Method for controlling the oven temperature, and temperature control unit

• US 7,554,061 B2
• Filed: 03/17/2006
• Issued: 06/30/2009
• Est. Priority Date: 04/15/2005
• Status: Active Grant

• Current Assignee: Electrolux Home Products Incorporated (AB Electrolux)
• Original Assignee: Electrolux Home Products Incorporated (AB Electrolux)
• Inventors: Ruther, Florian, Walther, Christoph, Andersson, Martin, Meider, Maike
• Primary Examiner(s): Paschall; Mark H
• Application Number:
  US11/378,736
• Publication Number:
  US 20060231551A1
• Time in Patent Office: 1,201 Days
• Field of Search: 219412-415, 219/494, 219/497, 219/499, 219/501, 219/505, 219/508, 219/506, 99325-333
• US Class Current: 219/492
• CPC Class Codes: F24C 7/08 Arrangement or mounting of control or safety devices
• CPC Class Codes: F24C 7/087 of electric circuits regulating heat

Abstract

Method for controlling the temperature of an oven, in particular a kitchen oven, so as to reach a preset temperature through a heating process during a predetermined heating period based on a control program, said control program consisting of a general basic control program predefined for a given type of oven and computationally adjusted by a static correction value that reflects the individual oven parameters, and/or a dynamic correction variable that takes into account variable operating parameters of the oven.

Claims

1. Method for controlling the temperature of an oven (10), in particular a kitchen oven, so as to reach a preset temperature (Tz) through a heating process during an appropriate heating period based on a control program,

said control program is composed of a general basic control program predefined for a given type of oven and computationally adjusted by a static correction value (Δ

t) that reflects the individual oven parameters, and/or a dynamic correction variable (Δ

t′

) that takes into account variable operating parameters of the oven,

a heating-time difference between the preset temperature (Tz) and an actual temperature value of a heating upslope factor reflecting a deviation of the rise of a heating curve from that of a reference curve as a multiplication factor is used as the static correction value (Δ

t) and/or the dynamic correction variable (Δ

t′

), and

a calibration process is based on a linear model of the heating phase.

2. Method as in claim 1, wherein the static correction value (Δ

t) is determined in a heating process of the empty oven by comparing a measured heating-time value with a heating-time reference value contained in the general basic control program.

3. Method as in claim 1, wherein the dynamic correction variable (Δ

t′

) is determined from the measured value of at least one operating parameter directly before or during the heating process.

4. Method as in claim 1, wherein the dynamic correction variable (Δ

t′

) is established by taking into account at least one of the operating parameters consisting of line voltage, starting temperature and energy consumption or power draw.

5. Method as in claim 4, wherein the dynamic correction variable (Δ

t′

) is calculated in a regression-analysis process on the basis of the heating-time difference, taking into account the operating parameters consisting of line voltage, staffing temperature and energy consumption or power draw, and utilizing a compensation formula of the polynomial type, said compensation formula generally being predefined for a particular type of oven.

6. Method as in claim 1, wherein a control variable, a variable derived from the control variable, or the heating time remaining until a preset temperature is reached, is continually displayed.

7. Method as in claim 4, wherein the line voltage, and measured oven current are used for determining the energy consumption or power draw.

8. Method as in claim 4, wherein the energy consumption or power draw is determined during a complete temperature control cycle, in particular during the complete heating process, and the value thus determined is fed to a display and/or stored in memory.

9. Method as in claim 8, wherein the energy consumption or power draw value is stored in accordance with one or several predefined storage protocols and the content of the memory is kept accessible in accordance with at least one retrieval protocol corresponding to the storage protocol.

10. Method as in claim 8, wherein an energy consumption or power draw reference value is stored in the memory and is subjected to a threshold discrimination process comparing the stored energy consumption or power draw reference value with the determined energy consumption or power draw, and that an error signal is emitted when a predefined differential threshold value is exceeded.

11. Method as in claim 8, wherein a total energy consumption value accumulated from consecutive temperature control programs and stored in accordance with a summation protocol is compared with a summary energy consumption reference value and that upon reaching said summary reference value a corresponding information signal appears on a user interface or a cleaning control signal is triggered.

12. Method as in claim 1, wherein for determining the static and/or dynamic correction values (Δ

t, Δ

t′

) an algorithm and/or input and/or output values can be modified via a user interface or an external interface.

13. Method as in claim 1, wherein the value of a parameter, especially the time of heating to a preset temperature or heating-time upslope, derived from the control program as adjusted based on the static and/or dynamic correction value (Δ

t, Δ

t′

), is stored and is subjected to a threshold-value discrimination process for a comparison with the corresponding value of earlier program sequences, and that an error signal is emitted when a predefined threshold-value difference is exceeded.

15. Method as in claim 1, wherein the heating upslope factor reflects the deviation of the rise of a corrected heating curve from that of the reference curve as the multiplication factor.

14. Temperature control unit (20) for implementing a method for controlling the temperature of an oven (10), in particular a kitchen oven, so as to reach a preset temperature (Tz) through a heating process during an appropriate heating period based on a control program, the control program being composed of a general basic control program predefined for a given type of oven and computationally adjusted by a static correction value (Δ

t) that reflects the individual oven parameters, and/or a dynamic correction variable (Δ

t′

) that takes into account variable operating parameters of the oven, a heating-time difference between the preset temperature (Tz) and an actual temperature value or a heating upslope factor reflecting a deviation of the rise the temperature control unit comprising;

a first program memory area (21) serving to store the general basic control program,

a correction stage (25) for computationally taking into account the static correction value and/or the dynamic correction variable in establishing the control program, and

a second program memory area (22) for storing the control program resulting from the correction value or values, or a corrected control variable for linking the control program to the general basic control program.

16. Temperature control unit as in claim 14, wherein the correction stage (25) is provided with a reference-value storage unit (23) for storing a control variable reference value, and a calculating unit for calculating the static correction value from the control variable reference value and a measured actual value, with the output of the calculating unit connecting to an input of the second program memory area.

17. Temperature control unit as in claim 16, wherein the calculating unit includes a subtraction stage for establishing as the static correction value a heating-time difference from a heating-time reference value and an actual heating-time value.

18. Temperature control unit as in claim 14, wherein the correction stage (25) includes a processing unit with at least one operating-parameter input for computing the dynamic correction variable from at least one of the operating parameters consisting of line voltage, starting temperature and energy consumption or power draw, by employing a polynomial compensation formula and a regression analysis procedure.

19. Temperature control unit as in claim 18, wherein the correction stage (25) includes a compensation-formula memory module (28) that connects to one input of the processing unit and serves to store a general compensation formula predefined for a given type of oven.

20. Temperature control unit as in claim 14, further comprising a user interface (12) or an external interface for modifying the general basic control program and/or an algorithm and/or input and/or output variables for the determination of the static and/or dynamic correction value.

21. Oven (10), in particular a kitchen oven, comprising:

a temperature control unit (20) for implementing a method for controlling the temperature of the oven (10) so as to reach a preset temperature (Tz) through a heating process during an appropriate heating period based on a control program, the control program being composed of a general basic control program predefined for a given type of oven and computationally adjusted by a static correction value (Δ

t) that reflects the individual oven parameters, and/or a dynamic correction variable (Δ

t′

) that takes into account variable operating parameters of the oven, a heating-time difference between the present temperature (Tz) and an actual temperature value or a heating upslope factor reflecting a deviation of the rise of a heating curve from that of a reference curve as a multiplication factor is used as the static correction value (Δ

t) and/or the dynamic correction variable (Δ

t′

) , a calibration process is based on a linear model of the heating phase, the temperature control unit comprising;

a first program memory area (21) serving to store the general basic control program,

a correction stage (25) for computationally taking into account the static correction value and/or the dynamic correction variable in establishing the control program, and

a second program memory area (22) for storing the control program resulting from the correction value or values, or a corrected control variable for linking the control program to the general basic control program,

the oven further comprising a control-variable measuring device (16), serving to quantify the actual value measured for determining the static correction value, specifically a heating-time measuring device, and/or an operating-parameter measuring device (15, 18, 19) for measuring the actual value of an operating parameter used in determining the dynamic correction variable, in particular a voltage measuring device and/or a temperature measuring device and/or an energy-consumption or power-draw measuring device,

which control-variable or operating-parameter measuring device is connected to an input of the correction stage (25) of the control unit (20).

22. Oven as in claim 21, wherein the energy-consumption or power-draw measuring device includes a line voltage measuring device (18) and an oven current measuring device (19) and a multiplier stage (31) connected to respective outputs of the line voltage measuring device and the oven current measuring device.

23. Oven as in claim 21, further comprising, connected in line with the energy consumption or power draw measuring device (18, 19, 31), an energy-data storage unit (32) specifically controllable via several storage protocols, and/or a display unit (11) for storing or, respectively, displaying a measured and stored actual energy-consumption or actual power-draw value.

24. Oven as in claim 21, further comprising an energy reference-value memory module (35) for storing an energy-consumption or power-draw reference value, and, connected to the energy reference-value memory and the energy-data storage unit (32), an energy discriminator stage (36) for executing a threshold-value discrimination process and for outputting an error signal in the event a predefined differential threshold value between the actual energy consumption and the energy reference value is exceeded.

25. Oven as in claim 21, further comprising a control-variable memory (33) with several memory areas for storing several values representing the actual values of the control variable as detected during temperature control operations, and, associated with the control-variable memory, a comparator unit (34) for comparing the actual values detected, which comparator is in the form of a discriminator stage that emits an error signal in the event a predefined threshold-value difference between stored actual values is exceeded.