Household washing machines have entered a replacement period. In economically developed areas, double drum washing machines tend to be gradually replaced by automatic washing machines. In the introduction of the types, functions and characteristics of automatic washing machines, the media publicity seems to be led by the advertisements of various brands of washing machines. In fact, any product, as long as it can exist, always has its reasonable existence factors. It is neither objective, scientific nor fair to exaggerate the advantages of one kind compared with the disadvantages of another. This paper attempts to objectively introduce the advantages and disadvantages of various automatic washing machines for buyers' reference.

1? What is the significance of fuzzy control?

Since 1990s, countries all over the world have attached great importance to the research and application of fuzzy theory, and pursued more scientific washing methods in the application of washing machines. It can adopt different washing procedures for different fabrics, different washing amounts and different conditions (such as water temperature and detergent). At present, the fuzzy control washing machines in the domestic market are mostly imported from abroad. Because the formulation of the national standard of fuzzy control washing machine in China is too backward, there is no exact normative definition to restrict it, and there are different opinions, including fuzzy technology theory, logical control theory and artificial intelligence theory. However, with the passage of time, people have some understanding of it, that is, the fuzzy control washing machine should be able to automatically judge the weight of clothes, the hardness of materials, and automatically detect the dirty water in the washing bucket. Fuzzy control washing machine should be able to automatically preselect water level, water flow intensity and washing time, and automatically correct clothes deviation. It should also be able to monitor and adjust these operating parameters in time during the whole washing process to achieve the best washing effect.

According to the above requirements, the fuzzy control washing machine should be equipped with water level sensor, cloth quantity sensor, cloth quality sensor, temperature sensor and dirt sensor. However, due to the limitation of urban water quality in China (the accuracy of interference detection of components in water), at present, almost all fuzzy control washing machines produced and sold in China (whether state-owned well-known brands or joint venture brands) are not equipped with pollution sensors. So it is impossible to judge whether the clothes are washed or not. In this sense, it seems that there is still a distance between the fuzzy control washing machine in the domestic market and the fuzzy control in the real scientific sense.

As for some fully automatic drum shell washing machines with pulsators, the water level (how much water is injected), washing time, water flow intensity (such as forced washing, standard washing and mild washing) and dehydration time must be set manually in advance, which obviously cannot be called fuzzy control washing machines. At best, it is called microcomputer-controlled automatic washing machine.

2? The pulsator drum type has its own merits.

The performance of automatic washing machine mainly depends on its washing effect, including washing performance (cleanliness), fabric wear rate (clothes breakage rate), rinsing performance (rinsing rate) and so on. At present, there are three kinds of automatic washing machines: drum type, stirring type and pulsator type. Details are as follows:

1 Drum, commonly known as European style, is popular in Europe and South America. On the horizontal axis, the ribs of the inner cylinder are used as power to drive the clothes to rotate back and forth, and the clothes are lifted and slapped. Washing clothes requires hot water, which consumes a lot of electricity and has a low rate of clothes breakage. If you wash clothes with cold water, it will affect the cleanliness.

Mixing, commonly known as American, is popular in America. The vertical shaft and stirring blades are used as power to drive the clothes to swing back and forth (less than 270) and rub against each other. Because the bottom of the washing tub does not rotate, the performance such as cleanliness and clothing loss rate is in the middle.

3. The pulsator, commonly known as Japanese style, is popular in Japan, China, Southeast Asia and other regions. The pulsator at the bottom of the washing tub drives the clothes to rotate back and forth (the pulsator rotates more than 360 in standard washing). Because of the high mutual friction, wet clothes are pressed on the high-speed rotating impeller, so the clothes loss rate is high, the washing uniformity is poor and the winding rate is high.

China National Household Appliances Testing Center compares the performances of the above three washing machines with scientific experimental methods, as shown in Table 1. From the table 1, it is not difficult to see that the advantages and disadvantages of pulsator and drum are obviously compared, and their respective performances are just the opposite. The mixing type is moderate and the comprehensive performance is good.

Obviously, all kinds of washing machines have their own advantages and disadvantages. The absolute description of which must be good and which must be bad is not objective. At present, in the market of China, pulsators are the main products, supplemented by rollers. The former is difficult to be replaced in the near future because of its advantages of high cleanliness, low price (about 70% of drum type) and small area.

3? The use cost consists of two parts.

The operating cost of washing machine consists of two parts, namely, water consumption and electricity consumption. Generally speaking, the water consumption of standard washing procedures is usually indicated in the instruction manual. For a washing machine with the same washing capacity (e.g. 5.0kg), the smaller the water consumption, the better. Consciously choosing a water-saving washing machine is not only to save daily expenses, but also to contribute to environmental protection.

Another part of the use cost is power consumption. At present, because the washing machine manufacturers do not provide the power consumption for completing a washing procedure, it is difficult for consumers to calculate when purchasing. But at the consumer's home, the actual power consumption of the first washing procedure can be read by the watt-hour meter when using it.

4? Green is different from the concept of health.

At present, the popular washing machines, no matter what form, have a common shortcoming, that is, they need to use detergent. The environmental pollution caused by the discharge of phosphorus-containing washing liquid has attracted people's attention. Because phosphorus-containing washing liquid is discharged into rivers, lakes and seas, it is easy to produce phosphorus compounds, which will not only make algae in water grow rapidly, thus affecting the survival of fish, but also make lakes stink and destroy the ecological environment. Therefore, developed countries have been researching, developing and producing environmentally friendly washing machines, also known as green washing machines, that is, washing machines that do not need to use detergents. Of course, the best solution is to wash clothes without detergent, which is also a hot spot in foreign research.

Detergents are not only harmful to the environment, but also have a direct impact on the human body. The residue of various detergents on clothes can cause various skin diseases. In order to change this situation, some domestic enterprises are also trying to develop green washing machines. Some brands claim to have produced healthy washing machines, but they still use detergents to wash clothes. According to the manufacturer's self-introduction, the detergent residue on clothes can be reduced, but by how much? Does it really work? It has yet to be confirmed by scientific experiments. Because the amount of residue is related to many factors such as washing method and detergent input, it is not determined by the washing machine itself. Each brand can only compare and comment on the detergent residue before and after the improvement of its washing machine. Scientific comparison should be based on quantitative technical indicators, rather than relying solely on qualitative theoretical inference.

As far as consumers are concerned, no matter what kind of washing machine they choose or have used, the best way to reduce the harm of detergent is to put detergent in accordance with the requirements of the instruction manual of detergent, or set up a washing program that can be rinsed by themselves. For example, choosing a high water level rinse can reduce the concentration of detergent, or setting an extra rinse program can reduce the detergent residue on clothes.

5? Slimming washing machine is not conducive to washing clothes.

In order to adapt to the living situation that the bathrooms (rooms) of most urban residents in China are too small and the doors are relatively narrow, some washing machine manufacturers have developed and produced so-called thin impeller automatic drum washing machines and narrow drum washing machines. In this way, although the washing machine can enter the door (bathroom) and the space can accommodate the washing machine, another problem is exposed. That is, the washing performance decreases after the washing space is too small, and the user complains that the clothes are not clean. At least it can be seen intuitively that when washing clothes with rated capacity, it is difficult for the washed clothes to roll up and down in the washing bucket. The crux of the problem is that after this slimming design, the number of washing tanks has also decreased accordingly.

The washing clothes of the pulsator washing machine are driven by the bottom pulsator to rotate forward and backward (more than 360 in the standard washing mode). Because of the great friction between them, wet clothes are pressed on the impeller running at high speed, so the washing performance is higher than other drum-type and stirring washing machines, but the washing uniformity is poor and the winding rate is high. It is precisely for this reason that the space of the inner cylinder (that is, the space of the washing cylinder) must not be reduced. If the washing tub is small, it will be more difficult for the clothes to roll up and down. Only the part pressed on the pulsator has washing effect, and the other parts can't be washed clean. Usually, when we wash clothes, we seldom fill the washing capacity, and even fewer people put it into the washing after measuring it with a scale, so this problem is not easy to find. Families usually wash large items, but only those things that are not very dirty, such as sheets and quilts, and only some dust is washed away. But once we put enough capacity, or put more stolen clothes to wash, the problem will soon be exposed. If one or two clothes are not hydrophilic because of the fabric, it will be more difficult to wash the whole bucket of clothes.

Another unsatisfactory aspect of slimming washing machine is that the structure of the machine is too compact in space due to the blind emphasis on slimming, which leads to increased noise and vibration, and also makes washing machine consumers feel headache and trouble.

6? Clothes should be washed in a certain way.

Many people think that washing clothes with a washing machine is not my decision, and I can only obey the machine. Actually, it's not. It's not a misunderstanding, but it's still exquisite. Experiments by authoritative experimental institutions have confirmed that the following points cannot be ignored in order to improve the cleaning rate.

1 washing capacity margin

When the actual washing capacity of the pulsator washing machine is 80% of the rated capacity (for example, the capacity of 5kg is 4 kg); When the drum type is 60% (5kg capacity puts 3kg), the washing effect is the best, but if you want to wash the capacity at one time, the effect is poor.

2 the washing temperature should be appropriate.

Most concentrated detergents contain enzymes, but because of the high density and heavy proportion after concentration, they are easy to sink to the bottom of washing liquid. In order to dissolve it and make full use of the enzyme, it is best to wash it with warm water. The optimum water temperature is about 30℃ ~ 40℃.

3 soaking time can't be saved

In order to give full play to the role of surfactant in detergent, it is best to soak clothes in washing solution 10 ~ 20 minutes before washing, so that stains can be easily removed. Also, the detergent should be dissolved in water first to prevent the fluorescent agent from fading due to direct contact with clothes.

Too much detergent can't be washed clean

The washing program of pulsator automatic washing machine is automatically set by microcomputer, usually 1 time, twice rinsing, 1 time dehydration. If you put too much detergent, you can't clean it even if you rinse it twice. At present, the washing machines on the market, including fuzzy control washing machines imitating artificial intelligence, can't automatically detect whether they have been washed (due to the limitation of water quality in cities in China, such sensors can't be installed). So you can't put more detergent.

5 Overtime washing clothes damages clothes

After washing for more than a certain time (usually 10 ~ 15 minutes), the washing speed will not increase obviously, but it will damage the clothes. For example, the more popular pulsator automatic washing machine relies on the bottom pulsator to drive the clothes to rotate forward and backward (above 360) in the washing process, and the friction between them is great. Wet clothes rub on the high-speed rotating impeller, which is harmful to fabric fibers.

The concept of washing should be changed.

Develop good laundry habits and change clothes from "washing when dirty" to "washing when worn". This makes the clothes easier to wash. Dirty clothes are difficult to wash, and they are hardly washed, which is harmful to clothes.

7? What are the safety protection functions of microcomputer-controlled automatic washing machine?

At present, there are no fewer than ten kinds of fully automatic washing machines, whether controlled by microcomputer or fuzzy control. Although the software and hardware are different, the technology is mostly imported from abroad, the control principle is similar, and the specific design, circuit and program are the same. Basically at the same technical level. It is only slightly different in appearance, function key name and material selection of inner and outer cylinders. As far as the complete protection function of automatic washing machine is concerned, as long as it is a household appliance controlled by microcomputer, it generally has this function. This paper introduces the safety protection function and reminding mode of microcomputer-controlled automatic washing machine. For a specific model of a specific brand, it depends on its control level or most of it; Or just a small part of it, but some essential safety protection functions are possessed by all automatic washing machines.

1 Water inflow overtime protection function

During the water inlet process of the washing machine, due to the low water inlet pressure, impurities blocked the filter screen of the water inlet pipe connection interface, and the water inlet time was too long. At this time, in order to prevent the water inlet valve coil from burning or igniting a fire accident for a long time, in the fully automatic washing machine controlled by microcomputer, when the water inlet time exceeds 15 minutes (30 minutes for a long time) and the water level still does not reach the predetermined (selected) water level, the microcomputer will issue an instruction to close the water inlet valve coil and stop the water inlet action of the washing machine. Usually, special symbols will be displayed on the operation key panel, or music will be played at the same time, or the buzzer will sound to remind the washing machine consumers that there is something wrong with the water in your washing machine.

2 Drainage overtime protection function

The drainage of the washing machine is generally through the suction of the drainage motor or electromagnet to pull the drainage valve to open, so that the water in the washing drum flows out of the drum. Sometimes the washing machine has poor drainage or poor drainage because the drain pipe is not put down, or because the position of the drain is too high, because the drain pipe is blocked by foreign objects, or because the ice is blocked. However, if the drainage time is a little longer, the microcomputer will also issue a command to stop the drainage, so as to avoid the drainage motor or electromagnet coil being burned out after being electrified for a long time. Usually, in a fully automatic microcomputer-controlled washing machine, if the drainage does not drop to a certain level within 3-6 minutes after starting, the drainage overtime protection function will act. At the same time of music reminder or buzzer alarm, there are usually specific symbols displayed on the digital tube or fluorescent screen, or the display of light-emitting diodes at specific positions to express the information of this drainage timeout.

3 dehydration imbalance protection function

During the dehydration process of washing machine, there will be a serious imbalance phenomenon because of the deviation of washed clothes. Vibration, noise and collision caused by powerful inertial centrifugal force will damage the washing machine itself or related components. So once the vibration amplitude is too large, the microcomputer of fuzzy control washing machine will first instruct the machine to automatically correct the deviation 1 to 3 times. When the automatic rectification fails, the microcomputer will display a specific symbol or beep through the operation panel to remind the washing machine consumers to rectify manually. After rectification, close the machine cover 10 ~ 20 seconds, and the machine will enter dehydration operation again. If the automatic rectification fails, the washing machine cannot enter the normal operation of other programs until the manual rectification is completed. At this time, if the washing machine consumer happens to be out of the scene and can't intervene, the microcomputer will automatically cut off the power supply of the washing machine after maintaining this situation for a few minutes (up to 20 minutes) to protect the machine from damage.

4 dehydration and cover opening safety protection function

In order to prevent hands from being injured and clothes from being thrown out of the dewatering bucket during the rotation of the high-speed washing machine, once the upper cover of the washing machine is opened during the dehydration process, the rotating drum must be slowed down or stopped. According to GB4706.26-9 1+0 related national standard "Special Requirements for Centrifugal Dehydrators", when the washing machine is dehydrated, after the cover or door is opened for 50mm, the rotating speed of the dehydration drum should be reduced to ordinary washing or lower within 7 seconds. Therefore, if the cover is accidentally opened when the microcomputer controls the automatic washing machine to dehydrate, the dehydration will stop immediately, and at the same time, the corresponding symbol or buzzer will be displayed to remind the washing machine consumers. Similarly, if the consumer forgets to close the lid, the machine will run to the dehydration program, and the microcomputer will also issue an instruction to stop the next dehydration operation and give an alarm.

5 overvoltage and undervoltage protection function

Generally, the voltage fluctuates within the range of 200 V 10%, and the washing machine should be able to operate normally. But at present, the washing machine can work normally when the voltage exceeds 10%, but it will affect the normal operation if it exceeds the range too much. In order to protect the machine or related components from damage, some automatic washing machines will automatically cut off the power supply when the extreme undervoltage reaches 174V and the extreme overvoltage exceeds 260V to protect the machine from damage.

6 Motor overheating protection function

When the main motor of washing machine is working, the temperature rise will be too high for various reasons. At this time, the built-in automatic reset overheat protector of the main motor will act to protect the main motor from damage. Normally, the working temperature of the main motor protector is 120℃ ~ 135℃, and the recovery temperature is 85℃ ~ 95℃.

7 shutdown automatic power-off protection function

When the washing machine completes the washing procedure, it will generally play music or beep to remind the washing machine consumers. However, if consumers leave the scene and can't cut off the power supply, the washing machine controlled by microcomputer will usually automatically cut off the power supply of the executive parts within 3 to 5 minutes to avoid accidental damage of these parts due to long-term power supply.

In addition, the microcomputer automatic washing machine with high control level not only has the above safety protection function, but also has the protection performance of preventing instantaneous pulse interference and instantaneous power failure. Because the microcomputer of automatic washing machine may encounter some electromagnetic interference at any time during operation, such as the lighting process of energy-saving lamps, lightning strikes, etc., which will cause the program of washing machine to be disordered, resulting in misoperation and undue machine damage. Therefore, the control circuit of microcomputer-controlled automatic washing machine generally has anti-interference safety protection performance.

In addition, when the power grid circuit suddenly loses power for various reasons, such as the power outage time is about 50 microseconds, some microcomputer control circuits of the automatic washing machine have the performance of restoring the washing machine to the original running program and continuing to work.

Knowing these safety protection functions of microcomputer automatic washing machine, washing machine consumers don't have to panic when they see all kinds of inexplicable symbols or hear buzzer alarm during the process of using washing machine, and they are eager to call maintenance service personnel for home service. Because it is entirely possible that all kinds of safety protection measures and reminder functions appear during the operation of the washing machine are playing a role.

8? How to diagnose the fault of automatic washing machine controlled by microcomputer?

Not only washing machines, but also all household appliances controlled by microcomputers are generally designed with fault self-diagnosis function. This paper introduces the fault self-diagnosis function of microcomputer-controlled automatic washing machine. Depending on the design of the control chip or matching device, a certain model of a certain brand has most or only a small part as discussed below.

The method of fault self-diagnosis function is to display some English letters or letter combinations (used in the operation panel of digital tube or fluorescent screen) by touching the keys in sequence, or to indicate which part or component of household appliances is faulty by using different flashing positions and flashing frequencies of light-emitting diodes.

Taking a microcomputer fuzzy control automatic washing machine with a washing capacity of 4.5kg of a joint venture brand in Shanghai as an example, this paper explains the test method of fault self-diagnosis program, which parts can be detected from the test method and the types of faults.

Figure 1 is a schematic diagram of the operation key panel of the washing machine. The dots on the left of the four membrane switch buttons, such as program selection, function selection, water level and appointment, are red light-emitting diodes (LEDs). As long as this function is selected, the LED indicator corresponding to this key will light up.

Fig. 2 is a flowchart of the washing machine test program. The four horizontal columns are "Confirm Load", "Panel Display", "Test Procedure" and "Fault Diagnosis" from left to right. Take the third column "test program" as an example to explain the operation method of fault self-check program. The third column * * * has three kinds of geometric boxes from top to bottom: the text in the rounded box explains the manual operation of the inspector; The words in the prismatic and rectangular boxes explain the actions of the washing machine after receiving the manual operation instructions. The difference is that the prism frame is a discrimination frame. Rectangular boxes are non-discriminatory boxes. From the horizontal side to the left side of each block diagram, the corresponding text in the "Panel Display" and "Confirm Load" columns explains the prompt content respectively. Now take the lighting of standard, immersion, quick wash and soft lights in the first box of the panel display column as an example. In fact, this refers to the moment when the washing machine is powered on and ready for water supply and drainage. Before the water supply starts, press the test key according to the requirements in the first round box. The LED light on the left side of the corresponding four program selection names lights up. The corresponding "water inlet valve" in the column of "confirmed load" refers to the name of the faulty component that may occur during the test procedure in this step, that is, the occurrence of the fault may be related to this component. But what is the cause? You can check the specific analysis content indicated in the fault diagnosis table (no water inflow) in the corresponding "fault diagnosis" column.

The fault self-diagnosis function is generally provided for maintenance personnel to repair the faults of washing machines (see Table 2). However, some brands of washing machines also indicate the fault self-diagnosis (or self-calibration) procedure in the product instruction manual of the washing machine. Therefore, when there are all kinds of inexplicable symbols or buzzer alarms in the washing machine, consumers of the washing machine don't have to panic and hurriedly call the maintenance service personnel for home service. You can also check what is wrong with the washing machine through the fault self-diagnosis (self-calibration) program. For those faults that are not caused by the damage of the components of the washing machine itself, such as delayed water intake and drainage, overvoltage and undervoltage, it is better to find out the reasons first and then eliminate them yourself. Because, from the future development trend, some intelligent household appliances controlled by microcomputer will have universal fault self-diagnosis function and simple troubleshooting methods to give tips. With the acceleration of the pace of life, it is not cost-effective to take time off and wait for the maintenance service personnel to come to the door to eliminate the faults that are easy to lift a finger, from the point of view that time is money. ▲