Increasing the passive safety of the car by improving its structural elements. Modern car security systems What determines car safety

Scientists and automakers have compiled a rating of ways that can save life while driving. Before getting behind the wheel, familiarize yourself with the following six points that can improve vehicle safety. Introducing the top 6 best ways to improve car safety.

1. Steering wheel

If you sit very close to the steering wheel, then at the moment of impact, you will most likely hit the steering column before the airbag or belt tension is deployed. Therefore, adjust the seat so that you are as far from the steering wheel as possible, but at the same time do not reach for it with your hands. The arms should be only slightly bent at the elbows.

2. Headrest

For maximum safety, the top of the headrest should be at ear level, which is easy to see and adjust by looking in the rearview mirror. This measure will prevent a fracture of the cervical spine.

3. Lights

Here our dear traffic police inspectors, who have already made a point in the traffic rules, according to which it is necessary to turn on the headlights at any time of the day, went to meet you. According to some reports, this measure reduces the likelihood of a frontal collision by 5% and the likelihood of hitting a pedestrian by 12%.

4. Interior temperature

If you have a long trip, then you need to set the temperature a little lower than comfortable so that God forbid you do not fall asleep while driving. Periodically changing the interior temperature can also help.

5. Tires

You should monitor the condition of the tire, its wear and pressure. Worn out tire increases the braking distance many times, and insufficient pressure can cause a change in the trajectory of movement, the car swaying on the road, and the wheel is more likely to burst. Do you often hear on television the phrase: “Lost control” ?!

6. Cell phone

The question of whether a wireless headset is safer has also become a very controversial statement lately, so it is better to try to turn off your phone while driving. After all, life is more precious than a telephone conversation, isn't it?

So we looked at the top of the best ways to improve car safety. Good luck on the road and always come home!

In such a complex unit as a car, it is very easy to forget about one of the most basic systems - the protection and safety system. And if active safety is always covered in detail both by the media and by the dealers or sellers themselves, then passive safety is nothing more than a gray mouse inside a complex vehicle structure.

What is passive vehicle safety

Passive safety Is a set of properties and devices of a vehicle, which have their own unique design and operational differences, but are functionally aimed at ensuring the safest conditions in the event of an accident. In contrast to the active safety system, the action of which is aimed at saving the car from accidents, the car's passive safety system is activated after the accident has taken place.

In order to reduce the consequences of the accident, a whole set of devices is used, the purpose of which is to reduce the severity of the accident that has occurred. For a more accurate classification, a division into two main groups is used:

Internal system - it includes:

Airbags
Seat belts
Seat construction (headrests, armrests, etc.)
Body energy absorbers
Other soft interior elements

External system - another, no less important group, is presented in the form:

Bumpers
Body protrusions
Glass
Rack amplifiers

Recently, on the pages of well-known news agencies, they began to cover in detail the points that report on all the elements of passive safety in the car. In addition, we should not forget the activities of the independent organization Euro NCAP (European New Car Assessment Program). This committee has been conducting crash tests on all models entering the market for quite some time, awarding a statement of the results of testing both active safety systems and passive ones. Anyone can get acquainted with the data on the results of crash tests, making sure of each of the components of the protection system.

The image demonstrates how all passive safety systems work in harmony during an emergency (seat belts, airbags, seat with headrest).

Internal passive safety

All the elements of passive safety included in this list are designed to protect everyone in the passenger compartment of a car that has an accident. That is why, it is very important, in addition to equipping the car with special equipment (in a working condition), it must be used by all participants in the ride for its intended purpose. Only compliance with all the rules will allow you to get the highest protection. Next, we will consider the most basic points that are included in the list of internal passive safety.

The body is the basis of the entire security system. The strength of the car and possible deformations of its parts directly depend on the material, condition, and also the design features of the car body. To protect passengers from getting the engine compartment contents into the cabin, the designers specifically use a "safety grill" - a solid layer that does not allow the cabin base to be disturbed.
The safety of the cabin from structural elements is a whole list of devices and technologies that are designed to protect the health of the driver and passengers. For example, many salons provide for a folding steering wheel, which does not allow additional damage to the driver. In addition, modern cars are equipped with a trauma-safe pedal assembly, the action of which provides for the detachment of the pedals from the mounts, reducing the load on the lower limbs.

To count on maximum safety when using the headrest, you need to very clearly set its position to a certain height that suits you.

Seat belts - from the accepted standard of 2-point lap belts, which held the passenger with a usual tie through the stomach or chest, were abandoned back in the middle of the last century. Passive restraints like these required improvements that came in the form of multi-point belts. The increased functionality of this type of device made it possible to evenly distribute the kinetics throughout the body, without exposing individual areas of the body to trauma.
Airbags are the second most important (the first line is confidently held by safety belts), a passive safety system. Having received recognition in the late 70s. they are tightly included in all vehicles. The modern car industry began to be equipped with a whole set of airbag systems that surround the driver and passengers from all sides, blocking potential damage zones. The sharp opening of the chamber with the storage of the pillow activates the rapid filling of the last air mixture, which absorbs the person approaching by inertia.
Seats and Headrests - The seat itself does not provide any additional functions during an accident other than securing the passenger in place. However, the head restraints, on the contrary, open their functionality just at the moment of collision, preventing the head from tipping back with subsequent trauma to the cervical vertebrae.
Other means of internal passive safety - many vehicles provide for the presence of highly stressed metal sheets. This upgrade makes the vehicle more impact-resistant while reducing weight. Many cars also use an active system of areas of destruction, which in a collision extinguish the resulting kinetics, while they themselves are destroyed (increased vehicle destruction is nothing in comparison with human life and health).

Using the example of the small body frame of the Smart car, one can see how passive safety plays a fundamental role even at the design stage of the future car.

External passive safety

If in the previous paragraph we considered the means and devices of the car that protect passengers and drivers at the time of the accident, then this time we will talk about a complex that allows you to maximally protect the health of a pedestrian who has fallen under the wheels of the car in question.

Bumpers - the design of modern bumpers includes several energy and kinetic absorbing elements, which are present both on the front of the car and at the rear. Their purpose is to absorb the energy arising from the impact due to the blocks subject to crushing. This not only allows you to reduce the risk of injury to a pedestrian, but also greatly reduces damage to the interior of the car.
External protrusions of cars - as a rule, it is difficult to attribute to the useful properties of such elements. However, as it may seem at first glance, most of these elements have a similar principle of self-destruction described earlier in paragraph 6. of the section "Internal passive safety".
Pedestrian protection devices - individual manufacturers such as Bosch, Siemens, TRW and others have been actively developing systems for additional safety for pedestrians in road accidents for several decades. For example, the Electronic Pedestrian Protection system will raise the hood roof, increasing the area of \u200b\u200bcollision with the pedestrian's body, while acting as a "shield" from the harder and uneven parts of the engine compartment.

Ministry of Education and Science

Russian Federation

State educational institution of higher

vocational education

CONTROL WORK No. 1, No. 2

in the discipline "Safety of vehicles"

Active and passive vehicle safety

Introduction

1 Vehicle specifications

2 Active vehicle safety

3 Passive vehicle safety

4 Environmental safety of the car

Conclusion

Literature

INTRODUCTION

A modern automobile is inherently a hazardous device. Taking into account the social significance of the car and its potential danger during operation, manufacturers equip their cars with tools that contribute to its safe operation. Of the complex of means with which a modern car is equipped, passive safety means are of great interest. Passive vehicle safety must ensure the survival and minimization of the number of injuries to the passengers of the vehicle involved in a road traffic accident.

AT last years passive vehicle safety has become one of the most important elements from the point of view of manufacturers. A lot of money is 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 subdivided into external and internal.

Internal measures include measures to protect people sitting in the car by special equipment salon. External passive safety includes measures to protect passengers by giving the body special properties, for example, the absence of sharp corners, deformation.

Passive safety is a set of units and devices that allow you to save the life of car passengers in an accident. Includes, but is not limited to:

1. airbags;

2. crushing or soft elements of the front panel;

3. a folding steering column;

4.trauma-safe pedal assembly - in a collision, the pedals are separated from the attachment points and reduce the risk of injury to the driver's legs;

5.inertial seat belts with pretensioners;

6.Energy absorbing elements of the front and rear parts of the car, crumpled upon impact - bumpers;

7. seat head restraints - protect the passenger's neck from serious injuries when the car is struck from behind;

8.safe glasses: tempered, which, when broken, crumble into many mild fragments and triplex;

9.Roadsters, reinforced A-pillars and upper windshield frame in roadsters and convertibles, crossbars in the doors.

1 Technical characteristics of the car GAZ-66-11

Table 1 - Characteristics of GAZ - 66 - 11

Automobile model	GAZ - 66 - 11
Year of issue	1985 - 1996
Dimensional parameters, mm
Length	5805
Width	2322
Height	2520
Base	3300
Track, mm
Front wheels	1800
Rear wheels	1750
Weight characteristics
Curb weight, kg	3640
Loading capacity, kg	2000
Full weight, kg	3055
Speed \u200b\u200bcharacteristics
Maximum speed, km / h	90
Acceleration time to 100 km / h, sec	there is no data
Brakes
Front axle	Drum type with internal pads. Diameter 380 mm, lining width 80 mm.
Rear axle

Table 2. - Values \u200b\u200bof steady-state deceleration.

2 Active vehicle safety

Scientifically speaking, it is a set of structural and operational properties of a car aimed at preventing road accidents and eliminating the prerequisites for their occurrence associated with design features car.

Simply put, these are the systems in the car that help prevent accidents.

RELIABILITY

Reliability of components, assemblies and systems of the car is a determining factor active safety... Particularly high demands are placed on the reliability of elements related to the implementation of the maneuver - the braking system, steering, suspension, engine, transmission, and so on. Increased reliability is achieved by improving the design, using new technologies and materials.

CAR LAYOUT

There are three types of vehicle layout:

a) Front-engine - vehicle layout 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 type of layout - front-engine front-wheel drive - is now widespread due to a number of advantages over the drive on rear wheels:

Better stability and handling when driving at high speed, especially on wet and slippery roads;

Ensuring the required weight load on the driving wheels;

Less noise, which is facilitated by the absence of a propeller shaft.

At the same time, front-wheel drive cars have a number of disadvantages:

Under full load, acceleration on the rise and on wet roads deteriorates;

At the moment of braking, the distribution of weight between the axles is too uneven (the wheels of the front axle account for 70% -75% of the weight of the car) and, accordingly, of the braking forces (see Braking Properties);

The tires of the front driving steered wheels are loaded more and are therefore more prone to wear;

Front-wheel drive requires the use of complex units - constant velocity joints (CV joints)

The combination of the power unit (engine and gearbox) with the final drive makes it difficult to access individual elements.

b) Mid-engine layout - the engine is located between the front and rear axles, for passenger cars is quite rare. It allows you to get the most spacious interior for the given dimensions and good distribution along the axes.

c) Rear-engined - the engine is located behind the passenger compartment. This arrangement was common in small cars. When transmitting torque to the rear wheels, it made it possible to obtain an inexpensive power unit and to distribute such a load along the axles, in which the rear wheels accounted for about 60% of the weight. This had a positive effect on the vehicle's cross-country ability, but negatively on its stability and handling, especially at high speeds. Cars with this layout, at present, are practically not produced.

BRAKE PROPERTIES

The ability to prevent accidents is most often associated with heavy braking, therefore, it is necessary that the braking properties of the car provide its effective deceleration in all traffic situations.

To fulfill this condition, the force developed by the braking mechanism should not exceed the adhesion force with the road, which depends on the weight load on the wheel and the condition of the road surface. Otherwise, the wheel will block (stop rotating) and begin to slip, which can lead (especially when several wheels are blocked) to the car skidding and a significant increase in the braking distance. To prevent blocking, the forces generated by the brakes must be proportional to the weight load on the wheel. This is realized by using more efficient disc brakes.

Modern cars use anti-lock braking 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, therefore, for the best implementation of the braking properties, it is necessary to use tires that are appropriate for the season.

TRACTION PROPERTIES

The traction properties (traction dynamics) of a car determine its ability to rapidly increase its speed. The driver's confidence in overtaking and crossing intersections largely depends on these properties. Traction dynamics is especially important for getting out of emergency situations, when it is too late to brake, difficult conditions do not allow maneuvering, and an accident can be avoided only by anticipating the event.

As in the case of braking forces, the traction force on the wheel should not be greater than the traction force, otherwise it will start to slip. This is prevented by the traction control system (PBS). When the car accelerates, it slows down the wheel, the rotation speed of which is higher than that of the others, and, if necessary, reduces the power developed by the engine.

STABILITY OF THE CAR

Stability - the ability of a car to maintain movement along a given trajectory, counteracting the forces that cause it to skid and roll over in various road conditions at high speeds.

The following types of resistance are distinguished:

Transverse with straight motion (directional stability).

Its violation is manifested in yawing (changing the direction of movement) of the car on the road and can be caused by the action of the lateral wind force, different values \u200b\u200bof traction or braking forces on the wheels of the left or right side, their slipping or sliding. large backlash in the steering, incorrect wheel alignment angles, etc.;

Transverse with curvilinear motion.

Its violation leads to skidding or overturning under the influence of centrifugal force. Stability is especially impaired by an increase in the position of the center of mass of the vehicle (for example, a large mass of cargo on a removable roof rack);

Longitudinal.

Its violation is manifested in the slipping of the driving wheels when overcoming prolonged icy or snow-covered ups and downs of the car. This is especially true for road trains.

CAR CONTROL

Handling is the ability of a car to move in the direction given by the driver.

One of the characteristics of handling is understeer - the ability of a car to change the direction of travel when the steering wheel is stationary. Depending on the change in the turning radius under the influence of lateral forces (centrifugal force when cornering, wind force, etc.), steering can be:

Insufficient - the car increases the turning radius;

Neutral - the turning radius does not change;

Excessive - the turning radius is reduced.

Distinguish between tire and roll steering.

Tire steering

Tire understeer is related to the property of tires to move at an angle to a given direction during lateral pull (displacement of the contact patch with the road relative to the plane of rotation of the wheel). If tires of a different model are fitted, steering may change and the vehicle will behave differently when cornering at high speeds. In addition, the amount of lateral slip depends on the tire pressure, which must correspond to that specified in the vehicle's operating instructions.

Heel steering

Heel steering is associated with 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 tilt towards the roll sides, increasing the slip.

INFORMATIVITY

Informativeness - the property of a car to provide the driver and other road users with the necessary information. Insufficient information from other vehicles on the road about the condition of the road surface, etc. often causes an accident. Internal provides the ability for the driver to perceive the information necessary to drive the vehicle.

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 ineffective washers, windshield blowing and heating systems, windshield wipers, and the absence of standard rear-view mirrors drastically impair visibility under certain road conditions.

The location of the instrument panel, buttons and control keys, gear lever, etc. should provide the driver with a minimum time to monitor readings, operating switches, etc.

External information content - providing other traffic participants with information from the car, which is necessary for the correct interaction with them. It includes an external light alarm system, a sound signal, dimensions, shape and color of the body. The informative value of cars depends on the contrast of their color relative to the road surface. According to statistics, cars painted in black, green, gray and blue are twice as likely to get into accidents due to the difficulty of distinguishing them in poor visibility conditions and at night. Defective direction indicators, brake lights, side lights will not allow other road users to recognize the driver's intentions in time and make the right decision.

COMFORTABLE

The comfort of the car determines the time during which the driver is able to drive the car without fatigue. The increase in comfort is facilitated by the use of automatic transmission, speed controllers (cruise control), etc. Currently, cars are produced with adaptive cruise control. It not only automatically maintains the speed at a given level, but also, if necessary, reduces it to a complete stop of the car.

3 Passive vehicle safety

BODY

It provides acceptable loads on the human body from a sharp deceleration in an accident and preserves the space of the passenger compartment after body deformation.

In a severe accident, there is a danger that the engine and other components may enter the driver's cab. Therefore, the cabin is surrounded by a special "safety cage", which is an absolute protection in such cases. The same ribs and bracing can be found in the doors of the car (in case of side collisions). This also includes the areas of energy extinguishing.

In a severe accident, a sudden and sudden deceleration occurs until the vehicle comes to a complete stop. This process causes huge overloads on the bodies of passengers, which can be fatal. From this it follows 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 accomplish this is to design collision dampening areas in the front and rear of the body. The destruction of the car will be more severe, but the passengers will remain intact (and this is in comparison with the old "thick-skinned" cars, when the car got off with a "slight fright", but the passengers were seriously injured).

The body structure provides that in a collision, the body parts are deformed as if separately. In addition, high-stress metal sheets are used in the construction. This makes the car more rigid, and on the other hand allows it to be less heavy.

SEAT BELTS

At first, cars were equipped with two-point belts that “held” the riders by the stomach or chest. Less than half a century later, engineers realized that the multi-point design is much better, because in an accident it allows you to distribute the belt pressure on the body surface 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 a person in the seat "tightly". But in "civilian" because of their simplicity and convenience, three-point have taken root.

In order for the belt to function properly, it must fit snugly to the body. Previously, belts had to be adjusted and adjusted to fit. With the advent of inertial belts, the need for "manual adjustment" has disappeared - in a normal state, the coil spins freely, and the belt can grab a passenger of any size, it does not constrain the action and every time the passenger wants to change the position of the body, the strap always fits snugly to the body. But at that moment, when "force majeure" comes, the inertial coil will immediately fix the belt. In addition, on modern machines, squibs are used in belts. Small charges of explosives detonate, the belt is tugged, and it presses the passenger against the back of the seat, preventing him from hitting.

Seat belts are one of the most effective means of protection in an accident.

Therefore, passenger cars must be fitted with seat belts if anchorage points are provided for this. The protective properties of belts largely depend on their technical condition... Belts malfunctions, in which the operation of the car is not allowed, 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 strap should be freely drawn into the reel and blocked when the vehicle 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.

AIR BAGS

One of the most common and effective safety systems in modern cars (after seat belts) is airbags. They began to be widely used already in the late 70s, but only a decade later they really took their rightful place in the safety systems of cars of most manufacturers.

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 doors, body pillars, etc.). Some car models have their forced shutdown due to the fact that people with heart problems and children may not withstand their false alarms.

Today, airbags are common, not only in expensive cars, but also in small (and relatively inexpensive) cars. Why are airbags needed? And what are they?

Airbags have been developed for both drivers and front-seat passengers. For the driver, the pillow is usually installed on the steering wheel, for the passenger - on dashboard (depending on the design).

The front airbags deploy when an alarm is received from the control unit. Depending on the design, the degree of gas filling of the pillow can 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.

The side airbags are designed to reduce damage to people in the vehicle in a side impact. They are installed on the doors or in the seat backs. In the event of 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 influence of airbags on the probability of driver death in frontal collisions have shown that this is reduced by 20-25%.

In the event that the airbags have deployed or have 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's volume is up to 130 liters. It is easy to imagine that when the system is triggered, the volume of the cabin decreases by 200-250 liters within 0.04 seconds (see figure), which puts a considerable load on the eardrums. In addition, an airbag flying out at a speed of more than 300 km / h is fraught with a considerable danger to people if they are not wearing a seat belt and nothing slows down the inertial movement of the body towards the airbag.

There are statistics on the impact of airbags on crash injuries. What should be done to reduce the likelihood of injury?

If your car has an airbag, you should not place a rearward facing child seat on the car seat where the airbag is located. When inflated, the airbag can move the seat and cause injury to the child.

Airbags in a passenger seat increase the likelihood of death for children under 13 sitting in that seat. A child below 150 cm in height can be hit in the head by an air cushion that opens at a speed of 322 km / h.

Headrests

The role of the headrest is to prevent sudden movement of the head during an accident. Therefore, the height of the head restraint and its position should be adjusted to the correct position. Modern head restraints have two degrees of adjustment to prevent injuries to the cervical vertebrae when moving "overlap", so characteristic of rear collisions.

Effective protection when using a head restraint can be achieved if it is exactly in line with the center of the head at the level of its center of gravity and no further than 7 cm from the back of the head. Please be aware that some seat options change the size and position of the headrest.

INJURY STEERING MECHANISM

Trauma-safe steering is one of the design measures that ensure the passive safety of the car - the ability to reduce the severity of the consequences of road accidents. The steering gear can cause serious injury to the driver in a head-on collision with an obstacle by crushing the front of the vehicle with the entire steering gear moving towards the driver.

The driver can also get injured from the steering wheel or steering shaft when moving forward suddenly as a result of a frontal collision, when the movement is 300… 400 mm with a weak seat belt tension. To reduce the severity of injuries sustained by the driver in frontal collisions, which account for about 50% of all road traffic accidents, various designs of injury-free steering mechanisms are used. For this purpose, in addition to a steering wheel with a recessed hub and two spokes, which can significantly reduce the severity of injuries caused by 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 during head-on collisions with obstacles, cars and other vehicles.

Other energy-absorbing devices are also used in injury-safe steering systems for passenger cars, which connect composite steering shafts. 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 collapses and the connecting plates deform and reduce the movement of the steering shaft inside the passenger compartment.

The main elements of a wheel assembly are a rim with a disc and a pneumatic tire, which can be tubeless or consist of a tire, tube and rim tape.

SPARE OUTPUTS

Roof hatches and bus windows can be used as emergency exits for quick evacuation of passengers from the passenger compartment in the event of an accident or fire. For this purpose, inside and outside the passenger compartment of buses, special means for opening emergency windows and hatches. So, glass can be installed in the window openings of the body on a two locking rubber profile with a locking cord. If a danger arises, it is necessary to pull out the lock cord using a clip attached to it and squeeze out the glass. Some windows are hinged in the opening and have handles to open them outward.

Devices for activating emergency exits of buses in operation must be in working order. However, during the operation of buses, employees of the ATP often remove the bracket on the emergency windows, fearing deliberate damage to the window seal by passengers or pedestrians in cases where this is not dictated by necessity. Such "foresight" makes it impossible to urgently evacuate people from buses.

4 Environmental safety of the car

Environmental Safety Is a property of a car that allows to reduce the harm caused to road users and the environment during its normal operation. Measures to reduce the harmful effects of vehicles on the environment should be considered reducing the toxicity of exhaust gases and noise levels.

The main pollutants in the operation of vehicles are:

- traffic fumes;

- oil products during their evaporation;

- tire abrasion products, brake pad and clutch discs, asphalt and concrete surfaces.

The main measures to prevent and reduce the harmful effects of cars on the environment should be considered:

1) development of such vehicle designs that would less pollute the atmospheric air with toxic components of exhaust gases and create a lower noise level;

2) improvement of methods of repair, maintenance and operation of cars in order to reduce the concentration of toxic components in exhaust gases, the level of noise produced by cars, and environmental pollution with operating materials;

3) compliance with the design and construction of highways, engineering structures, service facilities such requirements as fitting the facility into the landscape; rational combination of elements of the plan and longitudinal profile, ensuring the constancy of the vehicle speed; protection of surface and ground waters from pollution; combating water and wind erosion; prevention of landslides and landslides; conservation of flora and fauna; reduction of the area allocated for construction; protection of buildings and structures near the road from vibrations; fighting traffic noise and air pollution; application of construction methods and technologies that bring the least damage to the environment;

4) use of means and methods of organizing and regulating traffic, ensuring optimal modes of movement and characteristics traffic flows, reduction of stops at traffic lights, the number of gear changes and the time of engine operation in unsteady modes.

Car noise reduction techniques

To reduce the noise of the car, first of all, they tend to design less noisy mechanical units; reduce the number of processes accompanied by impacts; to reduce the amount of unbalanced forces, the speed of flow around parts with gas jets, the tolerances of mating parts; improve lubrication; use plain bearings and noiseless materials. In addition, the reduction of vehicle noise is achieved by the use of noise-absorbing and noise-insulating devices.

Engine intake noise can be reduced using a specially designed air cleaner with a resonance and expansion chambers, and the design of the intake pipes, which reduce the speed of the air-fuel mixture flowing around the inner surfaces. These devices reduce the intake noise level by 10-15 dB A-weighted.

Noise level when exhaust gases are released (when they flow through the exhaust valves) can reach 120–130 dB on the A scale. To reduce exhaust noise, install active or reactive silencers. The most common simple and cheap active mufflers are multi-chamber channels, the inner walls of which are made of sound-absorbing materials. The sound is extinguished by the friction of the exhaust gases against the inner walls. The longer the length of the muffler and the smaller the cross-section of the channels, the more the sound is damped.

Jet mufflers are a combination of elements of different acoustic elasticity; noise reduction in them occurs due to multiple reflection of sound and its return to the source. It should be remembered that the more efficiently the muffler works, the more the effective engine power decreases. These losses can reach 15% or more. During the operation of cars, it is necessary to carefully monitor the serviceability (first of all, the tightness) of the intake and exhaust tracts. Even a slight depressurization of the muffler sharply increases the exhaust noise. Noise in the transmission, chassis and bodywork of a new, serviceable vehicle can be reduced by design improvements. The gearbox uses synchronizers, constant-mesh helical gears, locking tapered rings and a number of other design solutions. Intermediate driveshaft supports, hypoid main gears, and less noisy bearings are gaining popularity. Suspension elements are being improved. Welding, soundproofing pads and coatings are widely used in the structures of bodies and cabs. Noise in the above parts and mechanisms of cars can arise and reach significant values \u200b\u200bonly in case of malfunctions of individual units and parts: breakage of gear teeth, warpage of clutch discs, imbalance of the propeller shaft, violation of clearances between gear wheels in the main gear, etc. The noise of the car increases especially sharply in case of malfunction of various elements of the body. The main way to eliminate noise is to properly maintain the vehicle.

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 experts in many countries pay great attention to the so-called passive safety of the car, which makes it possible to reduce the severity of the consequences of an accident.

LITERATURE

1.www.anytyres.ru

2.www.transserver.ru

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. manual for students of higher education. institutions / A.E. Gorev, E.M. Oleshchenko. - M .: Publishing Center "Academy". 2006. (pp. 187-190)

Moscow State

Automobile and Road Institute

(Technical University)

CORPORATE FACULTY

ABSTRACT for the course

"Organization of road transport and traffic safety"

ON THE TOPIC OF

« Passive vehicle safety»

Completed by student V.L. Kharchenko.

Group 3 ZPS

Checked by Vladimir Mikhailovich Belyaev

MOSCOW 2009

Introduction

2. Seat belts

3. Airbags

4. Headrests

5.Crash-proof steering gear

6. Emergency exits

Conclusion

Literature

INTRODUCTION

A modern automobile is inherently a hazardous device. Taking into account the social significance of the car and its potential danger during operation, manufacturers equip their cars with tools that contribute to its safe operation. Of the complex of means with which a modern car is equipped, passive safety means are of great interest. Passive vehicle safety should ensure the survival and minimization of the number of injuries for the passengers of the vehicle involved in a road traffic accident.

In recent years, passive vehicle safety has become one of the most important elements from the point of view of manufacturers. Huge funds are invested in the study of this topic and its development due to the fact that firms care about the health of customers.

I will try to explain a few definitions hidden under the broad definition of "passive safety".

It is subdivided into external and internal.

Internal measures include measures to protect people sitting in the car by means of 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 is a set of units and devices that allow you to save the life of car passengers in an accident. Includes, but is not limited to:

1. airbags;

2. crushing or soft elements of the front panel;

3. a folding steering column;

4.trauma-safe pedal assembly - in a collision, the pedals are separated from the attachment points and reduce the risk of injury to the driver's legs;

5.inertial seat belts with pretensioners;

6.Energy absorbing elements of the front and rear parts of the car, crumpled upon impact - bumpers;

7. seat head restraints - protect the passenger's neck from serious injuries when the car is struck from behind;

8.safe glasses: tempered, which, when broken, crumble into many mild fragments and triplex;

9.Roadsters, reinforced A-pillars and upper windshield frame in roadsters and convertibles, crossbars in the doors.

1.BODY

It provides acceptable loads on the human body from a sharp deceleration in an accident and preserves the space of the passenger compartment after body deformation.

In a severe accident, there is a danger that the engine and other components can enter the driver's cab. Therefore, the cabin is surrounded by a special "safety cage", which is an absolute protection in such cases. The same ribs and stiffening bars can be found in the doors of the car (in case of side collisions). This also includes the areas of energy extinguishing.

2. SEAT BELTS

At first, cars were equipped with two-point belts that "held" the riders by the belly or chest. Less than half a century later, engineers realized that the multi-point design is much better, because in an accident it allows you to distribute the belt pressure on the body surface 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 a person in the seat "tightly". But in "civilian" because of their simplicity and convenience, three-point have taken root.

In order for the belt to function properly, it must fit snugly to the body. Previously, belts had to be adjusted and adjusted to fit. With the advent of inertial belts, the need for "manual adjustment" has disappeared - in a normal state, the coil spins freely, and the belt can grab a passenger of any size, it does not hinder the action and every time the passenger wants to change the position of the body, the strap always fits snugly to the body. But at that moment, when "force majeure" comes, the inertial coil will immediately fix the belt. In addition, on modern machines, squibs are used in belts. Small charges of explosives detonate, the belt is tugged, and it presses the passenger against the back of the seat, preventing him from hitting.

Seat belts are one of the most effective means of protection in an accident.

Therefore, passenger cars must be fitted with seat belts if anchorage points are provided for this. The protective properties of belts largely depend on their technical condition. Belts malfunctions, in which the car is not allowed to operate, include tears and abrasions of the fabric tape of the straps visible to the naked eye, unreliable fixation of the tongue of the webbing in the lock or the absence of automatic ejection of the tongue when the lock is unlocked. For inertial-type seat belts, the strap should be freely drawn into the reel and blocked when the car moves sharply at a speed of 15 - 20 km / h. Belts that have experienced critical loads during an accident in which the body of the car 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 only a decade later they really took their rightful place in the safety systems of cars of most manufacturers.

They are placed not only in front of the driver, but also in front of the front passenger, as well as on the sides (in doors, body pillars, etc.). Some car models have their forced shutdown due to the fact that people with heart problems and children may not withstand their false alarms.

Today, airbags are common not only on 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 front-seat passengers. For the driver, the airbag is usually installed on the steering wheel, for the passenger - on the dashboard (depending on the design).

Here is a diagram of how the airbag system works:

Studies of the influence of airbags on the probability of driver death in frontal collisions have shown that this is reduced by 20-25%.

In the event that the airbags have deployed or have been damaged in any way, they cannot be repaired. The entire airbag system must be replaced.

There are statistics on the impact of airbags on crash injuries. What should be done to reduce the likelihood of injury?

If your car has an airbag, you should not place a rearward facing child seat on the car seat where the airbag is located. When inflated, the airbag can move the seat and cause injury to the child.

4. HEADREST

5. INJURY STEERING MECHANISM

The main elements of a wheel assembly are a rim with a disc and a pneumatic tire, which can be tubeless or consist of a tire, tube and rim tape.

6. SPARE OUTPUTS

Roof hatches and bus windows can be used as emergency exits for quick evacuation of passengers from the passenger compartment in the event 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, glass can be installed in the window openings of the body on a two locking rubber profile with a locking cord. If a danger arises, it is necessary to pull out the lock cord using a clip attached to it and squeeze out the glass. Some windows are hinged in the opening and have handles to open them outward.

CONCLUSION

LITERATURE safety carExamination \u003e\u003e Transport

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Coursework \u003e\u003e Transport

... safety... Active safety car - property car prevent road accidents (reduce the likelihood of occurrence). Passive safety car - property car ...

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KOKSHETAU UNIVERSITY NAMED AFTER ABAY MYRZAKHMETOV

GRADUATE WORK

specialty 5В090100 - "ORGANIZATION OF TRANSPORTATION, MOVEMENT AND OPERATION OF TRANSPORTATION"

IMPROVING THE PASSIVE SAFETY OF THE CAR BY IMPROVING ITS DESIGN ELEMENTS

Alpysbaev Temirlan Mukhamedrashidovich

Kokshetau, 2016

Introduction

2.3.1 Seat belt

2.3.2 Body

2.3.3 Safety terminals

2.3.4 Airbags

2.3.5 Headrests

2.3.6 Seat belt tension limiters

2.3.7 Rack seat belt pretensioner

2.3.8 Crash-free steering gear

2.3.9 Emergency exits

2.4 Driver's seat

3. Environmental safety of the vehicle

4. Economic efficiency of passive safety equipment

4.1 Efficiency of ergonomics

4.2 Cost-effectiveness of vehicle modernization

Conclusion

List of used literature

Introduction

Relevance of the research topic. Vehicle safety includes a set of design and operational properties that reduce the likelihood of road accidents, the severity of their consequences and negative impact on the environment.

Road safety significantly depends on the design of the vehicle, on the ergonomics of the driver's workplace, which can affect the level of his fatigue and, in general, the state of health. As studies show, practically no attention is paid to this factor in the examination of road traffic accidents (RTA). When creating new vehicles, this problem is considered one of the most important, but so far the CIS countries and Kazakhstan, including, are lagging behind the leading foreign firms in this matter. But the assessment of the influence of ergonomic factors on the performance and health of the driver is not applied abroad either.

The aim of the thesis is to address the issue of increasing the passive safety of the car by improving the elements of its design.

To achieve this goal, the following tasks are being solved:

Analysis of parameters providing passive safety of a vehicle;

Finding ways to improve vehicle structural elements;

Consideration of the environmental safety of the vehicle;

Determination of the economic efficiency of passive safety equipment. passive safety motor vehicle construction

The object of research in the thesis is the passive safety of a vehicle.

The subject of the research is the structural elements of a car that affect the safety of passengers and a car during its movement and abrupt stop.

The degree of study of the problem: the basic principles of ensuring road safety and passive safety of a vehicle have long been widely known, which is reflected in the works of G.V. Spichkina, A.M. Tretyakov, B.L. Libina B.L., I.A. Vengerova, A.M. Kharazova and others.

Research methods: analytical processing of the results of publications and polls, analysis of statistical data according to reports of the departments of internal affairs and the Ministry of Transport and Communications, the method of automated search on the Internet.

The scientific novelty of the work lies in the fact that it is proposed to equip a vehicle with such structural elements that increase the safety of the vehicle, driver and passengers while driving and at the time of an abrupt stop.

The practical value of the thesis is in the development of components of the vehicle passive safety system, which is extremely important for the conditions of a collision and overturning of a vehicle at the time of an increase in the overall level of accidents on the road network of cities and on international highways.

The practical basis for writing the thesis was the REO UDP UDP, Akmola region, Kokshetau.

The structure and volume of the thesis: The work consists of more than sixty pages of the text of the explanatory note. Introduction, four parts, conclusion, bibliography and electronic presentation.

In the introduction, the relevance of the work is determined, the goal and objectives of the study are formulated, the scientific novelty and practical significance are reflected.

The first chapter analyzes the parameters that ensure the passive safety of the vehicle;

In the second chapter, the ways of improving the elements of the car structure are proposed;

The third chapter deals with the environmental safety of the vehicle;

The fourth chapter defines the economic efficiency of passive safety equipment.

In the conclusion, brief conclusions are made on the results of the work, an assessment of the completeness of solutions to the tasks posed is determined, recommendations and initial data on the specific use of the results of the work are given.

1. Analysis of the parameters providing passive safety of the vehicle

1.1 Vehicle safety

Vehicle safety includes a set of design and operational properties that reduce the likelihood of road accidents, the severity of their consequences and negative impact on the environment.

Distinguish between active, passive, post-accident and environmental safety of the vehicle. The active safety of a vehicle is understood as its properties that reduce the likelihood of a road traffic accident. Active safety is provided by several operational properties that allow the driver to confidently drive the car, accelerate and brake with the required intensity, and maneuver on the roadway, which is required by the road situation, without significant expenditure of physical forces. The main of these properties are: traction, braking, stability, controllability, cross-country ability, information content, habitability.

Passive safety of a vehicle is understood as its properties that reduce the severity of the consequences of a road traffic accident. Distinguish between external and internal passive vehicle safety. The main requirement of external passive safety is to ensure such a constructive implementation of the outer surfaces and elements of the vehicle, in which the probability of damage to a person by these elements in the event of a road traffic accident would be minimal.

As you know, a significant number of accidents are associated with collisions and collisions with a fixed obstacle. In this regard, one of the requirements for the external passive safety of vehicles is to protect drivers and passengers from injury, as well as the vehicle itself from damage by external structural elements.

An example of a passive safety element can be a trauma-safe bumper, the purpose of which is to soften the impact of the car on obstacles at low speeds (for example, when maneuvering in a parking area). The endurance limit of G-forces for a person is 50-60g (g is the acceleration of gravity). The endurance limit for an unprotected body is the amount of energy perceived directly by the body, corresponding to a movement speed of about 15 km / h. At 50 km / h, the energy exceeds the permissible by about 10 times. Therefore, the task is to reduce the acceleration of the human body in a collision due to prolonged deformations of the front of the car body, which would absorb as much energy as possible.

Note - 3

Figure 1. - Vehicle safety structure

That is, the greater the deformation of the car and the longer it occurs, the less overload the driver experiences when colliding with an obstacle. External passive safety is related to decorative elements of the body, handles, mirrors and other parts attached to the car body. Recessed door handles are increasingly used on modern cars, which do not cause injury to pedestrians in the event of a traffic accident. The protruding emblems of the manufacturers on the front of the vehicle are not used. There are two main requirements for the internal passive safety of the car:

Creation of conditions under which a person could safely withstand any overload;

Elimination of traumatic elements inside the body (cab).

The driver and passengers in a collision, after an instant stop of the car, still continue to move, maintaining the speed that the car had before the collision. It is at this time that most of the injuries occur as a result of hitting the head with windshield, chest about steering wheel and the steering column, with your knees on the lower edge of the instrument panel.

An analysis of road traffic accidents shows that the vast majority of those killed were in the front seat. Therefore, when developing passive safety measures, first of all, attention is paid to ensuring the safety of the driver and passenger in the front seat. The design and rigidity of the car body are made in such a way that the front and rear parts of the body are deformed during collisions, and the deformation of the passenger compartment (cabin) was as minimal as possible to preserve the life support zone, that is, the minimum required space, within which the body of a person inside the body is excluded from being squeezed ...

In addition, the following measures should be provided to reduce the severity of the consequences of a collision: - the need to move the steering wheel and steering column and absorb impact energy by them, as well as evenly distribute the impact over the surface of the driver's chest; - exclusion of the possibility of ejection or loss of passengers and the driver (reliability of door locks); - availability of personal protective and restraining equipment for all passengers and the driver (seat belts, head restraints, airbags); - absence of traumatic elements in front of passengers and driver; - equipment of the body with safety glasses. The effectiveness of using seat belts in combination with other measures is confirmed by statistical data. Thus, the use of belts reduces the number of injuries by 60 - 75% and reduces their severity.

One of effective ways The solution to the problem of limiting the movement of the driver and passengers in a collision is the use of pneumatic cushions, which, when the car collides with an obstacle, are filled with compressed gas in 0.03 - 0.04 s, take the impact of the driver and passengers and thereby reduce the severity of injury.

1.2 Biomechanics of the main types of road accidents

In the process of the most severe road accidents (collisions, collisions with fixed obstacles, overturning), the car body is first deformed, and the primary impact occurs. In this case, the kinetic energy of the car is spent on breakage and deformation of parts. The person inside the car continues to move by inertia at the same speed. The forces holding the human body (muscle forces of the limbs, friction against the seat surface) are small compared to inertial loads and cannot impede movement. 8

When a person comes into contact with parts of the car - the steering wheel, dashboard, windshield, etc., a secondary impact occurs. The parameters of the secondary impact depend on the speed and deceleration of the car, the movement of the human body, the shape and mechanical properties of the parts against which it hits. At high vehicle speeds, a tertiary impact is also possible, i.e. impact of internal organs of a person (for example, brain mass, liver, heart) on solid parts of the skeleton.

In 1994, the great Formula 1 pilot, Ayrton Senna, crashed in Imola. While in the rugged monocoque, he did not receive life-threatening "external" injuries, but died from multiple injuries to internal organs and the brain caused by overload. The monocoque remained practically intact, the pilot was killed by an almost instant deceleration from a speed of 300 km / h to zero. At the speeds common on our roads, most of the injuries to drivers and passengers are from a secondary impact.

Of greatest importance for internal passive safety are collisions of vehicles and their collisions with a fixed obstacle, and for external - collisions with pedestrians.

According to statistics, the most dangerous seat in the car is the right front seat, because instinctively, at the very last moment, the driver still deflects the blow from himself, and the most serious injuries are received by the passenger who did not use the seat belt. In second place is the driver's. On the third - rear right. And most safe place - behind, behind the driver. 3

In fig. 2 shows the mechanism of injury formation in oncoming collisions in a passenger car driver. At the beginning of the impact, the driver slides forward on the seat, and his knees hit the instrument panel (Fig. 2, a and b). Then the hip joints are bent, and the upper body bends forward until it hits the steering wheel (c and d). At high vehicle speeds, a blow to the windshield (e and f) is possible, and in side collisions - head damage to the corner side of the body. The front passenger, moving forward, also hits first with his knees on the instrument panel, then his head on the windshield (Fig. 3, a-d). If the car is moving at high speed, the chin and chest of the passenger may be injured on the upper edge of the instrument panel (Fig. 3, e and f). Side impacts injure shoulders, arms and knees. Thus, the most common sources of driver injury are the steering column, steering wheel, and instrument panel. For front passengers, the dashboard and windshield are dangerous, and for rear passengers, the backrests of the front seats. Buttons and control levers, ashtrays, and radio components usually do not cause serious injury. However, if the driver and passengers are hit with the head on them, the face may be injured. Door parts are also sources of damage. A large number of injuries are suffered by people when thrown through doors that have opened as a result of an impact.

Note 3

Figure 2. - The mechanism of formation of injuries in a driver in a collision of cars

Note - 3

Figure 3. - The mechanism of formation of injuries in the front passenger

In addition, you must consider the following points:

The engine, which is located in front of most modern cars, as a result of an impact, may well be inside the cabin and fall to its feet;

If the car is “caught up” from behind, then a sharp throwing back of the head is a sure fracture of the spine;

Individual parts of the interior can, upon impact, break loose from their seats and go on a journey through the cabin.

When the car hits an obstacle, the person continues to move inside the stopped car by inertia. But not long - to the nearest solid object, which are enough in the cabin.

Imagine a car crashing into a concrete wall at 72 km / h (20 m / s). In this case, the overload acting on the passengers will be 25.5g, that is, a person weighing 75 kg will “put” on the dashboard with a force of 1912 kg! It is useless to rest your hands and feet. By the way, a similar calculation shows why durable jeeps are more dangerous for passengers. In such conditions, a powerful frame structure will collapse by only 0.3-0.4 m. Accordingly, the overloads and forces acting on passengers will double with all the ensuing consequences.

1.3 Components of the vehicle passive safety system

The modern car is a source of increased danger. The steady increase in the power and speed of the car, the density of traffic flows significantly increase the likelihood of an emergency.

To protect passengers in an accident, technical safety devices are being actively developed and implemented. At the end of the 50s of the last century, seat belts appeared, designed to keep passengers in place in a collision. In the early 1980s, airbags were applied.

The set of structural elements used to protect passengers from injury in an accident makes up the vehicle's passive safety system. The system should provide protection not only for passengers and a specific vehicle, but also for other road users. 8

The most important components of the vehicle passive safety system are:

seat belts;

active head restraints;

airbags;

safe body structure;

emergency battery disconnector;

a number of other devices (rollover protection system on a convertible;

child safety systems - mountings, armchairs, seat belts).

A modern development is the pedestrian protection system. The emergency call system takes a special place in the passive safety of the car.

The modern system of passive vehicle safety is electronically controlled, which ensures efficient interaction of most of the components. Structurally, the control system includes input sensors, a control unit and actuators.

Input sensors record the parameters at which an emergency occurs and convert them into electrical signals. These include crash sensors, seat belt buckle switches, front passenger seat occupied sensor, and driver and front passenger seat position sensors.

As a rule, two shock sensors are installed on each side of the car. They ensure the operation of the appropriate airbags. At the rear, shock sensors are used when equipping the vehicle with electrically powered active head restraints.

The seat belt switch locks in the seat belt. The seat occupancy sensor of the front passenger allows in the event of an emergency and the absence of a passenger in the front seat to keep the corresponding airbag.

Depending on the position of the driver's and front passenger's seats, which is recorded by the corresponding sensors, the order and intensity of use of the system components change. 8

Based on the comparison of the sensor signals with the control parameters, the control unit recognizes the occurrence of an emergency situation and activates the necessary actuators of the system elements.

The actuators of the elements of the passive safety system are squibs of airbags, seat belt pretensioners, an emergency battery disconnect switch, an active head restraint drive mechanism (when using electrically operated head restraints), as well as a warning lamp indicating that the seat belts are not fastened.

Actuators are activated in a specific combination in accordance with the installed software. fifteen

In the event of a frontal impact, depending on the severity, the seat belt pretensioners or the front airbags and seat belt pretensioners can be deployed.

With a frontal-diagonal impact, depending on its force and the angle of collision, the following may work:

seat belt tensioners;

front airbags and seat belt tensioners;

relevant (right or left) side airbags and seat belt pretensioners:

appropriate side airbags, head airbags and belt pretensioners;

front airbags, corresponding side airbags, head airbags and belt pretensioners.

In a side impact, depending on the force of the impact, the following may be triggered:

appropriate side airbags and belt tensioners;

appropriate head airbags and seat belt tensioners;

the corresponding side airbags, head airbags and seat belt pretensioners.

In the event of a rear impact, the seat belt pretensioners, battery disconnect switch and active head restraints can be triggered depending on the severity of the impact.

2. Ways to improve vehicle design elements

2.1 Ergonomic assessment of vehicles

Traffic safety significantly depends on the ergonomics of the driver's workplace, which can affect the level of his fatigue and, in general, the state of health. Unfortunately, practically no attention is paid to this factor when carrying out expert examinations of road accidents, although sometimes they talk about it. When creating new vehicles, this problem is getting more and more attention. But abroad, the assessment of the influence of ergonomic factors on the performance and health of the driver is not applied. Also, no attention is paid to psychological aspects in driving schools, while directly or indirectly they are often the causes of road accidents. The psychological culture of driving school teachers facilitates the development of knowledge and increases the efficiency of their use in driving practice. 28

Modern vehicles, in addition to numerous characteristics that are often detailed by manufacturers in passports and other technical documents, also have numerous ergonomic characteristics that characterize the comfort and safety of the driver and passengers. These include noise, vibration, gas pollution, dust, the shape of the seats, the design of the instrument panel, etc.

However, these parameters are usually not reflected in the technical documentation. In accordance with the current regulatory documents, each of the ergonomic parameters of vehicles is generally assessed individually, independently of the others, despite the fact that the ergonomic parameters always affect the human body cumulatively. The overall assessment of the workplace is determined in points, the calculation method of which is very subjective and not justified metrologically.

For a comprehensive ergonomic quantitative assessment of vehicles, the "Locus" company together with the St. Petersburg medical academy them. I. I. Mechnikov carried out preliminary studies aimed at determining the possibility of using for this purpose the ergonomic parameter "Ergo capacity", measured in new units of D, quantitatively characterizing the biological costs of the human body under the complex effects of various loads.

Ergonomic assessment of vehicles by the parameter ergo intensity should be carried out under standard conditions on the corresponding vehicles, and include a set of medical studies of the body of drivers and mathematical analysis results using a special computer program.

However, such studies require a fairly large amount of work and significant funding.

Therefore, at this stage, we performed only preliminary studies, mainly using the results of previous work.

Determination of the magnitude of the ergo capacity is based on the criterion of the recovery time of functional shifts that occur in the body as a result of labor activity - in this case, driving.

The materials at our disposal made it possible to calculate the energy consumption of various types of urban public transport: buses, trolleybuses, trams and passenger taxis.

As studies have shown, the pattern of development of functional changes in drivers and their recovery generally corresponds to similar processes in other types of human labor activity.

As it turned out, the functional shifts that occur in drivers are not fully restored during rest during the day, and their accumulation occurs. Full recovery takes place only on weekends. 3

Thus, the busy schedule of drivers leads to an accumulation of fatigue during the working week, which increases the likelihood of accidents.

After analyzing the results of numerous hygienic studies by various authors with the help of a specialized computer program, it was found that to ensure optimal working conditions, the value of the energy capacity should not exceed 8 D for 95% of people, since during the rest during the day there will be a complete restoration of functional shifts.

As preliminary studies have shown, the assessment of the ergonomic qualities of road transport in terms of ergo intensity will significantly improve the consumer qualities and safety of cars without investing any significant funds.

This is confirmed by the results of studies of the workplaces of air traffic controllers, as a result of which, through their minor modernization, the degree of fatigue of air traffic controllers has decreased by up to 3 times; computer workstations, as a result of which new computer tables have been developed, fully taking into account the specifics of work and individual requirements of operators, a number of other workstations and industrial equipment.

With regard to road transport, we already have some proposals for improving the ergonomic parameters of instrument panels, seat design, radio equipment and other components.

Thus, the introduction of ergonomic indicators into the list of technical parameters of road transport, in particular, ergonomics, will significantly improve the consumer qualities of vehicles and increase their safety.

When training drivers in driving schools, it would be useful to introduce some questions of psychology and ergonomics. The latter is decided by constructors and designers, but the driver can and must adjust his seat, taking into account his anthropometric data and psychological characteristics, so that there is maximum comfort for the driver's seat and less fatigue.

Knowing oneself is one of the most important aspects of setting up any education, but unfortunately in traditional education of any level this issue is lost, even where psychology is the leading academic discipline. Psychological academic disciplines are highly formalized. There is too little time in a driving school to study psychological disciplines, but when teaching other sections and even traffic rules, they can be set so that the student can feel this knowledge and pass through himself and realize it, and not just formally memorize for passing the exam. But, perhaps, it is necessary to highlight the most important issues of psychology and ergonomics in relation to the peculiarities of road traffic.

The professional suitability of a driver is determined by basic characteristics such as temperament and character. Sanguine and phlegmatic drivers respond appropriately to traffic situation, while choleric and melancholic people with the wrong reaction can cause an accident or get into it. But people of all temperaments want to drive. Choleric and melancholic people should be aware of their characteristics, but at the same time they should also know that they can include traits of a sanguine or phlegmatic person, because every person has the properties of temperaments of all kinds. In addition, it is necessary to understand the essence of road behavior, as well as the impact of stress on the behavior of driving and on health.

It is obvious that the passive safety of the car during its operation directly depends on the psychological state of the driver. The presence of structural elements in a vehicle that help to level out the psychological background reduces the risk of serious injury to passengers.

2.2 Anthropometry and passive vehicle safety

Anthropometric data are the source material for the design and development of many technical systemswith whom a person has contact in his production and non-production activities. Until recently, anthropometric data has been used primarily to meet ergonomic requirements in automobile design. Research in the field of passive safety has shown that the use of anthropometric data is a prerequisite for the creation of safe vehicle structures. The use of anthropometric data has its own characteristics, due to which medical anthropometric data are often insufficient or even inapplicable.

When getting into a car, a person (driver or passenger) takes a specific position, which is determined by the interior of the car and the possibilities of adjusting the seat or controls. In addition, there are specific positions of parts of the human body, characteristic of certain conditions, in which a person may find themselves in a car. For example, when a car collides, the person in it assumes a position that is characteristic only for these conditions. The anthropometric measurements of car drivers by Stoudt and McFarland are typical examples of this kind of research. A feature of their technique is the use of a special rigid bench seat on which the measurements were taken, which excludes the influence of the structure and rigidity of the seat on the results obtained and allows the measurement results to be applied to any soft car seat.

The data obtained from anthropometric measurements characterize only the size of the human body and do not take into account the deviations that are caused by the person's clothing. Anthropometric measurements for passive safety purposes should be carried out taking into account the conditions typical for the position of a person in a car, and also include the clothes and shoes of the measured subjects. 28

Anthropometry refers to the measurement of a person. Many researchers have come to the conclusion that there is no average person, who often figured earlier as a criterion for constructive limitations of the sphere of human action. We can only talk about the maximum size of a person, obtained by measuring a certain population of the population and applicable to the system with which these people interact. A distinction is made between static and dynamic (or functional) measurements. Static measurements are carried out with a motionless, fixed in a certain position of the human body and can be used to ensure the adaptability of a person to the conditions of the interior of a car, i.e., its placement in a certain space. Dynamic measurements establish the limits that are necessary for a person to perform a control function.

The applicability of anthropometric data is characterized by the so-called representativeness. Representativeness is the extent to which a given size covers a particular population of people. Quantitatively, representativeness is a part of the area (in percent) under the curve of the normal distribution of the values \u200b\u200bof any anthropometric attribute (size) for a certain contingent of people with a continuous selection of individuals. Knowing the law of probability distribution, the average value of the trait (t) and the standard deviation (b), it is possible to determine the number of people in whom the value of the anthropometric trait fits into one or another interval. Using these data, it is possible in each specific case to calculate the number of people whose size this design will satisfy. As a rule, at present, when designing technical systems "man-machine", it is impossible to achieve full compliance of the machine with the requirements of all people, from the largest to the smallest. Usually not included in the 5% of the tallest or highest low people, depending on what the given size affects. In the automotive industry, with equal probability for the largest and the smallest people, their sizes are not taken into account. This can be illustrated by the following examples. When choosing the height of the car, you can limit yourself to the size corresponding to the smallest height of the 5% of the tallest people. On the contrary, by locating the controls, one can neglect the fact that some of them will be out of reach for the 5% of the lowest people. Thus, in each case, appropriate conditions will be provided for 95% of people. If we consider the interior of the car as a whole, then 90% of people will have sufficient comfort and only 5% of the tallest and 5% of the lowest people will experience some inconvenience. Experience shows that such a compromise is fully justified and economically feasible. 29

In the study of passive safety, a person is one of the main objects of study. However, the test conditions should simulate the accident conditions in the event of an accident that pose a danger to humans. Therefore, the question inevitably arises about the use of human body models - anthropometric mannequins. The creation of mannequins that most closely imitate the human body in terms of its physical and mechanical properties is impossible without knowledge of the anthropometric characteristics of a person. Representativeness of mannequins is also characterized by representativeness. Various foreign firms produce anthropometric mannequins for men and women of 5%, 50%, 90% and 95% representativeness, as well as mannequins for children of a certain age. In addition, a standard 3D or landing dummy design has been developed, the main dimensions of which can be adjusted from 5 to 95% representativeness. The creation of anthropometric mannequins does not mean, however, that there is a universal model that can completely replace a person. First, when creating a dummy, one has to make compromise decisions, since at the present level of science and technology, it is still not possible to achieve complete identity of the dummy design with the structure of the human body. Therefore, the created mannequins must be specially investigated to determine their characteristics and conformity of these characteristics to the characteristics of the human body. Secondly, the anthropometric characteristics of the population change over time.

Anthropometric dimensions are the most important part of the so-called living space in the passenger compartment. Living space is the minimum volume of the passenger compartment that must be provided in the event of an accident in order to prevent injury to people in the car. In the event of a collision, a small person may find themselves in more difficult conditions. The fact is that due to the possibility of longitudinal adjustment of the seat, a small person can move (for ease of control) forward so that his chest, for example, is closer to the interior elements than the chest of a large person. During a collision, due to elastic or plastic deformations, interior elements can reach the chest and cause injury to a person. It can also adversely affect the effectiveness of seat belts or other restraint systems. Restraint systems must be designed to provide adequate protection for drivers and passengers.

Mathematical modeling, widely used in passive safety studies, is also based on anthropometric data. In addition to dimensional characteristics, in order to create mathematical models of the human body, it is also necessary to have data on inertial properties, positions of the centers of gravity and articulation (mobility) of parts of the human body. With the help of mathematical models, by changing the input characteristics (dimensions, weight, etc.), it is possible to study in the most detail such a complex process as the movement of a person inside a car during an accident. A brief review of the use of anthropometric data for passive safety purposes makes it possible to judge the importance and necessity of special anthropometric studies in solving the problem of improving the safety of road transport. ...

From the first days of its existence, cars presented a certain danger to both those around and the people in them. The imperfection of the engine design led to explosions, and the sluggishness of those around - to the death of people. Currently, there are almost 1 billion vehicles in the world of various types, brands and modifications. The car has found the most widespread use as a vehicle used to transport goods and people. The speed of movement has sharply increased, the appearance of the car has changed, various safety elements are widely used. At the same time, the intensive development of motorization is accompanied by a number of regressive impacts on society: tons exhaust gases pollute the atmosphere, and road accidents cause enormous moral and material damage to society. In short, global motorization has both positive and negative consequences.

When developing new structural elements of a car, it is necessary to take into account how dangerous this or that element is for humans. Research conducted by the Cornell Aeronautics Laboratory under the American Traffic Injury Research Program has shown that the main cause of serious and fatal injuries is from impacts to the front guard and steering column. In second place are blows to windshields, which account for 11.3% of severe injuries and deaths. In addition, windshield is the cause of 21% of injuries (puncture of the skull, concussion, etc.).

In an accident, the driver most often hits the car with his head (13%), and the front passenger - with his feet (11.3%). Those wearing seat belts were seriously injured only in 7% of cases and light injuries in 34% of cases. When using more efficient safety belts with an inertia device, as a result of road accidents, only 5% of victims received serious injuries and 29% light injuries, while when using conventional belts with three-point anchorage, respectively 8 and 37%, and when using diagonal belts - 7 and 41 %.

Of interest are the data obtained by American scientists D.F.Hewelk and P.W. Jikas from the University of Michigan. They investigated 104 car accidents that killed 136 people. As a result, conclusions were drawn: there are four main causes of death of passengers (ejection from the seat, impacts on the steering, on the door and on the instrument panel); about 50% of victims could have been saved if passengers and drivers were fastened with seat belts; a further reduction in the number of accidents can be obtained by changing the design of the car - by installing devices that reduce the force of impact in a collision. 3

Of the 136 injured, 38 people were thrown out of the car. If they were fastened with seat belts, then 18 out of 28 thrown drivers and 6 out of 10 passengers in the front seat would be saved. Of the 24 drivers who sustained fatal steering injuries, 18 were killed by striking the steering wheel and spokes. Moreover, 16 drivers would not have been able to escape even with seat belts. The steering column and steering wheel were so extended into the driver's area that the chances of escape were minimized. In 19 cases, a blow to the body door was fatal for drivers and passengers. Again, the safety belt could provide only minimal protection, since only two passengers in the front seat could be saved using the appropriate harness. The dashboard was the cause of death in 15 cases (5 drivers and 10 passengers front seat). Most of them could have escaped using their seat belts. Structural elements such as the ceiling, car frame and some others have caused fatal injuries in 20 cases.

More than half of the deaths were caused by car drivers and a quarter by front seat passengers. Studies have found that the vast majority of those killed - 120 out of 136 people - were in the front seat during the accident. Therefore, the main focus should be on ensuring the safety of the driver and front passenger. In addition, the analysis showed that about 50% of the victims would have died even with the safety harness. Therefore, much attention should be paid to changing the arrangement of the cabin and the design of some parts in order to eliminate sharp cutting edges, as well as rigid elements that cause injury to drivers and passengers.

It is very important to establish which elements of the vehicle's internal equipment cause injury. A study of the statistical data of Italian, American and German researchers makes it possible to identify the structural elements of the car's interior, which most often injure a person. The first three places in terms of danger were taken: steering column, instrument panel, windshield. They are followed by: doors, rearview mirror. Physiologically, people are so diverse that when establishing the level of endurance for the weakest subject, the requirements for the construction will be practically impossible. At present, the design of protective devices in a car should, first of all, prevent a person from getting serious and serious injuries, while neglecting an increase in the (relative) number of minor injuries.

The fact that a rigid steering column is a danger to the driver became clear from the very first crash analyzes. Since the 1960s, attempts have been made to mitigate this risk through various design measures. Today, for example, the steering columns are equipped with a pivot that is released in the event of a collision. The most advanced steering columns are capable of absorbing impact energy. Of particular interest was the procon-ten system, which in a head-on collision moved the steering column and steering wheel forward away from the driver.

Note - 41

Figure 4. - Distribution of injured in road accidents

With the introduction of airbags, the task of the steering column has become more complex: it must now complement the protective potential of the belts and airbags. Telescopic rods and additional hinges serve to kinematically separate the steering wheel and the deforming bulkhead of the engine compartment. Therefore, upon impact up to a certain force, the steering wheel and the airbag maintain a certain living space in front of the seated person. The integrated sliding mechanism with damping function reduces, to the extent of technical capabilities, the loads that the chest and head are subjected to during impact. These elements are a good addition to the force limiters of the seat belt.

2.3 Components of the vehicle passive safety system

To ensure the safety of both passengers and other road users, the car must be equipped with a number of systems. The most important components of the passive safety system of modern cars are:

pretensioner seat belt system including child restraint system

active head restraints

airbag system (front, side, knee and head (curtain)

a crumple-resistant body with a roof of adequate strength and crumple zones in the front, rear and sides of the vehicle (they protect passengers by absorbing collision energy in a targeted manner)

rollover protection system on convertible

emergency battery switch.

Passive safety system components:

1 - emergency battery switch; 2 - safe self-opening hood in a collision; 3 - front passenger airbag; 4 - side airbag for the front passenger; 5 - front passenger side airbag; 6 - active head restraints; 7 - rear right airbag; 8 - left head airbag; 9 - left rear airbag; 10 - rear airbag crash sensor from the driver's side; 11 - seat belt tensioner; 12 - driver's side airbag; 13 - driver's side airbag impact sensor; 14 - driver's airbag; 15 - knee airbag; 16 - airbag control unit; 17 - crash sensor of the driver's frontal airbag; 18 - bonnet squib actuation sensor; 19 - crash sensor of the front passenger airbag

Note - 5

Figure 5. - Components of the passive safety system

2.3.1 Seat belt

A seat belt is a device consisting of straps, a locking device and anchorage parts that can be attached to the interior of the vehicle body or the seat frame and is designed to reduce the risk of injury to the user in the event of a collision or sudden braking by limiting movement his body.

Note - 5

Figure 6. - Seat belt

Currently, the most common belt is with a three-point fastening, which is a combination of a waist and diagonal belts. In this case, a belt is considered a belt that covers the user's body at the height of the pelvis, and a diagonal belt covers the chest diagonally from the thigh to the opposite shoulder.

On some types of vehicles, a harness type belt is used, which consists of a lap belt and shoulder straps.

The main elements of the seat belt are the buckle, the strap, the strap length adjuster, the strap height adjuster, the retractor and the locking mechanism.

Buckle - a device that allows you to quickly unfasten the belt and makes it possible to hold the user's body with the belt.

The strap is a flexible part of the belt designed to hold the user's body and transfer the load to the stationary fasteners.

The strap length adjuster may be part of the buckle, or a retractor may function. 3

The height adjustment device of the belt allows the position of the upper grip of the belt to be adjusted in height as desired by the user and, depending on the position of the seat, can be considered part of the belt or part of the belt anchor.

The seat belt may have a retractor. A retractor is a device for partially or completely retracting a seat belt. There are several types of retractors:

a retractor from which the webbing is fully pulled out with little force and which does not have an adjuster for the length of the extended webbing

an automatic retractor that allows you to obtain the desired strap length and, when the buckle is closed, automatically adjusts the strap length for the user. This device has an emergency locking mechanism. The locking mechanism can have a single or multiple sensitivity, i.e. triggered by braking or sudden belt movement

automatic retractor with pre-tensioning mechanism. The belt may have a pre-tensioning mechanism that forces the belt strap against the seat to tension the belt at the time of impact.

2.3.2 Body

The initial goal of the designers is to design such a car so that its external shape helps to minimize the consequences of the main types of road accidents (collisions, collisions, and damage to the vehicle itself).

The most severe injuries are pedestrians who run into the front of the vehicle. The consequences of a collision involving a passenger car can only be mitigated by constructive measures, including, for example, the following:

retractable headlights

flush-mounted wipers

flush-mounted gutters

recessed door handles

The determining factors for ensuring the safety of passengers are:

deformation characteristics of the car body

length of the passenger compartment, the amount of survival space during and after a collision

restraint systems

areas of possible collision

steering system

fetching users

fire protection

In order to protect against impacts on passenger cars, there are three different areas that must be taken over in the event of an accident. The upper, middle and lower surfaces that receive impact are the roof, side and floor of the vehicle, respectively.

Note - 5

Figure 5. - Distribution of forces upon impact:

a - side impact; b - frontal impact

The aim of all impact protection measures is to minimize deformation of the body, and therefore, to minimize the risk of injury to passengers on impact. This is due to the fact that the forces arising from the impact act specifically on a specific component of the body structure. Thus, the coefficient of deformation of the parts to be hit is reduced, because the forces arising from this are distributed over a larger area.

The design of many other elements of the power structure in our time is determined in such a way as to ensure the ultimate rigidity and dissipation of impact energy in the largest possible number of directions (Fig. 6). Much attention is paid to doorways: here it is important to avoid jamming the doors.

The greatest problem for developers of passive safety systems is a side impact. The reserve of the crumple zone in a side collision, in contrast to the front or rear of the car, is an insignificant value of only 100… 200 mm. The Forezia developers have developed a mechanism to prevent the consequences of a side impact. The mechanism starts working 0.2 s before the collision according to the code of special sensors. At the command of the controller, after 60 ms, the rod 2 made of Shape Memory Alloy, which is installed under the seats across the body of the car, is extended, pushing the steel pin almost to the door. At the same time, the mechanism inside the door is triggered, turning the stop 3 into the working position. Now, in a side impact, the door will not be able to squeeze into the body. This mechanism reduces the deformation of the door to the inside of the body by 70 mm.

Note - 5

Figure 6. - Dissipation of impact energy

The operation of the mechanism is reversible, because there are no disposable squibs in it. If no accident occurs, the bar will be shortened to its original length and the spring will pull the pin back.

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