Method and control unit for operating an oven and oven

Abstract

The invention relates to a method for operating an oven (100) comprising a heating device (108) with a first heating element (110) and a second heating element (112) for heating a cooking chamber (102) of the oven (100), wherein the method comprises a step of reading a function signal representing a selected hot air frying function, a step of providing a heating signal to an interface to the heating device (108) using the function signal to activate the first heating element (110) and the second heating element (112) to heat the cooking chamber (102) to a temperature associated with the selected hot air frying function, and a step of outputting a fan signal to an interface to a hot air blower unit (119) of the oven (100) using the function signal.to set the hot air blower unit (119) to one of the minimum speeds assigned to the selected hot air frying function.

Description

The invention relates to a method and a control unit for operating an oven and an oven.Foods which are usually fried typically achieve poorer cooking results in the preparation in the oven, since the heat transfer of conventional operating modes is not sufficiently large and is significantly lower compared to frying in hot grease. Desired in fried, usually small-piece foods, such as French fries, is a well brown crisp crust and a juicey core. If the heat transfer is too low, too light a crisp crust is not sufficiently obtained for short cooking durations, the core being overgart or dried out for long cooking durations.The approach presented here is based on the object of creating an improved method and an improved control unit for operating an oven and an improved oven.According to the invention, this object is achieved by a method and a control unit for operating an oven and by an oven having the features of the main claims. Advantageous embodiments and further developments of the invention are evident from the following dependent claims.The approach presented advantageously makes it possible to create a possibility for being able to offer a user, without additional devices, a frying function for low-fat or fat-free frying. Advantageously, a user can save space in his premises or use it in some other way. Furthermore, the approach presented enables a large amount of food to be prepared in a time- and energy-efficient manner and hence costs incurred for a user to be reduced. Furthermore, further costs for obtaining the user can be dispensed with.A method for operating an oven is presented, which has a heating device with a first heating element and a second heating element for heating a cooking chamber of the oven. The method comprises a step of reading in a function signal representing a selected hot air frying function, a step of providing a heating signal to an interface to the heating device using the function signal in order to activate the first heating element and the second heating element in order to heat the cooking chamber to a temperature associated with the selected hot air frying function, and optionally a step of outputting a fan signal to an interface to a hot air blower unit of the oven using the function signal in order to set the hot air blower unit to a minimum rotational speed associated with the selected hot air frying function. It is also possible to use uncontrolled fans which are correctly set from the factory.The method can advantageously be used for ovens which can be used as household appliances or alternatively as industrial appliances. The oven can be formed, for example, as a stand device or as an built-in device. The oven is typically used to prepare a frying or cake. The heating device has the at least two heating elements, which can be used, for example, for different device functions, for example, hot air operation for top heat, bottom heat or a grilling function. By controlling both heating elements simultaneously, a greater heat transfer can advantageously take place. Advantageously, an electrical connection power of the oven, which can be, for example, 3.5 kW, can thereby be used as completely as possible. For this purpose, the hot air blower unit can be connected, the drive of which can be effected, for example, by a brushless direct current motor (BLDC). The hot air blower unit enables a circulating air operation, whereby the heat transfer and the baking time can be reduced compared to radiation modes. The cooking chamber can also be referred to as a receiving chamber, for example, into which food to be prepared can be introduced. By adjusting the temperature and minimum speed associated with the hot air frying function, a very good hot air frying result for an oven can advantageously be achieved. The hot air frying function of the oven preferably makes it possible to dispense with an external compact which is designed, for example, for carrying out such a hot air frying function, but which can often have a short service life. This makes it possible to save space in, for example, a kitchen.According to one embodiment, in the step of providing, the heating signal can be provided in order to be able to activate the first heating element in the form of an upper heat heating element or grille heating element and the second heating element in the form of an annular heating element. The two heating elements can be formed differently, for example, so that the temperature required for the hot air frying function can be achieved quickly and reliably with a cooking result that is satisfactory for a user, in which the food can be crispy on the outside and juiced on the inside.Furthermore, in the step of providing, the heating signal can be provided to the interface to the heating device in order to be able to heat the cooking chamber in a heating phase to a heating temperature which can be between 250° C. and 300° C., for example at above 260° C. or at above 270° C., in particular at 280° C. A heat transfer can advantageously be advantageously configured by the heating temperature, such that a result quality of the cooking result can be satisfactory for the user.According to one embodiment, in the step of providing, a further heating signal can be provided to the interface to the heating device in order to be able to set the heating device to a cooking temperature which can be lower than the heating temperature in a holding phase subsequent to the heating phase. Advantageously, the cooking temperature can be between 170° C. and 200° C., in particular 180° C. The selection of the temperature can advantageously ensure that a desired cooking result is achieved as energy-efficiently as possible. This means that an energy consumption for the hot air frying function can be advantageously adapted.Furthermore, in the step of providing, the further heating signal can be provided to the interface to the heating device when the heating temperature has been reached and additionally or alternatively when the heating temperature has been held for a predefined period of time. For example, a temperature profile can be set as a result, which is set automatically. This advantageously makes it possible to prevent, for example, a food to be prepared from burning.According to one specific embodiment, in the step of providing, the cooking temperature may be set in response to an input signal made by a user, which may represent a temperature change request of the user. Advantageously, the user can thereby determine the cooking temperature in the holding phase itself. This can be advantageous, for example, in connection with different meals and additionally or alternatively for achieving a cooking result desired by the user.Furthermore, in the step of outputting, the fan signal can be output using the function signal in order to be able to set the hot air blower unit to a minimum rotational speed which is associated with the selected hot air frying function and which can be between 1800 U / min and 2500 U / min, in particular at 2050 U / min. The minimum rotational speed can advantageously be selected such that a desired temperature can be reached as quickly as possible with a sufficiently high heat transfer in the cooking chamber. This on the one hand makes it possible to save energy costs and to reduce the cooking time.The preferred rotational speeds specified here provide an air speed in the cooking chamber of 0.8 m / s to 2 m / s. This allows a particularly effective hot air frying function to be achieved. The air velocity is particularly preferably above 1 m / s.In the output step, a further fan signal can be output to an interface to a cold air blower unit of the oven in order to be able to set the cold air blower unit to a setpoint rotational speed assigned to the hot air frying function in order to effect a setpoint air change rate. By setting the setpoint rotational speed, a desired cooking result can advantageously be achieved in a time-saving and efficient manner. This means that the food to be prepared can be crispy on the outside and juiced on the inside.According to one embodiment, the further fan signal can be output in the output step in order to be able to set the cold air blower unit to a setpoint rotational speed assigned to the hot air frying function in order to effect a setpoint air change rate between 5 and 15 I / min. Advantageously, the desired air exchange rate can be 13 to 14 l / min and thus 9 to 10 / h.The approach presented here furthermore provides a control unit which is designed to carry out, actuate or implement the steps of a variant of a method presented here in corresponding devices. This embodiment variant of the invention in the form of a device also enables the object on which the invention is based to be achieved quickly and efficiently.The control unit can be designed to read in input signals and to determine and provide output signals using the input signals. An input signal can represent, for example, a sensor signal that can be read in via an input interface of the control unit. An output signal may represent a control signal or a data signal that may be provided at an output interface of the control unit. The control unit can be designed to determine the output signals using a processing rule implemented in hardware or software. For example, for this purpose, the control unit can comprise a logic circuit, an integrated circuit or a software module and can be realized, for example, as a discrete component or be comprised by a discrete component.An oven is also provided which has a heating device with a first heating element and a second heating element, a hot air blower unit for generating an air flow, and a control unit in a variant mentioned above which is electrically coupled to the heating device.One aspect is that for the hot air frying function according to the invention, an air velocity of 0.8 to 2 m / s, preferably at least 1 m / s, is provided by the hot air blower in the cooking chamber.The oven can be formed as a household appliance, for example, but alternatively can also be used in the gastronomy, for example. Advantageously, the oven can execute a plurality of different appliance programs and thereby achieve different cooking results. Advantageously, the oven can comprise, in addition to conventional appliance programs, such as, for example, an upper heat function, lower heat function or a circulating air function, a hot air frying function, which can differ from the conventional appliance programs, inter alia, by, for example, a corresponding temperature, air circulation into and additionally or alternatively through the oven. The control unit can be arranged or integrated, for example, in or on an operating device of the oven.According to one embodiment, the first heating element and additionally or alternatively the second heating element can each be formed as an upper heat heating element, as a grill heating element or as an annular heating element. For example, the first heating element can be designed as an upper heat heater and the second heating element as a grill heater or vice versa. Alternatively, the first heating element can be designed as an upper heat heating element and the second heating element as an annular heating element or vice versa. Furthermore alternatively, for example, the first heating element can be designed as an annular heating element and the second heating element as a grille heating element, or vice versa. Advantageously, an electrical connection power of the oven, which can be, for example, 3.5 kW, can be used completely or at least approximately completely.The oven can also be formed as an built-in device. Advantageously, a standing surface otherwise required can be used by the user in another way, which can be advantageous in particular in the case of small kitchens.The oven can comprise an operating panel which enables a user to select the hot air frying function, a circulating air function, an upper and lower heating function and a grilling function. For example, the user may select the circulating air function or the top and bottom heating function for baking a cake, the grilling function for browning a frying, and the hot air frying function for preparing french fries.An exemplary embodiment of the invention is illustrated purely schematically in the drawings and is described in more detail below. It shows FIG. 1 shows a schematic illustration of an exemplary embodiment of an oven; FIG. 2 shows a flow diagram of an exemplary embodiment of a method for operating an oven; and FIG. 3 shows a block diagram of an exemplary embodiment of a control unit of an oven.FIG. 1 shows a schematic illustration of an exemplary embodiment of an oven 100. The oven 100 is only optionally formed as an built-in appliance and has an appliance body 102 which forms a cooking chamber 104 for receiving food to be prepared, and an appliance door 106 which closes the cooking chamber 104 and which is designed to be pivotable according to this exemplary embodiment. In order to be able to prepare food, the oven 100 has a heating device 108, which has a first heating element 110 and a second heating element 112. Merely optionally, the heating device 108 additionally has at least one further heating element. The first heating element 110 and / or the second heating element 112 can be shaped or are each shaped as an upper heat heating element 114, as a grill heating element 116 or as an annular heating element 118. According to this exemplary embodiment, the first heating element 110 is described as the top heat heating element 114 and the second heating element 112 as the grill element 116. The oven 100 further comprises a hot air blower unit 119 for generating an air flow. More specifically, the hot air blower unit 119 forces the air flow so that the heated air flows along the food to be cooked and gives heat to the food to be cooked. The hot air blower unit 119 is arranged here, for example, between the annular heating element 118 and the cooking chamber 102 behind a cooking chamber rear wall 120 and is designed, for example, as a brushless direct current blower (BLDC).For example, the cavity 104 has a cavity volume of at least 40I, 50I, 60I, or 70I.The oven 100 also has a control unit 121, which is electrically coupled to the heating device 108 and is designed to control and / or carry out a method for operating the oven 100, as is described, for example, in FIG. 2. The control unit 121 is arranged, for example, behind an operating panel 122 of the oven and / or is electrically coupled thereto. The control panel 122 is designed, for example, so that a user can select an appliance function of the oven 100, such as a hot air frying function, which is subsequently controlled and / or carried out by the control unit 121. For example, in addition to the selection of the hot air frying function, the control panel 122 enables the selection of a circulating air function, an upper and lower heating function and a grilling function. In addition, the control panel 122 enables the setting of a baking temperature.For cooking food in the oven 100, the customer can choose between different programs, also called modes of operation, which differ with regard to the connection of the heating elements and the output of the fans. An oven 100 is normally equipped with a plurality of heating elements which serve as energy source and emit heat into the cooking chamber 102 when the operation is switched on. The top heat heater 114 and grill heater 116 are located on the ceiling of the cooking chamber 102, and a bottom heat heater is located below the cooking chamber floor. The ring heater 118 is positioned behind the rear wall 120 of the cooking chamber 102. Depending on the device program to be carried out, one or more of these heating elements are activated, for example.The oven 100 is usually equipped with two blowers: the hot air blower unit 119 and a cold air blower unit 123, which is also described as a cooling fan, which is not shown in a visible manner due to the perspective of the representation. Both have different functions during the cooking process, which are explained below. According to this exemplary embodiment, the hot air blower unit 119 is located behind a suction opening 124 in the cooking chamber rear wall 120 of the cooking chamber 102. The rotation of the fan wheel forces convection. The air is sucked in through the round, perforated suction opening 124 in the middle of the cooking chamber rear wall 120. It then passes through the openings 126 to the left of the blower as viewed and through edges 128 of the rear wall 120. In this way, a flow is generated in the cooking chamber 102, so that the heated air can flow along the item to be cooked and can emit heat to the item to be cooked.The cooling fan 123 is placed over the cavity 102. Its primary task is to cool the oven 100 and the electronics located there, such as the control unit 121, during operation. Below the cooling fan 123, small openings are usually arranged, which allow the extraction of air and vapour from the cooking chamber 102. Above the openings, there is optionally a movable slide, which is also referred to as a flap. The amount of suction can be controlled on the one hand by the flap position, and on the other hand by the fan rotational speed of the cooling fan 123, which can vary between 1150 and 2400 U / min depending on the operating mode.In other words, the approach presented enables a so-called airfry method or hot air frying method for an oven 100. According to this exemplary embodiment, such a mode of operation for ovens 100 is carried out using intelligently available heating elements 114, 116, 118 and cooking parameters for a sufficiently high heat transfer to frying feeds. This achieves cooking results for conventional amounts of food, such as 1 kg of French fries, which are comparable to results of conventional hot air frits. In addition, the high heat transfer reduces a cooking duration and an energy consumption compared to conventional operating modes in the oven 100, such as hot air. In order to achieve this, the heating elements 110, 112 are preferably used as top heat heating elements 114 and grill heating elements 116 for the hot air frying function in order to significantly increase a heat transfer to the food compared to conventional ovens. Furthermore, a hot air blower speed of approximately 2050 U / min is provided for the hot air frying function, as well as a cooling fan speed of 1150 U / min, for example. According to this exemplary embodiment, an air exchange rate of 13-14 I / min; 9-10 / h is also provided for a cooking chamber flushing, in order to obtain a high cooking chamber humidity, as well as 280° C. for a heating phase and 180° C. for a holding phase as a preset. An adaptation of the latter temperature by the user is possible in this case. Preheating the oven 100 is also optional here.FIG. 2 shows a flow diagram of an exemplary embodiment of a method 200 for operating an oven, as was described, for example, in FIG. 1. The method 200 comprises a step 202 of reading in, a step 204 of providing and a step 206 of outputting. In step 202 of reading in, a function signal is read in, which represents a selected hot air frying function. In the providing step 204, a heating signal is provided to an interface to the heating device using the function signal to activate the first heating element and the second heating element in order to heat the cooking chamber to a temperature associated with the selected hot air frying function. For example, the first heating element is shaped in the form of an upper heat heating element and the second heating element is shaped in the form of a grill heating element or an annular heating element. In the output step 206, a fan signal is output to an interface to a hot air blower unit of the oven using the function signal in order to set the hot air blower unit to a minimum rotational speed associated with the selected hot air frying function.According to this exemplary embodiment, in step 204 of providing, the heating signal is provided to the interface to the heating device in order to heat the cooking chamber in a heating phase to a heating temperature which is between 250° C. and 300° C., in particular 280° C. A holding phase is furthermore optionally provided following the heating phase, for which a cooking temperature is set using a further heating signal provided to the interface to the heating device. This cooking temperature is, for example, 180° C. and is actuated, for example, as a preset. This takes place, for example, when the heating temperature has been reached and / or when the heating temperature has been held for a predefined period of time. Furthermore optionally, in step 204 of providing, the cooking temperature is set in response to an input signal made by a user, which represents a temperature change request of the user. For example, a preset cooking temperature is changed by the user.According to this exemplary embodiment, in the output step 206, the fan signal is output using the function signal in order to set the hot air blower unit to a minimum rotational speed, which is associated with the selected hot air frying function and lies between 1950 U / min and 2100 U / min, in particular at 2050 U / min. Additionally or alternatively, in the step 206 of outputting, a further fan signal is output to an interface to a cold air blower unit of the oven in order to set the cold air blower unit to a setpoint rotational speed assigned to the hot air frying function for effecting a setpoint air change rate. In this case, for example, the further fan signal is output in order to set the cold air blower unit to a setpoint rotational speed assigned to the hot air frying function in order to bring about a setpoint air change rate between 12 and 15 I / min.FIG. 3 shows a block diagram of an exemplary embodiment of a control unit 121 of an oven, as was described, for example, in FIG. 1. The control unit 121 is designed here to control and / or carry out a method for operating an oven which has a heating device with a first heating element and a second heating element for heating a cooking chamber of the oven. Such a method has already been mentioned and / or described in at least one of FIGS. 1 to 2.For this purpose, the control unit 121 has an read-in unit 300, a provisioning unit 302 and an output unit 304. The reading-in unit 300 is designed to read in a function signal 306 which represents a selected hot air frying function. The provision unit 302 is configured to provide a heating signal 308 to an interface to the heating device 108 using the function signal 306 in order to activate the first heating element and the second heating element and thereby heat the cooking chamber to a temperature associated with the selected hot air frying function. The output unit 304 is configured to output a fan signal 310 to an interface with a hot air blower unit 119 of the oven using the function signal 306 in order to set the hot air blower unit 119 to a minimum rotational speed associated with the selected hot air frying function.According to this exemplary embodiment, the provision unit 302 is furthermore designed to provide a further heating signal 312 to the interface to the heating device 108 in order to set the heating device 108 to a cooking temperature which is lower than the heating temperature in a holding phase subsequent to the heating phase. Furthermore optionally, the provision unit 302 is designed to provide the cooking temperature, for example using the further heating signal 213, in response to an input signal 314 made by a user, said input signal representing a temperature change request of the user. The input signal 314 is optionally read in by the read-in unit 300.The output unit 304 is designed to output a further fan signal 316 to an interface with a cold air blower unit 123 of the oven in order to set the cold air blower unit 123 to a setpoint rotational speed assigned to the hot air frying function in order to effect a setpoint air change rate.

Claims

Method (200) for operating an oven (100) having a heating device (108) with a first heating element (110) and a second heating element (112) for heating a cooking chamber (102) of the oven (100), wherein the method (200) comprises the following steps: reading in (202) a function signal (306) representing a selected hot air frying function; providing (204) a heating signal (308) to an interface with the heating device (108) using the function signal (306) in order to activate the first heating element (110) and the second heating element (112) in order to heat the cooking chamber (102) to a temperature associated with the selected hot air frying function, wherein in the step (204) of providing the heating signal (308) is provided to the interface with the heating device (108) in order to heat the cooking chamber (102) in a heating phase to a heating temperature which is between 250° C. and 300° C., in particular 280° C.Method (200) according to claim 1, wherein in the step (204) of providing, the heating signal (308) is provided to activate the first heating element (110) in the form of a top heat heater (114) and the second heating element (112) in the form of a grill heater (116) or an annular heater (118).Method (200) according to one of the preceding claims, wherein in a further step, a fan signal (310) is output (206) to an interface to a hot air blower unit (119) of the oven (100) using the function signal (306) in order to set the hot air blower unit (119) to a minimum rotational speed associated with the selected hot air frying function.Method (200) according to claim 3, wherein in the step (204) of providing, a further heating signal (312) is provided to the interface to the heating device (108) in order to set the heating device (108) to a cooking temperature which is lower than the heating temperature in a holding phase subsequent to the heating phase.Method (200) according to claim 4, wherein in the step (204) of providing, the further heating signal (312) is provided to the interface to the heating device (108) when the heating temperature has been reached and / or when the heating temperature has been maintained for a predetermined period of time.Method (200) according to claim 4, wherein in the step (204) of providing, the cooking temperature is set in response to an input signal (314) made by a user, which represents a temperature change request of the user.Method (200) according to one of the preceding claims, wherein in the step (206) of outputting, the fan signal (310) is output using the function signal (306) in order to set the hot air blower unit (119) to a minimum rotational speed associated with the selected hot air frying function, which is between 1800 U / min and 2500 U / min, in particular 2050 U / min.Method (200) according to one of the preceding claims, wherein in the step (206) of outputting a further fan signal (316) is output to an interface to a cold air blower unit (123) of the oven (100) in order to set the cold air blower unit (123) to a setpoint rotational speed associated with the hot air frying function for effecting a setpoint air change rate.Method (200) according to claim 8, wherein in the step (206) of outputting, the further fan signal (316) is output in order to set the cold air blower unit (123) to a setpoint rotational speed assigned to the hot air frying function for effecting a setpoint air change rate between 5 and 15 I / min, in particular 13 to 14 I / min or 9 to 10 / h.Control unit (121), which is designed to execute and / or control the steps (202, 204, 206) of the method (200) according to one of the preceding claims in corresponding units (300, 302, 304).An oven (100) comprising: a heater (108) comprising a first heater (110) and a second heater (112); a hot air blower unit (119) for generating an air flow; and a control unit (121) according to claim 10 electrically coupled to the heater (108) and the hot air blower unit (119).The oven according to claim 11, wherein the first heating element is formed as a top heat heater and the second heating element is formed as a grill heater or as an annular heater.The oven according to any one of claims 11 to 12, wherein the oven is formed as an built-in appliance.The oven according to any one of claims 11 to 13, comprising an operating panel (122) allowing a user to select the hot air frying function, a circulating air function, an upper and lower heating function and a grilling function.

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