils and the reservoir.
8. The apparatus of claim 7 wherein the encapsulant also acts to retain heat to provide sustained heating of the reservoir when electrical energy is not being applied.
9. The apparatus of claim 2 comprising a heat dissipating device that thermally conducts heat into the fluid contained in the reservoir to provide additional heating of the fluid therein.
10. The apparatus of claim 9 wherein the heat dissipating device comprises a power FET that is supplied with a variable gate voltage by the control circuit.
11. The apparatus of claim 10 wherein the control circuit divides a total power into a percentage of applied power to each of the heater coils and power FET as a means of controlling the speed of heating of each based on the demand for fast heating of fluid or heating of reserve fluid.
12. The apparatus of claim 2 wherein the two heater coils are isolated in order to prevent electrical shorting.
13. The apparatus of claim 12 wherein the heater coils are isolated by a plurality of plastic spacing members either connected integrally with the enclosure or attached as separate connecting parts of the heating element assembly.
14. The apparatus of claim 1 comprising two heater coils, each constructed from an electrically conductive tube connected in series and further comprising a reservoir connected to the heater coils by means of sealed fittings.
15. The apparatus of claim 14 wherein the sealed fittings are metal adapters that are coupled to the heater coil by means of flaring the tubing ends and securing in place with a threaded fastener.
16. The apparatus according to claim 1, wherein the heater coil has an outer surface spaced from the elastic material so that a heating fluid is routed both inside and outside the metal wall of said heater coil.
17. The apparatus of claim 16 wherein the elastic material comprises a larger diameter tube fixed loosely over the heater coil to capture fluid flowing along an outside surface of the heater coil.
18. The apparatus according to claim 17, wherein the larger diameter tube fixed loosely over the heater coil is an electrically non-conductive material with elastic properties that is expandable during freeze conditions, thereby preventing breakage and loss of fluid and system functionality.
19. The apparatus of claim 1 additionally comprising a probe for sensing alcohol content of fluid entering the inlet port.
20. A method for providing a heated cleaning fluid to a vehicle surface comprising:
- a) coupling an electrically conductive fluid carrying tube to a source of cleaning fluid;
- b) routing a cleaning fluid into an inlet port of the tube such that the fluid flows from the inlet to an outlet port of said tube;
- c) energizing said tube with a voltage to heat the fluid carrying tube and the fluid passing through the tube;
- d) directing the fluid from the outlet port to a nozzle for dispensing heated fluid against said surface; and
- e) covering at least a portion of the fluid carrying tube with an elastic material to contain fluid in the event of a ruptured tube caused by one or more freeze/thaw expansion and contraction cycles.
21. The method of claim 20 wherein said tube is energized with said voltage through a power switch FET by supplying a variable gate voltage to said FET to determine an amount of heat to be dissipated by said FET and wherein said FET is positioned proximate said tube such that said fluid in said tube acts as a heat sink for said power switch.
22. The method of claim 20 wherein about 150 ml of heated fluid is dispensed against said surface.
23. The method of claim 20 wherein the elastic material is a plastic tube having an inner diameter that is larger than an outside diameter of the conductive fluid carrying tube and further wherein fluid is routed with a region between the inner diameter of the plastic tube and the outer diameter of the conductive fluid carrying tube.
24-30. (canceled)
31. A method for providing a heated cleaning fluid to a vehicle surface comprising:
- a) covering an electrically conductive heating element with a flexible plastic tube having an elongated length sufficient to heat fluid passing through the flexible plastic tube;
- b) routing a cleaning fluid into an inlet port of the plastic tube such that the fluid flows from the inlet to an outlet port of said tube;
- c) energizing the heating element to heat the fluid passing through the tube;
- d) directing the fluid from the outlet port of the tube to a nozzle for dispensing heated fluid against said surface.
32. The method of claim 31 wherein the heating element is an elongated member having electrical contacts at either end which extends through the plastic tube.
33. The method of claim 31 wherein the heating element is an elongated metal tube through which fluid is routed so that fluid contacts and is heated by both and inside and outside of the metal tube.
34. A method for providing a heated cleaning fluid to a vehicle surface comprising:
- a) coupling a source of cleaning fluid to a heating vessel;
- b) routing a cleaning fluid into an inlet of the heating vessel such that the fluid flows from the inlet to an outlet of said vessel;
- c) heating fluid in the heating vessel as it passes from the inlet to the outlet;
- d) directing the fluid from the outlet to a nozzle for dispensing heated fluid against said vehicle surface; and
- e) activating a motor in response to the user activating a switch to dispense heated fluid from a nozzle and provide wiping action of wipers.
35. The method of claim 34 wherein a single motor is activated in response to the user activating a switch, said single motor pumping fluid into the heating vessel, dispensing heated fluid from a nozzle, and providing motive power for wiping action of wipers.
36. The method of claim 35 wherein an output from the single motor is coupled to a pump impeller by means of a clutch to allow separate control over pumping of fluid and wiper motion.
37. The method of claim 34 comprising coupling an output from a single motor to a wiper arm through a reducing gear to produce back and forth motion of one or more wiper blades.
38. The method of claim 34 wherein the vessel comprises a bent metal tube and the heating of fluid in said tube is performed by energizing the metal tube.
39. The method of claim 34 wherein pumping of fluid is prevented when the wiper arms/blade are not able to move.
Type: Application
Filed: Dec 29, 2009
Publication Date: Apr 29, 2010
Applicant: SBR Investments Company LLC (Birmingham, MI)
Inventors: David Shank (Hersey, MI), John Washeleski (Cadillac, MI), Peter Strom (Big Rapids, MI)
Application Number: 12/648,401
International Classification: B05B 17/04 (20060101); B05B 1/24 (20060101);