Induction Cooker Vibration Sensing for Accurate Boiling Detection
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Solution Overview
Problem
Conventional induction heating cookers face challenges in accurately detecting the state of an object being heated, particularly in fluorine-coated vessels and when dealing with non-water contents, leading to delayed boiling detection and increased risk of overflow, and struggle to detect resonant sounds that can cause cooking failures.
Innovation Solution
An induction heating system that includes a vibration detecting section, a vibration waveform extracting section to identify frequencies twice that of the induction heating frequency, and a determining section to assess the object's state based on extracted waveforms, along with a resonant sound detection mechanism to identify and mitigate resonant sounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional vibration detection methods are used, then the device complexity is low, but the measurement precision of boiling state is insufficient leading to delayed detection
Solution Approach 1:
The vibration signal is segmented into multiple frequency components through Fourier transform. The system separately analyzes different frequency bands (first frequency component around 2x induction frequency, second frequency component at lower frequency) to detect different stages of boiling, enabling precise measurement without requiring a completely complex detection system
Solution Approach 2:
A vibration detecting section acts as an intermediary to convert the physical vibration of the cooking vessel into an electrical signal. This intermediary component enables precise measurement of boiling state by capturing vibration characteristics that are otherwise difficult to measure directly
2Productivity
If heating output is increased to speed up cooking, then the productivity improves, but the risk of overflow increases due to delayed boiling detection
Solution Approach 1:
The system continuously monitors vibration signals and provides real-time feedback about the boiling state. When the vibration characteristics indicate boiling has occurred, the control section adjusts the heating output accordingly, enabling the system to maintain high productivity while preventing overflow through timely feedback-based control adjustments
3Temperature
If the cooking vessel has a thick aluminum alloy layer to improve thermal efficiency, then the heat conduction improves, but the vibration transmission for detection deteriorates
Solution Approach 1:
The system segments the vibration signal into multiple frequency components through Fourier transform. By analyzing different frequency components separately, the system can identify boiling characteristics even when the thick aluminum alloy layer attenuates certain vibration frequencies, maintaining detection accuracy while allowing improved thermal efficiency
Solution Approach 2:
The system utilizes mechanical vibration characteristics of the cooking vessel as a detection mechanism. By detecting the vibration patterns caused by boiling and comparing them against reference patterns, the system can accurately determine boiling state despite the thick aluminum alloy layer, as the vibration signature remains distinctive
4Ease of manufacture
If fluorine coating is applied to the cooking vessel to prevent sticking, then the non-stick performance improves, but the vibration characteristics change making boiling detection difficult
Solution Approach 1:
The vibration signal is segmented into multiple frequency components, allowing the system to identify boiling characteristics that persist despite the fluorine coating. The first frequency component (around 2x induction frequency) and second frequency component (lower frequency) provide complementary information that helps maintain detection accuracy on fluorine-coated surfaces
Solution Approach 2:
The system dynamically adjusts its detection strategy based on the cooking conditions. By continuously monitoring vibration characteristics and comparing them against reference patterns, the system can adapt to the modified vibration transmission properties introduced by the fluorine coating, maintaining accurate boiling detection
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
This solution enables precise detection of the object's state, preventing cooking failures like overflow and effectively suppressing resonant sounds, thereby ensuring accurate and efficient cooking.
Implementation Method 1
an induction heating section 13 for inductively heating a cooking vessel 11
Implementation Method 2
induction heating cooker recited in e.g. patent document 1
Implementation Method 3
a vibration detecting section 114 provided at a position underneath a top plate 112 to detect a vibration resulting from generation, detachment, disappearance and the like of air bubbles
Implementation Method 4
a heating controlling section 117 to reduce an output of the induction heating coil 113
Data Source
AI summary
An object of the invention is to accurately detect a state of an object to be heated in a cooking vessel and effectively avoid cooking failure. An induction heating section (13) inductively heats a cooking vessel (11). A vibration detecting section (14) detects a vibration of the cooking vessel (11) via a top plate (12). A vibration waveform extracting section (15) extracts a vibration waveform of a frequency component having a frequency equal to a predetermined multiplication product of an induction heating frequency, from a waveform of the vibration detected by the vibration detecting section (14). A determining section (16) determines a state of an object to be heated, based on the vibration waveform extracted by the vibration waveform extracting section (15).