Device for energy-saving defrosting of a windshield and a method for its operation

Abstract

Vehicle equipment, comprising: a glass windshield (10, 41); a wiper system (11) comprising a wiper blade (12, 13) which has a parking area (30, 72) on the windscreen (10, 41); a de-icer that selectively provides heat to the parking area (30, 72); a windshield temperature sensor (50) that detects a temperature of the windshield (10, 41) at the parking area (30, 72); a head-up display (33, 56) in the area of ​​the windshield (10, 41) that optically displays a temperature reading in response to the detected windshield temperature; an automatic control circuit designed to automatically deactivate the de-icer; and a manual control element designed to manually activate and deactivate the de-icer.

Description

BACKGROUND OF THE INVENTION

[0001] A system and method for controlling a defrosting unit for the windshield of a vehicle are already known from DE 10 2011 080 327 A1.

[0002] The present invention relates generally to the de-icing of windshields of road vehicles and, more particularly, to the reduction of energy consumption associated with heating the windshield at the parking position of a wiper blade, in particular by means of a vehicle device according to claim 1 and a method according to claim 16.

[0003] To improve the performance of windshield wiper blades in cold or frosty weather, a wiper de-icer has become a desirable feature. In particular, such a de-icer can provide heating to the windshield and wiper blades (which may be parked at a wiper parking position at a lower edge of the windshield). The applied heat can reduce or eliminate ice and snow buildup on a wiper blade, which affects performance or requires manual cleaning of the wiper blade by the driver.

[0004] While a wiper de-icer can be activated manually, it can be particularly beneficial when used in conjunction with remote vehicle starting, ensuring the vehicle is in drivable condition when the driver enters the vehicle. A typical de-icer system automatically shuts off after a predetermined period of time. While a manual switch is provided to deactivate the de-icer, a user may inadvertently forget to turn the system off after sufficient warm-up has occurred. Automatic turn-on times are typically chosen to keep the de-icer activated long enough to complete a complete de-icing under the majority of expected freezing conditions.

[0005] A commonly used heat source is an electrical resistance heating layer integrated into or applied to the windshield, powered by the vehicle's electrical system. Heat can also be obtained via a warm air (i.e., defroster) vent from a passenger compartment HVAC (heating, ventilation, and air conditioning) system. Depending on the vehicle type, the HVAC heat may be obtained from an electrical resistance heater (with a positive temperature coefficient) or as waste heat from an internal combustion engine. In either case, the defroster can consume significant amounts of battery charge.

[0006] Automatic deactivation of the de-icer after a predetermined period is lacking because the de-icing function is not adapted to the actual conditions. Thus, existing systems can lead to excessive battery discharge if the engine is left on for too long, or insufficient de-icing if the engine is turned off too early. In electric or hybrid electric vehicles, any excessive battery discharge becomes particularly problematic, as it can reduce the vehicle's electric range. PRESENTATION OF THE INVENTION

[0007] In one aspect of the invention, a vehicle device comprises a glass windshield and a wiper system including a wiper blade having a parking zone on the windshield. A de-icer selectably provides heat to the parking zone. A windshield temperature sensor detects a windshield temperature at the parking zone. A head-up display is mounted in the windshield region to visually display a temperature indicator in response to the detected windshield temperature. An automatic control circuit is configured to automatically deactivate the de-icer when it detects a defrosted condition in response to the detected windshield temperature. A manual control element is configured to manually activate and deactivate the de-icer. Excessive heating can thus be avoided based on windshield temperature feedback.In addition, the driver is reminded that the de-icer is active in a way that simultaneously provides information that allows the driver to self-assess vehicle conditions and make informed decisions about when to intervene in automatic operation. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows a windshield with a wiper system and a windshield heater by means of a window heater and by means of a warm air flow from an HVAC system. Fig. 2 is an interior view within a vehicle passenger compartment, including a windshield and a non-contact temperature sensor mounted in a rearview mirror. Fig. 3 shows a side view of the placement of one type of head-up display near the windshield. Fig. 4 is a block diagram of an electric vehicle with a de-icer system according to an embodiment of the invention. Fig. 5 is a state diagram for a de-icer control according to a preferred embodiment of the invention. Fig. 6 shows an embodiment with a head-up display that provides a visible display that overlaps with a wiper parking area. Fig. Figure 7 shows additional visual display options, including a text display and a display installed along a vertical side of the windshield. Fig. Figure 8 shows a preferred embodiment with head-up displays for windshield temperature and battery charge level. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0008] As now in Fig. 1, a glass windshield 10 has an associated wiper system 11 including wiper blades 12 and 13 on wiper arms 14 and 15, which are connected to a wiper motor 16 by a connection 17.

[0009] The wiper motor 16 can respond to a user interface 20 to activate the wiper system (e.g., in discontinuous or continuous mode).

[0010] The windshield 10 can be heated in one or more ways. For example, a resistive heating layer 21 is incorporated into the windshield 10, as is known in the art. The layer 21 is transparent and can extend over the entire windshield surface, as shown, or alternatively, can cover only a lower portion of the windshield 10 to provide heating at a wiper park area. One end of the layer 21 is connected to an electrical ground 22, and an opposite end is connected to a battery 23 via a controllable switch 24. The battery 23 is also connected to a ground 25. The switch 24 has a control input coupled to the user interface 24 so that battery power can be selectably coupled from the battery 23 to the resistive heating layer 21.The user interface 20 may include lever-mounted switches and / or instrument panel switches as are known in the art.

[0011] As in Fig. 2, the operator interface 20 may be located on an end surface of an instrument panel 26 near the steering wheel 27. A wiper parking zone 30 at a lower end of the windshield 10 is monitored by a non-contact temperature sensor 31. The sensor 31 may, for example, be mounted on a rearview mirror 32. The sensor 31 preferably comprises an infrared sensor positioned to have a field of view coincident with the parking zone 30. An example of a non-contact infrared device is the MLX90614 infrared thermometer from Melexis Microelectronic Integrated Systems in Novi, Michigan / USA.

[0012] The temperature sensor 31 may be connected to a control circuit (not shown) via the rearview mirror 32 by means of a wiring harness. The control circuit may comprise a microprocessor controller or other processor, which may be integrated into the user interface 20 or located in another electronic module within the vehicle. A head-up display 33 is located near the windshield 10 to visually display a temperature reading conveniently visible to the driver at a location near the wiper parking area 30, establishing an intuitive relationship between the display and the controlled function.The display is generated in response to the detected windshield temperature from sensor 31, and the temperature magnitude may be represented using text, color mapping, light intensity or brightness, a flashing icon with a variable flashing speed, a partially illuminated bar (similar to a progress bar), or other visual features. As shown in . Fig. As shown in Figure 2, the head-up display 33 may be incorporated into an A-pillar of a vehicle along an edge of the windshield 10. The display 33 may preferably comprise a multi-color LED, an array of LEDs, an LCD panel, or other display techniques.

[0013] As in Fig. 3, a head-up display may be used that relies on a reflection, by way of the windshield, of a display generated by a projector. Thus, a projector 36 mounted on the instrument panel cover 33 projects a temperature indication (and / or indications for other parameters), which may be reflected toward the driver, onto the windshield 10, as shown at 37. Preferably, the projector 36 and the windshield 10 are aligned such that the apparent location for the temperature indication as seen by the driver overlaps or is adjacent to the wiper parking zone. The projector 36 may include a multi-color LED for displaying warmer temperatures with red tones and cooler temperatures with blue tones, as commanded by a controller 38.

[0014] Fig. 4 shows a vehicle 40 having a windshield 41 with a wiper parking de-icer 42 for selectively providing heat to a wiper parking area under the control of a controller 43. The controller 43 may include, for example, a discrete control circuit, a programmable gate array, or a general-purpose microprocessor controller. The vehicle 40 is shown as an electric vehicle including a battery pack 44 and an electric drive 45. A battery control module (BCM) is used in conjunction with the battery pack 44, as is known in the art. The BCM 46 is coupled to the controller 43 to provide data regarding a state of charge of the battery pack to allow a visual indication of the state of charge to the driver. The driver can thus consider the effect on the battery state of charge when choosing whether to activate or deactivate the de-icer.

[0015] A remote keyless entry module (RKE module) 47 communicates with a remote transmitter 48, allowing a driver to initiate a remote start of the vehicle 40, as is known in the art. In the case of an electric vehicle, a "remote start" may include initiating heating or cooling of the passenger compartment and activating the windshield de-icer before the driver enters the vehicle. The RKE module 47 is thus coupled to the controller 43 to initiate de-icer operation when a remote start event occurs.

[0016] The controller 43 is coupled to a plurality of sensors for determining an icy or deiced (i.e., ice-free) condition of the windshield wiper parking area. The sensors include a windshield temperature sensor 50, an outside ambient air temperature sensor 51, an inside ambient air temperature sensor 52, and a solar load sensor 53. The windshield temperature sensor 50 preferably includes an infrared temperature sensor for monitoring the wiper parking area, as described above. In response to the various sensor inputs, the controller 43 uses a preprogrammed model to determine the most likely icy / deiced condition of the windshield glass. The controller 43 may be further configured to provide automatic control of deicer activation and deactivation using the determined condition.

[0017] The present invention additionally provides manual intervention via a user interface 55 and a heads-up display 56. The user interface 55 includes one or more manual controls configured to manually activate and / or deactivate the defrost heating function. The heads-up display 56 is located in the region of the windshield 41 (i.e., directly on, adjacent to, or visible by reflection from the windshield) to visually display a temperature indication in response to a detected windshield temperature, as described above. The heads-up display 56 may include a projector / generator installed to the side of the windshield 41, or alternatively, may include light-generating elements applied directly to the windshield 41, such as a printed LED film 57, which would also be controlled by the controller 43.

[0018] Controller 43 may preferably implement an empirically based model for determining whether frost conditions exist on windshield 41, which may be derived using various sensed temperatures, solar exposure, and other factors. A model that estimates heat flow within the air, glass, and surrounding materials to predict whether a defrosted condition would exist can be readily derived using known methods.

[0019] In addition to or instead of the temperature-based model, the presence of ice on the wiper blade or windshield (or even a wiper blade frozen in the parking area) can be determined based on the electrical response of the wiper system. For example, a current draw from the wiper motor under normal defrost conditions (e.g., a current curve) could be characterized in advance. By energizing the wiper motor and then monitoring an actual current, the normal defrost condition could be detected based on the extent to which the actual current matches the predetermined current.

[0020] In a simplified alternative embodiment, the additional temperature / sun exposure sensing and processing for predicting the defrost condition could be eliminated. Controller 43 could provide automatic deactivation based only on a predetermined duty cycle or delay for energizing the defroster. In such an embodiment, the driver may still obtain increased efficiency based on the head-up display displaying the windshield temperature 1) as a reminder that the defroster is active and 2) as a source of data useful in determining when the defroster can be deactivated.

[0021] Fig. 5 shows a preferred embodiment of a state diagram for a de-icer system of the invention. In an initial state 60, the de-icer is deactivated. In response to a start signal (e.g., starting the vehicle via a remote keyfob or a start switch in the vehicle), the system control circuit transitions to a state 61 where inputs (e.g., temperatures and solar exposure) are collected, and the controller performs a check to detect a de-iced condition. If a de-iced (i.e., ice-free) condition is detected, a transition back to state 60 occurs, and the de-icer remains deactivated. If no de-iced condition exists (i.e., there is a certain probability of icing), a transition to the enabled state 62 occurs, after which the de-icer is activated. In the enabled state 62, periodic checks for the de-iced condition can take place by transitioning back to state 61.The de-icer thus switches off (i.e., deactivates) once the defrosted state is reached. In state 62, the head-up display(s) are continuously updated to inform the driver of the windshield temperature and / or other parameters such as the battery charge level and the time remaining until the scheduled automatic de-icer deactivation. In the on state 62, a manual off event can be initiated by the driver using a manual control, which causes a transition back to the off state 60.

[0022] Upon entering the on-state 62, a predetermined on-time may be loaded into a countdown timer, which deactivates the de-icer after the on-time has elapsed. The decrementing of the timer occurs in response to periodically timed transitions from the on-state 62 to a time calculation state 63, which adjusts the remaining time (e.g., by decrementing the contents of the timer). If the timer has not yet expired (i.e., has not yet decremented to zero), a return to the on-state 62 occurs. Another adjustment of the remaining time would occur in response to a corresponding manual activation of a manual control by the driver in the on-state 62.In other words, a transition is made from the on state 62 to the time calculation state 63, where the content of the countdown timer is increased by a predetermined amount to extend the time remaining until automatic deactivation. The driver may thus have been informed of an impending automatic deactivation through the head-up display, and the driver responds by pressing the control to extend the activation of the de-icer, for example, based on visible icing of the wiper blade. If decrementing the timer in a state 63 results in zero (i.e., the timer expires), a transition is made to the off state 60, and the de-icer is deactivated.

[0023] Fig. 6-8 provide specific examples of a head-up display. In Fig. 6, a projector 70 (such as an array of color LED elements, with projection lenses if necessary) is arranged at a periphery of a windshield 71. The wiper parking area 72 on the windshield 71 is heated by a defroster (not shown). Light projected from the projector 70 onto the windshield 71 is reflected toward the driver, with an apparent position 73 overlapping or adjacent to the wiper parking area 72. A driver circuit 74 coupled to the LED array 70 receives appropriate control signals for varying color, brightness (intensity), and / or illumination at a commanded pulse repetition rate. The control signals implement a selected system that communicates windshield temperature data to the driver. For example, a below-freezing temperature may be represented by blue (e.g.,with different shades of blue for different temperature ranges) and a temperature above freezing using a red light (e.g., with different shades of red for different temperature ranges). As the timed de-icer activation approaches its expiration, a pulse repetition rate for the temperature data can be increased to signal the impending deactivation to the driver.

[0024] As in Fig. 7, a window head-up display 75 on a windshield 76 may include a text display for indicating de-icer status. A text display may be implemented, for example, using printed LED film. A driver circuit 77 is responsive to a controller (not shown) for configuring the display. The head-up display may further include an LED array 78 located in the area of ​​the windshield 76 by being installed along an edge of the windshield 76. An array of LEDs may be arranged in a rectilinear pattern with a variable number of LEDs illuminated starting from one end to display the desired information. The length of an illuminated bar and / or the color(s) shown along the bar may be used to convey temperature and / or time information. Low battery condition information.

[0025] In yet another, in Fig. 8, a windshield 80 may include a plurality of individual head-up displays 81 and 82 projected onto the windshield 80 to provide the driver with a coordinated display of windshield temperature, battery charge level, or other relevant information.

[0026] As shown in the above description, a head-up display can be constructed using various display technologies, such as printed LED films, LED projectors, and discrete LEDs or text displays. Displays can utilize text, color, illumination, and other intensity changes to convey temperature and other data. The invention provides improved defroster performance and reduced energy consumption by utilizing an infrared sensor to monitor the glass temperature in the windshield wiper parking area before, during, and after heating by the defroster. The measured glass temperature is used to generate a display for information to the driver and / or for use in an algorithm for inferring a defrosted condition and automatically controlling defroster on / off.The preferred embodiment provides coordination of automatic and manual processes, ensuring that de-icer power consumption only occurs when necessary. The use of an intuitive display in a conveniently visible location reduces the amount of attention required from the driver. The invention provides an effective reminder of system status, remaining activation time, and windshield temperature. The head-up display indicators can be configured to provide light over a wide area while allowing the driver to see through the display, thereby maintaining attention on the road while receiving head-up display information. The small size of the display elements and the unobtrusive locations allow more design freedom for the vehicle manufacturer to create an attractive product.In a preferred embodiment, the automatic control of the de-icer is adapted to accept manual interventions and provide the driver with useful information for making effective activation decisions based on important considerations including wiper performance and range of the electric vehicle.

Claims

[1] Vehicle device comprising: a glass windshield (10, 41); a wiper system (11) including a wiper blade (12, 13) having a parking area (30, 72) on the windshield (10, 41); a de-icer that selectively provides heat to the parking area (30, 72); a windshield temperature sensor (50) that detects a temperature of the windshield (10, 41) at the parking area (30, 72); a head-up display (33, 56) in the region of the windshield (10, 41) which visually displays a temperature indication in response to the detected windshield temperature; an automatic control circuit configured to automatically deactivate the de-icer; and a manual control element designed to manually activate and deactivate the de-icer. [2] The apparatus of claim 1, wherein the automatic control circuit deactivates the de-icer in response to detecting a de-iced condition based on the detected windshield temperature. [3] The apparatus of claim 1, wherein the automatic control circuit deactivates the de-icer after a predetermined duty cycle. [4] The apparatus of claim 1, wherein the windshield temperature sensor (50) comprises an infrared sensor mounted remotely from the windshield (10, 41) and having a field of view coincident with the parking area (30, 72). [5] Device according to claim 1, wherein the de-icer comprises a resistance heating layer (21) integrated with the glass windshield (10, 41). [6] The device according to claim 1, wherein the head-up display (33, 56) comprises a projector (36, 70) that projects the temperature display onto the windshield (10, 41). [7] The device according to claim 1, wherein the head-up display (33, 56) comprises a plurality of colored LED elements arranged on a periphery of the windshield (10, 41). [8] The apparatus of claim 1, wherein the temperature indicator has a color determined in response to the detected windshield temperature. [9] The apparatus of claim 1, wherein the control circuit is configured to automatically deactivate the de-icer after a predetermined duty cycle, and wherein the head-up display (33, 56) includes a time indicator responsive to a time remaining until the expiration of the predetermined duty cycle. [10] The apparatus of claim 9, wherein the control circuit is responsive to activation of the manual control element to extend the predetermined duty cycle. [11] The apparatus of claim 9, wherein the time display includes a pulsating display having a pulse frequency that varies in proportion to the remaining time. [12] The apparatus of claim 1, wherein the de-icer operates at a plurality of heating intensities and wherein the head-up display (33, 56) includes an intensity indicator. [13] The apparatus of claim 1, further comprising an electric vehicle drive (45) and a battery (44) providing electrical energy to the electric vehicle drive (45) and the de-icer; wherein the head-up display (33, 56) includes a battery charge level indicator. [14] The apparatus of claim 1, wherein the automatic control circuit deactivates the de-icer in response to detecting a de-iced condition based on the detected windshield temperature, an outside ambient temperature, an inside ambient temperature, and a solar load. [15] The apparatus of claim 14, wherein the automatic control circuit deactivates the de-icer in response to detecting a de-iced condition based on the detected windshield temperature and an electrical response of the wiper system (11). [16] A method for a vehicle windshield de-icer, comprising: contactless detection of a windshield temperature; activation of the de-icer in response to an icing condition; projecting a detected temperature display in the area of ​​the windshield (10, 41); automatically deactivating the de-icer in response to at least one of a period of time or detection of a de-iced condition using the sensed temperature; and Extending the period in response to manual activation; and deactivating the de-icer in response to manual deactivation.

Images