In the past, consumers used to regard ABS as an important indicator when buying a car. With the development of technology, at present, most domestic cars adopt ABS as the standard configuration. However, many drivers are not very clear about the understanding and correct use of ABS, and even have some misunderstandings about ABS. Some drivers think that ABS is a device to shorten the braking distance. The braking distance of vehicles equipped with ABS on any road surface must be shorter than that of vehicles without ABS. Some people even mistakenly think that the braking distance on ice and snow pavement can be equivalent to that on asphalt pavement. There are also some drivers who believe that as long as ABS is equipped, even if driving at high speed on rainy days or icy roads, there will be no loss of control of vehicles. ? ABS has not greatly improved the limit of automobile physical properties as some people think. Strictly speaking, the function of ABS is mainly to ensure the maneuverability and stability of the vehicle itself when braking within the physical limit performance.
Application of ABS
The full name of ABS is anti-lock braking? Brake? System (anti-lock braking system) or anti-skid? Brake? The system (anti-skid braking system) can effectively control the wheels to keep in a rotating state, improve the stability of automobile braking and the braking performance of automobile in bad road conditions. ABS constantly detects the rotational speed of each wheel through the rotational speed sensor installed on each wheel or transmission shaft, and the computer calculates the wheel slip rate at that time and compares it with the ideal slip rate, so as to make a decision to increase or decrease the braking pressure of the brake, and order the actuator to adjust the braking pressure in time to keep the wheel in an ideal braking state.
1906 ABS obtained the patent for the first time, and1936abosch registered the "mechanical" patent to prevent the wheels of motor vehicles from locking. All early designs have the same problem: too complicated, easy to fail and too slow to operate. 1947 the world's first ABS system was first applied to the B-47 bomber. Teldix company began to study this project on 1964, and its ABS research was quickly taken over by Bosch. Within two years, the first batch of ABS test vehicles have the function of shortening the braking distance. When turning, the steering and stability of the vehicle were also ensured, but at that time, analog components and safety switches of about 1000 were used, which means ABS? 1 The reliability and durability of the electronic control unit of the system can't meet the requirements of mass production and need to be improved. Bosch's technology in developing electronic engine management, digital technology and the arrival of integrated circuits (ICs) have reduced the number of electronic components to 140.
1968 ABS began to study and apply to automobiles. 1975 due to the adoption of the American federal motor vehicle safety standard 12 1, many heavy trucks and buses are equipped with ABS. However, due to many technical problems in the braking system and the opposition of the truck industry, the standard was revoked in 1978. In the same year, Bosch, as the first company in the world to launch an ABS system with electronic control function, put this ABS? The 2 system was installed as an optional configuration, assembled on Mercedes-Benz S-Class cars, and soon installed on BMW 7 Series luxury cars. After this period, the further research and design of ABS in the United States decreased, but manufacturers in Europe and Japan continued to carefully develop ABS.
Since 1980s, American automobile manufacturers have shown new interest in ABS in American automobile market, because all cars imported from America are equipped with ABS. With the rapid development of microelectronics technology and people's strong demand for automobile driving safety, ABS devices have been further widely used in the world automobile industry. 1987, about 3% cars in the United States were equipped with very reliable ABS. In the following time, developers focus on simplifying the system. In 1989, Bosch engineers successfully installed the hybrid control unit directly on the hydraulic module. So they don't need to connect the wiring harness between the control unit and the hydraulic module, and they don't need connectors. So ABS? 2E Total weight.
In 1993, Bosch engineers created ABS with a new electromagnetic valve. 5.0, and 5.3 was developed in the following years? And 5.7? Version. The main features of the new generation ABS are reducing the weight, reducing the volume, increasing the memory, and adding more functions, such as electronic distribution of braking pressure, thus replacing the mechanical mechanism to reduce the braking pressure of the rear axle. At that time, the predictions of some auto industry analysts were confirmed: after the mid-1990s, most cars and trucks in the world market will be equipped with ABS.
Edit the function of ABS in this paragraph.
The main function of ABS is to improve the braking performance of the whole vehicle, improve the driving safety, prevent the wheels from locking when braking (that is, stop rolling), ensure that the driver can still control the direction when braking, and prevent the rear axle from slipping. Its working principle is: in the case of emergency braking, once the wheel is found to be locked, the computer immediately controls the pressure regulator to release the pressure of the wheel brake cylinder, so that the wheel can resume rotation and achieve the purpose of preventing the wheel from being locked. The working process of ABS is actually a cyclic working process of "locking-releasing-locking-releasing", which keeps the vehicle rolling in the critical locking gap all the time, effectively overcomes the vehicle deviation caused by wheel locking during emergency braking, and prevents the occurrence of out-of-control situations. ?
ABS can be divided into mechanical type and electronic type. Mechanical ABS has a simple structure, and the braking force can be simply adjusted mainly by using its own internal structure. The working principle of the device is simple, there is no sensor to feed back signals such as road friction and wheel speed, and it works entirely by preset data. Whether it is a waterlogged pavement, an icy pavement, a muddy pavement or a good cement asphalt pavement, its working mode is the same. Technically, this ABS can only be called? "Advanced braking system (advanced? Brake? At present, only some low-end pickup trucks and other models in China still use mechanical ABS.
Mechanical ABS only uses the physical characteristics of components for mechanical movement, while electronic ABS uses computers to analyze and calculate various data to get results. Electronic ABS consists of wheel speed sensor, wire harness, computer, ABS hydraulic pump, indicator light and other components. According to the signal of the wheel speed sensor of each wheel, the computer can apply different braking force to each wheel, so as to achieve the effect of scientific and reasonable distribution of braking force.
The earliest ABS system was a two-wheel system. The so-called two-wheel system is to install ABS on the two rear wheels of the car. Because the two rear wheels share a brake hydraulic pipeline and a control valve, it is also called "single channel control system". This system selects the braking pressure according to the state of the wheel with less adhesion among the two rear wheels, which is the so-called "low selection principle". That is to say, when one rear wheel of ABS vehicle adopts the principle of low selection and tends to lock, the system can only release pressure to both rear wheels at the same time. Because the front wheel has no anti-lock function, it is difficult for the two-wheel system to achieve the best braking effect.
With the development of related technology, a "three-channel control system" appeared later. Based on the two-wheel system, the two front wheels are independently controlled by two independent pipelines. Although the rear wheel still adopts the principle of "low selection", this system has the main characteristics of modern ABS because it realizes the steering function during emergency braking and the function of preventing the rear axle from slipping. Up to now, there are still vehicles in the market using this three-channel control ABS system.
At present, the most common vehicles are equipped with four sensors and four channels of ABS system, and each wheel is controlled by an independent hydraulic pipeline and solenoid valve, so that the independent control of a single wheel can be realized. This structure can achieve good anti-lock function.
Edit this paragraph to get out of the misunderstanding of ABS
The misunderstandings about ABS at the beginning need to be explained. If the wheels lock when the car brakes, the lateral adhesion that the car can get is the smallest. At this time, due to the imbalance of road adhesion coefficient, automobile braking force, suspension imbalance, automobile tire pressure, road curvature, bump or slope, the automobile may slip, tail flick or get out of control. In addition, because the front wheel of the vehicle is locked, the car will lose its steering ability. An anti-lock braking system with excellent performance can control the slip rate of automobile wheels between 20% and 30% when braking. In this state, the wheels can give consideration to the relative maximum longitudinal braking force and lateral grip, effectively ensuring that the vehicle will not get out of control. In addition, under the condition that the front wheel is not locked, the car can turn according to the driver's wishes because of its certain grip, thus controlling the vehicle. In order to control the wheel slip rate in an ideal state and pursue the stability of the vehicle, some longitudinal braking force may be sacrificed. Therefore, when ABS works, the braking distance will not be shortened on all roads.
On ice and snow roads, the adhesion provided by the ground is much smaller than that provided by ordinary roads. ABS can only adjust the braking force of the car on the basis of this adhesion, and will not produce additional braking factors. Therefore, the braking distance on the ice and snow road can only be said to be shorter than that when the wheel is held, and it is still much longer than that on the general road.
In fact, the actual road is very complicated, such as the unbalanced adhesion coefficient of the road surface, the curvature of the road surface or the cross slope of the road surface, and even the tire pressure of the car. There are many factors that can make the car slip when braking, and these factors cannot be overcome by ABS itself. Therefore, if the vehicle brakes suddenly when the speed is too fast on the ice and snow road, when one of the above factors is encountered, when the centrifugal force of the vehicle is greater than the maximum lateral force provided by the ground, the vehicle will become out of control, which is very dangerous.
In short, no equipment is omnipotent, and drivers must achieve safe driving through their own subjective initiative. Even the ABS with excellent performance has limited effect on the stability of vehicles under working conditions, especially when driving on gravel roads or ice and snow roads, it is necessary to keep enough distance between vehicles, slow down and do not rely entirely on ABS system.
Edit this paragraph of ABS common sense.
Now basically all passenger cars are equipped with ABS system, which plays a great role in improving the active safety performance of vehicles, but if it is used improperly, the effect will be greatly reduced. Here, we summarize the principle of using ABS as "four musts and seven don 'ts".
Four elements
1. Always keep pressing the brake pedal to ensure sufficient and continuous braking force and make ABS work effectively.
2. Keep enough safe distance. In general, the minimum distance between cars should not be less than 50m. When the vehicle speed exceeds 50km/h, the minimum distance is the same as the vehicle speed. For example, the minimum vehicle distance is 100 m when 100 km/h and 120 m when 120 km/h. ..
3. Be familiar with ABS in advance, so that you can get ready to adapt to the brake pedal jitter when ABS works.
4. Read the driver's manual in advance to learn more about the various operating instructions provided by the automobile manufacturer that installed ABS. ?
Seven don't.
1. Don't think that you can drive at will with ABS. ABS is not absolutely safe. If the vehicle brakes too hard and too fast, it will still slip. Therefore, even if your car is equipped with ABS, you still need to drive carefully.
2. Don't use the "point brake" brake. When vehicles without ABS are braking on wet roads and at high speed, it is necessary to use the method of "point braking" to achieve the purpose of safe braking. After the installation of ABS, because ABS can automatically adjust the braking force, when implementing emergency braking, you can step on the pedal to the bottom without releasing it, so you don't have to worry about the wheel locking and slipping, otherwise the braking distance will be greatly extended.
Don't be scared by the jitter of ABS. When ABS works, it will hear the noise, which is generated by the solenoid valve and hydraulic pump in the hydraulic control system. Don't panic because there is something wrong with the brake system, and don't take your feet off the brake pedal. At this time, you still have to trample the brake pedal to death, regardless of it.
4. Don't ignore the inspection of ABS indicator light. Under normal circumstances, after the ignition switch is turned on, this light should be on; It goes out automatically after about 3 seconds. In this process, in essence, the electronic control device checks the wheel sensor and the control valve of the hydraulic regulator according to the self-checking procedure. If this light doesn't light up all the time, it means there is something wrong with ABS.
Don't panic at 5.5. ABS indicator does not go out. When the ABS breaks down during driving, the anti-lock braking system will automatically connect the oil circuit of the original braking system, and the original braking system on the car still works, but there is no ABS, so it is enough to pay attention to maintenance.
6. Do not change the computer unit of ABS without permission. If the computer finds a fault, the whole ABS unit should be replaced.
7. For the vehicle equipped with ABS, but want to modify it, please do not remove the nut connecting the brake pipe and ABS unit.
ABS is divided into electronic ABS and mechanical ABS.
1, electronic ABS is designed according to different models, and its installation requires professional technical force. If you switch to another car, you must change the circuit design and battery capacity, which is not universal; Mechanical ABS is multifunctional, can be used in any vehicle with hydraulic braking device, and can be changed from one vehicle to another, and the installation only takes 30 minutes. ?
2. Electronic ABS is bulky, so the finished car may not have enough space to install electronic ABS. In contrast, mechanical ABS is small in size and takes up less space.
3. The electronic ABS starts to work at the moment when the wheel is locked, and it works 6~ 12 times per second; Mechanical ABS starts to work when braking, and can move 60~ 120 times per second according to different vehicle speeds.
The applicable characteristics of mechanical ABS need to be set in advance. On the pavement with water, ice and snow, gravel and asphalt, the friction coefficient of tires is different, and the braking force required at different speeds is also different. There is no real-time measurement feedback system and only depends on the preset terbium value, so the application range is narrow and the braking effect will be reduced. ?
You should be very careful when buying mechanical ABS anti-lock braking system. Fake ABS products are similar in appearance and structure, but inferior products are difficult to withstand the corrosion and high pressure of brake oil for a long time, and rubber will age and deform with time and lose its due performance.
The genuine rubber valve capsule can withstand high pressure per square inch 1 1000 pounds when immersed in brake oil, and will not deform for a long time. The price of imported mechanical ABS is about 2000 yuan, and domestic ABS is only 200 yuan.
Edit ABS function in this paragraph.
c？
Function name:? abs？
Work? Can: Find the absolute value of an integer?
Use? Law:? int？ abs(int？ I)； ?
Program example:?
# Contains? & ltstdio.h & gt？
# Contains? & ltmath.h & gt？
int？ main(void)？
{?
int？ Number? =? - 1234; ?
Printf ("No.:? %d？ Absolutely? Value:? %d\n ",number,? Abs (digital)); ?
Return? 0; ?
}?
Pascal?
Function? Abs(？ x？ :? Real? )? :? Desire;
Work? Can: Find the absolute value of a number?
Example:?
begin
{? Statement; ? {? (? X data type? )? Output results? }? }
Writeln(？ Abs(84.23)？ ); ? {(true)? 8.42300000000000E+000 1？ }
Writeln(？ ABS(- 1 1 1222333)？ ); ? {(longing)? 1 1 1222333? }
Writeln(？ ABS(- 1 1 12223334324445556)？ ); ? {(Int64)？ 1 1 12223334324445556? }
End.
Edit this ABS plastic
Abs plastics
Chemical name: acrylonitrile-butadiene-styrene polymer?
English name: acrylonitrile? Butadiene? Styrene (ABS)
Uses: automobile parts (dashboard, tool door, wheel cover, mirror box, etc. ), radio case, telephone handle, high-strength tools (vacuum cleaner, hair dryer, blender, lawn mower, etc. ), typewriter keyboards, recreational vehicles such as golf carts and jet skis.
Specific gravity: 1.05g/cm3?
Identification method of combustion: continuous combustion, yellow flame on blue background, black smoke and faint marigold flavor.
Solvent experiment: Cyclohexanone can soften, but aromatic solvents have no effect.
Drying conditions: 80-90℃? 2 hours
Molding shrinkage: 0.4-0.7%?
Mold temperature: 25-70℃ (mold temperature will affect the finish of plastic parts, and the lower the temperature, the lower the finish).
Melting temperature: 2 10-280℃ (suggested temperature: 245℃)
Molding temperature: 200-240℃?
Injection speed: medium and high speed
Injection pressure: 500- 1000 bar
Features:?
1, good comprehensive performance, high impact strength, good chemical stability and electrical properties.
2. It has good weldability with 372 plexiglass, can be made into two-color plastic parts, and the surface can be chrome-plated and painted.
3, high impact resistance, high heat resistance, flame retardant, reinforced and transparent. ?
4. the fluidity is a little worse than HIPS, better than PMMA and PC, and the flexibility is good. ?
Uses: Suitable for manufacturing general mechanical parts, wear-resistant parts, transmission parts and telecommunication parts.
6. Like PVC (polyvinyl chloride), there will be whitening at the bend.
Molding characteristics:?
1. Amorphous materials with medium fluidity and high hygroscopicity must be fully dried. Plastic parts with glossy surface should be preheated and dried at 80-90 degrees for 3 hours.
2. It is advisable to adopt high feed temperature and high mold temperature, but it is easy to decompose when the feed temperature is too high (decomposition temperature > 270 degrees). For high-precision plastic parts, the mold temperature should be 50-60 degrees, and for high-gloss heat-resistant plastic parts, the mold temperature should be 60-80 degrees.
3. In order to solve the problem of water inclusion, it is necessary to improve the fluidity of materials and adopt methods such as high feed temperature, high mold temperature or changing water level. ?
4. If heat-resistant or flame-retardant materials are formed, after 3-7 days of production, plastic decomposition products will remain on the surface of the mold, resulting in the surface of the mold shining. The mold needs to be cleaned in time, and the exhaust position on the mold surface needs to be increased. ?
ABS resin is the largest and most widely used polymer at present. It organically unifies various properties of PS, SAN and BS, and has excellent mechanical properties of toughness, hardness and rigidity in balance. ABS is a terpolymer of acrylonitrile, butadiene and styrene, where A stands for acrylonitrile, B stands for butadiene and S stands for styrene. ?
ABS engineering plastics are generally opaque, light ivory in appearance, non-toxic, tasteless, tough, hard and rigid, burning slowly, with yellow flames and black smoke. After burning, the plastic softens and burns, giving off a special cinnamon smell, but there is no melting and dripping phenomenon. ?
ABS engineering plastics have excellent comprehensive properties, such as excellent impact strength, good dimensional stability, electrical properties, wear resistance, chemical resistance, dyeability, good moldability and so on. ABS resin is resistant to water, inorganic salts, alkali and acid, insoluble in most alcohols and hydrocarbon solvents, but soluble in aldehydes, ketones, esters and some chlorinated hydrocarbons. ?
Disadvantages of ABS engineering plastics: low thermal deformation temperature, flammability and poor weather resistance.
ABS Classification Society Certification Icon
ABS: short for American Bureau of Shipping.
Edit asset-backed securities in this section.
ABS？ Asset-backed securities (also called asset-backed securities or asset-backed securities, English: asset-backed? Securities) bonds or bills issued by banks, credit card companies or other credit providers according to loan agreements or accounts receivable; It is different from mortgage.
ABS is a securitization financing method supported by non-residential mortgage assets, which is actually the promotion and emergence of MBS technology in other assets. Because a basic condition of securitization financing is that the basic assets can generate predictable and stable cash flow, there are many assets with this characteristic besides housing mortgage loans, so they can also be securitized. With the continuous development of securitization technology and the continuous expansion of securitization market, ABS is becoming more and more diversified, which can be subdivided into the following categories: (1) securitization of automobile consumption loans and student loans; (2) Commercial, agricultural and medical real estate mortgage securitization; (3) securitization of credit card accounts receivable; (4) Securitization of trade receivables; (4) Securitization of equipment rental fees; (5) Securitization of infrastructure charges; (6) Securitization of ticket revenue; (7) Securitization of club membership fee income; (8) Securitization of premium income; (9) SME loan securitization; (10) Intellectual property securitization and so on. Moreover, with the continuous development of asset securitization technology, the scope of securitization assets is also expanding.
I hope I can help you, this should be very comprehensive, remember to add points!