Methods and systems for ignition of a smoke unit fuel source
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Solution Overview
Problem
Existing grill systems face challenges in achieving optimal smoke flavor production due to difficulties in reliably monitoring and controlling the ignition of smoke unit fuel sources, and in accurately modulating the operating speeds of inductive loads like shaded-pole motors, which are affected by supply voltage variations and low power factors.
Innovation Solution
A cooking device with a smoke unit and electronic controller that adjusts the igniter's energy supply and fan power based on measured energy rates and temperatures, and a transfer function-based algorithm to control inductive loads, ensuring optimal smoke production and motor speed modulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the igniter provides excessive energy to the fuel source, then ignition occurs, but there is too much combustion for the airflow and oxygen supply, resulting in inefficient burn
Solution Approach 1:
The system uses a temperature sensor to continuously monitor the temperature of the fuel source and provides feedback to the controller. The controller adjusts the igniter activation time based on this feedback to achieve optimal ignition without excessive combustion, resolving the contradiction between ignition reliability and combustion efficiency.
Solution Approach 2:
The system dynamically adjusts the igniter activation time based on real-time temperature measurements and environmental conditions. This dynamic control allows the system to provide just the right amount of energy for reliable ignition while preventing excessive combustion that would waste energy and reduce efficiency.
2Loss of energy
If the igniter provides too little energy to the fuel source, then combustion efficiency is maintained, but there is not enough heat to generate a self-sustained combustion reaction
Solution Approach 1:
The temperature sensor continuously monitors the fuel source temperature and provides feedback to the controller. When the temperature indicates insufficient heat for self-sustained combustion, the controller extends the igniter activation time to provide additional energy, ensuring reliable ignition while maintaining combustion efficiency.
Solution Approach 2:
The system dynamically adjusts the igniter activation duration based on real-time temperature measurements. This allows the system to provide sufficient energy for self-sustained combustion when needed while avoiding excessive energy input that would reduce combustion efficiency.
3Measurement precision
If a sensor is implemented to detect combustion products for closed loop control, then combustion monitoring capability is improved, but the system becomes impractical due to cost and reliability requirements
Solution Approach 1:
The system uses temperature as an intermediary parameter to indirectly monitor combustion status. Instead of implementing complex and expensive combustion product sensors, the temperature sensor serves as a mediator that provides sufficient information for control decisions, achieving practical combustion monitoring without excessive system complexity.
Solution Approach 2:
The system replaces the need for complex combustion product detection mechanisms with a simpler temperature-based control system. This substitution achieves the essential monitoring function with greater practicality, lower cost, and improved reliability.
4Ease of operation
If TRIACs are used to modulate motor speed, then ease of operation is improved, but performance is adversely affected by low power factor and supply voltage variations
Solution Approach 1:
The system uses feedback from current and voltage measurements to continuously monitor motor operating conditions. Based on this feedback, the controller dynamically adjusts the TRIAC firing angle to compensate for supply voltage variations and maintain optimal motor performance, resolving the contradiction between ease of operation and performance reliability.
Solution Approach 2:
The system dynamically changes the TRIAC firing angle parameter based on real-time measurements of supply voltage and motor current. This parameter adjustment compensates for low power factor and voltage variations, maintaining reliable motor performance while preserving the ease of operation provided by TRIAC-based control.
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
The solution enables consistent and efficient smoke flavor production while improving the accuracy and efficiency of motor speed control, addressing the limitations of existing technologies in grill systems.
Implementation Method 1
determine an average rate of energy supplied to the igniter during a predetermined period of time of activation of the igniter
Implementation Method 2
ignite fuel contained in the fuel box
Data Source
AI summary
In an aspect, data characterizing a plurality of measurements of a rate of energy supplied to an igniter of a smoke unit and of a temperature of a region proximate the igniter, acquired during a predetermined period of time of igniter activation, can be received. A maximum time of igniter activation can be determined based on an average rate of energy supplied to the igniter and an average temperature of the region proximate the igniter. Whether a total length of time, during which the igniter is activated and during a subsequent period of time, exceeds the maximum time of activation can be determined, and the igniter can be deactivated in response to determining that the total length of the time exceeds the determined maximum time of activation.