EP1311423A1

EP1311423A1 - Vehicle arrangement comprising deformation beams, and a method for control of deformation

Info

Publication number: EP1311423A1
Application number: EP01934714A
Authority: EP
Inventors: Björn FRENELL
Original assignee: Elaion Produkter
Current assignee: Elaion Produkter
Priority date: 2000-05-05
Filing date: 2001-05-04
Publication date: 2003-05-21
Also published as: SE0001652L; AU2001260870A1; SE522302C2; SE0001652D0; WO2001085527A1

Abstract

A vehicle arrangement comprising an active deformation beam for a vehicle, especially for the frontal structure of passenger cars and commercial vehicles, which beam during the entire collision course is able to adjust and change the energy absorption for different collision situations. At least two sensor devices, arranged along each deformation beam at known positions in relation to each other, are transmitting signals during the entire collision course to a control device, which calculates the collision location, the deformation speed, the change in deformation speed and available length of deformation zones. The control device can, when necessary, release organs for change of stiffness, arranged on the beams, such as gas generators or explosive charges. The beams are provided with folds, which make the beams changeable in shape and stiffness in several steps and can be effected by more than one organ for change of stiffness. The rigidity of the deformation zones can therefore be adjusted at different collision situations to be advantageous for the collision situation dependent on the collision speed, the weight of the vehicles, the collision location, more or less offset collision and oblique frontal collision. The invention relates furthermore to a method for adjusting the energy absorption of a vehicle to current collision situation.

Description

Vehicle arrangement coprising deformation beams, and a method for control of deformatio .

Technical area

The present invention concerns an arrangement and a method to adapt the energy absorption of the deformation zone of a vehicle for different types of collision situations.

Background

A major problem associated with collision safety and deformation zones constructed on a vehicle is that the collisions vary considerably with respect to speed, the weight of the vehicle, and the collision location. It is desirable that a vehicle, such as a passenger car, should cope with all collision situations and with all collision speeds, but this is impossible to achieve in practice. Passenger car manufacturers all over the world construct compromise solutions all the time.- Most cars, therefore, are constructed such that they pass collision tests and real collisions in a manner that is relatively satisfactory for the size and for the market. Designers are confronted with one difficulty when frontal beams are to be constructed as deformation zones while giving travellers in all involved vehicles protection during different collision situations in which the front is involved, such as various types of frontal collision, side collisions and collisions from the rear. The dilemma for frontal collisions is that the deformation zone must not be too hard for a symmetrical collision or too soft for an offset collision, it must not be too soft for high collision speeds or, too hard for low collision speeds. ' A second problem is that the vehicles that participate in a collision can have very different weights, and thus become either a winner or a loser. When a light car collides with a car that is significantly heavier, it is subject to a greater deceleration and has difficulty in exploiting the deformation zone of the heavier car in an advantageous manner, since the heavier vehicle has stiffer deformation beams that are adapted such that they cope with collision tests against both hard and soft obstacles. During violent collisions, the lighter vehicle is subjected to a deceleration that is far too high relative to that of the other vehicle, with a large risk that the passenger compartment will be penetrated resulting in personal injury. Smaller passenger cars often to not have the lengths of deformation zones that are required to give the travellers good collision protection at higher collision speeds or during a collision with a heavier vehicle.

During side collisions, it is often the front of one vehicle that drives into the side of another vehicle. The vehicle experiencing the collision from the side has a significantly poorer protection than the other vehicle. The frontal structure provides in most cases a very good protection for those travelling in the vehicle that comes from the side, but it can be devastating for those travelling in the vehicle that experiences the collision from the side. A significantly softer frontal structure would give the travellers in the vehicle experiencing the collision from the side a significantly better protection. In most cases, the collision speeds involved in collisions from the rear are low.

Despite this, many persons are injured in such collisions. Furthermore, many neck injuries are attributed to the relatively stiff deformation beams, in addition to the construction of the seats. If the frontal structure in these cases were softer, these injuries would be eliminated and the costs associated with them reduced. A further difficult collision situation is the case in which the opposite vehicle has relatively high deformation beams such as is the case for certain passenger cars, busses, commercial vehicles and jeeps. In these collision situations, the lower longitudinal deformation beam of a passenger car can be essentially unused while the upper beam, if such exists, is often too soft to absorb collision energy at higher speeds. A jeep or bus can nearly slide over the front of a passenger car and subsequently press in the passenger car's A- columns, which results in a very high risk of personal injury. It would be an improvement in these cases if the upper deformation beam of the passenger car could absorb more collision energy.

A further design problem that arises in all of these different collision situations is that the deformation beams can be prevented from fully absorbing collision energy due to their being buckled or bent instead of folded in the deformation. The energy of absorption may then be less advantageous than if the beams fold.

Vehicle designers are confronted with a difficult dilemma against the background of this description of the problem when vehicles are to be designed in order to cope with both high and low collision speeds, offset and symmetrical collisions, situations in which heavier vehicles collide with lighter ones, side collisions, collisions from the rear, and when the available lengths and heights of deformation zones vary.

Suggested solutions exist with respect to the avoidance of beam buckling. It has been known for many years to provide the deformation beams of a vehicle with fold notches with the aim of achieving an advantageous folding of the beam and in this way avoid buckling. This method reduces the risk of buckling but does not function satisfactorily during oblique collisions from the front. Suggestions are also presented in WO 9822327 Al for the use of explosives in the stiffer parts of the beams and through the release of these a softening is to occur and buckling prevented.

Suggestions for solutions in which the energy-absorbing capability of the deformation beams can be modified in association with a collision are displayed in, for example, WO 9822327 Al and US 4 050 537. Deceleration sensors attached to the front part of the beams are used in WO 9822327 in order to send signals during the initial phase of a collision to a control unit that compares the signals and determines which of the two longitudinal beams has been subject to a collision, and, depending of the offset or a more or less symmetrical collision or in order to prevent buckling, the beams can be influenced with the aid of various explosive charges. The solution that is described, however, provides only information about the collision situation in an initial phase and energy absorption cannot be adapted to different speeds, the weights of the vehicles or the height of the deformation zone. Thus it is an active solution, but can only be applied to a very limited number of collision situations. A solution is described in US 4 050 537 to be able to change the cross-section of a beam from a rectangular to an oval shape with the aid of gas generators, and in this way increase the absorption of energy. This solution, however, is limited to only stiffening the beam, without adaptation to the speeds or weights of the vehicles.

Description The present invention aims to solve the problems that are associated with the prior art.

Thus, the invention concerns the achievement of a deformation zone on a vehicle whose energy absorption can be adapted to many different collision situations, for example, collision speed, the weights of the colliding vehicles, the collision location (for example, more or less symmetrical or offset collision, side collision, collision from the rear) or depending on the height of the deformation beams on the opposite vehicle. It should thus be possible for the deformation zones to increase or decrease their absorption of energy during the collision course and to adapt it to the collision situation.

This is achieved with an arrangement according to claim 1. To be more precise, the invention concerns an arrangement for a vehicle, comprising deformation beams and a deformation zone control system comprising sensor devices arranged along each deformation beam in order to sense impulses and/or deceleration and/or deformation course during a collision course, and a control unit. The deformation beams are monitored during the deformation in that at least two sensor devices are arranged in association with each deformation beam, placed at known positions relative to each other along the deformation beam. These sensor devices are arranged to send signals to the control unit continuously during the collision course and the deformation of the beams, which control unit compares the signals from the sensor devices and based on that information determines the location of the collision, calculates the deformation speed and the change in collision speed during the collision course. The control unit then compares the calculated values with preprogrammed values with the aim of activating means for change of stiffness of the beams as necessary during the collision course, and these means place under pressure and/or change the shape of the deformation beams in one or several stages. The invention furthermore concerns a method for adapting the energy absorption of a vehicle according to the current collision situation by providing the deformation beams of the said vehicle with sensor devices arranged at each deformation beam in order to sense impulses and/or deceleration and/or the deformation course during a collision course, together with a control unit. The deformation beams are monitored during deformation by arranging at least two sensor devices in association with each deformation beam, which sensor devices are placed along each deformation beam with known positions relative to each other. These sensor devices send signals to the control unit continuously during the collision course and the deformation of the beams, which control unit compares the signals from the sensor devices. Based on that information, the control unit determines the location of the collision, calculates the deformation speed and the change in collision speed during the collision course. The control unit then compares the calculated values with preprogrammed values and activates means for change of stiffness of the beams as necessary during the collision course, which means place under pressure and/or change the shape of the deformation beams in one or several stages. The deformation zone control system thus comprises means for sensing deformation that can consist of different types of sensor device, for example devices for contact-free measurement of distance such as a laser and photocells, radio signals, etc., as well as several accelerometers arranged along the beams. When using accelerometers, the deformation speed during the collision course can be measured relative to a non-deformable part of the vehicle. As an alternative, the collaboration between several accelerometers that are arranged along the deformation beams and on non-deformable parts of the vehicle body can provide the signals to the control unit that are required in order to calculate the collision situation. The accelerometers are preferably placed behind the fold notches of the beams such that the sensors that are placed closest to the collision point are exposed to the most powerful impulses and provide signals about the highest acceleration relative to the other accelerometers. If the control system determines, on calculating the incoming signals and comparing these with preprogrammed values, that a change in the energy absorption of the deformation zones must be carried out, the necessary signals are sent to the means for changing rigidity that are included on the deformation beams, for example, gas generators and/or explosive charges, the purpose of which is to change the energy absorption of the beams.

The system thus has information concerning:

1. the location of the collision, which deformation beams are involved.

2. the deformation speed during the initial phase, that is, immediately following the moment of collision.

3. the change of deformation speed after just a few centimetres' deformation of the vehicle, which gives an indication of the weight or kinetic energy of the opposite vehicle.

4. the change of deformation speed at a number of positions during the entire collision course, which gives a more secure basis for calculating the best exploitation of the deformation beams.

5. how much of the deformation zone has been used, and how much remains.

The control unit, which is preprogrammed with information concerning the most advantageous deceleration relative to the collision situation, makes a comparison between the calculated parameters of the collision situation and the preprogrammed values. When the control unit, during a calculation of the difference between the preprogrammed and the calculated values, registers that a deviation lies outside of the tolerances, it will send signals in order to change the energy absorption of the deformation beams. These signals release one or several means of changing stiffness, for example gas cylinders or explosive charges, with the aim of adapting the energy absorption to a level at which the preprogrammed values agree with the calculated. Several calculations are carried out throughout the entire collision course and, if necessary, signals are sent to the means of changing stiffness in order to adapt the energy absorption of the deformation zones in a manner that is most advantageous for the travellers. The deformation beams according to the invention have a design that is advantageous for changing stiffness that can be changed in one or several stages during the collision course. Their manufactured shape is also advantageous from the point of view of space and design, but through an extra bend, either inwards or outwards, their shape can be significantly changed in order to be able to become both softer and stiffer and in this way absorb either lower or higher collision energies than the original manufactured shape allows. The deformation beams can also be designed in two or more longitudinal sections, where each section can be given its own change of shape and stiffness. The sections can preferably be arranged to be released during the collision course in a zigzag pattern, and depending on the design, the shape of either alternating sections up and down or alternating sections to the left and to the right can be changed. This change of shape of the beams can force the beam during the initial phase of the collision into a folded shape that makes it softer in its collision energy absorption. However, the folded shape that has been forcibly produced can also be combined with a change of shape of the equivalent sections such that the beams are stiffened, while the fold positions have been clearly marked through the first change in folding. During a stiffening in which the shapes of both sections on each side have been changed, the beams obtain the appearance of a row of cushions. The energy absorption of the beams is influenced both by the change of shape and by the gas pressure that has changed the shape of the beams. The beams can in this way be weakened or stiffened in a controlled manner. And an adaptation of the energy absorption can take place, depending on how many sections are released. Thus, the stiffness of either one or several of the sections can be changed during the collision course. These can be changed in several stages through several means of changing stiffness being attached to each section.

Rotation sensors, otherwise known as gyros, can be coupled with the sensor system in a further embodiment in order to give information concerning twisting of the beams during the collision course. These can, for example, provide information during a collision obliquely from the front that the beam has been twisted without folding and that therefore the shapes of the beams must be changed in order to absorb the collision energy in a more advantageous manner. Alternatively, twisting of the beams can be registered by arranging several vertically arranged sensor devices in the upper and lower parts of the beam with known positions relative to each other, which send signals to the control unit during the collision course and the deformation of the beam. The control unit compares signals from the sensor devices during the entire collision course such that the location of any buckling of the beam can be determined, and such that signals can be sent as necessary to the means of changing stiffness in those sections or cells that prevent buckling of the beam when activated.

The deformation beam can, in a further embodiment, have several longitudinal sections where the stiffness of each section can be changed in a manner that is advantageous for the absorption of energy. An advantage of arranging a large number of longitudinal sections can be the better precision with which the beam is maintained in an advantageous folding form.

The longitudinal sections of the deformation beams can also have one or several transverse dividing walls, where each dividing wall forms one cell in the section. Each cell can be provided with one or several gas generators or explosive charges. The construction of the deformation beam in this way allows it to be stiffened or weakened in the initial phase in order to counteract breaking tendencies, depending on the collision situation. The rear cells of the beam can be stiffened during the collision course with the aim of exploiting the forward part of the deformation zone in the best manner without buckling.

When four longitudinal beams, two on each side of the vehicle, are used in the frontal structure as a lower and an upper deformation beam, the beams can cope with collision situations, through the deformation zone control system and the means of changing rigidity, in which the opposite vehicle has a relatively high deformation zone such as certain buses, commercial vehicles and jeeps, in a significantly better manner than a traditional frontal design.

In order to adapt the invention to commercial vehicles or to other high vehicles, it is appropriate if the deformation beam according to the invention is attached under the framework beams and extends forwards in the longitudinal direction towards the bumper bar of the vehicle. The deformation beams can also be mounted in pairs on each longitudinal framework beam and angled outwards towards the end point and central point of the bumper bar. An embodiment for a commercial vehicle does not need to be manufactured such that it can be weakened. It can be designed such that it is only stiffened, as necessary. Thus it is appropriate when the invention is applied in a high vehicle, that the deformation beams according to the invention constitute a separate part that is attached to a non-deformable part of the construction of the vehicle. This depends on the fact that the beams that are part of the construction in a high vehicle are placed far too high for them to be used as a deformation zone during a collision with a smaller vehicle. When the invention is applied in a smaller vehicle, a passenger car for example, the beams preferably constitute an integral part of the construction of the vehicle.

Description of the drawings

Applications according to the present invention will be described hereunder with reference to the attached drawing, without this in any way limiting the protective scope. The claims specify further applications for one skilled in the arts.

Fig. 1 shows in side-view a schematic front of an indicated passenger vehicle with the contours of deformation beams la and lb, forward wing 2, bumper bar 3, sensor devices 4 and wheel 5.

Fig. 2 shows a side-view of the deformation beams la and lb that have been equipped with sensor devices 4 and connected to a control unit 6 by cables 7. Fig. 3 A shows a side-view of upper and lower longitudinal beams la and lb in a frontal structure.

Fig. 3B shows an enlarged side-view of the forward part of the beam la in Fig. 3 A, where a longitudinal dividing wall 8 and a transverse dividing wall 9 form cells 11 in the beam la, and where 10 is a powder charge in one cell 11 and where a sensor device 4 has been placed beside a stamp 12 in the beam la.

Fig 4-4C show beams la and lb in side-view and an enlarged cross-section through

A- A, Fig. 4 A. In the cross-section A- A, Fig 4 A and 4A' are shown embodiments of the longitudinal dividing wall 8 of the beams that form sections and an embodiment of an extra double-fold 13 in the sheet-metal that is part of the function of changing the shape of the beams in a collision. Fig 4B and 4C show side-views of the cross-section in Fig. 4 A.

Fig. 5 A shows beams la and lb in side-view, Fig. 5B shows an enlarged cross-section

B-B of lb from Fig. 5 A and Fig. 5C shows an enlargement of the front section of lb. In the cross-section B-B is shown an embodiment of the beam lb with longitudinal dividing wall 8, which forms three sections. The extra bend in the sheet-metal is shown in both internal and external embodiments.

Fig. 6 A shows beams la and lb in side-view and in the enlarged cross-section C-C is shown an embodiment in which the section walls 8 form four asymmetric sections in beam la in Fig. 6B and nine sections in beam lb in Fig. 6C. Fig. 7A shows beams la and lb in side-view and in the enlarged cross-section D-D is shown an embodiment in which the section walls 8 form three sections in beam la in Fig. 7B with gas generator 10 placed in the upper two sections. D-D2 in Fig. 7C shows a change of cross-section D-D after the powder charge 10 of the section has been released. Fig. 8A shows beams la and lb in side-view and in the enlarged cross-section E-E in

Fig. 8B is shown an embodiment where the section walls 8 form three sections in beam la and lb. The gas generator 10 is arranged to fill an airbag 14 placed in the lower section in beam lb according to Fig. 8C.

Fig. 9 A shows beams la and lb in side-view, fold notches 12 and sensor devices 4. Fig. 9B shows an example of how the shape of the beams has been changed in a zigzag pattern.

Fig. 10A shows beams la and lb in the same view as in Fig. 9. Fig. 10B shows examples of how the shape of the beams has been changed in a manner that resembles a row of cushions. Fig. 11 shows the same side-view as Fig. 1. Here is shown the embodiment with contact-free measurement of the deformation beams. A transmitter 15 is attached to a non- deformable part of the body. The reflector 16 is placed far towards the front of the deformation beam. The receiver sensor is incorporated into the transmitter 15.

Description of Embodiments

In Figures 1-11, la and lb denote an upper and a lower deformation beam in a vehicle body, here as the left side of an indicated passenger car. The deformation beams la and lb consist of joined sheet metal profiles, where the external shape forms a rectangular beam in the form of a box. The beams la and lb have internal dividing walls 8 that form sections in the longitudinal direction of the beam. The sections can be divided by transverse dividing walls 9 such that cells 11 are formed in the sections of the beam.

Several sensor devices 4 are arranged in each beam la and lb that send signals to a control unit 6 during a collision course. The sensors are also placed at the bumper bar 3 in one embodiment, such that the impulse is registered at as early a stage as possible.

In Figures 4-7 are shown several cross-sections and embodiments of beams la and lb. Different designs of the notches 13 of the material of the beam are shown. A change of the cross-section from D-D to D-D2 is shown in Fig. 7 following the release of powder charge 10.

A cross-section E-E of la and lb is shown in Fig. 8 where the lower profile lb in one embodiment has an airbag 14 in order to prevent leakage of gas between the sheet metal profiles.

Depending on the design of the car, the design of the beams and the need for exact values, different types of sensor devices 4 are preferably used, and combinations of different types, that collaborate in providing correct information to the control unit 6.

Fig 9 A shows the beams la and lb in side-view, fold notches 12 and sensor devices 4. Fig. 9B shows an example of how the shape of the beams has been changed in a zigzag pattern.

Fig. 10A shows beams la and lb in the same view as in Fig. 9. Fig. 10B shows an example of how the shape of the beams has been changed in a manner that resembles a row of cushions. Fig. 11 shows the same side-view as Fig. 1. In this case, the embodiment with contact- free measurement of the deformation beams is shown. A transmitter 15 is attached to a non- deformable part of the body. The reflector 16 is placed far towards the front of the deformation beam. The receiver sensor is incorporated into the transmitter 15.

The components that comprise the arrangement consist principally of: 1. Sensor devices 4, such as deformation speed sensors and/or different types of accelerometer. The sensor devices can also be comprised of devices for contact-free measurement of distance, such as laser sensors and photocells, radios, sound sensors, etc.

2. A control unit 6, which receives signals from the sensor devices and based on these signals calculates speed, determines the position of the collision point, compares the calculated values with preprogrammed values and, where necessary, transmits signals to the means 10 of changing stiffness.

3. Means 10 of changing stiffness, for example, gas generators such as pyrotechnical devices (powder charges) or gas accumulators or explosive charges, which produce a gas pressure in the cavities of the beams, sections or cells, in order to change the shape of the beam (see Fig. 7) and make the deformation beams stiffer.

4. Cushions 14 similar to airbags, which are placed in the cavities of beams, sections and/or cells. These are filled by one or several gas generators and are used where the gas pressure is to be prevented from leaking in the construction of the beam. 5. One or several energy-absorbing beams la, lb that can change shape from a design that is advantageous for the vehicle manufacturer to a structure that is advantageous for the absorption of energy using means for changing stiffness, as is shown in Fig. 7. The deformation beams la, lb can consist in the frontal structure of one or several sections that have a shape that resembles the figure 3 or 8 and whose shape can be changed in one or several stages by the gas pressure that, for example, one or several gas generators provide, in order to be able to absorb a much higher collision energy. The beams may also be weakened by changes of shape that produce weakness or by explosive charges.

Different embodiments of the invention will now be described in the following text:

Alternative 1: With the Aid of Sensors of Deformation Speed

The deformation speed is measured during a collision through a first deformation speed sensor 4 sending a signal to the control unit 6. The control unit 6, which has been preprogrammed with information concerning the lengths of the deformation zones and the most advantageous energy absorption with respect to collision speed and situation, compares the measured values with the preprogrammed values. After a deformation of a further few centimetres, a new measurement is made by the next deformation speed sensor, the control unit 6 again compares the two values, and then the change in the deformation speed is calculated. The values are then compared with the preprogrammed values and if the deformation speed is too high, the control unit sends a signal either directly or via a control box to release one or several gas generators 10.

Alternative 2: With the Aid of Contact-Free Measurement The location of the collision and the collision course are calculated during a collision by exploiting means for contact-free measurement of distance, also known as triangulation. Reflectors are attached in association with the forward end-points of the deformation beams, and transmitters and receiver sensors are attached to non-deformable parts of the body. The changes in the positions of the beams are calculated during the collision course by the transmitters and the receiver sensors with known positions relative to each other reading a change of angle of the reflector that is attached to the end-point of the deformation beam. The control unit, which has been preprogrammed with information about the lengths of the deformation zones and the most advantageous absorption of energy with respect to collision speed and situation, compares the preprogrammed values with the measured values during the collision. Signals are sent during the entire collision course from the strategically placed sensors and reflectors to the control unit 6. Information is provided in this manner about the deformation speed and a comparison with the preprogrammed values can take place. Depending on whether the values in the comparison are too high or too low, signals are sent from the control unit, directly or via a control box, to release one or several means 10 of changing stiffness, for example gas generators, in order to stiffen or weaken the deformation zone. Means of contact-free measurement can preferably consist of laser or radio signals, but, for example, infra-red or sound signals can also be applied.

Alternative 3: With the Aid of Gravitation Sensors (Accelerometers) The location of the point of collision and the deformation course are calculated during a collision through a comparison taking place between incoming signals from several accelerometers that have been attached to the deformation beams. A first accelerometer 4, placed far forwards in the deformation zone (la, lb, 3), will be initially exposed during a collision to a higher deceleration than sensors that lie behind it. The sensors that lie behind it are arranged such that they lie behind a fold notch. One accelerometer is placed on a non- deformable part of the body. The various sensors are exposed during a collision to different decelerations, and the differences in the signals are recorded by the control unit. The signals given are continuously compared during the collision course. As the collision course progresses, the acceleration at the first accelerometer decreases, while the accelerometers that have been placed behind it are exposed to relatively higher decelerations. The control unit 6 calculates the parameters of the collision situation based on the incoming signals and compares these with preprogrammed information concerning the lengths of the deformation zones and the most advantageous energy absorption with respect to collision speed and situation. If the control unit 6 determines that a change in energy absorption must take place, signals are sent from the control unit 6, either directly or through a control box, to release one or several means 10 of changing stiffness, for example gas generators, in order to stiffen or weaken the deformation zone.

It is a characteristic of all embodiments that a gas generator 10, which is released by the signals that are sent from the control unit 6, produces within the space of a few thousandths of a second a known volume of gas that produces such a pressure that the shapes of the beams that are influenced by it are reformed in order to change the absorption of energy. The control unit after a further few centimetres' deformation carries out a further measurement of the deformation speed and again compares the measured values with the preprogrammed values. If the deformation speed is too high, a further one or several gas generators are released that can increase the pressure in the beam and further change the shape of the beam. If, on the other hand, the value of the comparison lies within the tolerances when compared with the preprogrammed values, no further gas generators are released on this measurement occasion. If the comparison value is too low, the control unit can be preprogrammed to send a signal either to a further gas generator 10 or to explosive charges that deform the beam to such a shape that it obtains a lower energy-absorbing ability. As the collision course proceeds, measurements of the deformation take place and comparisons are made by the control unit with the preprogrammed values. Signals are sent as necessary to release means 10 of changing stiffness in order to stiffen or weaken.

The arrangement according to the invention thus takes into account whether the other vehicle is light or heavy, and whether the collision takes place at high or low speed, the location of the point of collision, whether the collision is offset or symmetrical. For example, if a collision with a relatively light vehicle occurs, no increase in stiffness will take place, and the light vehicle will instead be braked by as much as possible of the deformation zone. A much harder deformation zone will receive the kinetic energy involved in a collision with a heavy vehicle at high speed. The deformation zone at the front will be significantly stiffer during an offset collision at high speed than it is during a symmetric collision at low speed. The frontal structure will be made relatively softer during a side collision. A significant raising of the energy absorption of the upper deformation beams can occur during a collision with a vehicle whose deformation zone is relatively high.

The system is easy to adapt and change for the construction, design, weight and available lengths of deformation zones of various vehicles, to achieve a level of safety that is desired by the car manufacturer and by the market. This collision safety system will protect the travellers from unnecessary high collision forces at low speeds in that as much as possible of the deformation zone is used, while the system will stiffen the deformation zones during collisions at high speeds and prevent the passenger compartment and the internal spaces being pressed together and causing physical injury to the driver or passengers.

Claims

1. An arrangement for a vehicle, comprising deformation beams (la, lb) and a deformation zone control system comprising sensor devices (4) arranged on each deformation beam in order to sense impulses and/or decelerations and/or deformation courses during a collision course, and a control unit (6), characterised in that the deformation beams (la, lb) are monitored during the deformation by at least two sensor devices (4) being arranged in association with each deformation beam placed along the particular deformation beam at known positions relative to each other, which sensor devices (4) are arranged to send signals continuously during the collision course and the deformation of the beam to a control unit (6), which compares the signals from the sensor devices (4), and based on that information determines the location of the point of collision, calculates the speed of deformation and change in collision speed during the collision course, and thereafter compares the calculated values with preprogrammed values with the aim of activating as necessary means (10) of changing stiffness at the beams during the collision course, which means place under pressure and/or change the shapes of the deformation beams in one or several stages.

2. The arrangement according to claim 1, characterised in that the said deformation beams (la, lb) collaborate with each other through each deformation beam having at least two sensor devices (4) connected to the control unit (6), which compares signals from the beams during a collision and calculates the parameters of the collision situation from these signals.

3. The arrangement according to claim 1 or 2, characterised in that the said deformation beams (la, lb) consist of one or several longitudinal sections formed by dividing walls (8), where each section individually and independently of other sections has an external manufactured shape in the shape of a box with continuous inwardly or outwardly folded surfaces (13).

4. The arrangement according to claim 3, characterised in that the said sections are divided into one or several cells (11) formed by transverse dividing walls (9), whereby the said means (10) of changing stiffness place under pressure and change the shape of one or several cells and/or sections in the deformation beams in one or several stages when activated.

5. The arrangement according to claim 3 or 4, characterised in that the said deformation beams (la, lb) have surfaces (13), preferably folded or stamped, that can be folded out, where each longitudinal section, with or without division into cells, has longitudinal or transverse, inwardly or outwardly facing folds that are of the same size or different sizes for each section and/or cell, and that are folded out in one or several stages during the collision course, through the said means (10) of changing stiffness being activated by the control unit (6), in order to change the energy absorption of the deformation beams.

6. The arrangement according to any one of the preceding claims, characterised in that the said deformation beams (la, lb) are equipped with means for detecting the twisting of the beam in order to determine the location of any buckling of the beam.

7. The arrangement according to claim 6, characterised in that the said means for determining twisting can be constituted by a gyrometer.

8. The arrangement according to any one of claims 3-5, characterised in that the said deformation beams (a, lb) constitute deformation zones, where every section and/or cell can have one or several means (10) of changing stiffness.

9. The arrangement according to any one of claim 3-5, and 8, characterised in that the said deformation beams (la, lb) constitute deformation zones, where each section and/or cell has one or several cushions that resemble airbags that are placed in cavities in the beams or between folds with the aim of preventing a gas that has been produced from leaking out through cracks in the sheet metal or other openings in the beam during detonation.

10. The arrangement according to any one of claims 3-7, characterised in that each section and/or cell can be equipped with one or several release holes to another cell or section, or out from the beam, in order that the gas pressure formed during a collision can be released in a controlled manner and not destroy the beam by explosion, but also to be able to fill other cells and sections.

11. The arrangement according to any one of claims 1-7, characterised in that the said means (10) for changing stiffness are constituted by one or several gas generators.

12. The arrangement according to any one of claims 1-7, characterised in that the said means (10) for changing stiffness are constituted by one or several explosive charges.

13. The arrangement according to any one of claims 1-10, characterised in that the said sensor devices (4) are constituted by sensors, for example in the form of accelerometers.

14. The arrangement according to any one of claims 1-10, characterised in that the said sensor devices (4) are constituted by means of contact-free measurement of distance.

15. A method for adapting the energy absorption of a vehicle to a particular collision situation by providing deformation beams (la, lb) of the said vehicle with sensor devices (4) arranged on each deformation beam in order to sense impulses and/or decelerations and/or deformation courses during a collision course, and a control unit (6), characterised in that the said deformation beams (la, lb) are monitored during the deformation by at least two sensor devices (4) being arranged in association with each deformation beam that are placed along the particular deformation beam at known positions relative to each other, which sensor devices (4) send signals continuously during the collision course and the deformation of the beam to a control unit (6) that compares the signals from the sensor devices (4), and based on that information determines the location of the point of collision, calculates the speed of deformation and change in collision speed during the collision course, and thereafter compares the calculated values with preprogrammed values and activates as necessary during the collision course means (10) of changing stiffness at the beams, which means place under pressure and/or change the shape of the deformation beams in one or several stages.