Introduction The airbag is an auxiliary protection device for the airbag system. It is made of special nylon with rubber lining and is filled with harmless helium during work. In the event of a collision, the airbag inflates in approximately 0.03 seconds. The very fast inflation speed ensures that the airbags arrive in time when the passenger's body is constrained by the seat belt and the head is still moving forward. When the head hits the airbag, the airbag starts to exhaust through the air hole on the airbag surface. The discharge of gas has a certain rate to ensure that people's body parts slowly decelerate. Because the speed of the air bag to inflate and inflate can reach up to 320 km/h, if the person's posture is incorrect during a collision, it will cause serious injuries.
Classification According to the object of protection â— Front airbag: Driver Airbag (DA), Passenger Airbag (Passenger Front Airbag; PA)
Side airbags: Front Side Airbag (FSA), Rear Side Airbag (RSA)
â—Side Air Curtains â—Knee Airbags are divided by the number of single airbags and double airbags The number of airbags that are currently standard in mid- and low-end cars produced in China is 1-2, which are generally one in each of the driving and co-pilot positions of the vehicle. It is used to protect the front row members from effective protection of the chest and brain in the event of a violent impact on the vehicle.
Four airbags In some mid-range B-class cars, four airbags are generally installed in addition to two in the driving and front passenger seats, and two in its side door.
Multi-airbags are known for safety in some high-end cars. Sweden’s Volvo sedan is equipped with 6 airbags and 18 air curtains in its flagship model, which are located in the front and front passenger compartments of the vehicle, on both sides of the front and rear doors. Each of the two, 18 air curtains are located at the front and rear windshields and at the side windows, providing the most effective protection against impact from all directions.
Split air bag type safety belt according to innovation
The airbag-type seat belts that prevent automobile rebound and cause casualties are also called airbag-type seat belts. In the shoulder and the whole of the car belt, there is a peg-shaped airbag device. The belt combines the characteristics of conventional seat belts and airbags to provide passengers with a higher level of crash safety protection. This technology reduces injuries to the passenger's head, neck and chest during an accident. The use of airbag-type seat belts further enhances the vehicle's safety and innovation facilities, and it is a boon to children and the elderly.
This airbag type seat belt, when it comes to accidents, the seat belt will instantly expand into a balloon-like, its impact relief effect is 5 times that of the traditional seat belt; First, large area can effectively reduce the head and neck Shaking, and second, when the airbag inflates, it has a certain reaction force, which can reduce the phenomenon of rib fractures, internal organs damage and bruises that are likely to occur to passengers during accidents, and avoids the accidental injury of more than 60% of cervical vertebrae due to airbags.
The side airbag side airbag is mounted on the outside of the seat in order to mitigate the side impact. Nowadays, many manufacturers' models are equipped with standard side airbags for the front two seats, while the rear-mounted side airbags are rarely equipped.
Most knee airbags are equipped only with main and co-pilot airbags, side airbags, etc. In fact, when the vehicle actually encounters a frontal collision, the following is more protected. The distance between the lower knee and the center console is the shortest. It is the site most likely to cause fracture damage.
The knee airbag is used to reduce the occupant's knee injury to the interior of the vehicle in a secondary collision. The airbag in the knee part is located in the front driver's seat. Once it is opened, it can effectively protect the lower body parts of the rear passengers, which can also relieve the forward momentum from the frontal collision.
The head airbag head airbag is also called a side air curtain, which pops up and covers the windows in a collision to achieve the effect of protecting the passengers.
The head airbag is mainly used to protect the head of the occupant when a side collision occurs. The B-pillar side, window glass, and even seat belt side support buckles can all be killers in a car accident. Then the head airbag will separate the members from these things.
The head airbag is installed in the curved steel reed in the roof, usually through the front and rear, controlled by the lateral acceleration sensor in the body. The detonation is controlled when the lateral acceleration is greater than normal and reaches a dangerous value. It has good personnel protection functions for serious accidents such as side collisions and rollovers.
Working principle During the driving of the vehicle, the sensor system continuously sends speed change (or acceleration) information to the control device. The control device (central controller) analyzes and judges these information, if the measured acceleration, speed change, or other indicators exceed The predetermined value (that is, the actual collision), the control device sends a firing command to the gas generator generator or the sensor directly controls the ignition, an explosive reaction occurs after ignition, N2 is generated or the compressed nitrogen in the gas tank is released to fill the collision airbag . When the occupant comes into contact with the air bag, the impact energy is absorbed by the air vent hole of the air bag to protect the occupant.
The car's airbag contains substances such as sodium azide (NaN3) and ammonium nitrate (NH4NO3).
When a car is hit hard at high speeds, these substances will quickly decompose and produce a lot of gas, filling the airbags. [Sodium azide decomposes to produce nitrogen and solid sodium, ammonium nitrate is involved as an oxidant.
The new airbag incorporates a device that can inflate or release pressure in order to prevent the huge pressure generated by a sudden burst of fire from harming the human head, especially when the passenger does not wear a seat belt. The specific forms are:
1. The stage point explosion device, ie, the gas generator is divided into two stages, the first stage generates about 40% of the gas volume, far below the maximum pressure, which has a buffer effect on the movement of the human head, and the second stage of the point explosion generates residual gas. And reach the maximum pressure. In general, the maximum pressure of a two-stage burst is less than that of a single-stage burst. In this form, the pressure gradually increases.
2. The pressure relief mode is divided, and pressure holes or pressure-adjustable holes are opened in the pouch, which can be divided into two types, namely Tether, which is completely opened by means of gas pressure or a computer-controlled pull tab. In this way, the initial pressure reaches the set limit, and then the pressure is released instantaneously to avoid excessive damage.
Opening conditions In order to ensure that the airbag is opened at the appropriate time, the automobile manufacturer has specified the conditions for the initiation of the airbag. Only if these conditions are met, the airbag will explode. Although in some traffic accidents, the occupants of the vehicle have broken their heads, or even become life-threatening, and the vehicles are nearing end-of-life. However, if the condition of the airbag explosion is not reached, the airbags will not open.
Airbag opening requires proper speed and impact angle. In theory, only when the vehicle's position is about 60° from the front of the vehicle and it strikes a stationary object at a speed higher than 30km/h, the airbag can be opened. The speed mentioned here is not the vehicle speed that we understand in the ordinary sense, but the speed of the collision of fixed obstacles in the test chamber relative to the vehicle. The speed of the car in the actual collision is higher than the test speed.
The main parts of the car when the collision occurs are the bumper and the body longitudinal beam. In order to buffer the impact force during the collision, most of the front part of the car is designed with a collision buffer, and the rigidity distribution of the vehicle body is also uneven. In some accidents, such as when a rear-end rear-end collision occurred between a sedan and a truck without a rear guard, or a roll-over accident after a collision of a sedan, or a side collision with a vehicle, such accidents are often not directly hit by the front of the vehicle body. It is mainly the collision between the upper part and the side of the car body. The rigidity of the collision part is very small. Although the car cabin has undergone a great deformation, which has caused the injury or death of the occupants in the car, due to the wrong position of the collision, sometimes the air bag cannot be opened. Especially in side impacts, if no side airbags are deployed, the main and sub airbags cannot be detonated because they cannot reach the detonation conditions. Features Advantages Airbags can distribute impact forces evenly over the head and chest, preventing fragile passengers The direct collision of the body will greatly reduce the possibility of injury. Airbags can effectively protect passengers from frontal impact. Even without a seatbelt on a smart airbag, the airbag can still effectively reduce the damage. According to statistics, when a car with an airbag is hit in a frontal collision, the degree of passenger injury can be reduced by up to 64%, and even 80% of passengers are not wearing a seat belt! As for the collision from the side and the back seat, it still depends on the function of the seat belt. In addition, the airbag burst volume is only about 130 decibels, in the human body tolerable range; 78% of the gas in the airbag is nitrogen, very stable and non-toxic, harmless to the human body; the powder that is brought out to maintain the airbag Lubricated powders that do not stick together in the folded state are also harmless to the human body.
Defective airbags also have its unsafe side. According to calculations, if the car is traveling at a speed of 60 km/h, a sudden impact will cause the vehicle to stop within 0.2 seconds, and the air bag will pop up at a speed of about 300 km/h. The resulting impact force is about 180 kg. This is difficult for the vulnerable parts of the body such as the head and neck. Therefore, if the angle and intensity of the airbag pop up are slightly wrong, it is likely to create a "tragedy."
1. The airbag may open at very low speeds. When a car is driving at a low speed and a collision occurs, the occupant and the driver can fasten the seat belt, and no airbag protection is required at all. If the airbag is deployed at this time, it will cause unnecessary waste, and may even increase the crash damage due to deployment of the airbag.
2. Initiation of airbags can cause injuries to occupants. When the airbag system is activated, the airbag cover will be flushed and the inflation will be carried out in an instant, which may cause impact to the occupant; the hot gas generated may also burn the occupant and the driver.
3. When the passenger deviates from the seat or the seat is unoccupied or the child takes a ride, the activation of the airbag system not only fails to provide the necessary protection, but also may cause some damage to the occupant.
The improved technology can be seen from the defects in the use of airbags. The basic design objective of existing airbags is to deal with serious traffic accidents. However, in some less serious accidents, the system is overreacted, and it will Passengers exert excessive effects, which are counterproductive and cause unnecessary harm.
For practical problems, we also hope that before the airbag deployment, the airbag system can accurately detect the car's collision and determine the severity of the collision according to the program. If the collision level is relatively low, only safety The pretensioning mechanism of the belt can be tightened; if the collision level is relatively high and the airbag needs to be activated, the instruction to light the airbag is transmitted to the airbag system. This also means that the airbag system is required to accurately sense the collision accident; and it can imitate the human brain, determine whether the airbag needs to be deployed according to the actual collision degree, and has certain flexibility; and can appropriately target different occupants Adjust the airbag.
Magnetoelectric sensor sensor triggers are usually: switch type, purely mechanical type, single point electronic type, side impact type, strain type and so on. At present, there is no uniform standard for sensor triggering methods for airbags in automobiles. Not only is it a wide variety of types, but also because the sensor triggering methods installed on different positions on the vehicle body are also different. In order to enable the sensor to be conveniently installed in each required sensing area, so that it can accurately and timely sense the collision, a magnetoelectric sensor can be selected.
The magnetoelectric sensor can be installed anywhere on the vehicle body, as long as some parameter values ​​are slightly adjusted, making it possible to identify collision acceleration signals with a peak value of 0588 m/s and a time pulse of 0-20 ms. As long as the collision acceleration peak and time pulse width meet the conditions at the same time, it will send a trigger signal to the airbag to deploy the airbag to protect the human body.
The sensor structure consists of a housing (non-magnetic material), magnetic material, inertial body (non-magnetic material), soft iron attached to the inertial body, a spring for supporting and adjusting the displacement amplitude, and a permanent installed in the flange connected to the housing. Magnets and coils and leads wound on soft iron. When the sensor is subjected to a collision acceleration, the inertial body generates a reverse acceleration, which results in a change in the magnetic flux passing through the coil. A bell-shaped pulse signal is generated at both ends of the coil lead. When the spring stiffness is adjusted, the width of the acceleration signal may be changed.
The signal discriminating circuit of the sensor is composed of three parts: signal amplitude discriminating circuit; signal width discriminating circuit; useful and useless signal discriminating circuit. By multi-directionally judging the collision signal, the collision signal obtained by the control device can be more comprehensive and the ignition control issued can be more accurate, thereby ensuring that the airbag is deployed under necessary conditions.
How to obtain a stable impact acceleration signal is research; the key of the sensor is also the key to ensure the sensor accurately obtains the collision signal. The magnetoelectric acceleration sensor adopts a drop-weight impact test device to adjust and correct its sensitivity to induction. When the hammerhead is released and collided with the rubber surface, the acceleration or magnetoelectric sensor mounted on the hammerhead will feel the impact acceleration. Different drop heights correspond to different accelerations; adjusting the rubber thickness can change the signal width; adjusting the drop hammer height can change the signal amplitude.
Magnetoelectric sensors not only have low error rate in the electronic identification circuit, but also have high reliability and accuracy in the induction collision signal. Moreover, the width of the sensing range can be adjusted by the calibration of the hammer to meet the recurrence of the impulse generated by the car collision, and thus can also be installed. On any part of the body. There is also its simple design, low price, and it is no longer a prohibitive luxury for most car users.
The requirement of the intelligent control system for the airbag control system is to accurately determine the crash intensity of the accident and control the deployment of the airbag. For the defects in the use of airbags, we must further improve the flexibility and accuracy of the control system. For this reason, we can adopt an intelligent control system.
1. Collision sensor. The function of the important components in the airbag system is to detect and determine the impact signal of the car after the collision in order to decide whether to open the buffer airbag. Collision sensors mainly use three types of mechanical sensors used in early airbags. The main application of inertial principle is to use the inertia force of the components in the sensor to overcome the spring force to trigger the gas generator. The mechanical type ensures that the airbag is not activated when the acceleration is low, and the reliability is high; however, only a single point of sensing is available, and the requirements for the quality, precision, and wear resistance of the mechanical parts are extremely high.
The electronic sensor is one of the earliest collision sensors used. According to the electronic principle, the electric signal is used to reflect the deceleration of the vehicle, and then it is determined based on the electric signal whether to open the buffer airbag.
Electromechanical sensors use electromechanical methods to convert mechanical signals into electronic signals and then use electronic signals to burst airbags. That is to say, it has the advantages of mechanical, but also can overcome the defects of the mechanical sensor itself, installed in any position on the body in order to get a better deceleration signal, and can install multiple sensors in the same position.
2. Buffer airbags. The airbag is generally made of polyamide fabric with good anti-cracking performance. It is a semi-rigid foam plastic that can withstand greater pressure. After vulcanization treatment, it can reduce the inertia force when the airbag is inflated; Sealed, airbag coated with coating material. The size, shape, and air leakage performance of the airbag are important factors in determining the airbag protection effect and must be determined according to the actual conditions of different automobiles.
At present, airbag system developers are developing intelligent airbag systems based on neural network principles. It mainly uses nerve endings (ie, various sensors) to transmit various information of the surrounding environment it explores to the central nervous system (ie, computer or computer), and can collide the collision type of the accident, the severity of the collision accident, and the time of collision. The information such as the speed of the vehicle is transmitted to the computer, and the computer processes and analyzes the information, responds accordingly, and executes the correct airbag protection program corresponding to the information, which is the so-called intelligent control system.
The intelligent control system generally consists of two parts, a software part and a hardware part. The hardware part mainly consists of the electronic control unit (including the SCM, sensors, ignition circuit, etc.) and the ground part (including the serial communication circuit, computer system, etc.) of the vehicle-mounted part; the software part is mainly composed of the single-chip microcomputer, the computer part and the microcomputer part. Control system block diagram shown in Figure 2. Injury to airbags, poor protection or waste.
The occupant detection system is aimed at the airbags failing to provide appropriate protection for different occupants. We can install an occupant detection system on the occupant's seat to detect whether there are people on the seat, the size of the occupants, and the deviation from the middle when seated. . Equivalent to a sensor installed specifically to detect passengers ride information and pass it to the central computer control center. If a collision occurs, the control center makes a comprehensive assessment of the occupant's ride information detected by the occupant detection system while judging the information transmitted from various sensors. In this case, the airbag system can deploy the airbags in proper and timely manner for the driver and the occupant, completely avoiding the need for an ideal airbag to protect the user of the vehicle against various special conditions. Airbags should collect and use as much data as possible about the occupant's position information, the type of crash and the speed of crashes, establish a database, identify and judge information about the occupants and cars in the collision, and adjust the safety restraint system parameters so that the human body can obtain the most Good protection. To achieve this ideal, take our current research. In fact, there may be a long gap, but we can complete it step by step. The above discussion and reflection is only a step toward the ideal. It is believed that with the development of science and technology research, our vehicle safety measures will be more perfect.
The diversification of gas generators for gas generators requires not only reliable operation, stable performance, good durability, and compliance with environmental requirements, but also requires minimizing their quality and reducing costs. Especially in the case of airbag gas injury, it is even more demanding to improve the gas generator. At present, airbag systems on automobiles employ a large number of propellant-type gas generators using azide as a gas generating material, and other types of gas generators include a mixed gas type gas generator, a liquid (liquid gas) type gas generator, and compressed air. Energy storage gas generators and nitrocellulose gas generators are also actively researched and developed. For example, a low-density, non-toxic gas-type gas generator produced by Molton Company has the advantages of small size and light weight compared with existing ones; a new type of sodium-free azide gas developed by Brad Company has occurred. The device consumes less than 40% of the sodium azide gas generating agent and can produce an equal amount of gas, thereby reducing its volume and quality.
It is to add sensors on the basis of the general type to detect whether the occupants of the seat are children or adults. How fast the seat belts and the position of the occupants are, and by collecting these data, it is analyzed by the computer software. And deal with controlling the inflation of the airbag so that it can play its best role and avoid unnecessary expansion of the airbag, thereby greatly improving its safety. Smart airbags have two more core components than the common ones, namely sensors and their associated computer software.
History of development The idea of ​​using airbags to protect car occupants was first generated in the United States. In 1952, the American Automobile Manufacturers Association theoretically elaborated on the necessity of such a car safety system. Almost at the same time, the schematic diagram of such a system was also drawn up. In August 1953, Hurtrik first proposed the "airbag protection device for automobiles" and obtained the patent for "car buffer safety device" in the United States. However, because of the technical level at the time, this idea or patent could not be implemented. In 1966, Mercedes-Benz began developing airbag devices. Mercedes engineers first invented crash sensors and gas generating devices to allow airbags to inflate in 30 milliseconds. They also developed tear-resistant airbag fabrics. Improve the airbag's expansion characteristics, and finally, the entire device design is installed in the car's steering wheel. After about 250 real-vehicle crash tests, 2,500 bench trials, and over 7 million km of vehicle road tests, in December 1980, along with pre-tensioned seat belts, airbags were installed at the time. Mercedes-Benz S-Class sedan. Since 1985, Mercedes-Benz has installed this safety system on all vehicles that supply the US market. In 1991, almost 28% of Mercedes-Benz cars were equipped with driver airbags. It has been 25 years since the Mercedes-Benz S-Class, which was the earliest to have airbags, drove off the production line. According to statistics of the National Highway Safety Administration (NHTSA) of the United States, airbags have protected about 14,200 lives in accidents in the United States. In Germany, airbags have blocked 2 500 since 1990. Examples of traffic accidents that have caused major injuries. According to statistics, airbags can protect about one-third of the personnel from surviving in a serious collision accident. In addition, one-sixth of drivers or front passengers can be rescued by airbags during a collision. The use of airbags significantly improves the passive safety of the car.
At present, many countries in the world require airbags to be installed on new cars. For example, in the United States, the corresponding regulations have been implemented since 1989. This regulation not only requires that all new vehicles must be equipped with airbags, but also that the size of the airbags be regulated. Americans think that the bigger the airbag is, the better, while European experts believe that the best solution should be the use of seatbelts and small-sized airbags. Therefore, European companies only produce small-sized airbags. Nowadays, a common arrangement in a car is that one airbag is mounted on the steering wheel, and the other is installed in front of the front passenger next to the driver. Modern airbags are made of nylon and the inner surface is coated with a layer of synthetic rubber or Silicone Rubber to ensure hermeticity. The inner surface of the airbag is fixed with special straps which keep it in shape when the airbag is inflated. The side of the airbag is provided with a plurality of holes which are used to rapidly discharge gas from the airbag to facilitate the cushioning of the impact. In order to avoid the air bags from being stacked for a long time to form a hard block, a special material is covered inside the air bag, which can make the effective service period of the air bag reach 15 years.
As the earliest manufacturer of airbags, Mercedes-Benz has so far equipped its airbags with 12 million vehicles. In 1992, airbags were already a standard configuration for Mercedes-Benz cars. In recent years, Mercedes' engineers are still working on technologies for improving airbags, including side airbag systems and airbag control systems that can respond better in an accident.
The use of airbags significantly improves the passive safety of the car. According to statistics, due to the widespread use of airbags in North America, the accidental death rate has decreased by 12%, and the degree of injury to the human body has also been reduced under the protection of airbags. However, the automotive airbag system also has an astonishingly damaging negative effect, of which the most important one is twofold. On the one hand, the traditional frontal collision airbag system is designed based on the conventional seating position and posture of the front seat occupant and the ideal ignition timing of the airbag. However, in the actual automobile collision accident, there are many factors that affect the protection effect of the airbag, such as the occupant. The height and weight, the position of the occupant relative to the steering wheel or dashboard, the severity of the collision, etc., different collision conditions and changes in the position of the occupant will result in the occupant not being in contact with the airbag at the optimum moment. This reduces the protective effect on the occupants and sometimes hurts the life of the occupants.
On the other hand, although the quality of airbags made of nylon or polyester fabrics is not large, the instantaneous deployment speed is as high as 200km/h or more. This impact speed is not a small number for the human body, according to the US National Highway. According to the statistics of the safety management department, while airbags saved 100 lives during a collision accident, unfortunately, 57 occupants lost their lives due to improper deployment of airbags and improper seating and sitting positions of occupants. In the next few years, airbags will still play an important role in car safety equipment. The possibility that engineers are looking for an active safety system that can automatically adjust to possible accidents and car drivers, the development of new intelligent airbags puts higher requirements on new technologies. Due to the way the airbag is used, the impact caused by the blasting force has some harm to the human body. When the distance between the driver and the steering wheel airbag liner is less than 10cm, the airbag exploded in 20-30ms will give the driver a fatal impact injury. However, if the members of the front passenger seat do not maintain a proper sitting posture, the possibility of causing injuries in the collision will also greatly increase.
At present, there are two trends in the development of airbags. Automobile companies in the United States and Japan are trying to increase the size of airbags to protect occupants. And some European automobile manufacturing companies, such as Mercedes-Benz, BMW and Volvo, believe that the airbag itself is by no means a guarantee for the occupant's panacea. It must be effective in a unified passive safety system for cars. In this system, certain Should be equipped with a constricted seat belt, a seat with a reliable structure, a seat for children and a series of other components. Moreover, it is best to consider the installation of all necessary components of the safety system at the beginning of the design of the body structure.
Now, in Mercedes-Benz's PRE-SAFE pre-warning safety system, the airbag, as its main part, is controlled by an early warning sensor. The airbag can be deployed before the collision begins and it can better cushion the collision energy during the collision. The PRE-SAFE pre-alarm safety system further enhances the protection effect of the seat belt and the airbag. The warning device can judge the impending accident and adjust the seat and pretension the seat belt when there is a possibility of collision. , so that the passengers in the car get the best protection in the collision, even in the moment of collision early detonation of airbags, so that the impact of the buffer capacity to achieve the best.
The intelligent development of airbags in the future also includes the integration of advanced sensor technologies and information processing systems, which can provide reliable information on collision environment during the short time of an accident. This information includes the severity of the car crash, the form of the collision (positive or side-impact, etc.), the occupant's size, weight, seating position and riding posture, and whether the occupant is wearing a seat belt. Based on the detected information, the intelligent airbag system calculates and analyzes the electronic control system to determine when and how much the airbag deploys, thus providing the occupant with optimal protection.
Both Siemens of Germany and Jaguar of the United Kingdom have developed a management system that can control the detonation of air bags based on collision environment information. Siemens uses three-dimensional cameras and weight sensors in seats to identify the position and sitting position of occupants sitting in each seat in the vehicle, while Jaguar uses the Adaptive Constraint Technology System (ARTS) on each of its xK series models. The system uses ultrasonic sensing technology to monitor the position of the front occupants, while also using a series of other sensors to detect the weight of the occupant, the driver's position relative to the steering wheel, whether the seat belt is fastened, and the strength of the collision when a collision occurs. Having mastered these detected information, ARTS can use its own inherent flexibility to determine the trigger time and deployment strength of the airbag according to the specific needs of each front row occupant, achieve the best occupant protection effect, and greatly reduce the Related injuries.
Development trend With the development of science and technology and people's increasing emphasis on vehicle safety, airbag technology in automotive safety technology has also developed rapidly in recent years. Intelligent, multi-airbags are the inevitable trend for the development of the overall airbag system in the future.
New technologies can better identify passenger types and take different protective measures. The system uses weight, infrared, ultrasonic and other sensors to determine the distance between the passengers and the instrument panel, weight, height and other factors, and then in the collision to determine whether to burst airbags, the use of a single ignition or multi-stage ignition, how much the point detonation force, and Seat belts form an overall control. Through the sensor, the airbag system can also determine the type of collision the vehicle is currently experiencing, whether it is a frontal collision or an angle collision, a side collision or a tumbling movement of the vehicle in order to drive the airbags in different positions of the vehicle body to form the best protection for the passengers.
The application of network technology is also the development direction of airbag systems. In the automotive network, there is a narrow, but very important network called Safe-By-Wire. Safe-By-Wire is a bus dedicated to automotive airbag systems. Safe-By-Wire technology aims to achieve a subtle control of the airbag system through the integrated use of multiple sensors and controllers. The Safe-By-Wire Plus bus standard was proposed by automotive electronics suppliers and component suppliers such as Philips and Delphi. The advantages of Safe-By-Wire compared to the bus systems such as CAN, FlexRay, etc., which are commonly used in vehicle systems, are that it is a car LAN interface standard specifically for airbag systems. In order to ensure that the system is not damaged in the event of an automobile accident, multiple protection functions are embedded in the Safe-By-Wire. For example, even if there is a short circuit in the line, the airbag system will not start due to an error. Safe-By-Wire technology will be widely used in automotive airbag systems.
Use of Airbags The driver should move the seat as far back as possible so that there is enough space for the airbag to fully exert its protection after accidental expansion. Drivers should not control the vehicle in a forward direction. They should sit correctly and close to the seatbacks and buckle up. Children under 12 should sit in the back of the car and buckle up. Young children weighing no more than 18 kilograms should be placed in the rear seats equipped with a child seat device and buckled.
Maintenance method There is an airbag indicator on the dashboard of the vehicle. Under normal conditions, the warning light will be on for about 4 or 5 seconds after ignition, self-tested, and then extinguished. If the warning light is always on, the airbag system is faulty and should be repaired immediately.
First you need to know that airbags are disposable products. After the airbags detonate in a collision, they no longer have protection capabilities, and each airbag can only be used once. The airbag is a one-time product and must be returned to the maintenance manufacturer to replace a new airbag after detonation. Because of different models, the price of airbags is not the same. The reinstallation of a new airbag, including the sensing system and the computer controller, will generally require around 5,000-10,000 yuan.
At the same time, you should also be careful not to place items in front of, above, or near the airbag. Since the airbag can be detonated in an emergency, do not place objects in front of, above or near the airbag to prevent it from being thrown out by the airbag during detonation, thus injuring the occupant. In addition, when installing accessories such as CDs, radios, etc. in the room, you must obey the manufacturer's regulations and do not arbitrarily modify the parts and lines that belong to the airbag system to avoid affecting the normal operation of the airbag; children should pay attention when using airbags. At present, many airbags are designed for adults, including the position and height of the airbag in the vehicle. When the airbag is inflated, it may cause injury to the front children. It is recommended that children be placed in the middle of the back row and fixed.
Pay attention to the daily maintenance of the airbag. The indicator light of the airbag is installed on the dashboard of the vehicle. Under normal circumstances, when the ignition switch is turned to the ACC position or the ON position, the warning light will light for about 45 seconds for self-test and then go out. If the warning light stays on, it indicates that the airbag system is faulty and should be repaired immediately to prevent the airbag from malfunctioning or popping out.
Classification According to the object of protection â— Front airbag: Driver Airbag (DA), Passenger Airbag (Passenger Front Airbag; PA)
Side airbags: Front Side Airbag (FSA), Rear Side Airbag (RSA)
â—Side Air Curtains â—Knee Airbags are divided by the number of single airbags and double airbags The number of airbags that are currently standard in mid- and low-end cars produced in China is 1-2, which are generally one in each of the driving and co-pilot positions of the vehicle. It is used to protect the front row members from effective protection of the chest and brain in the event of a violent impact on the vehicle.
Four airbags In some mid-range B-class cars, four airbags are generally installed in addition to two in the driving and front passenger seats, and two in its side door.
Multi-airbags are known for safety in some high-end cars. Sweden’s Volvo sedan is equipped with 6 airbags and 18 air curtains in its flagship model, which are located in the front and front passenger compartments of the vehicle, on both sides of the front and rear doors. Each of the two, 18 air curtains are located at the front and rear windshields and at the side windows, providing the most effective protection against impact from all directions.
Split air bag type safety belt according to innovation
The airbag-type seat belts that prevent automobile rebound and cause casualties are also called airbag-type seat belts. In the shoulder and the whole of the car belt, there is a peg-shaped airbag device. The belt combines the characteristics of conventional seat belts and airbags to provide passengers with a higher level of crash safety protection. This technology reduces injuries to the passenger's head, neck and chest during an accident. The use of airbag-type seat belts further enhances the vehicle's safety and innovation facilities, and it is a boon to children and the elderly.
This airbag type seat belt, when it comes to accidents, the seat belt will instantly expand into a balloon-like, its impact relief effect is 5 times that of the traditional seat belt; First, large area can effectively reduce the head and neck Shaking, and second, when the airbag inflates, it has a certain reaction force, which can reduce the phenomenon of rib fractures, internal organs damage and bruises that are likely to occur to passengers during accidents, and avoids the accidental injury of more than 60% of cervical vertebrae due to airbags.
The side airbag side airbag is mounted on the outside of the seat in order to mitigate the side impact. Nowadays, many manufacturers' models are equipped with standard side airbags for the front two seats, while the rear-mounted side airbags are rarely equipped.
Most knee airbags are equipped only with main and co-pilot airbags, side airbags, etc. In fact, when the vehicle actually encounters a frontal collision, the following is more protected. The distance between the lower knee and the center console is the shortest. It is the site most likely to cause fracture damage.
The knee airbag is used to reduce the occupant's knee injury to the interior of the vehicle in a secondary collision. The airbag in the knee part is located in the front driver's seat. Once it is opened, it can effectively protect the lower body parts of the rear passengers, which can also relieve the forward momentum from the frontal collision.
The head airbag head airbag is also called a side air curtain, which pops up and covers the windows in a collision to achieve the effect of protecting the passengers.
The head airbag is mainly used to protect the head of the occupant when a side collision occurs. The B-pillar side, window glass, and even seat belt side support buckles can all be killers in a car accident. Then the head airbag will separate the members from these things.
The head airbag is installed in the curved steel reed in the roof, usually through the front and rear, controlled by the lateral acceleration sensor in the body. The detonation is controlled when the lateral acceleration is greater than normal and reaches a dangerous value. It has good personnel protection functions for serious accidents such as side collisions and rollovers.
Working principle During the driving of the vehicle, the sensor system continuously sends speed change (or acceleration) information to the control device. The control device (central controller) analyzes and judges these information, if the measured acceleration, speed change, or other indicators exceed The predetermined value (that is, the actual collision), the control device sends a firing command to the gas generator generator or the sensor directly controls the ignition, an explosive reaction occurs after ignition, N2 is generated or the compressed nitrogen in the gas tank is released to fill the collision airbag . When the occupant comes into contact with the air bag, the impact energy is absorbed by the air vent hole of the air bag to protect the occupant.
The car's airbag contains substances such as sodium azide (NaN3) and ammonium nitrate (NH4NO3).
When a car is hit hard at high speeds, these substances will quickly decompose and produce a lot of gas, filling the airbags. [Sodium azide decomposes to produce nitrogen and solid sodium, ammonium nitrate is involved as an oxidant.
The new airbag incorporates a device that can inflate or release pressure in order to prevent the huge pressure generated by a sudden burst of fire from harming the human head, especially when the passenger does not wear a seat belt. The specific forms are:
1. The stage point explosion device, ie, the gas generator is divided into two stages, the first stage generates about 40% of the gas volume, far below the maximum pressure, which has a buffer effect on the movement of the human head, and the second stage of the point explosion generates residual gas. And reach the maximum pressure. In general, the maximum pressure of a two-stage burst is less than that of a single-stage burst. In this form, the pressure gradually increases.
2. The pressure relief mode is divided, and pressure holes or pressure-adjustable holes are opened in the pouch, which can be divided into two types, namely Tether, which is completely opened by means of gas pressure or a computer-controlled pull tab. In this way, the initial pressure reaches the set limit, and then the pressure is released instantaneously to avoid excessive damage.
Opening conditions In order to ensure that the airbag is opened at the appropriate time, the automobile manufacturer has specified the conditions for the initiation of the airbag. Only if these conditions are met, the airbag will explode. Although in some traffic accidents, the occupants of the vehicle have broken their heads, or even become life-threatening, and the vehicles are nearing end-of-life. However, if the condition of the airbag explosion is not reached, the airbags will not open.
Airbag opening requires proper speed and impact angle. In theory, only when the vehicle's position is about 60° from the front of the vehicle and it strikes a stationary object at a speed higher than 30km/h, the airbag can be opened. The speed mentioned here is not the vehicle speed that we understand in the ordinary sense, but the speed of the collision of fixed obstacles in the test chamber relative to the vehicle. The speed of the car in the actual collision is higher than the test speed.
The main parts of the car when the collision occurs are the bumper and the body longitudinal beam. In order to buffer the impact force during the collision, most of the front part of the car is designed with a collision buffer, and the rigidity distribution of the vehicle body is also uneven. In some accidents, such as when a rear-end rear-end collision occurred between a sedan and a truck without a rear guard, or a roll-over accident after a collision of a sedan, or a side collision with a vehicle, such accidents are often not directly hit by the front of the vehicle body. It is mainly the collision between the upper part and the side of the car body. The rigidity of the collision part is very small. Although the car cabin has undergone a great deformation, which has caused the injury or death of the occupants in the car, due to the wrong position of the collision, sometimes the air bag cannot be opened. Especially in side impacts, if no side airbags are deployed, the main and sub airbags cannot be detonated because they cannot reach the detonation conditions. Features Advantages Airbags can distribute impact forces evenly over the head and chest, preventing fragile passengers The direct collision of the body will greatly reduce the possibility of injury. Airbags can effectively protect passengers from frontal impact. Even without a seatbelt on a smart airbag, the airbag can still effectively reduce the damage. According to statistics, when a car with an airbag is hit in a frontal collision, the degree of passenger injury can be reduced by up to 64%, and even 80% of passengers are not wearing a seat belt! As for the collision from the side and the back seat, it still depends on the function of the seat belt. In addition, the airbag burst volume is only about 130 decibels, in the human body tolerable range; 78% of the gas in the airbag is nitrogen, very stable and non-toxic, harmless to the human body; the powder that is brought out to maintain the airbag Lubricated powders that do not stick together in the folded state are also harmless to the human body.
Defective airbags also have its unsafe side. According to calculations, if the car is traveling at a speed of 60 km/h, a sudden impact will cause the vehicle to stop within 0.2 seconds, and the air bag will pop up at a speed of about 300 km/h. The resulting impact force is about 180 kg. This is difficult for the vulnerable parts of the body such as the head and neck. Therefore, if the angle and intensity of the airbag pop up are slightly wrong, it is likely to create a "tragedy."
1. The airbag may open at very low speeds. When a car is driving at a low speed and a collision occurs, the occupant and the driver can fasten the seat belt, and no airbag protection is required at all. If the airbag is deployed at this time, it will cause unnecessary waste, and may even increase the crash damage due to deployment of the airbag.
2. Initiation of airbags can cause injuries to occupants. When the airbag system is activated, the airbag cover will be flushed and the inflation will be carried out in an instant, which may cause impact to the occupant; the hot gas generated may also burn the occupant and the driver.
3. When the passenger deviates from the seat or the seat is unoccupied or the child takes a ride, the activation of the airbag system not only fails to provide the necessary protection, but also may cause some damage to the occupant.
The improved technology can be seen from the defects in the use of airbags. The basic design objective of existing airbags is to deal with serious traffic accidents. However, in some less serious accidents, the system is overreacted, and it will Passengers exert excessive effects, which are counterproductive and cause unnecessary harm.
For practical problems, we also hope that before the airbag deployment, the airbag system can accurately detect the car's collision and determine the severity of the collision according to the program. If the collision level is relatively low, only safety The pretensioning mechanism of the belt can be tightened; if the collision level is relatively high and the airbag needs to be activated, the instruction to light the airbag is transmitted to the airbag system. This also means that the airbag system is required to accurately sense the collision accident; and it can imitate the human brain, determine whether the airbag needs to be deployed according to the actual collision degree, and has certain flexibility; and can appropriately target different occupants Adjust the airbag.
Magnetoelectric sensor sensor triggers are usually: switch type, purely mechanical type, single point electronic type, side impact type, strain type and so on. At present, there is no uniform standard for sensor triggering methods for airbags in automobiles. Not only is it a wide variety of types, but also because the sensor triggering methods installed on different positions on the vehicle body are also different. In order to enable the sensor to be conveniently installed in each required sensing area, so that it can accurately and timely sense the collision, a magnetoelectric sensor can be selected.
The magnetoelectric sensor can be installed anywhere on the vehicle body, as long as some parameter values ​​are slightly adjusted, making it possible to identify collision acceleration signals with a peak value of 0588 m/s and a time pulse of 0-20 ms. As long as the collision acceleration peak and time pulse width meet the conditions at the same time, it will send a trigger signal to the airbag to deploy the airbag to protect the human body.
The sensor structure consists of a housing (non-magnetic material), magnetic material, inertial body (non-magnetic material), soft iron attached to the inertial body, a spring for supporting and adjusting the displacement amplitude, and a permanent installed in the flange connected to the housing. Magnets and coils and leads wound on soft iron. When the sensor is subjected to a collision acceleration, the inertial body generates a reverse acceleration, which results in a change in the magnetic flux passing through the coil. A bell-shaped pulse signal is generated at both ends of the coil lead. When the spring stiffness is adjusted, the width of the acceleration signal may be changed.
The signal discriminating circuit of the sensor is composed of three parts: signal amplitude discriminating circuit; signal width discriminating circuit; useful and useless signal discriminating circuit. By multi-directionally judging the collision signal, the collision signal obtained by the control device can be more comprehensive and the ignition control issued can be more accurate, thereby ensuring that the airbag is deployed under necessary conditions.
How to obtain a stable impact acceleration signal is research; the key of the sensor is also the key to ensure the sensor accurately obtains the collision signal. The magnetoelectric acceleration sensor adopts a drop-weight impact test device to adjust and correct its sensitivity to induction. When the hammerhead is released and collided with the rubber surface, the acceleration or magnetoelectric sensor mounted on the hammerhead will feel the impact acceleration. Different drop heights correspond to different accelerations; adjusting the rubber thickness can change the signal width; adjusting the drop hammer height can change the signal amplitude.
Magnetoelectric sensors not only have low error rate in the electronic identification circuit, but also have high reliability and accuracy in the induction collision signal. Moreover, the width of the sensing range can be adjusted by the calibration of the hammer to meet the recurrence of the impulse generated by the car collision, and thus can also be installed. On any part of the body. There is also its simple design, low price, and it is no longer a prohibitive luxury for most car users.
The requirement of the intelligent control system for the airbag control system is to accurately determine the crash intensity of the accident and control the deployment of the airbag. For the defects in the use of airbags, we must further improve the flexibility and accuracy of the control system. For this reason, we can adopt an intelligent control system.
1. Collision sensor. The function of the important components in the airbag system is to detect and determine the impact signal of the car after the collision in order to decide whether to open the buffer airbag. Collision sensors mainly use three types of mechanical sensors used in early airbags. The main application of inertial principle is to use the inertia force of the components in the sensor to overcome the spring force to trigger the gas generator. The mechanical type ensures that the airbag is not activated when the acceleration is low, and the reliability is high; however, only a single point of sensing is available, and the requirements for the quality, precision, and wear resistance of the mechanical parts are extremely high.
The electronic sensor is one of the earliest collision sensors used. According to the electronic principle, the electric signal is used to reflect the deceleration of the vehicle, and then it is determined based on the electric signal whether to open the buffer airbag.
Electromechanical sensors use electromechanical methods to convert mechanical signals into electronic signals and then use electronic signals to burst airbags. That is to say, it has the advantages of mechanical, but also can overcome the defects of the mechanical sensor itself, installed in any position on the body in order to get a better deceleration signal, and can install multiple sensors in the same position.
2. Buffer airbags. The airbag is generally made of polyamide fabric with good anti-cracking performance. It is a semi-rigid foam plastic that can withstand greater pressure. After vulcanization treatment, it can reduce the inertia force when the airbag is inflated; Sealed, airbag coated with coating material. The size, shape, and air leakage performance of the airbag are important factors in determining the airbag protection effect and must be determined according to the actual conditions of different automobiles.
At present, airbag system developers are developing intelligent airbag systems based on neural network principles. It mainly uses nerve endings (ie, various sensors) to transmit various information of the surrounding environment it explores to the central nervous system (ie, computer or computer), and can collide the collision type of the accident, the severity of the collision accident, and the time of collision. The information such as the speed of the vehicle is transmitted to the computer, and the computer processes and analyzes the information, responds accordingly, and executes the correct airbag protection program corresponding to the information, which is the so-called intelligent control system.
The intelligent control system generally consists of two parts, a software part and a hardware part. The hardware part mainly consists of the electronic control unit (including the SCM, sensors, ignition circuit, etc.) and the ground part (including the serial communication circuit, computer system, etc.) of the vehicle-mounted part; the software part is mainly composed of the single-chip microcomputer, the computer part and the microcomputer part. Control system block diagram shown in Figure 2. Injury to airbags, poor protection or waste.
The occupant detection system is aimed at the airbags failing to provide appropriate protection for different occupants. We can install an occupant detection system on the occupant's seat to detect whether there are people on the seat, the size of the occupants, and the deviation from the middle when seated. . Equivalent to a sensor installed specifically to detect passengers ride information and pass it to the central computer control center. If a collision occurs, the control center makes a comprehensive assessment of the occupant's ride information detected by the occupant detection system while judging the information transmitted from various sensors. In this case, the airbag system can deploy the airbags in proper and timely manner for the driver and the occupant, completely avoiding the need for an ideal airbag to protect the user of the vehicle against various special conditions. Airbags should collect and use as much data as possible about the occupant's position information, the type of crash and the speed of crashes, establish a database, identify and judge information about the occupants and cars in the collision, and adjust the safety restraint system parameters so that the human body can obtain the most Good protection. To achieve this ideal, take our current research. In fact, there may be a long gap, but we can complete it step by step. The above discussion and reflection is only a step toward the ideal. It is believed that with the development of science and technology research, our vehicle safety measures will be more perfect.
The diversification of gas generators for gas generators requires not only reliable operation, stable performance, good durability, and compliance with environmental requirements, but also requires minimizing their quality and reducing costs. Especially in the case of airbag gas injury, it is even more demanding to improve the gas generator. At present, airbag systems on automobiles employ a large number of propellant-type gas generators using azide as a gas generating material, and other types of gas generators include a mixed gas type gas generator, a liquid (liquid gas) type gas generator, and compressed air. Energy storage gas generators and nitrocellulose gas generators are also actively researched and developed. For example, a low-density, non-toxic gas-type gas generator produced by Molton Company has the advantages of small size and light weight compared with existing ones; a new type of sodium-free azide gas developed by Brad Company has occurred. The device consumes less than 40% of the sodium azide gas generating agent and can produce an equal amount of gas, thereby reducing its volume and quality.
It is to add sensors on the basis of the general type to detect whether the occupants of the seat are children or adults. How fast the seat belts and the position of the occupants are, and by collecting these data, it is analyzed by the computer software. And deal with controlling the inflation of the airbag so that it can play its best role and avoid unnecessary expansion of the airbag, thereby greatly improving its safety. Smart airbags have two more core components than the common ones, namely sensors and their associated computer software.
History of development The idea of ​​using airbags to protect car occupants was first generated in the United States. In 1952, the American Automobile Manufacturers Association theoretically elaborated on the necessity of such a car safety system. Almost at the same time, the schematic diagram of such a system was also drawn up. In August 1953, Hurtrik first proposed the "airbag protection device for automobiles" and obtained the patent for "car buffer safety device" in the United States. However, because of the technical level at the time, this idea or patent could not be implemented. In 1966, Mercedes-Benz began developing airbag devices. Mercedes engineers first invented crash sensors and gas generating devices to allow airbags to inflate in 30 milliseconds. They also developed tear-resistant airbag fabrics. Improve the airbag's expansion characteristics, and finally, the entire device design is installed in the car's steering wheel. After about 250 real-vehicle crash tests, 2,500 bench trials, and over 7 million km of vehicle road tests, in December 1980, along with pre-tensioned seat belts, airbags were installed at the time. Mercedes-Benz S-Class sedan. Since 1985, Mercedes-Benz has installed this safety system on all vehicles that supply the US market. In 1991, almost 28% of Mercedes-Benz cars were equipped with driver airbags. It has been 25 years since the Mercedes-Benz S-Class, which was the earliest to have airbags, drove off the production line. According to statistics of the National Highway Safety Administration (NHTSA) of the United States, airbags have protected about 14,200 lives in accidents in the United States. In Germany, airbags have blocked 2 500 since 1990. Examples of traffic accidents that have caused major injuries. According to statistics, airbags can protect about one-third of the personnel from surviving in a serious collision accident. In addition, one-sixth of drivers or front passengers can be rescued by airbags during a collision. The use of airbags significantly improves the passive safety of the car.
At present, many countries in the world require airbags to be installed on new cars. For example, in the United States, the corresponding regulations have been implemented since 1989. This regulation not only requires that all new vehicles must be equipped with airbags, but also that the size of the airbags be regulated. Americans think that the bigger the airbag is, the better, while European experts believe that the best solution should be the use of seatbelts and small-sized airbags. Therefore, European companies only produce small-sized airbags. Nowadays, a common arrangement in a car is that one airbag is mounted on the steering wheel, and the other is installed in front of the front passenger next to the driver. Modern airbags are made of nylon and the inner surface is coated with a layer of synthetic rubber or Silicone Rubber to ensure hermeticity. The inner surface of the airbag is fixed with special straps which keep it in shape when the airbag is inflated. The side of the airbag is provided with a plurality of holes which are used to rapidly discharge gas from the airbag to facilitate the cushioning of the impact. In order to avoid the air bags from being stacked for a long time to form a hard block, a special material is covered inside the air bag, which can make the effective service period of the air bag reach 15 years.
As the earliest manufacturer of airbags, Mercedes-Benz has so far equipped its airbags with 12 million vehicles. In 1992, airbags were already a standard configuration for Mercedes-Benz cars. In recent years, Mercedes' engineers are still working on technologies for improving airbags, including side airbag systems and airbag control systems that can respond better in an accident.
The use of airbags significantly improves the passive safety of the car. According to statistics, due to the widespread use of airbags in North America, the accidental death rate has decreased by 12%, and the degree of injury to the human body has also been reduced under the protection of airbags. However, the automotive airbag system also has an astonishingly damaging negative effect, of which the most important one is twofold. On the one hand, the traditional frontal collision airbag system is designed based on the conventional seating position and posture of the front seat occupant and the ideal ignition timing of the airbag. However, in the actual automobile collision accident, there are many factors that affect the protection effect of the airbag, such as the occupant. The height and weight, the position of the occupant relative to the steering wheel or dashboard, the severity of the collision, etc., different collision conditions and changes in the position of the occupant will result in the occupant not being in contact with the airbag at the optimum moment. This reduces the protective effect on the occupants and sometimes hurts the life of the occupants.
On the other hand, although the quality of airbags made of nylon or polyester fabrics is not large, the instantaneous deployment speed is as high as 200km/h or more. This impact speed is not a small number for the human body, according to the US National Highway. According to the statistics of the safety management department, while airbags saved 100 lives during a collision accident, unfortunately, 57 occupants lost their lives due to improper deployment of airbags and improper seating and sitting positions of occupants. In the next few years, airbags will still play an important role in car safety equipment. The possibility that engineers are looking for an active safety system that can automatically adjust to possible accidents and car drivers, the development of new intelligent airbags puts higher requirements on new technologies. Due to the way the airbag is used, the impact caused by the blasting force has some harm to the human body. When the distance between the driver and the steering wheel airbag liner is less than 10cm, the airbag exploded in 20-30ms will give the driver a fatal impact injury. However, if the members of the front passenger seat do not maintain a proper sitting posture, the possibility of causing injuries in the collision will also greatly increase.
At present, there are two trends in the development of airbags. Automobile companies in the United States and Japan are trying to increase the size of airbags to protect occupants. And some European automobile manufacturing companies, such as Mercedes-Benz, BMW and Volvo, believe that the airbag itself is by no means a guarantee for the occupant's panacea. It must be effective in a unified passive safety system for cars. In this system, certain Should be equipped with a constricted seat belt, a seat with a reliable structure, a seat for children and a series of other components. Moreover, it is best to consider the installation of all necessary components of the safety system at the beginning of the design of the body structure.
Now, in Mercedes-Benz's PRE-SAFE pre-warning safety system, the airbag, as its main part, is controlled by an early warning sensor. The airbag can be deployed before the collision begins and it can better cushion the collision energy during the collision. The PRE-SAFE pre-alarm safety system further enhances the protection effect of the seat belt and the airbag. The warning device can judge the impending accident and adjust the seat and pretension the seat belt when there is a possibility of collision. , so that the passengers in the car get the best protection in the collision, even in the moment of collision early detonation of airbags, so that the impact of the buffer capacity to achieve the best.
The intelligent development of airbags in the future also includes the integration of advanced sensor technologies and information processing systems, which can provide reliable information on collision environment during the short time of an accident. This information includes the severity of the car crash, the form of the collision (positive or side-impact, etc.), the occupant's size, weight, seating position and riding posture, and whether the occupant is wearing a seat belt. Based on the detected information, the intelligent airbag system calculates and analyzes the electronic control system to determine when and how much the airbag deploys, thus providing the occupant with optimal protection.
Both Siemens of Germany and Jaguar of the United Kingdom have developed a management system that can control the detonation of air bags based on collision environment information. Siemens uses three-dimensional cameras and weight sensors in seats to identify the position and sitting position of occupants sitting in each seat in the vehicle, while Jaguar uses the Adaptive Constraint Technology System (ARTS) on each of its xK series models. The system uses ultrasonic sensing technology to monitor the position of the front occupants, while also using a series of other sensors to detect the weight of the occupant, the driver's position relative to the steering wheel, whether the seat belt is fastened, and the strength of the collision when a collision occurs. Having mastered these detected information, ARTS can use its own inherent flexibility to determine the trigger time and deployment strength of the airbag according to the specific needs of each front row occupant, achieve the best occupant protection effect, and greatly reduce the Related injuries.
Development trend With the development of science and technology and people's increasing emphasis on vehicle safety, airbag technology in automotive safety technology has also developed rapidly in recent years. Intelligent, multi-airbags are the inevitable trend for the development of the overall airbag system in the future.
New technologies can better identify passenger types and take different protective measures. The system uses weight, infrared, ultrasonic and other sensors to determine the distance between the passengers and the instrument panel, weight, height and other factors, and then in the collision to determine whether to burst airbags, the use of a single ignition or multi-stage ignition, how much the point detonation force, and Seat belts form an overall control. Through the sensor, the airbag system can also determine the type of collision the vehicle is currently experiencing, whether it is a frontal collision or an angle collision, a side collision or a tumbling movement of the vehicle in order to drive the airbags in different positions of the vehicle body to form the best protection for the passengers.
The application of network technology is also the development direction of airbag systems. In the automotive network, there is a narrow, but very important network called Safe-By-Wire. Safe-By-Wire is a bus dedicated to automotive airbag systems. Safe-By-Wire technology aims to achieve a subtle control of the airbag system through the integrated use of multiple sensors and controllers. The Safe-By-Wire Plus bus standard was proposed by automotive electronics suppliers and component suppliers such as Philips and Delphi. The advantages of Safe-By-Wire compared to the bus systems such as CAN, FlexRay, etc., which are commonly used in vehicle systems, are that it is a car LAN interface standard specifically for airbag systems. In order to ensure that the system is not damaged in the event of an automobile accident, multiple protection functions are embedded in the Safe-By-Wire. For example, even if there is a short circuit in the line, the airbag system will not start due to an error. Safe-By-Wire technology will be widely used in automotive airbag systems.
Use of Airbags The driver should move the seat as far back as possible so that there is enough space for the airbag to fully exert its protection after accidental expansion. Drivers should not control the vehicle in a forward direction. They should sit correctly and close to the seatbacks and buckle up. Children under 12 should sit in the back of the car and buckle up. Young children weighing no more than 18 kilograms should be placed in the rear seats equipped with a child seat device and buckled.
Maintenance method There is an airbag indicator on the dashboard of the vehicle. Under normal conditions, the warning light will be on for about 4 or 5 seconds after ignition, self-tested, and then extinguished. If the warning light is always on, the airbag system is faulty and should be repaired immediately.
First you need to know that airbags are disposable products. After the airbags detonate in a collision, they no longer have protection capabilities, and each airbag can only be used once. The airbag is a one-time product and must be returned to the maintenance manufacturer to replace a new airbag after detonation. Because of different models, the price of airbags is not the same. The reinstallation of a new airbag, including the sensing system and the computer controller, will generally require around 5,000-10,000 yuan.
At the same time, you should also be careful not to place items in front of, above, or near the airbag. Since the airbag can be detonated in an emergency, do not place objects in front of, above or near the airbag to prevent it from being thrown out by the airbag during detonation, thus injuring the occupant. In addition, when installing accessories such as CDs, radios, etc. in the room, you must obey the manufacturer's regulations and do not arbitrarily modify the parts and lines that belong to the airbag system to avoid affecting the normal operation of the airbag; children should pay attention when using airbags. At present, many airbags are designed for adults, including the position and height of the airbag in the vehicle. When the airbag is inflated, it may cause injury to the front children. It is recommended that children be placed in the middle of the back row and fixed.
Pay attention to the daily maintenance of the airbag. The indicator light of the airbag is installed on the dashboard of the vehicle. Under normal circumstances, when the ignition switch is turned to the ACC position or the ON position, the warning light will light for about 45 seconds for self-test and then go out. If the warning light stays on, it indicates that the airbag system is faulty and should be repaired immediately to prevent the airbag from malfunctioning or popping out.
Fast Cure Sealant,Sealant for General Purpose,OEM Sealant
Neutral Silicone Sealant,Professional Silicone Adhesive Co., Ltd. , http://www.chsiliconesealant.com