Drum type washing machine and dryer and method for automatic drying by using the same

An automatic drying method for a drum type washing machine and dryer having an upper temperature sensor A1 and a lower temperature sensor A2 mounted at upper and lower portions of the inside of the duct respectively, for performing a drying cycle by using a difference of temperatures sensed at the upper temperature sensor A1 and the lower temperature sensor A2 respectively, comprising the steps of:

• upon starting the drying cycle, determining a temperature at an inside of a tub of being higher than a first reference set temperature T1;
• if the temperature at the inside of the tub is higher than the first reference set temperature T1, comparing the difference A1-A2 of temperatures sensed at the upper temperature sensor A1 and the lower temperature sensor A2 respectively to a second reference set temperature T2;
• and
• if the difference A1-A2 of temperatures is higher than the second reference set temperature T2, assuming a laundry amount by calculating a time period starting from beginning of drying to the present time.

A drum type washing machine and dryer comprising:

• a tub having a tub rotatably mounted therein;
• a duct of an air circulating passage for drying laundry in the tub;
• a duct temperature sensor at a lower portion of an inside of the duct, for sensing a temperature,
• wherein a difference between a maximum temperature sensed at the duct temperature sensor and a temperature sensed at the present time is used, for determination of a laundry amount and dryness of the laundry.

An automatic drying method for a drum type washing machine and dryer for performing a drying cycle by using a temperature difference of a duct temperature sensor A2 at a lower portion of an inside of a duct, comprising the steps of:

• upon starting the drying cycle, determining a temperature at the inside of the tub of being higher than a first reference set temperature T1;
• if the temperature at the inside of the tub is higher than the first reference set temperature T1, obtaining a maximum temperature Tmax of the duct temperature sensor A2;
• comparing a difference Tmax−A2 of the maximum temperature Tmax and a temperature sensed at the duct temperature sensor A2 to a second reference set temperature T2;
• and
• if the difference Tmax−A2 is higher than the second reference set temperature T2, calculating a time period from starting of drying to the present time, for assuming the laundry amount.

An automatic drying method for a drum type washing machine and dryer for performing a drying cycle by using temperatures sensed at a plurality of temperature sensors, comprising the steps of:

• calculating a temperature difference C between first, and second temperature sensors at a beginning stage of the drying cycle;
• determining a sign ± of the difference, for calculating a corrected temperature of the second temperature sensor;
• if the temperature of the second temperature sensor becomes higher than a first reference set temperature T1, calculating a difference between the temperature of the first temperature sensor and the corrected temperature of the second temperature sensor, to obtain a dryness determining value Δ;
• and
• comparing the dryness determining value Δ and a second reference set temperature T2, and terminating the drying cycle according to a result of the comparison.