Cooking appliance

Abstract

A cooking appliance device, in particular induction cooking appliance device, includes a muffle which has a muffle wall and is configured to define at least partially a cooking chamber. A heating element is provided to heat the muffle wall, with a first sensor unit detecting a temperature of the muffle wall.

Claims

1. An induction cooking appliance device, comprising: a muffle having a muffle wall and configured to define at least partially a cooking chamber; a heating element configured to heat the muffle wall; a first sensor unit configured to detect a temperature of the muffle wall, wherein the first sensor unit is configured to detect the temperature of the muffle wall automatically at a hottest point of the muffle wall; a second sensor unit configured to detect a temperature of air in the cooking chamber; a control unit configured to compare the temperature detected by the first sensor unit with a stored reference value indicating a maximum permissible temperature within the cooking chamber, and, in response to the temperature detected by the first sensor unit reaching the reference value, to reduce a power level of the heating element; and wherein the control unit is further configured to determine a power output directed to an item to be cooked in a first operating mode based on the temperature detected by the first sensor unit, and to determine the power output directed to the item to be cooked in a second operating mode based on the temperature detected by the second sensor unit.

2. The cooking appliance device of claim 1, wherein the heating element is embodied as an induction heating element.

3. The cooking appliance device of claim 1, further comprising a further heating element embodied as a resistance heating element.

4. The cooking appliance device of claim 1, further comprising a third sensor unit configured to detect a temperature of the item to be cooked located within the cooking chamber.

5. The cooking appliance device of claim 1, wherein the control unit is configured to consider an emissivity of the muffle wall when determining the power output directed onto the item to be cooked located within the cooking chamber.

6. The cooking appliance device of claim 1, further comprising: a third sensor unit configured to detect a temperature of the item to be cooked located within the cooking chamber; wherein the control unit is configured to determine, in dependence on the temperature detected by the third sensor unit, the power output that is directed onto the item to be cooked located within the cooking chamber in the first and second operating modes.

7. The cooking appliance device of claim 6, wherein the control unit is configured to consider an emissivity of the muffle wall when determining the power output directed onto the item to be cooked located within the cooking chamber.

8. An induction cooking appliance, comprising: a cooking appliance device, said cooking appliance device comprising a muffle having a muffle wall and configured to define at least partially a cooking chamber; an induction heating element configured to heat the muffle wall; a resistance heating element; a first sensor unit configured to detect a temperature of the muffle wall, wherein the first sensor unit is configured to detect the temperature of the muffle wall automatically at a hottest point of the muffle wall; a second sensor unit configured to detect a temperature of air within the cooking chamber; a control unit configured to compare the temperature detected by the first sensor unit with a stored reference value indicating a maximum permissible temperature within the cooking chamber, and to reduce a power level of the induction heating element in response to the temperature detected by the first sensor unit reaching the reference value; and wherein the control unit is configured to determine a power output directed to an item to be cooked in two different operating modes: (a) a convection operating mode, wherein the resistance heating element and a fan of the induction cooking appliance are activated and wherein the induction heating element is deactivated, and wherein the control unit determines the power output based on the temperature determined by the second sensor unit; and (b) a thermal radiation operating mode, wherein the induction heating element is activated, and wherein the resistance heating element and the fan are deactivated, and wherein the control unit determines the power output based on the temperature determined by the first sensor unit.

9. The cooking appliance device of claim 8, wherein the cooking appliance device includes a third sensor unit configured to detect a temperature of the item to be cooked located within the cooking chamber.

10. The cooking appliance device of claim 8, wherein the control unit is configured to consider an emissivity of the muffle wall when determining the power output directed onto the item to be cooked located within the cooking chamber.

11. The cooking appliance device of claim 8, wherein the cooking appliance device includes a third sensor unit configured to detect a temperature of the item to be cooked located within the cooking chamber, and a control unit configured to determine, in dependence on the temperature detected by the third sensor unit, the power output that is directed onto an item to be cooked located within the cooking chamber in the convection operating mode and in the thermal radiation operating mode.

12. The cooking appliance device of claim 11, wherein the control unit is configured to consider an emissivity of the muffle wall when determining the power output directed onto the item to be cooked located within the cooking chamber.

13. A method for operating an induction cooking appliance device having a muffle, a heating element, and a control unit, said method comprising: measuring in at least one operating status a temperature of a muffle wall of the muffle as the muffle wall is heated by the heating element, wherein the temperature is automatically measured at the hottest point of the muffle wall; comparing the measured temperature of the muffle wall with a stored reference value indicating a maximum permissible temperature of the muffle wall; determining, by the control unit, a power output directed to an item to be cooked in a first operating mode based on the measured temperature of the muffle wall; determining, by the control unit, the power output directed to the item to be cooked in a second operating mode based on a measured temperature of air within a cooking chamber defined by the muffle; and reducing, by the control unit, a power level of the heating element in response to the measured temperature of the muffle wall reaching the reference value.

14. The cooking appliance of claim 8, further comprising a third sensor unit configured to detect a temperature of the item to be cooked located within the cooking chamber.

15. The cooking appliance of claim 14, wherein the control unit is configured to determine the power output based on the temperature detected by the third sensor unit in both the convection operating mode and the thermal radiation operating mode.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Wherein:

(2) FIG. 1 shows a cooking appliance with a cooking appliance device in a schematic representation,

(3) FIG. 2 shows a muffle delimiting a cooking chamber, a resistance heating element, a fan unit and two induction heating elements of the cooking appliance device in a schematic representation and

(4) FIG. 3 shows a schematic diagram in which a temperature and a power output are plotted against a time.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE PRESENT INVENTION

(5) FIG. 1 shows a cooking appliance 32 which is embodied as an induction cooking appliance, with a cooking appliance device 10 which is embodied as an induction cooking appliance device. The cooking appliance 32 could for example be embodied as a grill appliance and/or as a steam cooking appliance and/or as a microwave appliance. In the present exemplary embodiment the cooking appliance 32 is embodied as an induction oven. The cooking appliance device 10 is embodied as an induction oven device.

(6) The cooking appliance device 10 has a muffle 12. The muffle 12 partially defines a cooking chamber 16. In an operating status, the muffle 12, together with a cooking appliance door 34, essentially defines the cooking chamber 16. The cooking appliance device 10 has the cooking appliance door 34.

(7) The muffle 12 has five muffle walls 14. In the figures, objects present on a multiple basis are provided with a single reference character only. In the operating status, the muffle walls 14, together with the cooking appliance door 34, essentially define the cooking chamber 16.

(8) One of the muffle walls 14 is embodied as a muffle bottom wall 36. One of the muffle walls 14 is embodied as a muffle top wall 38. One of the muffle walls 14 is embodied as a muffle rear wall 40. Two of the muffle walls 14 are embodied as a muffle side wall 42, 44. Only one of the muffle walls 14 is described below.

(9) The cooking appliance device 10 has an operator interface 46 for entering and/or selecting operating parameters (cf. FIG. 1), for example a heating capacity and/or a heating power output density and/or a heating zone. The operator interface 46 is provided to output the value of an operating parameter to an operator.

(10) The cooking appliance device 10 has a control unit 30. The control unit 30 is provided to perform actions and/or change settings, depending upon operating parameters entered by means of the operator interface 46. In an operating status, the control unit 30 regulates the feeding of energy to at least one heating element 18 (cf. FIG. 2).

(11) In the present exemplary embodiment the cooking appliance device 10 has two heating elements 18. Alternatively, the cooking appliance device 10 could in particular have a different number of heating elements 18. For example the cooking appliance device 10 could have precisely one single heating element 18. Alternatively, the cooking appliance device 10 could for example have at least three, in particular at least four, advantageously at least five and preferably multiple heating elements 18.

(12) In an operating status the heating elements 18 are arranged outside the cooking chamber 16. A lower heating element 18 of the heating elements 18 is arranged in an installation location underneath the muffle wall 14 embodied as the muffle bottom wall 36. The lower heating element 18 is arranged on the muffle wall 14 embodied as the muffle bottom wall 36.

(13) An upper heating element 18 of the heating elements 18 is arranged in an installation location above the muffle wall 14 embodied as a muffle top wall 38. The upper heating element 18 is arranged on the muffle wall 14 embodied as the muffle top wall 38.

(14) Alternatively, at least one heating element 18 could be arranged on a muffle wall 14 embodied as a muffle side wall 42, 44 and/or on a muffle wall 14 embodied as a muffle rear wall 40. Only one of the heating elements 18 is described below.

(15) The heating element 18 is provided for heating the muffle wall 14, on which the heating element 18 is arranged. In the present exemplary embodiment the heating element 18 heats the muffle wall 14 inductively. The heating element 18 is embodied as an induction heating element.

(16) The cooking appliance device 10 has a fan unit 48 (cf. FIGS. 1 and 2). The fan unit 48 has a fan rotatable about an axis of rotation. In the operating status the fan unit 48 generates a fluid flow by means of the fan. In the operating status the fan unit 48 circulates fluids located within the cooking chamber 16.

(17) Viewed from the front, the fan unit 48 is arranged in a rear area of the cooking chamber 16. The fan unit 48 is arranged in the vicinity of the muffle rear wall 40.

(18) The cooking appliance device 10 has a cooking appliance rear wall 50. The cooking appliance rear wall 50 is arranged within the cooking chamber 16. Viewed from the front, the cooking appliance rear wall 50 is arranged in front of the fan unit 48. The cooking appliance rear wall 50 is arranged in the vicinity of the muffle rear wall 40.

(19) The cooking appliance device 10 has a further heating element 24 (cf. FIGS. 1 and 2). The further heating element 24 is embodied as a resistance heating element. Viewed from the front the heating element 24 is arranged behind the cooking appliance rear wall 50. The heating element 24 is arranged in the vicinity of the muffle rear wall 40. The heating element 24 is arranged in the vicinity of the fan unit 48.

(20) The cooking appliance device 10 has a sensor unit 20 (cf. FIGS. 1 and 2). The sensor unit 20 is arranged on the muffle wall 14. In the present exemplary embodiment the sensor unit 20 is arranged within the cooking chamber 16. The sensor unit 20 is provided for detection of a temperature of the muffle wall 14.

(21) In the operating status the sensor unit 20 detects a temperature of the muffle wall 14 at a hottest point 22 of the muffle wall 14. The sensor unit 20 is arranged at the hottest point 22 of the muffle wall 14. In the present exemplary embodiment the sensor unit 20 has a detector embodied as a resistance sensor.

(22) The cooking appliance device 10 has a second sensor unit 26 (cf. FIGS. 1 and 2). The second sensor unit 26 is arranged within the cooking chamber 16. Viewed from the front, the second sensor unit 26 is arranged behind the cooking appliance rear wall 50. The second sensor unit 26 is arranged in the vicinity of the muffle rear wall 40. In the operating status the second sensor unit 26 detects a temperature within the cooking chamber 16. In the operating status the second sensor unit 26 detects a temperature of a fluid located within the cooking chamber 16.

(23) The cooking appliance device 10 has a third sensor unit 28 (cf. FIGS. 1 and 2). The third sensor unit 28 is arranged within the cooking chamber 16. In the operating status the third sensor unit 28 detects a temperature of an item to be cooked 52 located within the cooking chamber 16. The third sensor unit 28 has a detector embodied as a probe. In the operating status the sensor unit 28 is arranged partially within the item to be cooked 52. Alternatively, an embodiment which avoids the third sensor unit 28 is conceivable. In particular the control unit 30 could estimate a temperature of an item to be cooked 52 located within the cooking chamber 16, for example on the basis of the temperature detected by the sensor unit 20 and/or the temperature detected by the second sensor unit 26.

(24) In the operating status the third sensor unit 28 wirelessly transmits a value for the temperature of the item to be cooked 52 located within the cooking chamber 16 to the control unit 30. Alternatively or additionally the sensor unit 28 could in particular be connected to the control unit 30, in particular via an electrical cable, and in particular transmit a value for the temperature of the item to be cooked 52 located within the cooking chamber 16 via the connection to the control unit 30.

(25) In the operating status the control unit 30 determines the power output directed onto the item to be cooked 52 located within the cooking chamber 16. In the operating status the control unit 30 determines the power output directed onto the item to be cooked 52 located within the cooking chamber 16, depending upon the temperature detected by the sensor unit 20.

(26) In the operating status the control unit 30 takes account of the temperature detected by the second sensor unit 26 when determining the power output directed onto the item to be cooked 52 located within the cooking chamber 16. In the operating status the control unit 30 takes account of the temperature detected by the third sensor unit 28 when determining the power output directed onto the item to be cooked 52 located within the cooking chamber 16.

(27) In the operating status the control unit 30 determines power output directed the item to be cooked 52 located within the cooking chamber 16 in different operating modes, depending upon temperatures detected by different sensor units 20. 26, 28. In the present exemplary embodiment the control unit 30 differentiates between three operating modes. Alternatively, the control unit 30 could distinguish a greater number of operating modes.

(28) In a convection operating mode, the control unit 30 takes account of the power output based upon convection when determining the power output directed onto the item to be cooked 52 located within the cooking chamber 16. In the convection operating mode the control unit 30 broadly proceeds on the assumption that the power output directed onto the item to be cooked 52 located within the cooking chamber 16 is essentially based on convection. In the convection operating mode the further heating element 24 and the fan unit 48 are activated and in particular the heating element 18 deactivated.

(29) In the convection operating mode the control unit 30 uses the following formula as an initial basis for determining the power output directed onto the item to be cooked 52 located within the cooking chamber 16:
{dot over (Q)}.sub.conv=h.Math.A.sub.conv.Math.(T.sub.air−T.sub.food),

(30) Herein h is a coefficient of convection, which in particular is dependent upon a flow rate of a fluid located in the cooking chamber 16 and on a temperature of a fluid located in the cooking chamber 16. A.sub.conv is a surface of the item to be cooked 52 located within the cooking chamber 16. T.sub.air is the temperature detected by the second sensor unit 26. T.sub.food is the temperature detected by the third sensor unit 28.

(31) The control unit 30 in the convection operating mode uses the following formula for determining the power output directed onto the item to be cooked 52 located within the cooking chamber 16:
{dot over (Q)}.sub.conv=k.sub.conv.Math.(T.sub.air−T.sub.food),

(32) Herein k.sub.conv is a known coefficient, which in particular is stored in a memory unit of the control unit 30 and which in particular can be determined by means of experimental trials and/or by means of theoretical calculations.

(33) In a thermal radiation operating mode the control unit 30 takes account of the power output based upon thermal radiation when determining the power output directed onto the item to be cooked 52 located within the cooking chamber 16. In the thermal radiation operating mode, the control unit 30 broadly proceeds from the assumption that the power output directed onto the item to be cooked 52 located within the cooking chamber 16 is based essentially on thermal radiation. In the thermal radiation operating mode the heating element 18 is activated and in particular the further heating element 24 and the fan unit 48 deactivated.

(34) It is assumed in the following, with no loss of generality, that the heating element 18 heats the muffle wall 14 embodied as the muffle top wall 38. Alternatively, the heating element 18 could heat at least one other muffle wall 14, such as for example the muffle wall 14 embodied as the muffle bottom wall 36, wherein in particular the following examination may be used analogously.

(35) In the thermal radiation operating mode the control unit 30 uses the following formula as an initial basis for determining the power output directed onto the item to be cooked 52 located within the cooking chamber 16:
{dot over (Q)}.sub.rad=σ.Math.ε.Math.A.sub.top.Math.F.Math.(T.sub.top.sup.4<T.sub.food.sup.4)

(36) Herein σ is a Stefan-Boltzmann constant. ε is the emissivity of the muffle wall 14. A.sub.top is a surface of the muffle wall 14 in particular embodied as a muffle top wall 38. F is a factor, which is dependent on the geometry of the muffle 12. T.sub.top is the temperature detected by the sensor unit 20. T.sub.food is the temperature detected by the third sensor unit 28.

(37) In the thermal radiation operating mode the control unit 30 uses the following formula for determining the power output directed onto the item to be cooked 52 located within the cooking chamber 16, which in particular represents an in particular satisfactory approximation of the formula used as the initial basis:
{dot over (Q)}.sub.rad≈k.sub.rad.Math.(T.sub.top−T.sub.food)

(38) Herein k.sub.rad is a known coefficient, which in particular is stored in a memory unit of the control unit 30 and which in particular can be determined by means of experimental trials and/or by means of theoretical calculations.

(39) The emissivity of the muffle wall 14 is considered in the known coefficients. In the operating status the control unit 30 takes account of an emissivity of the muffle wall 14 when determining the power output directed onto the item to be cooked 52 located within the cooking chamber 16.

(40) In a mixed operating mode the control unit 30 takes account of a power output based upon thermal radiation and a power output based upon convection when determining the power output directed onto the item to be cooked 52 located within the cooking chamber 16. In the mixed operating mode the heating element 18, the further heating element 24 and the fan unit 48 are activated.

(41) The control unit 30 could for example take account of the power output based upon thermal conduction in at least one operating mode, in particular in the convection operating mode and/or in the thermal radiation operating mode and/or in the mixed operating mode, when determining the power output directed onto the item to be cooked 52 located within the cooking chamber 16. In the present exemplary embodiment the control unit 30 ignores the power output based upon thermal conduction when determining the power output directed onto the item to be cooked 52 located within the cooking chamber 16.

(42) For example in the thermal radiation operating mode the control unit 30 could in addition take account of a convection, in particular a natural convection, when determining the power output directed onto the item to be cooked 52 located within the cooking chamber 16. The thermal radiation operating mode could for example be a grill operating mode.

(43) In one method for operating the cooking appliance device 10 in the operating status a temperature of the muffle wall 14 is measured. Depending upon the temperature of the muffle wall 14, the power output directed onto the item to be cooked 52 located within the cooking chamber 16 is determined.

(44) In the operating status the control unit 30 uses the temperature within the cooking chamber 16 detected by the second sensor unit 26 and/or the temperature detected by the sensor unit 20 for safety purposes. A reference value for the temperature detected by the second sensor unit 26 and/or by the sensor unit 20 is stored in a memory unit of the control unit 30. The reference value for the temperature detected by the second sensor unit 26 and/or by the sensor unit 20 indicates a maximum permissible temperature within the cooking chamber 16. In the operating status the control unit 30 reduces the power output directed onto the heating element 18 and/or the further heating element 24 as soon as the temperature detected by the second sensor unit 26 and/or by the sensor unit 20 reaches the reference value (cf. FIG. 3). In this case the control unit 30 controls and/or regulates the temperature within the cooking chamber 16 and/or the temperature of the muffle wall 14 to correspond to the reference value.

(45) For example at least one further operating mode, in particular in addition to the operating modes described, could be stored in a memory unit of the control unit 30, in which the control unit 30 could in particular operate the heating element 18 and/or the further heating element 24 depending upon a temperature within the cooking chamber 16.

REFERENCE CHARACTERS

(46) 10 Cooking appliance device 12 Muffle 14 Muffle wall 16 Cooking chamber 18 Heating element 20 Sensor unit 22 Hottest point 24 Further heating element 26 Second sensor unit 28 Third sensor unit 30 Control unit 32 Cooking appliance 34 Cooking appliance door 36 Muffle bottom wall 38 Muffle top wall 40 Muffle rear wall 42 Muffle side wall 44 Muffle side wall 46 Operator interface 48 Fan unit 50 Cooking appliance rear wall 52 Item to be cooked