Method and household appliance for controlling humidity

Abstract

Household appliance (1) for cooking and/or baking food stuffs or bakery ware (2) comprising a heatable cavity (3) for placing the food stuffs or bakery ware (2), an access door (4) for accessing the cavity (3), a compartment (5) located exterior of said cavity (3), said compartment being in fluid communication with said cavity (3) by at least one duct (6), a control unit (10), at least one first sensor (8) located in the compartment (5) and being connected to the control unit (10), and wherein the at least one first sensor (8) is capable of measuring a first input value in said compartment (5), and at least one second sensor (9) capable of measuring a second input value, wherein said second input value is a temperature value wherein said control unit comprises a matrix of humidity index values, said matrix being deposited in said control unit (10), and wherein said control unit (10) is capable of correlating said input value of said at least one first sensor (8) to a humidity index value from said matrix.

Claims

1. Household appliance for cooking and/or baking food stuffs or bakery ware comprising: a heatable cavity for food stuffs or bakery ware, an access door for accessing the cavity, a compartment located exterior of said cavity, said compartment being in fluid communication with said cavity by at least one duct, a control unit, at least one first sensor located in the compartment and being connected to the control unit, and wherein the at least one first sensor is capable of measuring a first input value in said compartment, and at least one second sensor capable of measuring a second input value, wherein said second input value is a temperature value, wherein said control unit comprises a matrix of humidity index values, wherein said control unit is adapted to correlate said first input value and said second input value to a humidity index value from said matrix throughout a steam cooking operation of a cooking process and to compare said humidity index value to a set humidity value throughout the steam cooking operation, said control unit being further adapted to determine and/or generate an output signal for controlling a humidity controlling means based on said comparison throughout the steam cooking operation.

2. Household appliance according to claim 1, wherein said at least one first sensor capable of measuring a first input value is a humidity sensor, and wherein said first input value is a humidity value within said compartment.

3. Household appliance according to claim 1, wherein said compartment comprises at least one mixing element for mixing and/or diluting a fluid from the cavity with air.

4. Household appliance according to claim 3, wherein said at least one mixing element is located in fluidic connection with said compartment and/or wherein said at least one mixing element is a radial fan or a tangential fan.

5. Household appliance according to claim 3, wherein said fluid is fresh and/or cold air, steam, vapor and/or a mixture thereof.

6. Household appliance according to claim 1, wherein said at least one first sensor and said at least one second sensor are connected to the control unit.

7. Household appliance according to claim 1, said at least one first sensor being located at a position exposed to temperatures of about 100 C. or less and/or exposed to relative humidity of about 100% or less during operation of said household appliance.

8. Household appliance according to claim 1, wherein said compartment is a cooling channel and/or a cooling chamber, and/or wherein said compartment is located on top of said cavity.

9. Household appliance according to claim 1, wherein the at least one duct is in fluid communication with the compartment and said cavity: through at least one outlet opening of said cavity for exhaustion of air and/or vapor and/or steam or a mixture thereof, out of the cavity into said compartment, and/or through at least one inlet opening of said cavity for influx of air and/or vapor and/or steam or a mixture thereof from said compartment into the cavity, wherein, said at least one duct can be opened or closed by at least one valve.

10. Household appliance according to claim 9, wherein the at least one outlet opening is arranged in an upper area of the cavity, and/or wherein the inlet opening is arranged in a lower bottom area of the cavity.

11. Household appliance according to claim 1, wherein the at least one second sensor is located in the cavity in a wall thereof, or is located in the compartment, or wherein one second sensor is located in the cavity wall and a further second sensor is located in the compartment.

12. Household appliance according to claim 1, comprising at least one further first sensor located in the cavity, said at least one further first sensor being connected to the control unit, wherein the at least one further first sensor is capable of measuring a humidity value within said cavity as an input value of said at least one further first sensor.

13. Household appliance according to claim 1, wherein the steam cooking operation comprises: a boost cycle wherein the heatable cavity is heated to a set temperature and taken to the set humidity value, and a cooking cycle wherein the set temperature and the set humidity value are maintained.

14. Household appliance according to claim 1, wherein the cooking process further includes a non-steam cooking operation.

15. Method for controlling humidity in a cavity of a household appliance, comprising at least the following steps: a) adjusting a set humidity value for a boost cycle and/or a cooking cycle and/or a de-steaming cycle of steam cooking operation of a cooking process by a user input; b) humidity control carried out throughout the steam cooking operation, said step of humidity control comprising at least the following steps: i) measuring a first input value by the at least one first sensor and measuring a second input value by the at least one second sensor; ii) correlating said first input value and said second input value to a humidity index value from a matrix, wherein said matrix comprises such humidity index value, said matrix being deposited in a control unit of the household appliance, said correlation comprising comparing said first input value and/or said second input value to the matrix; iii) comparing said humidity index value from step ii) to a set humidity value for a boost cycle and/or a cooking cycle and/or a de-steaming cycle of a cooking process from step a); iv) determining and/or generating a humidity output signal for controlling a humidity controlling means based on the comparison from step iii); and v) controlling said humidity controlling means and generating a humidity value in the cavity according to the humidity output signal.

16. An appliance comprising a heatable cavity for cooking food stuffs, a compartment located exterior of said cavity and being in fluid communication therewith via a duct that can be opened and closed via a valve, a first sensor for measuring a first input value comprising at least one of a first temperature value and a first humidity value measured at a location within said compartment where the temperature is about or less than 100 C. during operation of said appliance, a second sensor for measuring a second input value comprising a second temperature value within said cavity, said compartment comprising a fan for diluting with ambient air cooking fumes entering said compartment from said cavity via said duct and for exhausting a mixture of said cooking fumes and said ambient air from within said compartment out of the appliance, a humidity controlling means adapted to introduce steam into said cavity, a control unit in operative communication with each of said first sensor, said second sensor, said valve and said humidity controlling means, said control unit being adapted to continuously receive first input value data from said first sensor and second temperature value data from said second sensor and to continuously correlate said first and second input values with a corresponding humidity index value from a lookup table, said control unit being further adapted to continuously compare said continuously correlated humidity index value to a set humidity value to thereby regulate the humidity in said cavity in order to target said humidity index value to said set humidity value by: actuating said valve to facilitate expulsion of humidity-laden cooking fumes from said cavity through said duct; and operating said humidity generating means to introduce steam into said cavity.

17. The appliance according to claim 16, said set humidity value being either user-selected or stored in a predetermined cooking program.

18. The appliance according to claim 16, said compartment being located above said cavity and said duct being in communication with said cavity via an outlet opening in an upper wall of said cavity, said humidity controlling means being in communication with said cavity via an inlet opening arranged in a lower area of said cavity.

Description

(1) The present invention will be described in further detail with reference to the drawings from which further features, embodiments and advantages may be taken, and in which

(2) FIG. 1 illustrates a schematic figure showing a cross sectional view through a cavity of a household appliance showing a first inventive embodiment;

(3) FIG. 2 illustrates a detailed perspective top view of a cavity and compartment of a household appliance showing the first inventive embodiment;

(4) FIG. 3 illustrates an exemplary matrix for use in connection with the present invention;

(5) FIG. 4 illustrates an exemplary diagram of humidity index vales over time during a cooking operation according to the inventive method; and

(6) FIG. 5 illustrates an exemplary diagram depicting various combinations of humidity values for boost and cooking cycle.

(7) FIG. 1 illustrates a schematic figure showing a cross sectional view through a cavity 3 of a household appliance 1 showing a first inventive embodiment, here a steam-cooking oven 1.

(8) In the following detailed description of the present invention, reference is made particularly to said household appliance being a steam-cooking oven 1 capable of a steaming function by introducing water or steam into the cooking cavity to create special food cooking conditions.

(9) However, it will be appreciated that what is described and claimed here equally applies to any other type of household appliances for cooking and/or baking food stuffs or bakery ware, particularly a household appliance, more particularly an oven, without such steam function and/or operated without applying such steam function, with the slight modification that during a boost cycle, a humidity build-up is achieved by moisture from the foodstuff itself. Therefore, it is to be understood that what is described and claimed here according to a particular cooking oven with steam function, particularly, also is applicablewith only slight modifications known to a person skilled in the art and described hereinto any other type of household appliances for cooking and/or baking foodstuffs or bakery ware, particularly without such steam function and/or without operating such steam function, and is considered herein within the scope of the present invention.

(10) A household appliance 1 for cooking and/or baking food stuffs or bakery ware 2 according to the present invention comprises a heatable cavity 3 for placing the food stuffs or bakery ware 2, which may be placed on a grid or tray 21, an access door 4 for accessing the cavity 3, a compartment 5 located exterior of said cavity 3, said compartment being in fluid communication with said cavity 3 by at least one duct 6, at least one first sensor 8 capable of measuring a first input value, wherein said first input value is a humidity value or a pressure value, and at least one second sensor 9 capable of measuring a second input value, wherein said second input value is a temperature value. Such household appliance 1 may further comprise a central fan 23, for example, as a convection fan, which may be located in or adjacent to a cavity rear wall 22. Such central fan 23 may comprise a fan shield 24.

(11) In such household appliance 1 the at least one first sensor 8 is located in the compartment 5. The at least one first sensor 8 capable of measuring a first input value, is a humidity sensor 8, and said first input value is a humidity value within said compartment 5, preferably a value of relative humidity. Said compartment 5 comprises at least one mixing element 7, here a fan element 7 in form of a main cooling fan, for mixing and/or diluting a fluid, here fumes, from the cavity 3 with air, particularly with a significantly exceeding quantity of air.

(12) Said compartment 5 here in the form of a cooling chamber, and particularly the cochlea of said main cooling fan 7 comprises said at least one fan element 7 for ventilating a fluid from and/or into said cavity 3. Particularly, said main cooling fan 7 ventilates a cooling airflow out of the appliance, and sucks in fresh ambient air for cooling the appliance. Through the duct 6, fumes are escaping the cavity into the cooling chamber 5.

(13) Said at least one first sensor 8 and said at least one second sensor 9 are connected to a here not shown control unit 10, capable of controlling the input of air and/or steam into and the output of fumes from said cavity 3, preferably by closing and/or opening of said at least one duct 6, for example by a valve, and/or operating the mixing element 7, and/or controlling a humidity controlling means 14, here a humidity generating means in the form of a steam generator 14.

(14) As may be seen best from FIG. 1 said compartment 5 being a cooling chamber, and preferably a part of the cochlea 20 of the fan 7, and said at least one first sensor 8 is located at a position exposed to temperatures of about 100 C. or less and exposed to relative humidity of about 100% or less during operation of said household appliance 1.

(15) The compartment 5 is a cooling channel and/or a cooling chamber, preferably an oven-cooling channel and said compartment 5 is located exterior of said cavity 3, particularly said compartment 5 is located on top of said cavity 3.

(16) The at least one duct 6 is in fluid communication with the compartment 5 and with the cavity 3, through the at least one outlet opening 11 of said cavity 3 for exhaustion of fumes, air and/or vapor and/or steam or a mixture thereof, out of the cavity 3 into said compartment 5.

(17) Additionally, the cavity 3 comprises an at least one inlet opening 12 for influx of steam or a mixture of steam and air. Said mixture may also be generated and/or ventilated by said fan element 7 and a steam generator 14, as a humidity generating means 14. Air may also be vented by the fan 7 from said compartment 5 also into the cavity 3, preferably mixed with steam from the steam generator 14. Said at least one duct 6 may be opened or closed by a here not shown at least one valve 13, which may be preferably a throttle valve and/or an electric valve.

(18) The at least one outlet opening 11 is arranged in an upper area 15 of the cavity 3, particularly in an upper wall 15 and the inlet opening 12 is arranged in a lower bottom area 16 of the cavity 3, particularly in a bottom wall 16 of the cavity 3.

(19) The main cooling fan 7 being the mixing element 7 is located in fluidic connection with said compartment 5. The main cooling fan 7 may be configured as a radial or a tangential fan, particularly a motor-driven fan, driven by a motor 25.

(20) As may be taken from FIG. 1 the inlet opening 12 is for input of steam or an air/steam mixture as a fluid into said cavity 3. Moreover, the outlet opening 11 is for output of fumes as fluid from said cavity 3.

(21) The at least one second sensor 9 is located in the cavity 3, here in or adjacent to the cavity rear wall 22.

(22) In FIG. 2, particularly a detailed top view of a heatable oven cavity 3 comprised in said steam-cooking oven 1 according to the first inventive embodiment is depicted. FIG. 3 shows a detailed sectional view of said cavity 3 and, particularly of said compartment 5 of said household appliance 1 showing the first inventive embodiment. Here the exhaust duct and its throttling valve 27 are evident, particularly comprising a throttling valve actuator 26 and an exhaust manifold from oven cavity 28.

(23) Said heatable cavity 3 is closed by a, here not shown, frontal access door 4. Foodstuff and/or a bakery ware 2 may be placed in a central region of the oven cavity 3. Usually oven cavities comprise means 21 for positioning foodstuff and/or a bakery ware, such as grids or trays, in different defined vertical positions, such as guiding rails or lateral embosses.

(24) The oven cavity 3 comprises several cavity walls (15, 16, and 17) such as a rear wall 22. Here in the detailed top view of FIG. 2, only the upper cavity wall 15 is visible. In the embodiment of the household appliance 1 according to the present invention a compartment 5 in form of a cooling chamber and/or cooling duct is located exterior of said cavity 3, particularly on top of said cavity 3. Said cooling chamber 5 is at least partially formed as a cochlea 20 and cooling fan exhaust duct, also comprising the main cooling fan 7 as a fan element 7, here a convection fan 7. The compartment 5 and the fan element 7 are configured and arranged such, that a flow of cooling air generated by the convection fan 7 is directed in defined directions, particularly into the oven cavity and to the outside, i.e. transporting fresh air to the cavity and transporting used air/steam to the outside.

(25) Particularly, the compartment 5 is arranged in fluid communication with said cavity 3 by, the here not shown at least one duct 6. The fan element 7 thus is capable for ventilating a fluid, e.g. fumes from the cavity 3.

(26) It can be immediately seen, that said cooling chamber and/or cooling channel 5, and thus the first sensor 8 is located at a position usually exposed to temperatures of 100 C. or less and to a relative humidity of usually 100% or less during operation of said household appliance 1, here within the cooling fan exhaust duct.

(27) Such household appliance 1 may comprise a steam generating means 14, as a humidity controlling means, particularly a humidity generating means 14, besides other humidity controlling means, particularly a humidity generating means 14 capable of generating steam and/or fresh air into the cavity, particularly capable of reducing or elevating humidity within said cavity. Such humidity controlling means 14, particularly a humidity generating means 14, may be selected from the group comprising steam generating means, e.g. steam generators, water bath, water ducts, or the like, valves for pressure and/or fluid outlets and/or inlets, particularly vapor and/or steam outlets and/or inlets, controls of water inlet means, e.g. shut-off valve means, or steam and vapor outlet adjustment means, valves and/or inlet and/or outlet ducts. Particularly, as a steam generating means 14, a liquid container of a steam generator may be formed to a bottom wall 16 of the oven cavity 3. Such liquid container of the steam generator 14 may be filled with a liquid, e.g. water, which can be evaporated by means of a heating element provided by the steam generator 14. An outlet duct 6 nay be formed by the liquid container, which allows the evaporated steam to reach a central region of the oven cavity 3.

(28) The convection fan element 7 can be controlled and operated such that a fan operation is ensured over the complete cooking cycle with a fan speed sufficient to for ventilating a fluid from and/or into said cavity 3. The fan rotation speed or the rotation direction can be varied to further improve ventilating, and particularly steam stirring and even distribution, if desired.

(29) According to the embodiment shown in FIGS. 1 and 2 a first sensor 8 being a humidity sensor for measuring relative humidity value as its input value, is arranged in the compartment 5 located exterior of said cavity 3, here in the cochlea area 20. Said first humidity sensor 8 is capable of measuring humidity, particularly relative humidity, within said compartment 5 at the sensor position, as an input value of said sensor 8. The household appliance 1 further comprises a temperature sensor 9 within the cavity 3. In connection with such temperature sensor 9, usually a recalibration algorithm is provided to convert the reading in whatever physical location of the sensor in the oven into the corresponding temperature in oven cavity center. Accordingly, a person skilled in the art will know how to select an appropriate position for such temperature sensor 9 in order to practice the present invention.

(30) In the household appliance 1 according to the present invention both the first humidity sensor 8, and the temperature sensor 9 are connected to a control unit 10. Said control unit 10 is capable of controlling the input and the output of steam into or out from the cavity 3, respectively, and additionally, optionally, the input and/or output of cooling air into the cavity 3. This control preferably is mediated by closing and/or opening of said at least one duct 6 and/or operating said fan element 7 and/or controlling a humidity controlling means, particularly a humidity generating means 14, preferably the steam generator 14.

(31) During the entire cooking process, but particularly starting at the end of a boost cycle operation of said household appliance 1 the first humidity sensor 8 may continuously measure in the cooling compartment 5 an input humidity value of the air contained in said compartment 5, which is correlated by the control unit 10 to a humidity index value.

(32) During a cooking cycle operation of said household appliance 1 and, optionally during a desteaming cycle operation of said household appliance 1, the first humidity sensor 8 continuously measures the relative humidity in the compartment 5, and the temperature sensor 9 continuously measures the temperature in the cavity 3, respectively. As both sensors 8 and 9 are connected to the control unit 10, said control unit correlates the respective continuously measured input values of the first humidity sensor 8 and the temperature sensor 9 to a humidity index value.

(33) This correlation is based on correlating said input values of said at least one first humidity sensor 8 and of said temperature sensor 9 to a matrix, which is deposited in said control unit 10. Such a matrix, in way of a non-limiting example, is shown in FIG. 3.

(34) Particularly, said correlation of the input value(s) with said index humidity value may be based on such matrix, particularly such simple lookup table as depicted in FIG. 3, which preferably is deposited in an appropriate electronic form in the control unit 10, i.e. capable to be processed. In the exemplary matrix shown in FIG. 4 columns represent ranges of temperature, here split in steps of 10 C., over the overall temperature working range of the household appliance 1.

(35) The rows in said matrix indicate the humidity index ranging from a relative humidity value of 0% to 100%, for example, in steps of 10%. The matrix itself has be then filled and populated with sensor values, serving as reference to the actually measured values. Said actually measured values serving as reference values where advantageously achieved experimentally by a set of tests using a reference humidity sensor placed in the cavity 3 of the household appliance 1.

(36) Said at least one first sensor 8 and said at least one second sensor 9 is connected to the control unit 10, and said control unit is capable of correlating said input value of said at least one first sensor 8 and of said at least one second sensor 9 to a humidity index value being selectable from such matrix comprising such humidity index value(s).

(37) Said at least one first sensor 8 and said at least one second sensor 9 is connected to a control unit 10, capable of correlating said input value of said at least one first sensor 8 and/or said at least one second sensor 9 to a humidity index value.

(38) For such correlation said input value of said at least one first sensor 8 and of said at least one second sensor 9 is compared to such matrix comprising such humidity index values, and said humidity index value is further compared to a set humidity value, and subsequently an output signal for controlling a humidity controlling means 14, e.g. the steam generator is determined and/or generated.

(39) A set humidity value is preferably set according to the desired conditions of the cooking process. It will be immediately understood that the user may set such set humidity value directly. For example, by selecting the desired humidity value. However, a household appliance 1 according to the present invention may also, particularly in its control unit 10, comprise default receipts, for example, for different kind of foodstuff and/or cooking processes. It will be also understood that desired humidity value during a boost cycle and desired humidity value during a cooking cycle may be independently set. However, also a combination of desired humidity value during a boost cycle and desired humidity value during a cooking cycle may be suggested to the user according to a desired cooking process, e.g. a receipt, preferably stored in the control unit.

(40) The set humidity value is preferably set by the user, like other cooking conditions, e.g. temperature and time, of a desired cooking process, depending on the specific cooking process to be performed. The boost cycle set value is preferably chosen such that the humidity value within the cavity at the end of the boost cycle is similar to the set humidity value of the cooking cycle.

(41) It will be immediately understood that the set humidity value is basically a value of humidity, and it may be set as the other parameters, e.g. time or temperature, by the user, according to cooking process. The estimated humidity index value is used as a control threshold, basically enabling/increasing steam generation if humidity is insufficient, i.e. below the set humidity value, and/or reducing/blocking it if humidity is ok or exceeding the set humidity value.

(42) The steps of a method according to the present invention are highlighted by the various arrows in FIG. 3. Accordingly, after adjustment of a set humidity value for a boost cycle and adjustment of a set humidity value for a cooking cycle and, optionally, for a de-steaming cycle of a cooking process, preferably by a user input, a step of humidity control, carried out during the cooking cycle and, optionally, the desteaming cycle. Particularly, said step of humidity control comprising at least the following steps: i) continuously measuring an input value by the at least one first sensor 8 and continuously measuring an input value by the at least one second sensor 9; ii) continuously correlating said input value of said at least one first sensor 8 and/or said at least one second sensor 9 to a humidity index value from the matrix, wherein said matrix comprises such humidity index value(s) deposited in the control unit 10 of the household appliance 1, said correlation comprising comparing said input value of said at least one first sensor 8 and said at least one second sensor 9 to the matrix; iii) comparing said humidity index value from step ii) to the set humidity value for a boost cycle and/or the cooking cycle and/or the de-steaming cycle of a cooking process from step a); and iv) determining and/or generating an output signal for controlling a humidity controlling means 14, particularly a humidity generating means 14, preferably a steam generating means 14; v) controlling said humidity controlling means 14 and generating a humidity value in the cavity 3 according to the output signal.

(43) The above described correlation and determination of the output value, in other words the deduction of the humidity index from said measured input value(s), may be preferably achieved by three consecutive or simultaneous steps highlighted by the various arrows in FIG. 3:

(44) At first, a temperature value is measured as an input value of the temperature sensor 9 in the cavity 3, for example, using a standard cavity temperature sensor. According to said measured input temperature value, the appropriate correlation matrix column is selected. For example, a temperature input value was measured which was in a certain temperature range. At second, the humidity sensor 8 measures its input value, i.e. an actual relative humidity value within the compartment 5, which is assigned to the appropriate value in the selected matrix column. In this particular example, the appropriate humidity index value according to the respective temperature column of the temperature range is selected. Said appropriate humidity index value is a value proportional to the input signal of relative humidity measured as an input signal by the first humidity sensor 8 in the compartment 5, particularly in the cooling air stream of the air-cooling channel and/or cooling chamber 5. It will be understood that the control unit 10 is configured such that a value in the selected temperature column may be identified being the most similar value in the selected correlation matrix column, particularly if such column represents a certain temperature range of about 10 C. or 5 C. steps. According to said selection of the appropriate humidity value in the selected matrix column, a respective humidity index value, here representing an estimated humidity index value, is assigned as an output signal. Said output signal may be than used to control various operations of the household appliance 1, particularly, for controlling the humidity controlling means 14, particularly a humidity generating means 14, particularly the operation of the steam generator 14. However, further other operations may be controlled based on said output signal, for regulating and/or controlling the humidity and/or temperature in the cavity. Particularly, controlling of a heating element, a steam generator means, valves for pressure and/or fluid outlets and/or inlets, particularly vapor and/or steam outlets and/or inlets, control of water inlet means, e.g. shut-off valve means or steam and vapor outlet adjustment means, valves and/or inlet and/or outlet ducts. It should be noted that according to the table provided in FIG. 4 as an example, the range of use of the control is indicated as a temperature range from 80 to 230 C. However, it is to be understood that the method and/or the household appliance according to the present invention is not bound thereto.

(45) Particularly, the household appliance 1 according to the embodiment depicted in FIGS. 1 and 2 comprises at least one duct 6, which is in fluid communication with the compartment 5 and the cavity 3, through at least one outlet opening 11 of said cavity 3 for exhaustion of air and/or vapor and/or steam or a mixture thereof, out of the cavity 3 and into said compartment 5. More particularly, the household appliance 1 according to the embodiment depicted in FIG. 2 may comprise at least one further duct 6, which is in fluid communication with the compartment 5 and the cavity 3, through at least one inlet opening 12 of said cavity 3 for influx of air and/or vapor and/or steam or a mixture thereof, for example, generated by said fan element 7 and/or a humidity controlling means, particularly a humidity generating means 14, into the cavity 3. Such duct 6, may be advantageously opened or closed by at least one valve 13, which may be configured as a throttle valve and/or an electric valve.

(46) The above-described correlation of said input value of said humidity sensor 8 and said temperature sensor 9 to the respective humidity index value occurs continuously during a cooking cycle operation of said household appliance 1, and advantageously allows estimating and thus controlling the actual relative humidity in the cavity 3. Particularly, the methods and/or household appliances according to the herein described embodiments of the invention advantageously allow the possibility to combine different conditions of humidity during different phases of a cooking operation, particularly during boost cycle and/or cooking cycle. Such operations are advantageously controlled and/or tunable by the steam generator duty cycle, particularly in the boost cycle, and the humidity value desired and/or achieved during a cooking cycle. Said humidity values within the cavity may be advantageously controlled and/or monitored by the method and/or household appliance according to the present invention. Said humidity values are particularly used to control the steam generator operation in closed loop.

(47) FIG. 5 shows such combination and/or examples of the various possible humidity index values depending on the accordingly chosen boost cycle steam generator performance are depicted. FIG. 6 depicts exemplarily the completely available matrix of combinations between boost cycle humidity values and humidity values during a cooking phase, particularly represented by the set humidity values. As may be taken from FIG. 5 for different desired cooking processes, and particularly for different categories of foodstuff, different combinations can be chosen to create the ideal cooking; examples are reported in FIG. 5.

(48) In this way, it is possible to deliver the desired right amount of humidity for each cooking phase and/or desired receipt. In connection therewith, it is to be understood that it is according to the receipt and cooking process to be performed often important and desired, particularly in an early phase of a cooking process, particularly in a boost cycle and/or in an early phase of the cooking cycle, to achieve special, specific or different conditions with respect to the rest of the cooking process itself.

(49) The graphs depicted in FIG. 4 represent a typical example for a cooking operation carried according to the method of the present invention. Particularly, in the present example, a boost cycle and cooking cycle set humidity value is chosen to keep a m relatively high humidity during the cooking cycle in the oven cavity 3 of about 80%, and thus set said value as the set humidity value for the cooking cycle. As may be taken from the depicted reference measurement using a reference sensor placed in the cavity, the actual relative humidity measured within the cavity is advantageously achieved by the present invention almost similar to said desired set humidity value during almost the entire cooking cycle. It will be immediately understood that the here indicated reference sensor measurement is not part of the invention; this is a direct measurement achieved with a laboratory system, meant to proof the accuracy of the invented method relying on a indirect measurement. Particularly, the desired set humidity value of about 80% relative humidity within the cavity 3 is depicted as a dashed line. As may be seen said FIG. 4 in a performed boost cycle of about 500 sec, which may be identified by an initial intensive operation of the steam generator from the lower part of the FIG. 4, the oven temperature raises to about 150 C., measured by the first temperature probe 9 within the cavity 3.

(50) An accordingly correlated humidity index value is depicted, which is correlated and deduced from the actual measurement of the input values of the temperature sensor 9 and the first humidity sensor 8 according to the method of the present invention. It can be immediately seen, that when the actual relative humidity value gets smaller than the desired set humidity value, the steam generator 14 again starts to operate and thus, the desired set humidity value is reached again in relative short time. This is possible as the control unit 10, which correlates the actually measured input values of the first sensor 8 in the compartment 5 and the temperature sensor 9 in the cavity 3 to an estimated humidity index value from the matrix, which serves as an output signal to control the steam generator 14.

(51) This is, as the first sensor 8 and the temperature sensor 9 are connected to the control unit 10, which is capable of correlating said input values of said first sensor 8 and said temperature sensor 9 to a humidity index value.

(52) The features of the present invention disclosed in the specification, the claims, and/or the figures may both separately and in any combination thereof be material for realizing the invention in various forms thereof.

LIST OF REFERENCE NUMERALS

(53) 1 Household appliance

(54) 2 foodstuff or bakery ware

(55) 3 cavity

(56) 4 access door

(57) 5 compartment

(58) 6 duct

(59) 7 fan element

(60) 8 first sensor

(61) 9, 9a, 9b second sensor

(62) 10 control unit

(63) 11 outlet opening

(64) 12 inlet opening

(65) 13 valve

(66) 14 humidity controlling means, particularly a humidity generating means

(67) 15 upper wall of the cavity

(68) 18 bottom wall of the cavity

(69) 17 side wall of the cavity

(70) 18 second humidity sensor

(71) 19 setting means

(72) 20 cochlea

(73) 21 grid

(74) 22 cavity rear wall

(75) 23 central fan

(76) 24 fan shield

(77) 25 motor

(78) 26 throttling valve actuator

(79) 27 throttling valve

(80) 28 Exhaust manifold from oven cavity