EP2799610B1 - Washing machine with optimised program selection - Google Patents

Description

Field of the invention

The invention relates to a washing machine with a controller, which is designed to wash the laundry by means of several different washing programs, wherein the washing programs differ in their duration and in at least one washing parameters.

background

Washing machines normally provide the user with a number of different classes of washing programs. For example, there is a washing program for cooking linen, one for 60 ° wash, one for 40 ° wash, one for 40 ° sports wash and one for 30 ° wash, each with and without spin (centrifugation). Normally, each of these classes is assigned a washing program. These washing programs differ in one or more parameters, e.g. in the temperature or in the course of temperature and / or in the duration of individual program sections.

Furthermore, washing machines are known which allow the user to set the time for the start of the program or the end of the program. When the user sets the time to start the program, the controller of the device starts the washing program associated with the selected class at the set time. When the user sets the program end time, the controller calculates the start time from the expected duration of the program so that the program will finish at the specified time.

In DE 10 2007 062 016 a laundry care device is described with stored in the storage unit Operating programs with several operating program parameters. An adjusting element is used to set a setting value on the user side, as a result of which operating program parameters are adapted.

Presentation of the invention

The object of the present invention is to provide a washing machine of this type which is able to improve its operation with regard to a specific destination, for example, in that it consumes less energy or causes less costs.

This object is achieved by the washing machine according to claim 1.

Accordingly, the washing machine has a controller. This is designed to wash the laundry by means of several different washing programs. At least some of the washing programs differ in their duration, and the washing programs differ in at least one washing parameter. This washing parameter may be e.g. to the temperature, the temperature profile or the number and / or duration of individual program phases act.

Furthermore, the washing machine has an input device, which is configured to input the desired time for the program start or the program end of the wash program. The input device has the necessary hardware and / or software.

The control of the apparatus is basically configured to provide a washing program to be performed based on the inputted class, and to set the starting time based on the inputted time and to start the washing program to be performed at this starting time.

• Sie ist in der Lage, den Waschprogrammen eine vom jeweiligen Waschprogramm abhängige Zielgrösse zuzuordnen. Bei dieser Zielgrösse kann es sich z.B. um den Energieverbrauch, den Wasserverbrauch, die mit der Ausführung des Programms verbundenen Kosten, einen zu maximierenden "Ökoindex" errechnet aus dem Wasser- und Energieverbrauch oder einen anderen Wert handeln, der das jeweilige Waschprogramm charakterisiert.
• Basierend auf dem vom Benutzer eingegebenen Zeitpunkt bestimmt die Steuerung eine für die Ausführung des Waschprogramms zur Verfügung stehende Zeitdauer. Dabei handelt es sich insbesondere um die Zeitdauer zwischen dem Zeitpunkt der Benutzereingabe und dem vom Benutzer eingegebenen oder berechneten Zeitpunkt des Programmendes.
• Schliesslich ist die Steuerung dazu ausgestaltet, aus mehreren Waschprogrammen, welche unter die eingegebene Klasse fallen und in der zur Verfügung stehenden Zeitdauer ausführbar sind, dasjenige zu ermitteln, das die erwähnte Zielgrösse optimiert. Unter "Optimieren" ist dabei, je nach der Art der Zielgrösse, ein Minimieren oder ein Maximieren zu verstehen.

Furthermore, the controller is designed for the following measures:

• It is able to associate the washing programs with a target value dependent on the respective washing program. For example, this target may be energy consumption, water consumption, costs associated with running the program, an "eco-index" to be maximized from water and energy consumption, or any other value characterizing the particular wash program.
• Based on the user input time, the controller determines a time period available for executing the wash program. In particular, this is the time between the time of user input and the end of the program entered or calculated by the user.
• Finally, the controller is designed to determine from several washing programs, which fall under the entered class and executable in the available period of time, that which optimizes the mentioned target variable. Under "Optimize", depending on the type of target, minimization or maximization is to be understood.

In this way, the device is able, based on the specifications of the user (class of the program, time of program start or end) in the washing programs that meet these requirements to select the one that is optimal in terms of the target size. Thus, e.g. the one program that needs the least energy or water or whose eco-index is the highest.

In an advantageous embodiment, the target variable is dependent on the water consumption of the respective washing program, in particular (in the mathematical sense) a strictly monotonous function of water consumption. Specifically, the target size can be, for example, water consumption.

In another advantageous embodiment, the target variable is dependent on the power consumption of the respective washing program, in particular (in the mathematical sense) a strictly monotonous function of power consumption. Specifically, the target size can be, for example, equal to the power consumption or electricity costs.

For the controller to have a genuine choice between different wash programs, at least one of the user-selectable classes should have several different wash programs. These washing programs may differ gradually, e.g. in the period of an operating phase, which can be determined by the controller in a certain range (for example, 5 to 60 minutes) with virtually any desired fine resolution, or the washing programs can be discreetly distinguished, i. the controller may choose between some predetermined parameter values (e.g., 5, 15, 30, or 60 minutes).

The different washing programs in a class may differ, in particular, from their temperatures or temperature profiles, from their pause times between process phases, from amounts of water, from the number of individual operating phases and / or from their drum rotary movements.

Brief description of the drawings

• Fig. 1 eine Darstellung einiger relevanter Komponenten einer Waschmaschine,
• Fig. 2 ein Blockdiagramm der Steuerung.

Further embodiments, advantages and applications of the invention will become apparent from the dependent claims and from the following description with reference to FIGS. Showing:

• Fig. 1 a representation of some relevant components of a washing machine,
• Fig. 2 a block diagram of the controller.

Ways to carry out the invention Overview

In Fig. 1 some components of a washing machine are shown, which may be of interest in the present case. The device has a drum 1 for receiving the laundry. The drum 1 is driven by a drum drive 2 for rotation. Via a valve 4, the device is supplied via a mixing chamber 5 water, wherein 5 detergent can be mixed in the mixing chamber. The drum 1 is associated with a heater 6, with which the process water can be heated. A pump 7 serves to drain wastewater. These components are known in the art and need not be further described.

A controller 8 controls the components of the device. The controller 8 is connected to an input and output device 9, via which the user selects operating parameters of the washing machine and receives information about the status of the machine or a running washing program.

control

Fig. 2 shows details of the control 8. As mentioned, the controller 8 is connected to the input and output device 9. The controller 8 also receives signals from various sensors 10 of the device. These may in particular be temperature sensors for measuring the temperature of the process water, level sensors for measuring the water levels at at least one point of the device or other sensors. The controller 8 controls the heater 6, the drum drive 2, the various valves 4 of the device, the various pumps 7 of the device, and any other actuators.

The controller 8 has a microprocessor 12 which operates in accordance with a program stored in a memory 14. In the present embodiment, among other things, a list 15 of the available programs, the function of which is described in more detail below, is stored in the memory 14.

Further, the controller has a clock 16, via which the microprocessor receives the current time of day and possibly the day of the week.

programs

The controller 8 is configured to wash the laundry in the drum 1 according to one of several washing programs. Each washing program defines a set of parameters according to which the components of the appliance are controlled.

For example, each washing program determines which operating phases comprise the washing process (eg prewashing, main washing, rinsing, centrifuging), how long the operating phases last and how often they are repeated (eg, none, one or two pre-rinse phases), when fresh water is supplied, when Wastewater is pumped, which is to be achieved for temperatures or temperature profiles of the process water by operating the heater 6, as the drum drive 2 is to be operated in the different operating phases and how to control the other actuators of the device.

In the in Fig. 2 illustrated embodiment, the different washing programs that are available, stored in the table 15. Each program is assigned a unique program number (Prg.), A class (Kl.), A process duration (t), a target variable (Z) and several operating parameters (Params.).

The class K1 of a program describes eg the washing effect (strong, weak), the approximate temperature range as well as further basic parameters (eg with / without spin), which from the user's point of view are of importance. Programs of the same class are suitable for the same textiles and have essentially the same effects on the textiles. For example, there is a class which is displayed to the user as "40 ° spin wash sports wash" which includes multiple wash programs of varying durations. In the longer washing programs, slightly lower temperatures are used, and the laundry is treated longer, resulting in an approximately equally good washing effect. Another class, eg "cooking laundry", in turn comprises various programs that differ in their process duration. In the programs of this class, the temperature of the water is brought at least once to a relatively high value, but in the shorter programs, this high temperature is maintained for a relatively long time, while in the longer programs, the high temperature is maintained for less, but compensated Washed the laundry longer. Further examples of parameters in which the programs of a class may differ are described later.

• Kochwäsche
• Buntwäsche 60°
• Buntwäsche 40°
• Sportwäsche
• Wolle
• Handwäsche

Possible classes are eg:

• Cottons
• Coloreds 60 °
• Coloreds 40 °
• sportswear
• Wool
• Handwash

Other typical classes of washing programs of this type are known to those skilled in the art. Another distinguishing feature of the classes is, for example, the centrifugal (centrifugal) effect, so that a first class for coloreds 40 ° with intensive sling program, a second class for coloreds 40 ° with a light sling program and a third class for coloreds 40 ° without slings Can be provided, etc.

The target size Z of a program is a scalar quantity that should be optimized. This may, for example, be the energy consumption or the water consumption of the respective washing program. Further examples of the target size will also be described later. Per wash program is in the execution after Fig. 2 at least one such target Z is stored in the list 15. However, the target variable can also be calculated by the microprocessor 12 from the parameters of the washing program, in which case it need not be stored in the list 15.

The process duration t corresponds to the typical or expected duration of the respective washing program.

program selection

When the user wishes to perform a washing operation, he first selects at the input and output device 9 the class of washing program which he wishes to use. This is done by operating one or more input devices.

Furthermore, the user has the option of specifying the desired time for the start of the program or the end of the program. If it does not specify such a time, the controller 8 starts the program immediately. In this case, the automatic, optimized selection described below will be omitted, and instead a fixed standard washing program will be used from the user-selected class.

If the user indicates the time mentioned, he also has the option of using an input option of the controller, the automatic, optimized selection of the washing program of the controller 8 to leave. In this case, the program selection takes place in the following steps.

First, the controller 8 calculates the total time period D available for the washing process. For example, if the user performs the above-mentioned input at 23:30 clock and he gives the time for the end of the program as 8:30 clock, so the duration D = 9 hours.

If the user does not specify the time of the end of the program, but the start of the program, the controller 8 adds at this time the process time t, which is associated with the standard program of the selected class, so as to estimate the end of the program apparently desired by the user. For example, if again the input is at 11:30 pm and the user indicates the time of program start as 6:00, then the controller first determines the process time t of the default program associated with the selected class. If this is e.g. 75 minutes, the controller calculates from this the apparently desired time of program end as 7:15 clock or the duration D as 7 hours, 45 minutes.

After the controller 8 has calculated the time duration D, it determines in the list 15 all those washing programs whose process duration t is not greater than the time duration D and which belong to the class entered by the user.

If the user chooses to run from Fig. 2 For example, if the class 1 and the duration D = 500 minutes, then the programs 1 to 3 are determined in this way, while program 4 is omitted due to the excessive process time t.

From the programs thus determined, the controller 8 now determines the program which has the best target variable Z. If the target variable Z corresponds, for example, to the expected energy requirement in kilowatt hours, the controller 8 selects that washing program whose target variable Z has the lowest value.

In the above-mentioned example, the controller would determine the washing program 3 in this way, since this has the lowest energy requirement of 1,050 kWh of the programs 1 - 3 determined.

Having determined in this way the optimal washing program, the controller 8 calculates the start time for the effective program start to which the washing program should be started. This time controller 8 determines from the expected process duration t of the determined wash program such that the wash program ends within a certain tolerance period before the target time derived from the user input (i.e., the apparently desired end time of the program). The tolerance period is advantageously at most 20 minutes, in particular at most 10 minutes. The end time derived from the user input corresponds to the current time of user input plus the available time period D.

Then, the controller keeps the laundry treatment means of the device off until the mentioned start time is reached. Then the determined washing program is carried out so that it is ready shortly before or at the finish time.

outcomes

• Erwarteter Energieverbrauch des Waschprogramms. Anstelle des Energieverbrauchs selbst kann auch ein vom Energieverbrauch abhängiger Wert als Zielgrösse verwendet werden. Vorzugsweise handelt es sich um einen streng monoton vom Energieverbrauch abhängigen Wert, wie z.B. die erwarteten Stromkosten. Unterliegt das Gerät einem zeitabhängigen Stromtarif, der von der Tageszeit oder vom Wochentag abhängt, so kann die Steuerung die Kosten aus einem mit dem Waschprogramm abgespeicherten Energieverbrauchsprofil errechnen, wie gross die Stromkosten voraussichtlich sein werden, soweit der Steuerung die nötigen Angaben zur Struktur des Stromtarifs zugänglich sind.
• Erwarteter Wasserverbrauch des Waschprogramms. Anstelle des Wasserverbrauchs selbst kann auch ein vom Wasserverbrauch abhängiger Wert als Zielgrösse verwendet werden. Vorzugsweise handelt es sich um einen streng monoton vom Wasserverbrauch abhängigen Wert.
• Ein "Ökoindex", welcher z.B. aus einer Summe der skalierten Werte des Energieverbrauchs und des Wasserverbrauchs, jeweils mit negativem Vorzeichen, errechnet wird. In diesem Falle wird von den ermittelten Waschprogrammen dasjenige ausgewählt, das den grössten Ökoindex besitzt (d.h. denjenigen am nächsten bei 0).
• Die mechanische Wäschebelastung. Je nach Intensität der mechanischen Wäschebehandlung unterscheiden sich die einzelnen Programme in der Belastung, welcher sie die Wäsche aussetzen. So kann jedem Wäscheprogramm ein z.B. herstellerseitig ermittelter Wäschebelastungsindex zugeordnet werden, welcher minimiert werden soll. Beispielsweise kann der Wäschebelastungsindex eine Funktion der Zahl der zu erwartenden Trommeldrehungen (ohne Zentrifugieren) im Rahmen des Waschprogramms sein oder dieser Zahl entsprechen.
• Die Hygienewirkung. Je nach Temperaturverlauf im Waschprogramm kann jedem Waschprogramm eine Hygienewirkung zugeordnet werden. Waschprogramme mit Betriebsphasen bei hoher Temperatur (insbesondere ab 60°C) während einer gewissen Zeitspanne (insbesondere ab 15 Minuten, besonders ab 60 Minuten) weisen eine bessere Hygienewirkung auf und können entsprechend einen höheren Hygieneindex erhalten.

As already mentioned, the target value is a value which is to be optimized by the controller 8 by selecting the washing program to be carried out. This target variable is advantageously a scalar value, or another variable for which an order relation is defined. In particular, it may be one of the following sizes:

• Expected energy consumption of the wash program. Instead of the energy consumption itself, a value dependent on the energy consumption can also be used as the target variable. Preferably, it is a strictly monotonically dependent on energy consumption value, such as the expected electricity costs. If the device is subject to a time-based electricity tariff, which depends on the time of day or Depending on the day of the week, the controller can calculate the costs from a stored energy consumption profile with the washing program, how large the electricity costs are likely to be as far as the controller the necessary information on the structure of the electricity tariff are accessible.
• Expected water consumption of the wash program. Instead of the water consumption itself, a value dependent on the water consumption can also be used as a target variable. Preferably, it is a strictly monotone dependent on water consumption value.
• An "eco-index", which is calculated, for example, from a sum of the scaled values of energy consumption and water consumption, each with a negative sign. In this case, one of the identified wash programs selects the one that has the largest eco-index (ie closest to 0).
• The mechanical laundry load. Depending on the intensity of the mechanical laundry treatment, the individual programs differ in the load to which they suspend the laundry. For example, each laundry program can be assigned a laundry load index determined by the manufacturer, which is to be minimized. For example, the laundry load index may be a function of the number of drum rotations to be expected (without centrifuging) as part of the wash program or equal to that number.
• The hygiene effect. Depending on the temperature profile in the wash program, each hygiene program can be assigned a hygiene effect. Washing programs with operating phases at high temperature (especially from 60 ° C) for a certain period of time (especially from 15 minutes, especially from 60 minutes) have a better hygiene effect and can accordingly obtain a higher hygiene index.

The target quantity may also be a suitable function, eg a weighted sum, of two or more of these target values.

It is also conceivable to associate each target with several target sizes, e.g. the energy consumption, the water consumption, the mentioned organic index as well as the mentioned laundry load index. The input and output device 9 can be designed in this case so that it is possible for the user to select the target size to be optimized. The controller then selects that washing program from the determined washing programs, which is optimal with respect to the selected target variable.

program parameters

• Temperatur oder Temperaturverlauf: Die Waschprogramme einer Klasse können sich in ihrer Temperatur oder ihrem Temperaturverlauf unterscheiden. Beispielsweise können bei längeren Waschprogrammen einer Klasse geringere Temperaturen eingesetzt werden, oder die Betriebsphasen hoher Temperatur können bei längeren Waschprogrammen kürzer sein.
• Hygienewirkung: Verknüpft mit dem Temperaturverlauf ist die Hygienewirkung. So kann z.B. ein erstes Programm einer Klasse eine Behandlungsphase bei einer Temperatur von mindestens 60°, insbesondere während einer Zeitdauer von mindestens 15 Minuten, enthalten, während ein zweites Wäscheprogramm keine solche Behandlungsphase aufweist. Das erste Wäscheprogramm dauert länger als das Zweite, besitzt aber einen höheren Hygieneindex (vgl. oben) als das Zweite. Wird der Hygieneindex als Zielgrösse verwendet, so wird die Steuerung, sofern genügend Zeit vorhanden ist, das erste Waschprogramm wählen, ansonsten das Zweite.
• Wassermenge: Die Waschprogramme können sich in der verwendeten Prozesswassermenge in einzelnen Prozessschritten und/oder der insgesamt verbrauchten Prozesswassermenge unterscheiden. So kann z.B. ein Waschprogramm eine Vorspülphase enthalten, bei welcher die Wäsche mit einer relativ grossen Wassermenge während kurzer Zeit vorgespült wird, und bei einem anderen Waschprogramm kann eine deutlich kleinere Wassermenge eingesetzt werden, aber die Vorspülphase dauert dafür länger.
• Trommelbewegung: Die Waschprogramme einer Klasse können sich in ihrer Trommelbewegung unterscheiden. So kann in einem ersten Waschprogramm die Wäsche im Hauptwaschgang relativ intensiv bewegt werden, z.B. mit einer Drehzahl von 50 min^-1 und mit nur kurzen Pausen (wiederholend max. 10 Sekunden Pause gefolgt von 10 - 25 Sekunden Waschen), während in einem zweiten Waschprogramm die Wäsche im Hauptwaschgang langsamer und weniger oft bewegt wird, z.B. mit einer Drehzahl von 30 min^-1 und mit längeren Pausen (wiederholend 1 - 5 Minuten Pause gefolgt von 2 bis 10 Sekunden Waschen), und dafür dauert der Hauptwaschgang im zweiten Waschprogramm um ein Vielfaches länger als im Ersten. In diesem Falle hat das zweite Waschprogramm einen geringeren Energieverbrauch und belastet die Wäsche mechanisch weniger als das Erste, es dauert aber länger. Unterschiedliche Waschprogramme können auch unterschiedlich hohe Trommeldrehzahlen beim Zentrifugieren aufweisen.
• Trommelbeschleunigung: Hohe Beschleunigungen beim Anfahren der Trommel sind mit einem relativ hohen Energiebedarf verbunden, erlauben aber kürzere Prozessdauern. Somit können einer Klasse mehrere Waschprogramme zugeordnet sein, welche unterschiedliche Beschleunigungen der Trommelbewegung vorschreiben.

As noted, at least one of the user-selectable classes should have several different wash programs. In the following some parameters are listed in which these washing programs can differ.

• Temperature or temperature profile: The washing programs of a class may differ in their temperature or their temperature profile. For example, lower temperatures may be used for longer wash programs of a class, or the high temperature operating phases may be shorter for longer wash programs.
• Hygiene effect: Linked to the temperature profile is the hygiene effect. Thus, for example, a first program of a class may include a treatment phase at a temperature of at least 60 °, in particular for a period of at least 15 minutes, while a second program of laundry does not have such a treatment phase. The first wash program lasts longer than the second, but has a higher hygiene index (see above) than the second. If the hygiene index is used as the target variable, the controller will, if enough time is available, choose the first wash program, otherwise the second one.
• Amount of water: The washing programs may differ in the process water quantity used in individual process steps and / or the total amount of process water consumed. For example, a wash program may include a pre-rinse phase in which the laundry is pre-rinsed with a relatively large amount of water for a short time, and another wash program may use a significantly smaller amount of water, but the pre-rinse phase will take longer.
• Drum movement: The wash programs of a class may differ in their drum movement. Thus, in a first washing program the laundry, for example, at a speed of 50 min ^-1 and with only short breaks can be moved relative intensively in the main wash cycle (repetitive max 10 seconds rest followed by 10 -. 25 seconds washing), while in a second washing program the wash in the main wash is moved more slowly and less frequently, eg at a speed of 30 min ^-1 and with longer pauses (repeating 1 - 5 minutes break followed by 2 to 10 seconds washing), and the main wash cycle in the second wash program lasts for one Many times longer than in the first. In this case, the second washing program has a lower energy consumption and mechanically less burden on the laundry than the first, but it takes longer. Different washing programs can also have different numbers of drum speeds during centrifuging.
• Drum acceleration: High accelerations when starting the drum are associated with a relatively high energy requirement, but allow shorter process times. Thus, a class can be assigned several washing programs, which dictate different accelerations of the drum movement.

The programs of a class may also differ in several of the mentioned parameters.

Remarks

In the above-mentioned example, a plurality of predefined washing programs are stored in the list 15 for each class. However, it is also conceivable that instead of or in addition to the list 15 in the controller 8, a suitable algorithm is provided which calculates an optimal washing program from a plurality of conceivable washing programs of the respective class. For example, this algorithm may calculate the duration d of the main wash as a function of the available time duration D until the end of the program, e.g. d = D - k (where k is a constant taking into account the time required for the remaining phases of operation), with the proviso that d ranges from 15 to 240 minutes, and at the same time the total number of drum rotations in the main wash increasing length of d is reduced. If now, e.g. If the number of drum rotations is the target to be minimized, the controller will select the washing program in which the duration d has the largest possible value.

While preferred embodiments of the invention are described in the present application, it should be clearly understood that the invention is not limited to these and may be practiced otherwise within the scope of the following claims.

Claims (13)

1. Washing machine with
   a controller (8), which is adapted to wash the laundry by several different washing programs, wherein at least some of the washing programs differ in their duration and in at least one washing parameter,
   an input device (9), which is adapted to input at least one desired time for a program start or a program end and a class (Kl) of a washing program,
   wherein the controller (8) is adapted to provide a washing program to be performed based on the inputted class (Kl) and to determine a start time based on the inputted time and to start the washing program to be performed at this start time and
   to determine an available time duration (D) based on the time,
   characterized in that the controller (8) is further adapted
   to assign a target value (Z) to the washing programs depending on the particular washing program and
   to determine that washing program out of several washing programs, which falls in the inputted class (Cl) and can be performed in the available time duration (D), which optimizes the target value (Z).
2. Washing machine according to claim 1, wherein the target value (Z) depends on the water consumption of the washing program, in particular wherein the target value (Z) is the water consumption of the washing program.
3. Washing machine according to one of the preceding claims, wherein the target value (Z) depends on an electric power consumption of the washing program, in particular wherein the target value (Z) is the electric power consumption or the electric power costs of the washing program.
4. Washing machine according to claim 3, wherein the controller (8) is adapted to determine a time-dependent electricity rate and to calculate the target value (Z) depending on the time-dependent electricity rate.
5. Washing machine according to one of the preceding claims, wherein the target value (Z) depends on an intensity of a mechanic laundry treatment of the washing program.
6. Washing machine according to one of the preceding claims, wherein several washing programs with different temperatures or temperature profiles are included in at least one class (Kl).
7. Washing machine according to claim 6, wherein at least two washing programs are provided in at least one class (Kl), of which the one has a treatment phase at a temperature of at least 60° and the other one hasn't.
8. Washing machine according to one of the preceding claims, wherein several washing programs with different process water quantity are included in at least one class (Kl).
9. Washing machine according to one of the preceding claims, wherein several washing programs comprising several operating phases are included in at least one class (Kl), wherein the washing programs differ in the number of the operating phases.
10. Washing machine according to one of the preceding claims, wherein the washing machine has a drum (1) for receiving the laundry and a rotary drive (2) for the drum, wherein several washing programs are provided in at least one class (Kl), which prescribe different drum movements.
11. Washing machine according to claim 10, wherein several washing programs are provided in at least one class (Kl), which prescribe different accelerations of the drum movements.
12. Washing machine according to one of the preceding claims, wherein the controller (8) is adapted to derive a start time from an expected process duration (t) of the determined washing program and from a target time and to start the determined washing program at the start time such that the determined washing program ends in a tolerance time range of at most 20 minutes, in particular at most 10 minutes, before the target time, wherein the target time corresponds to an actual time plus the available time duration (D).
13. Washing machine according to one of the preceding claims, wherein the input device (9) is adapted to enable the user the selection of one out of several possible target values (Z), and wherein the controller (8) optimizes the selected target value (Z).

Images