Vehicle air purifier control board development

Existing studies have shown that compared with the urban air pollution, the air pollution in the car is more serious. Various harmful gases such as benzene and formaldehyde produced by the interior decoration of the car are mixed with the air in the car, causing serious damage to the body of the passengers. Serious hazard to health. Moreover, because the environment inside the car is usually relatively humid and warm, it is very easy to produce a lot of bacteria, which further deteriorates the air environment inside the car. This will not only affect the physical and mental health of passengers, but also make the drivers prone to fatigue. Thereby causing bigger driving safety hidden danger. In view of this, it is necessary to actively take scientific and effective preventive measures to sort out and study the current mainstream vehicle air purifier technology, and point out the future development direction of vehicle air purifiers.

1. Development background of vehicle air purifiers in my country

According to my country's air quality survey statistics in 2013, among the more than 70 key cities with rapid economic development in my country, the air pollution index of about 67 cities has exceeded the standard, and the proportion of the number of cities exceeding the standard is 96%. In these cities where the pollution level seriously exceeds the standard, the main air pollutant is PM2.5. As the concentration of PH2.5 in the air continues to increase, the chances of people dying from heart and lung diseases also increase greatly, and the PH2.5 It will also cause a large range of smog, causing serious harm to people's health and immunity. Today, as the urban air environment is deteriorating, more and more people choose to travel by car. Therefore, the number of cars in my country has shown a trend of increasing year by year in recent years. The leather and plastic decorations in the car will emit harmful and toxic substances such as formaldehyde and benzene. Especially for new cars just purchased, the concentration of formaldehyde in the car will far exceed that of cars with a long service life. Severe urban air pollution and pollution caused by car interior decorations have a great impact on the air in the car, because the car purifier can filter out harmful gases such as formaldehyde and PH2.5 in the air to a large extent, so It has achieved great development and application, and because of its healthy and environmentally friendly functions and concepts, it has further promoted people's market demand for car air purifiers.

2. Analysis of Mainstream Technology of Car Air Purifier

(1) Normal temperature formaldehyde catalytic oxidation technology: The principle of normal temperature formaldehyde catalytic oxidation technology is to use metal carbonate or metal nitrate to oxidize and precipitate to obtain metal oxides, and to load a small amount of metal oxides on the formed metal oxides. For precious metals such as europium gold, at room temperature, europium gold will undergo a catalytic oxidation reaction with formaldehyde to produce moisture and CO2. The use of room temperature formaldehyde catalytic oxidation technology can effectively convert formaldehyde gas in the car into water and CO2, and the air purification efficiency is relatively high, and the purification module can be used permanently.

(2) Electrostatic dust removal technology: The main working principle of electrostatic dust removal technology is to ionize the gas in the high-voltage electrostatic field, so that the charged dust particles are gradually deposited on the surface of the anode, thereby purifying the air. Since the electrostatic car air purifier can only deal with air impurities such as bacteria and dust in the car, it cannot effectively decompose the toxic and harmful chemical gases in the car, and cannot eliminate the peculiar smell in the car, so it can be achieved better with other equipment. The air purification effect in the car. Moreover, when using electrostatic dust removal technology to purify the air in the car, when the number of suspended particles in the car increases, the purification effect will be greatly reduced.

(3) Filter adsorption technology: The main principle of filter adsorption technology is to use the glass fiber material or mesh structure plastic to throttle the particulate matter in the air on its surface, so as to purify the air, which is usually more commonly used There are three types of filters: activated carbon filter, primary filter and HEPA filter. The car air purifier made of filter adsorption technology can effectively remove bacteria, benzene, formaldehyde and other harmful substances in the car. However, because the service life of the filter screen is limited, and the power of this type of vehicle-mounted air purifier is generally small, there is not enough fan power, so the air in the vehicle cannot be thoroughly purified.

(4) Ozone sterilization and decomposition technology: Compared with other vehicle-mounted air purifier air purification technologies, ozone sterilization and decomposition technology has a very strong sterilization effect. Because ozone is a strong oxidant, it has a very strong oxidizing ability, especially the oxidation effect on bacteria, nicotine and amine is very prominent. In addition, ozone can also oxidize and decompose benzene, VOC, etc. However, the use of ozone sterilization and decomposition technology to purify the air in the car also has certain limitations, because ozone is a gas that is harmful to the human body, and the country has very strict requirements for its use. Therefore, when using an ozone car air purifier, you must ensure that No one was in the car.

(5) Negative ion technology: Negative ions have a certain charge, which can cause tiny dust particles in the air to coalesce together to form larger particles and settle, thereby purifying the air. In addition, when negative ions are ionized, a very small amount of ozone will be generated in the air, which can kill all kinds of microorganisms and bacteria mixed in the air, so that the air becomes more fresh and refreshing, which is beneficial to the improvement of the human body. Immunity is very beneficial. The purification effect of the car air purifier made of negative ion technology is very significant, but it also has obvious disadvantages, that is, when its concentration is high, it will have certain side effects on the human body, and it will affect the formaldehyde and VOC in the air in the car. The decomposition effect of impurities is not obvious.

(6) Nano-photocatalyst technology: Nano-photocatalyst technology is an air purification technology that has only emerged in recent years. Vehicle-mounted air purifiers made of this technology are usually also called ultraviolet light-vehicle air purifiers. The irradiation effect kills all kinds of microorganisms and bacteria in the air in the car, so as to achieve the effect of disinfection and sterilization. Generally speaking, the ultraviolet light car air purifier integrates nano photocatalyst technology, negative ion technology, etc., which has the remarkable advantage of thorough sterilization.

3. Development trend of vehicle-mounted air purifiers

Through in-depth research, it can be known that the future development trend of vehicle air purifiers is mainly reflected in two aspects of intelligence and Internetization. The details are as follows:

(1) Intelligentization of car air purifiers. Due to the constraints of its own hardware conditions, traditional car air purifiers are not satisfactory in terms of algorithm processing and human-computer interaction capabilities. In the future, with the continuous improvement of intelligent hardware and the gradual popularization of short-distance communication technology, people can bind all the data of the car air purifier with the mobile phone, and then people can use the mobile phone to monitor and purify the car air purifier. Data is tracked and controlled. In the process of intelligentization of vehicle-mounted air purifiers, how to effectively realize the stable transmission of interactive data by short-distance wireless communication technology is the key link.

(2) Internetization of car air purifiers. In the process of gradually promoting the intelligence of car air purifiers in the future, mobile phones, as Internet products, will inevitably drive car air purifiers to develop towards the Internet. In addition to realizing the function of tracking and controlling various monitoring data of vehicle-mounted air purifiers using Internet mobile phones, more abundant and diversified Internet-based services will inevitably be derived, for example, combining the characteristics of pollutants in vehicles to push air cleaning for users Drug advertisements, etc.

With the increase in the popularity of automobiles in households in my country, attention has been paid to the impact of dust, volatile organic compounds in automobiles, and air pollutants entering from the air inlet of automobile air conditioners on the human body. Moreover, the interior of the car is relatively closed, which will lead to excessive exhaust gas volume and insufficient oxygen supply in a small area, which will easily cause the driver's inability to concentrate and fatigue. Being in this environment for a long time will pose a health threat to the human body. Most of the existing car air purifiers are evolved from filter-type household purifiers, which are usually small and exquisite, and are placed in the car. Although this kind of purifier can effectively purify harmful substances such as bacteria and dust, but because of its small size, the product has few functions and low purification efficiency.

4. Hardware design of vehicle purifier control system

This design takes the STC15W401AS single-chip microcomputer as the core, and combines temperature and humidity sensors, ozone purifiers, electrostatic precipitators, negative ion purifiers and humidification devices to design a car air purifier. The hardware part adopts modular design, and relays are used to control the opening and closing of each module.

The system adopts STC15W401AS single-chip microcomputer, the single-chip microcomputer adopts 8051 core, it has 2K bytes storage space, has two independent serial ports, has high-speed 10-bit converter, 8-channel, high-speed and reliable. This MCU belongs to 1T MCU, which is 8 to 12 times faster than traditional 12T MCU. The processor is adopted to meet the requirements of low cost, high speed and good reliability.

4.1 Power conversion module

Since the rated operating voltage of the STC15W401AS microcontroller is 3.3V, the relay needs 5V DC power supply at the same time. Therefore, the power conversion module uses LM2576, which converts the 12V DC voltage of the car into 3.3V and 5V DC through LM2576, and provides them to the microcontroller and relays after filtering.

LM2576 is a commonly used voltage regulator chip, its maximum current can reach 3A, which is fully capable of driving the relay to work. LM2576 can produce high reliability microcontroller power supply. Therefore, by adopting two types of voltage regulator chips of 3.3V and 5V, the power supply demand of the system can be met.

4.2 Temperature and humidity sensor module

DHT11 is a commonly used temperature and humidity detection module. DHT11 integrates control and calibration circuits inside, and does not require any other external components. At the same time, DHT11 has been calibrated in an accurate humidity calibration room, and does not need to be calibrated during use, which simplifies the process of making a car air purifier. It can be seen that DHT11 has very good stability and reliability, and is very suitable for this control system.

The DATA pin in DHT11 is used as a serial bus to communicate with the single-chip microcomputer. In order to solve the problem of insufficient driving ability of the single-chip microcomputer pin, a 4.7k pull-up resistor is used as compensation.

4.3 Relay driver module

The relay is connected to the I/O output of the single-chip microcomputer through the SN7404N, and the single-chip microcomputer output command controls the opening and closing of the relay, and then controls the opening and closing of each working module. The setting of SN7404N plays an isolation role, which can effectively protect the microcontroller and prevent the chip from being accidentally burned.

5. Software design of vehicle air purifier control system

In order to achieve the effect of updating, purifying and dust-removing the air in the car, it is necessary to let the main program realize the cycle work of ventilation, ozone sterilization, negative ions and electrostatic dust removal. And in order to meet the comfort in the car, it is necessary to meet the free settings of the people in the car, such as the wind speed and humidity of the air supply.

After the air purifier is turned on, wait for the automatic mode or manual mode to be selected. If the automatic mode is selected, the machine waits for manual input parameters, such as wind speed, humidity and temperature requirements. After waiting for the parameters to be loaded, the purifier completes humidification and other work based on the data collected by the temperature and humidity sensor DHT11. When performing ventilation work, the ozone sterilization module and electrostatic dust removal module are used to ensure that the air entering the car is clean and fresh. After that, in the process of small air circulation in the car, the function of dust removal and purification is continuously performed. After completing the entire working state, check and compare the parameters. If the parameters are not updated, it means that the purifier has completed the initial preset, and the entire program can be ended. If the parameters are updated, the parameters will be reloaded, and functions such as ventilation and purification will continue to be performed.

If you choose the manual mode, the machine waits for the user's settings, such as the size of the air supply, the degree of humidification, etc., until the user turns it off, and keeps the setting state.

Summarize

The system control design of the car air purifier is based on the STC15W401AS series microcontroller, which has the advantages of stable operation and low cost. Through the cooperation of multiple modules, it can realize the functions of updating, purifying, dedusting, sterilizing and humidifying the air in the car. It has the advantages of powerful functions and can provide a good environment for the car. In addition, the design of the system is user-friendly, the parameters are set by the user, and the wind speed, temperature and humidity are all adjustable. There are manual and automatic modes to choose from for users to adjust by themselves. If the automatic mode is selected, it can automatically complete the purification of the air in the car and the air entering the car, which can not only reduce outdoor pollution gases and bacteria from entering the car, but also realize self-circulation and purification in the car. This is a function that most car air purifiers do not have. The system adopts modular design, and more functions can be realized by adding modules. For example, after adding an independent power supply, it can continue to work after the car is turned off, and prevent fire problems caused by excessive temperature in the car in summer through ventilation.

The above is the development example of the car air purifier introduced by Shenzhen Zuchuang Microelectronics Co., Ltd. for you. If you have car purifier control panel design requirements, you can trust us. We represent a variety of single-chip microcomputers, voice chips, dual-mode Bluetooth ICs, and wifi chips. Brands include Songhan MCU, Yingguang MCU, Jerry Bluetooth, Ankai Bluetooth, Allwinner, and Realtek. Our technical services include: PCB design, microcontroller development, Bluetooth solutions, software and hardware custom development, APP development, small program development, WeChat official account development, etc. It can also undertake the design of intelligent electronic products, the development of living appliances, the research and development of beauty equipment, the application of Internet of things platform, the smart home control system, the development of TWS earphones, Bluetooth earphone speakers, the development of children's educational toys, the design of electronic education products, etc.