Sequential Heating Element Control for Rotisserie-Style Oven Cooking
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Solution Overview
Problem
Implementing a rotisserie cooking system within a domestic cooking appliance is challenging due to the need for a motor outside the oven compartment to avoid heat exposure, making it difficult and expensive to integrate a rotatable skewer system.
Innovation Solution
A method utilizing multiple heating elements within the oven cavity, controlled by a programmable logic controller, to sequentially energize and de-energize elements in a duty cycle that simulates rotisserie cooking by periodically exposing a stationary food item to heat from different directions, mimicking the rotation without the need for a motorized skewer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a motor is installed outside the oven compartment to avoid heat exposure, then the motor can operate reliably, but the device complexity and cost increase due to the need for a rotatable skewer system with a shaft penetrating the compartment body
Solution Approach 1:
The patent extracts the motor from the oven compartment entirely, placing it in an external location such as the back wall or side of the appliance housing. This eliminates the need for heat-resistant motor housings and complex sealing arrangements, while the motor's output is transmitted to the food item through a simple belt-driven system that rotates the food item directly without requiring a penetrating shaft
Solution Approach 2:
The patent replaces the traditional mechanical skewer-and-shaft system with a belt-driven rotation system. Instead of using a rigid shaft that penetrates the compartment body, a flexible belt connects the externally mounted motor to the food item, allowing for simpler installation and maintenance while achieving the same rotational function
2Adaptability or versatility
If a motor and skewer system are integrated within the oven compartment, then the rotisserie function is achieved, but the manufacturing cost and installation difficulty increase significantly
Solution Approach 1:
The patent segments the rotisserie system into two independent parts: an externally mounted motor unit and an internally mounted food rotation mechanism. This segmentation allows each component to be manufactured, tested, and installed separately, reducing overall system complexity and making the appliance more manufacturable and easier to service
Solution Approach 2:
The patent introduces a belt as an intermediary element that connects the externally mounted motor to the food item inside the oven compartment. This intermediary allows power transmission without requiring direct mechanical coupling through the compartment wall, simplifying both manufacturing and installation processes
3Productivity
If heating elements are operated simultaneously, then heating efficiency is high, but temperature control precision decreases due to inability to regulate individual element operation
Solution Approach 1:
The patent implements periodic action by sequentially energizing different heating elements in a predetermined sequence rather than operating them simultaneously. The controller activates each heating element for a specific duration, creating a cycling pattern that provides both direct radiant heat and indirect convective heat, achieving efficient heating while maintaining precise temperature control through regulated on/off timing
Solution Approach 2:
The patent changes the operational parameters of the heating elements by controlling the duration and sequence of energization for each element. The controller adjusts the on/off timing and sequence of heating elements based on temperature feedback, dynamically changing operational parameters to maintain precise temperature control while achieving high heating efficiency through optimized heat delivery patterns
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
Effectively simulates rotisserie cooking by maintaining consistent temperature fluctuations around the food item, ensuring even cooking without the complexity and cost of a traditional rotisserie system, while maintaining temperature control and browning effects.
Implementation Method 1
periodically and evenly exposed to direct radiation from the heat source
Implementation Method 2
the first heating element and the second heating element are sequentially energized
Implementation Method 3
a convection fan operatively coupled to the controller and configured to circulate air within the oven cavity
Data Source
AI summary
A method is provided for cooking a food item in an oven cavity of a cooking appliance, the cooking appliance including a first heating element and a second heating element spaced about the oven cavity. The method includes a first stage wherein the first heating element and the second heating element are sequentially energized according to a first duty cycle in which the first heating element is energized at a first time for a first duration and the second heating element is energized at a second time for a second duration. The first duration and the second duration are regulated based on a measured temperature and a first predetermined target temperature.