Laundry dryer control system

Abstract

A laundry dryer control method including: setting the dryer to a default drying operation; performing the default drying operation when a user selects the default setting and does not select a dry boost setting; and performing a non-default drying operation when a user selects the default setting and does select a dry boost setting. In default operation, the dryer operates the drum and fan, and operates supplemental drying mechanism according to a predetermined schedule of “on” cycles and “off” cycles. If dry boost is selected, or if another non-default cycle is selected, the dryer operates the drum, fan and supplemental drying mechanism using a temperature feedback control loop, and operates until the laundry reaches a first dryness threshold.

1 . A laundry drying machine, comprising:
 a rotatable drum;   a fan configured to direct an air flow through the drum;   a supplemental drying mechanism configured to selectively heat the air flow;   a user interface having a first input and a second input; and   a control unit comprising a processor and a non-transitory memory storing instructions that, when executed by the processor, cause the control unit to:
 in response to selection of the first input, perform a default drying operation by activating and deactivating the supplemental drying mechanism according to a predetermined schedule of on cycles and off cycles at a first power output level; and 
 in response to selection of the second input, perform a non-default drying operation by measuring a temperature within the drum during operation of the drum and the fan and activating the supplemental drying mechanism when the temperature within the drum is less than a first temperature threshold at a second power output level, wherein the second power output level is greater than the first power output level. 
   
     
     
         2 . The laundry drying machine of  claim 1 , wherein the supplemental drying mechanism comprises at least one of an electric heating element, a gas heating element, or a heat pump. 
     
     
         3 . The laundry drying machine of  claim 1 , wherein the instructions, when executed by the processor, further cause the control unit to terminate the default drying operation after the predetermined schedule is complete. 
     
     
         4 . The laundry drying machine of  claim 1 , wherein the instructions, when executed by the processor, further cause the control unit to deactivate the supplemental drying mechanism when the temperature within the drum is greater than the first temperature threshold. 
     
     
         5 . The laundry drying machine of  claim 4 , wherein the instructions, when executed by the processor, further cause the control unit to measure a dryness level of contents of the drum and terminate the non-default drying operation when the dryness level reaches a first dryness threshold. 
     
     
         6 . The laundry drying machine of  claim 1 , wherein the instructions, when executed by the processor, further cause the control unit to:
 determine a first value of the first temperature threshold;   receive a temperature modification selection at the user interface; and   modify the first value of the first temperature threshold to a second value in response to receiving the temperature modification selection, wherein the second value is greater than the first value.   
     
     
         7 . The laundry drying machine of  claim 1 , wherein the instructions, when executed by the processor, further cause the control unit to perform a timed cooldown operation without temperature feedback. 
     
     
         8 . A laundry drying machine, comprising:
 a rotatable drum;   a fan configured to direct an air flow through the drum;   a supplemental drying mechanism configured to selectively heat the air flow;   a user interface having a first input and a second input; and   a control unit comprising a processor and a non-transitory memory storing instructions that, when executed by the processor, cause the control unit to:
 perform a default drying operation in response to the first input being in a positive state and the second input being in a negative state by activating and deactivating the supplemental drying mechanism according to a predetermined schedule of on cycles and off cycles at a first power output level; and 
 perform a non-default drying operation in response to the first input being in the positive state and the second input being in a positive state by measuring a temperature within the drum during operation of the drum and the fan and activating the supplemental drying mechanism when the temperature within the drum is less than a first temperature threshold at a second power output level, wherein the second power output level is greater than the first power output level. 
   
     
     
         9 . The laundry drying machine of  claim 8 , wherein the instructions, when executed by the processor, further cause the control unit to terminate the default drying operation after the predetermined schedule is complete. 
     
     
         10 . The laundry drying machine of  claim 9 , wherein the step of terminating the default drying operation further comprises:
 measuring a dryness level of contents of the drum;   initiating a supplemental drying process in response to determining that the dryness level of the contents of the drum is below a default dryness threshold; and   terminating the default drying operation after initiating the supplemental drying process.   
     
     
         11 . The laundry drying machine of  claim 10 , wherein the step of terminating the default drying operation after initiating the supplemental drying process further comprises:
 terminating the default drying operation upon completion of the supplemental drying process;   terminating the default drying operation upon determining that the dryness level of the contents of the drum reaches the default dryness threshold; or   terminating the default drying operation at a predetermined time after beginning the default drying operation.   
     
     
         12 . The laundry drying machine of  claim 8 , wherein the step of activating the supplemental drying mechanism according to a predetermined schedule comprises raising a process air temperature to a maximum value that is less than the first predetermined temperature threshold. 
     
     
         13 . The laundry drying machine of  claim 8 , wherein the instructions, when executed by the processor, further cause the control unit to perform a second non-default drying operation in response to the first input being in a negative state and the second input being in the negative state by:
 operating the drum and the fan;   measuring the temperature within the drum during operation of the drum and the fan;   activating the supplemental drying mechanism when the temperature within the drum is less than a second temperature threshold;   deactivating the supplemental drying mechanism when the temperature within the drum is greater than the second temperature threshold;   measuring a dryness level of contents of the drum; and   terminating the second non-default drying operation when the dryness level reaches the second predetermined dryness threshold.   
     
     
         14 . The laundry drying machine of  claim 8 , wherein the supplemental drying mechanism comprises at least one of an electric heating element, a gas heating element, or a heat pump. 
     
     
         15 . A laundry drying machine, comprising:
 a rotatable drum;   a fan configured to direct an air flow through the drum;   a supplemental drying mechanism configured to selectively heat the air flow; and   a control unit comprising a processor and a non-transitory memory storing instructions that, when executed by the processor, cause the control unit to:
 identify a plurality of activation parameters including a schedule of on cycles and off cycles and a drum temperature that is less than a drum temperature threshold, 
 identify a plurality of termination parameters including a time interval having passed and a dryness level measurement of drum contents reaching a dryness measurement threshold, 
 determine a state of an input, 
 modify a selected drying operation from a plurality of drying operations in response to the state of the input, and 
 perform the modified drying operation by:
 selecting one of the plurality of activation parameters and one of the plurality of termination parameters, and 
 activating the supplemental drying mechanism in accordance with the selected activation parameter and terminating the selected drying operation in accordance with the selected termination parameter. 
 
   
     
     
         16 . The laundry drying machine of  claim 15 , wherein the step of selecting one of the plurality of activation parameters further comprises selecting the drum temperature threshold from a plurality of drum temperature thresholds. 
     
     
         17 . The laundry drying machine of  claim 15 , wherein the step of selecting one of the plurality of termination parameters further comprises selecting the dryness measurement threshold from a plurality of dryness measurement thresholds. 
     
     
         18 . The laundry drying machine of  claim 15 , wherein the step of terminating the selected drying operation in accordance with the selected termination parameter further comprises:
 initiating a supplemental drying process; and   terminating the selected drying operation after initiating the supplemental drying process.   
     
     
         19 . The laundry drying machine of  claim 15 , wherein the supplemental drying mechanism comprises at least one of an electric heating element, a gas heating element, or a heat pump. 
     
     
         20 . The laundry drying machine of  claim 15 , wherein the instructions, when executed by the processor, further cause the control unit to perform a timed cooldown operation without temperature feedback.