I think that no one will doubt that the car is a great danger to others and road users. And since it is not yet possible to completely avoid traffic accidents, the car is being improved in the direction of reducing the likelihood of an accident and minimizing its consequences. This is facilitated by the tightening of vehicle safety requirements by organizations involved in analysis and practical experiments (crash tests). And such measures give their positive "fruits". Every year the car becomes safer - both for those who are inside it, and for pedestrians. To understand the components of the concept of "car safety", we first divide it into two parts - ACTIVE and PASSIVE safety.
ACTIVE SAFETY
What is ACTIVE VEHICLE SAFETY?
In scientific terms, this is a set of design and operational properties of a car aimed at preventing traffic accidents and eliminating the prerequisites for their occurrence associated with design features car.
And to put it simply, these are the car systems that help in preventing an accident.
Below - more details about the parameters and systems of the car that affect its active safety.
1. RELIABILITY
The failure-free operation of components, assemblies and systems of a vehicle is a determining factor in active safety. Particularly high requirements are placed on the reliability of the elements associated with the implementation of the maneuver - the brake system, steering, suspension, engine, transmission, and so on. Increasing the reliability is achieved by improving the design, the use of new technologies and materials.
2. VEHICLE LAYOUT
The layout of cars is of three types:
A) Front motor- the layout of the car, in which the engine is located in front of the passenger compartment. It is the most common and has two options: rear wheel drive (classic) And front wheel drive. The last lineup - front-engine front-wheel drive- is now widely used due to a number of advantages over the drive to rear wheels:
- better stability and control when driving at high speed, especially in wet and slippery road;
- providing the necessary weight load on the driving wheels;
- lower noise level, which is facilitated by the absence of a cardan shaft.
In the same time front wheel drive cars also have a number of disadvantages:
- at full load, acceleration on the rise is lost and wet road;
- at the moment of braking, too uneven distribution of weight between the axles (70% -75% of the vehicle's weight falls on the wheels of the front axle) and, accordingly, the braking forces (see Braking properties);
- the tires of the front driving steered wheels are loaded more, respectively, more prone to wear;
- drive to the front wheels requires the use of complex narrows - hinges of equal angular velocities(SHRUS)
- combination of the power unit (engine and gearbox) with final drive complicates access to individual elements.
b) Layout with central engine location - the engine is located between the front and rear axles, for passenger cars is quite rare. It allows you to get the most roomy interior for given dimensions and good distribution along the axes.
V) rear engine- the engine is located behind the passenger compartment. This arrangement has been extended to small cars. When transmitting torque to the rear wheels, it made it possible to obtain an inexpensive power unit and the distribution of such a load on the axles, in which the rear wheels accounted for about 60% of the weight. This had a positive effect on the cross-country ability of the car, but negatively on its stability and controllability, especially on high speeds. Cars with this layout, at present, are practically not produced.
3. BRAKING PROPERTIES
The ability to prevent accidents is most often associated with intensive braking, so it is necessary that the braking properties of the car ensure its effective deceleration in all traffic situations.
To fulfill this condition, the force developed by the brake mechanism must not exceed the adhesion force with the road, which depends on the weight load on the wheel and the condition pavement. Otherwise, the wheel will lock up (stop rotating) and begin to slide, which can lead (especially when several wheels are blocked) to skid the car and significantly increase the braking distance. To prevent blocking, the forces developed by the brake mechanisms must be proportional to the weight load on the wheel. This is realized through the use of more efficient disc brakes.
On modern cars used anti-lock system(ABS), which corrects the braking force of each wheel and prevents them from slipping.
In winter and summer, the condition of the road surface is different, so for best implementation braking properties Tires that are appropriate for the season must be used.
4. TRACTION PROPERTIES
Traction properties (traction dynamics) of the car determine its ability to intensively increase the speed. The confidence of the driver when overtaking, passing crossroads largely depends on these properties. Traction dynamics is especially important for emergency situations when it is too late to slow down and it is not possible to maneuver difficult conditions, and you can avoid an accident only by being ahead of the events.
As with braking forces, the traction force on the wheel should not be greater than the traction force, otherwise it will begin to slip. Prevents it traction control(PBS). When the car accelerates, it slows down the wheel, the rotation speed of which is greater than that of the others, and, if necessary, reduces the power developed by the engine.
5. VEHICLE STABILITY
Stability - the ability of a car to keep moving along a given trajectory, opposing the forces that cause it to skid and roll over in various road conditions at high speeds.
There are the following types of sustainability:
- transverse during rectilinear movement (course stability).
Its violation is manifested in the yaw (change of direction) of the car along the road and can be caused by the action of the lateral force of the wind, different sizes traction or braking forces on the wheels of the left or right side, their slipping or sliding. large play in steering, incorrect wheel alignment, etc .;
- transverse during curvilinear motion.
Its violation leads to skidding or overturning under the action of centrifugal force. An increase in the position of the center of mass of the car especially worsens stability (for example, a large mass of cargo on a removable roof rack);
- longitudinal.
Its violation is manifested in the slipping of the drive wheels when overcoming long icy or snowy slopes and the car sliding back. This is especially true for road trains.
6. DRIVABILITY OF THE VEHICLE
Handling - the ability of the car to move in the direction set by the driver.
One of the characteristics of handling is understeer - the ability of a car to change direction when the steering wheel is stationary. Depending on the change in the turning radius under the influence of lateral forces (centrifugal force on a turn, wind force, etc.), understeer can be:
- insufficient- the car increases the turning radius;
- neutral- turning radius does not change;
- excess- the turning radius is reduced.
Distinguish tire and roll understeer.
Tire steering
Tire steering is related to the property of tires to move at an angle to given direction with side slip (displacement of the contact patch with the road relative to the plane of rotation of the wheel). If you install tires of a different model, the understeer may change and the car is cornering when driving with high speed will behave differently. In addition, the amount of side slip depends on the pressure in the tires, which must correspond to that specified in the vehicle's operating instructions.
Roll Steering
Roll oversteer is due to the fact that when the body tilts (roll), the wheels change their position relative to the road and the car (depending on the type of suspension). For example, if the suspension is double-wishbone, the wheels lean in the direction of the roll, increasing the slip.
7. INFORMATION
Informativity - the property of the car to provide the necessary information to the driver and other road users. Insufficient information from other vehicles on the road about the condition of the road surface, etc. often causes accidents. The information content of the car is divided into internal, external and additional.
Internal provides the driver with the opportunity to perceive the information necessary for driving a car.
It depends on the following factors:
- Visibility should allow the driver to receive all the necessary information about the traffic situation in a timely manner and without interference. Faulty or inefficiently operating washers, windshield and heating systems, windshield wipers, lack of regular rear-view mirrors sharply impair visibility under certain road conditions.
- Instrument panel position, buttons and control keys, gear lever, etc. should provide the driver with a minimum amount of time to control indications, actions on switches, etc.
External informativeness- providing other road users with information from the car, which is necessary for proper interaction with them. It includes an external light signaling system, sound signal, dimensions, shape and color of the body. The information content of passenger cars depends on the contrast of their color relative to the road surface. According to statistics, cars painted in black, green, gray and blue colors, are twice as likely to get into accidents due to the difficulty of distinguishing them in conditions insufficient visibility and at night. Faulty direction indicators, brake lights, parking lights won't let other members traffic recognize the driver's intentions in time and make the right decision.
Additional information content- property of the car, allowing to operate it in conditions limited visibility: at night, in fog, etc. It depends on the characteristics of lighting fixtures and other devices (e.g. fog lights), improving the driver's perception of information about the traffic situation.
8. COMFORTABILITY
The comfort of the car determines the time during which the driver is able to drive the car without fatigue. An increase in comfort is facilitated by the use of automatic transmission, speed controllers (cruise control), etc. At present, cars are produced equipped with adaptive cruise control. It not only automatically maintains the speed at a given level, but also, if necessary, reduces it up to a complete stop of the car.
PASSIVE SAFETY
The passive safety of the car must ensure the survival and minimization of the number of injuries to the passengers of the car involved in a traffic accident.
IN last years passive safety of cars has become one of the the most important elements from a manufacturers point of view. Huge amounts of money are invested in the study of this topic and its development, and not only because companies care about the health of customers, but because safety is a selling lever. Companies love to sell.
I will try to explain a few definitions hidden under the broad definition " passive safety».
It is divided into external and internal.
External achieved by exclusion on the outer surface of the body sharp corners, protruding handles, etc. With this, everything is clear and quite simple.
To level up internal security use a lot of different design solutions:
1. BODY STRUCTURE or "SAFETY GRILLE"
It provides acceptable loads on the human body from a sharp deceleration in an accident and saves the space of the passenger compartment after the deformation of the body.
In a severe accident, there is a risk that the engine and other components can enter the driver's cab. Therefore, the cabin is surrounded by a special "safety grid", which is an absolute protection in similar cases. The same stiffening ribs and bars can be found in the doors of the car (in case of side collisions).
This also includes energy repayment areas.
In a severe accident, there is a sharp and unexpected deceleration to a complete stop of the car. This process causes huge overloads on the bodies of passengers, which can be fatal. It follows from this that it is necessary to find a way to "slow down" the deceleration in order to reduce the load on the human body. One way to solve this problem is to design areas of destruction that dampen the energy of a collision in the front and rear parts of the body. The destruction of the car will be more severe, but the passengers will remain intact (and this is compared to the old "thick-skinned" cars, when the car got off with a "light fright", but the passengers received severe injuries).
2. SEAT BELTS
The belt system, so familiar to us, is undoubtedly the most in an efficient way human protection during an accident. After many years, during which the system remained unchanged, in recent years there have been significant changes that have increased the safety of passengers. Thus, the belt pretensioner system in the event of an accident draws the human body to the back of the seat, thereby preventing the body from moving forward or slipping under the belt. The effectiveness of the system is due to the fact that the belt is in a taut position, and not weakened by the use of various clips and clothespins, which practically cancel the action of the pretensioner. Optional element seat belt pretensioner is a restraint system maximum load on the body. When it is triggered, the belt will loosen slightly, thereby reducing the load on the body.
3. INFLATABLE AIRBAGS(airbag)
One of the most common and effective safety systems in modern cars (after seat belts) are air cushions. They began to be widely used already in the late 70s, but it was not until a decade later that they really took their rightful place in the safety systems of most manufacturers' cars.
They are placed not only in front of the driver, but also in front of the front passenger, as well as from the sides (in the doors, pillars, etc.). Some car models have them forced shutdown due to the fact that people with a sick heart and children may not be able to withstand their false alarm.
4. SEATS WITH HEADRESTS
I think that no one will have any doubts The role of the head restraint is to prevent sudden movement of the head during an accident. Therefore, you should adjust the height of the head restraint and its position to the correct position. Modern head restraints have two degrees of adjustment to prevent injuries to the cervical vertebrae during the “overlapping” movement, which are so characteristic of rear-end collisions.
5. CHILD SAFETY
Today it is no longer necessary to puzzle over the adjustment of the child seat to original belts security. Increasingly common device Isofix allows you to attach the child safety seat directly to the connection points prepared in advance in the car, without using seat belts. It is only necessary to check that the vehicle and child seat adapted to fixtures Isofix.
TO category:
Driving a car
Active and passive safety
One of the factors that ensure road safety is the active and passive safety of cars. The active safety of cars is understood as the absence of sudden failures in its structural systems associated with the ability to maneuver and control confidence in any road conditions and in any situation. It depends on the braking and traction dynamics of the vehicle. The first determines the value stopping way, which should be minimal; the second gives the driver confidence when overtaking, passing intersections and crossing highways, exit from emergency when it's too late to stop.
The main design characteristics of the car include: layout, stability, that is, the ability to resist skidding and rollover in various road conditions and at high speeds; manageability - operational property a car that allows you to drive a car with the least expenditure of mental and physical energy when making maneuvers; maneuverability - characterized by the value of the smallest turning radius and the dimensions of the car; stabilization - the ability of the elements of the system itself car - driver - road to resist the unstable movement of the car or with the help of the driver to maintain the optimal position of the natural axes of the car when driving; brake system, to ensure the reliability of which are adopted separate drives to the front and rear wheels; automatic regulation of gaps in the system, providing a stable response time, blocking devices to prevent skidding during braking; steering, which should provide a constant reliable connection with the steering wheel and the area of contact of the tire with the road three little muscle effort of the driver; correct installation managers - wheels of cars; reliable tires that significantly increase the safety of the car; reliability of signaling and lighting systems.
The correctness and timeliness of the assessment by the driver road conditions are largely determined by such vehicle characteristics as visibility, efficiency of head lighting systems, cleaning, washing and heating of the windshield, rear and side windows.
The reliability of the driver's work during long-term driving depends on a comfortable cab, assessed by the microclimate, sound insulation, comfortable seats and use of control devices, lack of harmful vibrations. In addition, the standardization of the location and operation of controls on all vehicles is of no small importance for the reliability of the driver's work.
Improvement of the above design characteristics cars are engaged in the designers of manufacturers and research institutes.
Security questions car traffic cannot be solved only by improving the design of cars without taking into account the interaction of all factors that arise during movement. Therefore, the task of passive safety is to save human life, as well as reduce the number and severity of injuries in various traffic accidents. Working to improve passive safety, designers seek to provide a protective zone around each passenger, limit the movement of the driver and passengers relative to the seat, reduce the level of injury from impacts on the internal surfaces of the passenger compartment of the body, as well as the loads acting on the passenger, take measures to reduce the likelihood of injury in post-accident situation, provide a convenient way out of the car that has suffered an accident.
Therefore, the design goal safe car- creation of such internal and external constructive device, which would help the driver and passengers to withstand the high overloads that occur during traffic accidents. To do this, the steering wheel and column must move and absorb the impact energy (telescopic), the ejection of passengers must be excluded; all passengers must have individual protective and restraining equipment; there should be no sharp and protruding parts in front of the passengers, window glass should be as flexible as possible so as not to hurt the head, etc.
One of the major occupant safety concerns is reducing the decelerations experienced by occupants on impact. In any car collision, if the passenger has freedom of movement in the cabin, he continues to move forward under the influence of inertia forces at the speed that the car had at the time of the impact, and therefore hits the details of the interior of the cabin already at the time when the car stopped .
To prevent serious consequences in the event of a collision, safety belts (seat belts) are used, which are attached to the seats and pillars of the cab (body). It must be remembered that the presence of a gap between the belt and passengers causes a sharp belt tension at the initial moment of impact of the car, as a result of which the latter may break and impacts on Windshield or more details. During the reentry phase of a vehicle impact, the occupant returns abruptly to the seat, causing the head to tip backwards under the force of the energy forces. The spine and nerve centers are seriously damaged. This can be eliminated by using head restraints rigidly connected to the seat back. How passive safety measures are applied airbags, safe steering wheel, windshield, etc.
Moscow State
Automobile and Road Institute
(Technical University)
CORRESPONDENCE FACULTY
SUMMARY on the course
"Organization of road transport and traffic safety"
ON THE TOPIC
« Passive vehicle safety»
Completed by student Kharchenko V.L.
Group 3 ZPs
Checked Belyaev Vladimir Mikhailovich
MOSCOW 2009
Introduction
2. Seat belts
3. Airbags
4. Headrests
5. Safety steering mechanism
6. Emergency exits
Conclusion
Literature
INTRODUCTION
A modern car by its nature is a device of increased danger. Considering the social significance of the car and its potential danger during operation, manufacturers equip their cars with means that contribute to its safe operation. From the complex of means with which a modern car is equipped, passive safety means are of great interest. The passive safety of the car must ensure the survival and minimization of the number of injuries to the passengers of the car involved in a traffic accident.
In recent years, the passive safety of cars has become one of the most important elements in terms of manufacturers. Huge amounts of money are invested in the study of this topic and its development due to the fact that companies care about the health of customers.
I will try to explain a few definitions hidden under the broad definition of "passive safety".
It is divided into external and internal.
The internal includes measures to protect people sitting in the car through special interior equipment. External passive safety includes measures to protect passengers by giving the body special properties, for example, the absence of sharp corners, deformation.
Passive safety - a set of components and devices that allow you to save the life of car passengers in case of an accident. Includes, among other things:
1.Airbags;
2. crushable or soft elements of the front panel;
3.folding steering column;
4.travmobezopasny pedal assembly - in the event of a collision, the pedals are separated from the attachment points and reduce the risk of damage to the driver's legs;
5.inertial seat belts with pretensioners;
6.Energy-absorbing front and rear parts car, crushed upon impact - bumpers;
7.seat headrests - protect the passenger's neck from serious injuries when the car hits from behind;
8.safety glasses: tempered, which, when broken, shatter into many non-sharp fragments and triplex;
9.roll bars, reinforced A-pillars and upper windshield frame in roadsters and convertibles, transverse bars in the doors.
1. BODY
It provides acceptable loads on the human body from a sharp deceleration in an accident and saves the space of the passenger compartment after the deformation of the body.
In a severe accident, there is a risk that the engine and other components can enter the driver's cab. Therefore, the cabin is surrounded by a special "safety grid", which is an absolute protection in such cases. The same stiffening ribs and bars can be found in the doors of the car (in case of side collisions). This also includes areas of energy repayment.
In a severe accident, there is a sharp and unexpected deceleration to a complete stop of the car. This process causes huge overloads on the bodies of passengers, which can be fatal. It follows from this that it is necessary to find a way to "slow down" the deceleration in order to reduce the load on the human body. One way to solve this problem is to design areas of destruction that dampen the energy of a collision in the front and rear parts of the body. The destruction of the car will be more severe, but the passengers will remain intact (and this is compared to the old "thick-skinned" cars, when the car got off with a "light fright", but the passengers received severe injuries).
The design of the body provides that in the event of a collision, the parts of the body are deformed, as it were, separately. Plus, high-tensioned metal sheets are used in the design. This makes the car more rigid, and on the other hand allows it to be not so heavy.
2. SEAT BELTS
At first, cars were equipped with two-point belts that “held” riders by the stomach or chest. Less than half a century later, engineers realized that the multi-point design is much better, because in a crash it allows you to distribute the pressure of the belt on the surface of the body more evenly and significantly reduce the risk of injury to the spine and internal organs. In motorsport, for example, four-, five- and even six-point seat belts are used - they keep the person in the seat “tightly”. But on the “citizen”, because of their simplicity and convenience, three-point ones took root.
In order for the belt to work properly for its purpose, it must fit snugly against the body. Formerly belts I had to adjust, adjust according to the figure. With the advent of inertial belts, the need for “manual adjustment” has disappeared - in the normal state, the coil rotates freely, and the belt can wrap around a passenger of any build, it does not hinder actions, and every time a passenger wants to change the position of the body, the strap always fits snugly to the body. But at the moment when "force majeure" comes - inertial coil immediately fix the belt. In addition, on modern machines, squibs are used in belts. Small explosive charges detonate, pulling the belt, and he presses the passenger to the back of the seat, preventing him from hitting.
Seat belts are one of the most effective means accident protection.
Therefore, passenger cars must be equipped with seat belts if attachment points are provided for this. The protective properties of belts largely depend on their technical condition. Belt malfunctions, in which the vehicle is not allowed to be operated, include tears and abrasions of the fabric tape of the straps visible to the naked eye, unreliable fixation of the tongue of the strap in the lock or the absence of automatic ejection of the tongue when the lock is unlocked. For inertia-type seat belts, the webbing should be freely retracted into the reel and blocked when the car is moving sharply at a speed of 15-20 km / h. Belts that have experienced critical loads during an accident in which the car body has received serious damage are subject to replacement.
3. AIRBAGS
One of the most common and effective safety systems in modern cars (after seat belts) are airbags. They began to be widely used already in the late 70s, but it was not until a decade later that they really took their rightful place in the safety systems of most manufacturers' cars.
They are placed not only in front of the driver, but also in front of the front passenger, as well as from the sides (in the doors, pillars, etc.). Some car models have their forced shutdown due to the fact that people with heart problems and children may not be able to withstand their false operation.
Today, airbags are commonplace not only in expensive cars, but also on small (and relatively inexpensive) cars. Why are airbags needed? And what are they?
Airbags have been developed for both drivers and passengers on front seat. For the driver, the pillow is usually installed on the steering, for the passenger - on the dashboard (depending on the design).
The front airbags are deployed when an alarm is received from the control unit. Depending on the design, the degree of filling of the pillow with gas may vary. The purpose of the front airbags is to protect the driver and passenger from injury by solid objects (engine body, etc.) and glass fragments in frontal collisions.
Side airbags are designed to reduce damage to vehicle occupants in a side impact. They are installed on the doors or in the backs of the seats. In a side collision external sensors send signals to the central airbag control unit. This makes it possible for some or all of the side airbags to deploy.
Here is a diagram of how the airbag system works:
Studies of the effect of airbags on the likelihood of driver death in frontal collisions have shown that it is reduced by 20-25%.
If the airbags have deployed or been damaged in any way, they cannot be repaired. The entire airbag system must be replaced.
The driver's airbag has a volume of 60 to 80 liters, and the front passenger - up to 130 liters. It is easy to imagine that when the system is triggered, the interior volume decreases by 200-250 liters within 0.04 seconds (see figure), which gives a considerable load on the eardrums. In addition, a pillow flying at a speed of more than 300 km / h is fraught with a considerable danger to people if they are not fastened with a seat belt and nothing delays the inertial movement of the body towards the pillow.
There are statistics that speak about the impact inflatable pillows safety for injury in an accident. What can be done to reduce the chance of injury?
If your car has an airbag, do not place rear-facing child seats on a vehicle seat where the airbag is located. When inflated, the airbag may move the seat and cause injury to the child.
Airbags in the passenger seat increase the risk of death for children under the age of 13 sitting in that seat. A child less than 150 cm tall can be hit in the head by an air bag that opens at a speed of 322 km/h.
4. HEADRESTS
The role of the head restraint is to prevent sudden movement of the head during an accident. Therefore, you should adjust the height of the head restraint and its position to the correct position. Modern head restraints have two degrees of adjustment to prevent injuries to the cervical vertebrae during the “overlapping” movement, which are so characteristic of rear-end collisions.
Effective protection when using a head restraint can be achieved if it is located exactly on the center line of the head at the level of its center of gravity and no more than 7 cm from the back of it. Be aware that some seat options change the size and position of the head restraint.
5. SAFETY STEERING GEAR
Crash-safe steering is one of the constructive measures that ensure the passive safety of the car - the ability to reduce the severity of the consequences of traffic accidents. The steering gear can cause serious injury to the driver in a frontal collision with an obstacle when the front of the vehicle is crushed when the entire steering gear moves towards the driver.
The driver may also be injured by the steering wheel or steering shaft when moving forward suddenly due to frontal collision when, with a weak seat belt tension, the movement is 300 ... 400 mm. To reduce the severity of injuries sustained by the driver in frontal collisions, which account for about 50% of all traffic accidents, various designs of safety steering mechanisms are used. To this end, in addition to the steering wheel with a recessed hub and two spokes, which can significantly reduce the severity of injuries on impact, a special energy-absorbing device is installed in the steering mechanism, and the steering shaft is often made composite. All this provides a slight movement of the steering shaft inside the car body in frontal collisions with obstacles, cars and other vehicles.
Other energy-absorbing devices that connect composite steering shafts are also used in safety steering controls of passenger cars. These include rubber couplings of a special design, as well as devices of the "Japanese flashlight" type, which is made in the form of several longitudinal plates welded to the ends of the connected parts of the steering shaft. In collisions, the rubber clutch is destroyed, and the connecting plates are deformed and reduce the movement of the steering shaft inside the body.
The main elements of a wheel assembly are a rim with a disk and a pneumatic tire, which can be tubeless or consist of a tire, a tube and a rim tape.
6. EMERGENCY EXITS
Roof hatches and windows of buses can be used as emergency exits for quick evacuation of passengers from the passenger compartment in case of an accident or fire. For this purpose, inside and outside the passenger compartment of buses, special means are provided for opening emergency windows and hatches. So, glasses can be installed in the window openings of the body on two locking rubber profiles with a locking cord. In case of danger, it is necessary to pull out the lock cord using the bracket attached to it, and squeeze out the glass. Some windows are hung in the opening on hinges and are provided with handles for opening them outward.
Devices for actuation emergency exits Buses in service must be in working condition. However, during the operation of buses, ATP employees often remove the bracket on emergency windows, fearing deliberate damage to the window seal by passengers or pedestrians in cases where this is not dictated by necessity. Such "prudence" makes it impossible for emergency evacuation of people from buses.
CONCLUSION
Ensuring the good condition of the structural elements of the car, the requirements for which were considered earlier, can reduce the likelihood of an accident. However, it has not yet been possible to create absolute safety on the roads. That is why specialists in many countries pay great attention to the so-called passive car safety, which makes it possible to reduce the severity of the consequences of an accident.
LITERATURE
1. www. anytyres. en
2. www. transserver. en
3. Theory and design of the car and engine
Vakhlamov V.K., Shatrov M.G., Yurchevsky A.A.
4. Organization of road transport and traffic safety 6 studies. allowance for students of higher education. institutions / A.E. Gorev, E.M. Oleshchenko .- M .: Publishing Center "Academy". 2006.(p.187-190)
Passive safety is a set of systems installed in a car that reduce the consequences of a traffic accident for the driver and passengers. Conventionally, they can be divided into constructive and operational elements of passive safety. The former include various elements of the car structure, which reduce the degree of deformation of the body upon impact or prevent damage to passengers, disabling the components and assemblies of the car ( steering column, engine). The second includes airbags and seat belts, which reduce the traumatic consequences of accidents.
Structural passive safety systems appeared in cars earlier than operational ones. Constructors automotive companies, examining the damage to the bodies of cars that suffered in an accident, they came to the conclusion that vehicles need to be strengthened both from the inside and outside. The first element of passive safety " iron horses» steel bumpers - bars mounted on springy brackets on the front and rear of the car and absorbing impact energy.
They were first installed in 1898 on the President car, and these passive safety elements began to be used serially on Ford models Model A. Over the years, bumpers improved, became less heavy and were made not of metal, albeit protected by rubber pads, but of plastic.
In addition to installing bumpers, the designers mounted steel plates on the front and rear of the auto body, which protected vehicle from deformation upon impact from the front or rear. Such an element of passive safety is also used on modern cars.
Another element of passive safety, which appeared at the dawn of the automotive industry - steel anti-shock cross beams installed in the doors. With these bars, engineers reinforced the design of the side doors, which were less deformed during a side impact than doors without such elements. For the first time, such designs began to be used on cars in the mid-1930s and gradually, having proved their necessity, they began to be installed on everyone without exception. cars. At the same time, the designers worked on and determined the deformation zones of the body - places in the body that were deformed during side, front, rear impacts or rollover of the car, absorbing the impact energy and allowing you to save the car interior and passengers sitting in it from significant damage. The first cars in which the technology of deformation zones of the body was implemented left the assembly line Mercedes-Benz in the 1950s.
TO structural elements passive safety, in addition to the above, also includes a safety steering column and pedal assembly, soft parts of the front panel, reinforced front pillars, the Sandwich Panel system (ensures that the engine leaves under the bottom of the car in a frontal impact) and safety glass.
Tramobezopasnaya steering column has a telescopic mechanism, which in the event of a frontal impact, the column folds into the front panel, thus preventing damage to the chest of the driver. The pedal assembly with the same impact works like this: the brake, gas and clutch pedals fly off the mounts, reducing the risk of breaking the driver's legs. soft details dashboard during a frontal impact, they are crushed without causing damage to the driver and passengers, and special tempered glass when broken, they shatter into many fragments with blunt edges. Triplex ( laminated glass) with such an impact, it retains the structure of the glass, becoming covered with a web of cracks - which is why this particular glazing material is mainly used on modern cars. Finally, the so-called sandwich panel system allows, in a frontal impact, to shift the engine under the bottom of the car, preventing it from entering the passenger compartment.
The first elements of operational passive safety were belts, which began to be used on cars at the beginning of the 20th century. They allow you to keep the human body in an accident in a chair, preventing contact with the steering column. The first seat belts were two-point (attached to the seat frame in two dreams), in the process of developing safety technology, the number of attachment points grew.
An evolutionary step in the development of seat belt design was the use of inertial mechanism and pretensioners, which during a collision regulate the force of keeping the body of drivers and passengers in the seat. According to statistics, it was seat belts that saved more lives (70%) than pillows (20%). By the way, the first airbags began to be used in cars in the late 1960s on cars Chrysler, but these elements did not have popularity, since the percentage of deaths in cars equipped with pillows was still high.
Studies have shown that the effectiveness of airbags increases significantly if they are used in combination with seat belts - after all, an unfastened person in an accident receives a strong blow from an deployed airbag. Therefore, even 7 or 9 airbags installed in a car do not guarantee survival if the driver and passengers were not fastened. Today, there are not only interior (front, side, curtain type), but also external airbags that are installed in front of the car. In the event of a collision with a pedestrian, such an airbag inflates and cushions the impact, preventing the death of the pedestrian.
Finally, another element of operational passive safety is the head restraints, which are installed on the backs of the front and rear row seats. These devices help protect the neck of passengers and the driver in a rear impact. The first headrests were equipped with cars Mercedes-Benz brands. Structurally, these devices are divided into active (can be adjusted in height and angle) and fixed (rigidly built into the seat backs).
There are more and more cars on the roads, drive them in dense stream becomes more and more difficult. In addition, the movement takes part a large number of young drivers who do not have sufficient driving experience.
To assist the driver and to improve road safety, a large number of electronic systems car safety.
Automotive security systems
All security systems are divided into active and passive:
- appointment active systems– prevent car collisions;
- passive safety systems reduce the severity of the consequences of an accident.
This review is an attempt to list and characterize modern active safety systems.
1. (ABS, ABS). Prevents wheel slippage during vehicle braking. Often (but not always), ABS operation reduces braking distances vehicle, especially on slippery roads.
3. System emergency braking(EBA, BAS). In the event quickly raises the pressure in the brake system. used vacuum way management.
4. Dynamic braking control system (DBS, HBB). Raises pressure rapidly emergency braking, but the implementation method is different, hydraulic.
5. (EBD, EBV). In fact, this software extension latest generations ABS. The braking force is correctly distributed between the axles of the car, preventing blocking, in the first place, of the rear axle.
6. Electromechanical braking system (EMB). Brake mechanisms on wheels are activated by electric motors. On production cars not yet applied.
7. (ACC). Maintains the vehicle speed selected by the driver while maintaining safe distance to the vehicle in front. To maintain distance, the system can change the vehicle's speed by applying the brakes, or throttle valve engine.
8. (Hill Holder, HAS). When starting off on a hill, the system prevents the vehicle from rolling back. Even with the brake pedal released, the pressure in the brake system is maintained and begins to decrease when you press the "gas" pedal.
9. (HDS, DAC). Saves safe speed vehicle when driving downhill. Turned on by the driver, but activated at a certain steepness of the descent and enough low speed car.
10. (ASR, TRC, ASC, ETC,TCS). Prevents car wheels from slipping when accelerating.
11. (APD, PDS). Allows you to detect a pedestrian whose behavior may lead to a collision. In case of danger, it alerts the driver and turns on brake system.
12. (PTS, Park Assistant, OPS). Helps the driver to park the car in cramped conditions. Some types of systems perform this work in automatic or automated mode.
13. (Area View, AVM). With the help of a system of video cameras, or rather, an image synthesized from them on a monitor, it helps to drive a car in cramped conditions.
14. . Takes control of the car dangerous situation to get the car out of the way.
15. . Effectively keeps the vehicle in the lane marked by lane markings.
16. . Controlling the presence of interference in " dead zones» rear-view mirrors help you safely perform a lane change maneuver.
17. . With the help of video cameras that react to the thermal radiation of objects, an image is created on the monitor that helps to drive a car in low visibility.
18. . Reacts to speed limit signs, brings this information to the driver.
19. . Monitors the driver's condition. If, in the opinion of the system, the driver is tired, it requires a stop and rest.
20. . In the event of an accident, after the first collision, it activates the vehicle's braking system to avoid subsequent collisions.
21. . Observes the situation around the vehicle and, if necessary, takes measures to prevent an accident.
