Induction Cooktop Event Detection for Precise Temperature Control

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing cooking systems, particularly induction cooktops, face challenges in accurately monitoring food temperature and doneness due to sudden temperature changes caused by operations like food addition or flipping, which can be influenced by food type and sensor positioning.

Innovation Solution

A method using a closed-loop controller in an induction cooktop with embedded or external sensors to maintain constant cooking temperature by adjusting power based on the time derivative of temperature and power absorption, detecting food insertion and manipulation through abrupt variations exceeding predetermined thresholds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If temperature sensors are used to monitor food temperature in real-time, then cooking precision is improved, but the system becomes sensitive to abrupt temperature changes caused by food insertion or flipping operations

Engineering Contradiction:
Improvecooking precisionVSAvoidtemperature monitoring reliability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The system dynamically adjusts the interpretation of temperature changes based on the cooking phase. During heating phase, temperature drops are expected and acceptable. During maintenance phase, temperature drops below threshold trigger power adjustment. This dynamic adaptation resolves the contradiction by making the monitoring system intelligent rather than static.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the threshold parameter for temperature monitoring based on the current cooking phase. Two different thresholds are used: one for heating phase and another for maintenance phase. This parameter change allows the system to tolerate temperature variations during food manipulation while maintaining precision during stable cooking.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If the induction cooktop increases heating power to maintain constant temperature, then temperature stability is improved, but power consumption increases during food manipulation operations

Engineering Contradiction:
Improvetemperature stabilityVSAvoidpower consumption
Core Design Contradiction:
Stability of the object's compositionVSUse of energy by moving object

Solution Approach 1:

The system dynamically adjusts power consumption based on cooking phase and temperature deviation magnitude. During heating phase, high power is used to reach target temperature. During maintenance phase, power is adjusted only when temperature drops below threshold, rather than continuously. This dynamic approach maintains stability while reducing unnecessary energy consumption.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses feedback from temperature sensors to adjust power delivery. The controller continuously monitors temperature and compares it against phase-specific thresholds, adjusting power only when deviation exceeds acceptable limits. This feedback mechanism ensures temperature stability while avoiding excessive power consumption during normal operations.

Inventive Principle:
Principle #23Feedback

3Device complexity

If simple temperature threshold monitoring is used, then system complexity is reduced, but the ability to detect actual cooking events (food insertion, flipping) is worsened

Engineering Contradiction:
Improvesystem complexityVSAvoidcooking event detection
Core Design Contradiction:
Device complexityVSDifficulty of detecting and measuring

Solution Approach 1:

The system uses dynamic threshold adjustment based on cooking phase to detect events. During heating phase, larger temperature drops are expected and tolerated. During maintenance phase, even small drops indicate events like food insertion or flipping. This dynamic approach enables event detection without complex algorithms, maintaining low system complexity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The cooking process is segmented into distinct phases (heating and maintenance), each with its own temperature threshold criteria. This segmentation allows the simple threshold-based system to effectively detect different types of events by comparing temperature changes against phase-appropriate thresholds, avoiding the need for complex detection algorithms.

Inventive Principle:
Principle #1Segmentation

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 monitoring of cooking operations by generating event signals for food insertion and flipping, ensuring adherence to a chosen recipe by maintaining temperature within a narrow range, thus facilitating precise cooking control.

Implementation Method 1

an induction cooktop... operated so as to keep constant the cooking temperature

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

heating power provided by the induction cooktop

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 3

sensors coupled to the item of cookware

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP4240108A1Method of controlling a cooking system and related cooking system
Publication Date: 2023.09.06 WHIRLPOOL CORP
  • EP4240108A1 patent drawingFigure 1
  • EP4240108A1 patent drawingFigure 2
  • EP4240108A1 patent drawingFigure 3a~3d

AI summary

Operations such as adding food or flipping food in an item of cookware being heated may be detected by comparing with a threshold the time derivative of a sensed temperature and/or of heating power absorbed by an item of cookware, wherein the heating power is provided by an induction cooktop operated in order to keep constant the temperature value sensed by the sensors coupled to the item of cookware.