DE102005055003A1 - Wind defogger`s power controlling method for window pane, involves determining actual temperature of window pane depending on environmental and vehicle parameters, and adjusting defogger power depending on actual and reference temperatures - Google Patents

Abstract

The method involves identifying hydrous coating on a window pane of a motor vehicle, and heating the pane by a wind defogger such that a preset reference temperature is reached after a preset time. An environmental parameter and a parameter of a vehicle are detected, and an actual temperature of the pane is determined depending on the environmental parameter and/or vehicle parameter. The power of the defogger is adjusted depending on the actual temperature and the reference temperature.

Description

The The invention relates to a method for controlling the disc heating in a motor vehicle according to the preamble of claim 1 and in particular for adjusting the power of the window heating to the windscreen to heat the vehicle.

by virtue of weather-related changes in The environment of a motor vehicle can in particular after a certain life of the motor vehicle, a coating on the windows form. When forming such a coating on a vehicle window such as. a moisture fitting or a layer of ice the disc quickly to a higher one Temperature be heated so that the coating is removed and the driver has unhindered visibility again. Especially true this on the windscreen too. For safety reasons, the disc temperature may however 70 ° C do not exceed otherwise there is a risk that the vehicle occupants burns move on. This maximum allowed Temperature of the disc of 70 ° C is required by law in every country. To the legal limits not to exceed even then if this is due to manufacturing tolerances, usually needs a "safety margin" at the temperature of 10 ° C be respected.

in the The state of the art is the electrical power for the windscreen heater reduced so far that the maximum disc temperature is not reached becomes. Alternatively, the duty cycle of the windscreen heater limited. This prevents overheating of the disc, And it is ensured that not unnecessarily consumes heating energy becomes.

Out EP 1 318 697 For example, there is known a method for controlling the activation of an electric heater for a window, wherein the electrical heater is activated in relation to a determination of a potential for window fogging based on an estimate of a dew point in the vicinity of the disk and a surface temperature of the disk. The potential for window fogging is determined such that the electrical heater is deactivated when the surface temperature of the disk exceeds the estimated dew point by at least a predefined temperature difference; and the predefined temperature difference is increased under specified operating conditions to provide anticipatory heating of the disk.

Of the Disadvantage of the prior art is that for controlling the heating power the washer heating temperature sensors mounted on the windscreen Need to become, the the actual temperature of the disc. A temperature sensor means additional Effort and thus increased Costs. Furthermore is such a temperature sensor visible on the windscreen and thus disturbing the appearance. Finally, temperature sensors can fail due to a technical defect and thus form one potential source of error.

task The present invention is a method for heating a Specify vehicle window, for example, to remove a fitting, in which the required heating power as required in dependence from the actual disk temperature is adjustable.

These Task is solved by the method according to claim 1. Preferred embodiments The invention are the subject of the dependent claims.

The solution according to the invention is based to calculate the temperature of the disk. The inventor has recognized that this with the sensors already existing in the vehicle on an accurate, reliable and sensitive species is possible even without its own temperature sensor, so that the temperature of the windscreen can be estimated accurately. Leave it due to the already available parameters the Adjust the windscreen heating exactly and according to the needs. The data on the the calculation of the temperature can be resorted to et al the outside temperature, the inside temperature, a solar sensor output, a fog sensor output, a rain sensor output signal, a light sensor output signal Vehicle speed sensor output signal, engine temperature and Engine speed, voltage, current and electrical power the windscreen heater, the windscreen resistors and the layer thickness of the windscreen heater. It can with some of these sizes Maps of measurements used become.

Based the available standing data can be decided if the covering on the disc is a moisture fitting or a layer of ice. Accordingly can be a preliminary Setting the heating power to be made. Due to the repeated review of this Parameter and thus the disk temperature, the heater can also Anticipating, ie before the actual appearance of the coating, be turned on and turned off just when the Topping to dissolve starts.

The inventive method for controlling the power of a window heater for at least one vehicle window in a motor vehicle with the steps: detecting a water-containing coating on the vehicle window and heating the pane by the pane heater, so that after a predetermined period of time a predetermined target temperature is reached at the disc is characterized by the steps detecting at least one environmental parameter and / or vehicle parameters of the vehicle, determining the actual temperature of the at least one disc in dependence on the at least one environmental parameter and / or vehicle parameter of the vehicle and adjusting the power of the window heating in dependence on the actual temperature and the target temperature.

• – der Umweltparameter hängt von wenigstens einer der Größen Außentemperatur, Intensität der Sonneneinstrahlung, Intensität des Tageslichts, Art des Niederschlages und Stärke der Luftbewegung ab;
• – der Fahrzeugparameter hängt von wenigstens einer der Größen Innentemperatur, Fahrzeuggeschwindigkeit, Motordrehzahl, Motortemperatur und Scheibenheizungsparameter ab;
• – der Scheibenheizungsparameter hängt von wenigstens einer der Größen Spannung an der Scheibenheizung, Strom durch die Scheibenheizung und Dicke der Scheibenheizung ab;
• – die Scheibentemperatur wird aus der Außentemperatur als Umweltparameter und der Innentemperatur als Fahrzeugparameter ermittelt;
• – das Aufheizen der Scheibe erfolgt durch eine transparente und leitfähige Schicht als Scheibenheizung;
• – das Aufheizen der Scheibe erfolgt in Abhängigkeit von der Motortemperatur außerdem durch ein Heizungsgebläse des Fahrzeugs;
• – die Leistung der Scheibenheizung wird in Abhängigkeit von der Fahrzeuggeschwindigkeit eingestellt;
• – die Leistung der Scheibenheizung wird in Abhängigkeit von einem Regensensorsignal eingestellt;
• – die Leistung der Scheibenheizung wird angehoben, wenn kein Außenlicht durch einen Lichtsensor erfasst wird;
• – die Leistung der Scheibenheizung wird derart begrenzt, dass die Stromstärke an keinem Ort der Scheibe einen vorgegebenen Wert überschreitet;
• – die Soll-Temperatur liegt um eine vorgegebene Differenztemperatur über der Taupunkttemperatur;
• – die Parameter werden in der Art einer Fuzzy-Logik miteinander verknüpft und aus gewertet.

In addition, preferred embodiments of the invention have one or more technically possible several of the following features:

• The environmental parameter depends on at least one of the parameters outside temperature, intensity of solar radiation, intensity of daylight, type of precipitation and strength of air movement;
• The vehicle parameter depends on at least one of indoor temperature, vehicle speed, engine speed, engine temperature and window heating parameters;
• The window heating parameter depends on at least one of the parameters: voltage on the window heating, flow through the window heating and thickness of the window heating;
• - the wheel temperature is determined from the outside temperature as an environmental parameter and the inside temperature as the vehicle parameter;
• - The heating of the disc is carried out by a transparent and conductive layer as a disk heater;
• - The heating of the disc is also carried out in dependence on the engine temperature by a heater fan of the vehicle;
• - The performance of the window heating is adjusted depending on the vehicle speed;
• - The performance of the disc heater is set in response to a rain sensor signal;
• - the performance of the windscreen heater is increased when no outside light is detected by a light sensor;
• - The performance of the disc heater is limited so that the current does not exceed a predetermined value at any location of the disc;
• - The target temperature is a predetermined difference temperature above the dew point temperature;
• - The parameters are linked and evaluated in the manner of a fuzzy logic.

The inventive solution et al the following advantages. After recognizing the starting temperature of the Windscreen and all relevant environmental conditions can be the actual Need for performance for the windscreen are calculated, with the minimum power being the one is necessary to keep the windscreen free, and the maximum power is the one that is legal to the law maximum values observed. It can single or multiple environmental conditions recorded and evaluated become. Thus, in the event of accidental activation of the windscreen heater the vehicle operating condition can be taken into account and into one Include energy balance calculation. It can be determined if the maximum permissible pulley temperature at all must be reached to guarantee a clear disk. With the method according to the invention let yourself Improve the charge balance of the battery, so that the battery life increased by reduced cyclization simultaneously. Besides, by the possibility the calculation of the really needed Heating power consumes less fuel, so less CO2 is emitted.

The Invention will be explained below with reference to the accompanying drawings.

1 shows a preferred embodiment of the method according to the invention.

in the following it is assumed that in the vehicle sensors for outside temperature, light and reflectivity the discs are provided. From the reflectivity of the discs may be due to contamination and especially wetting (rain) of the disc getting closed. The detection of light involves the recognition including the position of the sun Tunnel detection. About that In addition to these environmental parameters are usually as data Vehicle parameters such as internal temperature, vehicle speed, engine speed, Engine temperature and disk heating parameters.

Further It is assumed that the vehicle has a special window heater for example in the form of a glued or applied to the disc Heating foil or a metal coating features. In addition, the vehicles today usually have fans, the connected to a heater and an airflow to the windows can generate to heat them up.

In a vehicle, the outside temperature may be in the range of -30 ° C and + 40 ° C, the inside temperature in the range of -30 ° C and + 80 ° C. The window heater is therefore adjustable between 0 V and 40 V, the maximum electric power is up to 2,000 W. In comparison, the performance of a rear window heater in the size order of 400 W.

In 1 the sequence of an embodiment of the method according to the invention is shown.

As in the prior art, according to the invention first in step 1 checked if there is any surface on the disc. This may be a layer of ice located on the outside of the disk, or a moisture coating that usually deposits on the inside of the disk.

Around to remove a water - based coating from the disc, the Temperature of the disc brought to a higher target temperature. The calculation of the setpoint temperature will be explained below. The setpoint temperature is set in a control loop, the actual or instantaneous temperature of the disk flows as a disturbance in the Regulation.

For an accurate Regulation of the disc heater must be aware of the current temperature of the disc be. As the inventor has found out, but no own physical sensor are provided, but the temperature the disc can be calculated from already existing data in the vehicle become. For this, the existing sizes are quantitatively evaluated and logically linked. If necessary, plausibility parameters are taken into account. Among these can i.a. the engine temperature belong.

Checking if a covering is present or not, can with different sensors respectively. A fogging of the disc is caused by simultaneous (capacitive) Measuring the relative humidity and measuring the temperature detected. From both data results the current water vapor pressure and thus the dew point or the dew point temperature.

By further detection of the interior and the outside temperature can be close to the temperature of the disc and decide whether this over or is below the dew point temperature. If it is below the dew point temperature, so the disc is fogged with high probability. Lies the disk temperature is also below 0 ° C, so it can be assumed that the disc is iced.

Will be reflected in the flowchart 1 in step 2 recognized that no such coating is present, the process is terminated. Will against it in step 2 If it is recognized that a coating is present, the method jumps to step 3 , In step 3 environmental parameters are recorded. These are in particular, but not exclusively the outside temperature, the position of the sun, the light intensity and rain.

Subsequently, in the in 1 shown embodiment of the invention in step 4 Vehicle parameters recorded. These include indoor temperature, vehicle speed, engine speed, engine temperature, and disk heater parameters. The window heating parameters include, among other things, the voltage at the window heating, the flow through the window heating and the thickness of the window heating.

From these environmental and vehicle parameters will be in step 5 the actual temperature of the disc is calculated. In a very simple way of carrying out the method according to the invention, the window temperature is calculated from the interior temperature of the vehicle and the outside temperature. If, for example, the inside temperature is + 5 ° C and the outside temperature is -15 ° C, the temperature on the outside of the pane is below 0 ° C. In addition, if the relative humidity (outside) is high, the outside of the disc is probably iced.

In this case, in step 6 calculated a target temperature to which the disc must be heated in order to remove the water-containing coating from the disc. This target temperature is in particular by a predetermined differential temperature above the dew point temperature.

Before the glass heater is activated, in step 7 checks whether the setpoint temperature has already been reached. If this is the case because, for example, the heating has already been switched on, the process is ended. If not, the disc will be in step 8th heated. The heating process preferably takes place as a function of both the actual temperature and the setpoint temperature, and in particular as a function of the difference between the actual temperature and the setpoint temperature of the pane.

To improve the efficiency of this process, follow step 8th a return to step 2 , in which it is checked again whether a coating on the disc is present. If this coating has now disappeared, the procedure can be terminated. Otherwise, in step 3 and 4 recorded the new environmental and vehicle parameters and for a new calculation of the wheel temperature in step 5 used.

The embodiment of the method according to 1 Thus, it represents an iterative process, which is continued until the disc is free of any water-containing coating.

In a preferred embodiment of the invention, the heating power is throttled when influences are recognized that favor the heating of the disc. For example, the heating cable throttled when the solar sensor reports a strong sunlight.

If the engine temperature is at operating temperature, in addition to the actual windscreen heater a blower turned on that on the Disc is addressed. In this way, the power consumption throttle through the window heating and at the same time too strong Prevent heating of the disc, as the fan air to interior temperature is set.

If The rain sensor reports that it is raining, so it can be assumed that the pad on the disc is a moisture pad and no Ice. Consequently, here too, the heating power is shut down, so as not to heat the disc up to high temperatures and around the electrical energy available in the vehicle preferably efficient to use.

The Engine speed leaves recognize the maximum load capacity of the electrical supply. If the engine is started, idling and a deposit on the disc is detected, the engine should warm up and loaded become. In this case, the heating power will be at its maximum value set.

The Film of the disc heater shields electromagnetic radiation. For some Applications such as garage opener etc., which are operated from the interior of the vehicle, must therefore recesses be provided in the film. These lead to bottlenecks (hotspots) in the geometry of the heating layer, where the current density is greater than in Average of the slide is. Too high temperatures at these To risk bottlenecks just to get elsewhere on the heating layer To reach the target temperature faster, the heating power can be limited become. In maps, therefore, preferably the properties the disk heater is stored, such. the tension at the Window heating, the power through the window heating and the thickness the window heating. Based on these maps, the performance the heated windows are limited so that hotspots at the Disc can not occur.

If the speed sensor indicates a relatively high speed, so must of an additional Cooling the disc by heat convection be assumed. In this case, the heating power is increased slightly to this heat convection to compensate.

If about that out through the light sensor is reported that no outside light is detected, but at the same time the speed of the engine is increased, so has the security for the vehicle occupants have priority, and it is assumed that it is a ride during the night under bad visibility. In this case the heating power is increased, to ensure a quick release of the disc.

The Invention is not limited on the combination of two parameters for adjusting the heating power. It can to improve reliability the calculation of the current wheel temperature and prediction of the expected wheel temperature also more than two parameters with each other connected become. Thus, with corresponding values of the outside temperature and the inside temperature and also a low, cold engine temperature on icing of the windscreen closed. This becomes all the more probable, albeit one Idle is detected, indicating a "warm-up" of the engine before a ride. In contrast, a slow ride with cold engine and cold indoor / outdoor temperature recognized, it is concluded on the prevention of icing. When driving slowly with cold or warm engine and warm outside and relatively cold internal temperature is closed on fitting of the disc. In the first case, the maximum heating power is set, in the second case Case, the heating power is set to a lower value.

extra cooling down can by low outside / inside temperature, cold engine cooling water, speed (Air cooling the disc and wiper blades) included in the calculation.

The Linked invention on the one hand the parameters logically with each other, and on the other hand the parameters are evaluated quantitatively, taking into account those parameters resorted that is already measured by measurements for other purposes in the vehicle available. In other words, the windscreen temperature is calculated with the help of already installed sensors in the vehicle.

at The setting of the heating power will be the individual parameters preferably linked together in the manner of a fuzzy logic and evaluated. Furthermore or additionally can be up at some of these sizes Maps used which are based on measurements and manufacturer-side in the vehicle be stored.

The invention is not limited to the heating of vehicle windows and there in particular the windscreen. The regulation of the temperature of elements of the vehicle based on their calculated from environmental and vehicle parameters actual temperature can also on other heatable windows, such as rear windows, side windows, on the exterior mirror heating, the wiper blades behei tion and facilities such as fuel heating, a Waschdüsenheizung, a washing water heater, a heater for the crankcase breather, a wiper blade tray or other elements apply.

1

Detect of hydrous surface

2

Query: Covering available?

3

To capture of environmental parameters

4

To capture of vehicle parameters

5

Determine the actual temperature of the disk from parameters

6

Determine the target temperature of the disc from parameters

7

Query: Target temperature reached?

8th

Warm up the disc depending on of difference between actual and target temperature

Claims (13)

A method for controlling the power of a window heater for at least one vehicle window in a motor vehicle comprising the steps of: detecting ( 1 ) of a water-containing coating on the vehicle window and heating ( 8th ) of the disc through the disc heater, so that after a predetermined period of time a predetermined desired temperature is reached at the disc, characterized by the steps detecting ( 3 . 4 ) of at least one environmental parameter and / or vehicle parameter of the vehicle, determining ( 5 ) the actual temperature of the at least one disc in dependence on the at least one environmental parameter and / or vehicle parameter of the vehicle and setting ( 8th ) the power of the window heating as a function of the actual temperature and the target temperature. The method of claim 1, wherein the environmental parameter of at least one of the outdoor temperature, intensity the sunlight, intensity of daylight, type of precipitation and strength of air movement. Method according to claim 1 or 2, wherein the vehicle parameter of at least one of the internal temperature sizes, Vehicle speed, engine speed, engine temperature and disk heater parameters depends. The method of claim 3, wherein the slice heating parameter of at least one of the sizes tension on the window heating, electricity through the window heating and thickness the disc heater depends. Method according to one of the preceding claims, wherein the disk temperature from the outside temperature as an environmental parameter and the internal temperature is determined as a vehicle parameter. Method according to one of the preceding claims, wherein the heating of the disc by a transparent and conductive layer as a disk heater is done. The method of claim 6, wherein the heating the disc depending on from the engine temperature as well by a heating fan of the Vehicle takes place. Method according to one of the preceding claims, wherein the performance of the window heating depending on the vehicle speed raised becomes. Method according to one of the preceding claims, wherein the power of the window heating in response to a rain sensor signal is varied. Method according to one of the preceding claims, wherein the performance of the window heating is raised when no external light is detected by a light sensor. Method according to one of the preceding claims, wherein the performance of the window heating is limited so that the current strength at any location of the disc exceeds a predetermined value. Method according to one of the preceding claims, wherein the set temperature by a predetermined differential temperature above the dew point temperature lies. Method according to one of the preceding claims, wherein the parameters are linked in the manner of a fuzzy logic and evaluated.