System for gaseous fuel ignition for a cooking appliance

Abstract

An improved ignition system is provided for use with a gaseous fuel burner on a cooktop of an appliance. A flame sensor is used to detect the presence of a flame at the gaseous fuel burner. When the flame is detected as absent for at least a certain predetermined period of time, the ignition system attempts to reignite the flame. During the predetermined time period, the ignition system does not attempt to reignite the flame even though the flame is not detected. As such, the flame has an opportunity to restore itself fully around the burner during the predetermined time period before the ignition system is activated.

What is claimed is: 
     
         1 . A method for igniting a gas burner, the steps comprising:
 providing a gaseous fuel to the burner;   operating an ignition system to ignite the gaseous fuel to the burner;   detecting whether a flame is present at the burner over at least a first time period Δt 1  and, if so, then
 determining, after a flame has been detected at the burner for a first time period Δt 1 , whether a flame is absent from at least a portion of the burner over at least a second time period Δt 2 , and, if so, then
 repeating the steps of operating and detecting. 
 
   
     
     
         2 . A method for igniting a gas burner as in  claim 1 , further comprising the step of detecting whether a valve controlling gas flow to the burner has been activated so as to provide a gaseous fuel to the burner. 
     
     
         3 . A method for igniting a gas burner as in  claim 1 , further comprising the step of detecting whether the ignition system has been activated. 
     
     
         4 . A method for igniting a gas burner as in  claim 1 , wherein the first time period Δt 1  is about one second. 
     
     
         5 . A method for igniting a gas burner as in  claim 1 , wherein the first time period Δt 1  is in the range of about 0.5 second to about 1.5 seconds. 
     
     
         6 . A method for igniting a gas burner as in  claim 1 , wherein the second time period Δt 2  is about 3 seconds. 
     
     
         7 . A method for igniting a gas burner as in  claim 1 , wherein the second time period Δt 2  is about 2.5 seconds to about 3.5 seconds. 
     
     
         8 . A method for igniting a gas burner as in  claim 1 , further comprising the steps of:
 stopping the flow of gaseous fuel to the burner; and   ceasing the step of determining whether a flame is present at the burner.   
     
     
         9 . A method for igniting a gas burner as in  claim 1 , wherein the step of detecting whether a flame is present comprises monitoring a signal from a flame sensor positioned at the burner. 
     
     
         10 . A method for igniting a gas burner as in  claim 1 , wherein the step of determining whether a flame is absent from at least a portion of the burner comprises monitoring a signal from a flame sensor positioned at the burner. 
     
     
         11 . A method for igniting a gas burner as in  claim 1 , further comprising the steps of:
 determining whether gaseous fuel is provided to the burner and whether the ignition system is operating and, if so, then executing said step of detecting whether a flame is present at the burner over at least a first time period Δt 1 .   
     
     
         12 . A method for igniting a gas burner as in  claim 1 , further comprising the step of deactivating the ignition system if a flame is present at the burner. 
     
     
         13 . A method for igniting a gas burner as in  claim 1 , further comprising the step of continuing to operate the ignition system during the first time period Δt 1 . 
     
     
         14 . An ignition system for a cooking appliance using a gaseous fuel, comprising:
 a gas burner configured for the receipt of gaseous fuel;   a valve connected to a gas supply and configured for controlling the flow of gaseous fuel to the gas burner;   an ignition system configured for igniting the gaseous fuel supplied to the gas burner;   a flame sensor configured for detecting the presence of a flame at the gas burner;   at least one controller configured for
 activating the ignition system to light the gaseous fuel at the burner; 
 detecting whether a flame is present at the burner over at least a first time period Δt 1  and, if so detected, then
 determining, after a flame has been detected at the burner for a first time period Δt 1 , whether a flame is absent from at least a portion of the burner over at least a second time period Δt 2 , and, if so, then 
 repeating the steps of activating, detecting, and determining. 
 
   
     
     
         15 . An ignition system for a cooking appliance using a gaseous fuel as in  claim 14 , wherein the at least one controller is further configured for
 continuing operation of the ignition system during the step of detecting whether a flame is present at the burner over at least the first time period Δt 1 .   
     
     
         16 . An ignition system for a cooking appliance using a gaseous fuel as in  claim 14 , wherein the first time period Δt 1  is about one second. 
     
     
         17 . An ignition system for a cooking appliance using a gaseous fuel as in  claim 14 , wherein the first time period Δt 1  is about 0.5 second to about 1.5 seconds. 
     
     
         18 . An ignition system for a cooking appliance using a gaseous fuel as in  claim 14 , wherein the second time period Δt 2  is about 3 seconds. 
     
     
         19 . An ignition system for a cooking appliance using a gaseous fuel as in  claim 14 , wherein the second time period Δt 2  is about 2.5 seconds to about 3.5 seconds. 
     
     
         20 . An ignition system for a cooking appliance using a gaseous fuel as in  claim 14 , wherein the second time period Δt 2  is about 5 seconds.