Induction Hob Control Unit Calibrates Cookware Temperature via Electrical Parameters

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Solution Overview

Problem

Existing induction hobs struggle to reliably determine the temperature of cooking utensils with unknown thermal properties without complex sensors, which can lead to inaccurate temperature control and potential overheating.

Innovation Solution

An induction hob with a control unit that runs a partially automated calibration program to determine thermal parameters by using electrical parameters, allowing for the identification and calibration of cooking utensils, even those with unknown thermal properties, using a function dependent on sensor temperature and specific thermal parameters, and storing these parameters for future use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a temperature sensor is used to determine cooking utensil temperature, then temperature control can be achieved, but the system cannot reliably determine temperature for utensils with unknown thermal properties

Engineering Contradiction:
Improvetemperature determination reliabilityVSAvoidcompatibility with unknown thermal properties
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The system changes from directly measuring temperature to measuring electrical parameters (impedance, inductance, resistance) that characterize the cooking utensil. By calibrating these electrical parameters against known thermal properties, the system can determine temperature for any utensil type without requiring direct temperature sensing of the utensil itself.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces an intermediary calibration process that links electrical parameters to thermal properties. Instead of directly measuring utensil temperature, the system uses the cooking vessel as an intermediary - measuring its electrical characteristics and using calibrated relationships to infer temperature, thereby solving the problem of unknown thermal properties.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If complex sensors are used to determine cooking utensil temperature, then accurate temperature control can be achieved, but the device complexity increases

Engineering Contradiction:
Improvetemperature measurement accuracyVSAvoidsensor complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical/thermal sensing systems with electrical measurement systems. Instead of using complex temperature sensors that directly contact the cooking utensil, the system uses electrical impedance, inductance, and resistance measurements through the induction heating element to infer temperature, thereby reducing device complexity while maintaining measurement precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system creates an electrical 'copy' or model of the cooking utensil's thermal behavior through calibration. By measuring electrical parameters and using pre-calibrated relationships, the system replicates temperature determination functionality without physically contacting or directly sensing the utensil, simplifying the overall system.

Inventive Principle:
Principle #26Copying

3Reliability

If calibration is performed for every cooking utensil, then accurate temperature control is achieved, but time is lost and user intervention is required

Engineering Contradiction:
Improvetemperature control accuracyVSAvoidcalibration time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs self-calibration automatically using the cooking utensil's own electrical characteristics. The control unit measures impedance, inductance, and resistance parameters and automatically determines thermal properties through pre-programmed calibration algorithms, eliminating the need for manual user intervention and reducing calibration time while maintaining accuracy.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent implements preliminary calibration data storage for multiple cooking utensil types. The system pre-stores calibration relationships between electrical and thermal parameters for various utensil types, allowing rapid automatic identification and calibration without requiring time-consuming manual procedures each time a utensil is used.

Inventive Principle:
Principle #10Preliminary action

4Productivity

If electrical parameters are used to identify cooking utensils, then quick identification is achieved, but reliable temperature determination requires additional thermal parameter calibration

Engineering Contradiction:
Improveidentification speedVSAvoidcalibration system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent merges the identification and calibration processes into a unified system. Electrical parameter measurements (impedance, inductance, resistance) serve dual purposes: both identifying the cooking utensil type and providing the basis for determining thermal properties through integrated calibration algorithms, thereby achieving both quick identification and reliable temperature determination without separate complex systems.

Inventive Principle:
Principle #5Merging (Combining)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables reliable and unambiguous identification of cooking utensils, preventing unnecessary recalibration and ensuring safe temperature control by using electrical parameters as a 'fingerprint' for quick identification and precise thermal modeling, thus avoiding complex sensors and user intervention uncertainties.

Implementation Method 1

Induction hob with at least one induction heating element

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

heating element (10) for heating a cooking utensil element (18)

Methodology Applied
Scientific EffectInduction heating: Induction Heating

Implementation Method 3

at least one temperature sensor (12) for determining a sensor temperature (14)

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2094059B1Induction cooking hob with at least one induction heating element and at least one temperature sensor
Publication Date: 2014.08.06 BOSCH SIEMENS HAUSGERATE GMBH
  • EP2094059B1 patent drawingFigure 1~2
  • EP2094059B1 patent drawingFigure 3~4
  • EP2094059B1 patent drawingFigure 5~6

AI summary

The invention relates to an induction hob with at least one induction heating element (10) and at least one temperature sensor (12) for determining a sensor temperature (14), as well as with a control unit (16) for identifying a cookware element (18) by means of at least one electrical characteristic parameter (R, L, RF) of the cookware element (18), wherein the control unit (16) for determining a cookware temperature (20) of the cookware element (18) uses a function (26) which depends at least on the sensor temperature (14) and on at least one thermal parameter (Tpot, TGlass) specific to the cookware element (18).In order to enable a reliable determination of the cookware temperature (20) even for cookware elements (18) with unknown thermal properties without complex sensors, it is proposed that the control unit (16) be designed to execute at least a semi-automated calibration program (22) to determine the thermal parameter (Tpot, TGlass) and to assign the thermal parameter (Tpot, TGlass) to the electrical characteristic (R, L, RF).