Control method of washing machine

Patent metadata

Field	Value
Publication number	US-10494752-B2
Application number	US-201715608035-A
Country	US
Kind code	B2
Filing date	May 30, 2017
Priority date	May 30, 2016
Publication date	Dec 3, 2019
Grant date	Dec 3, 2019

Abstract

In a control method of a washing machine, a primary nephelometric turbidity unit (NTU) of washing water is sensed before a washing course is started in a washing cycle, a second NTU is sensed based on the primary NTU, and a washing time, an amount of washing agent, and/or a number of times of rinsing are varied based on a difference value between the primary NTU and the secondary NTU, thereby improving washing performance and washing efficiency.

First claim

What is claimed is:

1. A control method of a washing machine, comprising:
sensing an amount of laundry;
determining a first washing condition including a washing time, an input amount of washing agent, and a number of times of rinsing, corresponding to the sensed amount of laundry;
automatically putting a washing agent corresponding to the input amount determined based on the first washing condition, and performing water supply;
after the water supply is completed, performing a first laundry wetting process during a first set time (T1) by a driving motor rotating a drum of the washing machine;
after the first laundry wetting process is performed, stopping the driving motor and sensing a first nephelometric turbidity unit (NTU) while the driving motor is stopped; and
after the first NTU is sensed, performing a second laundry wetting process by the driving motor rotating the drum, subsequently stopping the driving motor, and sensing a second NTU while the driving motor is stopped,
wherein the first washing condition is adjusted, based on a difference value (Ns) between the second NTU and the first NTU, and a washing operation is performed based on the adjusted washing condition in which the input amount of the washing agent is changed based on a first pollution level of the laundry.

2. The control method of claim 1 , wherein, in the performing of the first laundry wetting process, the drum is rotated at a first rotation speed during the first set time (T1),
when the first set time T1 elapses, the rotation of the drum is stopped during a second set time (T2), and
the sensing of the first NTU is performed within the second set time (T2).

3. The control method of claim 2 , wherein each of the first set time (T1) and the second set time (T2) is 60 seconds,
the sensing of the first NTU is performed 30 times in 3 seconds within the second set time (T2), and
an average value of six values obtained by abandoning 12 upper values and 12 lower values among calculated 30 NTUs is determined as the first NTU.

4. The control method of claim 2 , wherein, when it is determined that the first NTU is less than a set value (A1), the sensed amount of laundry is compared with a set value (B1),
when it is determined that the sensed amount of laundry is equal to or smaller than the set value (B1), the second laundry wetting process and the second NTU sensing are performed n number of times, wherein n is greater than 0, and
when it is determined that the sensed amount of laundry exceeds the set value (B1), the second laundry wetting process and the second NTU sensing are performed 2 times n number of times.

5. The control method of claim 4 , wherein each of the plurality of second laundry wetting processes includes:
a first process of rotating the drum at a rotation speed greater than the first rotation speed during a third set time; and
a second process of stopping the rotation of the drum during the second set time after the first process is ended,
wherein a second NTU sensing is performed in the second process,
wherein a third set time is longer than the first set time,
wherein the second NTU sensing is identical to the first NTU sensing.

6. The control method of claim 5 , wherein a maximum value among NTUs calculated by performing an NTU sensing the n or 2 times n number of times is finally selected as the second NTU,
wherein the difference value (Ns) is a difference value between the second NTU and the first NTU.

7. The control method of claim 1 , wherein, when the difference value (Ns) is smaller than a first set value (a), the washing operation is to be performed based on a first washing course,
wherein, when the difference value (Ns) is equal to or greater than the first set value (a) and smaller than a second set value (b), the washing operation is to be performed based on a second washing course, and
wherein, when the difference value (Ns) is equal to or greater than the second set value (b), the washing operation is to be performed based on a third washing course.

8. The control method of claim 7 , wherein, when it is determined that the first NTU is equal to or greater than the set value (A1), the washing operation is performed under the adjusted washing condition without the second laundry wetting process and the second NTU sensing.

9. The control method of claim 7 , wherein, in the first washing course, no washing agent is additionally put.

10. The control method of claim 9 , wherein, in the first washing course, a washing time and a number of times of rinsing are decreased as compared with those in the determining of the first washing condition.

11. The control method of claim 7 , wherein, in the second washing course, a washing agent is additionally put.

12. The control method of claim 11 , wherein, in the second washing course, a washing time and a number of times of rinsing are maintained as those in the determining of the first washing condition.

13. The control method of claim 7 , wherein, in the third washing course, a washing agent is additionally put,
wherein an amount of the additionally put washing agent is greater than that of the washing agent additionally put in the second step second washing course.

14. The control method of claim 13 , wherein, in the third washing course, a washing time and a number of times of rinsing are increased as compared with those in the second washing course.

15. The control method of claim 7 , wherein, when the performance of any one of the first to third washing courses is completed, a rinsing cycle including a drainage operation is started.

16. The control method of claim 8 , wherein the pollution level of the laundry is divided into light soil, normal soil having a pollution level higher than that of the light soil, and heavy soil having a pollution level higher than that of the normal soil,
wherein the first pollution level is a pollution level corresponding to that of the light soil.

17. The control method of claim 16 , wherein the washing time and the number of times of rinsing, which are determined in the determining of the first washing condition, are a washing time and a number of times of rinsing, which correspond to the normal soil.

18. The control method of claim 16 , wherein, in the first washing course, no washing agent is additionally put, the washing time is decreased by 10 minutes as compared with the first washing condition, and the number of times of rinsing is decreased by once,
wherein, in the second washing course, a washing agent is additionally put such that an amount of washing agent, corresponding to the normal soil, is supplied, and the washing time and the number of times of rinsing are maintained under the first washing condition, and
wherein, in the third washing course, a washing agent is additionally put such that an amount of washing agent, corresponding to the heavy soil, is supplied, the washing time is increased by 20 minutes as compared with that in the second washing course, and the number of times of rinsing is increased by once or twice as compared with that in the second washing course.

19. The control method of claim 6 , wherein the n is 2.

20. The control method of claim 5 , wherein the third set time is 5 minutes.

Assignees

• Lg Electronics Inc

Inventors

• Kim Kyounglan

Classifications

• D06F34/22

  Condition of the washing liquid, e.g. turbidity · CPC title

• F23N3/082

  using electronic means · CPC title

• H02P6/16

  Circuit arrangements for detecting position · CPC title

• H02K29/06

  with position sensing devices (H02K29/03 takes precedence) · CPC title

• G01M3/3245

  using a level monitoring device (G01M3/3272 takes precedence) · CPC title