Patent ID: 8642928

Claim:
A cooking appliance for cooking food items using multiple cooking techniques comprising: a cabinet; an oven cavity including top, bottom, rear and opposing side walls that collectively define a cooking chamber; a user interface for establishing a desired cooking operation for a food item placed in the oven cavity, with the desired cooking operation having an associated set point temperature; an oven rack supported in the cooking chamber, said oven rack being spaced from the bottom wall of the oven cavity; a radiant heating element positioned below the oven rack and above the bottom wall in the oven cavity; a convection heating system including: an air plenum including a return plenum portion having an air intake defined by a plurality of openings located in the rear wall of the oven cavity, a blower plenum portion exposed to and downstream of the air plenum, and a discharge plenum portion downstream of the blower plenum, said discharge plenum including a plurality of nozzles opening to the oven cavity above the oven rack; a blower positioned in the blower plenum; a convection heating element positioned downstream of the blower; a first temperature sensor upstream of the blower; and a second temperature sensor downstream of the blower, wherein, during operation of the convection heating system, a convection air stream is drawn into the return plenum portion through the plurality of openings, directed across the convection heating element and introduced into the oven cavity through the plurality of nozzles, while being exposed to each of the first and second temperature sensors, through operation of the blower; a first control system receiving temperature signals from the first temperature sensor and regulating operation of the radiant heating element; and a second control system receiving temperature signals from the second temperature sensor and regulating operation of the convection heating element, wherein the first and second control systems constitute an overall temperature control system for regulating a cooking temperature in the oven cavity based on the temperature signals, said control system functioning to provide: a) a heater power reduction at a predetermined level below the set point temperature, regardless of whether the cooking temperature is increasing or decreasing; and b) another heater power reduction depending on a threshold rate at which the cooking temperature is increasing when a predetermined level below the set point temperature is reached, but does not reduce heater power when the cooking temperature is decreasing through the predetermined level.